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Sample records for coated xenogenic bone

  1. Alveolar Ridge Preservation Using Xenogeneic Collagen Matrix and Bone Allograft

    PubMed Central

    Parashis, Andreas O.; Kalaitzakis, Charalampos J.; Tatakis, Dimitris N.; Tosios, Konstantinos

    2014-01-01

    Alveolar ridge preservation (ARP) has been shown to prevent postextraction bone loss. The aim of this report is to highlight the clinical, radiographic, and histological outcomes following use of a bilayer xenogeneic collagen matrix (XCM) in combination with freeze-dried bone allograft (FDBA) for ARP. Nine patients were treated after extraction of 18 teeth. Following minimal flap elevation and atraumatic extraction, sockets were filled with FDBA. The XCM was adapted to cover the defect and 2-3 mm of adjacent bone and flaps were repositioned. Healing was uneventful in all cases, the XCM remained in place, and any matrix exposure was devoid of further complications. Exposed matrix portions were slowly vascularized and replaced by mature keratinized tissue within 2-3 months. Radiographic and clinical assessment indicated adequate volume of bone for implant placement, with all planned implants placed in acceptable positions. When fixed partial dentures were placed, restorations fulfilled aesthetic demands without requiring further augmentation procedures. Histological and immunohistochemical analysis from 9 sites (4 patients) indicated normal mucosa with complete incorporation of the matrix and absence of inflammatory response. The XCM + FDBA combination resulted in minimal complications and desirable soft and hard tissue therapeutic outcomes, suggesting the feasibility of this approach for ARP. PMID:25328523

  2. Isolation, cultivation and characterisation of pigeon osteoblasts seeded on xenogeneic demineralised cancellous bone scaffold for bone grafting.

    PubMed

    Harvanová, Denisa; Hornák, Slavomír; Amrichová, Judita; Spaková, Tímea; Mikes, Jaromír; Plsíková, Jana; Ledecký, Valent; Rosocha, Ján

    2014-09-01

    Avian osteoblasts have been isolated particularly from chicken embryo, but data about other functional tissue sources of adult avian osteoblast precursors are missing. The method of preparation of pigeon osteoblasts is described in this study. We demonstrate that pigeon cancellous bone derived osteoblasts have particular proliferative capacity in vitro in comparison to mammalian species and developed endogenous ALP. Calcium deposits formation in vitro was confirmed by alizarin red staining. Only a few studies have attempted to investigate bone grafting and treatment of bone loss in birds. Lack of autologous bone grafts in birds has prompted investigation into the use of avian xenografts for bone augmentation. Here we present a method of xenografting of ostrich demineralised cancellous bone scaffold seeded with allogeneic adult pigeon osteoblasts. Ostrich demineralised cancellous bone scaffold supported proliferation of pigeon osteoblasts during two weeks of co - cultivation in vitro. Scanning electron microscopy demonstrated homogeneous adult pigeon osteoblasts attachment and distribution on the surface of xenogeneic ostrich demineralised cancellous bone. Our preliminary in vitro results indicate that demineralised cancellous bone from ostrich tibia could provide an effective biological support for growth and proliferation of allogeneic osteoblasts derived from cancellous bone of pigeons.

  3. Experimental bone defect healing with xenogenic demineralized bone matrix and bovine fetal growth plate as a new xenograft: radiological, histopathological and biomechanical evaluation.

    PubMed

    Bigham, A S; Dehghani, S N; Shafiei, Z; Nezhad, S Torabi

    2009-02-01

    The following study was designed to evaluate xenogenic bovine demineralized bone matrix (DBM) and new xenograft (Bovine fetal growth plate) effects on bone healing process. Twenty male White New Zealand rabbits were used in this study. In group I (n = 10) the defect was filled by xenogenic DBM and in group II (n = 10) the defect was filled by a segment of bovine fetal growth plate and was fixed by cercelage wire. Radiological, histopathological, and biomechanical evaluations were performed blindly and results scored and analyzed statistically. Statistical tests did not support significant differences between two groups radiographically (P > 0.05). There was a significant difference for union at the 28th postoperative radiologically (P < 0.05). Xenograft was superior to DBM group at the 28th postoperative day for radiological union (P < 0.03). Histopathological and biomechanical evaluation revealed no significant differences between two groups. In conclusion, the results of this study indicate that satisfactory healing occurred in rabbit radius defect filled with xenogenic bovine DBM and xenogenic bovine fetal growth plate. Complications were not identified and healing was faster in two grafting groups.

  4. Transplanted xenogenic bone marrow stem cells survive and generate new bone formation in the posterolateral lumbar spine of non-immunosuppressed rabbits.

    PubMed

    Kim, Hyung-Jun; Park, Jong-Beom; Lee, Jin Kyung; Park, Eun-Young; Park, Eun-Ae; Riew, K Daniel; Rhee, Seung-Koo

    2008-11-01

    Bone marrow stem cells (BMSCs) are pluripotent cells that have been used to facilitate bone repair because of their capability of differentiating into osteoblasts. However, it is well known that the number of BMSCs with osteogenic potential decreases in patients with old age, osteoporosis, and metabolic diseases. In such conditions, xenogenic BMSCs may provide an alternative to autologous BMSCs. In the current study, we investigated the potential of transplanted xenogenic BMSCs to survive and generate new bone formation in the posterolateral lumbar spine of non-immunosuppressed rabbits. The BMSCs were obtained from bilateral femurs of four male rats, cultured and expanded in medium with osteoinduction supplement. The BMSCs (1,000,000 cells) of male rats loaded onto 5 cc compression resistant matrix (CRM; Medtronic Sofamor Danek, USA) were implanted bilaterally onto the L4-5 intertransverse processes of 16 female rabbits (xenogenic BMSCs + CRM group). The 16 female rabbits that received 5 cc CRM alone were used as controls (CRM alone group). To exclude the possibility of migration of BMSCs from the transverse processes of the recipient rabbits, we did not decorticate the transverse processes. No rabbits received any immunosuppressive medications during the experiment. Four rabbits each in both of the experimental and control groups were killed at 1, 2, 4, and 6 months postimplantation, and the lumbar spine underwent radiological and histological analyses for evaluation of new bone formation. The polymerase chain reaction (PCR) for Sry gene (Y-chromosome-specific marker) was used to evaluate the survival of transplanted xenogenic BMSCs. The expression of Sry gene was clearly identified in the lumbar spines of all the 16 rabbits in the xenogenic BMSCs + CRM group at 1-6 months postimplantation. Serial plain radiographs showed gradual resorption of CRM; however, it was difficult to clearly identify the presence of new bone formation due to the radiopacity of the

  5. Characterization of xenogeneic mouse-to-rat bone marrow chimeras. I. Examination of hematologic and immunologic function

    SciTech Connect

    Wade, A.C.; Luckert, P.H.; Tazume, S.; Niedbalski, J.L.; Pollard, M.

    1987-07-01

    Eighteen xenogeneic chimeric rats (survival: greater than 100 days) were established by transplanting bone marrow cells from femurs of 10 gnotobiotic CFW mice into each germfree Sprague-Dawley or Wistar rat. The erythrocytes circulating in the rats were of mouse origin as determined by hemagglutination. Hemoglobin electrophoresis, radial immunodiffusion for IgG, and assay of granulocytic neutrophils for leukocyte alkaline phosphatase verified that true chimerism was achieved. The extent of hematological and immunological reconstitution varied. In general, hematocrit levels were low to normal, white blood cell counts and differentials were within normal limits, and serum protein levels were normal. Levels of circulating IgG of each species were comparable to those of germfree rat and mouse controls. Natural killer (NK) activity was depressed, a phenomenon that may be attributable to the radiation treatment of recipients, or to failure to transfer NK cells or precursors. Mitogenic stimulation reactions were varied, but most chimeric rats demonstrated moderately depressed responses. Reactions as a whole suggested that gnotobiotic rats with xenogeneic bone marrow are incompletely reconstituted, both hematologically and immunologically. No acute graft-versus-host reaction was seen.

  6. Histological and Radiological Analyses of a Maxillary Sinus Lift with Extensive Drilling of the Schneider Membrane Using Xenogeneic Bone

    PubMed Central

    Romano, Marcelo M.; Smanio, Júlia A.; Ferreira, Lorraine B.; Arana-Chavez, Victor E.; Soares, Mário S.

    2014-01-01

    The objective of this study is to report a clinical case of maxillary sinus with lyophilized, xenogeneic graft, in which, despite a large perforation of the sinus membrane, the surgery was not aborted and the results of histological examinations indicate bone neoformation in the surgical area. Results. This case showed that the biomaterials evaluated in this study and the procedure used to place them proved to be biocompatible and presented high osteogenic potential, leading to a successful surgery and osseointegration implant. Conclusion. Positioning Schneider's membrane and filling it with the graft biomaterial helped to achieve the desired osteoconduction and proliferation of bone cells even though the patient had a large perforation of the sinus membrane. PMID:25258686

  7. Tendon Reattachment to Bone in an Ovine Tendon Defect Model of Retraction Using Allogenic and Xenogenic Demineralised Bone Matrix Incorporated with Mesenchymal Stem Cells

    PubMed Central

    2016-01-01

    Background Tendon-bone healing following rotator cuff repairs is mainly impaired by poor tissue quality. Demineralised bone matrix promotes healing of the tendon-bone interface but its role in the treatment of tendon tears with retraction has not been investigated. We hypothesized that cortical demineralised bone matrix used with minimally manipulated mesenchymal stem cells will result in improved function and restoration of the tendon-bone interface with no difference between xenogenic and allogenic scaffolds. Materials and Methods In an ovine model, the patellar tendon was detached from the tibial tuberosity and a complete distal tendon transverse defect measuring 1 cm was created. Suture anchors were used to reattach the tendon and xenogenic demineralised bone matrix + minimally manipulated mesenchymal stem cells (n = 5), or allogenic demineralised bone matrix + minimally manipulated mesenchymal stem cells (n = 5) were used to bridge the defect. Graft incorporation into the tendon and its effect on regeneration of the enthesis was assessed using histomorphometry. Force plate analysis was used to assess functional recovery. Results Compared to the xenograft, the allograft was associated with significantly higher functional weight bearing at 6 (P = 0.047), 9 (P = 0.028), and 12 weeks (P = 0.009). In the allogenic group this was accompanied by greater remodeling of the demineralised bone matrix into tendon-like tissue in the region of the defect (p = 0.015), and a more direct type of enthesis characterized by significantly more fibrocartilage (p = 0.039). No failures of tendon-bone healing were noted in either group. Conclusion Demineralised bone matrix used with minimally manipulated mesenchymal stem cells promotes healing of the tendon-bone interface in an ovine model of acute tendon retraction, with superior mechanical and histological results associated with use of an allograft. PMID:27606597

  8. A New Method for Xenogeneic Bone Graft Deproteinization: Comparative Study of Radius Defects in a Rabbit Model

    PubMed Central

    Lei, Pengfei; Sun, Rongxin; Wang, Long; Zhou, Jialin; Wan, Lifei; Zhou, Tianjian; Hu, Yihe

    2015-01-01

    Background and Objectives Deproteinization is an indispensable process for the elimination of antigenicity in xenograft bones. However, the hydrogen peroxide (H2O2) deproteinized xenograft, which is commonly used to repair bone defect, exhibits limited osteoinduction activity. The present study was designed to develop a new method for deproteinization and compare the osteogenic capacities of new pepsin deproteinized xenograft bones with those of conventional H2O2 deproteinized ones. Methods Bones were deproteinized in H2O2 or pepsin for 8 hours. The morphologies were compared by HE staining. The content of protein and collagen I were measured by the Kjeldahl method and HPLC-MS, respectively. The physical properties were evaluated by SEM and mechanical tests. For in vivo study, X-ray, micro-CT and HE staining were employed to monitor the healing processes of radius defects in rabbit models transplanted with different graft materials. Results Compared with H2O2 deproteinized bones, no distinct morphological and physical changes were observed. However, pepsin deproteinized bones showed a lower protein content, and a higher collagen content were preserved. In vivo studies showed that pepsin deproteinized bones exhibited better osteogenic performance than H2O2 deproteinized bones, moreover, the quantity and quality of the newly formed bones were improved as indicated by micro-CT analysis. From the results of histological examination, the newly formed bones in the pepsin group were mature bones. Conclusions Pepsin deproteinized xenograft bones show advantages over conventional H2O2 deproteinized bones with respect to osteogenic capacity; this new method may hold potential clinical value in the development of new biomaterials for bone grafting. PMID:26719896

  9. Synthetic bone substitute material comparable with xenogeneic material for bone tissue regeneration in oral cancer patients: First and preliminary histological, histomorphometrical and clinical results

    PubMed Central

    Ghanaati, Shahram; Barbeck, Mike; Lorenz, Jonas; Stuebinger, Stefan; Seitz, Oliver; Landes, Constantin; Kovács, Adorján F.; Kirkpatrick, Charles J.; Sader, Robert A.

    2013-01-01

    Background: The present study was first to evaluate the material-specific cellular tissue response of patients with head and neck cancer to a nanocrystalline hydroxyapatite bone substitute NanoBone (NB) in comparison with a deproteinized bovine bone matrix Bio-Oss (BO) after implantation into the sinus cavity. Materials and Methods: Eight patients with tumor resection for oral cancer and severely resorbed maxillary bone received materials according to a split mouth design for 6 months. Bone cores were harvested prior to implantation and analyzed histologically and histomorphometrically. Implant survival was followed-up to 2 years after placement. Results: Histologically, NB underwent a higher vascularization and induced significantly more tartrate-resistant acid phosphatase-positive (TRAP-positive) multinucleated giant cells when compared with BO, which induced mainly mononuclear cells. No significant difference was observed in the extent of new bone formation between both groups. The clinical follow-up showed undisturbed healing of all implants in the BO-group, whereas the loss of one implant was observed in the NB-group. Conclusions: Within its limits, the present study showed for the first time that both material classes evaluated, despite their induction of different cellular tissue reactions, may be useful as augmentation materials for dental and maxillofacial surgical applications, particularly in patients who previously had oral cancer. PMID:24205471

  10. Clinical evaluation of regenerative potential of type I collagen membrane along with xenogenic bone graft in the treatment of periodontal intrabony defects assessed with surgical re-entry and radiographic linear and densitometric analysis

    PubMed Central

    Sowmya, N. K.; Tarun Kumar, A. B.; Mehta, D. S.

    2010-01-01

    Background and Objectives: The primary goal of periodontal therapy is to restore the tooth supporting tissues lost due to periodontal disease. The aim of the present study was to compare the efficacy of combination of type I collagen (GTR membrane) and xenogenic bone graft with open flap debridement (OFD) in treatment of periodontal intrabony defects. Materials and Methods: Twenty paired intrabony defects were surgically treated using split mouth design. The defects were randomly assigned to treatment with OFD + collagen membrane + bone graft (Test) or OFD alone (Control). The clinical efficacy of two treatment modalities was evaluated at 9 month postoperatively by clinical, radiographical, and intrasurgical (re-entry) parameters. The measurements included probing pocket depth (PD), clinical attachment level (CAL), gingival recession (GR), bone fill (BF), bone density (BD) and intra bony component (INTRA). Results: The mean reduction in PD at 0–9 month was 3.3±0.82 mm and CAL gain of 3.40±1.51 mm occurred in the collagen membrane + bone graft (Test) group; corresponding values for OFD (Control) were 2.20±0.63 mm and 1.90±0.57 mm. Similar pattern of improvement was observed when radiographical and intra-surgical (re-entry) post operative evaluation was made. All improvement in different parameters was statistically significant (P< 0.01). Interpretation and Conclusion: Treatment with a combination of collagen membrane and bone graft led to a significantly more favorable clinical outcome in intrabony defects as compared to OFD alone. PMID:20922075

  11. Biodegradable nanocomposite coatings accelerate bone healing: In vivo evaluation

    PubMed Central

    Mehdikhani-Nahrkhalaji, Mehdi; Fathi, Mohammad Hossein; Mortazavi, Vajihesadat; Mousavi, Sayed Behrouz; Akhavan, Ali; Haghighat, Abbas; Hashemi-Beni, Batool; Razavi, Sayed Mohammad; Mashhadiabbas, Fatemeh

    2015-01-01

    Background: The aim of this study was to evaluate the interaction of bioactive and biodegradable poly (lactide-co-glycolide)/bioactive glass/hydroxyapatite (PBGHA) and poly (lactide-co-glycolide)/bioactive glass (PBG) nanocomposite coatings with bone. Materials and Methods: Sol-gel derived 58S bioactive glass nanoparticles, 50/50 wt% poly (lactic acid)/poly (glycolic acid) and hydroxyapatite nanoparticles were used to prepare the coatings. The nanocomposite coatings were characterized by scanning electron microscopy, X-ray diffraction and atomic force microscopy. Mechanical stability of the prepared nanocomposite coatings was studied during intramedullary implantation of coated Kirschner wires (K-wires) into rabbit tibia. Titanium mini-screws coated with nanocomposite coatings and without coating were implanted intramedullary in rabbit tibia. Bone tissue interaction with the prepared nanocomposite coatings was evaluated 30 and 60 days after surgery. The non-parametric paired Friedman and Kruskal-Wallis tests were used to compare the samples. For all tests, the level of significance was P < 0.05. Results: The results showed that nanocomposite coatings remained stable on the K-wires with a minimum of 96% of the original coating mass. Tissue around the coated implants showed no adverse reactions to the coatings. Woven and trabecular bone formation were observed around the coated samples with a minimum inflammatory reaction. PBG nanocomposite coating induced more rapid bone healing than PBGHA nanocomposite coating and titanium without coating (P < 0.05). Conclusion: It was concluded that PBG nanocomposite coating provides an ideal surface for bone formation and it could be used as a candidate for coating dental and orthopedic implants. PMID:25709681

  12. Electrodeposited silk coatings for bone implants

    PubMed Central

    Elia, Roberto; Michelson, Courtney D.; Perera, Austin L.; Brunner, Teresa F.; Harsono, Masly; Leisk, Gray G.; Kugel, Gerard; Kaplan, David L.

    2014-01-01

    The aim of this study was to characterize the mechanical properties and drug elution features of silk protein-based electrodeposited dental implant coatings. Silk processing conditions were modified to obtain coatings with a range of mechanical properties on titanium studs. These coatings were assessed for adhesive strength and dissolution, with properties tuned using water vapor annealing or glycerol incorporation to modulate crystalline content. Coating reproducibility was demonstrated over a range of silk concentrations from 1 to 10%. Surface roughness of titanium substrates was altered using industry relevant acid etching and grit blasting, and the effect of surface topography on silk coating adhesion was assessed. Florescent compounds were incorporated into the silk coatings, which were modulated for crystalline content, to achieve four days of sustained release of the compounds. This silk electrogelation technique offers a safe and relatively simple approach to generate mechanically robust, biocompatible and degradable implant coatings that can also be functionalized with bioactive compounds to modulate the local regenerative tissue environment. PMID:25545462

  13. Porous coatings from wire mesh for bone implants

    DOEpatents

    Sump, Kenneth R.

    1986-01-01

    A method of coating areas of bone implant elements and the resulting implant having a porous coating are described. Preselected surface areas are covered by a preform made from continuous woven lengths of wire. The preform is compressed and heated to assure that diffusion bonding occurs between the wire surfaces and between the surface boundaries of the implant element and the wire surfaces in contact with it. Porosity is achieved by control of the resulting voids between the bonded wire portions.

  14. Serum albumin coating of demineralized bone matrix results in stronger new bone formation.

    PubMed

    Horváthy, Dénes B; Vácz, Gabriella; Szabó, Tamás; Szigyártó, Imola C; Toró, Ildikó; Vámos, Boglárka; Hornyák, István; Renner, Károly; Klára, Tamás; Szabó, Bence T; Dobó-Nagy, Csaba; Doros, Attila; Lacza, Zsombor

    2016-01-01

    Blood serum fractions are hotly debated adjuvants in bone replacement therapies. In the present experiment, we coated demineralized bone matrices (DBM) with serum albumin and investigated stem cell attachment in vitro and bone formation in a rat calvaria defect model. In the in vitro experiments, we observed that significantly more cells adhere to the serum albumin coated DBMs at every time point. In vivo bone formation with albumin coated and uncoated DBM was monitored biweekly by computed tomography until 11 weeks postoperatively while empty defects served as controls. By the seventh week, the bone defect in the albumin group was almost completely closed (remaining defect 3.0 ± 2.3%), while uncoated DBM and unfilled control groups still had significant defects (uncoated: 40.2 ± 9.1%, control: 52.4 ± 8.9%). Higher density values were also observed in the albumin coated DBM group. In addition, the serum albumin enhanced group showed significantly higher volume of newly formed bone in the microCT analysis and produced significantly higher breaking force and stiffness compared to the uncoated grafts (peak breaking force: uncoated: 15.7 ± 4 N, albumin 46.1 ± 11 N). In conclusion, this investigation shows that implanting serum albumin coated DBM significantly reduces healing period in nonhealing defects and results in mechanically stronger bone. These results also support the idea that serum albumin coating provides a convenient milieu for stem cell function, and a much improved bone grafting success can be achieved without the use of exogenous stem cells.

  15. Nano hydroxyapatite-coated implants improve bone nanomechanical properties.

    PubMed

    Jimbo, R; Coelho, P G; Bryington, M; Baldassarri, M; Tovar, N; Currie, F; Hayashi, M; Janal, M N; Andersson, M; Ono, D; Vandeweghe, S; Wennerberg, A

    2012-12-01

    Nanostructure modification of dental implants has long been sought as a means to improve osseointegration through enhanced biomimicry of host structures. Several methods have been proposed and demonstrated for creating nanotopographic features; here we describe a nanoscale hydroxyapatite (HA)-coated implant surface and hypothesize that it will hasten osseointegration and improve its quality relative to that of non-coated implants. Twenty threaded titanium alloy implants, half prepared with a stable HA nanoparticle surface and half grit-blasted, acid-etched, and heat-treated (HT), were inserted into rabbit femurs. Pre-operatively, the implants were morphologically and topographically characterized. After 3 weeks of healing, the samples were retrieved for histomorphometry. The nanomechanical properties of the surrounding bone were evaluated by nanoindentation. While both implants revealed similar bone-to-implant contact, the nanoindentation demonstrated that the tissue quality was significantly enhanced around the HA-coated implants, validating the postulated hypothesis.

  16. Are allogenic or xenogenic screws and plates a reasonable alternative to alloplastic material for osteosynthesis--a histomorphological analysis in a dynamic system.

    PubMed

    Jacobsen, C; Obwegeser, J A

    2010-12-01

    Despite invention of titanium and resorbable screws and plates, still, one of the main challenges in bone fixation is the search for an ideal osteosynthetic material. Biomechanical properties, biocompatibility, and also cost effectiveness and clinical practicability are factors for the selection of a particular material. A promising alternative seems to be screws and plates made of bone. Recently, xenogenic bone pins and screws have been invented for use in joint surgery. In this study, screws made of allogenic sheep and xenogenic human bone were analyzed in a vital and dynamic sheep-model and compared to conventional titanium screws over a standard period of bone healing of 56 days with a constant applied extrusion force. Biomechanical analysis and histomorphological evaluation were performed. After 56 days of insertion xenogenic screws made of human bone showed significantly larger distance of extrusion of on average 173.8 μm compared to allogenic screws made of sheep bone of on average 27.8 and 29.95 μm of the titanium control group. Severe resorption processes with connective tissue interposition were found in the histomorphological analysis of the xenogenic screws in contrast to new bone formation and centripetal vascularization of the allogenic bone screw, as well as in processes of incorporation of the titanium control group. The study showed allogenic cortical bone screws as a substantial alternative to titanium screws with good biomechanical properties. In contrast to other reports a different result was shown for the xenogenic bone screws. They showed insufficient holding strength with confirmative histomorphological signs of degradation and insufficient osseointegration. Before common clinical use of xenogenic osteosynthetic material, further evaluation should be performed.

  17. Strontium and zoledronate hydroxyapatites graded composite coatings for bone prostheses.

    PubMed

    Boanini, Elisa; Torricelli, Paola; Sima, Felix; Axente, Emanuel; Fini, Milena; Mihailescu, Ion N; Bigi, Adriana

    2015-06-15

    Both strontium and zoledronate (ZOL) are known to be useful for the treatment of bone diseases associated to the loss of bone substance. In this work, we applied an innovative technique, Combinatorial Matrix-Assisted Pulsed Laser Evaporation (C-MAPLE), to deposit gradient thin films with variable compositions of Sr-substituted hydroxyapatite (SrHA) and ZOL modified hydroxyapatite (ZOLHA) on Titanium substrates. Compositional gradients were obtained by simultaneous laser vaporization of the two distinct material targets. The coatings display good crystallinity and granular morphology, which do not vary with composition. Osteoblast-like MG63 cells and human osteoclasts were co-cultured on the thin films up to 21 days. The results show that Sr counteracts the negative effect of relatively high concentration of ZOL on osteoblast viability, whereas both Sr and ZOL enhance extracellular matrix deposition. In particular, ZOL promotes type I collagen production, whereas Sr increases the production of alkaline phosphatase. Moreover, ZOL exerts a greater effect than Sr on osteoprotegerin/RANKL ratio and, as a consequence, on the reduction of osteoclast proliferation and activity. The deposition method allows to modulate the composition of the thin films and hence the promotion of bone growth and the inhibition of bone resorption.

  18. Assessment of bone ingrowth potential of biomimetic hydroxyapatite and brushite coated porous E-beam structures.

    PubMed

    Biemond, J Elizabeth; Eufrásio, Tatiane S; Hannink, Gerjon; Verdonschot, Nico; Buma, Pieter

    2011-04-01

    The bone ingrowth potential of biomimetic hydroxyapatite and brushite coatings applied on porous E-beam structure was examined in goats and compared to a similar uncoated porous structure and a conventional titanium plasma spray coating. Specimens were implanted in the iliac crest of goats for a period of 3 (4 goats) or 15 weeks (8 goats). Mechanical implant fixation generated by bone ingrowth was analyzed by a push out test. Histomorphometry was performed to assess the bone ingrowth depth and bone implant contact. The uncoated and hydroxyapatite-coated cubic structure had significantly higher mechanical strength at the interface compared to the Ti plasma spray coating at 15 weeks of implantation. Bone ingrowth depth was significantly larger for the hydroxyapatite- and brushite-coated structures compared to the uncoated structure. In conclusion, the porous E-beam surface structure showed higher bone ingrowth potential compared to a conventional implant surface after 15 weeks of implantation. Addition of a calcium phosphate coating to the E-beam structure enhanced bone ingrowth significantly. Furthermore, the calcium phosphate coating appears to work as an accelerator for bone ingrowth.

  19. Effect of surface roughness and calcium phosphate coating on the implant/bone response.

    PubMed

    Hayakawa, T; Yoshinari, M; Nemoto, K; Wolke, J G; Jansen, J A

    2000-08-01

    The influence of surface roughness and calcium phosphate (Ca-P) coating on the bone response of titanium implants was investigated. Four types of titanium implants, i.e. as-machined, grit blasted, as-machined with Ca-P sputter coating, and grit blasted with Ca-P sputter coating, were prepared. The Ca-P sputter-coating, produced by using the RF magnetron sputter technique, was rapid heat-treated with infrared radiation at 600 degrees C. These implants were inserted into the left and right femoral condyles and the left and right tibial diaphyses of the rabbits. After implantation periods of 2 and 12 weeks, the bone-implant interface was evaluated histologically and histomorphometrically. Histological evaluation revealed no new bone formation around different implant materials after 2 weeks of implantation. After 12 weeks, bone healing was almost completed. For both tibial and femoral implants, Ca-P coated implants always showed a higher amount of bone contact than either of the non-coated implants. On the other hand, surface roughness improved only the response to implants inserted into the tibial diaphysis. On the basis of these findings, we concluded that 1) deposition of a sputtered Ca-P coating on an implant has a beneficial effect on the bone response to this implant during the healing phase, and 2) besides implant surface conditions the bone response is also determined by local implant site conditions.

  20. Interfacial and biological properties of the gradient coating on polyamide substrate for bone substitute.

    PubMed

    Huang, Di; Niu, Lulu; Wei, Yan; Guo, Meiqing; Zuo, Yi; Zou, Qin; Hu, Yinchun; Chen, Weiyi; Li, Yubao

    2014-10-06

    Fabrication of bioactive and mechanical matched bone substitutes is crucial for clinical application in bone defects repair. In this study, nano-hydroxyapatite/polyamide (nHA/PA) composite was coated on injection-moulded PA by a chemical corrosion and phase-inversion technique. The shear strength, gradient composition and pore structure of the bioactive coating were characterized. Osteoblast-like MG63 cells were cultured on pure PA and composite-coated PA samples. The cells' adhesion, spread and proliferation were determined using MTT assay and microscopy. The results confirm that the samples with the nHA/PA composite coating have better cytocompatibility and have no negative effects on cells. To investigate the in vivo biocompatibility, both pure PA and composite-coated PA cylinders were implanted in the trochlea of rabbit femurs and studied histologically, and the bonding ability with bone were determined using push-out tests. The results show that composite-coated implants exhibit better biocompatibility and the shear strength of the composite-coated implants with host bone at 12 weeks can reach 3.49±0.42 MPa, which is significantly higher than that of pure PA implants. These results indicate that composite-coated PA implants have excellent biocompatibility and bonding abilities with host bone and they have the potential to be applied in repair of bone defects.

  1. Mechanical and bone ingrowth properties of a polymer-coated, porous, synthetic, coralline hydroxyapatite bone-graft material.

    PubMed

    Tencer, A F; Woodard, P L; Swenson, J; Brown, K L

    1988-01-01

    CHAG, that is, porous hydroxyapatite hydrothermally converted from the calcium carbonate exoskeleton of a coral (genus Goniopora), has been shown to be effective as a scaffold for bone ingrowth. The large pores in the material, however, resulted in low compressive strengths. Compressive testing was performed to assess the changes in mechanical properties by coating the internal surfaces of CHAG with DL-PLA. Plugs of CHAG with thick (3:1 chloroform to DL-PLA by weight), medium (10:1), and thin (30:1) coatings as well as uncoated CHAG were then implanted transcortically in the proximal third of the diaphysis of rabbit tibiae to assess the in vivo response. The mechanical tests demonstrated significantly improved compressive strength, stiffness, and energy absorption for coated specimens compared with uncoated specimens. Coated specimens were not significantly different from canine tibial cancellous bone in strength and stiffness although they achieved only 36% of the energy absorption capacity. Specimens from rabbit tibiae were harvested at 3, 12, and 24 weeks for interface shear strength determination and contralaterally for histological and histomorphometric assessment. At 12 weeks, uncoated CHAG plugs developed an average ultimate interface shear stress of 26.7 MPa compared with 17 MPa for specimens with 30:1 coatings and 8 MPa for specimens with 10:1 and 3:1 coatings. At 24 weeks, there were no significant differences in shear stress between any of the specimens. Histomorphometric assessments showed that the ratio of area fraction of new bone to area fraction of new bone and void space increased from 68-70% for specimens with 3:1 and 10:1 coatings at 3 weeks to 85.5-89.5% at 24 weeks. In comparison, uncoated and 30:1 specimens had area fraction ratios of about 82% at 3 weeks and 93% at 24 weeks. Histologic sections demonstrated direct apposition of new bone to both the coating and the hydroxyapatite as well as degradation of the coating.

  2. Coating with a Modular Bone Morphogenetic Peptide Promotes Healing of a Bone-Implant Gap in an Ovine Model

    PubMed Central

    Lu, Yan; Lee, Jae Sung; Nemke, Brett; Graf, Ben K.; Royalty, Kevin; Illgen, Richard; Vanderby, Ray; Markel, Mark D.; Murphy, William L.

    2012-01-01

    Despite the potential for growth factor delivery strategies to promote orthopedic implant healing, there is a need for growth factor delivery methods that are controllable and amenable to clinical translation. We have developed a modular bone growth factor, herein termed “modular bone morphogenetic peptide (mBMP)”, which was designed to efficiently bind to the surface of orthopedic implants and also stimulate new bone formation. The purpose of this study was to coat a hydroxyapatite-titanium implant with mBMP and evaluate bone healing across a bone-implant gap in the sheep femoral condyle. The mBMP molecules efficiently bound to a hydroxyapatite-titanium implant and 64% of the initially bound mBMP molecules were released in a sustained manner over 28 days. The results demonstrated that the mBMP-coated implant group had significantly more mineralized bone filling in the implant-bone gap than the control group in C-arm computed tomography (DynaCT) scanning (25% more), histological (35% more) and microradiographic images (50% more). Push-out stiffness of the mBMP group was nearly 40% greater than that of control group whereas peak force did not show a significant difference. The results of this study demonstrated that mBMP coated on a hydroxyapatite-titanium implant stimulates new bone formation and may be useful to improve implant fixation in total joint arthroplasty applications. PMID:23185610

  3. Specific tolerance induction across a xenogeneic barrier: Production of mixed rat/mouse lymphohematopoietic chimeras using a nonlethal preparative regimen

    SciTech Connect

    Sharabi, Y.; Aksentijevich, I.; Sundt, T.M. 3d.; Sachs, D.H.; Sykes, M. )

    1990-07-01

    The development of safe methods for inducing donor-specific tolerance across xenogeneic barriers could potentially relieve the critical shortage of allograft donors that currently limits the applicability of organ transplantation. We report here that such tolerance can be induced in a xenogeneic combination (rat----mouse) using a nonmyeloablative and nonlethal preparative regimen. Successful induction of chimerism and donor-specific transplantation tolerance required pretreatment of recipients with monoclonal antibodies (mAbs) against NK1.1, Thy-1.2, CD4 and CD8, followed by administration of 3 Gy whole body radiation (WBI), 7 Gy thymic irradiation, and infusion of T cell-depleted rat bone marrow cells (BMC). Rat cells appeared among peripheral blood lymphocytes (PBL) of such recipients by 2-3 wk, and rat T cells by 2-5 wk following bone marrow transplantation (BMT). Donor-type rat skin grafts placed 4 mo after BMT were accepted, while simultaneously placed non-donor-type rat skin grafts were promptly rejected. In addition to its clinical potential, the ability to induce donor-specific tolerance across xenogeneic barriers using such a nonlethal preparative regimen provides a valuable model for the study of mechanisms of xenogeneic transplantation tolerance.

  4. [Antitumoral effect of xenogenic substances in vivo and in vitro].

    PubMed

    Munder, P G; Stiefel, T; Widmann, K H; Theurer, K

    1982-04-01

    The proliferation of various tumour cells was inhibited in vivo and in vitro after application of/or incubation with xenogeneic liver tissue. The development of s.c.-implanted meth-A-sarcoma was blocked by the prophylactic injection of these preparations. In addition firmly established tumours regressed under therapy. Preparations obtained from xenogeneic organs like thymus, placenta or brain had a similar antitumor activity. A mixture of various xenogeneic tissues from different species had a much higher therapeutic efficiency. In the Meth-A-system the xenogeneic material surpassed the antineoplastic effect of rather high doses of cyclophosphamide. The preparations showed no side-effects in mice and rats. These results were supported by experiments in tissue culture. This new antitumour activity of xenogeneic tissues in vivo is interpreted as mediated by an increased host defense. The results in tissue culture however, indicate also a direct regulatory effect on cells.

  5. Self-dissolution assisted coating on magnesium metal for biodegradable bone fixation devices

    NASA Astrophysics Data System (ADS)

    Khakbaz, Hadis; Walter, Rhys; Gordon, Timothy; Bobby Kannan, M.

    2014-12-01

    An attempt was made to develop a self-dissolution assisted coating on a pure magnesium metal for potential bone fixation implants. Magnesium phosphate cement (MPC) was coated successfully on the magnesium metal in ammonium dihydrogen phosphate solution. The in vitro degradation behaviour of the MPC coated metal was evaluated using electrochemical techniques. The MPC coating increased the polarisation resistance (RP) of the metal by ˜150% after 2 h immersion in simulated body fluid (SBF) and reduced the corrosion current density (icorr) by ˜80%. The RP of the MPC coated metal remained relatively high even after 8 h immersion period. However, post-degradation analysis of the MPC coated metal revealed localized attack. Hence, the study suggests that MPC coating alone may not be beneficial, but this novel coating could provide additional protection if used as a precursor for other potential coatings such as biodegradable polymers or calcium phosphates.

  6. Long-term antibiotic delivery by chitosan-based composite coatings with bone regenerative potential

    NASA Astrophysics Data System (ADS)

    Ordikhani, F.; Simchi, A.

    2014-10-01

    Composite coatings with bone-bioactivity and drug-eluting capacity are considered as promising materials for titanium bone implants. In this work, drug-eluting chitosan-bioactive glass coatings were fabricated by a single-step electrophoretic deposition technique. Drug-loading and -releasing capacity of the composite coatings were carried out using the vancomycin antibiotic. Uniform coatings with a thickness of ∼55 μm containing 23.7 wt% bioactive glass particles and various amounts of the antibiotic (380-630 μg/cm2) were produced. The coatings were bioactive in terms of apatite-forming ability in simulated body fluid and showed favorable cell adhesion and growth. In vitro biological tests also indicated that the composite coatings had better cellular affinity than pristine chitosan coatings. The in vitro elution kinetics of the composite coating revealed an initial burst release of around 40% of the drug within the first elution step of 1 h and following by a continuous eluting over 4 weeks, revealing long-term drug-delivering potential. Antibacterial tests using survival assay against Gram-positive Staphylococcus aureus bacteria determined the effect of vancomycin release on reduction of infection risk. Almost no bacteria were survived on the coatings prepared from the EPD suspension containing ≥0.5 g/l vancomycin. The developed chitosan-based composite coatings with bone bioactivity and long-term drug-delivery ability may be potentially useful for metallic implants to reduce infection risk.

  7. Recovery of hair coat color in Gray Collie (cyclic neutropenia)-normal bone marrow transplant chimeras.

    PubMed Central

    Yang, T. J.

    1978-01-01

    Gray Collie-normal bone marrow transplantation chimeras showed normal coloration of the hair coat on tails and several other areas 2 years after successful transplantation of bone marrow to correct cyclic neutropenia of the Gray Collie syndrome. Images Figures 1-2 PMID:347941

  8. Impact of Mixed Xenogeneic Porcine Hematopoietic Chimerism on Human NK Cell Recognition in a Humanized Mouse Model.

    PubMed

    Li, H W; Vishwasrao, P; Hölzl, M A; Chen, S; Choi, G; Zhao, G; Sykes, M

    2017-02-01

    Mixed chimerism is a promising approach to inducing allograft and xenograft tolerance. Mixed allogeneic and xenogeneic chimerism in mouse models induced specific tolerance and global hyporesponsiveness, respectively, of host mouse natural killer (NK) cells. In this study, we investigated whether pig/human mixed chimerism could tolerize human NK cells in a humanized mouse model. Our results showed no impact of induced human NK cell reconstitution on porcine chimerism. NK cells from most pig/human mixed chimeric mice showed either specifically decreased cytotoxicity to pig cells or global hyporesponsiveness in an in vitro cytotoxicity assay. Mixed xenogeneic chimerism did not hamper the maturation of human NK cells but was associated with an alteration in NK cell subset distribution and interferon gamma (IFN-γ) production in the bone marrow. In summary, we demonstrate that mixed xenogeneic chimerism induces human NK cell hyporesponsiveness to pig cells. Our results support the use of this approach to inducing xenogeneic tolerance in the clinical setting. However, additional approaches are required to improve the efficacy of tolerance induction while ensuring adequate NK cell functions.

  9. Bone growth on and resorption of calcium phosphate coatings obtained by pulsed laser deposition.

    PubMed

    Clèries, L; Fernández-Pradas, J M; Morenza, J L

    2000-01-01

    Three different calcium phosphate coatings of crystalline hydroxyapatite (HA), alpha- and beta-tricalcium phosphate (alpha+beta-TCP), or amorphous calcium phosphate (ACP) obtained by pulsed laser deposition on Ti-6Al-4V were incubated in a potentially osteogenic primary cell culture (rat bone marrow) in order to evaluate the amount and mode of mineralized bone matrix formation after 2 weeks with special emphasis on the type of interfacial structure that was created. Evaluation techniques included fluorescence labeling and scanning electron microscopy. The resistance to cellular resorption by osteoclasts was also studied. Bone matrix delaminated from the ACP coatings, while it remained on the HA and the alpha+beta-TCP coatings even after fracturing. A cementlike line was seen as the immediate contiguous interface with the nondegrading dense HA surface and with the surface of the remaining porous beta-TCP coating. Highly dense and crystalline HA coatings do not dissolve but are capable of establishing a strong bond with the bone matrix grown on top. Chemical and mechanical bonding were considered in this case. Cellular resorption was practically not observed on the HA coatings, but it was observed on the alpha+beta-TCP coatings. Resorption took place as dissolution that was due to the acidic microenvironment.

  10. Increased Release Time of Antibiotics from Bone Allografts through a Novel Biodegradable Coating

    PubMed Central

    Madácsi, Edit; Kalugyer, Pálma; Vácz, Gabriella; Horváthy, Dénes B.; Szendrői, Miklós; Han, Weiping; Lacza, Zsombor

    2014-01-01

    The use of bone allografts is contraindicated in septic revision surgery due to the high risk of graft reinfection. Antibiotic release from the graft may solve the problem and these combinations can theoretically be used for prevention or even therapy of infection. The present study investigated whether amoxicillin, ciprofloxacin, and vancomycin alone or in combination with chitosan or alginate are suitable for short-term or long-term bone coating. Human bone allografts were prepared from femoral head and lyophilized. Antibiotic coating was achieved by incubating the grafts in antibiotic solution and freeze-drying again. Two biopolymers chitosan and alginate were used for creating sustained-release implantable coatings and the drug release profile was characterized in vitro by spectrophotometry. Using lyophilization with or without chitosan only resulted in short-term release that lasted up to 48 hours. Alginate coating enabled a sustained release that lasted for 8 days with amoxicillin, 28 days with ciprofloxacin coating, and 50 days with vancomycin coating. Using only implantable biodegradable allograft and polymers, a sustained release of antibiotics was achieved with ciprofloxacin and vancomycin for several weeks. Since the calculated daily release of the antibiotic was lower than the recommended IV dose, the calcium alginate coated bone graft can support endoprosthesis revision surgery. PMID:25045678

  11. Effect of trehalose coating on basic fibroblast growth factor release from tailor-made bone implants.

    PubMed

    Choi, Sungjin; Lee, Jongil; Igawa, Kazuyo; Suzuki, Shigeki; Mochizuki, Manabu; Nishimura, Ryohei; Chung, Ung-il; Sasaki, Nobuo

    2011-12-01

    Artificial bone implants are often incorporated with osteoinductive factors to facilitate early bone regeneration. Calcium phosphate, the main component in artificial bone implants, strongly binds these factors, and in a few cases, the incorporated proteins are not released from the implant under conditions of physiological pH, thereby leading to reduction in their osteoinductivity. In this study, we coated tailor-made bone implants with trehalose to facilitate the release of basic fibroblast growth factor (bFGF). In an in vitro study, mouse osteoblastic cells were separately cultured for 48 hr in a medium with a untreated implant (T-), trehalose-coated implant (T+), bFGF-incorporated implant (FT-), and bFGF-incorporated implant with trehalose coating (FT+). In the FT+ group, cell viability was significantly higher than that in the other groups (P<0.05). Scanning electron microscopy (SEM) and X-ray diffraction (XRD) revealed that trehalose effectively covered the surface of the artificial bone implant without affecting the crystallinity or the mechanical strength of the artificial bone implant. These results suggest that coating artificial bone implants with trehalose could limit the binding of bFGF to calcium phosphate.

  12. Effects of zinc-substituted nano-hydroxyapatite coatings on bone integration with implant surfaces*

    PubMed Central

    Zhao, Shi-fang; Dong, Wen-jing; Jiang, Qiao-hong; He, Fu-ming; Wang, Xiao-xiang; Yang, Guo-li

    2013-01-01

    Objective: The purpose of this study was to investigate the effects of a zinc-substituted nano-hydroxyapatite (Zn-HA) coating, applied by an electrochemical process, on implant osseointegraton in a rabbit model. Methods: A Zn-HA coating or an HA coating was deposited using an electrochemical process. Surface morphology was examined using field-emission scanning electron microscopy. The crystal structure and chemical composition of the coatings were examined using an X-ray diffractometer (XRD) and Fourier transform infrared spectroscopy (FTIR). A total of 78 implants were inserted into femurs and tibias of rabbits. After two, four, and eight weeks, femurs and tibias were retrieved and prepared for histomorphometric evaluation and removal torque (RTQ) tests. Results: Rod-like HA crystals appeared on both implant surfaces. The dimensions of the Zn-HA crystals seemed to be smaller than those of HA. XRD patterns showed that the peaks of both coatings matched well with standard HA patterns. FTIR spectra showed that both coatings consisted of HA crystals. The Zn-HA coating significantly improved the bone area within all threads after four and eight weeks (P<0.05), the bone to implant contact (BIC) at four weeks (P<0.05), and RTQ values after four and eight weeks (P<0.05). Conclusions: The study showed that an electrochemically deposited Zn-HA coating has potential for improving bone integration with an implant surface. PMID:23733429

  13. Stainless steel screws coated with bisphosphonates gave stronger fixation and more surrounding bone. Histomorphometry in rats.

    PubMed

    Wermelin, K; Suska, F; Tengvall, P; Thomsen, P; Aspenberg, P

    2008-02-01

    Coating of stainless steel screws with bisphosphonate in a fibrinogen matrix leads to an enhancement of the pullout strength 2 weeks after insertion in rat tibiae. This effect then increases over time until at least 8 weeks. The pullout force reflects the mechanical properties of the bone within the threads, which acts as a screw nut. The aim of the present study was to find descriptive and morphometric histological correlates to the increased pullout strength. Because the bisphosphonates are applied via the implant surface, we also measured bone to implant contact and how far away from the surface any effects could be seen. Stainless steel screws underwent one of three treatments: uncoated control, controls coated with a layer of cross-linked fibrinogen, or screws further modified with bisphosphonates covalently linked and physically adsorbed to the fibrinogen layer. At 1 (n=33) and 8 (n=27) weeks, bone to implant contact and bone area density in the threads were measured, as well as bone area density at 250 and 500 microm from the outer edge of the threads. Additionally, removal torque for each screw treatment was measured at 2 weeks (n=28). At 8 weeks, the part of the bisphosphonate screw that was located in the marrow cavity had become surrounded with bone, whereas there was almost no bone surrounding the controls. The bone area density in the threads along the entire bisphosphonate screw was increased by 40% compared with uncoated controls, and at 250 microm distance it was more than doubled. At 1 week, coated screws had less implant-bone contact, but at 8 weeks there was no difference between uncoated and bisphosphonate-coated screws. The bisphosphonate screws had 50% increased removal torque at 2 weeks compared to uncoated screws. Howship's lacunae and osteoclasts were found near the screws with bisphosphonates at 8 weeks, suggesting that some bone remodeling took place near the implant, in spite of the presence of bisphosphonates.

  14. Titania and titania-silica coatings for titanium: comparison of ectopic bone formation within cell-seeded scaffolds.

    PubMed

    Meretoja, Ville V; Tirri, Teemu; Aäritalo, Virpi; Walboomers, X Frank; Jansen, John A; Närhi, Timo O

    2007-04-01

    The aim of this study was to compare titania (TiO(2))-coated, titania-silica (TiSi)-coated, and uncoated (cpTi) titanium fiber meshes as scaffolds for bone engineering. The scaffolds were loaded with bone marrow stromal cells and implanted subcutaneously in rats. Ectopic bone formation after 1, 4, and 12 weeks of implantation was evaluated using histology and histomorphometry. After 1 week of implantation, multiple patches of unorganized mineralizing tissue were seen in all implants. The amount of this bone-like tissue clearly increased from 1 to 4 weeks. Bone apposition occurred in direct contact with coated meshes, while a thin layer of unmineralized fibrous tissue was often observed surrounding cpTi mesh fibers. After 12 weeks, the structure of bone, with bone marrow-like tissue, was further matured and mesh fibers were embedded in lamellar bone. No statistical differences in the amount of mineralized bone were observed between scaffold types at any point of time. Only TiSi scaffolds showed further increase in bone area from 4 to 12 weeks (p < 0.01). A notable difference was that the sol-gel coatings resulted in enhanced initial bone contact and distribution of bone tissue, whereas uncoated implants showed bone formation mainly in the center of the scaffolds. In conclusion, TiO(2)-based sol-gel coatings may be used in tissue engineering to gain more uniform distribution of bone throughout titanium fiber mesh scaffolds.

  15. Surface-mediated bone tissue morphogenesis from tunable nanolayered implant coatings*

    PubMed Central

    Shah, Nisarg J.; Hyder, Md. Nasim; Moskowitz, Joshua S.; Quadir, Mohiuddin A.; Morton, Stephen W.; Seeherman, Howard J.; Padera, Robert F.; Spector, Myron; Hammond, Paula T.

    2014-01-01

    The functional success of a biomedical implant critically depends on its stable bonding with the host tissue. Aseptic implant loosening accounts for over half of all joint replacement failures. Various materials, including metals and plastic, confer mechanical integrity to the device, but often these materials are not suitable for direct integration with the host tissue, which leads to implant loosening and patient morbidity. We describe a self-assembled, osteogenic, polymer-based conformal coating that promotes stable mechanical fixation of an implant in a surrogate rodent model. A single modular, polymer-based multilayered coating was deposited using a water-based layer-by-layer approach, by which each element was introduced on the surface in nanoscale layers. Osteoconductive hydroxyapatite (HAP) and osteoinductive bone morphogenetic protein 2 (BMP-2) contained within the nanostructured coating acted synergistically to induce osteoblastic differentiation of endogenous progenitor cells within the bone marrow, without indications of a foreign body response. The tuned release of BMP-2, controlled by a hydrolytically degradable poly(β-amino ester), was essential for tissue regeneration and, in the presence of HAP, the modular coating encouraged the direct deposition of highly cohesive trabecular bone on the implant surface. The bone-implant interfacial tensile strength was significantly higher than standard bone cement, did not fracture at the interface, and had long-term stability. Collectively, these results suggest that the multilayered coating system promotes biological fixation of orthopedic and dental implants to improve surgical outcomes by preventing loosening and premature failure. PMID:23803705

  16. Immunogenicity in xenogeneic scaffold generation: antigen removal vs. decellularization.

    PubMed

    Wong, Maelene L; Griffiths, Leigh G

    2014-05-01

    Decades of research have been undertaken towards the goal of tissue engineering using xenogeneic scaffolds. The primary advantages associated with use of xenogeneic tissue-derived scaffolds for in vitro development of replacement tissues and organs stem from the inherent extracellular matrix (ECM) composition and architecture. Native ECM possesses appropriate mechanical properties for physiological function of the biomaterial and signals for cell binding, growth and differentiation. Additionally, xenogeneic tissue is readily available. However, translation of xenogeneic scaffold-derived engineered tissues or organs into clinical therapies requires xenoantigenicity of the material to be adequately addressed prior to implantation. Failure to achieve this goal will result in a graft-specific host immune rejection response, jeopardizing in vivo survival of the resultant scaffold, tissue or organ. This review explores (i) the appropriateness of scaffold acellularity as an outcome measure for assessing reduction of the immunological barriers to the use of xenogeneic scaffolds for tissue engineering applications and (ii) the need for tissue engineers to strive for antigen removal during xenogeneic scaffold generation.

  17. Induction plasma sprayed Sr and Mg doped nano hydroxyapatite coatings on Ti for bone implant.

    PubMed

    Roy, Mangal; Bandyopadhyay, Amit; Bose, Susmita

    2011-11-01

    In this study, we report fabrication of strontium (Sr) and magnesium (Mg) doped hydroxyapatite (HA) coating on commercially pure titanium (Cp-Ti) substrates using inductively coupled radio frequency (RF) plasma spray. HA powder was doped with 1 wt % Sr (Sr-HA) and 1 wt % Mg (Mg-HA), heat treated at 800°C for 6 h and then used for plasma spray coating. X-ray diffraction (XRD) and Fourier transformed infrared spectroscopic (FTIR) analysis indicated that the coatings were primarily composed of phase pure crystalline HA. When compared to undoped HA coating, physical properties such as microstructure, grain size, and adhesive bond strength of the doped HA coatings did not change significantly. Microstructure of the coatings showed coherency in the structure with an average grain size of 200-280 μm HA particles, where each of the HA grains consisted of 20-30 nm sized particles. An average adhesive bond strength of 17 MPa ensured sufficient mechanical strength of the coatings. A chemistry dependent improvement in bone cell-coating interaction was noticed for doped coatings although it had minimal effect on physical properties of the coatings. In vitro cell-materials interactions using human fetal osteoblasts (hFOB) showed better cell attachment and proliferation on Sr-HA coatings compared to HA or Mg-HA coatings. Presence of Sr in the coating also stimulated hFOB cell differentiation and alkaline phosphatase (ALP) expression. Improvement in bioactivity of Sr doped HA coatings on Ti without compromising its mechanical properties makes it an excellent material of choice for coated implant.

  18. Bone formation in transforming growth factor beta-1-coated porous poly(propylene fumarate) scaffolds.

    PubMed

    Vehof, Johan W M; Fisher, John P; Dean, David; van der Waerden, Jan-Paul C M; Spauwen, Paul H M; Mikos, Antonios G; Jansen, John A

    2002-05-01

    This study determined the bone growth into pretreated poly(propylene fumarate) (PPF) scaffolds implanted into a subcritical size, rabbit cranial defect. PPF scaffolds were constructed by using a photocrosslinking-porogen leaching technique. These scaffolds were then either prewetted (PPF-Pw), treated with RF glow-discharge (PPF-Gd), coated with fibronectin (PPF-Fn), or coated with rhTGF-beta1 (PPF-TGF-beta1). One of each scaffold type was then placed into the cranium of nine rabbits. The rabbits were sacrificed after 8 weeks, and the scaffolds were retrieved for histological analysis. The most bone formation was present in the PPF-TGF-beta1 implants; the newly formed bone had a trabecular appearance together with bone marrow-like tissue. Little or no bone formation was observed in implants without rhTGF-beta1. These histological findings were confirmed by image analysis. Bone surface area, bone area percentage, pore fill percentage, and pore area percentage were significantly higher in the rhTGF-beta1-coated implants than in the noncoated implants. No statistical difference was seen between the PPF-Fn, PPF-Pw, or PPF-Gd scaffolds for these parameters. Quadruple fluorochrome labeling showed that in PPF-TGF-beta1 implants bone formation mainly started in the interior of a pore and proceeded toward the scaffold. We conclude that (a) PPF-TGF-beta1 scaffolds can indeed adequately induce bone formation in porous PPF, and (b) PPF scaffolds prepared by the photocrosslinking-porogen leaching technique are good candidates for the creation of bone graft substitutes.

  19. Clinical, Radiographic, and Histologic Evaluation of Maxillary Sinus Lift Procedure Using a Highly Purified Xenogenic Graft (Laddec®)

    PubMed Central

    Belleggia, Fabrizio; Ippoliti, Stefano; DeVilliers, Patrica; Stefanelli, Luigi Vito; Di Carlo, Stefano; Pompa, Giorgio

    2016-01-01

    ABSTRACT Objectives The aim of this study was to evaluate the clinical, radiographic and histologic results when a highly purified xenogenic bone (Laddec®) was used as grafting material in maxillary sinuses. Material and Methods In fifteen patients requiring unilateral maxillary sinus augmentation, the grafting procedure was performed with Laddec®. Forty-two implants were installed after a 6 month healing period. The height of the augmented sinus was measured radiographically immediately after augmentation and postoperatively up to 36 months. At the time of implant placement, a bone core was harvested in each patient for histological examination. Results The cumulative implant survival rate was 97.6%. The original height was 3.65 (SD 0.7) mm and the augmented sinus height was 13.8 (SD 1.4) mm after the surgery. The reduced height of grafted xenogenic material (RDL) at the implant insertion was 0.83 (SD 0.38) mm, and at the final postoperative visit was 0.91 (SD 0.25) mm, showing no significant correlation with the follow-up periods by Spearman’s test (P = 0.118). In addition, no significant difference in the RDL was observed according to the site of implantation (P = 0.682). The mean implant marginal bone loss was 0.38 (SD 0.24) mm. Histological analysis showed the bone cores were composed of 64.72 (SD 3.44)% newly formed bone, 17.41 (SD 2.02)% connective tissue, 16.93 (SD 2.83)% residual graft particles, and 0.94 (SD 0.11)% inflammatory cells. Conclusions According to our data, the highly purified xenogenic bone (Laddec®), used as graft material in the sinus lift procedure, may create adequate bone volume, and appropriate osseointegration of dental implants. PMID:27099697

  20. PCL-coated hydroxyapatite scaffold derived from cuttlefish bone: morphology, mechanical properties and bioactivity.

    PubMed

    Milovac, Dajana; Gallego Ferrer, Gloria; Ivankovic, Marica; Ivankovic, Hrvoje

    2014-01-01

    In the present study, poly(ε-caprolactone)-coated hydroxyapatite scaffold derived from cuttlefish bone was prepared. Hydrothermal transformation of aragonitic cuttlefish bone into hydroxyapatite (HAp) was performed at 200°C retaining the cuttlebone architecture. The HAp scaffold was coated with a poly(ε-caprolactone) (PCL) using vacuum impregnation technique. The compositional and morphological properties of HAp and PCL-coated HAp scaffolds were studied by means of X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis. Bioactivity was tested by immersion in Hank's balanced salt solution (HBSS) and mechanical tests were performed at compression. The results showed that PCL-coated HAp (HAp/PCL) scaffold resulted in a material with improved mechanical properties that keep the original interconnected porous structure indispensable for tissue growth and vascularization. The compressive strength (0.88MPa) and the elastic modulus (15.5MPa) are within the lower range of properties reported for human trabecular bones. The in vitro mineralization of calcium phosphate (CP) that produces the bone-like apatite was observed on both the pure HAp scaffold and the HAp/PCL composite scaffold. The prepared bioactive scaffold with enhanced mechanical properties is a good candidate for bone tissue engineering applications.

  1. Antibacterial efficacy of a new gentamicin-coating for cementless prostheses compared to gentamicin-loaded bone cement.

    PubMed

    Neut, Daniëlle; Dijkstra, René J B; Thompson, Jonathan I; van der Mei, Henny C; Busscher, Henk J

    2011-11-01

    Cementless prostheses are increasingly popular but require alternative prophylactic measures than the use of antibiotic-loaded bone cements. Here, we determine the 24-h growth inhibition of gentamicin-releasing coatings from grit-blasted and porous-coated titanium alloys, and compare their antibacterial efficacies and gentamicin release-profiles to those of a commercially available gentamicin-loaded bone cement. Antibacterial efficacy increased with increasing doses of gentamicin in the coating and loading with 1.0 and 0.1 mg gentamicin/cm(2) on both grit-blasted and porous-coated samples yielded comparable efficacy to gentamicin-loaded bone cement. The coating had a higher burst release than bone cement, and also inhibited growth of gentamicin-resistant strains. Antibacterial efficacy of the gentamicin coatings disappeared after 4 days, while gentamicin-loaded bone cement exhibited efficacy over at least 7 days. Shut-down after 4 days of gentamicin-release from coatings is advantageous over the low-dosage tail-release from bone cements, as it minimizing risk of inducing antibiotic-resistant strains. Both gentamicin-loaded cement discs and gentamicin-coated titanium coupons were able to kill gentamicin-sensitive and -resistant bacteria in a simulated prothesis-related interfacial gap. In conclusion, the gentamicin coating provided similar antibacterial properties to those seen by gentamicin-loaded bone cement, implying protection of a prosthesis from being colonized by peri-operatively introduced bacteria in cementless total joint arthroplasty.

  2. Processing of hydroxylapatite coatings on titanium alloy bone prostheses

    DOEpatents

    Nastasi, Michael A.; Levine, Timothy E.; Mayer, James W.; Pizziconi, Vincent B.

    1998-01-01

    Processing of hydroxylapatite sol-gel films on titanium alloy bone prostheses. A method utilizing non-line-of-sight ion beam implantation and/or rapid thermal processing to provide improved bonding of layers of hydroxylapatite to titanium alloy substrates while encouraging bone ingrowth into the hydroxylapatite layers located away from the substrate, is described for the fabrication of prostheses. The first layer of hydroxylapatite is mixed into the substrate by the ions or rapidly thermally annealed, while subsequent layers are heat treated or densified using ion implantation to form layers of decreasing density and larger crystallization, with the outermost layers being suitable for bone ingrowth.

  3. Processing of hydroxylapatite coatings on titanium alloy bone prostheses

    DOEpatents

    Nastasi, M.A.; Levine, T.E.; Mayer, J.W.; Pizziconi, V.B.

    1998-10-06

    Processing of hydroxylapatite sol-gel films on titanium alloy bone prostheses. A method utilizing non-line-of-sight ion beam implantation and/or rapid thermal processing to provide improved bonding of layers of hydroxylapatite to titanium alloy substrates while encouraging bone ingrowth into the hydroxylapatite layers located away from the substrate, is described for the fabrication of prostheses. The first layer of hydroxylapatite is mixed into the substrate by the ions or rapidly thermally annealed, while subsequent layers are heat treated or densified using ion implantation to form layers of decreasing density and larger crystallization, with the outermost layers being suitable for bone ingrowth.

  4. Bioactive lipid coating of bone allografts directs engraftment and fate determination of bone marrow-derived cells in rat GFP chimeras.

    PubMed

    Das, Anusuya; Segar, Claire E; Chu, Yihsuan; Wang, Tiffany W; Lin, Yong; Yang, Chunxi; Du, Xeujun; Ogle, Roy C; Cui, Quanjun; Botchwey, Edward A

    2015-09-01

    Bone grafting procedures are performed to treat wounds incurred during wartime trauma, accidents, and tumor resections. Endogenous mechanisms of repair are often insufficient to ensure integration between host and donor bone and subsequent restoration of function. We investigated the role that bone marrow-derived cells play in bone regeneration and sought to increase their contributions by functionalizing bone allografts with bioactive lipid coatings. Polymer-coated allografts were used to locally deliver the immunomodulatory small molecule FTY720 in tibial defects created in rat bone marrow chimeras containing genetically-labeled bone marrow for monitoring cell origin and fate. Donor bone marrow contributed significantly to both myeloid and osteogenic cells in remodeling tissue surrounding allografts. FTY720 coatings altered the phenotype of immune cells two weeks post-injury, which was associated with increased vascularization and bone formation surrounding allografts. Consequently, degradable polymer coating strategies that deliver small molecule growth factors such as FTY720 represent a novel therapeutic strategy for harnessing endogenous bone marrow-derived progenitors and enhancing healing in load-bearing bone defects.

  5. Porous biomorphic silicon carbide ceramics coated with hydroxyapatite as prospective materials for bone implants.

    PubMed

    Gryshkov, Oleksandr; Klyui, Nickolai I; Temchenko, Volodymyr P; Kyselov, Vitalii S; Chatterjee, Anamika; Belyaev, Alexander E; Lauterboeck, Lothar; Iarmolenko, Dmytro; Glasmacher, Birgit

    2016-11-01

    Porous and cytocompatible silicon carbide (SiC) ceramics derived from wood precursors and coated with bioactive hydroxyapatite (HA) and HA-zirconium dioxide (HA/ZrO2) composite are materials with promising application in engineering of bone implants due to their excellent mechanical and structural properties. Biomorphic SiC ceramics have been synthesized from wood (Hornbeam, Sapele, Tilia and Pear) using a forced impregnation method. The SiC ceramics have been coated with bioactive HA and HA/ZrO2 using effective gas detonation deposition approach (GDD). The surface morphology and cytotoxicity of SiC ceramics as well as phase composition and crystallinity of deposited coatings were analyzed. It has been shown that the porosity and pore size of SiC ceramics depend on initial wood source. The XRD and FTIR studies revealed the preservation of crystal structure and phase composition of in the HA coating, while addition of ZrO2 to the initial HA powder resulted in significant decomposition of the final HA/ZrO2 coating and formation of other calcium phosphate phases. In turn, NIH 3T3 cells cultured in medium exposed to coated and uncoated SiC ceramics showed high re-cultivation efficiency as well as metabolic activity. The recultivation efficiency of cells was the highest for HA-coated ceramics, whereas HA/ZrO2 coating improved the recultivation efficiency of cells as compared to uncoated SiC ceramics. The GDD method allowed generating homogeneous HA coatings with no change in calcium to phosphorus ratio. In summary, porous and cytocompatible bio-SiC ceramics with bioactive coatings show a great promise in construction of light, robust, inexpensive and patient-specific bone implants for clinical application.

  6. Antibacterial chitosan coating on nano-hydroxyapatite/polyamide66 porous bone scaffold for drug delivery.

    PubMed

    Huang, Di; Zuo, Yi; Zou, Qin; Zhang, Li; Li, Jidong; Cheng, Lin; Shen, Juan; Li, Yubao

    2011-01-01

    This study describes a new drug-loaded coating scaffold applied in infection therapy during bone regeneration. Chitosan (CS) containing antibacterial berberine was coated on a nano-hydroxyapatite/polyamide66 (n-HA/PA66) scaffold to realize bone regeneration together with antimicrobial properties. The porous scaffold was fabricated using the phase-inversion method with a porosity of about 84% and macropore size of 400-600 μm. The morphology, mechanical properties and drug-release behavior were investigated at different ratios of chitosan to berberine. The results show that the elastic modulus and compressive strength of the coated scaffolds were improved to 35.4 MPa and 1.7 MPa, respectively, about 7 times and 3 times higher than the uncoated scaffolds. After a burst release of berberine within the first 3 h in PBS solution, a continuous berberine release can last 150 h, which is highly dependent on the coating concentration and suitable for antibacterial requirement of orthopaedic surgery. The bactericidal test confirms a strong antibiotic effect of the delivery system and the minimum inhibitory concentration of the drug is 0.02 mg/ml. Moreover, in vitro biological evaluation demonstrates that the coating scaffolds act as a good matrix for MG63 adhesion, crawl, growth and proliferation, suggesting that the antibacterial delivery system has no cytotoxicity. We expect the drug-delivery system to have a potential application in bone regeneration or defect repair.

  7. Acid-etched microtexture for enhancement of bone growth into porous-coated implants.

    PubMed

    Hacking, S A; Harvey, E J; Tanzer, M; Krygier, J J; Bobyn, J D

    2003-11-01

    We designed an in vivo study to determine if the superimposition of a microtexture on the surface of sintered titanium beads affected the extent of bone ingrowth. Cylindrical titanium intramedullary implants were coated with titanium beads to form a porous finish using commercial sintering techniques. A control group of implants was left in the as-sintered condition. The test group was etched in a boiling acidic solution to create an irregular surface over the entire porous coating. Six experimental dogs underwent simultaneous bilateral femoral intramedullary implantation of a control implant and an acid etched implant. At 12 weeks, the implants were harvested in situ and the femora processed for undecalcified, histological examination. Eight transverse serial sections for each implant were analysed by backscattered electron microscopy and the extent of bone ingrowth was quantified by computer-aided image analysis. The extent of bone ingrowth into the control implants was 15.8% while the extent of bone ingrowth into the etched implants was 25.3%, a difference of 60% that was statistically significant. These results are consistent with other research that documents the positive effect of microtextured surfaces on bone formation at an implant surface. The acid etching process developed for this study represents a simple method for enhancing the potential of commonly available porous coatings for biological fixation.

  8. Adaptive growth factor delivery from a polyelectrolyte coating promotes synergistic bone tissue repair and reconstruction

    PubMed Central

    Shah, Nisarg J.; Hyder, Md. Nasim; Quadir, Mohiuddin A.; Dorval Courchesne, Noémie-Manuelle; Seeherman, Howard J.; Nevins, Myron; Spector, Myron; Hammond, Paula T.

    2014-01-01

    Traumatic wounds and congenital defects that require large-scale bone tissue repair have few successful clinical therapies, particularly for craniomaxillofacial defects. Although bioactive materials have demonstrated alternative approaches to tissue repair, an optimized materials system for reproducible, safe, and targeted repair remains elusive. We hypothesized that controlled, rapid bone formation in large, critical-size defects could be induced by simultaneously delivering multiple biological growth factors to the site of the wound. Here, we report an approach for bone repair using a polyelectrolye multilayer coating carrying as little as 200 ng of bone morphogenetic protein-2 and platelet-derived growth factor-BB that were eluted over readily adapted time scales to induce rapid bone repair. Based on electrostatic interactions between the polymer multilayers and growth factors alone, we sustained mitogenic and osteogenic signals with these growth factors in an easily tunable and controlled manner to direct endogenous cell function. To prove the role of this adaptive release system, we applied the polyelectrolyte coating on a well-studied biodegradable poly(lactic-co-glycolic acid) support membrane. The released growth factors directed cellular processes to induce bone repair in a critical-size rat calvaria model. The released growth factors promoted local bone formation that bridged a critical-size defect in the calvaria as early as 2 wk after implantation. Mature, mechanically competent bone regenerated the native calvaria form. Such an approach could be clinically useful and has significant benefits as a synthetic, off-the-shelf, cell-free option for bone tissue repair and restoration. PMID:25136093

  9. Bioactive ceramic coating on orthopedic implants for enhanced bone tissue integration

    NASA Astrophysics Data System (ADS)

    Aniket

    Tissue integration between bone and orthopedic implant is essential for implant fixation and longevity. An immunological response leads to fibrous encapsulation of metallic implants leading to implant instability and failure. Bioactive ceramics have the ability to directly bond to bone; however, they have limited mechanical strength for load bearing applications. Coating bioactive ceramics on metallic implant offers the exciting opportunity to enhance bone formation without compromising the mechanical strength of the implant. In the present study, we have developed a novel bioactive silica-calcium phosphate nanocomposite (SCPC) coating on medical grade Ti-6Al-4V orthopedic implant using electrophoretic deposition (EPD) and evaluated bone tissue response to the coated implant at the cellular level. The effect of SCPC composition and suspending medium pH on the zeta potential of three different SCPC formulations; SCPC25, SCPC50 and SCPC75 were analyzed. The average zeta potential of SCPC50 in pure ethanol was more negative than that of SCPC25 or SCPC75; however the difference was not statistically significant. Ti-6Al-4V discs were passivated, coated with SCPC50 (200 nm - 10 mum) and thermally treated at 600 - 800 ºC to produce a coating thickness in the range of 43.1 +/- 5.7 to 30.1 +/- 4.6 μm. After treatment at 600, 700 and 800 ºC, the adhesion strength at the SCPC50/Ti-6Al-4V interface was 42.6 +/- 3.6, 44.7 +/- 8.7 and 47.2 +/- 4.3 MPa, respectively. XRD analyses of SCPC50 before and after EPD coating indicated no change in the crystallinity of the material. Fracture surface analyses showed that failure occurred within the ceramic layer or at the ceramic/polymer interface; however, the ceramic/metal interface was intact in all samples. The adhesion strength of SCPC50-coated substrates after immersion in PBS for 2 days (11.7 +/- 3.9 MPa) was higher than that measured on commercially available hydroxyapatite (HA) coated substrates (5.5 +/- 2.7 MPa), although the

  10. Effect of coating Straumann Bone Ceramic with Emdogain on mesenchymal stromal cell hard tissue formation.

    PubMed

    Mrozik, Krzysztof Marek; Gronthos, Stan; Menicanin, Danijela; Marino, Victor; Bartold, P Mark

    2012-06-01

    Periodontal tissue engineering requires a suitable biocompatible scaffold, cells with regenerative capacity, and instructional molecules. In this study, we investigated the capacity of Straumann Bone Ceramic coated with Straumann Emdogain, a clinical preparation of enamel matrix protein (EMP), to aid in hard tissue formation by post-natal mesenchymal stromal cells (MSCs) including bone marrow stromal cells (BMSCs) and periodontal ligament fibroblasts (PDLFs). MSCs were isolated and ex vivo-expanded from human bone marrow and periodontal ligament and, in culture, allowed to attach to Bone Ceramic in the presence or absence of Emdogain. Gene expression of bone-related proteins was investigated by real time RT-PCR for 72 h, and ectopic bone formation was assessed histologically in subcutaneous implants of Bone Ceramic containing MSCs with or without Emdogain in NOD/SCID mice. Alkaline phosphatase activity was also assessed in vitro, in the presence or absence of Emdogain. Collagen-I mRNA was up-regulated in both MSC populations over the 72-h time course with Emdogain. Expression of BMP-2 and the osteogenic transcription factor Cbfa-1 showed early stimulation in both MSC types after 24 h. In contrast, expression of BMP-4 was consistently down-regulated in both MSC types with Emdogain. Up-regulation of osteopontin and periostin mRNA was restricted to BMSCs, while higher levels of bone sialoprotein-II were observed in PDLFs with Emdogain. Furthermore, alkaline phosphatase activity levels were reduced in both BMSCs and PDLFs in the presence of Emdogain. Very little evidence was found for ectopic bone formation following subcutaneous implantation of MSCs with Emdogain-coated or -uncoated Bone Ceramic in NOD/SCID mice. The early up-regulation of several important bone-related genes suggests that Emdogain may have a significant stimulatory effect in the commitment of mesenchymal cells to osteogenic differentiation in vitro. While Emdogain inhibited AP activity and appeared

  11. Hydroxyapatite nanocrystals functionalized with alendronate as bioactive components for bone implant coatings to decrease osteoclastic activity

    NASA Astrophysics Data System (ADS)

    Bosco, Ruggero; Iafisco, Michele; Tampieri, Anna; Jansen, John A.; Leeuwenburgh, Sander C. G.; van den Beucken, Jeroen J. J. P.

    2015-02-01

    The integration of bone implants within native bone tissue depends on periprosthetic bone quality, which is severely decreased in osteoporotic patients. In this work, we have synthesized bone-like hydroxyapatite nanocrystals (nHA) using an acid-base neutralization reaction and analysed their physicochemical properties. Subsequently, we have functionalized the nHA with alendronate (nHAALE), a well-known bisphosphonate drug used for the treatment of osteoporosis. An in vitro osteoclastogenesis test was carried out to evaluate the effect of nHAALE on the formation of osteoclast-like cells from monocytic precursor cells (i.e. RAW264.7 cell line) showing that nHAALE significantly promoted apoptosis of osteoclast-like cells. Subsequently, nHA and nHAALE were deposited on titanium disks using electrospray deposition (ESD), for which characterisation of the deposited coatings confirmed the presence of alendronate in nHAALE coatings with nanoscale thickness of about 700 nm. These results indicate that alendronate linked to hydroxyapatite nanocrystals has therapeutic potential and nHAALE can be considered as an appealing coating constituent material for orthopaedic and oral implants for application in osteoporotic patients.

  12. Coating cortical bone allografts with periosteum-mimetic scaffolds made of chitosan, trimethyl chitosan, and heparin.

    PubMed

    Romero, Raimundo; Chubb, Laura; Travers, John K; Gonzales, Timothy R; Ehrhart, Nicole P; Kipper, Matt J

    2015-05-20

    Bone allografts have very limited healing leading to high rates of failure from non-union, fracture, and infection. The limited healing of bone allografts is due in large part to devitalization and removal of the periosteum, which removes osteogenic cells and osteoinductive signals. Here we report techniques for directly coating cortical bone with tissue scaffolds, and evaluate the scaffolds' capacity to support osteoprogenitor cells. Three types of coatings are investigated: N,N,N-trimethyl chitosan-heparin polyelectrolyte multilayers, freeze-dried porous chitosan foam coatings, and electrospun chitosan nanofibers. The freeze-dried and electrospun scaffolds are also further modified with polyelectrolyte multilayers. All of the scaffolds are durable to subsequent aqueous processing, and are cytocompatible with adipose-derived stem cells. Alkaline phosphatase and receptor activator of nuclear factor kappa-B ligand expression at days 7 and 21 suggest that these scaffolds support an osteoprogenitor phenotype. These scaffolds could serve as periosteum mimics, deliver osteoprogenitor cells, and improve bone allograft healing.

  13. Porous tantalum coatings prepared by vacuum plasma spraying enhance bmscs osteogenic differentiation and bone regeneration in vitro and in vivo.

    PubMed

    Tang, Ze; Xie, Youtao; Yang, Fei; Huang, Yan; Wang, Chuandong; Dai, Kerong; Zheng, Xuebin; Zhang, Xiaoling

    2013-01-01

    Tantalum, as a potential metallic implant biomaterial, is attracting more and more attention because of its excellent anticorrosion and biocompatibility. However, its significantly high elastic modulus and large mechanical incompatibility with bone tissue make it unsuitable for load-bearing implants. In this study, porous tantalum coatings were first successfully fabricated on titanium substrates by vacuum plasma spraying (VPS), which would exert the excellent biocompatibility of tantalum and alleviate the elastic modulus of tantalum for bone tissue. We evaluated cytocompatibility and osteogenesis activity of the porous tantalum coatings using human bone marrow stromal cells (hBMSCs) and its ability to repair rabbit femur bone defects. The morphology and actin cytoskeletons of hBMSCs were observed via electron microscopy and confocal, and the cell viability, proliferation and osteogenic differentiation potential of hBMSCs were examined quantitatively by PrestoBlue assay, Ki67 immunofluorescence assay, real-time PCR technology and ALP staining. For in vivo detection, the repaired femur were evaluated by histomorphology and double fluorescence labeling 3 months postoperation. Porous tantalum coating surfaces promoted hBMSCs adhesion, proliferation, osteogenesis activity and had better osseointegration and faster new bone formation rate than titanium coating control. Our observation suggested that the porous tantalum coatings had good biocompatibility and could enhance osseoinductivity in vitro and promote new bone formation in vivo. The porous tantalum coatings prepared by VPS is a promising strategy for bone regeneration.

  14. Porous Tantalum Coatings Prepared by Vacuum Plasma Spraying Enhance BMSCs Osteogenic Differentiation and Bone Regeneration In Vitro and In Vivo

    PubMed Central

    Tang, Ze; Xie, Youtao; Yang, Fei; Huang, Yan; Wang, Chuandong; Dai, Kerong; Zheng, Xuebin; Zhang, Xiaoling

    2013-01-01

    Tantalum, as a potential metallic implant biomaterial, is attracting more and more attention because of its excellent anticorrosion and biocompatibility. However, its significantly high elastic modulus and large mechanical incompatibility with bone tissue make it unsuitable for load-bearing implants. In this study, porous tantalum coatings were first successfully fabricated on titanium substrates by vacuum plasma spraying (VPS), which would exert the excellent biocompatibility of tantalum and alleviate the elastic modulus of tantalum for bone tissue. We evaluated cytocompatibility and osteogenesis activity of the porous tantalum coatings using human bone marrow stromal cells (hBMSCs) and its ability to repair rabbit femur bone defects. The morphology and actin cytoskeletons of hBMSCs were observed via electron microscopy and confocal, and the cell viability, proliferation and osteogenic differentiation potential of hBMSCs were examined quantitatively by PrestoBlue assay, Ki67 immunofluorescence assay, real-time PCR technology and ALP staining. For in vivo detection, the repaired femur were evaluated by histomorphology and double fluorescence labeling 3 months postoperation. Porous tantalum coating surfaces promoted hBMSCs adhesion, proliferation, osteogenesis activity and had better osseointegration and faster new bone formation rate than titanium coating control. Our observation suggested that the porous tantalum coatings had good biocompatibility and could enhance osseoinductivity in vitro and promote new bone formation in vivo. The porous tantalum coatings prepared by VPS is a promising strategy for bone regeneration. PMID:23776648

  15. Biodegradation rate of shellac coated bovine hydroxyapatite for bone filler material

    NASA Astrophysics Data System (ADS)

    Triyono, Joko; Triyono, Susilowati, Endang; Murdiyantara, Suci Anindya

    2016-03-01

    This work reports on the effect of shellac coated hydroxyapatite (HA) on the biodegradation rate. The HA was processed from bovine bone. Shellac was derived from the resinous secretion of the lac insect. The aims of the addition of shellac solution is to know how the biodegradation rate material in the Phosphate Buffered Saline (PBS) solution. The four different of shellac solutions (2,5%; 5%; 7,5%; and 10% weight) coated HA scaffoldand one ratio as a control. It was concluded that the ability of biodegradation rate a materialwas not influenced by the ratio of shellac. All materials were biodegradedwhen they were soaked in PBS solution.

  16. Enhancement of osteogenesis and biodegradation control by brushite coating on Mg-Nd-Zn-Zr alloy for mandibular bone repair.

    PubMed

    Guan, Xingmin; Xiong, Meiping; Zeng, Feiyue; Xu, Bin; Yang, Lingdi; Guo, Han; Niu, Jialin; Zhang, Jian; Chen, Chenxin; Pei, Jia; Huang, Hua; Yuan, Guangyin

    2014-12-10

    To diminish incongruity between bone regeneration and biodegradation of implant magnesium alloy applied for mandibular bone repair, a brushite coating was deposited on a matrix of a Mg-Nd-Zn-Zr (hereafter, denoted as JDBM) alloy to control the degradation rate of the implant and enhance osteogenesis of the mandible bone. Both in vitro and in vivo evaluations were carried out in the present work. Viability and adhesion assays of rabbit bone marrow mesenchyal stem cells (rBM-MSCs) were applied to determine the biocompatibility of a brushite-coated JDBM alloy. Osteogenic gene expression was characterized by quantitative real-time polymerase chain reaction (RT-PCR). Brushite-coated JDBM screws were implanted into mandible bones of rabbits for 1, 4, and 7 months, respectively, using 316L stainless steel screws as a control group. In vivo biodegradation rate was determined by synchrotron radiation X-ray microtomography, and osteogenesis was observed and evaluated using Van Gieson's picric acid-fuchsin. Both the naked JDBM and brushite-coated JDBM samples revealed adequate biosafety and biocompatibility as bone repair substitutes. In vitro results showed that brushite-coated JDBM considerably induced osteogenic differentiation of rBM-MSCs. And in vivo experiments indicated that brushite-coated JDBM screws presented advantages in osteoconductivity and osteogenesis of mandible bone of rabbits. Degradation rate was suppressed at a lower level at the initial stage of implantation when new bone tissue formed. Brushite, which can enhance oeteogenesis and partly control the degradation rate of an implant, is an appropriate coating for JDBM alloys used for mandibular repair. The Mg-Nd-Zn-Zr alloy with brushite coating possesses great potential for clinical applications for mandibular repair.

  17. Direct Laser Processing of Tantalum Coating on Titanium for Bone Replacement Structures

    PubMed Central

    Balla, Vamsi Krishna; Banerjee, Shashwat; Bose, Susmita; Bandyopadhyay, Amit

    2010-01-01

    Recently, tantalum is gaining more attention as a new metallic biomaterial as it has been shown to be bioactive and biologically bond to the bone. However, relatively high cost of manufacture and inability to produce a modular all tantalum implant has limited'its widespread acceptance. In this study, we have successfully deposited Ta coating on Ti using Laser Engineered Net Shaping (LENS™) to enhance osseointegration properties. In vitro biocompatibility study, using human osteoblast cell line hFOB, showed excellent cellular adherence and growth with abundant extracellular matrix formation on Ta coating surface compare to Ti surface. Six times higher living cell density was observed on Ta coating than on Ti control surface during MMT assay. High surface energy and wettability of Ta surface were observed to contribute to its significantly better cell-materials interactions. Also, these dense Ta coatings do not suffer from low fatigue resistance due to the absence of porosity and sharp interface between the coating and the substrate, which is a major concern for porous coatings used for enhanced/early biological fixation. PMID:19931654

  18. In Vitro and In Vivo Evaluation of Zinc-Modified Ca–Si-Based Ceramic Coating for Bone Implants

    PubMed Central

    Zheng, Xuebin; He, Dannong; Ye, Xiaojian; Wang, Meiyan

    2013-01-01

    The host response to calcium silicate ceramic coatings is not always favorable because of their high dissolution rates, leading to high pH within the surrounding physiological environment. Recently, a zinc-incorporated calcium silicate-based ceramic Ca2ZnSi2O7 coating, developed on a Ti-6Al-4V substrate using plasma-spray technology, was found to exhibit improved chemical stability and biocompatibility. This study aimed to investigate and compare the in vitro response of osteoblastic MC3T3-E1 cells cultured on Ca2ZnSi2O7 coating, CaSiO3 coating, and uncoated Ti-6Al-4V titanium control at cellular and molecular level. Our results showed Ca2ZnSi2O7 coating enhanced MC3T3-E1 cell attachment, proliferation, and differentiation compared to CaSiO3 coating and control. In addition, Ca2ZnSi2O7 coating increased mRNA levels of osteoblast-related genes (alkaline phosphatase, procollagen α1(I), osteocalcin), insulin-like growth factor-I (IGF-I), and transforming growth factor-β1 (TGF-β1). The in vivo osteoconductive properties of Ca2ZnSi2O7 coating, compared to CaSiO3 coating and control, was investigated using a rabbit femur defect model. Histological and histomorphometrical analysis demonstrated new bone formation in direct contact with the Ca2ZnSi2O7 coating surface in absence of fibrous tissue and higher bone-implant contact rate (BIC) in the Ca2ZnSi2O7 coating group, indicating better biocompatibility and faster osseointegration than CaSiO3 coated and control implants. These results indicate Ca2ZnSi2O7 coated implants have applications in bone tissue regeneration, since they are biocompatible and able to osseointegrate with host bone. PMID:23483914

  19. Bone-like apatite coating on functionalized poly(etheretherketone) surface via tailored silanization layers technique.

    PubMed

    Zheng, Yanyan; Xiong, Chengdong; Zhang, Shenglan; Li, Xiaoyu; Zhang, Lifang

    2015-10-01

    Poly(etheretherketone) (PEEK) is a rigid semi-crystalline polymer with outstanding mechanical properties, bone-like stiffness and suitable biocompatibility that has attracted much interest as a biomaterial for orthopedic and dental implants. However, the bio-inert surface of PEEK limits its biomedical applications when direct osteointegration between the implants and the host tissue is desired. In this work, -PO4H2, -COOH and -OH groups were introduced on the PEEK surface by further chemical treatments of the vinyl-terminated silanization layers formed on the hydroxylation-pretreated PEEK surface. Both the surface-functionalized and pristine specimens were characterized by X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and water contact angle measurements. When placed in 1.5 strength simulated body fluid (SBF) solution, apatite was observed to form uniformly on the functionalized PEEK surface and firmly attach to the substrate. The characterized results demonstrated that the coating was constituted by poorly crystallized bone-like apatite and the effect of surface functional groups on coating formation was also discussed in detail. In addition, in vitro biocompatibility of PEEK, in terms of pre-osteoblast cell (MC3T3-E1) attachment, spreading and proliferation, was remarkably enhanced by the bone-like apatite coating. Thus, this study provides a method to enhance the bioactivity of PEEK and expand its applications in orthopedic and dental implants.

  20. Effect of Nanoparticle Incorporation and Surface Coating on Mechanical Properties of Bone Scaffolds: A Brief Review

    PubMed Central

    Corona-Gomez, Jesus; Chen, Xiongbiao; Yang, Qiaoqin

    2016-01-01

    Mechanical properties of a scaffold play an important role in its in vivo performance in bone tissue engineering, due to the fact that implanted scaffolds are typically subjected to stress including compression, tension, torsion, and shearing. Unfortunately, not all the materials used to fabricate scaffolds are strong enough to mimic native bones. Extensive research has been conducted in order to increase scaffold strength and mechanical performance by incorporating nanoparticles and/or coatings. An incredible improvement has been achieved; and some outstanding examples are the usage of nanodiamond, hydroxyapatite, bioactive glass particles, SiO2, MgO, and silver nanoparticles. This review paper aims to present the results, to summarize significant findings, and to give perspective for future work, which could be beneficial to future bone tissue engineering. PMID:27420104

  1. Improvement of osteogenic potential of biphasic calcium phosphate bone substitute coated with synthetic cell binding peptide sequences

    PubMed Central

    Choi, Hyunmin; Park, Nho-Jae; Jamiyandorj, Otgonbold; Hong, Min-Ho; Oh, Seunghan; Park, Young-Bum

    2012-01-01

    Purpose The aim of this study was to evaluate the improvement of osteogenic potential of biphasic calcium phosphate (BCP) bone substitute coated with synthetic cell-binding peptide sequences in a standardized rabbit sinus model. Methods Standardized 6-mm diameter defects were created bilaterally on the maxillary sinus of ten male New Zealand white rabbits, receiving BCP bone substitute coated with synthetic cell binding peptide sequences on one side (experimental group) and BCP bone substitute without coating (control group) on the other side. Histologic and histomorphometric analysis of bone formation was carried out after a healing period of 4 or 8 weeks. Results Histological analysis revealed signs of new bone formation in both experimental groups (4- and 8-week healing groups) with a statistically significant increase in bone formation in the 4-week healing group compared to the control group. However, no statistically significant difference in bone formation was found between the 8-week healing group and the control group. Conclusions This study found that BCP bone substitute coated with synthetic cell-binding peptide sequences enhanced osteoinductive potential in a standardized rabbit sinus model and its effectiveness was greater in the 4-week healing group than in the 8-week healing group. PMID:23185697

  2. Polyether ether ketone implants achieve increased bone fusion when coated with nano-sized hydroxyapatite: a histomorphometric study in rabbit bone.

    PubMed

    Johansson, Pär; Jimbo, Ryo; Naito, Yoshihito; Kjellin, Per; Currie, Fredrik; Wennerberg, Ann

    2016-01-01

    Polyether ether ketone (PEEK) possesses excellent mechanical properties similar to those of human bone and is considered the best alternative material other than titanium for orthopedic spine and trauma implants. However, the deficient osteogenic properties and the bioinertness of PEEK limit its fields of application. The aim of this study was to limit these drawbacks by coating the surface of PEEK with nano-scaled hydroxyapatite (HA) minerals. In the study, the biological response to PEEK, with and without HA coating, was investigated. Twenty-four screw-like and apically perforated implants in the rabbit femur were histologically evaluated at 3 weeks and 12 weeks after surgery. Twelve of the 24 implants were HA coated (test), and the remaining 12 served as uncoated PEEK controls. At 3 weeks and 12 weeks, the mean bone-implant contact was higher for test compared to control (P<0.05). The bone area inside the threads was comparable in the two groups, but the perforating hole showed more bone area for the HA-coated implants at both healing points (P<0.01). With these results, we conclude that nano-sized HA coating on PEEK implants significantly improved the osteogenic properties, and in a clinical situation this material composition may serve as an implant where a rapid bone fusion is essential.

  3. Tantalum coating of porous carbon scaffold supplemented with autologous bone marrow stromal stem cells for bone regeneration in vitro and in vivo.

    PubMed

    Wei, Xiaowei; Zhao, Dewei; Wang, Benjie; Wang, Wei; Kang, Kai; Xie, Hui; Liu, Baoyi; Zhang, Xiuzhi; Zhang, Jinsong; Yang, Zhenming

    2016-03-01

    Porous tantalum metal with low elastic modulus is similar to cancellous bone. Reticulated vitreous carbon (RVC) can provide three-dimensional pore structure and serves as the ideal scaffold of tantalum coating. In this study, the biocompatibility of domestic porous tantalum was first successfully tested with bone marrow stromal stem cells (BMSCs) in vitro and for bone tissue repair in vivo. We evaluated cytotoxicity of RVC scaffold and tantalum coating using BMSCs. The morphology, adhesion, and proliferation of BMSCs were observed via laser scanning confocal microscope and scanning electron microscopy. In addition, porous tantalum rods with or without autologous BMSCs were implanted on hind legs in dogs, respectively. The osteogenic potential was observed by hard tissue slice examination. At three weeks and six weeks following implantation, new osteoblasts and new bone were observed at the tantalum-host bone interface and pores. At 12 weeks postporous tantalum with autologous BMSCs implantation, regenerated trabecular equivalent to mature bone was found in the pore of tantalum rods. Our results suggested that domestic porous tantalum had excellent biocompatibility and could promote new bone formation in vivo. Meanwhile, the osteogenesis of porous tantalum associated with autologous BMSCs was more excellent than only tantalum implantation. Future clinical studies are warranted to verify the clinical efficacy of combined implantation of this domestic porous tantalum associated with autologous BMSCs implantation and compare their efficacy with conventional autologous bone grafting carrying blood vessel in patients needing bone repairing.

  4. Tantalum coating of porous carbon scaffold supplemented with autologous bone marrow stromal stem cells for bone regeneration in vitro and in vivo

    PubMed Central

    Wei, Xiaowei; Wang, Benjie; Wang, Wei; Kang, Kai; Xie, Hui; Liu, Baoyi; Zhang, Xiuzhi; Zhang, Jinsong; Yang, Zhenming

    2016-01-01

    Porous tantalum metal with low elastic modulus is similar to cancellous bone. Reticulated vitreous carbon (RVC) can provide three-dimensional pore structure and serves as the ideal scaffold of tantalum coating. In this study, the biocompatibility of domestic porous tantalum was first successfully tested with bone marrow stromal stem cells (BMSCs) in vitro and for bone tissue repair in vivo. We evaluated cytotoxicity of RVC scaffold and tantalum coating using BMSCs. The morphology, adhesion, and proliferation of BMSCs were observed via laser scanning confocal microscope and scanning electron microscopy. In addition, porous tantalum rods with or without autologous BMSCs were implanted on hind legs in dogs, respectively. The osteogenic potential was observed by hard tissue slice examination. At three weeks and six weeks following implantation, new osteoblasts and new bone were observed at the tantalum–host bone interface and pores. At 12 weeks postporous tantalum with autologous BMSCs implantation, regenerated trabecular equivalent to mature bone was found in the pore of tantalum rods. Our results suggested that domestic porous tantalum had excellent biocompatibility and could promote new bone formation in vivo. Meanwhile, the osteogenesis of porous tantalum associated with autologous BMSCs was more excellent than only tantalum implantation. Future clinical studies are warranted to verify the clinical efficacy of combined implantation of this domestic porous tantalum associated with autologous BMSCs implantation and compare their efficacy with conventional autologous bone grafting carrying blood vessel in patients needing bone repairing. PMID:26843518

  5. Changes in bone regeneration by trehalose coating and basic fibroblast growth factor after implantation of tailor-made bone implants in dogs.

    PubMed

    Choi, Sungjin; Lee, Jongil; Igawa, Kazuyo; Liu, I-Li; Honnami, Muneki; Suzuki, Shigeki; Nishimura, Ryohei; Chung, Ung-Il; Sasaki, Nobuo; Mochizuki, Manabu

    2013-01-01

    In this study, we aimed to determine the effect of trehalose coating and the optimal dose of basic fibroblast growth factor (bFGF), an osteoinductive protein, loaded onto tailor-made bone implants for implant-induced bone formation in vivo. We fabricated tailor-made α-tricalcium phosphate bone implants (11 mm diameter with 2 parallel cylindrical holes). bFGF 0, 1, 10, 100 or 200 μg/implant was incorporated into implants with and without a trehalose coating, and these were subsequently implanted into dogs to correct temporal bone defects of the same size and shape. Four weeks after implantation, we analyzed the bone implants and surrounding tissues by using micro-computed tomography imaging and histological analyses, as well as gross evaluation. No significant difference in new bone formation was observed between implants with and without a trehalose coating at any of the bFGF doses. Bone implants with 100 and 200 μg bFGF showed significantly more new bone formation at the implant site and within the cylindrical holes of the implants than those without bFGF (P<0.05). However, heterotopic bone formation on the skull near the implant was observed in the group that received 200 μg bFGF. These results suggest that 100 μg bFGF is the optimal dose for this implant in dogs, and that the trehalose coating may not be necessary in vivo, probably due to the presence of blood proteins and electrolytes at the implant site.

  6. Photoexcited formation of bone apatite-like coatings on micro-arc oxidized titanium.

    PubMed

    Han, Yong; Xu, Kewei

    2004-12-15

    A novel method to rapidly deposit bone apatite-like coatings on titanium implants in simulated body fluid (SBF) is proposed in this article. The processing was composed of two steps; for example, micro-arc oxidation (MAO) of titanium to form titania films, and UV-light illumination of the titania-coated titanium in SBF. The morphology, crystalline structure, and bond strength of the MAO films were investigated as a function of the applied voltage (in the range of 250-400 V) by using scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectrometry, Fourier transform infrared spectroscopy, adhesion-tensile test, and scratch test. Results showed that the MAO films were porous and nanocrystalline with pore sizes varying from 1 to 3 microm and grain sizes varying from 10-20 to 70-80 nm; the predominant phase in titania films changed from anatase to rutile, and the bond strength of the films decreased from 43.4 to 32.9 MPa as the applied voltage increased from 250 to 400 V. After UV-light illumination of the films in SBF for 2 h, bone apatite-like coating was deposited on the MAO film formed at 250 V. The bond strength of the apatite/titania bilayer was about 44.2 MPa. However, no apatite was observed on the MAO film formed at 400 V after UV-light illumination.

  7. Controllable mineral coatings on scaffolds as carriers for growth factor release for bone tissue engineering

    NASA Astrophysics Data System (ADS)

    Saurez-Gonzalez, Darilis

    The work presented in this document, focused on the development and characterization of mineral coatings on scaffold materials to serve as templates for growth factor binding and release. Mineral coatings were formed using a biomimetic approach that consisted in the incubation of scaffolds in modified simulated body fluids (mSBF). To modulate the properties of the mineral coating, which we hypothesized would dictate growth factor release, we used carbonate (HCO3) concentration in mSBF of 4.2 mM, 25mM, and 100mM. Analysis of the mineral coatings formed using scanning electron microscopy indicated growth of a continuous layer of mineral with different morphologies. X-ray diffraction analysis showed peaks associated with hydroxyapatite. FTIR data confirmed the substitution of HCO3 in the mineral. As the extent of HCO3 substitution increased, the coating exhibited more rapid dissolution kinetics in an environment deficient in calcium and phosphate. The mineral coatings provided an effective mechanism for bioactive growth factor binding and release. Peptide versions of vascular endothelial growth factor (VEGF) and bone morphogenetic protein 2 (BMP2) were bound with efficiencies up to 90% to mineral-coated PCL scaffolds. Recombinant human vascular endothelial growth factor (rhVEGF) also bound to mineral coated scaffolds with lower efficiency (20%) and released with faster release kinetics compared to peptides growth factor. Released rhVEGF induced human umbilical vein endothelial cell (HUVEC) proliferation in vitro and enhanced blood vessel formation in vivo in an intramuscular sheep model. In addition to the use the mineral coatings for single growth factor release, we expanded the concept and bound both an angiogenic (rhVEGF) and osteogenic (mBMP2) growth factor by a simple double dipping process. Sustained release of both growth factors was demonstrated for over 60 days. Released rhVEGF enhanced blood vessel formation in vivo in sheep and its biological activity was

  8. Evaluation in a Dog Model of Three Antimicrobial Glassy Coatings: Prevention of Bone Loss around Implants and Microbial Assessments

    PubMed Central

    López-Píriz, Roberto; Solá-Linares, Eva; Rodriguez-Portugal, Mercedes; Malpica, Beatriz; Díaz-Güemes, Idoia; Enciso, Silvia; Esteban-Tejeda, Leticia; Cabal, Belén; Granizo, Juan José; Moya, José Serafín; Torrecillas, Ramón

    2015-01-01

    Objectives The aim of the present study is to evaluate, in a ligature-induced peri-implantitis model, the efficacy of three antimicrobial glassy coatings in the prevention of biofilm formation, intrasulcular bacterial growth and the resulting peri-implant bone loss. Methods Mandibular premolars were bilaterally extracted from five beagle dogs. Four dental implants were inserted on each hemiarch. Eight weeks after, one control zirconia abutment and three with different bactericidal coatings (G1n-Ag, ZnO35, G3) were connected. After a plaque control period, bacterial accumulation was allowed and biofilm formation on abutments was observed by Scanning Electron Microscopy (SEM). Peri-implantitis was induced by cotton ligatures. Microbial samples and peri-implant crestal bone levels of all implant sites were obtained before, during and after the breakdown period. Results During experimental induce peri-implantitis: colony forming units counts from intrasulcular microbial samples at implants with G1n-Ag coated abutment remained close to the basal inoculum; G3 and ZnO35 coatings showed similar low counts; and anaerobic bacterias counts at control abutments exhibited a logarithmic increase by more than 2. Bone loss during passive breakdown period was no statistically significant. Additional bone loss occurred during ligature-induce breakdown: 0.71 (SD 0.48) at G3 coating, 0.57 (SD 0.36) at ZnO35 coating, 0.74 (SD 0.47) at G1n-Ag coating, and 1.29 (SD 0.45) at control abutments; and statistically significant differences (p<0.001) were found. The lowest bone loss at the end of the experiment was exhibited by implants dressing G3 coated abutments (mean 2.1; SD 0.42). Significance Antimicrobial glassy coatings could be a useful tool to ward off, diminish or delay peri-implantitis progression. PMID:26489088

  9. Amorphous calcium phosphate nanospheres/polylactide composite coated tantalum scaffold: facile preparation, fast biomineralization and subchondral bone defect repair application.

    PubMed

    Zhou, Rong; Xu, Wei; Chen, Feng; Qi, Chao; Lu, Bing-Qiang; Zhang, Hao; Wu, Jin; Qian, Qi-Rong; Zhu, Ying-Jie

    2014-11-01

    Calcium phosphate (CaP) materials are widely used in various biomedical areas such as drug/gene delivery and bone repair/tissue engineering. In this study, amorphous CaP nanospheres synthesized by a simple co-precipitation method are used to prepare the CaP-polylactide (CaP-PLA) composite. Then, the as-prepared CaP-PLA composite is used to coat tantalum (Ta) plates and porous scaffolds. Compared with bare Ta plate, CaP-PLA coated Ta plates show a high performance of surface biomineralization in simulated body fluid (SBF). In addition, the hydrophilicity of the CaP-PLA coated Ta plates is significantly improved. CaP-PLA coated Ta plates with bovine serum albumin (BSA) are prepared and used for the investigation of BSA release in vitro. The experimental results indicate a sustained BSA release property and simultaneous biomineralization of the as-prepared BSA-containing CaP-PLA coated Ta plates. Furthermore, CaP-PLA coated Ta scaffolds are favorable for the human osteoblast-like MG63 cells adhesion and spreading. The vascular endothelial growth factor (VEGF) and transforming growth factor (TGF)-containing CaP-PLA coated porous Ta scaffolds are used for the study of rabbit subchondral bone defect repair, covering with autogeneic periosteums. The as-prepared CaP-PLA composite coated Ta scaffolds are useful to guide the bone regeneration in vivo.

  10. Polyether ether ketone implants achieve increased bone fusion when coated with nano-sized hydroxyapatite: a histomorphometric study in rabbit bone

    PubMed Central

    Johansson, Pär; Jimbo, Ryo; Naito, Yoshihito; Kjellin, Per; Currie, Fredrik; Wennerberg, Ann

    2016-01-01

    Polyether ether ketone (PEEK) possesses excellent mechanical properties similar to those of human bone and is considered the best alternative material other than titanium for orthopedic spine and trauma implants. However, the deficient osteogenic properties and the bioinertness of PEEK limit its fields of application. The aim of this study was to limit these drawbacks by coating the surface of PEEK with nano-scaled hydroxyapatite (HA) minerals. In the study, the biological response to PEEK, with and without HA coating, was investigated. Twenty-four screw-like and apically perforated implants in the rabbit femur were histologically evaluated at 3 weeks and 12 weeks after surgery. Twelve of the 24 implants were HA coated (test), and the remaining 12 served as uncoated PEEK controls. At 3 weeks and 12 weeks, the mean bone–implant contact was higher for test compared to control (P<0.05). The bone area inside the threads was comparable in the two groups, but the perforating hole showed more bone area for the HA-coated implants at both healing points (P<0.01). With these results, we conclude that nano-sized HA coating on PEEK implants significantly improved the osteogenic properties, and in a clinical situation this material composition may serve as an implant where a rapid bone fusion is essential. PMID:27103801

  11. Photoinduced properties of nanocrystalline TiO2-anatase coating on Ti-based bone implants.

    PubMed

    Lorenzetti, Martina; Biglino, Daniele; Novak, Saša; Kobe, Spomenka

    2014-04-01

    The paper reports on the photoinduced properties of hydrothermally treated (HT) titanium used for bone implants. The anatase coatings composed of 30-100nm anatase crystals exhibited high photocatalytic activity and good photo-induced wettability, reaching a superhydrophilic state, despite the larger crystal dimensions than the previously reported optimal ones. These properties are due to a suitable combination of surface texture, roughness, thickness, crystal morphology and particle size, which allowed the two independent photo-induced phenomena to occur simultaneously. The results on caffeine degradation by photocatalysis and the prolonged effect (up to two weeks) of photo-induced wettability in dark suggested a possible applicability of the HT anatase coatings as bacteria-repelling surfaces for body implants, in favor of a better osseointegration in vivo.

  12. Poly(dopamine) coating to biodegradable polymers for bone tissue engineering.

    PubMed

    Tsai, Wei-Bor; Chen, Wen-Tung; Chien, Hsiu-Wen; Kuo, Wei-Hsuan; Wang, Meng-Jiy

    2014-02-01

    In this study, a technique based on poly(dopamine) deposition to promote cell adhesion was investigated for the application in bone tissue engineering. The adhesion and proliferation of rat osteoblasts were evaluated on poly(dopamine)-coated biodegradable polymer films, such as polycaprolactone, poly(l-lactide) and poly(lactic-co-glycolic acid), which are commonly used biodegradable polymers in tissue engineering. Cell adhesion was significantly increased to a plateau by merely 15 s of dopamine incubation, 2.2-4.0-folds of increase compared to the corresponding untreated substrates. Cell proliferation was also greatly enhanced by poly(dopamine) deposition, indicated by shortened cell doubling time. Mineralization was also increased on the poly(dopamine)-deposited surfaces. The potential of poly(dopamine) deposition in bone tissue engineering is demonstrated in this study.

  13. Effect of rhBMP-2 on guided bone regeneration in humans.

    PubMed

    Jung, Ronald E; Glauser, Roland; Schärer, Peter; Hämmerle, Christoph H F; Sailer, Hermann F; Weber, Franz E

    2003-10-01

    The aim of the present clinical study was to test whether or not the addition of recombinant human bone morphogenetic protein-2 (rhBMP-2) to a xenogenic bone substitute mineral (Bio-Oss) will improve guided bone regeneration therapy regarding bone volume, density and maturation. In 11 partially edentulous patients, 34 Brånemark implants were placed at two different sites in the same jaw (five maxillae, six mandibles) requiring lateral ridge augmentation. The bone defects were randomly assigned to test and control treatments: the test and the control defects were both augmented with the xenogenic bone substitute and a resorbable collagen membrane (Bio-Gide). At the test sites, the xenogenic bone substitute mineral was coated with rhBMP-2 in a lyophilization process. Following implant insertion (baseline), the peri-implant bone defect height was measured from the implant shoulder to the first implant-bone contact. After an average healing period of 6 months (SD 0.17, range 5.7-6.2), the residual defects were again measured and trephine burs were used to take 22 bone biopsies from the augmented regions. The healing period was uneventful except for one implant site that showed a wound dehiscence, which spontaneously closed after 4 weeks. Later at reentry, all implants were stable. At baseline, the mean defect height was 7.0 mm (SD 2.67, range 3-12 mm) at test and 5.8 mm (SD 1.81, range 3-8 mm) at control sites. At reentry, the mean defect height decreased to 0.2 mm (SD 0.35, range 0-1 mm) at test sites (corresponding to 96% vertical defect fill) and to 0.4 mm (SD 0.66, range 0-2 mm) at the control site (vertical defect fill of 91%). Reduction in defect height from baseline to reentry for both test and control sites was statistically significant (Wilcoxon P<0.01). Histomorphometric analysis showed an average area density of 37% (SD 11.2, range 23-51%) newly formed bone at test sites and 30% (SD 8.9, range 18-43%) at control sites. The fraction of mineralized bone

  14. Bone quality around bioactive silica-based coated stainless steel implants: analysis by micro-Raman, XRF and XAS techniques.

    PubMed

    Ballarre, Josefina; Desimone, Paula M; Chorro, Matthieu; Baca, Matías; Orellano, Juan Carlos; Ceré, Silvia M

    2013-11-01

    Surface modification of surgical stainless steel implants by sol gel coatings has been proposed as a tool to generate a surface that besides being protective could also create a "bioactive" interface to generate a natural bonding between the metal surface and the existing bone. The aim of this work is to analyze the quality and bone formation around hybrid bioactive coatings containing glass-ceramic particles, made by sol-gel process on 316L stainless steel used as permanent implant in terms of mineralization, calcium content and bone maturity with micro Raman, X-ray microfluorescence and X-ray absorption techniques. Uncoated implants seem to generate a thin bone layer at the beginning of osseointegration process and then this layer being separated from the surface with time. The hybrid coatings without glass-ceramic particles generate new bone around implants, with high concentration of Ca and P at the implant/tissue interface. This fact seems to be related with the presence of silica nanoparticles in the layer. The addition of bioactive particles promotes and enhances the bone quality with a homogeneous Ca and P content and a low rate of beta carbonate substitution and crystallinity, similar to young and mechanical resistant bone.

  15. Introduction of a coiled solid-phase microextraction fiber based on a coating of animal bone waste for chromatographic analysis.

    PubMed

    Razmi, Habib; Farrokhzadeh, Samaneh

    2017-03-07

    We attempt to introduce animal bone waste as a coating material with an organic-inorganic structure for the fabrication of a coiled solid-phase microextraction fiber for the first time. The coiled fiber was simply prepared with the use of copper wire and coated with bone waste suspension through the dip-coating method. The bone waste coating was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction analysis. It was applied as new type of solid-phase microextraction fiber for preconcentration of polycyclic aromatic hydrocarbons before determination by high-performance liquid chromatography with UV detection. A wide linear range 0.01-99.0 μg/L and limits of detection in the range 3.0-11.1 ng/L were obtained at optimized conditions. The bone waste coated coiled solid-phase microextraction fiber has promise in sample preparation techniques because it is cost effective, available, stable in aqueous and organic solutions, environmentally friendly, and easy to fabricate and operate.

  16. The fluoride coated AZ31B magnesium alloy improves corrosion resistance and stimulates bone formation in rabbit model.

    PubMed

    Sun, Wei; Zhang, Guangdao; Tan, Lili; Yang, Ke; Ai, Hongjun

    2016-06-01

    This study aimed to evaluate the effect of fluorine coated Mg alloy and clarify its mechanism in bone formation. We implanted the fluorine coated AZ31B Mg alloy screw (group F) in rabbit mandibular and femur in vivo. Untreated AZ31B Mg alloy screw (group A) and titanium screw (group T) were used as control. Then, scanning electron microscopy, the spectral energy distribution analysis, hard and decalcified bone tissues staining were performed. Immunohistochemistry was employed to examine the protein expressions of bone morphogenetic protein 2 (BMP-2) and collagen type I in the vicinity of the implant. Compared with the group A, the degradation of the alloy was reduced, the rates of Mg corrosion and Mg ion release were slowed down, and the depositions of calcium and phosphate increased in the group F in the early stage of implantation. Histological results showed that fluorine coated Mg alloy had well osteogenic activity and biocompatibility. Moreover, fluoride coating obviously up-regulated the expressions of collagen type I and BMP-2. This study confirmed that the fluorine coating might improve the corrosion resistance of AZ31B Mg alloy and promote bone formation by up-regulated the expressions of collagen type I and BMP-2.

  17. Platelet lysate coating on scaffolds directly and indirectly enhances cell migration, improving bone and blood vessel formation.

    PubMed

    Leotot, Julie; Coquelin, Laura; Bodivit, Gwellaouen; Bierling, Philippe; Hernigou, Philippe; Rouard, Helene; Chevallier, Nathalie

    2013-05-01

    Suitable colonization and vascularization of tissue-engineered constructs after transplantation represent critical steps for the success of bone repair. Human platelet lysate (hPL) is composed of numerous growth factors known for their proliferative, differentiative and chemo-attractant effects on various cells involved in wound healing and bone growth. The aim of this study was to determine whether the delivery of human mesenchymal stromal cells (hMSC) seeded on hPL-coated hydroxyapatite/β-tricalcium phosphate (HA/β-TCP) scaffolds could enhance vascularization and bone formation, as well as to investigate the mechanisms by which hMSC participate in tissue regeneration. Our study demonstrates that hPL can be coated on HA/β-TCP scaffolds, which play direct and indirect effects on implanted and/or resident stem cells. Effectively, we show that hPL coating directly increases chemo-attraction to and adhesion of hMSC and endothelial cells on the scaffold. Moreover, we show that hPL coating induces hMSC to produce and secrete pro-angiogenic proteins (placental growth factor and vascular endothelial growth factor) which allow the proliferation and specific chemo-attraction of endothelial cells in vitro, thus improving in vivo neovascularization and new bone formation. This study highlights the potential of functionalizing biomaterials with hPL and shows that this growth factor combination can have synergistic effects leading to enhanced bone and blood vessel formation.

  18. Improvement of the compressive strength of a cuttlefish bone-derived porous hydroxyapatite scaffold via polycaprolactone coating.

    PubMed

    Kim, Beom-Su; Kang, Hyo Jin; Lee, Jun

    2013-10-01

    Cuttlefish bones (CBs) have emerged as attractive biomaterials because of their porous structure and components that can be converted into hydroxyapatite (HAp) via a hydrothermal reaction. However, their brittleness and low strength restrict their application in bone tissue engineering. Therefore, to improve the compressive strength of the scaffold following hydrothermal conversion to a HAp form of CB (CB-HAp), the scaffold was coated using a polycaprolactone (PCL) polymer at various concentrations. In this study, raw CB was successfully converted into HAp via a hydrothermal reaction. We then evaluated their surface properties and composition by scanning electron microscopy and X-ray diffraction analysis. The CB-HAp coated with PCL showed improved compressive performance and retained a microporous structure. The compressive strength was significantly increased upon coating with 5 and 10% PCL, by 2.09- and 3.30-fold, respectively, as compared with uncoated CB-HAp. However, coating with 10% PCL resulted in a reduction in porosity. Furthermore, an in vitro biological evaluation demonstrated that MG-63 cells adhered well, proliferated and were able to be differentiated on the PCL-coated CB-HAp scaffold, which was noncytotoxic. These results suggest that a simple coating method is useful to improve the compressive strength of CB-HAp for bone tissue engineering applications.

  19. Evaluation of bone loss in antibacterial coated dental implants: An experimental study in dogs.

    PubMed

    Godoy-Gallardo, Maria; Manzanares-Céspedes, Maria Cristina; Sevilla, Pablo; Nart, José; Manzanares, Norberto; Manero, José M; Gil, Francisco Javier; Boyd, Steven K; Rodríguez, Daniel

    2016-12-01

    The aim of this study was to evaluate the in vivo effect of antibacterial modified dental implants in the first stages of peri-implantitis. Thirty dental implants were inserted in the mandibular premolar sites of 5 beagle dogs. Sites were randomly assigned to Ti (untreated implants, 10units), Ti_Ag (silver electrodeposition treatment, 10units), and Ti_TSP (silanization treatment, 10units). Coated implants were characterized by scanning electron microscopy, interferometry and X-ray photoelectron spectroscopy. Two months after implant insertion, experimental peri-implantitis was initiated by ligature placement. Ligatures were removed 2months later, and plaque formation was allowed for 2 additional months. Clinical and radiographic analyses were performed during the study. Implant-tissue samples were prepared for micro computed tomography, backscattered scanning electron microscopy, histomorphometric and histological analyses and ion release measurements. X-ray, SEM and histology images showed that vertical bone resorption in treated implants was lower than in the control group (P<0.05). This effect is likely due to the capacity of the treatments to reduce bacteria colonization on the implant surface. Histological analysis suggested an increase of peri-implant bone formation on silanized implants. However, the short post-ligature period was not enough to detect differences in clinical parameters among implant groups. Within the limits of this study, antibacterial surface treatments have a positive effect against bone resorption induced by peri-implantitis.

  20. Antibacterial activity and increased bone marrow stem cell functions of Zn-incorporated TiO2 coatings on titanium.

    PubMed

    Hu, H; Zhang, W; Qiao, Y; Jiang, X; Liu, X; Ding, C

    2012-02-01

    In this work, zinc was incorporated into TiO2 coatings on titanium by plasma electrolytic oxidation to obtain the implant with good bacterial inhibition ability and bone-formability. The porous and nanostructured Zn-incorporated TiO2 coatings are built up from pores smaller than 5 μm and grains 20-100 nm in size, in which the element Zn exists as ZnO. The results obtained from the antibacterial studies suggest that the Zn-incorporated TiO2 coatings can greatly inhibit the growth of both Staphylococcus aureus and Escherichia coli, and the ability to inhibit bacteria can be improved by increasing the Zn content in the coatings. Moreover, the in vitro cytocompatibility evaluation demonstrates that the adhesion, proliferation and differentiation of rat bone marrow stem cells (bMSC) on Zn-incorporated coatings are significantly enhanced compared with Zn-free coating and commercially pure Ti plate, and no cytotoxicity appeared on any of the Zn-incorporated TiO2 coatings. Moreover, bMSC express higher level of alkaline phosphatase activity on Zn-incorporated TiO2 coatings and are induced to differentiate into osteoblast cells. The better antibacterial activity, cytocompatibility and the capability to promote bMSC osteogenic differentiation of Zn-incorporated TiO2 coatings may be attributed to the fact that Zn ions can be slowly and constantly released from the coatings. In conclusion, innovative Zn-incorporated TiO2 coatings on titanium with excellent antibacterial activity and biocompatibility are promising candidates for orthopedic and dental implants.

  1. In Vitro Corrosion and Cytocompatibility Properties of Nano-Whisker Hydroxyapatite Coating on Magnesium Alloy for Bone Tissue Engineering Applications

    PubMed Central

    Yang, Huawei; Yan, Xueyu; Ling, Min; Xiong, Zuquan; Ou, Caiwen; Lu, Wei

    2015-01-01

    We report here the successful fabrication of nano-whisker hydroxyapatite (nHA) coatings on Mg alloy by using a simple one-step hydrothermal process in aqueous solution. The nHA coating shows uniform structure and high crystallinity. Results indicate that nHA coating is promising for improving the in vitro corrosion and cytocompatibility properties of Mg-based implants and devices for bone tissue engineering. In addition, the simple hydrothermal deposition method used in the current study is also applicable to substrates with complex shapes or surface geometries. PMID:25789500

  2. Composite coating of 58S bioglass and hydroxyapatite on a poly (ethylene terepthalate) artificial ligament graft for the graft osseointegration in a bone tunnel

    NASA Astrophysics Data System (ADS)

    Li, Hong; Wu, Yang; Ge, Yunsheng; Jiang, Jia; Gao, Kai; Zhang, Pengyun; Wu, Lingxiang; Chen, Shiyi

    2011-09-01

    The purpose of this study was to determine the effect of the combination of hydroxyapatite (HA) and bioglass (BG) on polyethylene terephthalate (PET) artificial ligament graft osseointegration within the bone tunnel. The results of in vitro culturing of MC3T3-E1 mouse osteoblastic cells proved that this HA/BG composite coating can promote the cell compatibility of grafts. A rabbit extraarticular tendon-to-bone healing model was used to evaluate the effect of this composite coating on PET artificial ligaments in vivo. The final results demonstrated that HA/BG coating improved new bone formation at the graft-bone interface and increased the load-to-failure property of graft in bone tunnel compared to the control group at early time. The study has shown that HA/BG composite coating on the PET artificial ligament surface has a positive effect in the induction of artificial ligament osseointegration within the bone tunnel.

  3. Host tissue reactions of non-demineralized autogenic and xenogenic dentin blocks implanted in a non-osteogenic environment. An experimental study in rabbits.

    PubMed

    Al-Asfour, Adel; Farzad, Payam; Andersson, Lars; Joseph, Bobby; Dahlin, Christer

    2014-06-01

    Dentoalveolar ankylosis with osseous replacement is often seen after replantation of avulsed teeth, and this process may be used for preservation of alveolar crests after trauma. Its exact mechanisms with regard to osteoinductive properties are not yet fully understood and need to be systematically investigated. Dentin can possibly act as a slow-releasing carrier of bone morphogenic proteins (BMP), and this property of dentin has been proposed to be used as an alternative or supplement to bone grafting in the maxillofacial region. We aimed to initially asses host tissue reactions to dentin by implanting dentin blocks of autogenic and xenogenic human origin in rabbit connective tissue of the abdominal wall and femoral muscle. Animals were sacrificed after a period of 3 months, and histological processing, sectioning and examinations were carried out. Bone formation, cell counts and thickness of capsule surrounding the grafts were evaluated. Only minor signs of heterotopic bone formation were seen. There were no significant differences between autografts and xenografts or grafts implanted in connective tissue or muscle with regards to tissue reactions except for a significant difference (P = 0.018) in findings of more local inflammatory cells in relation to grafts placed in connective tissue in the autograft group. We conclude that during the time frame of this study, non-demineralized dentin, whether autogenous or xenogenic did not have the potential to induce bone formation when implanted in non-osteogenic areas such as the abdominal wall and abdominal muscle of rabbits.

  4. Development of bioactive glass based scaffolds for controlled antibiotic release in bone tissue engineering via biodegradable polymer layered coating.

    PubMed

    Nooeaid, Patcharakamon; Li, Wei; Roether, Judith A; Mouriño, Viviana; Goudouri, Ourania-Menti; Schubert, Dirk W; Boccaccini, Aldo R

    2014-12-01

    Highly porous 45S5 Bioglass(®)-based scaffolds coated with two polymer layers were fabricated to serve as a multifunctional device with controlled drug release capability for bone regeneration applications. An interior poly(d,l-lactide)/poly(ethylene glycol)-(polypropylene glycol)-poly(ethylene glycol) triblock copolymer (Pluronic P123) coating improved the mechanical stability of Bioglass-based scaffolds, while an exterior natural polymer (alginate or gelatin) coating served as an antibiotic drug carrier. The results showed improved mechanical properties of Bioglass-based scaffolds by the bilayer polymer coating. In addition, hydrochloride tetracycline loaded in either alginate or gelatin coatings was released rapidly at the initial stage (∼1 h), while the released rate subsequently decreased and was sustained for 14 days in phosphate buffered saline. Therefore, these layered polymer coated scaffolds exhibit attractive characteristics in terms of improved mechanical properties and controlled drug release, simultaneously with the added advantage that the drug release rate is decoupled from the intrinsic scaffold Bioglass degradation mechanism. The layered polymer coated scaffolds are of interest for drug-delivery enhanced bone regeneration applications.

  5. Peri-implant bone response around a human hydroxyapatite-coated implant retrieved after a 10-year loading period: a case report.

    PubMed

    Iezzi, Giovanna; Malchiodi, Luciano; Quaranta, Alessandro; Ghensi, Paolo; Piattelli, Adriano

    2013-01-01

    This case report presents a histologic and histomorphometric evaluation of the peri-implant tissues of a HA-coated implant retrieved due to peri-implantitis after a 10-year loading period. The implant was retrieved with a trephine and treated to obtain thin ground sections. At low-power magnification mostly compact, mature bone with small marrow spaces could be observed at the interface with the implant. The coating was always present in the areas where bone was detected, the bone was always in close contact with the coating, and there was no detachment between the metal and coating or between the coating and bone. Areas of bone remodeling were demonstrated by the presence of many secondary osteons and reversal lines close to the implant surface. The bone-implant contact percentage was 36.3% ± 1.2%. The percentage of the implant surface covered by the HA coating without bone, where bone may have detached during retrieval, was 32.6% ± 2.8%. This HA-coated implant, continued to demonstrate more than adequate BIC after many years of function and the potential to maintain osseointegration in the long term.

  6. Radiologic Evaluation of Bone Loss at Implants with Biocide Coated Titanium Abutments: A Study in the Dog

    PubMed Central

    López-Píriz, Roberto; Solá-Linares, Eva; Granizo, Juan J.; Díaz-Güemes, Idohia; Enciso, Silvia; Bartolomé, José F.; Cabal, Belén; Esteban-Tejeda, Leticia; Torrecillas, Ramón; Moya, José S.

    2012-01-01

    The objective of the present study is to evaluate bone loss at implant abutments coated with a soda-lime glass containing silver nanoparticles subjected to experimental peri-implantitis. Five beagle dogs were used in the experiments, 3 implants were installed in each quadrant of the mandibles. Glass/n-Ag coted abutments were connected to implant platform. Cotton floss ligatures were placed in a submarginal position around the abutment necks and the animals were subject to a diet which allowed plaque accumulation, and after 15 weeks the dogs were sacrificed. Radiographs of all implant sites were obtained at the beginning and at the end of the experimentally induced peri-implantitis. The radiographic examination indicated that significant amounts of additional bone loss occurred in implants without biocide coating, considering both absolute and relative values of bone loss. Percentages of additional bone loss observed in implants dressed with a biocide coated abutment were about 3 times lower (p<0.006 distal aspect; and p<0.031 at mesial aspect) than the control ones. Within the limits of the present study it seems promising the use of soda-lime glass/nAg coatings on abutments to prevent peri-implant diseases. PMID:23285206

  7. Photo-acoustic excitation and detection of guided ultrasonic waves in bone samples covered by a soft coating layer

    NASA Astrophysics Data System (ADS)

    Zhao, Zuomin; Moilanen, Petro; Karppinen, Pasi; Määttä, Mikko; Karppinen, Timo; Hæggström, Edward; Timonen, Jussi; Myllylä, Risto

    2012-12-01

    Photo-acoustic (PA) excitation was combined with skeletal quantitative ultrasound (QUS) for multi-mode ultrasonic assessment of human long bones. This approach permits tailoring of the ultrasonic excitation and detection so as to efficiently detect the fundamental flexural guided wave (FFGW) through a coating of soft tissue. FFGW is a clinically relevant indicator of cortical thickness. An OPO laser with tunable optical wavelength, was used to excite a photo-acoustic source in the shaft of a porcine femur. Ultrasonic signals were detected by a piezoelectric transducer, scanning along the long axis of the bone, 20-50 mm away from the source. Five femurs were measured without and with a soft coating. The coating was made of an aqueous gelatin-intralipid suspension that optically and acoustically mimicked real soft tissue. An even coating thickness was ensured by using a specific mold. The optical wave length of the source (1250 nm) was tuned to maximize the amplitude of FFGW excitation at 50 kHz frequency. The experimentally determined FFGW phase velocity in the uncoated samples was consistent with that of the fundamental antisymmetric Lamb mode (A0). Using appropriate signal processing, FFGW was also identified in the coated bone samples, this time with a phase velocity consistent with that theoretically predicted for the first mode of a fluid-solid bilayer waveguide (BL1). Our results suggest that photo-acoustic quantitative ultrasound enables assessment of the thickness-sensitive FFGW in bone through a layer of soft tissue. Photo-acoustic characterization of the cortical bone thickness may thus become possible.

  8. Mesoporous silica coatings for cephalosporin active release at the bone-implant interface

    NASA Astrophysics Data System (ADS)

    Rădulescu, Dragoş; Voicu, Georgeta; Oprea, Alexandra Elena; Andronescu, Ecaterina; Grumezescu, Valentina; Holban, Alina Maria; Vasile, Bogdan Stefan; Surdu, Adrian Vasile; Grumezescu, Alexandru Mihai; Socol, Gabriel; Mogoantă, Laurenţiu; Mogoşanu, George Dan; Balaure, Paul Cătălin; Rădulescu, Radu; Chifiriuc, Mariana Carmen

    2016-06-01

    In this study, we investigated the potential of MAPLE-deposited coatings mesoporous silica nanoparticles (MSNs) to release Zinforo (ceftarolinum fosmil) in biologically active form. The MSNs were prepared by using a classic procedure with cetyltrimethylammonium bromide as sacrificial template and tetraethylorthosilicate as the monomer. The Brunauer-Emmett-Teller (BET) and transmission electron microscopy (TEM) analyses revealed network-forming granules with diameters under 100 nm and an average pore diameter of 2.33 nm. The deposited films were characterized by SEM, TEM, XRD and IR. Microbiological analyses performed on ceftaroline-loaded films demonstrated that the antibiotic was released in an active form, decreasing the microbial adherence rate and colonization of the surface. Moreover, the in vitro and in vivo assays proved the excellent biodistribution and biocompatibility of the prepared systems. Our results suggest that the obtained bioactive coatings possess a significant potential for the design of drug delivery systems and antibacterial medical-use surfaces, with great applications in bone implantology.

  9. PCL-coated hydroxyapatite scaffold derived from cuttlefish bone: in vitro cell culture studies.

    PubMed

    Milovac, Dajana; Gamboa-Martínez, Tatiana C; Ivankovic, Marica; Gallego Ferrer, Gloria; Ivankovic, Hrvoje

    2014-09-01

    In the present study, we examined the potential of using highly porous poly(ε-caprolactone) (PCL)-coated hydroxyapatite (HAp) scaffold derived from cuttlefish bone for bone tissue engineering applications. The cell culture studies were performed in vitro with preosteoblastic MC3T3-E1 cells in static culture conditions. Comparisons were made with uncoated HAp scaffold. The attachment and spreading of preosteoblasts on scaffolds were observed by Live/Dead staining Kit. The cells grown on the HAp/PCL composite scaffold exhibited greater spreading than cells grown on the HAp scaffold. DNA quantification and scanning electron microscopy (SEM) confirmed a good proliferation of cells on the scaffolds. DNA content on the HAp/PCL scaffold was significantly higher compared to porous HAp scaffolds. The amount of collagen synthesis was determined using a hydroxyproline assay. The osteoblastic differentiation of the cells was evaluated by determining alkaline phosphatase (ALP) activity and collagen type I secretion. Furthermore, cell spreading and cell proliferation within scaffolds were observed using a fluorescence microscope.

  10. Bone char surface modification by nano-gold coating for elemental mercury vapor removal

    NASA Astrophysics Data System (ADS)

    Assari, Mohamad javad; Rezaee, Abbas; Rangkooy, Hossinali

    2015-07-01

    The present work was done to develop a novel nanocomposite using bone char coated with nano-gold for capture of elemental mercury (Hg0) from air. The morphologies, structures, and chemical constitute of the prepared nanocomposite were evaluated by UV-VIS-NIR, dynamic light-scattering (DLS), X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infra-red (FTIR) spectroscopy, and energy dispersive X-ray spectroscopy (EDS). The capture performance of nanocomposite was evaluated in a needle trap for mercury vapor. An on-line setup based on cold vapor atomic absorption spectrometry (CVAAS) was designed for Hg0 determination. Dynamic capacity of nanocomposite for Hg0 was shown high efficient operating capacity of 586.7 μg/g. As temperature increases, the dynamic adsorption capacity of the nanocomposite was decreased, which are characteristics of physicosorption processes. It was found that the surface modification of bone char with nano-gold has various advantages such as high operating dynamic adsorption capacity and low cost preparation. It was also demonstrated that the developed nanocomposite is suitable for on-line monitoring of Hg0. It could be applied for the laboratory and field studies.

  11. Technical note: Bone DNA extraction and purification using silica-coated paramagnetic beads.

    PubMed

    Dukes, Mary J; Williams, Audra L; Massey, Corina M; Wojtkiewicz, Patrick W

    2012-07-01

    The goal of this study was to develop a simple method to improve DNA recovery from challenging bone samples. To this end, an optimized procedure was developed that combined the demineralization and DNA extraction into a single step, followed by DNA purification using an automated silica-coated paramagnetic bead procedure. This method replaced a previous silica-membrane-based procedure, which was able to recover sufficient DNA to obtain full autosomal and Y chromosome STR profiles from greater than 90% of the samples, including samples greater than 20 years old. The development process began with the evaluation of buffer and demineralization systems to determine the best reagent combination. During the developmental process, we observed that the addition of EDTA and DTT affected silica-based DNA purification methods by raising the pH of the digest buffer. The protocols with buffer ATL, PK, EDTA, and DTT followed by lowering the pH with sodium acetate just before purification resulted in the best yields. The method reduced the extraction volume from 10 to 1.5 ml and used commercially available reagents already being utilized in forensic DNA casework. Because of the simplicity and small volume needed for the procedure, many steps where contamination could be introduced have been eliminated or minimized. This study demonstrated a new method of recovering DNA from bone samples capable of extracting trace quantities of DNA, removing potential inhibitors, and minimizing the potential for exogenous DNA contamination.

  12. A systematic review and meta-analysis on the influence of biological implant surface coatings on periimplant bone formation.

    PubMed

    Jenny, Gregor; Jauernik, Johanna; Bierbaum, Susanne; Bigler, Martin; Grätz, Klaus W; Rücker, Martin; Stadlinger, Bernd

    2016-11-01

    This systematic review and meta-analysis evaluated the influence of biological implant surface coatings on periimplant bone formation in comparison to an uncoated titanium reference surface in experimental large animal models. The analysis was structured according to the PRISMA criteriae. Of the1077 studies, 30 studies met the inclusion criteriae. Nineteen studies examined the bone implant contact (BIC) and were included in the meta-analysis. Overall, the mean increase in BIC for the test surfaces compared to the reference surfaces was 3.7 percentage points (pp) (95% CI -3.9-11.2, p = 0.339). Analyzing the increase in BIC for specific coated surfaces in comparison to uncoated reference surfaces, inorganic surface coatings showed a significant mean increase in BIC of 14.7 pp (95% CI 10.6-18.9, p < 0.01), extracellular matrix (ECM) surface coatings showed an increase of 10.0 pp (95% CI 4.4-15.6, p < 0.001), and peptide coatings showed a statistical trend with 7.1 pp BIC increase (95% CI -0.8-15.0, p = 0.08). In this review, no statistically significant difference could be found for growth factor surface coatings (observed difference -3.3 pp, 95% CI -16.5-9.9, p = 0.6). All analyses are exploratory in nature. The results show a statistically significant effect of inorganic and ECM coatings on periimplant bone formation. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2898-2910, 2016.

  13. Designer Dual Therapy Nanolayered Implant Coatings Eradicate Biofilms and Accelerate Bone Tissue Repair.

    PubMed

    Min, Jouha; Choi, Ki Young; Dreaden, Erik C; Padera, Robert F; Braatz, Richard D; Spector, Myron; Hammond, Paula T

    2016-04-26

    Infections associated with orthopedic implants cause increased morbidity and significant healthcare cost. A prolonged and expensive two-stage procedure requiring two surgical steps and a 6-8 week period of joint immobilization exists as today's gold standard for the revision arthroplasty of an infected prosthesis. Because infection is much more common in implant replacement surgeries, these issues greatly impact long-term patient care for a continually growing part of the population. Here, we demonstrate that a single-stage revision using prostheses coated with self-assembled, hydrolytically degradable multilayers that sequentially deliver the antibiotic (gentamicin) and the osteoinductive growth factor (BMP-2) in a time-staggered manner enables both eradication of established biofilms and complete and rapid bone tissue repair around the implant in rats with induced osteomyelitis. The nanolayered construct allows precise independent control of release kinetics and loading for each therapeutic agent in an infected implant environment. Antibiotics contained in top layers can be tuned to provide a rapid release at early times sufficient to eliminate infection, followed by sustained release for several weeks, and the underlying BMP-2 component enables a long-term sustained release of BMP-2, which induced more significant and mechanically competent bone formation than a short-term burst release. The successful growth factor-mediated osteointegration of the multilayered implants with the host tissue improved bone-implant interfacial strength 15-fold when compared with the uncoated one. These findings demonstrate the potential of this layered release strategy to introduce a durable next-generation implant solution, ultimately an important step forward to future large animal models toward the clinic.

  14. Comparison of new bone formation, implant integration, and biocompatibility between RGD-hydroxyapatite and pure hydroxyapatite coating for cementless joint prostheses--an experimental study in rabbits.

    PubMed

    Bitschnau, Achim; Alt, Volker; Böhner, Felicitas; Heerich, Katharina Elisabeth; Margesin, Erika; Hartmann, Sonja; Sewing, Andreas; Meyer, Christof; Wenisch, Sabine; Schnettler, Reinhard

    2009-01-01

    This is the first work to report on additional Arginin-Glycin-Aspartat (RGD) coating on precoated hydroxyapatite (HA) surfaces regarding new bone formation, implant bone contact, and biocompatibility compared to pure HA coating and uncoated stainless K-wires. There were 39 rabbits in total with 6 animals for the RGD-HA and HA group for the 4 week time period and 9 animals for each of the 3 implant groups for the 12 week observation. A 2.0 K-wire either with RGD-HA or with pure HA coating or uncoated was placed into the intramedullary canal of the tibia. After 4 and 12 weeks, the tibiae were harvested and three different areas of the tibia were assessed for quantitative and qualitative histology for new bone formation, direct implant bone contact, and formation of multinucleated giant cells. Both RGD-HA and pure HA coating showed statistically higher new bone formation and implant bone contact after 12 weeks than the uncoated K-wire. There were no significant differences between the RGD-HA and the pure HA coating in new bone formation and direct implant bone contact after 4 and 12 weeks. The number of multinucleated giant did not differ significantly between the RGD-HA and HA group after both time points. Overall, no significant effects of an additional RGD coating on HA surfaces were detected in this model after 12 weeks.

  15. Bone defect rehabilitation using lyophilized bone preshaped on a stereolithographic model

    PubMed Central

    Bohner, Lauren Oliveira Lima; Mukai, Eduardo; Mukai, Sueli; Tortamano, Pedro; Sesma, Newton

    2016-01-01

    Bone grafting provides ideal conditions to the patient's rehabilitation with dental implants. In addition, prototyped tridimensional models allow the surgical procedure to be simulated and enable important anatomic structures to be visualized. To present a bone defect rehabilitated with xenogenic bone preshaped on a stereolithographic model and the follow-up after 7 years of treatment. The present case report describes a bone defect rehabilitated with a lyophilized bone block preshaped on a stereolithographic model. The patient, a 56-year-old woman, was referred to the dental office presenting a bone defect in the anterior maxilla. Bone regeneration intervention was performed with xenogenic grafting and barrier membrane. The follow-up of the postoperative period and after 7 years is presented. After 7 years, the tomographic exam showed the maintenance of bone at the grafted site, representing the long-term success of the treatment. PMID:27630509

  16. Metal-ion release from titanium and TiN coated implants in rat bone*

    NASA Astrophysics Data System (ADS)

    Ferrari, F.; Miotello, A.; Pavloski, L.; Galvanetto, E.; Moschini, G.; Galassini, S.; Passi, P.; Bogdanović, S.; Fazinić, S.; Jaksić, M.; Valković, V.

    1993-06-01

    Titanium is a good material for dental and orthopaedic implants, but many authors reported that it releases ions into the surrounding tissues and into the serum. Titanium nitride has good mechanical properties and chemical inertless and may be employed as an implant coating material. In this experiment, pure titanium and SiO 2 coated with TiN implants were inserted in the tibia of rats. After thirty days, the bones were taken and examined by a proton microprobe. TiN-coated implants showed a lower ion release into the bone compared with pure titanium. This suggests that TiN may be a good coating for endosseous implants.

  17. Plasma-sprayed hydroxyapatite coating on carbon/carbon composite scaffolds for bone tissue engineering and related tests in vivo.

    PubMed

    Cao, Ning; Dong, Jianwen; Wang, Qiangxiu; Ma, Quansheng; Wang, Feng; Chen, Huaying; Xue, Chengqian; Li, Musen

    2010-03-01

    The bioactive hydroxyapatite (HA) coatings were successfully prepared on carbon/carbon composites (C/C) by means of sand-blasting pretreatment and plasma-spraying technology. X-ray diffraction was employed to analyze the phase constitute of the coatings. Meanwhile, the bond strength between the HA coatings and C/C substrates was determined via shear test. Experimental results show that the coatings constitute HA, CaO, and other amorphous phosphates. The post heat treatment could effectively increase crystallization and purity of the coatings. Through observation and analysis by electron microprobe and scanning electron microscopy, it is concluded that the bond strength of the plasma-sprayed HA coatings on C/C is mainly determined by the interface structure and can be further improved by the post heat treatment. Meanwhile, the implantation in vivo was carried out in hybrid goats. The histological observation revealed that the osteoplaque gradually grew on the surface of the HA coatings and the pure C/C surface was covered by the fibrous tissues. No inflammation symptoms were found in the bone tissue around the implants.

  18. Bone ingrowth potential of electron beam and selective laser melting produced trabecular-like implant surfaces with and without a biomimetic coating.

    PubMed

    Biemond, J E; Hannink, G; Verdonschot, N; Buma, P

    2013-03-01

    The bone ingrowth potential of trabecular-like implant surfaces produced by either selective laser melting (SLM) or electron beam melting (EBM), with or without a biomimetic calciumphosphate coating, was examined in goats. For histological analysis and histomorphometry of bone ingrowth depth and bone implant contact specimens were implanted in the femoral condyle of goats. For mechanical push out tests to analyse mechanical implant fixation specimens were implanted in the iliac crest. The follow up periods were 4 (7 goats) and 15 weeks (7 goats). Both the SLM and EBM produced trabecular-like structures showed a variable bone ingrowth after 4 weeks. After 15 weeks good bone ingrowth was found in both implant types. Irrespective to the follow up period, and the presence of a coating, no histological differences in tissue reaction around SLM and EBM produced specimens was found. Histological no coating was detected at 4 and 15 weeks follow up. At both follow up periods the mechanical push out strength at the bone implant interface was significantly lower for the coated SLM specimens compared to the uncoated SLM specimens. The expected better ingrowth characteristics and mechanical fixation strength induced by the coating were not found. The lower mechanical strength of the coated specimens produced by SLM is a remarkable result, which might be influenced by the gross morphology of the specimens or the coating characteristics, indicating that further research is necessary.

  19. Peri-implant and systemic effects of high-/low-affinity bisphosphonate-hydroxyapatite composite coatings in a rabbit model with peri-implant high bone turnover

    PubMed Central

    2012-01-01

    Background Hydroxyapatite (HA) coatings composed with bisphosphonates (BPs) which have high mineral-binding affinities have been confirmed to successfully enhance implant stability. However, few previous studies focused on HA coatings composed with low-affinity BPs or on systemic effects of locally released BPs. Methods In this long-term study, we developed two kinds of BP-HA composite coatings using either high-affinity BP (alendronate, ALN) or low-affinity BP (risedronate, RIS). Thirty-six rabbits were divided into three groups according to different coating applications (group I: HA, group II: ALN-HA, and group III: RIS-HA). Implants were inserted into the proximal region of the medullary cavity of the left tibiay. At insertion, 2 × 108 wear particles were injected around implants to induce a peri-implant high bone turnover environment. Both local (left tibias) and systemic (right tibias and lumbar vertebrae) inhibitory effect on bone resorption were compared, including bone-implant integration, bone architecture, bone mineral density (BMD), implant stability, and serum levels of bone turnover markers. Results The results indicated that ALN-HA composite coating, which could induce higher bone-implant contact (BIC) ratio, bone mass augmentation, BMD, and implant stability in the peri-implant region, was more potent on peri-implant bone, while RIS-HA composite coating, which had significant systemic effect, was more potent on non-peri-implant bone, especially lumbar vertebrae. Conclusions It is instructive and meaningful to further clinical studies that we could choose different BP-HA composite coatings according to the patient’s condition. PMID:22686414

  20. Bone Loss at Implant with Titanium Abutments Coated by Soda Lime Glass Containing Silver Nanoparticles: A Histological Study in the Dog

    PubMed Central

    Martinez, Arturo; Guitián, Francisco; López-Píriz, Roberto; Bartolomé, José F.; Cabal, Belén; Esteban-Tejeda, Leticia; Torrecillas, Ramón; Moya, José S.

    2014-01-01

    The aim of the present study was to evaluate bone loss at implants connected to abutments coated with a soda-lime glass containing silver nanoparticles, subjected to experimental peri-implantitis. Also the aging and erosion of the coating in mouth was studied. Five beagle dogs were used in the experiments. Three implants were placed in each mandible quadrant: in 2 of them, Glass/n-Ag coated abutments were connected to implant platform, 1 was covered with a Ti-mechanized abutment. Experimental peri-implantitis was induced in all implants after the submarginal placement of cotton ligatures, and three months after animals were euthanatized. Thickness and morphology of coating was studied in abutment cross-sections by SEM. Histology and histo-morphometric studies were carried on in undecalfied ground slides. After the induced peri-implantitis: 1.The abutment coating shown losing of thickness and cracking. 2. The histometry showed a significant less bone loss in the implants with glass/n-Ag coated abutments. A more symmetric cone of bone resorption was observed in the coated group. There were no significant differences in the peri-implantitis histological characteristics between both groups of implants. Within the limits of this in-vivo study, it could be affirmed that abutments coated with biocide soda-lime-glass-silver nanoparticles can reduce bone loss in experimental peri-implantitis. This achievement makes this coating a suggestive material to control peri-implantitis development and progression. PMID:24466292

  1. Degradation and biological properties of Ca-P contained micro-arc oxidation self-sealing coating on pure magnesium for bone fixation

    PubMed Central

    Wang, Weidan; Wan, Peng; Liu, Chen; Tan, Lili; Li, Weirong; Li, Lugee; Yang, Ke

    2015-01-01

    Poor corrosion resistance is one of the main disadvantages for biodegradable magnesium-based metals, especially applied for bone fixation, where there is a high demand of bio-mechanical strength and stability. Surface coating has been proved as an effective method to control the in vivo degradation. In this study a Ca-P self-sealing micro-arc oxidation (MAO) coating was studied to verify its efficacy and biological properties by in vitro and in vivo tests. It was found that the MAO coating could effectively retard the degradation according to immersion and electrochemical tests as well as 3D reconstruction by X-ray tomography after implantation. The MAO coating exhibited no toxicity and could stimulate the new bone formation. Therefore, the Ca-P self-sealing MAO coating could be a potential candidate for application of biodegradable Mg-based implant in bone fixations. PMID:26816635

  2. In vitro antimicrobial properties of silver-polysaccharide coatings on porous fiber-reinforced composites for bone implants.

    PubMed

    Nganga, Sara; Travan, Andrea; Marsich, Eleonora; Donati, Ivan; Söderling, Eva; Moritz, Niko; Paoletti, Sergio; Vallittu, Pekka K

    2013-12-01

    Biostable fiber-reinforced composite (FRC) implants prepared from bisphenol-A-dimethacrylate and triethyleneglycoldimethacrylate resin reinforced with E-glass fibers have been successfully used in cranial reconstructions in 15 patients. Recently, porous FRC structures were suggested as potential implant materials. Compared with smooth surface, porous surface allows implant incorporation via bone ingrowth, but is also a subject to bacterial attachment. Non-cytotoxic silver-polysaccharide nanocomposite coatings may provide a way to decrease the risk of bacterial contamination of porous FRC structures. This study is focused on the in vitro characterization of the effect porosity on the antimicrobial efficiency of the coatings against Staphylococcus aureus and Pseudomonas aeruginosa by a series of microbiological tests (initial adhesion, antimicrobial efficacy, and biofilm formation). Characterization included confocal laser scanning microscopy and scanning electron microscopy. The effect of porosity on the initial attachment of S. aureus was pronounced, but in the case of P. aeruginosa the effect was negligible. There were no significant effects of the coatings on the initial bacterial attachment. In the antimicrobial efficacy test, the coatings were potent against both strains regardless of the sample morphology. In the biofilm tests, there were no clear effects either of morphology or of the coating. Further coating development is foreseen to achieve a longer-term antimicrobial effect to inhibiting bacterial implant colonization.

  3. New approach to bone tissue engineering: simultaneous application of hydroxyapatite and bioactive glass coated on a poly(L-lactic acid) scaffold.

    PubMed

    Dinarvand, Peyman; Seyedjafari, Ehsan; Shafiee, Abbas; Jandaghi, Ali Babaei; Doostmohammadi, Ali; Fathi, Mohammad Hossein; Farhadian, Shirin; Soleimani, Masoud

    2011-11-01

    A combination of bioceramics and polymeric nanofibers holds promising potential for bone tissue engineering applications. In the present study, hydroxyapatite (HA), bioactive glass (BG), and tricalcium phosphate (TCP) particles were coated on the surface of electrospun poly(L-lactic acid) (PLLA) nanofibers, and the capacity of the PLLA, BG-PLLA, HA-PLLA, HA-BG-PLLA, and TCP-PLLA scaffolds for bone regeneration was investigated in rat critical-size defects using digital mammography, multislice spiral-computed tomography (MSCT) imaging, and histological analysis. Electrospun scaffolds exhibited a nanofibrous structure with a homogeneous distribution of bioceramics along the surface of PLLA nanofibers. A total of 8 weeks after implantation, no sign of complication or inflammation was observed at the site of the calvarial bone defect. On the basis of imaging analysis, a higher level of bone reconstruction was observed in the animals receiving HA-, BG-, and TCP-coated scaffolds compared to an untreated control group. In addition, simultaneous coating of HA and BG induced the highest regeneration among all groups. Histological staining confirmed these findings and also showed an efficient osseointegration in HA-BG-coated nanofibers. On the whole, it was demonstrated that nanofibrous structures could serve as an appropriate support to guide the healing process, and coating their surface with bioceramics enhanced bone reconstruction. These bioceramic-coated scaffolds can be used as new bone-graft substitutes capable of efficiently inducing osteoconduction and osseointegration in orthopedic fractures and defects.

  4. The effect of surface demineralization of cortical bone allograft on the properties of recombinant adeno-associated virus coatings

    PubMed Central

    Yazici, Cemal; Yanoso, Laura; Xie, Chao; Reynolds, David G.; Jude Samulski, R.; Samulski, Jade; Yannariello-Brown, Judith; Gertzman, Arthur A.; Zhang, Xinping; Awad, Hani A.; Schwarz, Edward M.

    2008-01-01

    Freeze-dried recombinant adeno-associated virus (rAAV) coated structural allografts have emerged as an approach to engender necrotic cortical bone with host factors that will persist for weeks following surgery to facilitate revascularization, osteointegration, and remodeling. However, one major limitation is the nonporous cortical surface that prohibits uniform distribution of the rAAV coating prior to freeze-drying. To overcome this we have developed a demineralization method to increase surface absorbance while retaining the structural integrity of the allograft. Demineralized bone wafers (DBW) made from human femoral allograft rings demonstrated a significant 21.1 % (73.6 ± 3.9 % vs. 52.5 ± 2.6 %; p<0.001) increase in percent surface area coating versus mineralized controls. Co-incubation of rAAV-luciferase (rAAV-Luc) coated DBW with a monolayer of C3H10T1/2 cells in culture led to peak luciferase levels that were not significantly different from soluble rAAV-Luc controls (p>0.05), although the peaks occurred at 60hrs and 12hrs, respectively. To assess the transduction efficiency of rAAV-Luc coated DBW in vivo, we first performed a dose response with allografts containing 107, 109 or 1010 particles that were surgically implanted into the quadriceps of mice, and assayed by in vivo bioluminescence imaging (BLI) on days 1, 3, 5, 7, 10, 14, and 21. The results demonstrated a dose response in which the DBW coated with 1010 rAAV-Luc particles achieved peak gene expression levels on day 3, which persisted until day 21, and was significantly greater than the 107 dose throughout this time period (p<0.01). A direct comparison of mineralized versus DBW coated with 1010 rAAV-Luc particles failed to demonstrate any significant differences in transduction kinetics or efficiency in vivo. Thus, surface demineralization of human cortical bone allograft increase its absorbance for uniform rAAV coating, without affecting vector transduction efficiency. PMID:18590929

  5. Selection of highly osteogenic and chondrogenic cells from bone marrow stromal cells in biocompatible polymer-coated plates.

    PubMed

    Liu, G; Iwata, K; Ogasawara, T; Watanabe, J; Fukazawa, K; Ishihara, K; Asawa, Y; Fujihara, Y; Chung, U-L; Moro, T; Takatori, Y; Takato, T; Nakamura, K; Kawaguchi, H; Hoshi, K

    2010-03-15

    To enrich the subpopulation that preserves self-renewal and multipotentiality from conventionally prepared bone marrow stromal cells (MSCs), we attempted to use 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer-coated plates that selected the MSCs with strong adhesion ability and evaluated the proliferation ability or osteogenic/chondrogenic potential of the MPC polymer-selected MSCs. The number of MSCs that were attached to the MPC polymer-coated plates decreased with an increase in the density of MPC unit (0-10%), whereas no significant difference in the proliferation ability was seen among these cells. The surface epitopes of CD29, CD44, CD105, and CD166, and not CD34 or CD45, were detectable in the cells of all MPC polymer-coated plates, implying that they belong to the MSC category. In the osteogenic and chondrogenic induction, the MSCs selected by the 2-5% MPC unit composition showed higher expression levels of osteoblastic and chondrocytic markers (COL1A1/ALP, or COL2A1/COL10A1/Sox9) at passage 2, compared with those of 0-1% or even 10% MPC unit composition, while the enhanced effects continued by passage 5. The selection based on the adequate cell adhesiveness by the MPC polymer-coated plates could improve the osteogenic and chondrogenic potential of MSCs, which would provide cell sources that can be used to treat the more severe and various bone/cartilage diseases.

  6. Coatings.

    ERIC Educational Resources Information Center

    Anderson, Dennis G.

    1989-01-01

    This review covers analytical techniques applicable to the examination of coatings, raw materials, and substrates upon which coatings are placed. Techniques include chemical and electrochemical methods, chromatography, spectroscopy, thermal analysis, microscopy, and miscellaneous techniques. (MVL)

  7. Calcium phosphate fibers coated with collagen: In vivo evaluation of the effects on bone repair.

    PubMed

    Ueno, Fabio Roberto; Kido, Hueliton Wilian; Granito, Renata Neves; Gabbai-Armelin, Paulo Roberto; Magri, Angela Maria Paiva; Fernandes, Kelly Rosseti; da Silva, Antonio Carlos; Braga, Francisco José Correa; Renno, Ana Claudia Muniz

    2016-08-12

    The aim of this study was to assess the characteristics of the CaP/Col composites, in powder and fiber form, via scanning electron microscopy (SEM), pH and calcium release evaluation after immersion in SBF and to evaluate the performance of these materials on the bone repair process in a tibial bone defect model. For this, four different formulations (CaP powder - CaPp, CaP powder with collagen - CaPp/Col, CaP fibers - CaPf and CaP fibers with collagen - CaPf/Col) were developed. SEM images indicated that both material forms were successfully coated with collagen and that CaPp and CaPf presented HCA precursor crystals on their surface. Although presenting different forms, FTIR analysis indicated that CaPp and CaPf maintained the characteristic peaks for this class of material. Additionally, the calcium assay study demonstrated a higher Ca uptake for CaPp compared to CaPf for up to 5 days. Furthermore, pH measurements revealed that the collagen coating prevented the acidification of the medium, leading to higher pH values for CaPp/Col and CaPf/Col. The histological analysis showed that CaPf/Col demonstrated a higher amount of newly formed bone in the region of the defect and a reduced presence of material. In summary, the results indicated that the fibrous CaP enriched with the organic part (collagen) glassy scaffold presented good degradability and bone-forming properties and also supported Runx2 and RANKL expression. These results show that the present CaP/Col fibrous composite may be used as a bone graft for inducing bone repair.

  8. Comparison between alkali heat treatment and sprayed hydroxyapatite coating on thermally-sprayed rough Ti surface in rabbit model: Effects on bone-bonding ability and osteoconductivity.

    PubMed

    Kawai, Toshiyuki; Takemoto, Mitsuru; Fujibayashi, Shunsuke; Tanaka, Masashi; Akiyama, Haruhiko; Nakamura, Takashi; Matsuda, Shuichi

    2015-07-01

    In this study, we investigated the effect of different surface treatments (hydroxyapatite (HA) coating, alkali heat treatment, and no treatment) on the ability of bone to bond to a rough arc-sprayed Ti metal surface, using rabbit models. The bone-to-implant contacts for untreated, HA-coated, and alkali heat-treated implants were 21.2%, 72.1%, and 33.8% at 4 weeks, 21.8%, 70.9%, and 30.0% at 8 weeks, and 16.3%, 70.2%, and 29.9% at 16 weeks, respectively (n = 8). HA -coated implants showed significantly higher bone-to-implant contacts than the untreated and alkali heat-treated implants at all the time point, whereas alkali heat-treated implants showed significantly higher bone-to-implant contacts than untreated implants at 4 and 16 weeks. The failure loads in a mechanical test for untreated, HA coated, alkali heat-treated plates were 65.4 N, 70.7 N, and 90.8 N at 4 weeks, 76.1 N, 64.7 N, and 104.8 N at 8 weeks and 88.7 N, 92.6 N, and 118.5 N at 16 weeks, respectively (n = 8). The alkali heat-treated plates showed significantly higher failure loads than HA-coated plates at 8 and 16 weeks. The difference between HA-coated plates and untreated plates were not statistically significant at any time point. Thus HA coating, although it enables high bone-to-implant contact, may not enhance the bone-bonding properties of thermally-sprayed rough Ti metal surfaces. In contrast, alkali heat treatment can be successfully applied to thermally-sprayed Ti metal to enhance both bone-to-implant contact and bone-bonding strength.

  9. The role of nano-sized manganese coatings on bone char in removing arsenic(V) from solution: Implications for permeable reactive barrier technologies.

    PubMed

    Liu, Jing; He, Lile; Dong, Faqin; Hudson-Edwards, Karen A

    2016-06-01

    Although the removal of arsenic(V) (As(V)) from solution can be improved by forming metal-bearing coatings on solid media, there has been no research to date examining the relationship between the coating and As(V) sorption performance. Manganese-coated bone char samples with varying concentrations of Mn were created to investigate the adsorption and desorption of As(V) using batch and column experiments. Breakthrough curves were obtained by fitting the Convection-Diffusion Equation (CDE), and retardation factors were used to quantify the effects of the Mn coatings on the retention of As(V). Uncoated bone char has a higher retention factor (44.7) than bone char with 0.465 mg/g of Mn (22.0), but bone char samples with between 5.02 mg/g and 14.5 mg/g Mn have significantly higher retention factors (56.8-246). The relationship between retardation factor (Y) and Mn concentration (X) is Y = 15.1 X + 19.8. Between 0.2% and 0.6% of the sorbed As is desorbed from the Mn-coated bone char at an initial pH value of 4, compared to 30% from the uncoated bone char. The ability of the Mn-coated bone char to neutralize solutions increases with increased amounts of Mn on the char. The results suggest that using Mn-coated bone char in Permeable Reactive Barriers would be an effective method for remediating As(V)-bearing solutions such as acid mine drainage.

  10. Efficacy of a small cell-binding peptide coated hydroxyapatite substitute on bone formation and implant fixation in sheep.

    PubMed

    Ding, Ming; Andreasen, Christina M; Dencker, Mads L; Jensen, Anders E; Theilgaard, Naseem; Overgaard, Søren

    2015-04-01

    Cylindrical critical size defects were created at the distal femoral condyles bilaterally of eight female adult sheep. Titanium implants with 2-mm concentric gaps were inserted and the gaps were filled with one of the four materials: allograft; a synthetic 15-amino acid cell-binding peptide coated hydroxyapatite (ABM/P-15); hydroxyapatite + βtricalciumphosphate+ Poly-Lactic-Acid (HA/βTCP-PDLLA); or ABM/P-15+HA/βTCP-PDLLA. After nine weeks, bone-implant blocks were harvested and sectioned for micro-CT scanning, push-out test, and histomorphometry. Significant bone formation and implant fixation could be observed in all four groups. Interestingly, the microarchitecture of the ABM/P-15 group was significantly different from the control group. Tissue volume fraction and thickness were significantly greater in the ABM/P-15 group than in the allograft group. Bone formation and bone ingrowth to porous titanium implant were not significantly different among the four groups. The ABM/P-15 group had similar shear mechanical properties on implant fixation as the allograft group. Adding HA/βTCP-PDLLA to ABM/P-15 did not significantly change these parameters. This study revealed that ABM/P-15 had significantly bone formation in concentric gap, and its enhancements on bone formation and implant fixation were at least as good as allograft. It is suggested that ABM/P-15 might be a good alternative biomaterial for bone implant fixation in this well-validated critical-size defect gap model in sheep. Nevertheless, future clinical researches should focus on prospective, randomized, controlled trials in order to fully elucidate whether ABM/P-15 could be a feasible candidate for bone substitute material in orthopedic practices.

  11. Anti-Leukemia Activity of In Vitro-Expanded Human Gamma Delta T Cells in a Xenogeneic Ph+ Leukemia Model

    PubMed Central

    Siegers, Gabrielle M.; Felizardo, Tania C.; Mathieson, A. Mark; Kosaka, Yoko; Wang, Xing-Hua; Medin, Jeffrey A.; Keating, Armand

    2011-01-01

    Gamma delta T cells (GDTc) lyse a variety of hematological and solid tumour cells in vitro and in vivo, and are thus promising candidates for cellular immunotherapy. We have developed a protocol to expand human GDTc in vitro, yielding highly cytotoxic Vgamma9/Vdelta2 CD27/CD45RA double negative effector memory cells. These cells express CD16, CD45RO, CD56, CD95 and NKG2D. Flow cytometric, clonogenic, and chromium release assays confirmed their specific cytotoxicity against Ph+ cell lines in vitro. We have generated a fluorescent and bioluminescent Ph+ cell line, EM-2eGFPluc, and established a novel xenogeneic leukemia model. Intravenous injection of EM-2eGFPluc into NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) mice resulted in significant dose-dependent bone marrow engraftment; lower levels engrafted in blood, lung, liver and spleen. In vitro-expanded human GDTc injected intraperitoneally were found at higher levels in blood and organs compared to those injected intravenously; GDTc survived at least 33 days post-injection. In therapy experiments, we documented decreased bone marrow leukemia burden in mice treated with GDTc. Live GDTc were found in spleen and bone marrow at endpoint, suggesting the potential usefulness of this therapy. PMID:21304898

  12. Peri-implant bone formation and implant integration strength of peptide-modified p(AAM-co-EG/AAC) interpenetrating polymer network-coated titanium implants.

    PubMed

    Barber, Thomas A; Ho, James E; De Ranieri, Aladino; Virdi, Amarjit S; Sumner, Dale R; Healy, Kevin E

    2007-02-01

    Interpenetrating polymer networks (IPNs) of poly (acrylamide-co-ethylene glycol/acrylic acid) functionalized with an -Arg-Gly-Asp- (RGD) containing 15 amino acid peptides, derived from rat bone sialoprotein (bsp-RGD(15), were grafted to titanium implants in an effort to modulate bone formation in the peri-implant region in the rat femoral ablation model. Bone-implant contact (BIC) and bone formation within the medullary canal were determined using microcomputed tomography at 2 and 4 weeks postimplantation. BIC for bsp-RGD(15)-IPN implants was enhanced relative to hydroxyapatite tricalcium phosphate (HA-TCP) coated implants, but was similar to all other groups. Aggregate bone formation neither indicated a dose-dependent effect of bsp-RGD(15) nor a meaningful trend. Mechanical testing of implant fixation revealed that only the HA-TCP coated implants supported significant (>1 MPa) interfacial shear strength, despite exhibiting lower overall BIC, an indication that bone ingrowth into the rougher coating was the primary mode of implant fixation. While no evidence was found to support the hypothesis that bsp-RGD(15)-modified IPN coated implants significantly impacted bone-implant bonding, these results point to the lack of correlation between in vitro studies employing primary osteoblasts and in vivo wound healing in the peri-implant region.

  13. Chub mackerel gonads support colonization, survival, and proliferation of intraperitoneally transplanted xenogenic germ cells.

    PubMed

    Yazawa, Ryosuke; Takeuchi, Yutaka; Higuchi, Kentaro; Yatabe, Takashi; Kabeya, Naoki; Yoshizaki, Goro

    2010-05-01

    The production of xenogenic gametes from large-bodied, commercially important marine fish species in closely related smaller host fish species with short generation times may enable rapid and simple seed production of the target species. As a first step toward this goal, we assessed the suitability of chub mackerel, Scomber japonicus, as a small-bodied recipient species for xenogenic spermatogonial transplantation. Histological observation of the early gonadal development of chub mackerel larvae and transplantation of fluorescent-labeled spermatogonia from Nibe croaker, Nibea mitsukurii, revealed that 5.3-mm chub mackerel larvae were suitable recipients for successful transplantation. Intraperitoneally transplanted xenogenic spermatogonia efficiently colonized the gonads of these recipient larvae, and donor-derived Nibe croaker germ cells proliferated rapidly soon after colonization. Moreover, gonadal soma-derived growth factor (gsdf) mRNA, a gonadal somatic cell marker, was expressed in recipient-derived cells surrounding the incorporated donor-derived germ cells, suggesting that donor-derived germ cells had settled at an appropriate location in the recipient gonad. Our data show that xenogenic spermatogonial transplantation was successful in chub mackerel and that the somatic microenvironment of the chub mackerel gonad can support the colonization, survival, and proliferation of intraperitoneally transplanted xenogenic germ cells derived from a donor species of a different taxonomic family.

  14. Poly-ε-caprolactone Coated and Functionalized Porous Titanium and Magnesium Implants for Enhancing Angiogenesis in Critically Sized Bone Defects.

    PubMed

    Roland, Laura; Grau, Michael; Matena, Julia; Teske, Michael; Gieseke, Matthias; Kampmann, Andreas; Beyerbach, Martin; Murua Escobar, Hugo; Haferkamp, Heinz; Gellrich, Nils-Claudius; Nolte, Ingo

    2015-12-22

    For healing of critically sized bone defects, biocompatible and angiogenesis supporting implants are favorable. Murine osteoblasts showed equal proliferation behavior on the polymers poly-ε-caprolactone (PCL) and poly-(3-hydroxybutyrate)/poly-(4-hydroxybutyrate) (P(3HB)/P(4HB)). As vitality was significantly better for PCL, it was chosen as a suitable coating material for further experiments. Titanium implants with 600 µm pore size were evaluated and found to be a good implant material for bone, as primary osteoblasts showed a vitality and proliferation onto the implants comparable to well bottom (WB). Pure porous titanium implants and PCL coated porous titanium implants were compared using Live Cell Imaging (LCI) with Green fluorescent protein (GFP)-osteoblasts. Cell count and cell covered area did not differ between the implants after seven days. To improve ingrowth of blood vessels into porous implants, proangiogenic factors like Vascular Endothelial Growth Factor (VEGF) and High Mobility Group Box 1 (HMGB1) were incorporated into PCL coated, porous titanium and magnesium implants. An angiogenesis assay was performed to establish an in vitro method for evaluating the impact of metallic implants on angiogenesis to reduce and refine animal experiments in future. Incorporated concentrations of proangiogenic factors were probably too low, as they did not lead to any effect. Magnesium implants did not yield evaluable results, as they led to pH increase and subsequent cell death.

  15. Poly-ε-caprolactone Coated and Functionalized Porous Titanium and Magnesium Implants for Enhancing Angiogenesis in Critically Sized Bone Defects

    PubMed Central

    Roland, Laura; Grau, Michael; Matena, Julia; Teske, Michael; Gieseke, Matthias; Kampmann, Andreas; Beyerbach, Martin; Murua Escobar, Hugo; Haferkamp, Heinz; Gellrich, Nils-Claudius; Nolte, Ingo

    2015-01-01

    For healing of critically sized bone defects, biocompatible and angiogenesis supporting implants are favorable. Murine osteoblasts showed equal proliferation behavior on the polymers poly-ε-caprolactone (PCL) and poly-(3-hydroxybutyrate)/poly-(4-hydroxybutyrate) (P(3HB)/P(4HB)). As vitality was significantly better for PCL, it was chosen as a suitable coating material for further experiments. Titanium implants with 600 µm pore size were evaluated and found to be a good implant material for bone, as primary osteoblasts showed a vitality and proliferation onto the implants comparable to well bottom (WB). Pure porous titanium implants and PCL coated porous titanium implants were compared using Live Cell Imaging (LCI) with Green fluorescent protein (GFP)-osteoblasts. Cell count and cell covered area did not differ between the implants after seven days. To improve ingrowth of blood vessels into porous implants, proangiogenic factors like Vascular Endothelial Growth Factor (VEGF) and High Mobility Group Box 1 (HMGB1) were incorporated into PCL coated, porous titanium and magnesium implants. An angiogenesis assay was performed to establish an in vitro method for evaluating the impact of metallic implants on angiogenesis to reduce and refine animal experiments in future. Incorporated concentrations of proangiogenic factors were probably too low, as they did not lead to any effect. Magnesium implants did not yield evaluable results, as they led to pH increase and subsequent cell death. PMID:26703586

  16. Bone

    NASA Astrophysics Data System (ADS)

    Helmberger, Thomas K.; Hoffmann, Ralf-Thorsten

    The typical clinical signs in bone tumours are pain, destruction and destabilization, immobilization, neurologic deficits, and finally functional impairment. Primary malignant bone tumours are a rare entity, accounting for about 0.2% of all malignancies. Also benign primary bone tumours are in total rare and mostly asymptomatic. The most common symptomatic benign bone tumour is osteoid osteoma with an incidence of 1:2000.

  17. Silk coating on a bioactive ceramic scaffold for bone regeneration: effective enhancement of mechanical and in vitro osteogenic properties towards load-bearing applications.

    PubMed

    Li, Jiao Jiao; Roohani-Esfahani, Seyed-Iman; Kim, Kyungsook; Kaplan, David L; Zreiqat, Hala

    2015-07-24

    Bioactive ceramic scaffolds represent competitive choices for clinical bone reconstruction, but their widespread use is restricted by inherent brittleness and weak mechanical performance under load. This study reports the development of strong and tough bioactive scaffolds suitable for use in load-bearing bone reconstruction. A strong and bioactive ceramic scaffold (strontium-hardystonite-gahnite) is combined with single and multiple coating layers of silk fibroin to enhance its toughness, producing composite scaffolds which match the mechanical properties of cancellous bone and show enhanced capacity to promote in vitro osteogenesis. Also reported for the first time is a comparison of the coating effects obtained when a polymeric material is coated on ceramic scaffolds with differing microstructures, namely the strontium-hardystonite-gahnite scaffold with high-density struts as opposed to a conventional ceramic scaffold, such as biphasic calcium phosphate, with low-density struts. The results show that silk coating on a unique ceramic scaffold can lead to simple and effective enhancement of its mechanical and biological properties to suit a wider range of applications in clinical bone reconstruction, and also establish the influence of ceramic microstructure on the effectiveness of silk coating as a method of reinforcement when applied to different types of ceramic bone graft substitutes. Copyright © 2015 John Wiley & Sons, Ltd.

  18. Polycaprolactone-Coated 3D Printed Tricalcium Phosphate Scaffolds for Bone Tissue Engineering: In Vitro Alendronate Release Behavior and Local Delivery Effect on In Vivo Osteogenesis

    PubMed Central

    2015-01-01

    The aim of this work was to evaluate the effect of in vitro alendronate (AD) release behavior through polycaprolactone (PCL) coating on in vivo bone formation using PCL-coated 3D printed interconnected porous tricalcium phosphate (TCP) scaffolds. Higher AD and Ca2+ ion release was observed at lower pH (5.0) than that at higher pH (7.4). AD and Ca2+ release, surface morphology, and phase analysis after release indicated a matrix degradation dominated AD release caused by TCP dissolution. PCL coating showed its effectiveness for controlled and sustained AD release. Six different scaffold compositions, namely, (i) TCP (bare TCP), (ii) TCP + AD (AD-coated TCP), (iii) TCP + PCL (PCL-coated TCP), (iv) TCP + PCL + AD, (v) TCP + AD + PCL, and (vi) TCP + AD + PCL + AD were tested in the distal femoral defect of Sprague–Dawley rats for 6 and 10 weeks. An excellent bone formation inside the micro and macro pores of the scaffolds was observed from histomorphology. Histomorphometric analysis revealed maximum new bone formation in TCP + AD + PCL scaffolds after 6 weeks. No adverse effect of PCL on bioactivity of TCP and in vivo bone formation was observed. All scaffolds with AD showed higher bone formation and reduced TRAP (tartrate resistant acid phosphatase) positive cells activity compared to bare TCP and TCP coated with only PCL. Bare TCP scaffolds showed the highest TRAP positive cells activity followed by TCP + PCL scaffolds, whereas TCP + AD scaffolds showed the lowest TRAP activity. A higher TRAP positive cells activity was observed in TCP + AD + PCL compared to TCP + AD scaffolds after 6 weeks. Our results show that in vivo local AD delivery from PCL-coated 3DP TCP scaffolds could further induce increased early bone formation. PMID:24826838

  19. Mechanical properties and drug release behavior of PCL/zein coated 45S5 bioactive glass scaffolds for bone tissue engineering application.

    PubMed

    Fereshteh, Zeinab; Nooeaid, Patcharakamon; Fathi, Mohammadhossein; Bagri, Akbar; Boccaccini, Aldo R

    2015-09-01

    This article presents data related to the research article entitled "The effect of coating type on mechanical properties and controlled drug release of PCL/zein coated 45S5 bioactive glass scaffolds for bone tissue engineering" [1]. We provide data on mechanical properties, in vitro bioactivity and drug release of bioactive glass (BG) scaffolds coated by poly (ε-caprolactone) (PCL) and zein used as a controlled release device for tetracycline hydrochloride (TCH). By coating the BG scaffolds with PCL or PCL/zein blend the mechanical properties of the scaffolds were substantially improved, i.e., the compressive strength increased from 0.004±0.001 MPa (uncoated BG scaffolds) to 0.15±0.02 MPa (PCL/zein coated BG scaffolds). A dense bone-like apatite layer formed on the surface of PCL/zein coated scaffolds immersed for 14 days in simulated body fluid (SBF). The data describe control of drug release and in vitro degradation behavior of coating by engineering the concentration of zein. Thus, the developed scaffolds exhibit attractive properties for application in bone tissue engineering research.

  20. Mechanical properties and drug release behavior of PCL/zein coated 45S5 bioactive glass scaffolds for bone tissue engineering application

    PubMed Central

    Fereshteh, Zeinab; Nooeaid, Patcharakamon; Fathi, Mohammadhossein; Bagri, Akbar; Boccaccini, Aldo R.

    2015-01-01

    This article presents data related to the research article entitled “The effect of coating type on mechanical properties and controlled drug release of PCL/zein coated 45S5 bioactive glass scaffolds for bone tissue engineering” [1]. We provide data on mechanical properties, in vitro bioactivity and drug release of bioactive glass (BG) scaffolds coated by poly (ε-caprolactone) (PCL) and zein used as a controlled release device for tetracycline hydrochloride (TCH). By coating the BG scaffolds with PCL or PCL/zein blend the mechanical properties of the scaffolds were substantially improved, i.e., the compressive strength increased from 0.004±0.001 MPa (uncoated BG scaffolds) to 0.15±0.02 MPa (PCL/zein coated BG scaffolds). A dense bone-like apatite layer formed on the surface of PCL/zein coated scaffolds immersed for 14 days in simulated body fluid (SBF). The data describe control of drug release and in vitro degradation behavior of coating by engineering the concentration of zein. Thus, the developed scaffolds exhibit attractive properties for application in bone tissue engineering research. PMID:26966716

  1. Cellulose Nanocrystals--Bioactive Glass Hybrid Coating as Bone Substitutes by Electrophoretic Co-deposition: In Situ Control of Mineralization of Bioactive Glass and Enhancement of Osteoblastic Performance.

    PubMed

    Chen, Qiang; Garcia, Rosalina Pérez; Munoz, Josemari; Pérez de Larraya, Uxua; Garmendia, Nere; Yao, Qingqing; Boccaccini, Aldo R

    2015-11-11

    Surface functionalization of orthopedic implants is being intensively investigated to strengthen bone-to-implant contact and accelerate bone healing process. A hybrid coating, consisting of 45S5 bioactive glass (BG) individually wrapped and interconnected with fibrous cellulose nanocrystals (CNCs), is deposited on 316L stainless steel from aqueous suspension by a one-step electrophoretic deposition (EPD) process. Apart from the codeposition mechanism elucidated by means of zeta-potential and scanning electron microscopy measurements, in vitro characterization of the deposited CNCs-BG coating in simulated body fluid reveals an extremely rapid mineralization of BG particles on the coating (e.g., the formation of hydroxyapatite crystals layer after 0.5 day). A series of comparative trials and characterization methods were carried out to comprehensively understand the mineralization process of BG interacting with CNCs. Furthermore, key factors for satisfying the applicability of an implant coating such as coating composition, surface topography, and adhesion strength were quantitatively investigated as a function of mineralization time. Cell culture studies (using MC3T3-E1) indicate that the presence of CNCs-BG coating substantially accelerated cell attachment, spreading, proliferation, differentiation, and mineralization of extracellular matrix. This study has confirmed the capability of CNCs to enhance and regulate the bioactivity of BG particles, leading to mineralized CNCs-BG hybrids for improved bone implant coatings.

  2. Bone regeneration in critical bone defects using three-dimensionally printed β-tricalcium phosphate/hydroxyapatite scaffolds is enhanced by coating scaffolds with either dipyridamole or BMP-2.

    PubMed

    Ishack, Stephanie; Mediero, Aranzazu; Wilder, Tuere; Ricci, John L; Cronstein, Bruce N

    2017-02-01

    Bone defects resulting from trauma or infection need timely and effective treatments to restore damaged bone. Using specialized three-dimensional (3D) printing technology we have created custom 3D scaffolds of hydroxyapatite (HA)/beta-tri-calcium phosphate (β-TCP) to promote bone repair. To further enhance bone regeneration we have coated the scaffolds with dipyridamole, an agent that increases local adenosine levels by blocking cellular uptake of adenosine. Nearly 15% HA:85% β-TCP scaffolds were designed using Robocad software, fabricated using a 3D Robocasting system, and sintered at 1100°C for 4 h. Scaffolds were coated with BMP-2 (200 ng mL(-1) ), dypiridamole 100 µM or saline and implanted in C57B6 and adenosine A2A receptor knockout (A2AKO) mice with 3 mm cranial critical bone defects for 2-8 weeks. Dipyridamole release from scaffold was assayed spectrophotometrically. MicroCT and histological analysis were performed. Micro-computed tomography (microCT) showed significant bone formation and remodeling in HA/β-TCP-dipyridamole and HA/β-TCP-BMP-2 scaffolds when compared to scaffolds immersed in vehicle at 2, 4, and 8 weeks (n = 5 per group; p ≤ 0.05, p ≤ 0.05, and p ≤ 0.01, respectively). Histological analysis showed increased bone formation and a trend toward increased remodeling in HA/β-TCP- dipyridamole and HA/β-TCP-BMP-2 scaffolds. Coating scaffolds with dipyridamole did not enhance bone regeneration in A2AKO mice. In conclusion, scaffolds printed with HA/β-TCP promote bone regeneration in critical bone defects and coating these scaffolds with agents that stimulate A2A receptors and growth factors can further enhance bone regeneration. These coated scaffolds may be very useful for treating critical bone defects due to trauma, infection or other causes. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 366-375, 2017.

  3. Improving the osteointegration and bone-implant interface by incorporation of bioactive particles in sol-gel coatings of stainless steel implants.

    PubMed

    Ballarre, Josefina; Manjubala, Inderchand; Schreiner, Wido H; Orellano, Juan Carlos; Fratzl, Peter; Ceré, Silvia

    2010-04-01

    In this study, we report a hybrid organic-inorganic TEOS-MTES (tetraethylorthosilicate-methyltriethoxysilane) sol-gel-made coating as a potential solution to improve the in vivo performance of AISI 316L stainless steel, which is used as permanent bone implant material. These coatings act as barriers for ion migration, promoting the bioactivity of the implant surface. The addition of SiO(2) colloidal particles to the TEOS-MTES sol (10 or 30 mol.%) leads to thicker films and also acts as a film reinforcement. Also, the addition of bioactive glass-ceramic particles is considered responsible for enhancing osseointegration. In vitro assays for bioactivity in simulated body fluid showed the presence of crystalline hydroxyapatite (HA) crystals on the surface of the double coating with 10mol.% SiO(2) samples on stainless steel after 30 days of immersion. The HA crystal lattice parameters are slightly different from stoichiometric HA. In vivo implantation experiments were carried out in a rat model to observe the osteointegration of the coated implants. The coatings promote the development of newly formed bone in the periphery of the implant, in both the remodellation zone and the marrow zone. The quality of the newly formed bone was assessed for mechanical and structural integrity by nanoindentation and small-angle X-ray scattering experiments. The different amount of colloidal silica present in the inner layer of the coating slightly affects the material quality of the newly formed bone but the nanoindentation results reveal that the lower amount of silica in the coating leads to mechanical properties similar to cortical bone.

  4. Coating of biodegradable magnesium alloy bone implants using nanostructured diopside (CaMgSi2O6)

    NASA Astrophysics Data System (ADS)

    Razavi, Mehdi; Fathi, Mohammadhossein; Savabi, Omid; Beni, Batoul Hashemi; Razavi, Seyed Mohammad; Vashaee, Daryoosh; Tayebi, Lobat

    2014-01-01

    Magnesium alloys with their biodegradable characteristic can be a very good candidate to be used in orthopedic implants. However, magnesium alloys may corrode and degrade too fast for applications in the bone healing procedure. In order to enhance the corrosion resistance and the in vitro bioactivity of a magnesium alloy, a nanostructured diopside (CaMgSi2O6) film was coated on AZ91 magnesium alloy through combined micro-arc oxidation (MAO) and electrophoretic deposition (EPD) methods. The crystalline structures, morphologies and compositions of the coated and uncoated substrates were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy. Polarization, electrochemical impedance spectroscopy, and immersion test in simulated body fluid (SBF) were employed to evaluate the corrosion resistance and the in vitro bioactivity of the samples. The results of our investigation showed that the nanostructured diopside coating deposited on the MAO layer increases the corrosion resistance and improves the in vitro bioactivity of the biodegradable magnesium alloy.

  5. Biological Response of Human Bone Marrow-Derived Mesenchymal Stem Cells to Commercial Tantalum Coatings with Microscale and Nanoscale Surface Topographies

    NASA Astrophysics Data System (ADS)

    Skoog, Shelby A.; Kumar, Girish; Goering, Peter L.; Williams, Brian; Stiglich, Jack; Narayan, Roger J.

    2016-06-01

    Tantalum is a promising orthopaedic implant coating material due to its robust mechanical properties, corrosion resistance, and excellent biocompatibility. Previous studies have demonstrated improved biocompatibility and tissue integration of surface-treated tantalum coatings compared to untreated tantalum. Surface modification of tantalum coatings with biologically inspired microscale and nanoscale features may be used to evoke optimal tissue responses. The goal of this study was to evaluate commercial tantalum coatings with nanoscale, sub-microscale, and microscale surface topographies for orthopaedic and dental applications using human bone marrow-derived mesenchymal stem cells (hBMSCs). Tantalum coatings with different microscale and nanoscale surface topographies were fabricated using a diffusion process or chemical vapor deposition. Biological evaluation of the tantalum coatings using hBMSCs showed that tantalum coatings promote cellular adhesion and growth. Furthermore, hBMSC adhesion to the tantalum coatings was dependent on surface feature characteristics, with enhanced cell adhesion on sub-micrometer- and micrometer-sized surface topographies compared to hybrid nano-/microstructures. Nanostructured and microstructured tantalum coatings should be further evaluated to optimize the surface coating features to promote osteogenesis and enhance osseointegration of tantalum-based orthopaedic implants.

  6. Preparation of bone-implants by coating hydroxyapatite nanoparticles on self-formed titanium dioxide thin-layers on titanium metal surfaces.

    PubMed

    Wijesinghe, W P S L; Mantilaka, M M M G P G; Chathuranga Senarathna, K G; Herath, H M T U; Premachandra, T N; Ranasinghe, C S K; Rajapakse, R P V J; Rajapakse, R M G; Edirisinghe, Mohan; Mahalingam, S; Bandara, I M C C D; Singh, Sanjleena

    2016-06-01

    Preparation of hydroxyapatite coated custom-made metallic bone-implants is very important for the replacement of injured bones of the body. Furthermore, these bone-implants are more stable under the corrosive environment of the body and biocompatible than bone-implants made up of pure metals and metal alloys. Herein, we describe a novel, simple and low-cost technique to prepare biocompatible hydroxyapatite coated titanium metal (TiM) implants through growth of self-formed TiO2 thin-layer (SFTL) on TiM via a heat treatment process. SFTL acts as a surface binder of HA nanoparticles in order to produce HA coated implants. Colloidal HA nanorods prepared by a novel surfactant-assisted synthesis method, have been coated on SFTL via atomized spray pyrolysis (ASP) technique. The corrosion behavior of the bare and surface-modified TiM (SMTiM) in a simulated body fluid (SBF) medium is also studied. The highest corrosion rate is found to be for the bare TiM plate, but the corrosion rate has been reduced with the heat-treatment of TiM due to the formation of SFTL. The lowest corrosion rate is recorded for the implant prepared by heat treatment of TiM at 700 °C. The HA-coating further assists in the passivation of the TiM in the SBF medium. Both SMTiM and HA coated SMTiM are noncytotoxic against osteoblast-like (HOS) cells and are in high-bioactivity. The overall production process of bone-implant described in this paper is in high economic value.

  7. Antibiotic-loaded plaster of Paris implants coated with poly lactide-co-glycolide as a controlled release delivery system for the treatment of bone infections.

    PubMed

    Benoit, M A; Mousset, B; Delloye, C; Bouillet, R; Gillard, J

    1997-01-01

    Plaster of Paris implants containing vancomycin (60 mg/g of carrier) were prepared in order to be used as local delivery system for the treatment of bone infections. The regulation of the release rate was performed by coating the carrier with a polylactide-co-glycolide polymer composed by 10% (w/w) polyglycolic acid and 90% (w/w) racemic poly (D,L-lactic acid). The release of the antibiotic from the biodegradable matrix was evaluated in vitro. From this investigation, it is clear that the drug elution depends on the coating depth. After a burst effect occurring on the first day of the experiment, therapeutic concentrations were measured during one week when uncoated implants were used. The coating allowed decrease of the burst effect and extended efficient release to more than five weeks when the implants were embedded with six layers (162 microns) of PLA45GA10. This delivery system was implanted into the femoral condyle of rabbits. It was shown that the in vivo release was also closely regulated by the coating depth. In all bone tissues (bone marrow and cortical bone) surrounding the pellets, the drug concentration exceeded the Minimum Inhibitory Concentration for the common causative organisms of bone infections (Staphylococcus aureus) for at least four weeks without inducing serum toxic levels. Due to its cheapness, facility of use and sterilization, biocompatibility and biodegradability, plaster of Paris coated with PLA45GA10 polymer giving a controlled release of vancomycin appears to be a promising sustained release delivery system of antibiotics for the treatment of bone and joint infections.

  8. Influence of Hydroxyapatite-Coated and Growth Factor–Releasing Interference Screws on Tendon-Bone Healing in an Ovine Model

    PubMed Central

    Lu, Yan; Markel, Mark D.; Nemke, Brett; Lee, J. Sam; Graf, Ben K.; Murphy, William L.

    2014-01-01

    Purpose Our purpose was to determine whether a bioresorbable interference screw coated with a hydroxyapatite-based mineral layer designed to release an engineered peptide growth factor (linkBMP-2 [where “BMP-2” indicates bone morphogenetic protein 2]) improved tendon-bone healing compared with a screw without coating. Methods Tagged linkBMP-2 peptides were used to quantify binding efficiency and release kinetics on 9 mineral-coated BIORCI screws (Smith & Nephew, Andover, MA). Fourteen mature female sheep were used in this study. In each of the 14 sheep, each stifle was randomized to either receive a linkBMP-2–coated or uncoated interference screw (n ± 14 per treatment). The sheep were euthanized at 6 weeks after surgery. Eight sheep were subjected to biomechanical testing for peak load at failure and stiffness, and six sheep were used for histologic analysis according to a semiquantitative scoring scale. Results The linkBMP-2 molecule bound efficiently to the surface of mineral-coated interference screws. Over 80% of the initially bound linkBMP-2 was released during a 6-week time frame in vitro. Peak load at failure in the linkBMP-2–coated interference screw group (mean ± SD, 449.3 ± 84.7 N) was not significantly different from that in the uncoated group (421.0 ± 61.8 N) (P = .22). Stiffness in the linkBMP-2–coated interference screw group (157.3 ± 39.6 N/mm) was not significantly different from that in the uncoated group (140.6 ± 20.3 N/mm) (P = .12). Histologic analysis showed that the tendons in the linkBMP-2–coated interference screw group had higher scores (better) than the uncoated group. In the linkBMP-2–coated interference screw group, mesenchymal cells were present at the interface between screw and tendon, whereas these cells were not present in the uncoated group. Conclusions We found that linkBMP-2 can be bound onto a mineral-coated BIORCI interference screw surface and subsequently released from the screw surface in a sustained

  9. The use of postoperative irradiation for the prevention of heterotopic bone after total hip replacement with biologic fixation (porous coated) prosthesis: An animal model

    SciTech Connect

    Konski, A.; Weiss, C.; Rosier, R.; Poulter, C.; Pelligrini, V.; Anthony, P.; Evarts, C.M.; Richardson, M.; Henzler, M.; Rubin, P. )

    1990-04-01

    Radiation has been shown to be effective in the prevention of heterotopic bone. The exact etiology of heterotopic bone is unknown. Total hip prosthetic devices that do not depend upon bone cement for fixation have become increasingly popular. The mechanism by which the bone forms around the prosthesis is similar to the process by which fractures heal which has been shown to be sensitive to irradiation. Using a rabbit model we have undertaken a study to investigate the effect of irradiation on the bony ingrowth on porous coated implants. Forty-five rabbits had porous coated implants surgically placed in the tibiae bilaterally. Each rabbit had one tibia randomly irradiated with 1,000 cGy in 5 fractions starting on the first post-operative day. Animals were sacrificed weekly starting 2 weeks post-operatively and the tibae were sent for pullout studies. The amount of force necessary to pullout the treated tibae was statistically less than the amount of force necessary to remove the untreated tibae at 2 weeks. From 3 weeks on there was no difference in the force necessary to remove the prosthesis from the untreated or treated tibae. Histologically, the untreated tibae showed bone formation while the treated tibae did not. Because of these results, it is suggested that the treatment of patients at risk for development of heterotopic bone be modified to only include the area between the femur and pelvis avoiding treatment of the prosthetic device.

  10. Xenogeneic Bio-Root Prompts the Constructive Process Characterized by Macrophage Phenotype Polarization in Rodents and Nonhuman Primates.

    PubMed

    Li, Hui; Sun, Jingjing; Li, Jie; Yang, Hefeng; Luo, Xiangyou; Chen, Jinlong; Xie, Li; Huo, Fangjun; Zhu, Tian; Guo, Weihua; Tian, Weidong

    2017-03-01

    Tissue or organ regeneration using xenogeneic matrices is a promising approach to address the shortage of donor matrices for allotransplantation. Success of such approach has been demonstrated to correlate with macrophage-mediated fibrotic homeostasis and tissue remodeling. The previous studies have demonstrated that treated dentin matrix (TDM) could be a suitable bioactive substrate for allogeneic tooth root regeneration. This study constructed xenogeneic bioengineered tooth root (bio-root) via a combination of porcine TDM (pTDM) with allogeneic dental follicle cells (DFCs). Macrophage phenotypes are used to evaluate the remodeling process of xenogeneic bio-roots in vitro and in vivo. pTDM can facilitate odontoblast differentiation of human derived DFCs. Xenogeneic bio-roots in rat subcutaneous tissue prompt constructive response via M1 macrophage infiltration during early postimplantation stages and increase restorative M2 phenotype at later stages. After implantation of bio-roots into jaws of rhesus monkeys for six months, periodontal ligament-like fibers accompanied by macrophage polarization are observed, which are positive for COL-1, Periostin, βIII-tubulin and display such structures as fibroblasts and blood vessels. The reconstructed bio-root possesses biomechanical properties for the dissipation of masticatory forces. These results support that xenogeneic bio-root could maintain fibrotic homeostasis during remodeling process and highlight the potential application of xenogeneic matrices in regenerative medicine.

  11. Bone response to titanium implants coated with thin sputtered HA film subject to hydrothermal treatment and implanted in the canine mandible.

    PubMed

    Ozeki, K; Okuyama, Y; Fukui, Y; Aoki, H

    2006-01-01

    Hydroxyapatite (HA) was coated onto titanium implants using radio frequency magnetron sputtering. The HA films were crystallized in an autoclave tube using low temperature hydrothermal treatment. The average film thickness on the implant was 1.1 microm. HA-coated and pure-titanium implants were inserted into canine mandibles for up to 24 weeks. Forty-eight implants were placed in eight beagles. After 2, 4, 12 and 24 weeks, implants were retrieved and prepared for histological observation, and the HA film thickness was determined using energy-dispersive X-ray spectroscopy. Light microscopy revealed that, after two weeks, the bone response to the HA-coated implants was much better than to the pure titanium implants, and osteoblasts were observed at the bone-implant interface. After four weeks, the screw threads of the HA-coated implants were almost completely covered with bone. The HA film thickness rapidly decreased up to four weeks of implantation, then gently decreased, reaching 0.40+/-0.03 microm at the upper region of the implant after 12 weeks. That indicates that about 80% of the HA film had dissolved after 12 weeks of implantation. The rate of decrease in the HA film thickness was greater with increasing implant depth.

  12. Humanized mouse model for assessing the human immune response to xenogeneic and allogeneic decellularized biomaterials.

    PubMed

    Wang, Raymond M; Johnson, Todd D; He, Jingjin; Rong, Zhili; Wong, Michelle; Nigam, Vishal; Behfar, Atta; Xu, Yang; Christman, Karen L

    2017-06-01

    Current assessment of biomaterial biocompatibility is typically implemented in wild type rodent models. Unfortunately, different characteristics of the immune systems in rodents versus humans limit the capability of these models to mimic the human immune response to naturally derived biomaterials. Here we investigated the utility of humanized mice as an improved model for testing naturally derived biomaterials. Two injectable hydrogels derived from decellularized porcine or human cadaveric myocardium were compared. Three days and one week after subcutaneous injection, the hydrogels were analyzed for early and mid-phase immune responses, respectively. Immune cells in the humanized mouse model, particularly T-helper cells, responded distinctly between the xenogeneic and allogeneic biomaterials. The allogeneic extracellular matrix derived hydrogels elicited significantly reduced total, human specific, and CD4(+) T-helper cell infiltration in humanized mice compared to xenogeneic extracellular matrix hydrogels, which was not recapitulated in wild type mice. T-helper cells, in response to the allogeneic hydrogel material, were also less polarized towards a pro-remodeling Th2 phenotype compared to xenogeneic extracellular matrix hydrogels in humanized mice. In both models, both biomaterials induced the infiltration of macrophages polarized towards a M2 phenotype and T-helper cells polarized towards a Th2 phenotype. In conclusion, these studies showed the importance of testing naturally derived biomaterials in immune competent animals and the potential of utilizing this humanized mouse model for further studying human immune cell responses to biomaterials in an in vivo environment.

  13. A xenogeneic-free system generating functional human gut organoids from pluripotent stem cells

    PubMed Central

    Uchida, Hajime; Machida, Masakazu; Miura, Takumi; Kawasaki, Tomoyuki; Sasaki, Kengo; Sakamoto, Seisuke; Ohuchi, Noriaki; Kasahara, Mureo; Umezawa, Akihiro

    2017-01-01

    Functional intestines are composed of cell types from all 3 primary germ layers and are generated through a highly orchestrated and serial developmental process. Directed differentiation of human pluripotent stem cells (hPSCs) has been shown to yield gut-specific cell types; however, these structures do not reproduce critical functional interactions between cell types of different germ layers. Here, we developed a simple protocol for the generation of mature functional intestinal organoids from hPSCs under xenogeneic-free conditions. The stem cell–derived gut organoids produced here were found to contain distinct types of intestinal cells, including enterocytes, goblet cells, Paneth cells, and enteroendocrine cells, that were derived from all 3 germ layers; moreover, they demonstrated intestinal functions, including peptide absorption, and showed innervated bowel movements in response to stimulation with histamine and anticholinergic drugs. Importantly, the gut organoids obtained using this xenogeneic-free system could be stably maintained in culture for prolonged periods and were successfully engrafted in vivo. Our xenogeneic-free approach for generating gut organoids from hPSCs provides a platform for studying human intestinal diseases and for pharmacological testing. PMID:28097227

  14. ITIM-dependent negative signaling pathways for the control of cell-mediated xenogeneic immune responses.

    PubMed

    del Rio, Maria-Luisa; Seebach, Jörg D; Fernández-Renedo, Carlos; Rodriguez-Barbosa, Jose-Ignacio

    2013-01-01

    Xenotransplantation is an innovative field of research with the potential to provide us with an alternative source of organs to face the severe shortage of human organ donors. For several reasons, pigs have been chosen as the most suitable source of organs and tissues for transplantation in humans. However, porcine xenografts undergo cellular immune responses representing a major barrier to their acceptance and normal functioning. Innate and adaptive xenogeneic immunity is mediated by both the recognition of xenogeneic tissue antigens and the lack of inhibition due to molecular cross-species incompatibilities of regulatory pathways. Therefore, the delivery of immunoreceptor tyrosine-based inhibitory motif (ITIM)-dependent and related negative signals to control innate (NK cells, macrophages) and adaptive T and B cells might overcome cell-mediated xenogeneic immunity. The proof of this concept has already been achieved in vitro by the transgenic overexpression of human ligands of several inhibitory receptors in porcine cells resulting in their resistance against xenoreactivity. Consequently, several transgenic pigs expressing tissue-specific human ligands of inhibitory coreceptors (HLA-E, CD47) or soluble competitors of costimulation (belatacept) have already been generated. The development of these robust and innovative approaches to modulate human anti-pig cellular immune responses, complementary to conventional immunosuppression, will help to achieve long-term xenograft survival. In this review, we will focus on the current strategies to enhance negative signaling pathways for the regulation of undesirable cell-mediated xenoreactive immune responses.

  15. A xenogeneic-free system generating functional human gut organoids from pluripotent stem cells.

    PubMed

    Uchida, Hajime; Machida, Masakazu; Miura, Takumi; Kawasaki, Tomoyuki; Okazaki, Takuya; Sasaki, Kengo; Sakamoto, Seisuke; Ohuchi, Noriaki; Kasahara, Mureo; Umezawa, Akihiro; Akutsu, Hidenori

    2017-01-12

    Functional intestines are composed of cell types from all 3 primary germ layers and are generated through a highly orchestrated and serial developmental process. Directed differentiation of human pluripotent stem cells (hPSCs) has been shown to yield gut-specific cell types; however, these structures do not reproduce critical functional interactions between cell types of different germ layers. Here, we developed a simple protocol for the generation of mature functional intestinal organoids from hPSCs under xenogeneic-free conditions. The stem cell-derived gut organoids produced here were found to contain distinct types of intestinal cells, including enterocytes, goblet cells, Paneth cells, and enteroendocrine cells, that were derived from all 3 germ layers; moreover, they demonstrated intestinal functions, including peptide absorption, and showed innervated bowel movements in response to stimulation with histamine and anticholinergic drugs. Importantly, the gut organoids obtained using this xenogeneic-free system could be stably maintained in culture for prolonged periods and were successfully engrafted in vivo. Our xenogeneic-free approach for generating gut organoids from hPSCs provides a platform for studying human intestinal diseases and for pharmacological testing.

  16. Local delivery of parathyroid hormone-related protein-derived peptides coated onto a hydroxyapatite-based implant enhances bone regeneration in old and diabetic rats.

    PubMed

    Ardura, Juan A; Portal-Núñez, Sergio; Lozano, Daniel; Gutiérrez-Rojas, Irene; Sánchez-Salcedo, Sandra; López-Herradón, Ana; Mulero, Francisca; Villanueva-Peñacarrillo, María L; Vallet-Regí, María; Esbrit, Pedro

    2016-08-01

    Diabetes mellitus (DM) and aging are associated with bone fragility and increased fracture risk. Both (1-37) N- and (107-111) C-terminal parathyroid hormone-related protein (PTHrP) exhibit osteogenic properties. We here aimed to evaluate and compare the efficacy of either PTHrP (1-37) or PTHrP (107-111) loaded into gelatin-glutaraldehyde-coated hydroxyapatite (HA-Gel) foams to improve bone repair of a transcortical tibial defect in aging rats with or without DM, induced by streptozotocin injection at birth. Diabetic old rats showed bone structural deterioration compared to their age-matched controls. Histological and μ-computerized tomography studies showed incomplete bone repair at 4 weeks after implantation of unloaded Ha-Gel foams in the transcortical tibial defects, mainly in old rats with DM. However, enhanced defect healing, as shown by an increase of bone volume/tissue volume and trabecular and cortical thickness and decreased trabecular separation, occurred in the presence of either PTHrP peptide in the implants in old rats with or without DM. This was accompanied by newly formed bone tissue around the osteointegrated HA-Gel implant and increased gene expression of osteocalcin and vascular endothelial growth factor (bone formation and angiogenic markers, respectively), and decreased expression of Sost gene, a negative regulator of bone formation, in the healing bone area. Our findings suggest that local delivery of PTHrP (1-37) or PTHrP (107-111) from a degradable implant is an attractive strategy to improve bone regeneration in aged and diabetic subjects. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2060-2070, 2016.

  17. A poly(glycerol sebacate)-coated mesoporous bioactive glass scaffold with adjustable mechanical strength, degradation rate, controlled-release and cell behavior for bone tissue engineering.

    PubMed

    Lin, Dan; Yang, Kai; Tang, Wei; Liu, Yutong; Yuan, Yuan; Liu, Changsheng

    2015-07-01

    Various requirements in the field of tissue engineering have motivated the development of three-dimensional scaffold with adjustable physicochemical properties and biological functions. A series of multiparameter-adjustable mesoporous bioactive glass (MBG) scaffolds with uncrosslinked poly(glycerol sebacate) (PGS) coating was prepared in this article. MBG scaffold was prepared by a modified F127/PU co-templating process and then PGS was coated by a simple adsorption and lyophilization process. Through controlling macropore parameters and PGS coating amount, the mechanical strength, degradation rate, controlled-release and cell behavior of the composite scaffold could be modulated in a wide range. PGS coating successfully endowed MBG scaffold with improved toughness and adjustable mechanical strength covering the bearing range of trabecular bone (2-12MPa). Multilevel degradation rate of the scaffold and controlled-release rate of protein from mesopore could be achieved, with little impact on the protein activity owing to an "ultralow-solvent" coating and "nano-cavity entrapment" immobilization method. In vitro studies indicated that PGS coating promoted cell attachment and proliferation in a dose-dependent manner, without affecting the osteogenic induction capacity of MBG substrate. These results first provide strong evidence that uncrosslinked PGS might also yield extraordinary achievements in traditional MBG scaffold. With the multiparameter adjustability, the composite MBG/PGS scaffolds would have a hopeful prospect in bone tissue engineering. The design considerations and coating method of this study can also be extended to other ceramic-based artificial scaffolds and are expected to provide new thoughts on development of future tissue engineering materials.

  18. Self-complementary AAV2.5-BMP2-coated Femoral Allografts Mediated Superior Bone Healing Versus Live Autografts in Mice With Equivalent Biomechanics to Unfractured Femur

    PubMed Central

    Yazici, Cemal; Takahata, Masahiko; Reynolds, David G; Xie, Chao; Samulski, R Jude; Samulski, Jade; Beecham, E Jeffrey; Gertzman, Arthur A; Spilker, Mark; Zhang, Xinping; O'Keefe, Regis J; Awad, Hani A; Schwarz, Edward M

    2011-01-01

    Structural allografts used for critical bone defects have limited osteogenic properties for biointegration. Although ex vivo tissue-engineered constructs expressing bone morphogenetic protein-2 (BMP2) have demonstrated efficacy in critical defect models, similar success has not been achieved with off-the-shelf acellular approaches, including allografts coated with freeze-dried single-stranded adeno-associated virus (ssAAV-BMP2). To see whether the self-complementary AAV serotype 2.5 vector (scAAV2.5-BMP2) could overcome this, we performed side-by-side comparisons in vitro and in the murine femoral allograft model. Although ssAAV-BMP2 was unable to induce BMP2 expression and differentiation of C3H10T1/2 cells in culture, scAAV2.5-BMP2 transduction led to dose-dependent BMP2 expression and alkaline phosphatase activity, and displayed a 25-fold increased transduction efficiency in vivo. After 6 weeks, the ssAAV-BMP2 coating failed to demonstrate any significant effects. However, all allografts coated with 1010 scAAV2.5-BMP2 formed a new cortical shell that was indistinguishable to that formed by live autografts. Additionally, coated allografts experienced reduced resorption resulting in a threefold increase in graft bone volume versus autograft. This led to biomechanical superiority versus both allografts and autografts, and equivalent torsional rigidity to unfractured femur. Collectively, these results demonstrate that scAAV2.5-BMP2 coating overcomes the major limitations of structural allografts, which can be used to heal critical defects of any size. PMID:21206485

  19. In vitro and in vivo evaluation of bone morphogenetic protein-2 (BMP-2) immobilized collagen-coated polyetheretherketone (PEEK)

    NASA Astrophysics Data System (ADS)

    Du, Ya-Wei; Zhang, Li-Nan; Ye, Xin; Nie, He-Min; Hou, Zeng-Tao; Zeng, Teng-Hui; Yan, Guo-Ping; Shang, Peng

    2015-03-01

    Polyetheretherketone (PEEK) is regarded as one of the most potential candidates of biomaterials in spinal implant applications. However, as a bioinert material, PEEK plays a limited role in osteoconduction and osseointegration. In this study, recombinant human bone morphogenetic protein-2 (rhBMP-2) was immobilized onto the surface of collagen-coated PEEK in order to prepare a multi-functional material. After adsorbed onto the PEEK surface by hydrophobic interaction, collagen was cross-linked with N-(3-dimethylaminopropyl)-N'-ethyl carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS). EDC/NHS system also contributed to the immobilization of rhBMP-2. Water contact angle tests, XPS and SEM clearly demonstrated the surface changes. ELISA tests quantified the amount of rhBMP-2 immobilized and the release over a period of 30 d. In vitro evaluation proved that the osteogenesis differentiation rate was higher when cells were cultured on modified PEEK discs than on regular ones. In vivo tests were conducted and positive changes of major parameters were presented. This report demonstrates that the rhBMP-2 immobilized method for PEEK modification increase bioactivity in vitro and in vivo, suggesting its practicability in orthopedic and spinal clinical applications.

  20. A dual-task design of corrosion-controlling and osteo-compatible hexamethylenediaminetetrakis- (methylene phosphonic acid) (HDTMPA) coating on magnesium for biodegradable bone implants application.

    PubMed

    Zhao, Sheng; Chen, Yingqi; Liu, Bo; Chen, Meiyun; Mao, Jinlong; He, Hairuo; Zhao, Yuancong; Huang, Nan; Wan, Guojiang

    2015-05-01

    Magnesium as well as its alloys appears increasingly as a revolutionary bio-metal for biodegradable implants application but the biggest challenges exist in its too fast bio-corrosion/degradation. Both corrosion-controllable and bio-compatible Mg-based bio-metal is highly desirable in clinic. In present work, hexamethylenediaminetetrakis (methylenephosphonic acid) [HDTMPA, (H2 O3 P-CH2 )2 -N-(CH2 )6 -N-(CH2 -PO3 H2 )2 ], as a natural and bioactive organic substance, was covalently immobilized and chelating-deposited onto Mg surface by means of chemical conversion process and dip-coating method, to fullfill dual-task performance of corrosion-protective and osteo-compatible functionalities. The chemical grafting of HDTMPA molecules, by participation of functional groups on pretreated Mg surface, ensured a firmly anchored base layer, and then sub-sequential chelating reactions of HDTMPA molecules guaranteed a homogenous and dense HDTMPA coating deposition on Mg substrate. Electrochemical corrosion and immersion degradation results reveal that the HDTMPA coated Mg provides a significantly better controlled bio-corrosion/degradation behavior in phosphate buffer saline solution as compared with untreated Mg from perspective of clinic requirement. Moreover, the HDTMPA coated Mg exhibits osteo-compatible in that it induces not only bioactivity of bone-like apatite precipitation but also promotes osteoblast cells adhesion and proliferation. Our well-controlled biodegradable and biocompatible HDTMPA modified Mg might bode well for next generation bone implant application.

  1. Loss of mechanical properties in vivo and bone-implant interface strength of AZ31B magnesium alloy screws with Si-containing coating.

    PubMed

    Tan, Lili; Wang, Qiang; Lin, Xiao; Wan, Peng; Zhang, Guangdao; Zhang, Qiang; Yang, Ke

    2014-05-01

    In this study the loss of mechanical properties and the interface strength of coated AZ31B magnesium alloy (a magnesium-aluminum alloy) screws with surrounding host tissues were investigated and compared with non-coated AZ31B, degradable polymer and biostable titanium alloy screws in a rabbit animal model after 1, 4, 12 and 21weeks of implantation. The interface strength was evaluated in terms of the extraction torque required to back out the screws. The loss of mechanical properties over time was indicated by one-point bending load loss of the screws after these were extracted at different times. AZ31B samples with a silicon-containing coating had a decreased degradation rate and improved biological properties. The extraction torque of Ti6Al4V, poly-l-lactide (PLLA) and coated AZ31B increased significantly from 1week to 4weeks post-implantation, indicating a rapid osteosynthesis process over 3weeks. The extraction torque of coated AZ31B increased with implantation time, and was higher than that of PLLA after 4weeks of implantation, equalling that of Ti6Al4V at 12weeks and was higher at 21weeks. The bending loads of non-coated AZ31B and PLLA screws degraded sharply after implantation, and that of coated AZ31B degraded more slowly. The biodegradation mechanism, the coating to control the degradation rate and the bioactivity of magnesium alloys influencing the mechanical properties loss over time and bone-implant interface strength are discussed in this study and it is concluded that a suitable degradation rate will result in an improvement in the mechanical performance of magnesium alloys, making them more suitable for clinical application.

  2. Xenotransplantation and the potential risk of xenogeneic transmission of porcine viruses.

    PubMed Central

    Yoo, D; Giulivi, A

    2000-01-01

    The clinical success of allotransplantation and the shortage of donor organs have led to a proposal for the use of animal organs as alternative therapeutic materials for humans. In that regard, swine are preferable to non-human primates as a source of donor organs. While applications for clinical trials for xenotransplantation have not yet been received in Canada, several trials have already been authorized in the United States. A major concern, however, is the potential for xenogeneic transmission of viruses from animals to humans via organ, tissue, or cellular transplantation or via ex vivo exposure of humans to porcine biologic materials. Xenotransplantation allows viruses to bypass the normal immunological defense mechanisms of the recipient. Furthermore, the use of immunosuppressive drugs following transplantation may facilitate the xenogeneic transmission of zoonotic agents. Of porcine viruses, swine hepatitis E virus does not cause any clinical symptoms in the natural host but is a likely zoonotic agent that can infect humans and cause hepatitis. Porcine circovirus type 1 is prevalent in swine populations with no known association with clinical disease, while circovirus type 2 causes post-weaning multi-systemic wasting syndrome. Porcine endogenous retrovirus is integrated into the host chromosomes while porcine cytomegalovirus undergoes latent infection. Two additional porcine herpesviruses have recently been identified in swine and have been named porcine lymphotrophic herpesviruses. These herpesviruses can potentially become reactivated in human recipients after xenotransplantation. All in all, there are a number of viruses in swine that are of primary concern to screen and eliminate from xenotransplantation protocols. Epidemiology and the current knowledge on xenogeneic risk of these viruses are discussed. PMID:11041495

  3. Genetic engineering strategies to prevent the effects of antibody and complement on xenogeneic chondrocytes.

    PubMed

    Sommaggio, R; Bello-Gil, D; Pérez-Cruz, M; Brokaw, J L; Máñez, R; Costa, C

    2015-11-18

    Advances in animal transgenesis may allow using xenogeneic chondrocytes in tissue-engineering applications for clinical cartilage repair. Porcine cartilage is rejected by humoral and cellular mechanisms that could be overcome by identifying key molecules triggering rejection and developing effective genetic-engineering strategies. Accordingly, high expression of α1,2-fucosyltransferase (HT) in xenogeneic cartilage protects from galactose α1,3-galactose (Gal)-mediated antibody responses. Now, we studied whether expression of a complement inhibitor provides further protection. First, porcine articular chondrocytes (PAC) were isolated from non-transgenic, single and double transgenic pigs expressing HT and moderate levels of human CD59 (hCD59) and their response to human serum was assessed. High recombinant expression of human complement regulatory molecules hCD59 and hDAF was also attained by retroviral transduction of PAC for further analyses. Complement activation on PAC after exposure to 20 % human serum for 24 hours mainly triggered the release of pro-inflammatory cytokines IL-6 and IL-8. Transgenic expression of HT and hCD59 did not suffice to fully counteract this effect. Nevertheless, the combination of blocking anti-Gal antibodies (or C5a) and high hCD59 levels conferred very high protection. On the contrary, high hDAF expression attained the most dramatic reduction in IL-6/IL-8 secretion by a single strategy, but the additional inhibition of anti-Gal antibodies or C5a did not provide further improvement. Notably, we demonstrate that both hCD59 and hDAF inhibit anaphylatoxin release in this setting. In conclusion, our study identifies genetic-engineering approaches to prevent humoral rejection of xenogeneic chondrocytes for use in cartilage repair.

  4. [Use of xenogenic lyophilized hepatocytes in the treatment of acute and chronic liver diseases].

    PubMed

    Musselius, S G; Vasina, N V; Gladskikh, L V

    1998-01-01

    Therapeutic effect of lyophilized xenogenic hepatocytes was demonstrated on 30 dogs with acute hepatic failure and on white mice. The major biochemical values were corrected and the yeast fermentation test showed biological activity of isolated hepatocytes. Clinically, lyophilized hepatocytes were used in the treatment of patients with acute hepatic failure: orally in 47 and for extracorporeal dialysis in 8. The therapeutic effect of lyophilized hepatocytes is based on active detoxication and hemostasis correction. Clinical, laboratory, and instrumental studies showed improvement of the clinical status, decreased encephalopathy, and accelerated repair processes in the liver. Addition of lyophilized hepatocytes to combined therapy decreased the mortality by 2.5 times.

  5. Biologic effects of bacterial superantigens in a xenogeneic transplantation model for psoriasis.

    PubMed

    Boehncke, W H

    2001-12-01

    Both clinical as well as experimental data support the concept of psoriasis being a T-cell-mediated immune disease possibly triggered by bacterial superantigens. Further analysis of its pathogenesis was facilitated by the generation of a xenogeneic transplantation model in which skin from psoriatic patients is grafted onto SCID mice lacking functional B and T cells. Applying this model it was demonstrated that psoriasis can be triggered by bacterial superantigens; this process depends on the presence of immunocytes. Mutated variants of the respective superantigens exhibiting no measurable affinity to HLA class II molecules can function as competitive inhibitors in vivo.

  6. Three-phase bone scan and indium white blood cell scintigraphy following porous coated hip arthroplasty: A prospective study of the prosthetic tip

    SciTech Connect

    Oswald, S.G.; Van Nostrand, D.; Savory, C.G.; Callaghan, J.J. )

    1989-08-01

    Although few reports address the use of three-phase bone scanning (TPBS) and {sup 111}In-labeled white blood cell (In-WBC) scintigraphy in hip arthroplasty utilizing a porous coated prosthesis, the literature suggests that scintigraphic patterns in the uncomplicated patient may differ from that seen in the cemented prosthesis. In an attempt to determine the scintigraphic natural history, 25 uncomplicated porous coated hip arthroplasties in 21 patients were prospectively studied with serial TPBS and In-WBC at approximately 7 days, and at 3, 6, 12, 18, and 24 mo postoperatively. This report deals with findings related to the prosthetic tip. Only one of 136 flow studies were abnormal and only two of 136 blood-pool images demonstrated focally increased activity. All 25 prostheses (120 of 143 scans) demonstrated increased uptake on the bone phase images. The area about the tip was divided into three segments; increased uptake at 24 mo was noted in the medial, distal, and lateral segments in 16%, 72%, and 56% of prostheses, respectively. Twenty of 25 prostheses (82 of 142 scans) showed uptake on In-WBC scintigraphy, being noted in 48% of prostheses at 24 mo. We conclude that scintigraphic patterns in the uncomplicated patient with a porous coated prosthesis appear to differ from patterns described in cemented prostheses.

  7. The acetabulum: A prospective study of three-phase bone and indium white blood cell scintigraphy following porous-coated hip arthroplasty

    SciTech Connect

    Oswald, S.G.; Van Nostrand, D.; Savory, C.G.; Anderson, J.H.; Callaghan, J.J. )

    1990-03-01

    Although few studies address the use of three-phase bone scanning (TPBS) and indium-111-labeled white blood cell scintigraphy ({sup 111}In-WBC) in hip arthroplasty utilizing a porous-coated prosthesis, the literature suggests that scintigraphic patterns in the uncomplicated patient may differ from that seen with the cemented prosthesis. In an attempt to determine the scintigraphic natural history, 25 uncomplicated porous-coated hip arthroplasties in 21 patients were prospectively studied with serial TPBS and {sup 111I}n-WBC at approximately 7 days, and 3, 6, 12, 18, and 24 mo postoperatively. This report deals with findings related to the acetabulum. All 25 prostheses (144 of 144 scans) demonstrated increased uptake on the bone-phase images. Although this activity decreased with time, 76% had persistent uptake at 24 mo. Twenty-three of 25 prostheses (126 of 140 scans) showed increased uptake on {sup 111}In-WBC scintigraphy, invariably decreasing with time, but with 37% having significant uptake at 24 mo. Scintigraphic patterns in the uncomplicated porous-coated hip arthroplasty patient appear to differ from patterns described in cemented prostheses.

  8. Superior Immunologic and Therapeutic Efficacy of a Xenogeneic Genetic Cancer Vaccine Targeting Carcinoembryonic Human Antigen

    PubMed Central

    Roscilli, Giuseppe; Marra, Emanuele; Luberto, Laura; Mancini, Rita; La Monica, Nicola; Ciliberto, Gennaro

    2015-01-01

    Abstract We have generated a xenogeneic vaccine against human carcinoembryonic antigen (hCEACAM-5 or commonly hCEA) using as immunogen rhesus CEA (rhCEA). RhCEA cDNA was codon-usage optimized (rhCEAopt) and delivered by sequential DNA electro-gene-transfer (DNA-EGT) and adenoviral (Ad) vector. RhCEAopt was capable to break tolerance to CEA in hCEA transgenic mice and immune responses were detected against epitopes distributed over the entire length of the protein. Xenovaccination with rhCEA resulted in the activation of CD4+ T-cell responses in addition to self-reactive CD8+ T-cells, the development of high-titer antibodies against hCEA, and significant antitumor effects upon challenge with hCEA+ tumor cells. The superior activity of rhCEAopt compared with hCEAopt was confirmed in hCEA/HHD double-transgenic mice, where potent CD8+ T-cell responses against specific human HLA A*0201 hCEA epitopes were detected. Our data show that xenogeneic gene-based vaccination with rhCEA is a viable approach to break tolerance against CEA, thus suggesting further development in the clinical setting. PMID:25869226

  9. Superior Immunologic and Therapeutic Efficacy of a Xenogeneic Genetic Cancer Vaccine Targeting Carcinoembryonic Human Antigen.

    PubMed

    Aurisicchio, Luigi; Roscilli, Giuseppe; Marra, Emanuele; Luberto, Laura; Mancini, Rita; La Monica, Nicola; Ciliberto, Gennaro

    2015-06-01

    We have generated a xenogeneic vaccine against human carcinoembryonic antigen (hCEACAM-5 or commonly hCEA) using as immunogen rhesus CEA (rhCEA). RhCEA cDNA was codon-usage optimized (rhCEAopt) and delivered by sequential DNA electro-gene-transfer (DNA-EGT) and adenoviral (Ad) vector. RhCEAopt was capable to break tolerance to CEA in hCEA transgenic mice and immune responses were detected against epitopes distributed over the entire length of the protein. Xenovaccination with rhCEA resulted in the activation of CD4+ T-cell responses in addition to self-reactive CD8+ T-cells, the development of high-titer antibodies against hCEA, and significant antitumor effects upon challenge with hCEA+ tumor cells. The superior activity of rhCEAopt compared with hCEAopt was confirmed in hCEA/HHD double-transgenic mice, where potent CD8+ T-cell responses against specific human HLA A*0201 hCEA epitopes were detected. Our data show that xenogeneic gene-based vaccination with rhCEA is a viable approach to break tolerance against CEA, thus suggesting further development in the clinical setting.

  10. Oral immunization with xenogeneic antibodies stimulates the production of systemic and mucosal anti-idiotypic antibodies.

    PubMed Central

    Collins, A M; Roberton, D M; Hosking, C S; Flannery, G R

    1991-01-01

    The humoral and mucosal immune responses to oral immunization with xenogeneic antibodies were studied using an animal model in which female rabbits were fed daily doses of the MOPC-315 murine IgA antibody, and were mated during the course of the feeding programme. Serum and colostrum samples were assayed for the presence of anti-idiotypic antibodies by ELISA assay, before and after depletion of anti-IgA antibodies, by affinity chromatography using another murine IgA idiotype. It was shown that all animals responded to exposure to the MOPC-315 idiotype with the production of serum anti-murine immunoglobulin antibodies and that four of six animals produced serum anti-idiotypic antibodies. That the immune response included antibodies directed against the antigen-binding site was confirmed by competition ELISA assay. Mucosal IgG and IgA anti-immunoglobulin antibodies were present in milk from all antibody-fed rabbits tested, and IgA anti-idiotypic antibodies were detectable in the colostrum of one rabbit. The results provide some support for the hypothesis that human exposure to xenogeneic antibodies, most commonly bovine milk immunoglobulins, may provoke the production of anti-idiotypic antibodies, and that such exposure may lead to disturbances of immune regulation. PMID:1916890

  11. Genetic modification of alphaGal expression in xenogeneic endothelial cells yields a complex immunological response.

    PubMed

    Fischbeck, J A; Baier, J M; Akella, R; Hern-Anderson, D; Schmidt, C E

    2001-12-01

    The source of cells for tissue engineering applications remains a hurdle, predominantly for procedures in which there is insufficient time to harvest a patient's own cells. Animal cells are readily available, but undergo immune rejection. Rejection of animal (i.e., xenogeneic) tissue involves practically every component of the immune system. The initial phase, hyperacute rejection (HAR), involves natural xenoreactive antibodies and the complement system, and leads to endothelial cell lysis and rapid tissue destruction. The cell-surface epitope, galactose-alpha(1,3)-galactose (alphaGal), is presumed to play a key role in HAR. The later stage of immune response (delayed xenograft rejection or DXR), is mediated by immune cells such as monocytes. Carbohydrates are likely also involved in DXR, but their role in this phase of the immune response is less clear. A better understanding of all stages of xenogeneic immune rejection may make it feasible to create cell lines that are immune tolerant. In these studies, we have genetically modified bovine endothelial cells to study the roles of carbohydrates in immune rejection. Our studies suggest that one or more epitopes other than alphaGal may influence complement-mediated lysis. Furthermore, antibodies, as instigators in the complement response, and monocytes appear to recognize different cell surface epitopes.

  12. [Xenogeneic cell therapeutics: Treatment of type 1 diabetes using porcine pancreatic islets and islet cells].

    PubMed

    Godehardt, Antonia W; Schilling-Leiß, Dagmar; Sanzenbacher, Ralf; Tönjes, Ralf R

    2015-11-01

    In view of the existing shortage of human donor organs and tissues, xenogeneic cell therapeutics (xCT) offer an alternative for adequate treatment. In particular, porcine pancreatic islets and islet cells have already entered the field of experimental therapy for type-1 diabetes mellitus (T1DM) patients. Thereby, xCT depict challenging products with a glance on medical, ethical, and regulatory questions. With cross-species transplantation (xenotransplantation), the risk of immunological graft rejection as well as the risk of infectious transmission of microbial and viral pathogens must be considered. This includes the bidirectional transmission of microorganisms from graft to host as well as from host to graft. Crossing the border of species requires a critical risk-benefit evaluation as well as a thorough longtime surveillance of transplant recipients after treatment. The international legal and regulatory requirements for xCT are inter alia based on the World Health Organization criteria summarized in the Changsha Communiqué (2008). In the European Union, they were reflected by the European Medicines Agency (EMA) Guideline on Xenogeneic Cell-based Medicinal Products following the implementation of the Regulation on Advanced Therapies (ATMP). On the basis of this regulation, the first non-clinical and clinical experiences were obtained for porcine islets. The results suggest that supportive treatment of T1DM risk patients with xCT may be an alternative to established allogeneic organ transplantation in the future.

  13. Processed xenogenic cartilage as innovative biomatrix for cartilage tissue engineering: effects on chondrocyte differentiation and function.

    PubMed

    Schwarz, Silke; Elsaesser, Alexander F; Koerber, Ludwig; Goldberg-Bockhorn, Eva; Seitz, Andreas M; Bermueller, Christian; Dürselen, Lutz; Ignatius, Anita; Breiter, Roman; Rotter, Nicole

    2015-12-01

    One key point in the development of new bioimplant matrices for the reconstruction and replacement of cartilage defects is to provide an adequate microenvironment to ensure chondrocyte migration and de novo synthesis of cartilage-specific extracellular matrix (ECM). A recently developed decellularization and sterilization process maintains the three-dimensional (3D) collagen structure of native septal cartilage while increasing matrix porosity, which is considered to be crucial for cartilage tissue engineering. Human primary nasal septal chondrocytes were amplified in monolayer culture and 3D-cultured on processed porcine nasal septal cartilage scaffolds. The influence of chondrogenic growth factors on neosynthesis of ECM proteins was examined at the protein and gene expression levels. Seeding experiments demonstrated that processed xenogenic cartilage matrices provide excellent environmental properties for human nasal septal chondrocytes with respect to cell adhesion, migration into the matrix and neosynthesis of cartilage-specific ECM proteins, such as collagen type II and aggrecan. Matrix biomechanical stability indicated that the constructs retrieve full stability and function during 3D culture for up to 42 days, proportional to collagen type II and GAG production. Thus, processed xenogenic cartilage offers a suitable environment for human nasal chondrocytes and has promising potential for cartilage tissue engineering in the head and neck region.

  14. Comparative study of the efficacy of decellularization treatment of allogenic and xenogeneic nerves as nerve conduits.

    PubMed

    Wang, Wei; Itoh, Soichiro; Takakuda, Kazuo

    2016-02-01

    The objective of this study was to compare the results of allogenic and xenogeneic nerve grafts that were treated using decellularization. The sciatic nerves of Sprague-Dawley rats and the median nerves of Japanese white rabbits were decellularized with sodium dodecyl sulfate and Triton X-100 and examined with a scanning electron microscope and immunofluorescence staining. A bridge-graft into the sciatic nerve in Wistar rats was performed with the decellularized nerves (10 mm in length for short-term evaluation; 15 mm in length for long-term evaluation). As a control, an isograft was performed. The specimens were harvested at 4 weeks postoperatively and prepared for immunohistochemistry. Function, electrophysiological and histomorphological analyses were performed to evaluate nerve recovery at 24 weeks postoperatively. The 3-dimensional structure of the basal lamina column, on which the cell adhesion molecules were integrated, was preserved through the decellularization protocols. Limited ED1-positive macrophage invasion was observed, and abundant NF 160-positive axons, which were accompanied by S-100-positive Schwann cells, penetrated through the implanted nerves. The sciatic nerve function and electrophysiological and histomorphological analyses suggest that the xenogeneic nerve graft was statistically indistinguishable from the allogenic nerve graft but slightly inferior to the isograft in supporting the axonal regeneration and functional recovery.

  15. Characterizing the Mechanistic Pathways of the Instant Blood-Mediated Inflammatory Reaction in Xenogeneic Neonatal Islet Cell Transplantation

    PubMed Central

    Liuwantara, David; Chew, Yi Vee; Favaloro, Emmanuel J.; Hawkes, Joanne M.; Burns, Heather L.; O'Connell, Philip J.; Hawthorne, Wayne J.

    2016-01-01

    Introduction The instant blood-mediated inflammatory reaction (IBMIR) causes major loss of islets after transplantation and consequently represents the initial barrier to survival of porcine neonatal islet cell clusters (NICC) after xenotransplantation. Methods This study used novel assays designed to characterize the various immunologic components responsible for xenogeneic IBMIR to identify initiators and investigate processes of IBMIR-associated coagulation, complement activation and neutrophil infiltration. The IBMIR was induced in vitro by exposing NICC to platelet-poor or platelet-rich human plasma or isolated neutrophils. Results We found that xenogeneic IBMIR was characterized by rapid, platelet-independent thrombin generation, with addition of platelets both accelerating and exacerbating this response. Platelet-independent complement activation was observed as early as 30 minutes after NICC exposure to plasma. However, membrane attack complex formation was not observed in NICC histopathology sections until after 60 minutes. We demonstrated for the first time that NICC-mediated complement activation was necessary for neutrophil activation in the xenogeneic IBMIR setting. Finally, using the Seahorse extracellular flux analyzer, we identified substantial loss of islet function (up to 40%) after IBMIR with surviving NICC showing evidence of mitochondrial damage. Conclusions This study used novel assays to describe multiple key pathways by which xenogeneic IBMIR causes islet destruction, allowing further refinement of future interventions aimed at resolving the issue of IBMIR in xenotransplantation. PMID:27500267

  16. The effect of surface treatment on the surface texture and contact angle of electrochemically deposited hydroxyapatite coating and on its interaction with bone-forming cells.

    PubMed

    Eliaz, Noam; Shmueli, Sharon; Shur, Irena; Benayahu, Dafna; Aronov, Daniel; Rosenman, Gil

    2009-10-01

    This work demonstrates the effects of both surface preparation and surface post-treatment by exposure to electron beam on the surface texture, contact angle and the interaction with bone-forming cells of electrochemically deposited hydroxyapatite (HAp) coating. Both the surface texture and the contact angle of the ground titanium substrate changed as a result of either heat treatment following soaking in NaOH solution or soaking in H(2)O(2) solution. Consequently, the shape of the current transients during potentiostatic deposition of HAp changed, and the resulting coatings exhibited different surface textures and contact angles. The developed interfacial area ratio Sdr and the core fluid retention index Sci were found more reliable than the mean roughness R(a) and the root-mean-square roughness Z(rms) in correlating the adhesion of the coating to the metal substrate and the cellular response with surface texture. The NaOH pretreatment provided the highest surface area and induced the highest cell attachment, even though the H(2)O(2) treatment provided the highest hydrophilicity to the metal substrate. Electrodeposition at pH 6 was found preferable compared to electrodeposition at pH 4.2. The ability to modify the cellular response by exposure to unique electron-beam surface treatment was demonstrated. The very high hydrophilicity of the as-deposited HAp coating enhanced its bioactivity.

  17. Biological Evaluation (In Vitro and In Vivo) of Bilayered Collagenous Coated (Nano Electrospun and Solid Wall) Chitosan Membrane for Periodontal Guided Bone Regeneration.

    PubMed

    Lotfi, Ghogha; Shokrgozar, Mohammad Ali; Mofid, Rasoul; Abbas, Fatemeh Mashhadi; Ghanavati, Farzin; Baghban, Alireza Akbarzadeh; Yavari, Seyedeh Kimia; Pajoumshariati, Seyedramin

    2016-07-01

    The application of barrier membranes in guided bone regeneration (GBR) has become a commonly used surgical technique in periodontal research. The objectives of this study were to evaluate the in vitro biocompatibility and osteogenic differentiation of mesenchymal stem cells (MSCs) on two different collagenous coatings (nano electrospun fibrous vs. solid wall) of bilayered collagen/chitosan membrane and their histological evaluation on bone regeneration in rabbit calvarial defects. It was found that chitosan-nano electrospun collagen (CNC) membranes had higher proliferation/metabolic activity compared to the chitosan-collagen (CC) and pristine chitosan membranes. The qRT-PCR analysis demonstrated the CNC membranes induced significant expression of osteogenic genes (Osteocalcin, RUNX2 and Col-α1) in MSCs. Moreover, higher calcium content and alkaline phosphatase activity of MSCs were observed compared to the other groups. Histologic and histomorphometric evaluations were performed on the uncovered (negative control) as well as covered calvarial defects of ten adult white rabbits with different membranes (CNC, CC, BioGide (BG, positive control)) at 1 and 2 months after surgery. More bone formation was detected in the defects covered with CNC and BG membranes than those covered by CC and the negative control. No inflammation and residual biomaterial particles were observed on the membrane surface or in the surrounding tissues in the surgical areas. These results suggest that bilayer CNC membrane can have the potential for use as a GBR membrane material facilitating bone formation.

  18. Long-term Bone Remodeling in HA-coated Stems: A Radiographic Review of 208 Total Hip Arthroplasties (THAs) with 15 to 20 Years Follow-up.

    PubMed

    Boldt, Jens G; Cartillier, Jean-Claude; Machenaud, Alain; Vidalain, Jean-Pierre

    2015-11-01

    We present a prospective study focused on radiographic long-term outcomes and bone remodeling at a mean of 17.0 years (range: 15 to 20) in 208 cementless fully HA-coated femoral stems (Corail, DePuy International Ltd, Leeds, UK). Total hip replacements in this study were performed by three members of the surgeon design group between 1986 and 1991. Radiographic evaluation focused on periprosthetic osteolysis, bone remodeling, osseous integration, subsidence, metaphyseal or diaphyseal load transfer, and femoral stress shielding. The radiographs were digitized and examined with contrast-enhancing software for analysis of the trabecular architecture. Radiographic signs of aseptic stem loosening were visible in two cases (1%). Three stems (1.4%) showed metaphyseal periprosthetic osteolysis in four of seven Gruen zones associated with eccentric polyethylene wear awaiting metaphyseal bone grafting and cup liner exchange. One stem (0.5%) was revised due to infection. No stem altered in varus or valgus alignment more than two degrees, and mean subsidence was 0.1 mm (range: 0 to 2 mm) after a mean of 17.0 years. A total of 5 stems (2.4%) required or are awaiting revision surgery. Trabecular orientation and micro-anatomy suggested main proximal load-transfer patterns in all except 3 cases (98.6%). Combined metaphyseal and diaphyseal osseointegration and bone remodeling were visible in 100 stems (48%). Diaphyseal stress shielding and cortical thickening were observed in 3 stems (1.4%). Other radiographic features are discussed in depth. This long-term study of 208 fully HA-coated Corail stems showed satisfactory osseointegration and fixation in 203 cases (97.6%) after a mean of 17.0 years follow-up. Stem failures were associated with extreme eccentric polyethylene wear.

  19. Are xenogeneic anti-tissue transglutaminase antibodies the holy grail for celiac patients?

    PubMed

    Ivanovski, Petar Ilija; Ivanovski, Ivan P; Sedlarevic, Rade

    2007-01-01

    Celiac disease is an immune mediated disorder, the only one with a well-established origin, resulting from a permanent gluten intolerance. Although a gluten-free diet is currently the "safe" and appropriate therapy for celiac disease, this is not always an easy and simple option as "harmful" gluten may contaminate food during the processing and preparation phases. There are also further social pressures, which might be more pressing for young celiac patients, in following a strict gluten-free diet. Therefore, a new therapeutic approaches are sought which would permit celiacs to "peacefully" coexist with gluten. Presently, the most promising looks search for genetically modified wheat lacking toxic gluten peptides and the use of oral endopeptidases in attempt to curb gluten toxicity. Recently discovered role of anti-tissue transglutaminase antibodies in celiac pathogenesis has brought a prospect for a new hypothetical therapeutic approach, an oral immunization of celiacs with xenogeneic anti-tissue transglutaminase antibodies.

  20. Success rates and immunologic responses of autogenic, allogenic, and xenogenic treatments to repair articular cartilage defects.

    PubMed

    Revell, Christopher M; Athanasiou, Kyriacos A

    2009-03-01

    This review examines current approaches available for articular cartilage repair, not only in terms of their regeneration potential, but also as a function of immunologic response. Autogenic repair techniques, including osteochondral plug transplantation, chondrocyte implantation, and microfracture, are the most widely accepted clinical treatment options due to the lack of immunogenic reactions, but only moderate graft success rates have been reported. Although suspended allogenic chondrocytes are shown to evoke an immune response upon implantation, allogenic osteochondral plugs and tissue-engineered grafts using allogenic chondrocytes exhibit a tolerable immunogenic response. Additionally, these repair techniques produce neotissue with success rates approaching those of currently available autogenic repair techniques, while simultaneously obviating their major hindrance of donor tissue scarcity. To date, limited research has been performed with xenogenic tissue, although several studies demonstrate the potential for its long-term success. This article focuses on the various treatment options for cartilage repair and their associated success rates and immunologic responses.

  1. Xenogenic transfer of isolated murine mitochondria into human rho0 cells can improve respiratory function.

    PubMed

    Katrangi, Eyad; D'Souza, Gerard; Boddapati, Sarathi V; Kulawiec, Mariola; Singh, Keshav K; Bigger, Brian; Weissig, Volkmar

    2007-12-01

    Mitochondrial DNA mutations are the direct cause of several physiological disorders and are also associated with the aging process. The modest progress made over the past two decades towards manipulating the mitochondrial genome and understanding its function within living mammalian cells means that cures for mitochondrial DNA mutations are still elusive. Here, we report that transformed mammalian cells internalize exogenous isolated mitochondria upon simple co-incubation. We first demonstrate the physical presence of internalized mitochondria within recipient cells using fluorescence microscopy. Second, we show that xenogenic transfer of murine mitochondria into human cells lacking functional mitochondria can functionally restore respiration in cells lacking mtDNA. Third, utilizing the natural competence of isolated mitochondria to take up linear DNA molecules, we demonstrate the feasibility of using cellular internalization of isolated exogenous mitochondria as a potential tool for studying mitochondrial genetics in living mammalian cells.

  2. Success Rates and Immunologic Responses of Autogenic, Allogenic, and Xenogenic Treatments to Repair Articular Cartilage Defects

    PubMed Central

    Revell, Christopher M.

    2009-01-01

    This review examines current approaches available for articular cartilage repair, not only in terms of their regeneration potential, but also as a function of immunologic response. Autogenic repair techniques, including osteochondral plug transplantation, chondrocyte implantation, and microfracture, are the most widely accepted clinical treatment options due to the lack of immunogenic reactions, but only moderate graft success rates have been reported. Although suspended allogenic chondrocytes are shown to evoke an immune response upon implantation, allogenic osteochondral plugs and tissue-engineered grafts using allogenic chondrocytes exhibit a tolerable immunogenic response. Additionally, these repair techniques produce neotissue with success rates approaching those of currently available autogenic repair techniques, while simultaneously obviating their major hindrance of donor tissue scarcity. To date, limited research has been performed with xenogenic tissue, although several studies demonstrate the potential for its long-term success. This article focuses on the various treatment options for cartilage repair and their associated success rates and immunologic responses. PMID:19063664

  3. The protective effects of prostaglandin E1 on sinusoidal endothelial cells in xenogeneic pig liver perfusion.

    PubMed

    Yagi, T; Ikai, I; Terajima, H; Satoh, S; Kanazawa, A; Shinohara, H; Uesugi, T; Yoneyama, T; Gomi, T; Takahashi, R; Yamamoto, M; Inamoto, T; Yamaoka, Y

    1997-11-01

    The effects of prostaglandin E1 (PGE1) on hepatic sinusoidal endothelial cells (SEC) in the xenogeneic immunoreaction were investigated. Porcine livers were perfused with fresh human blood via the portal vein (PV) and the hepatic artery (HA) either with the administration of PGE1 (Group PG) or without PGE1 (Group C). The creatine kinase-BB component (CK-BB) in the perfusate was measured to assess SEC damage. SEC activation and complement activation were evaluated immunohistochemically by the expression of von Willebrand factor (vWF) and by the deposition of membrane attack complex (MAC), respectively. Xenoperfusion in Group C was discontinued between 4 and 6 hr due to the rapid elevation of HA pressures and the massive loss of perfusate. In Group PG, both PV and HA pressures were kept stable for up to 9 hr. In Group C, severe interlobular bleeding and diffuse extrasinusoidal hemorrhage were observed at 4 hr histologically, while in Group PG, the hepatic architecture was maintained without hemorrhage at 6 hr. MAC was markedly deposited on SEC and parenchymal cells at 3 hr in both groups. The amount of vWF, however, was expressed on SEC in large amounts at 1 hr in Group C, while small amounts were expressed at 1 hr in Group PG. In Group PG, CK-BB release was significantly lower than in Group C (P < 0.01). These results suggest that PGE1 suppressed SEC activation and protected the impairment of hepatic SEC during xenoperfusion without suppressing complement activation, resulting in the prolongation of xenogeneic liver perfusion.

  4. Decellularized Extracellular Matrix Derived from Porcine Adipose Tissue as a Xenogeneic Biomaterial for Tissue Engineering

    PubMed Central

    Choi, Young Chan; Choi, Ji Suk; Kim, Beob Soo; Kim, Jae Dong; Yoon, Hwa In

    2012-01-01

    Cells in tissues are surrounded by the extracellular matrix (ECM), a gel-like material of proteins and polysaccharides that are synthesized and secreted by cells. Here we propose that the ECM can be isolated from porcine adipose tissue and holds great promise as a xenogeneic biomaterial for tissue engineering and regenerative medicine. Porcine adipose tissue is easily obtained in large quantities from commonly discarded food waste. Decellularization protocols have been developed for extracting an intact ECM while effectively eliminating xenogeneic epitopes and minimally disrupting the ECM composition. Porcine adipose tissue was defatted by homogenization and centrifugation. It was then decellularized via chemical (1.5 M sodium chloride and 0.5% sodium dodecyl sulfate) and enzymatic treatments (DNase and RNase) with temperature control. After decellularization, immunogenic components such as nucleic acids and α-Gal were significantly reduced. However, abundant ECM components, such as collagen (332.9±12.1 μg/mg ECM dry weight), sulfated glycosaminoglycan (GAG, 85±0.7 μg/mg ECM dry weight), and elastin (152.6±4.5 μg/mg ECM dry weight), were well preserved in the decellularized material. The biochemical and mechanical features of a decellularized ECM supported the adhesion and growth of human cells in vitro. Moreover, the decellularized ECM exhibited biocompatibility, long-term stability, and bioinductivity in vivo. The overall results suggest that the decellularized ECM derived from porcine adipose tissue could be useful as an alternative biomaterial for xenograft tissue engineering. PMID:22559904

  5. Inkjet printing of Chitlac-nanosilver--a method to create functional coatings for non-metallic bone implants.

    PubMed

    Nganga, Sara; Moritz, Niko; Kolakovic, Ruzica; Jakobsson, Kristina; Nyman, Johan O; Borgogna, Massimiliano; Travan, Andrea; Crosera, Matteo; Donati, Ivan; Vallittu, Pekka K; Sandler, Niklas

    2014-10-22

    Biostable fiber-reinforced composites, based on bisphenol-A-dimethacrylate and triethyleneglycoldimethacrylate thermoset polymer matrix reinforced with E-glass fibers have been successfully used in cranial reconstructions and the material has been approved for clinical use. As a further refinement of these implants, antimicrobial, non-cytotoxic coatings on the composites were created by an immersion procedure driven by strong electrostatic interactions. Silver nanoparticles (nAg) were immobilized in lactose-modified chitosan (Chitlac) to prepare the bacteriostatic coatings. Herein, we report the use of inkjet technology (a drop-on-demand inkjet printer) to deposit functional Chitlac-nAg coatings on the thermoset substrates. Characterization methods included scanning electron microscopy, scanning white light interferometry and electro-thermal atomic absorption spectroscopy. Inkjet printing enabled the fast and flexible functionalization of the thermoset surfaces with controlled coating patterns. The coatings were not impaired by the printing process: the kinetics of silver release from the coatings created by inkjet printing and conventional immersion technique was similar. Further research is foreseen to optimize printing parameters and to tailor the characteristics of the coatings for specific clinical applications.

  6. Enhanced Ex Vivo Expansion of Human Hematopoietic Progenitors on Native and Spin Coated Acellular Matrices Prepared from Bone Marrow Stromal Cells

    PubMed Central

    Wasnik, Samiksha; Kantipudi, Suma; Kirkland, Mark A.; Pande, Gopal

    2016-01-01

    The extracellular microenvironment in bone marrow (BM) is known to regulate the growth and differentiation of hematopoietic stem and progenitor cells (HSPC). We have developed cell-free matrices from a BM stromal cell line (HS-5), which can be used as substrates either in native form or as tissue engineered coatings, for the enhanced ex vivo expansion of umbilical cord blood (UCB) derived HSPC. The physicochemical properties (surface roughness, thickness, and uniformity) of native and spin coated acellular matrices (ACM) were studied using scanning and atomic force microscopy (SEM and AFM). Lineage-specific expansion of HSPC, grown on these substrates, was evaluated by immunophenotypic (flow cytometry) and functional (colony forming) assays. Our results show that the most efficient expansion of lineage-specific HSPC occurred on spin coated ACM. Our method provides an improved protocol for ex vivo HSPC expansion and it offers a system to study the in vivo roles of specific molecules in the hematopoietic niche that influence HSPC expansion. PMID:26981135

  7. A new uncemented hydroxyapatite-coated femoral component for the treatment of femoral neck fractures: two-year radiostereometric and bone densitometric evaluation in 50 hips.

    PubMed

    Sköldenberg, O G; Salemyr, M O; Bodén, H S; Lundberg, A; Ahl, T E; Adolphson, P Y

    2011-05-01

    Our aim in this pilot study was to evaluate the fixation of, the bone remodelling around, and the clinical outcome after surgery of a new, uncemented, fully hydroxyapatite-coated, collared and tapered femoral component, designed specifically for elderly patients with a fracture of the femoral neck. We enrolled 50 patients, of at least 70 years of age, with an acute displaced fracture of the femoral neck in this prospective single-series study. They received a total hip replacement using the new component and were followed up regularly for two years. Fixation was evaluated by radiostereometric analysis and bone remodelling by dual-energy x-ray absorptiometry. Hip function and the health-related quality of life were assessed using the Harris hip score and the EuroQol-5D. Up to six weeks post-operatively there was a mean subsidence of 0.2 mm (-2.1 to +0.5) and a retroversion of a mean of 1.2° (-8.2° to +1.5°). No component migrated after three months. The patients had a continuous loss of peri-prosthetic bone which amounted to a mean of 16% (-49% to +10%) at two years. The mean Harris hip score was 82 (51 to 100) after two years. The two-year results from this pilot study indicate that this new, uncemented femoral component can be used for elderly patients with osteoporotic fractures of the femoral neck.

  8. Promotion of osteogenic differentiation of stem cells and increase of bone-bonding ability in vivo using urease-treated titanium coated with calcium phosphate and gelatin

    NASA Astrophysics Data System (ADS)

    Huang, Zhong-Ming; Qi, Yi-Ying; Du, Shao-Hua; Feng, Gang; Unuma, Hidero; Yan, Wei-Qi

    2013-10-01

    Because of its excellent biocompatibility and low allergenicity, titanium has been widely used for bone replacement and tissue engineering. To produce a desirable composite with enhanced bone response and mechanical strength, in this study bioactive calcium phosphate (CaP) and gelatin composites were coated onto titanium (Ti) via a novel urease technique. The cellular responses to the CaP/gelatin/Ti (CaP/gel/Ti) and bone bonding ability were evaluated with proliferation and osteogenic differentiation of mesenchymal stem cells (MSCs) on CaP/gel/Ti and CaP/Ti in vitro. The results showed that the optical density values, alkaline phosphatase expression and genes expression of MSCs on CaP/gel/Ti were similar to those on CaP/Ti, yet significantly higher than those on pure Ti (p < 0.05). CaP/gel/Ti and CaP/Ti rods (2 mm in diameter, 10 mm in length) were also implanted into femoral shaft of rabbits and pure Ti rods served as control (n = 10). Histological examination, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) measurements were performed at 4 and 8 weeks after the operation. The histological and SEM observations demonstrated clearly that more new bone formed on the surface of CaP/gel/Ti than in the other two groups at each time point. The CaP/gel/Ti bonded to the surrounding bone directly with no intervening soft tissue layer. An interfacial layer, containing Ti, Ca and P, was found to form at the interface between bone and the implant on all three groups by EDS analysis. However, the content of Ca, P in the surface of CaP/gel/Ti implants was more than in the other two groups at each time point. The CaP/gel/Ti modified by the urease method was not only beneficial for MSCs proliferation and osteogenic differentiation, but also favorable for bone bonding ability on Ti implants in vivo, suggesting that Ti functionalized with CaP and gelatin might have a great potential in clinical joint replacement or dental implants.

  9. Effective immobilization of BMP-2 mediated by polydopamine coating on biodegradable nanofibers for enhanced in vivo bone formation.

    PubMed

    Cho, Hyeong-jin; Perikamana, Sajeesh Kumar Madhurakkat; Lee, Ji-hye; Lee, Jinkyu; Lee, Kyung-Mi; Shin, Choongsoo S; Shin, Heungsoo

    2014-07-23

    Although bone morphogenic proteins (BMPs) have been widely used for bone regeneration, the ideal delivery system with optimized dose and minimized side effects is still active area of research. In this study, we developed bone morphogenetic protein-2(BMP-2) immobilized poly(l-lactide) (PLLA) nanofibers inspired by polydopamine, which could be ultimately used as membranes for guided bone regeneration, and investigated their effect on guidance of in vitro cell behavior and in vivo bone formation. Surface chemical analysis of the nanofibers confirmed successful immobilization of BMP-2 mediated by polydopamine, and about 90% of BMP-2 was stably retained on the nanofiber surface for at least 28 days. The alkaline phosphatase activity and calcium mineralization of human mesenchymal stem cells (hMSCs) after 14 days of in vitro culture was significantly enhanced on nanofibers immobilized with BMP-2. More importantly, BMP-2 at a relatively small dose was highly active following implantation to the critical-sized defect in the cranium of mice; radiographic analysis demonstrated that 77.8 ± 11.7% of newly formed bone was filled within the defect for a BMP-2-immobilized groups at the concentration of 124 ± 9 ng/cm(2), as compared to 5.9 ± 1.0 and 34.1 ± 5.5% recovery, for a defect-only and a polydopamine-only group, respectively. Scanning and transmission electron microscopy of samples from the BMP-2 immobilized group showed fibroblasts and osteoblasts with nanofiber strands in the middle of regenerated bone tissue, revealing the importance of interaction between implanted nanofibers and the neighboring extracellular environment. Taken together, our data support that the presentation of BMP-2 on the surface of nanofibers as immobilized by utilizing polydopamine chemistry may be an effective method to direct bone growth at relatively low local concentration.

  10. Comparative Efficacies of Long-Term Serial Transplantation of Syngeneic, Allogeneic, Xenogeneic, or CTLA4Ig-Overproducing Xenogeneic Adipose Tissue-Derived Mesenchymal Stem Cells on Murine Systemic Lupus Erythematosus.

    PubMed

    Choi, Eun Wha; Lee, Hee Woo; Shin, Il Seob; Park, Ji Hyun; Yun, Tae Won; Youn, Hwa Young; Kim, Sung-Joo

    2016-01-01

    Allogeneic and xenogeneic transplantation are suitable alternatives for treating patients with stem cell defects and autoimmune diseases. The purpose of this study was to compare the effects of long-term serial transplantation of adipose tissue-derived mesenchymal stem cells (ASCs) from (NZB × NZW) F1 mice (syngeneic), BALB/c mice (allogeneic), or humans (xenogeneic) on systemic lupus erythematosus (SLE). The effects of transplanting human ASCs overproducing CTLA4Ig (CTLA4Ig-hASC) were also compared. Animals were divided into five experimental groups, according to the transplanted cell type. Approximately 500,000 ASCs were administered intravenously every 2 weeks from 6 to 60 weeks of age to all mice except for the control mice, which received saline. The human ASC groups (hASC and CTLA4Ig-hASC) showed a 13-week increase in average life spans and increased survival rates and decreased blood urea nitrogen, proteinuria, and glomerular IgG deposition. The allogeneic group also showed higher survival rates compared to those of the control, up to 40, 41, 42, 43, 44, 45, 52, and 53 weeks of age. Syngeneic ASC transplantation did not accelerate the mortality of the mice. The mean life span of both the syngeneic and allogeneic groups was prolonged for 6-7 weeks. Both human ASC groups displayed increased serum interleukin-10 and interleukin-4 levels, whereas both mouse ASC groups displayed significantly increased GM-CSF and interferon-γ levels in the serum. The strongest humoral immune response was induced by xenogeneic transplantation, followed by allogeneic, CTLA4Ig-xenogeneic, and syngeneic transplantations. Long-term serial transplantation of the ASCs from various sources displayed different patterns of cytokine expression and humoral responses, but all of them increased life spans in an SLE mouse model.

  11. Evaluation of osteoinduction properties of the demineralized bovine foetal growth plate powder as a new xenogenic biomaterial in rat.

    PubMed

    Bigham, A S; Shadkhast, M; Bigham Sadegh, A; Shafiei, Z; Lakzian, A; Khalegi, M R

    2011-10-01

    The aim of this study was evaluation of osteoinductive properties of demineralized bovine foetal growth plate in submuscular transplantation (ectopic osteoinduction) as a new xenogenic biomaterial in rat model. Demineralized bovine foetal growth plate was ectopically implanted in 18 male Sprague-Dawley rats. In 18 of the animals under aseptic conditions two submuscular pouches were created between external and internal oblique abdominal muscles in the two flanks: the right was left empty (sham) and the left was filled with 20mg of demineralized bovine foetal growth plate powder. Radiographs were taken in 2, 4 and 6 weeks after the surgery, then six animals were pharmacologically euthanized after 2, 4 and 6 weeks for histopathological evaluation. Results showed: (1) osteoinductivity of xenogenic demineralized bovine foetal growth plate powder, and (2) earlier mineralization of ectopically implanted demineralized bovine foetal growth plate in the submuscular implanted area. Our results show that submuscular implantation of xenogenic demineralized bovine foetal growth plate has osteoinductive properties in a rat model.

  12. Tooth-derived bone graft material

    PubMed Central

    Kim, Young-Kyun; Lee, Junho; Kim, Kyung-Wook; Murata, Masaru; Akazawa, Toshiyuki; Mitsugi, Masaharu

    2013-01-01

    With successful extraction of growth factors and bone morphogenic proteins (BMPs) from mammalian teeth, many researchers have supported development of a bone substitute using tooth-derived substances. Some studies have also expanded the potential use of teeth as a carrier for growth factors and stem cells. A broad overview of the published findings with regard to tooth-derived regenerative tissue engineering technique is outlined. Considering more than 100 published papers, our team has developed the protocols and techniques for processing of bone graft material using extracted teeth. Based on current studies and studies that will be needed in the future, we can anticipate development of scaffolds, homogenous and xenogenous tooth bone grafts, and dental restorative materials using extracted teeth. PMID:24471027

  13. In vivo depletion of lymphotoxin-alpha expressing lymphocytes inhibits xenogeneic graft-versus-host-disease.

    PubMed

    Chiang, Eugene Y; Kolumam, Ganesh; McCutcheon, Krista M; Young, Judy; Lin, Zhonghua; Balazs, Mercedesz; Grogan, Jane L

    2012-01-01

    Graft-versus-host disease (GVHD) is a major barrier to successful allogeneic hematopoietic cell transplantation and is largely mediated by activated donor lymphocytes. Lymphotoxin (LT)-α is expressed by subsets of activated T and B cells, and studies in preclinical models demonstrated that targeted depletion of these cells with a mouse anti-LT-α monoclonal antibody (mAb) was efficacious in inhibiting inflammation and autoimmune disease. Here we demonstrate that LT-α is also upregulated on activated human donor lymphocytes in a xenogeneic model of GVHD and targeted depletion of these donor cells ameliorated GVHD. A depleting humanized anti-LT-α mAb, designated MLTA3698A, was generated that specifically binds to LT-α in both the soluble and membrane-bound forms, and elicits antibody-dependent cellular cytotoxicity (ADCC) activity in vitro. Using a human peripheral blood mononuclear cell transplanted SCID (Hu-SCID) mouse model of GVHD, the anti-human LT-α mAb specifically depleted activated LT-expressing human donor T and B cells, resulting in prolonged survival of the mice. A mutation in the Fc region, rendering the mAb incapable of mediating ADCC, abolished all in vitro and in vivo effects. These data support a role for using a depleting anti-LT-α antibody in treating immune diseases such as GVHD and autoimmune diseases.

  14. Transferring Xenogenic Mitochondria Provides Neural Protection Against Ischemic Stress in Ischemic Rat Brains.

    PubMed

    Huang, Po-Jui; Kuo, Chi-Chung; Lee, Hsiu-Chin; Shen, Ching-I; Cheng, Fu-Chou; Wu, Shih-Fang; Chang, Jui-Chih; Pan, Hung-Chuan; Lin, Shinn-Zong; Liu, Chin-San; Su, Hong-Lin

    2016-01-01

    Transferring exogenous mitochondria has therapeutic effects on damaged heart, liver, and lung tissues. Whether this protective effect requires the symbiosis of exogenous mitochondria in host cells remains unknown. Here xenogenic mitochondria derived from a hamster cell line were applied to ischemic rat brains and rat primary cortical neurons. Isolated hamster mitochondria, either through local intracerebral or systemic intra-arterial injection, significantly restored the motor performance of brain-ischemic rats. The brain infarct area and neuronal cell death were both attenuated by the exogenous mitochondria. Although internalized mitochondria could be observed in neurons and astrocytes, the low efficacy of mitochondrial internalization could not completely account for the high rate of rescue of the treated neural cells. We further illustrated that disrupting electron transport or ATPase synthase in mitochondria significantly attenuated the protective effect, suggesting that intact respiratory activity is essential for the mitochondrial potency on neural protection. These results emphasize that nonsymbiotic extracellular mitochondria can provide an effective cell defense against acute injurious ischemic stress in the central nervous system.

  15. Peripheral target reinnervation following orthotopic grafting of fetal allogeneic and xenogeneic dorsal root ganglia.

    PubMed

    Rosario, C M; Dubovy, P; Sidman, R L; Aldskogius, H

    1995-04-01

    The sensory reinnervation of dermal papillae and epidermis of glabrous skin, interosseal Pacinian corpuscles, and muscle spindles of the soleus and extensor digitorum longus muscles has been examined 1, 3, and 8 months (allografts) or 3 and 5 weeks (xenografts) following orthotopic grafting of fetal allogeneic or xenogeneic (mouse) dorsal root ganglia (DRG) into ganglionectomized adult rats. Sensory axons in target tissues were identified immunohistochemically by monoclonal antibodies against growth-associated peptide (GAP-43), heavy neurofilament protein (RT-97), anti-mouse-specific membrane glycoprotein Thy-1.2, and polyclonal antibody to calcitonin gene-related peptide (CGRP). Absence of axonal marker staining in target structures of control animals 10 days or 3 months following ipsilateral enucleation of the L3-L6 DRG without grafting indicated an elimination of host normal (intact), regenerating, or collaterally sprouting nerve fibers. The consistent finding of immunolabeled axons ending free and in encapsulated structures in the target tissues of both allo- and xenografted rats indicates that grafted primary sensory neurons can survive and send axonal processes down the full length of the hind limb, to terminate in host target tissues. Axons of xenografted fetal mouse sensory neurons grow in adult rat hosts for distances of 4 cm or more, attaining lengths far greater than called for by their normal developmental programs.

  16. Comparison of Clinical Efficacy Between Modular Cementless Stem Prostheses and Coated Cementless Long-Stem Prostheses on Bone Defect in Hip Revision Arthroplasty

    PubMed Central

    Li, Huibin; Chen, Fang; Wang, Zhe; Chen, Qian

    2016-01-01

    Background The aim of this study was to investigate and compare the clinical efficacy of modular cementless stem and coated cementless long-stem prostheses in hip revision arthroplasty. Material/Methods Sixty-five patients with complete hip revision surgery data during January 2005 to March 2015 were selected from the People’s Hospital of Linyi City and randomly divided into a S-ROM group (implanted with cementless modular stem prostheses, n=32) and a SLR-PLUS group (implanted with cementless coated long-stem prostheses, n=33). Harris score was used to evaluate the hip function of the patients in order to measure the clinical efficacy of the prostheses in total hip arthroplasty. Anteroposterior pelvic radiographs and lateral pelvic radiographs were taken and each patient’s hip arthroplasty condition was recorded. Kaplan-Meier method was applied to compare the cumulative 5-year non-revision rate between the 2 prostheses and log-rank method was used to inspect the statistical data. Results The Harris scores of both the S-ROM group and the SLR-PLUS group were significantly higher at 12 months after the operation than those before the operation (both P<0.05). The Harris scores of the patients with type I/II bone defects in the S-ROM group were not significantly different from those of the same types in the SLR-PLUS group at all time points (all P>0.05), while the Harris scores of the patients with type IIIA/IIIB in the S-ROM group were both significantly higher than those of the same types in the SLR-PLUS group at 3 months, 6 months, and 12 months after the operation (all P<0.05). No significant difference was found in the cumulative 5-year non-revision rate between the type I/II patients in the S-ROM group (92.31%) and the patients of the same types in the SLR-PLUS group (85.71%) (P>0.05). However, the cumulative 5-year non-revision rate of the type IIIA/IIIB patients in the S-ROM group (89.47%) was significantly different from the patients of the same types in

  17. Poly(dopamine) coating of 3D printed poly(lactic acid) scaffolds for bone tissue engineering.

    PubMed

    Kao, Chia-Tze; Lin, Chi-Chang; Chen, Yi-Wen; Yeh, Chia-Hung; Fang, Hsin-Yuan; Shie, Ming-You

    2015-11-01

    3D printing is a versatile technique to generate large quantities of a wide variety of shapes and sizes of polymer. The aim of this study is to develop functionalized 3D printed poly(lactic acid) (PLA) scaffolds and use a mussel-inspired surface coating to regulate cell adhesion, proliferation and differentiation of human adipose-derived stem cells (hADSCs). We prepared PLA 3D scaffolds coated with polydopamine (PDA). The chemical composition and surface properties of PDA/PLA were characterized by XPS. PDA/PLA modulated hADSCs' responses in several ways. Firstly, adhesion and proliferation, and cell cycle of hADSCs cultured on PDA/PLA were significantly enhanced relative to those on PLA. In addition, the collagen I secreted from cells was increased and promoted cell attachment and cell cycle progression were depended on the PDA content. In osteogenesis assay, the ALP activity and osteocalcin of hADSCs cultured on PDA/PLA were significantly higher than seen in those cultured on pure PLA scaffolds. Moreover, hADSCs cultured on PDA/PLA showed up-regulation of the ang-1 and vWF proteins associated with angiogenic differentiation. Our results demonstrate that the bio-inspired coating synthetic PLA polymer can be used as a simple technique to render the surfaces of synthetic scaffolds active, thus enabling them to direct the specific responses of hADSCs.

  18. Silencing porcine CMAH and GGTA1 genes significantly reduces xenogeneic consumption of human platelets by porcine livers

    PubMed Central

    Butler, James R.; Paris, Leela L.; Blankenship, Ross L.; Sidner, Richard A.; Martens, Gregory R.; Ladowski, Joeseph M.; Li, Ping; Estrada, Jose L; Tector, Matthew; Tector, A. Joseph

    2015-01-01

    Background A profound thrombocytopenia limits hepatic xenotransplantation in the pig-to-primate model. Porcine livers also have shown the ability to phagocytose human platelets in the absence of immune-mediate injury. Recently, inactivation of the porcine ASGR1 gene has been shown to decrease this phenomenon. Inactivating GGTA1 and CMAH genes has reduced the antibody-mediated barrier to xenotransplantation; herein we describe the effect that these modifications have on xenogeneic consumption of human platelets in the absence of immune-mediated graft injury. Methods WT, ASGR1−/−, GGTA1−/−, and GGTA1−/−CMAH−/− knockout pigs were compared for their xenogeneic hepatic consumption of human platelets. An in vitro assay was established to measure the association of human platelets with liver sinusoidal endothelial cells (LSECs) by immunohistochemistry. Perfusion models were used to measure human platelet uptake in livers from WT, ASGR1−/−, GGTA1−/−, and GGTA1−/− CMAH−/− pigs. Results GGTA1−/−, CMAH−/− LSECs exhibited reduced levels of human platelet binding in vitro, when compared to GGTA1−/− and WT LSECs. In a continuous perfusion model, GGTA1−/− CMAH−/− livers consumed fewer human platelets than GGTA1−/− and WT livers. GGTA1−/− CMAH−/− livers also consumed fewer human platelets than ASGR1−/− livers in a single pass model. Conclusions Silencing the porcine carbohydrate genes necessary to avoid antibody-mediated rejection in a pig-to-human model also reduces the xenogeneic consumption of human platelets by the porcine liver. The combination of these genetic modifications may be an effective strategy to limit the thrombocytopenia associated with pig-to-human hepatic xenotransplantation. PMID:26906939

  19. Xenogeneic therapeutic cancer vaccines as breakers of immune tolerance for clinical application: to use or not to use?

    PubMed

    Strioga, Marius M; Darinskas, Adas; Pasukoniene, Vita; Mlynska, Agata; Ostapenko, Valerijus; Schijns, Virgil

    2014-07-07

    Accumulation of firm evidence that clinically apparent cancer develops only when malignant cells manage to escape immunosurveillance led to the introduction of tumor immunotherapy strategies aiming to reprogramm the cancer-dysbalanced antitumor immunity and restore its capacity to control tumor growth. There are several immunotherapeutical strategies, among which specific active immunotherapy or therapeutic cancer vaccination is one of the most promising. It targets dendritic cells (DCs) which have a unique ability of inducing naive and central memory T cell-mediated immune response in the most efficient manner. DCs can be therapeutically targeted either in vivo/in situ or by ex vivo manipulations followed by their re-injection back into the same patient. The majority of current DC targeting strategies are based on autologous or allogeneic tumor-associated antigens (TAAs) which possess various degrees of inherent tolerogenic potential. Therefore still limited efficacy of various tumor immunotherapy approaches may be attributed, among various other mechanisms, to the insufficient immunogenicity of self-protein-derived TAAs. Based on such an idea, the use of homologous xenogeneic antigens, derived from different species was suggested to overcome the natural immune tolerance to self TAAs. Xenoantigens are supposed to differ sufficiently from self antigens to a degree that renders them immunogenic, but at the same time preserves an optimal homology range with self proteins still allowing xenoantigens to induce cross-reactive T cells. Here we discuss the concept of xenogeneic vaccination, describe the cons and pros of autologous/allogeneic versus xenogeneic therapeutic cancer vaccines, present the results of various pre-clinical and several clinical studies and highlight the future perspectives of integrating xenovaccination into rapidly developing tumor immunotherapy regimens.

  20. Assessment of bone healing in rabbit calvaria grafted with three different biomaterials.

    PubMed

    Takauti, Carlos Alberto Yoshihiro; Futema, Fabio; Brito Junior, Rui Barbosa de; Abrahão, Aline Corrêa; Costa, Claudio; Queiroz, Celso Silva

    2014-01-01

    This study evaluated the bone regeneration process in rabbit calvaria induced by three types of biomaterials: two xenogenous, consisting of deproteinized bovine bone, while the other was alloplastic, based on biphasic calcium phosphate. Five New Zealand white rabbits weighing between 2,900 and 3,500 g were submitted to four standard 8 mm-diameter perforations at the parietal bone. Three perforations were filled with three grafts and biomaterials, two of them received bovine Bio-Oss® and Endobon® Xenograft Granules, and the other consisted of fully alloplastic Straumann® Bone Ceramic. The fourth remaining cavity was used as control with coagulum. After eight weeks, the animals were sacrificed, and the samples were prepared for morphometric and qualitative analysis. The cavities filled with alloplastic biomaterials showed higher percentages of newly formed bone (p<0.05), while the cavities with xenogenous biomaterials showed higher amount of residual graft (p<0.05). Although the results showed greater bone formation with Straumann® Bone Ceramic, further studies are required to prove which is the more effective biomaterial for bone induction process.

  1. Biocompatible cephalosporin-hydroxyapatite-poly(lactic-co-glycolic acid)-coatings fabricated by MAPLE technique for the prevention of bone implant associated infections

    NASA Astrophysics Data System (ADS)

    Rădulescu, Dragoş; Grumezescu, Valentina; Andronescu, Ecaterina; Holban, Alina Maria; Grumezescu, Alexandru Mihai; Socol, Gabriel; Oprea, Alexandra Elena; Rădulescu, Marius; Surdu, Adrian; Trusca, Roxana; Rădulescu, Radu; Chifiriuc, Mariana Carmen; Stan, Miruna S.; Constanda, Sabrina; Dinischiotu, Anca

    2016-06-01

    In this study we aimed to obtain functionalized thin films based on hydroxyapatite/poly(lactic-co-glycolic acid) (HAp/PLGA) containing ceftriaxone/cefuroxime antibiotics (ATBs) deposited by Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique. The prepared thin films were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-Ray diffraction (XRD), selected area electron diffraction (SAED), and infra red (IR) analysis. HAp/PLGA/ATBs thin films sustained the growth of human osteoblasts, proving their good biocompatibility. The microscopic evaluation and the culture-based quantitative assay of the E. coli biofilm development showed that the thin films inhibited the initial step of microbial attachment as well as the subsequent colonization and biofilm development on the respective surfaces. This study demonstrates that MAPLE technique could represent an appealing technique for the fabrication of antibiotics-containing polymeric implant coatings. The bioevaluation results recommend this type of surfaces for the prevention of bone implant microbial contamination and for the enhanced stimulation of the implant osseointegration process.

  2. Production of Human Endothelial Cells Free from Soluble Xenogeneic Antigens for Bioartificial Small Diameter Vascular Graft Endothelization

    PubMed Central

    de Carvalho, Juliana Lott; Zonari, Alessandra; de Paula, Ana Cláudia Chagas; Martins, Thaís Maria da Mata; Gomes, Dawidson Assis; Goes, Alfredo Miranda

    2015-01-01

    Arterial bypass graft implantation remains the primary therapy for patients with advanced cardiovascular disease, but most lack adequate saphenous vein or other conduits for bypass procedures and would benefit from a bioartificial conduit. This study aimed to produce human endothelial cells (hECs) in large scale, free from xenogeneic antigens, to develop a small diameter, compatible vessel for potential use as a vascular graft. Human adipose-derived stromal cells (hASCs) were isolated, cultured, and differentiated in the presence of human serum and used for the reendothelization of a decellularized rat aorta. hASC derived ECs (hASC-ECs) expressed VEGFR2, vWf and CD31 endothelial cell markers, the latter in higher levels than hASCs and HUVECs, and were shown to be functional. Decellularization protocol yielded aortas devoid of cell nuclei, with preserved structure, including a preserved basement membrane. When seeded with hASC-ECs, the decellularized aorta was completely reendothelized, and the hASC-ECs maintained their phenotype in this new condition. hASCs can be differentiated into functional hECs without the use of animal supplements and are capable of reendothelizing a decellularized rat aorta while maintaining their phenotype. The preservation of the basement membrane following decellularization supported the complete reendothelization of the scaffold with no cell migration towards other layers. This approach is potentially useful for rapid obtention of compatible, xenogeneic-free conduit. PMID:26146626

  3. Bone graft

    MedlinePlus

    Autograft - bone; Allograft - bone; Fracture - bone graft; Surgery - bone graft; Autologous bone graft ... Fuse joints to prevent movement Repair broken bones (fractures) that have bone loss Repair injured bone that ...

  4. A silver carp skin derived collagen in bone defect treatment-A histological study in a rat model.

    PubMed

    Hadzik, Jakub; Kubasiewicz-Ross, Paweł; Kunert-Keil, Christiane; Jurczyszyn, Kamil; Nawrot-Hadzik, Izabela; Dominiak, Marzena; Gedrange, Tomasz

    2016-11-01

    In recent years, there has been increasing interest in elaboration of novel therapeutic strategies, such as the use of the marine collagen products. Biochemical properties of marine collagen are different from those of mammalian collagen; e.g., its extremely high solubility in diluted acid. Extracts produced using low temperature techniques contain a number of small proteins and collagen with preserved triple helix structure. The aim of the study was to evaluate the influence of a new marine product Collgel(®) obtained with a unique method from a silver carp (Hypophthalmichthys molitrix) on bone defect healing in a rat study. For this purpose bone defects with diameters of 5mm were created in 15 animals and subsequently filled with Collgel combined with another commercially available material. Samples were processed for histological evaluation and a Micro-CT study was performed. Histological analysis showed new bone formation in all groups after 8 weeks. The bone formation was significantly increased in treated bone lesions compared to untreated bone tissue. However no significant difference was noted between the healing of the defects filled with xenogenic bovine derived bone substitute alone and xenogenic, bovine derived bone substitute combined with a marine delivered collagen. Finding from the histological examination was confirmed in a Micro-CT study. The study has shown that the new marine product can be used instead of conventional porcine or bovine collagen membranes in guided bone regeneration.

  5. Low-magnitude, high-frequency vibration promotes the adhesion and the osteogenic differentiation of bone marrow-derived mesenchymal stem cells cultured on a hydroxyapatite-coated surface: The direct role of Wnt/β-catenin signaling pathway activation.

    PubMed

    Chen, Bailing; Lin, Tao; Yang, Xiaoxi; Li, Yiqiang; Xie, Denghui; Zheng, Wenhui; Cui, Haowen; Deng, Weimin; Tan, Xin

    2016-11-01

    The positive effect of low-magnitude, high‑frequency (LMHF) vibration on implant osseointegration has been demonstrated; however, the underlying cellular and molecular mechanisms remain unknown. The aim of this study was to explore the effect of LMHF vibration on the adhesion and the osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) cultured on hydroxyapatite (HA)-coated surfaces in an in vitro model as well as to elucidate the molecular mechanism responsible for the effects of LMHF vibration on osteogenesis. LMHF vibration resulted in the increased expression of fibronectin, which was measured by immunostaining and RT-qPCR. Stimulation of BMSCs by LMHF vibration resulted in the rearrangement of the actin cytoskeleton with more prominent F-actin. Moreover, the expression of β1 integrin, vinculin and paxillin was notably increased following LMHF stimulation. Scanning electron microscope observations revealed that there were higher cell numbers and more extracellular matrix attached to the HA-coated surface in the LMHF group. Alkaline phosphatase activity as well as the expression of osteogenic-specific genes, namely Runx2, osterix, collagen I and osteocalcin, were significantly elevated in the LMHF group. In addition, the protein expression of Wnt10B, β-catenin, Runx2 and osterix was increased following exposure to LMHF vibration. Taken together, the findings of this study indicate that LMHF vibration promotes the adhesion and the osteogenic differentiation of BMSCs on HA-coated surfaces in vitro, and LMHF vibration may directly induce osteogenesis by activating the Wnt/β‑catenin signaling pathway. These data suggest that LMHF vibration enhances the osseointegration of bone to a HA-coated implant, and provide a scientific foundation for improving bone-implant osseointegration through the application of LMHF vibration.

  6. In vitro osteoinduction of demineralized bone.

    PubMed

    Torricelli, P; Fini, M; Giavaresi, G; Giardino, R

    1998-05-01

    Among numerous available materials for osseous repair and reconstruction, those presenting osteoinductive characteristics and promoting bone regeneration are preferable. Fresh autologous bone is one of the most effective, but it has some disadvantages and risks. Demineralized bone matrix (DBM) is considered to be a valid alternative, because it seems to show osteogenic potential, ascribed to the presence of bone morphogenetic proteins. In addition it can be prepared without difficulty and preserved without losing osteoinductive properties. The aim of the study was to evaluate the osteoinductive ability of xenogenic DBM, by testing DBM powder obtained from rabbit long bones, in cell culture of murine fibroblasts, alone or associated with electromagnetic field (EMF), that are known to exhibit biologic effects on cells: in particular they are used in orthopedics to improve bone formation. At the end of experiment, alkaline phosphatase (ALP) activity, calcium levels and cell proliferation and morphology were evaluated. A statistically significant stimulation of ALP activity and cell proliferation and a morphological change of fibroblasts were found. The results obtained show how DBM and EMF have different effects on cells, and that together they have synergic action toward bone induction.

  7. Bone tumor

    MedlinePlus

    Tumor - bone; Bone cancer; Primary bone tumor; Secondary bone tumor; Bone tumor - benign ... The cause of bone tumors is unknown. They often occur in areas of the bone that grow rapidly. Possible causes include: Genetic defects ...

  8. Results of a phase I/II clinical trial: standardized, non-xenogenic, cultivated limbal stem cell transplantation

    PubMed Central

    2014-01-01

    Background To determine if a standardized, non-xenogenic, reduced manipulation cultivation and surgical transplantation of limbal stem cell grafts is a safe and effective treatment option for patients with total and partial limbal stem cell deficiency. Methods In vitro cellular outgrowth and phenotype of the limbal epithelial cell and composite grafts were validated using a new protocol. Patients received either autologous (n = 15) or allogenic (n = 3) explants cultured using a standardized protocol free from xenogenic products. The resulting grafts were transplanted using a reduced manipulation surgical technique. Results The majority of cells (>50%) displayed a progenitor phenotype typified by positive immunofluorescence for ∆Np63, CK14 and ABCG2 and low immunofluorescence for CK3/12 and desmoglein 3 proteins. The surgical protocol was designed to minimize manipulation and the graft itself was secured without sutures. The transplant recipients were followed for a mean of 24 months. Twelve of the 18 transplant recipients were graded as anatomically successful (67%), based on the defined success parameters. There was a significant reduction in corneal neovascularization, which was accompanied by an improvement in pain though not photophobia or central corneal opacity post transplant. The transplantation protocol showed no measureable effect on visual acuity. Conclusion We conclude that this standardized culture system and surgical approach is safe and effective in reducing corneal neovascularization. The technique is free from animal contaminants and maintains a large proportion of progenitor cells. Although this technique did not improve visual function, restoring a functional epithelial cell layer and reducing corneal neovascularization provides an improved platform for a penetrating keratoplasty to ultimately improve visual function. PMID:24589151

  9. Induction of multinucleated giant cells in response to small sized bovine bone substitute (Bio-Oss™) results in an enhanced early implantation bed vascularization

    PubMed Central

    Barbeck, M.; Udeabor, S. E.; Lorenz, J.; Kubesch, A.; Choukroun, J.; Sader, R. A.; Kirkpatrick, C. J.; Ghanaati, S.

    2014-01-01

    Purpose: The host tissue reaction to the xenogeneic bone substitute Bio-Oss™ (Geistlich Biomaterials, Wolhousen, Switzerland) was investigated focusing on the participating inflammatory cells and implantation bed vascularization. Materials and Methods: Bio-Oss™ was implanted subcutaneously into CD1 mice for up to 60 days and analyzed by means of specialized histological and histomorphometrical techniques after explantation. Results: Bio-Oss™ induced within the first 15 days an early high vascularization combined with a marked presence of multinucleated giant cells. The latter cells were associated mainly with the smaller sized granules within the implantation bed. Toward the end of the study the number of multinucleated giant cells decreased while the tissue reaction to the larger granules was mainly mononuclear. Conclusion: The results of the present study showed that smaller xenogeneic bone substitute granules induce multinucleated giant cells, whereas the larger-sized ones became integrated within the implantation bed by means of a mononuclear cell-triggered granulation tissue. Obviously, the presence of multinucleated giant cells within biomaterial implantation beds is not only related to the type of synthetic bone substitute material, but also to the granule size of the natural-based xenogeneic bone substitute material. PMID:25593863

  10. Genipin crosslinking reduced the immunogenicity of xenogeneic decellularized porcine whole-liver matrices through regulation of immune cell proliferation and polarization

    PubMed Central

    Wang, Yujia; Bao, Ji; Wu, Xiujuan; Wu, Qiong; Li, Yi; Zhou, Yongjie; Li, Li; Bu, Hong

    2016-01-01

    Decellularized xenogeneic whole-liver matrices are plausible biomedical materials for the bioengineering of liver transplantation. A common method to reduce the inflammatory potential of xenogeneic matrices is crosslinking. Nevertheless, a comprehensive analysis of the immunogenic features of cross-linked decellularized tissue is still lacking. We aimed to reduce the immunogenicity of decellularized porcine whole-liver matrix through crosslinking with glutaraldehyde or genipin, a new natural agent, and investigated the mechanism of the immune-mediated responses. The histologic assessment of the host’s immune reaction activated in response to these scaffolds, as well as the M1/M2 phenotypic polarization profile of macrophages, was studied in vivo. The genipin-fixed scaffold elicited a predominantly M2 phenotype response, while the glutaraldehyde-fixed scaffold resulted in disrupted host tissue remodeling and a mixed macrophage polarization profile. The specific subsets of immune cells involved in the responses to the scaffolds were identified in vitro. Crosslinking alleviated the host response by reducing the proliferation of lymphocytes and their subsets, accompanied by a decreased release of both Th1 and Th2 cytokines. Therefore, we conclude that the natural genipin crosslinking could lower the immunogenic potential of xenogeneic decellularized whole-liver scaffolds. PMID:27098308

  11. Genipin crosslinking reduced the immunogenicity of xenogeneic decellularized porcine whole-liver matrices through regulation of immune cell proliferation and polarization

    NASA Astrophysics Data System (ADS)

    Wang, Yujia; Bao, Ji; Wu, Xiujuan; Wu, Qiong; Li, Yi; Zhou, Yongjie; Li, Li; Bu, Hong

    2016-04-01

    Decellularized xenogeneic whole-liver matrices are plausible biomedical materials for the bioengineering of liver transplantation. A common method to reduce the inflammatory potential of xenogeneic matrices is crosslinking. Nevertheless, a comprehensive analysis of the immunogenic features of cross-linked decellularized tissue is still lacking. We aimed to reduce the immunogenicity of decellularized porcine whole-liver matrix through crosslinking with glutaraldehyde or genipin, a new natural agent, and investigated the mechanism of the immune-mediated responses. The histologic assessment of the host’s immune reaction activated in response to these scaffolds, as well as the M1/M2 phenotypic polarization profile of macrophages, was studied in vivo. The genipin-fixed scaffold elicited a predominantly M2 phenotype response, while the glutaraldehyde-fixed scaffold resulted in disrupted host tissue remodeling and a mixed macrophage polarization profile. The specific subsets of immune cells involved in the responses to the scaffolds were identified in vitro. Crosslinking alleviated the host response by reducing the proliferation of lymphocytes and their subsets, accompanied by a decreased release of both Th1 and Th2 cytokines. Therefore, we conclude that the natural genipin crosslinking could lower the immunogenic potential of xenogeneic decellularized whole-liver scaffolds.

  12. A Xenogeneic-Free Protocol for Isolation and Expansion of Human Adipose Stem Cells for Clinical Uses

    PubMed Central

    Escobedo-Lucea, Carmen; Bellver, Carmen; Gandia, Carolina; Sanz-Garcia, Andres; Esteban, Francisco J.; Mirabet, Vicente; Forte, Giancarlo; Moreno, Isabel; Lezameta, Melissa; Ayuso-Sacido, Angel; Garcia-Verdugo, José M.

    2013-01-01

    Human adipose stem cells (hASCs) play a crucial role in the fields of regenerative medicine and tissue engineering for different reasons: the abundance of adipose tissue, their easy harvesting, the ability to multipotent differentiation and the fact that they do not trigger allogeneic blood response or secrete cytokines that act as immunosuppressants. The vast majority of protocols use animal origin reagents, with the underlying risk of transmitting infections by non-human pathogens. We have designed a protocol to isolate and maintain the properties of hASCs avoiding xenogeneic reagents. These changes not only preserve hASCs morphology, but also increase cell proliferation and maintain their stem cell marker profile. On the other hand, human serum albumin (HSA), Tryple® and human Serum (HS), do not affect hASCs multipotent differentiation ability. The amendments introduced do not trigger modifications in the transcriptional profile of hASCs, alterations in key biochemical pathways or malignization. Thus, we have proven that it is possible to isolate and maintain hASCs avoiding animal reagents and, at the same time, preserving crucial culture parameters during long term culture. Thereby we have revealed a novel and effective tool for the improvement of clinical, cell-based therapies. PMID:23874459

  13. Effects of xenogeneic, allogeneic and isogeneic thymus grafts on lymphocyte populations in peripheral lymphoid organs of the nude rat.

    PubMed

    Hougen, H P; Klausen, B; Stenvang, J P; Kraemmer, J; Rygaard, J

    1987-04-01

    In order to gain information about the effect of xenografted, allografted and isografted thymic tissue on peripheral lymphoid organs of immune-deficient rats, athymic nude LEW rats of ninth backcross-intercross were grafted with fetal calf and neonatal BDIX and LEW thymus. Adrenalectomy was also performed in some animals in order to obtain a possible enhancement of the immunological reconstitution. Both groups of isogeneic-thymus-grafted animals had more T helper cells than the nude controls. Furthermore, they had more densely populated paracortical areas in the inguinal lymph nodes and higher lymphocyte counts in the thoracic duct lymph. Finally, the inguinal lymph nodes contained germinal centres. Xenogeneic and allogeneic thymus transplants did not induce constant changes in the parameters observed compared with the untreated nudes. No clear difference was observed between the adrenalectomized and non-adrenalectomized thymic-isografted animals. We therefore conclude that of all the experimental animals examined the isografted nude rats show by far the best response and that adrenalectomy seems unnecessary for the success of neonatal isogeneic thymus grafts. We also conclude that the isogeneic-thymus-grafted nude rat is a suitable tool for immunological reconstitution studies.

  14. Successful xenogeneic germ cell transplantation from Jundia catfish (Rhamdia quelen) into adult Nile tilapia (Oreochromis niloticus) testes.

    PubMed

    Silva, M A; Costa, G M J; Lacerda, S M S N; Brandão-Dias, P F P; Kalapothakis, E; Silva Júnior, A F; Alvarenga, E R; França, L R

    2016-05-01

    Fish germ cell transplantation presents several important potential applications for aquaculture, including the preservation of germplasm from endangered fish species with high genetic and commercial values. Using this technique in studies developed in our laboratory with adult male Nile tilapias (Oreochromis niloticus), all the necessary procedures were successfully established, allowing the production of functional sperm and healthy progeny approximately 2months after allogeneic transplantation. In the present study, we evaluated the viability of the adult Nile tilapia testis to generate sperm after xenogeneic transplant of germ cells from sexually mature Jundia catfish (Rhamdia quelen) that belong to a different taxonomic order. Therefore, in order to investigate at different time-periods post-transplantation, the presence and development of donor PKH26 labeled catfish germ cells were followed in the tilapia seminiferous tubules. From 7 to 20days post-transplantation, only PKH26 labeled spermatogonia were observed, whereas spermatocytes at different stages of development were found at 70days. Germ cell transplantation success and progression of spermatogenesis were indicated by the presence of labeled PKH26 spermatids and sperm on days 90 and 120 post-transplantation, respectively. Confirming the presence of the catfish genetic material in the tilapia testis, all recipient tilapias evaluated (n=8) showed the genetic markers evaluated. Therefore, we demonstrated for the first time that the adult Nile tilapia testis offers the functional conditions for development of spermatogenesis with sperm production from a fish species belonging to a different order, which provides an important new venue for aquaculture advancement.

  15. Xenogenic (porcine) acellular dermal matrix promotes growth of granulation tissues in the wound healing of Fournier gangrene.

    PubMed

    Zhang, Zhaoxin; Lv, Lei; Mamat, Masut; Chen, Zhao; Zhou, Zhitao; Liu, Lihua; Wang, Zhizhong

    2015-01-01

    This article investigates the application values of Xenogenic (porcine) acellular dermal matrix (XADM) in preparation of a Fournier gangrene wound bed. Thirty-six consecutive cases of patients with Fournier gangrene between 2002 and 2012 were enrolled in our department of our hospital. The patients were divided into two groups according to different methods of wound bed preparation after surgical débridement, including the experimental group (17 cases) and the control group (19 cases). The wounds in the experimental group were covered with XADM after surgical wound débridement, whereas the wounds were cleaned with hydrogen peroxide and sodium hypochlorite solution (one time/day) in the control group. The wound bed preparation time and hospital stay were then compared in the two groups. The wound preparation time was 13.64 ± 1.46 days and hospitalization period was 26.06 ± 0.83 days in the experimental XADM group. In the control group, the wound bed preparation time and hospitalization period were 22.37 ± 1.38 and 38.11 ± 5.60 days, respectively. The results showed statistical differences between these two groups. When used in wound débridement after Fournier gangrene, XADM protects interecological organizations, promotes the growth of granulation tissues, and maximally retains function and morphology of the perineum and penis.

  16. Bone Biopsy

    MedlinePlus

    ... Physician Resources Professions Site Index A-Z Bone Biopsy Bone biopsy uses a needle and imaging guidance ... limitations of Bone Biopsy? What is a Bone Biopsy? A bone biopsy is an image-guided procedure ...

  17. Sandcastle Worm-Inspired Blood-Resistant Bone Graft Binder Using a Sticky Mussel Protein for Augmented In Vivo Bone Regeneration.

    PubMed

    Kim, Hyo Jeong; Choi, Bong-Hyuk; Jun, Sang Ho; Cha, Hyung Joon

    2016-12-01

    Xenogenic bone substitutes are commonly used during orthopedic reconstructive procedures to assist bone regeneration. However, huge amounts of blood accompanied with massive bone loss usually increase the difficulty of placing the xenograft into the bony defect. Additionally, the lack of an organic matrix leads to a decrease in the mechanical strength of the bone-grafted site. For effective bone grafting, this study aims at developing a mussel adhesion-employed bone graft binder with great blood-resistance and enhanced mechanical properties. The distinguishing water (or blood) resistance of the binder originates from sandcastle worm-inspired complex coacervation using negatively charged hyaluronic acid (HA) and a positively charged recombinant mussel adhesive protein (rMAP) containing tyrosine residues. The rMAP/HA coacervate stabilizes the agglomerated bone graft in the presence of blood. Moreover, the rMAP/HA composite binder enhances the mechanical and hemostatic properties of the bone graft agglomerate. These outstanding features improve the osteoconductivity of the agglomerate and subsequently promote in vivo bone regeneration. Thus, the blood-resistant coacervated mussel protein glue is a promising binding material for effective bone grafting and can be successfully expanded to general bone tissue engineering.

  18. Analysis of retrieved hydroxyapatite-coated hip prostheses

    NASA Astrophysics Data System (ADS)

    Gross, K. A.; Walsh, W.; Swarts, E.

    2004-06-01

    Hydroxyapatite (HAp) coatings are used extensively on orthopaedic devices to improve the adhesion of bone to the prosthesis. This approach increases the integrity and longevity of the implanted prosthesis. Four HAp-coated hip components recovered from patients during revision surgery were investigated for bone attachment and coating modification after storage in ethanol or formaldehyde. Orthopedic components displayed preferable bone attachment on microtextured areas and little bone on smoother areas. The coating microstructure differed between three coatings that remained on the prosthesis surface, ranging from completely crystalline coatings made by vacuum plasma spraying to less crystalline coatings manufactured by air plasma spraying. Coating failure for the lower crystallinity coatings was observed by a crack at the interface that was possibly caused by the dissolution of an amorphous phase. While higher crystallinity coatings degraded by coating delamination, the lower crystallinity coating produced loose particulate on the outer coating surface. Coating morphology as observed by scanning electron microscopy (SEM) displayed lamellae fracture, chemical dissolution, osteoclastic resorption, and precipitation in agreement with previously identified in-vitro events. The coating longevity appeared to be extended in those areas subject to lower levels of stress and more bone coverage.

  19. Rapamycin generates anti-apoptotic human Th1/Tc1 cells via autophagy for induction of xenogeneic GVHD.

    PubMed

    Amarnath, Shoba; Flomerfelt, Francis A; Costanzo, Carliann M; Foley, Jason E; Mariotti, Jacopo; Konecki, Daniel M; Gangopadhyay, Anu; Eckhaus, Michael; Wong, Susan; Levine, Bruce L; June, Carl H; Fowler, Daniel H

    2010-05-01

    Murine T cells exposed to rapamycin maintain flexibility towards Th1/Tc1 differentiation, thereby indicating that rapamycin promotion of regulatory T cells (Tregs) is conditional. The degree to which rapamycin might inhibit human Th1/Tc1 differentiation has not been evaluated. In the presence of rapamycin, T cell costimulation and polarization with IL-12 or IFN-α permitted human CD4+ and CD8+ T cell differentiation towards a Th1/Tc1 phenotype; activation of STAT1 and STAT4 pathways essential for Th1/Tc1 polarity was preserved during mTOR blockade but instead abrogated by PI3 kinase inhibition. Such rapamycin-resistant human Th1/Tc1 cells: (1) were generated through autophagy (increased LC3BII expression; phenotype reversion by autophagy inhibition via 3-MA or siRNA for Beclin1); (2) expressed anti-apoptotic bcl-2 family members (reduced Bax, Bak; increased phospho-Bad); (3) maintained mitochondrial membrane potentials; and (4) displayed reduced apoptosis. In vivo, type I polarized and rapamycin-resistant human T cells caused increased xenogeneic graft-versus-host disease (x-GVHD). Murine recipients of rapamycin-resistant human Th1/Tc1 cells had: (1) persistent T cell engraftment; (2) increased T cell cytokine and cytolytic effector function; and (3) T cell infiltration of skin, gut, and liver. Rapamycin therefore does not impair human T cell capacity for type I differentiation. Rather, rapamycin yields an anti-apoptotic Th1/Tc1 effector phenotype by promoting autophagy.

  20. Fractal texture analysis of the healing process after bone loss.

    PubMed

    Borowska, Marta; Szarmach, Janusz; Oczeretko, Edward

    2015-12-01

    Radiological assessment of treatment effectiveness of guided bone regeneration (GBR) method in postresectal and postcystal bone loss cases, observed for one year. Group of 25 patients (17 females and 8 males) who underwent root resection with cystectomy were evaluated. The following combination therapy of intraosseous deficits was used, consisting of bone augmentation with xenogenic material together with covering regenerative membranes and tight wound closure. The bone regeneration process was estimated, comparing the images taken on the day of the surgery and 12 months later, by means of Kodak RVG 6100 digital radiography set. The interpretation of the radiovisiographic image depends on the evaluation ability of the eye looking at it, which leaves a large margin of uncertainty. So, several texture analysis techniques were developed and used sequentially on the radiographic image. For each method, the results were the mean from the 25 images. These methods compute the fractal dimension (D), each one having its own theoretic basis. We used five techniques for calculating fractal dimension: power spectral density method, triangular prism surface area method, blanket method, intensity difference scaling method and variogram analysis. Our study showed a decrease of fractal dimension during the healing process after bone loss. We also found evidence that various methods of calculating fractal dimension give different results. During the healing process after bone loss, the surfaces of radiographic images became smooth. The result obtained show that our findings may be of great importance for diagnostic purpose.

  1. Ion Beam Sputtered Coatings of Bioglass

    NASA Technical Reports Server (NTRS)

    Hench, Larry L.; Wilson, J.; Ruzakowski, Patricia Henrietta Anne

    1982-01-01

    The ion beam sputtering technique available at the NASA-Lewis was used to apply coatings of bioglass to ceramic, metallic, and polymeric substrates. Experiments in vivo and in vitro described investigate these coatings. Some degree of substrate masking was obtained in all samples although stability and reactivity equivalent to bulk bioglass was not observed in all coated samples. Some degree of stability was seen in all coated samples that were reacted in vitro. Both metallic and ceramic substrates coated in this manner failed to show significantly improved coatings over those obtained with existing techniques. Implantation of the coated ceramic substrate samples in bone gave no definite bonding as seen with bulk glass; however, partial and patchy bonding was seen. Polymeric substrates in these studies showed promise of success. The coatings applied were sufficient to mask the underlying reactive test surface and tissue adhesion of collagen to bioglass was seen. Hydrophilic, hydrophobic, charged, and uncharged polymeric surfaces were successfully coated.

  2. Cementless Hydroxyapatite Coated Hip Prostheses

    PubMed Central

    Herrera, Antonio; Mateo, Jesús; Gil-Albarova, Jorge; Lobo-Escolar, Antonio; Ibarz, Elena; Gabarre, Sergio; Más, Yolanda

    2015-01-01

    More than twenty years ago, hydroxyapatite (HA), calcium phosphate ceramics, was introduced as a coating for cementless hip prostheses. The choice of this ceramic is due to its composition being similar to organic apatite bone crystals. This ceramic is biocompatible, bioactive, and osteoconductive. These qualities facilitate the primary stability and osseointegration of implants. Our surgical experience includes the implantation of more than 4,000 cementless hydroxyapatite coated hip prostheses since 1990. The models implanted are coated with HA in the acetabulum and in the metaphyseal area of the stem. The results corresponding to survival and stability of implants were very satisfactory in the long-term. From our experience, HA-coated hip implants are a reliable alternative which can achieve long term survival, provided that certain requirements are met: good design selection, sound choice of bearing surfaces based on patient life expectancy, meticulous surgical technique, and indications based on adequate bone quality. PMID:25802848

  3. Human peripheral blood leucocyte non-obese diabetic-severe combined immunodeficiency interleukin-2 receptor gamma chain gene mouse model of xenogeneic graft-versus-host-like disease and the role of host major histocompatibility complex

    PubMed Central

    King, M A; Covassin, L; Brehm, M A; Racki, W; Pearson, T; Leif, J; Laning, J; Fodor, W; Foreman, O; Burzenski, L; Chase, T H; Gott, B; Rossini, A A; Bortell, R; Shultz, L D; Greiner, D L

    2009-01-01

    Immunodeficient non-obese diabetic (NOD)-severe combined immune-deficient (scid) mice bearing a targeted mutation in the gene encoding the interleukin (IL)-2 receptor gamma chain gene (IL2rγnull) engraft readily with human peripheral blood mononuclear cells (PBMC). Here, we report a robust model of xenogeneic graft-versus-host-like disease (GVHD) based on intravenous injection of human PBMC into 2 Gy conditioned NOD-scid IL2rγnull mice. These mice develop xenogeneic GVHD consistently (100%) following injection of as few as 5 × 106 PBMC, regardless of the PBMC donor used. As in human disease, the development of xenogeneic GVHD is highly dependent on expression of host major histocompatibility complex class I and class II molecules and is associated with severely depressed haematopoiesis. Interrupting the tumour necrosis factor-α signalling cascade with etanercept, a therapeutic drug in clinical trials for the treatment of human GVHD, delays the onset and progression of disease. This model now provides the opportunity to investigate in vivo mechanisms of xenogeneic GVHD as well as to assess the efficacy of therapeutic agents rapidly. PMID:19659776

  4. Mid-Term Outcomes and Complications with Cementless Distal Locking Hip Revision Stem with Hydroxyapatite Coating for Proximal Bone Defects and Fractures.

    PubMed

    Carrera, Lluis; Haddad, Sleiman; Minguell, Joan; Amat, Carles; Corona, Pablo S

    2015-06-01

    We revised the first 100 revision total hip arthroplasties using a cementless distal locking revision stem conducted in our referral centre. Average follow-up was 9.2 years (range: 5.5-12 years). Harris Hip Score improved from 42.5 to 81.6, and none had thigh pain at last follow-up. No significant stress shielding, osteolysis, or radiologic loosening was found. All patients showed radiological evidence of secondary implant osseointegration. Overall survival was 97% with three patients being revised: two stem ruptures and one subsidence. We could trace these complications to technical errors. These findings suggest that a diaphyseal fixation of the revision stem with distal locking can provide the needed primary axial and rotational stability of the prosthesis. This would allow further bony ingrowth, enhanced by the hydroxyapatite coating.

  5. Aluminide coatings

    SciTech Connect

    Henager, Jr; Charles, H; Shin, Yongsoon; Samuels, William D

    2009-08-18

    Disclosed herein are aluminide coatings. In one embodiment coatings are used as a barrier coating to protect a metal substrate, such as a steel or a superalloy, from various chemical environments, including oxidizing, reducing and/or sulfidizing conditions. In addition, the disclosed coatings can be used, for example, to prevent the substantial diffusion of various elements, such as chromium, at elevated service temperatures. Related methods for preparing protective coatings on metal substrates are also described.

  6. COATED ALLOYS

    DOEpatents

    Harman, C.G.; O'Bannon, L.S.

    1958-07-15

    A coating is described for iron group metals and alloys, that is particularly suitable for use with nickel containing alloys. The coating is glassy in nature and consists of a mixture containing an alkali metal oxide, strontium oxide, and silicon oxide. When the glass coated nickel base metal is"fired'' at less than the melting point of the coating, it appears the nlckel diffuses into the vitreous coating, thus providing a closely adherent and protective cladding.

  7. Living Bones, Strong Bones

    NASA Video Gallery

    In this classroom activity, engineering, nutrition, and physical activity collide when students design and build a healthy bone model of a space explorer which is strong enough to withstand increas...

  8. Mesoporous titanium dioxide coating for metallic implants.

    PubMed

    Xia, Wei; Grandfield, Kathryn; Hoess, Andreas; Ballo, Ahmed; Cai, Yanling; Engqvist, Håkan

    2012-01-01

    A bioactive mesoporous titanium dioxide (MT) coating for surface drug delivery has been investigated to develop a multifunctional implant coating, offering quick bone bonding and biological stability. An evaporation induced self-assembly (EISA) method was used to prepare a mesoporous titanium dioxide coating of the anatase phase with BET surface area of 172 m(2)/g and average pore diameter of 4.3 nm. Adhesion tests using the scratch method and an in situ screw-in/screw-out technique confirm that the MT coating bonds tightly with the metallic substrate, even after removal from bone. Because of its high surface area, the bioactivity of the MT coating is much better than that of a dense TiO(2) coating of the same composition. Quick formation of hydroxyapatite (HA) in vitro can be related to enhance bonding with bone. The uptake of antibiotics by the MT coating reached 13.4 mg/cm(3) within a 24 h loading process. A sustained release behavior has been obtained with a weak initial burst. By using Cephalothin as a model drug, drug loaded MT coating exhibits a sufficient antibacterial effect on the material surface, and within millimeters from material surface, against E.coli. Additionally, the coated and drug loaded surfaces showed no cytotoxic effect on cell cultures of the osteoblastic cell line MG-63. In conclusion, this study describes a novel, biocompatiblemesoporous implant coating, which has the ability to induce HA formation and could be used as a surface drug-delivery system.

  9. Transgenic expression of human cytoxic T-lymphocyte associated antigen4-immunoglobulin (hCTLA4Ig) by porcine skin for xenogeneic skin grafting.

    PubMed

    Wang, Yong; Yang, Hua-Qiang; Jiang, Wen; Fan, Na-Na; Zhao, Ben-Tian; Ou-Yang, Zhen; Liu, Zhao-Ming; Zhao, Yu; Yang, Dong-Shan; Zhou, Xiao-Yang; Shang, Hai-Tao; Wang, Lu-Lu; Xiang, Peng-Ying; Ge, Liang-Peng; Wei, Hong; Lai, Liang-Xue

    2015-04-01

    Porcine skin is frequently used as a substitute of human skin to cover large wounds in clinic practice of wound care. In our previous work, we found that transgenic expression of human cytoxicT-lymphocyte associated antigen4-immunoglobulin (hCTLA4Ig) in murine skin graft remarkably prolonged its survival in xenogeneic wounds without extensive immunosuppression in recipients, suggesting that transgenic hCTLA4Ig expression in skin graft may be an effective and safe method to prolong xenogeneic skin graft survival. In this work, using a transgene construct containing hCTLA4Ig coding sequence under the drive of human Keratine 14 (k14) promoter, hCTLA4Ig transgenic pigs were generated by somatic nuclear transfer. The derived transgenic pigs were healthy and exhibited no signs of susceptibility to infection. The hCTLA4Ig transgene was stably transmitted through germline over generations, and thereby a transgenic pig colony was established. In the derived transgenic pigs, hCTLA4Ig expression in skin was shown to be genetically stable over generations, and detected in heart, kidney and corneal as well as in skin. Transgenic hCTLA4Ig protein in pigs exhibited expected biological activity as it suppressed human lymphocyte proliferation in human mixed lymphocyte culture to extents comparable to those of commercially purchased purified hCTLA4Ig protein. In skin grafting from pigs to rats, transgenic porcine skin grafts exhibited remarkably prolonged survival compared to the wild-type skin grafts derived from the same pig strain (13.33 ± 3.64 vs. 6.25 ± 2.49 days, P < 0.01), further indicating that the transgenic hCTLA4Ig protein was biologically active and capable of extending porcine skin graft survival in xenogeneic wounds. The transgenic pigs generated in this work can be used as a reproducible resource to provide porcine skin grafts with extended survival for wound coverage, and also as donors to investigate the impacts of hCTLA4Ig on xenotransplantation of other organs

  10. Engineering bone grafts with enhanced bone marrow and native scaffolds.

    PubMed

    Hung, Ben P; Salter, Erin K; Temple, Josh; Mundinger, Gerhard S; Brown, Emile N; Brazio, Philip; Rodriguez, Eduardo D; Grayson, Warren L

    2013-01-01

    The translation of tissue engineering approaches to the clinic has been hampered by the inability to find suitable multipotent cell sources requiring minimal in vitro expansion. Enhanced bone marrow (eBM), which is obtained by reaming long bone medullary canals and isolating the solid marrow putty, has large quantities of stem cells and demonstrates significant potential to regenerate bone tissues. eBM, however, cannot impart immediate load-bearing mechanical integrity or maintain the gross anatomical structure to guide bone healing. Yet, its putty-like consistency creates a challenge for obtaining the uniform seeding necessary to effectively combine it with porous scaffolds. In this study, we examined the potential for combining eBM with mechanically strong, osteoinductive trabecular bone scaffolds for bone regeneration by creating channels into scaffolds for seeding the eBM. eBM was extracted from the femurs of adult Yorkshire pigs using a Synthes reamer-irrigator-aspirator device, analyzed histologically, and digested to extract cells and characterize their differentiation potential. To evaluate bone tissue formation, eBM was seeded into the channels in collagen-coated or noncoated scaffolds, cultured in osteogenic conditions for 4 weeks, harvested and assessed for tissue distribution and bone formation. Our data demonstrates that eBM is a heterogenous tissue containing multipotent cell populations. Furthermore, coating scaffolds with a collagen hydrogel significantly enhanced cellular migration, promoted uniform tissue development and increased bone mineral deposition. These findings suggest the potential for generating customized autologous bone grafts for treating critical-sized bone defects by combining a readily available eBM cell source with decellularized trabecular bone scaffolds.

  11. Bone Cancer

    MedlinePlus

    Cancer that starts in a bone is uncommon. Cancer that has spread to the bone from another ... more common. There are three types of bone cancer: Osteosarcoma - occurs most often between ages 10 and ...

  12. Bone Diseases

    MedlinePlus

    Your bones help you move, give you shape and support your body. They are living tissues that rebuild constantly ... childhood and your teens, your body adds new bone faster than it removes old bone. After about ...

  13. Bone Metastasis

    MedlinePlus

    ... metastasis, surgeons can stabilize the bone using metal plates, screws and nails (orthopedic fixation). Orthopedic fixation can ... that can't be easily reinforced with metal plates or screws, such as pelvic bones and bones ...

  14. Co-delivery of platelet-derived growth factor (PDGF-BB) and bone morphogenic protein (BMP-2) coated onto heparinized titanium for improving osteoblast function and osteointegration.

    PubMed

    Kim, Sung Eun; Yun, Young-Pil; Lee, Jae Yong; Shim, June-Sung; Park, Kyeongsoon; Huh, Jung-Bo

    2015-12-01

    The aim of this study was to improve osteoblast function by delivering two growth factors, PDGF-BB and BMP-2, incorporated onto heparinized titanium (Hep-Ti) substrate. To achieve co-delivery of PDGF-BB and BMP-2, the surface of anodized Ti was immobilized with heparin, and then the two growth factors were coated onto the Hep-Ti surface. Incorporation of the two growth factors onto Hep-Ti was evaluated by SEM and XPS. Incorporated PDGF-BB and BMP-2 were released from the Hep-Ti substrate in a sustained manner. In vitro studies revealed that osteoblasts grown on PDGF-BB- and BMP-2-immobilized Hep-Ti increased ALP activity, calcium deposition, osteocalcin and osteopontin levels as compared to those grown on PDGF-BB alone- or BMP-2 alone-immobilized Hep-Ti. These results suggested that co-delivery of PDGF-BB and BMP-2 using Hep-Ti substrate will be a promising material for the enhancement of osteoblast function and osteointegration.

  15. Evaluation of Cross-presentation in Bone Marrow-derived Dendritic Cells in vitro and Splenic Dendritic Cells ex vivo Using Antigen-coated Beads

    PubMed Central

    Alloatti, Andrés; Kotsias, Fiorella; Hoffmann, Eik; Amigorena, Sebastian

    2017-01-01

    Antigen presentation by MHC class I molecules, also referred to as cross-presentation, elicits cytotoxic immune responses. In particular, dendritic cells (DC) are the most proficient cross-presenting cells, since they have developed unique means to control phagocytic and degradative pathways. This protocol allows the evaluation of antigen cross-presentation both in vitro (by using bone marrow-derived DC) and ex vivo (by purifying CD8+ DC from spleen after incorporation of particulate antigen) using ovalbumin (OVA)-coupled particles. Cross-presentation efficiency is measured by three different readouts: the B3Z hybridoma T cell line (Karttunen et al., 1992) and stimulation of antigen-specific CD8+ T cells (OT-I) (Kurts et al., 1996), either analyzing OT-I activation by CD69 expression or OT-I proliferation after labeling them with carboxyfluorescein succinimidyl ester (CFSE). By using this approach, we could show recently that DCs are able to increase cross-presentation efficiency transiently upon engagement of TLR4 (Alloatti et al., 2015). PMID:28239619

  16. Bone and bone turnover.

    PubMed

    Crofton, Patricia M

    2009-01-01

    Children with cancer are exposed to multiple influences that may adversely affect bone health. Some treatments have direct deleterious effects on bone whilst others may have indirect effects mediated through various endocrine abnormalities. Most clinical outcome studies have concentrated on survivors of acute lymphoblastic leukaemia (ALL). There is now good evidence that earlier treatment protocols that included cranial irradiation with doses of 24 Gy or greater may result in growth hormone deficiency and low bone mineral density (BMD) in the lumbar spine and femoral neck. Under current protocols, BMD decreases during intensive chemotherapy and fracture risk increases. Although total body BMD may eventually return to normal after completion of chemotherapy, lumbar spine trabecular BMD may remain low for many years. The implications for long-term fracture risk are unknown. Risk factors for low BMD include high dose methotrexate, higher cumulative doses of glucocorticoids, male gender and low physical activity. BMD outcome in non-ALL childhood cancers has been less well studied but there is evidence that survivors of childhood brain or bone tumours, and survivors of bone marrow transplants for childhood malignancy, all have a high risk of long-term osteopenia. Long-term follow-up is required, with appropriate treatment of any endocrine abnormalities identified.

  17. Influence of chronic L-DOPA treatment on immune response following allogeneic and xenogeneic graft in a rat model of Parkinson's disease.

    PubMed

    Breger, Ludivine S; Kienle, Korbinian; Smith, Gaynor A; Dunnett, Stephen B; Lane, Emma L

    2017-03-01

    Although intrastriatal transplantation of fetal cells for the treatment of Parkinson's disease had shown encouraging results in initial open-label clinical trials, subsequent double-blind studies reported more debatable outcomes. These studies highlighted the need for greater preclinical analysis of the parameters that may influence the success of cell therapy. While much of this has focused on the cells and location of the transplants, few have attempted to replicate potentially critical patient centered factors. Of particular relevance is that patients will be under continued L-DOPA treatment prior to and following transplantation, and that typically the grafts will not be immunologically compatible with the host. The aim of this study was therefore to determine the effect of chronic L-DOPA administered during different phases of the transplantation process on the survival and function of grafts with differing degrees of immunological compatibility. To that end, unilaterally 6-OHDA lesioned rats received sham surgery, allogeneic or xenogeneic transplants, while being treated with L-DOPA before and/or after transplantation. Irrespective of the L-DOPA treatment, dopaminergic grafts improved function and reduced the onset of L-DOPA induced dyskinesia. Importantly, although L-DOPA administered post transplantation was found to have no detrimental effect on graft survival, it did significantly promote the immune response around xenogeneic transplants, despite the administration of immunosuppressive treatment (cyclosporine). This study is the first to systematically examine the effect of L-DOPA on graft tolerance, which is dependent on the donor-host compatibility. These findings emphasize the importance of using animal models that adequately represent the patient paradigm.

  18. Characterisation of the Xenogeneic Immune Response to Microencapsulated Fetal Pig Islet-Like Cell Clusters Transplanted into Immunocompetent C57BL/6 Mice

    PubMed Central

    Ratnapala, Sabina; Foster, Jayne; Vaghjiani, Vijesh; Manuelpillai, Ursula; Tuch, Bernard E.

    2013-01-01

    Xenotransplantation of microencapsulated fetal pig islet-like cell clusters (FP ICCs) offers a potential cellular therapy for type 1 diabetes. Although microcapsules prevent direct contact of the host immune system with the xenografted tissue, poor graft survival is still an issue. This study aimed to characterise the nature of the host immune cells present on the engrafted microcapsules and effects on encapsulated FP ICCs that were transplanted into immunocompetent mice. Encapsulated FP ICCs were transplanted into the peritoneal cavity of C57BL/6 mice. Grafts retrieved at days 1, 3, 7, 14 and 21 post-transplantation were analysed for pericapsular fibrotic overgrowth (PFO), cell viability, intragraft porcine gene expression, macrophages, myofibroblasts and intraperitoneal murine cytokines. Graft function was assessed ex vivo by insulin secretion studies. Xenogeneic immune response to encapsulated FP ICCs was associated with enhanced intragraft mRNA expression of porcine antigens MIP-1α, IL-8, HMGB1 and HSP90 seen within the first two weeks post-transplantation. This was associated with the recruitment of host macrophages, infiltration of myofibroblasts and collagen deposition leading to PFO which was evident from day 7 post-transplantation. This was accompanied by a decrease in cell viability and loss of FP ICC architecture. The only pro-inflammatory cytokine detected in the murine peritoneal flushing was TNF-α with levels peaking at day 7 post transplantation. This correlated with the onset of PFO at day 7 implying activated macrophages as its source. The anti-inflammatory cytokines detected were IL-5 and IL-4 with levels peaking at days 1 and 7, respectively. Porcine C-peptide was undetectable at all time points post-transplantation. PFO was absent and murine intraperitoneal cytokines were undetectable when empty microcapsules were transplanted. In conclusion, this study demonstrated that the macrophages are direct effectors of the xenogeneic immune response to

  19. Allogeneic/xenogeneic transplantation of peptide-labeled mitochondria in Parkinson's disease: restoration of mitochondria functions and attenuation of 6-hydroxydopamine-induced neurotoxicity.

    PubMed

    Chang, Jui-Chih; Wu, Shey-Lin; Liu, Ko-Hung; Chen, Ya-Hui; Chuang, Chieh-Sen; Cheng, Fu-Chou; Su, Hong-Lin; Wei, Yau-Huei; Kuo, Shou-Jen; Liu, Chin-San

    2016-04-01

    Although restoration of mitochondrial function in mitochondrial diseases through peptide-mediated allogeneic mitochondrial delivery (PMD) has been demonstrated in vitro, the in vivo therapeutic efficacy of PMD in Parkinson's disease (PD) has yet to be determined. In this study, we compared the functionality of mitochondrial transfer with or without Pep-1 conjugation in neurotoxin (6-hydroxydopamine, 6-OHDA)-induced PC12 cells and PD rat models. We injected mitochondria into the medial forebrain bundle (MFB) of the PD rats after subjecting the nigrostriatal pathway to a unilateral 6-OHDA lesion for 21 days, and we verified the effectiveness of the mitochondrial graft in enhancing mitochondrial function in the soma of the substantia nigra (SN) neuron through mitochondrial transport dynamics in the nigrostriatal circuit. The result demonstrated that only PMD with allogeneic and xenogeneic sources significantly sustained mitochondrial function to resist the neurotoxin-induced oxidative stress and apoptotic death in the rat PC12 cells. The remaining cells exhibited a greater capability of neurite outgrowth. Furthermore, allogeneic and xenogeneic transplantation of peptide-labeled mitochondria after 3 months improved the locomotive activity in the PD rats. This increase was accompanied by a marked decrease in dopaminergic neuron loss in the substantia nigra pars compacta (SNc) and consistent enhancement of tyrosine hydroxylase-positive immunoreaction of dopaminergic neurons in the SNc and striatum. We also observed that in the SN dopaminergic neuron in the treated PD rats, mitochondrial complex I protein and mitochondrial dynamics were restored, thus ameliorating the oxidative DNA damage. Moreover, we determined signal translocation of graft allogeneic mitochondria from the MFB to the calbindin-positive SN neuron, which demonstrated the regulatory role of mitochondrial transport in alleviating 6-OHDA-induced degeneration of dopaminergic neurons.

  20. Multinucleated giant cells in the implant bed of bone substitutes are foreign body giant cells-New insights into the material-mediated healing process.

    PubMed

    Barbeck, Mike; Booms, Patrick; Unger, Ronald; Hoffmann, Verena; Sader, Robert; Kirkpatrick, Charles James; Ghanaati, Shahram

    2017-04-01

    In addition to macrophages, multinucleated giant cells (MNGCs) are involved in the tissue reaction to a variety of biomaterials. Especially in the case of bone substitute materials it has been assumed that the MNGCs are osteoclasts, based on the chemical and physical similarity of many materials to the calcified matrix and the bony environment in which they are used. However, many studies indicate that these cells belong to the cell line of the foreign body giant cells (FBGCs), which are of "inflammatory origin", although they have been shown to possess both a pro- and also anti-inflammatory phenotype. Moreover, no information is available about their role in the tissue reaction to bone substitute materials. The present study was conducted to analyze the origin of MNGCs in the implant beds of a synthetic and a xenogeneic bone substitute and focused on the application of immunohistochemical methods. Two antibodies against integrin molecules specific for osteoclasts (β-3 integrin) or FBGCs (β-2 integrin) were used to distinguish both giant cell types. The results of the present study indicate that the MNGCs induced by both kinds of bone substitutes are FBGCs, as they express only β-2 integrin in contrast to the osteoclasts outside of the immediate implantation areas, which only demonstrate β-3 integrin expression. These data give new insight into the tissue reaction to both xenogeneic and synthetic bone substitutes. Based on this new knowledge further research concerning the proteomic profile of the FBGCs especially based on the different physicochemical properties of bone substitutes is necessary. This may show that specific characteristics of bone substitutes may exhibit a substantial influence on the regeneration process via the expression of anti-inflammatory molecules by FBGCs. Based on this information it may be possible to formulate and choose bone substitutes that can guide the process of bone tissue regeneration on the molecular level. © 2017 Wiley

  1. Parathyroid Hormone-Induced Bone Marrow Mesenchymal Stem Cell Chondrogenic Differentiation and its Repair of Articular Cartilage Injury in Rabbits

    PubMed Central

    Chen, Yushu; Chen, Yi; Zhang, Shujiang; Du, Xiufan; Bai, Bo

    2016-01-01

    Background We explored the effect of parathyroid hormone (PTH)-induced bone marrow stem cells (BMSCs) complexed with fibrin glue (FG) in the repair of articular cartilage injury in rabbits. Material/Methods Forty-eight rabbits randomized into four groups were subjected to articular surgery (cartilage loss). The PTH and non-PTH intervention groups included transplantation with PTH/BMSC/FG xenogeneic and BMSC/FG xenogeneic complexes, respectively, into the injured area. The injured group contained no transplant while the control group comprised rabbits without any articular injury. Samples were monitored for cartilage repair up to three months post-surgery. Immunohistochemistry as well as real-time fluorescent quantitative PCR and Western blot were used to analyze the expression of type II collagen and aggrecan in the repaired tissue. Results At 12 weeks post-surgery, the loss of articular cartilage in the PTH group was fully repaired by hyaline tissue. Typical cartilage lacunae and intact subchondral bone were found. The boundary separating the surrounding normal cartilage tissue disappeared. The gross and International Cartilage Repair Society (ICRS) histological ranking of the repaired tissue was significantly higher in the PTH intervention group than in the non-PTH intervention and injury groups (p<0.05) without any significant difference compared to the control group (p>0.05). Type II collagen and aggrecan stained positive and the average optical density, relative mRNA expression and protein-integrated optical density in the PTH group were higher than in non-PTH and injured groups (p<0.05) but not significantly different from the control group (p>0.05). Conclusions PTH/BMSC/FG xenogeneic complexes effectively repaired the loss of cartilage in rabbit knee injury. PMID:27847384

  2. Preferential magnetic nanoparticle uptake by bone marrow derived macrophages sub-populations: effect of surface coating on polarization, toxicity, and in vivo MRI detection

    NASA Astrophysics Data System (ADS)

    Al Faraj, Achraf

    2013-07-01

    Noninvasive imaging of macrophages activity has raised increasing interest for diagnosis of different diseases, which make them attractive vehicles to deliver contrast agents or drugs for diagnostic or therapeutic purposes. In this study, the effect of polyethylene glycol functionalization of magnetic iron oxide nanoparticles and their further surface modification with carboxylic groups on bone marrow-derived M1 and M2 macrophages phenotype, labeling efficiency, uptake mechanism, biocompatibility, and their in vivo MR detection was assessed. An enhanced labeling efficiency was observed for carboxylic surface-modified superparamagnetic iron oxide (SPIO) compared to PEGylated SPIO and to a higher extent to plain SPIO along with a higher uptake by M2 subsets. Magnetic nanoparticles were found located in the periphery of the vesicles dispersed in the cytoplasm in TEM. Investigation of the labeling mechanism by inhibiting different uptake pathways revealed that endocytosis via scavenger receptor A, a process known to be clathrin mediated, plays a central role in the cellular uptake kinetics of both macrophages subpopulations. Biocompatibility evaluation showed no variation in cell viability and mitochondrial membrane potential with a low release of ROS. Flow cytometry and measurement of iNOS and Arginase 1 activity as marker of M1 and M2 macrophages polarization confirmed that magnetic labeling of macrophages subsets did not affect their polarization. In addition, no variation was observed in the biodistribution of magnetic iron oxide-labeled M1 and M2 macrophages subsets when monitored using noninvasive magnetic resonance imaging with a better detection for the enhanced SPIO-PEG-COOH-labeled cells.

  3. The Current Techniques for Preparing Bioglass Coatings

    NASA Astrophysics Data System (ADS)

    Zhao, Yafan; Chen, Chuanzhong; Wang, Diangang

    Bioglasses are promising alternatives as biomedical materials to repair or replace damaged parts of bones because of its good bioactivity and biocompatibility. It is possible to combine the bone-bonding ability of the bioglass surface with the high mechanical properties of the metallic substrate though the coating of metallic implants with bioglass. The principles and characteristics of some coating techniques, including sintering, plasma spray, sol-gel, electrophoresis deposition, ion beam assisted deposition and pulsed laser deposition, are introduced. Their current applications in preparing bioglass coatings are reviewed in detail. The future application trends are also reviewed.

  4. Bone marrow aspiration

    MedlinePlus

    Iliac crest tap; Sternal tap; Leukemia - bone marrow aspiration; Aplastic anemia - bone marrow aspiration; Myelodysplastic syndrome - bone marrow aspiration; Thrombocytopenia - bone marrow aspiration; Myelofibrosis - bone marrow aspiration

  5. Surface modification of implants in long bone.

    PubMed

    Förster, Yvonne; Rentsch, Claudia; Schneiders, Wolfgang; Bernhardt, Ricardo; Simon, Jan C; Worch, Hartmut; Rammelt, Stefan

    2012-01-01

    Coatings of orthopedic implants are investigated to improve the osteoinductive and osteoconductive properties of the implant surfaces and thus to enhance periimplant bone formation. By applying coatings that mimic the extracellular matrix a favorable environment for osteoblasts, osteoclasts and their progenitor cells is provided to promote early and strong fixation of implants. It is known that the early bone ongrowth increases primary implant fixation and reduces the risk of implant failure. This review presents an overview of coating titanium and hydroxyapatite implants with components of the extracellular matrix like collagen type I, chondroitin sulfate and RGD peptide in different small and large animal models. The influence of these components on cells, the inflammation process, new bone formation and bone/implant contact is summarized.

  6. Wear Performance of Laser Processed Tantalum Coatings

    PubMed Central

    Dittrick, Stanley; Balla, Vamsi Krishna; Bose, Susmita; Bandyopadhyay, Amit

    2011-01-01

    This first generation investigation evaluates the in vitro tribological performance of laser-processed Ta coatings on Ti for load-bearing implant applications. Linear reciprocating wear tests in simulated body fluid showed one order of magnitude less wear rate, of the order of 10−4mm3(N.m)−1, for Ta coatings compared to Ti. Our results demonstrate that Ta coatings can potentially minimize the early-stage bone-implant interface micro-motion induced wear debris generation due to their excellent bioactivity comparable to that of hydroxyapatite (HA), high wear resistance and toughness compared to popular HA coatings. PMID:22058608

  7. Comparison of Immunomodulation Properties of Porcine Mesenchymal Stromal/Stem Cells Derived from the Bone Marrow, Adipose Tissue, and Dermal Skin Tissue

    PubMed Central

    Ock, Sun-A; Baregundi Subbarao, Raghavendra; Lee, Yeon-Mi; Lee, Jeong-Hyeon; Jeon, Ryoung-Hoon; Lee, Sung-Lim; Park, Ji Kwon; Hwang, Sun-Chul; Rho, Gyu-Jin

    2016-01-01

    Mesenchymal stromal/stem cells (MSCs) demonstrate immunomodulation capacity that has been implicated in the reduction of graft-versus-host disease. Accordingly, we herein investigated the capacity of MSCs derived from several tissue sources to modulate both proinflammatory (interferon [IFN] γ and tumor necrosis factor [TNF] α) and immunosuppressive cytokines (transforming growth factor [TGF] β and interleukin [IL] 10) employing xenogeneic human MSC-mixed lymphocyte reaction (MLR) test. Bone marrow-derived MSCs showed higher self-renewal capacity with relatively slow proliferation rate in contrast to adipose-derived MSCs which displayed higher proliferation rate. Except for the lipoprotein gene, there were no marked changes in osteogenesis- and adipogenesis-related genes following in vitro differentiation; however, the histological marker analysis revealed that adipose MSCs could be differentiated into both adipose and bone tissue. TGFβ and IL10 were detected in adipose MSCs and bone marrow MSCs, respectively. However, skin-derived MSCs expressed both IFNγ and IL10, which may render them sensitive to immunomodulation. The xenogeneic human MLR test revealed that MSCs had a partial immunomodulation capacity, as proliferation of activated and resting peripheral blood mononuclear cells was not affected, but this did not differ among MSC sources. MSCs were not tumorigenic when introduced into immunodeficient mice. We concluded that the characteristics of MSCs are tissue source-dependent and their in vivo application requires more in-depth investigation regarding their precise immunomodulation capacities. PMID:26798368

  8. Superelastic Orthopedic Implant Coatings

    NASA Astrophysics Data System (ADS)

    Fournier, Eric; Devaney, Robert; Palmer, Matthew; Kramer, Joshua; El Khaja, Ragheb; Fonte, Matthew

    2014-07-01

    The demand for hip and knee replacement surgery is substantial and growing. Unfortunately, most joint replacement surgeries will fail within 10-25 years, thereby requiring an arduous, painful, and expensive revision surgery. To address this issue, a novel orthopedic implant coating material ("eXalt") has been developed. eXalt is comprised of super elastic nitinol wire that is knit into a three-dimensional spacer fabric structure. eXalt expands in vivo to conform to the implantation site and is porous to allow for bone ingrowth. The safety and efficacy of eXalt were evaluated through structural analysis, mechanical testing, and a rabbit implantation model. The results demonstrate that eXalt meets or exceeds the performance of current coating technologies with reduced micromotion, improved osseointegration, and stronger implant fixation in vivo.

  9. Bone Scan

    MedlinePlus

    ... Mayo Clinic Staff A bone scan is a nuclear imaging test that helps diagnose and track several ... you're nursing. A bone scan is a nuclear imaging procedure. In nuclear imaging, tiny amounts of ...

  10. Bone grafts.

    PubMed

    Hubble, Matthew J W

    2002-09-01

    Bone grafts are used in musculoskeletal surgery to restore structural integrity and enhance osteogenic potential. The demand for bone graft for skeletal reconstruction in bone tumor, revision arthroplasty, and trauma surgery, couple with recent advances in understanding and application of the biology of bone transplantation, has resulted in an exponential increase in the number of bone-grafting procedures performed over the last decade. It is estimated that 1.5 million bone-grafting procedures are currently performed worldwide each year, compared to a fraction of that number 20 years ago. Major developments also have resulted in the harvesting, storage, and use of bone grafts and production of graft derivatives, substitutes, and bone-inducing agents.

  11. Bone cement

    PubMed Central

    Vaishya, Raju; Chauhan, Mayank; Vaish, Abhishek

    2013-01-01

    The knowledge about the bone cement is of paramount importance to all Orthopaedic surgeons. Although the bone cement had been the gold standard in the field of joint replacement surgery, its use has somewhat decreased because of the advent of press-fit implants which encourages bone in growth. The shortcomings, side effects and toxicity of the bone cement are being addressed recently. More research is needed and continues in the field of nanoparticle additives, enhanced bone–cement interface etc. PMID:26403875

  12. Bone Analyzer

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The danger of disuse osteoporosis under weightless condition in space led to extensive research into measurements of bone stiffness and mass by the Biomedical Research Division of Ames and Stanford University. Through its Technology Utilization Program, NASA funded an advanced SOBSA, a microprocessor-controlled bone probe system. SOBSA determines bone stiffness by measuring responses to an electromagnetic shaker. With this information, a physician can identify bone disease, measure deterioration and prescribe necessary therapy. The system is now undergoing further testing.

  13. Bone Infections

    MedlinePlus

    ... bloodstream. People who are at risk for bone infections include those with diabetes, poor circulation, or recent injury to the bone. You may also be at risk if you are having hemodialysis. Symptoms of bone infections include Pain in the infected area Chills and ...

  14. Hydroxyapatite coatings.

    PubMed

    Lacefield, W R

    1988-01-01

    Four coating techniques were evaluated to determine which is most suitable for producing a dense, highly adherent coating onto metallic and ceramic implant materials. Two of the selected coating methods have serious limitations for use in this particular application, and did not meet the specified criteria for satisfactory coating as defined in the initial stages of the study. For example, the dip coating-sintering technique was judged to be unsatisfactory because of the adverse effect of the high-temperature sintering cycle on the mechanical properties of the metallic substrate materials. These materials could not be used in load-bearing applications because of the excessive grain growth and loss of the wrought structure of both the commercially pure Ti and Ti-6Al-4V substrates, and the loss of ductility in the cast Co-Cr-Mo alloy. Another area of concern was that bond strength between the HA coating and the substrate was not high enough to insure that interfacial failure would not occur during the lifetime of the implant. The immersion-coating technique, in which the metal substrate is immersed into the molten ceramic, was shown in a previous study to be the best method of coating a bioreactive glass onto a Co-Cr-Mo implant. Heating HA above its melting temperature, however, caused undesired compositional and structural changes, and upon solidification very limited adherence between the modified ceramic and substrate material occurred under the conditions of this study. The HIP technique, in which the Ti powder substrate and the HA powder coating are sintered together in a high-pressure autoclave, shows great promise for the fabrication of high-quality composite implants. Initial studies have indicated that high-density Ti substrates with a small grain size that are well bonded to a dense HA coating can be produced under optimum conditions. Sintering and densification additives, such as SiO2 powder, do not appear to be necessary. The main drawback to this

  15. Bone poroelasticity.

    PubMed

    Cowin, S C

    1999-03-01

    Poroelasticity is a well-developed theory for the interaction of fluid and solid phases of a fluid-saturated porous medium. It is widely used in geomechanics and has been applied to bone by many authors in the last 30 years. The purpose of this work is, first, to review the literature related to the application of poroelasticity to the interstitial bone fluid and, second, to describe the specific physical and modeling considerations that establish poroelasticity as an effective and useful model for deformation-driven bone fluid movement in bone tissue. The application of poroelasticity to bone differs from its application to soft tissues in two important ways. First, the deformations of bone are small while those of soft tissues are generally large. Second, the bulk modulus of the mineralized bone matrix is about six times stiffer than that of the fluid in the pores while the bulk moduli of the soft tissue matrix and the pore water are almost the same. Poroelasticity and electrokinetics can be used to explain strain-generated potentials in wet bone. It is noted that strain-generated potentials can be used as an effective tool in the experimental study of local bone fluid flow, and that the knowledge of this technique will contribute to the answers of a number of questions concerning bone mineralization, osteocyte nutrition and the bone mechanosensory system.

  16. Mixed zirconia calcium phosphate coatings for dental implants: tailoring coating stability and bioactivity potential.

    PubMed

    Pardun, Karoline; Treccani, Laura; Volkmann, Eike; Streckbein, Philipp; Heiss, Christian; Li Destri, Giovanni; Marletta, Giovanni; Rezwan, Kurosch

    2015-03-01

    Enhanced coating stability and adhesion are essential for long-term success of orthopedic and dental implants. In this study, the effect of coating composition on mechanical, physico-chemical and biological properties of coated zirconia specimens is investigated. Zirconia discs and dental screw implants are coated using the wet powder spraying (WPS) technique. The coatings are obtained by mixing yttria-stabilized zirconia (TZ) and hydroxyapatite (HA) in various ratios while a pure HA coating served as reference material. Scanning electron microscopy (SEM) and optical profilometer analysis confirm a similar coating morphology and roughness for all studied coatings, whereas the coating stability can be tailored with composition and is probed by insertion and dissections experiments in bovine bone with coated zirconia screw implants. An increasing content of calcium phosphate (CP) resulted in a decrease of mechanical and chemical stability, while the bioactivity increased in simulated body fluid (SBF). In vitro experiments with human osteoblast cells (HOB) revealed that the cells grew well on all samples but are affected by dissolution behavior of the studied coatings. This work demonstrates the overall good mechanical strength, the excellent interfacial bonding and the bioactivity potential of coatings with higher TZ contents, which provide a highly interesting coating for dental implants.

  17. Antagonistic effects of the staphylococcal enterotoxin a mutant, SEA(F47A/D227A), on psoriasis in the SCID-hu xenogeneic transplantation model.

    PubMed

    Boehncke, W H; Hardt-Weinelt, K; Nilsson, H; Wolter, M; Dohlsten, M; Ochsendorf, F R; Kaufmann, R; Antonsson, P

    2001-04-01

    Psoriasis is a T-cell-mediated immune dermatosis probably triggered by bacterial superantigens. This pathomechanism has been experimentally reproduced in a SCID-hu xenogeneic transplantation model. We analyzed the effects of different bacterial superantigens on the induction of psoriasis in this model. Staphylococcal enterotoxin B and exfoliative toxin triggered the onset of psoriasis when administered repetitively intracutaneously over a period of 2 wk, whereas staphylococcal enterotoxin A representing a distinct subfamily of staphylococcal enterotoxins only mimicked certain aspects of psoriasis. The biologic effects of staphylococcal enterotoxin A were more pronounced when a mutated form, SEA(H187A), of this superantigen with reduced affinity to major histocompatibility complex class II was coinjected. Another mutated variant, SEA(F47A/D227A), exhibiting no measurable major histocompatibility complex class II affinity blocked the effects triggered by wild-type staphylococcal enterotoxin A when injected in a 10-fold higher dose. Inhibition was specific as induction of psoriasiform epidermal changes by staphylococcal enterotoxin B could not be blocked. As staphylococcal enterotoxin A, in contrast to the other superantigens tested, is capable of inducing epidermal thickening but not the typical appearance of psoriasis, we conclude that bacterial superantigens may differ with regard to their effects on human nonlesional psoriatic skin. Staphylococcal-enterotoxin-A-mediated effects were blocked by a genetically engineered superantigen highlighting the potential therapeutic use of mutated superantigens.

  18. In situ application of hydrogel-type fibrin-islet composite optimized for rapid glycemic control by subcutaneous xenogeneic porcine islet transplantation.

    PubMed

    Kim, Jung-Sik; Lim, Jong-Hyung; Nam, Hye-Young; Lim, Hyun-Ju; Shin, Jun-Seop; Shin, Jin-Young; Ryu, Ju-Hee; Kim, Kwangmeyung; Kwon, Ick-Chan; Jin, Sang-Man; Kim, Hang-Rae; Kim, Sang-Joon; Park, Chung-Gyu

    2012-09-10

    Maximum engraftment of transplanted islets is essential for the clinical application of a subcutaneous site. Significant barriers to the current approaches are associated with their low effectiveness, complexity and unproven biosafety. Here, we evaluated and optimized a fibrin-islet composite for effective glycemic control in a subcutaneous site whose environment is highly hypoxic due to low vascularization potential. In the setting of xenogeneic porcine islet transplantation into the subcutaneous space of a diabetic mouse, the in vivo islet functions were greatly affected by the concentrations of fibrinogen and thrombin. The optimized hydrogel-type fibrin remarkably reduced the marginal islet mass to approximately one tenth that of islets without fibrin. This marginal islet mass was comparable to that in the setting of the subcapsular space of the kidney, which is a highly vascularized organ. Highly vascularized structures were generated inside and on the outer surface of the grafts. A hydrogel-type fibrin-islet composite established early diabetic control within an average of 3.4days after the transplantation. In the mechanistic studies, fibrin promoted local angiogenesis, enhanced islet viability and prevented fragmentation of islets into single cells. In conclusion, in situ application of hydrogel-type fibrin-islet composite may be a promising modality in the clinical success of subcutaneous islet transplantation.

  19. Stirred tank bioreactor culture combined with serum-/xenogeneic-free culture medium enables an efficient expansion of umbilical cord-derived mesenchymal stem/stromal cells.

    PubMed

    Mizukami, Amanda; Fernandes-Platzgummer, Ana; Carmelo, Joana G; Swiech, Kamilla; Covas, Dimas T; Cabral, Joaquim M S; da Silva, Cláudia L

    2016-08-01

    Mesenchymal stem/stromal cells (MSC) are being widely explored as promising candidates for cell-based therapies. Among the different human MSC origins exploited, umbilical cord represents an attractive and readily available source of MSC that involves a non-invasive collection procedure. In order to achieve relevant cell numbers of human MSC for clinical applications, it is crucial to develop scalable culture systems that allow bioprocess control and monitoring, combined with the use of serum/xenogeneic (xeno)-free culture media. In the present study, we firstly established a spinner flask culture system combining gelatin-based Cultispher(®) S microcarriers and xeno-free culture medium for the expansion of umbilical cord matrix (UCM)-derived MSC. This system enabled the production of 2.4 (±1.1) x10(5) cells/mL (n = 4) after 5 days of culture, corresponding to a 5.3 (±1.6)-fold increase in cell number. The established protocol was then implemented in a stirred-tank bioreactor (800 mL working volume) (n = 3) yielding 115 million cells after 4 days. Upon expansion under stirred conditions, cells retained their differentiation ability and immunomodulatory potential. The development of a scalable microcarrier-based stirred culture system, using xeno-free culture medium that suits the intrinsic features of UCM-derived MSC represents an important step towards a GMP compliant large-scale production platform for these promising cell therapy candidates.

  20. Regulatory Aspects of Coatings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter gives a history of the development and uses of edible coating regulations, detailed chapters on coating caracteristics, determination of coating properties, methods for making coatings, and discription of coating film formers (polysaccharieds, lipids, resins, proteins). The chapter also...

  1. Maxillary Sinus Augmentation Combining Bio-Oss with the Bone Marrow Aspirate Concentrate: A Histomorphometric Study in Humans

    PubMed Central

    Pasquali, Paulo José; Teixeira, Marcelo Lucchesi; de Oliveira, Thiago Altro; de Macedo, Luis Guilherme Scavone; Aloise, Antonio Carlos; Pelegrine, André Antonio

    2015-01-01

    Purpose. To investigate the regenerative results obtained with the association of bone marrow aspirate concentrate using the Bone Marrow Aspirate Concentrate (BMAC) method to a xenogeneic bone graft (Bio-Oss) in sinus floor elevation. Materials and Methods. Using a randomized controlled study design in eight consecutive patients (age of 55.4 ± 9.2 years), 16 sinus floor lift procedures were performed with Bio-Oss alone (control group, CG, n = 8) or combined with bone marrow aspirate concentrate obtained via the BMAC method (test group, TG, n = 8). Six months after the grafting procedures, bone biopsies were harvested during implant placement and were analyzed by histomorphometry. Results. Histomorphometric analysis revealed a significantly higher amount (p < 0.05) of vital mineralized tissue in TG when compared to the CG (55.15 ± 20.91% and 27.30 ± 5.55%, resp.). For nonvital mineralized tissue, TG presented a statistically higher level of Bio-Oss resorption (p < 0.05) when compared with the CG (6.32 ± 12.03% and 22.79 ± 9.60%, resp.). Both groups (TG and CG) showed no significantly different levels (p > 0.05) of nonmineralized tissue (38.53 ± 13.08% and 49.90 ± 7.64%, resp.). Conclusion. The use of bone marrow concentrate obtained by BMAC method increased bone formation in sinus lift procedures. PMID:26543482

  2. Production of porous coating on a prosthesis

    DOEpatents

    Sump, Kenneth R.

    1987-01-01

    Preselected surface areas of a prosthesis are covered by a blend of matching primary metallic particles and expendable particles. The particles are compressed and heated to assure that deformation and metallurgical bonding occurs between them and between the primary particles and the surface boundaries of the prosthesis. Porosity is achieved by removal of the expendable material. The result is a coating including discrete bonded particles separated by a network of interconnected voids presenting a homogeneous porous coating about the substrate. It has strength suitable for bone implant usage without intermediate adhesives, and adequate porosity to promote subsequent bone ingrowth.

  3. [Bone diseases].

    PubMed

    Uebelhart, Brigitte; Rizzoli, René

    2016-01-13

    Calcium intake shows a small impact on bone mineral density and fracture risk. Denosumab is a more potent inhibitor of bone resorption than zoledronate. Abaloparatide, PTHrP analog, increases bone mineral density and decreases fracture incidence. Teriparatide could be delivered via a transdermic device. Romosozumab and odanacatib improve calculated bone strength. Sequential or combined treatments with denosumab and teriparatide could be of interest, but not denosumab followed by teriparatide. Fibrous dysplasia, Paget disease and hypophosphatasia are updated, as well as atypical femoral fracture and osteonecrosis of the jaw.

  4. Bone cutting.

    PubMed

    Giraud, J Y; Villemin, S; Darmana, R; Cahuzac, J P; Autefage, A; Morucci, J P

    1991-02-01

    Bone cutting has always been a problem for surgeons because bone is a hard living material, and many osteotomes are still very crude tools. Technical improvement of these surgical tools has first been their motorization. Studies of the bone cutting process have indicated better features for conventional tools. Several non-conventional osteotomes, particularly ultrasonic osteotomes are described. Some studies on the possible use of lasers for bone cutting are also reported. Use of a pressurised water jet is also briefly examined. Despite their advantages, non-conventional tools still require improvement if they are to be used by surgeons.

  5. Structural bone allograft combined with genetically engineered mesenchymal stem cells as a novel platform for bone tissue engineering.

    PubMed

    Xie, Chao; Reynolds, David; Awad, Hani; Rubery, Paul T; Pelled, Gadi; Gazit, Dan; Guldberg, Robert E; Schwarz, Edward M; O'Keefe, Regis J; Zhang, Xinping

    2007-03-01

    The presence of live periosteal progenitor cells on the surface of bone autografts confers better healing than devitalized allograft. We have previously demonstrated in a murine 4 mm segmental femoral bone-grafting model that live periosteum produces robust endochondral and intramembraneous bone formation that is essential for effective healing and neovascularization of structural bone grafts. To the end of engineering a live pseudo-periosteum that could induce a similar response onto devitalized bone allograft, we seeded a mesenchymal stem cell line stably transfected with human bone morphogenic protein-2/beta-galactosidase (C9) onto devitalized bone allografts or onto a membranous small intestinal submucosa scaffold that was wrapped around the allograft. Histology showed that C9-coated allografts displayed early cartilaginous tissue formation at day 7. By 6 and 9 weeks, a new cortical shell was found bridging the segmental defect that united the host bones. Biomechanical testing showed that C9-coated allografts displayed torsional strength and stiffness equivalent to intact femurs at 6 weeks and superior to live isografts at 9 weeks. Volumetric and histomorphometric micro-computed tomography analyses demonstrated a 2-fold increase in new bone formation around C9-coated allografts, which resulted in a substantial increase in polar moment of inertia (pMOI) due to the formation of new cortical shell around the allografts. Positive correlations between biomechanics and new bone volume and pMOI were found, suggesting that the biomechanical function of the grafted femur relates to both morphological parameters. C9-coated allograft also exhibited slower resorption of the graft cortex at 9 weeks than live isograft. Both new bone formation and the persistent allograft likely contributed to the improved biomechanics of C9-coated allograft. Taken together, we propose a novel strategy to combine structural bone allograft with genetically engineered mesenchymal stem cells as

  6. Versatile Coating

    NASA Technical Reports Server (NTRS)

    1990-01-01

    A radome at Logan Airport and a large parabolic antenna at the Wang Building in Massachusetts are protected from weather, corrosion and ultraviolet radiation by a coating, specially designed for antennas and radomes, known as CRC Weathertite 6000. The CRC 6000 line that emerged from Boyd Coatings Research Co., Inc. is a solid dispersion of fluorocarbon polymer and polyurethane that yields a tough, durable film with superior ultraviolet resistance and the ability to repel water and ice over a long term. Additionally, it provides resistance to corrosion, abrasion, chemical attacks and impacts. Material can be used on a variety of substrates, such as fiberglass, wood, plastic and concrete in addition to steel and aluminum. In addition Boyd Coatings sees CRC 6000 applicability as an anti-icing system coated on the leading edge of aircraft wings.

  7. Protective Coating

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Inorganic Coatings, Inc.'s K-Zinc 531 protective coating is water-based non-toxic, non-flammable and has no organic emissions. High ratio silicate formula bonds to steel, and in 30 minutes, creates a very hard ceramic finish with superior adhesion and abrasion resistance. Improved technology allows application over a minimal commercial sandblast, fast drying in high humidity conditions and compatibility with both solvent and water-based topcoats. Coating is easy to apply and provides long term protection with a single application. Zinc rich coating with water-based potassium silicate binder offers cost advantages in materials, labor hours per application, and fewer applications over a given time span.

  8. Osseointegration of a hydroxyapatite-coated multilayered mesh stem.

    PubMed

    Kusakabe, Hiroshi; Sakamaki, Toyonori; Nihei, Kotaro; Oyama, Yasuo; Yanagimoto, Shigeru; Ichimiya, Masaru; Kimura, Jun; Toyama, Yoshiaki

    2004-07-01

    A new type of porous coating for hip prostheses called "multilayered mesh" was tested under weight-bearing conditions. The surface of the stem is constructed of titanium mesh produced by etching. The hip stems of hydroxyapatite (HA)-coated multilayered mesh and conventional beads were implanted into canine right hips, and animals were killed 3, 6 and 10 weeks and 6 and 12 months after implantation. Shear strength between the implant and the bone was evaluated by the push-out test. Bone ingrowth was calculated from backscattered electron imaging-scanning electron microscopy (BEI-SEM) images of transverse sections. Toluidine blue stained sections and the BEI-SEM images were evaluated histologically. The break sites of the specimens after the push-out test were evaluated on BEI-SEM images of longitudinal sections. The mean push-out strength of the HA-coated multilayered mesh samples was greater than that of the beads-coated samples every time tested, and the HA-coated multilayered mesh implants had significantly stronger push-out strength at 3 and 6 weeks (p<0.05). The strength of the HA-coated multilayered mesh implants was even greater at 6 and 12 months, whereas the strength of the beads-coated samples decreased. The HA-coated multilayered mesh implants showed significantly higher percentages of bone ingrowth than the beads-coated implants every time tested, except at 6 months (p<0.05). At 6 and 12 months, the bone ingrowth data for the HA-coated multilayered mesh implants increased, whereas it decreased for the beads-coated implants. The new bone formation had reached the bottom of the porous area of the HA-coated multilayered mesh surface by 3 weeks, but not had reached the bottom of the conventional beads surface. At 6 and 12 months, the smaller pores of the bead surface stopped the thickening of trabecular bone, and at 12 months, the break sites were at the bone-implant interface of the bead surface, whereas they were on the bone side of the HA-coated

  9. Bone marrow transplantation concurrently reconstitutes donor liver and immune system across host species barrier in mice.

    PubMed

    Qi, Ziping; Li, Lu; Wang, Xuefu; Gao, Xiang; Wang, Xin; Wei, Haiming; Zhang, Jian; Sun, Rui; Tian, Zhigang

    2014-01-01

    Liver immunopathologic mechanisms during hepatotropic infection, malignant transformation, and autoimmunity are still unclear. Establishing a chimeric mouse with a reconstituted liver and immune system derived from a single donor across species is critical to study regional donor immune responses in recipient liver. Using a strain of mice deficient in tyrosine catabolic enzyme fumarylacetoacetate hydrolase (fah-/-) and bone marrow transplantation (BMT), we reconstituted the donor's hepatocytes and immune cells across host species barrier. Syngeneic, allogeneic or even xenogeneic rat BMT rescued most recipient fah-/- mice against liver failure by donor BM-derived FAH+ hepatocytes. Importantly, immune system developed normally in chimeras, and the immune cells together with organ architecture were intact and functional. Thus, donor BM can across host species barrier and concurrently reconstitutes MHC-identical response between immune cells and hepatocytes, giving rise to a new simple and convenient small animal model to study donor's liver immune response in mice.

  10. Bone Marrow Transplantation Concurrently Reconstitutes Donor Liver and Immune System across Host Species Barrier in Mice

    PubMed Central

    Qi, Ziping; Li, Lu; Wang, Xuefu; Gao, Xiang; Wang, Xin; Wei, Haiming; Zhang, Jian; Sun, Rui; Tian, Zhigang

    2014-01-01

    Liver immunopathologic mechanisms during hepatotropic infection, malignant transformation, and autoimmunity are still unclear. Establishing a chimeric mouse with a reconstituted liver and immune system derived from a single donor across species is critical to study regional donor immune responses in recipient liver. Using a strain of mice deficient in tyrosine catabolic enzyme fumarylacetoacetate hydrolase (fah-/-) and bone marrow transplantation (BMT), we reconstituted the donor's hepatocytes and immune cells across host species barrier. Syngeneic, allogeneic or even xenogeneic rat BMT rescued most recipient fah-/- mice against liver failure by donor BM-derived FAH+ hepatocytes. Importantly, immune system developed normally in chimeras, and the immune cells together with organ architecture were intact and functional. Thus, donor BM can across host species barrier and concurrently reconstitutes MHC-identical response between immune cells and hepatocytes, giving rise to a new simple and convenient small animal model to study donor's liver immune response in mice. PMID:25191899

  11. Feeding NOD mice with pig splenocytes induces transferable mechanisms that modulate cellular and humoral xenogeneic reactions against pig spleen or islet cells

    PubMed Central

    YOU, S; GOUIN, E; SAÏ, P

    2002-01-01

    We have reported previously that oral administration of pig cells to NOD mice modified xenogeneic cellular response against pig islet cells (PICs), and hypothesized that it may have induced active suppression. This preliminary report evaluated only the effect of feeding pig cells by ‘primary’ proliferation, i.e. when splenocytes from fed mice are confronted with pig cells in vitro. The present study also considered ‘secondary’ proliferation and cytokine production after feeding and subsequent in vivo graft of pig cells. Additionally, serum IgM and IgG isotypes were quantified by ELISA using pig target cells. Induction of active mechanism by feeding was hypothetical, which led us here to transfer splenocytes from mice fed pig spleen cells (PSC) and evaluate ‘primary’ (after transfer) and ‘secondary’ (after transfer and subsequent graft of pig cells) proliferations and cytokine secretions in recipient mice. We also determined whether the effects of feeding pig cells persisted after depression of suppressor mechanisms by cyclophosphamide. Mice fed with PSC displayed increased ‘primary’ splenocyte proliferation to PSC or PIC (P < 0·0001), while ‘secondary’ responses were decreased (P < 0·03) in those fed PSC and subsequently grafted with PSC. The increased ‘primary’ and decreased ‘secondary’ proliferations were reduced (P < 0·04) by pretreatment with cyclophosphamide. The IL-10/ and IL-4/IFNγ ratios produced in response to PSC increased (P < 0·04) in mice fed and grafted with PSC compared to those grafted only with PSC. IgM and IgG levels against pig cells were, respectively, increased (P < 0·04) and decreased (P < 0·04) in mice fed and grafted with PSC. IgG2a and IgG2b, but not IgG1, levels were lower (P < 0·01). These effects of feeding PSC on ‘secondary’ proliferation, cytokine and antibody productions, were not detected when mice were fed PSC only after graft with PSC. Transfer with splenocytes from mice fed PSC increased

  12. Your Bones

    MedlinePlus

    ... shoulder blade or scapula (say: SKA-pyuh-luh), a large triangular bone on the upper back corner of each side of the ribcage. The arm is made up of three bones: the humerus (say: HYOO-muh-rus), which is above your elbow, and the radius (say: RAY-dee-us) and ulna (say: UL- ...

  13. Talking Bones.

    ERIC Educational Resources Information Center

    Johnson, Jaclyn; Kassing, Sharon

    2002-01-01

    Describes cooperation with the Saint Louis Zoo to provide opportunities for elementary school students to learn about bones, how animals move, what they eat, and how much they grow. Uses biofacts which include bones, skulls, and other parts to make the laboratory a hands-on experience for students. (YDS)

  14. Human neuroblastoma cell growth in xenogeneic hosts: comparison of T cell-deficient and NK-deficient hosts, and subcutaneous or intravenous injection routes.

    PubMed

    Turner, W J; Chatten, J; Lampson, L A

    1990-04-01

    We have examined two features of neuroblastoma cells that had not been well-characterized in a xenogeneic model: The cells display unusual immunologic properties in other experimental systems, and the original tumors display widespread and characteristic patterns of metastasis. To determine the most appropriate immunodeficient host for primary tumor growth, T cell-deficient nude mice, NK-deficient beige mice, beige-nudes, and controls were injected with the well-characterized line CHP-100. To define the pattern of tumor spread, complete autopsies were performed following subcutaneous, intraperitoneal and intravenous injections. CHP-100 consistently formed subcutaneous tumors in T cell-deficient mice (nude and beige-nude), but not in T cell-competent mice (beige, heterozygous nu/+ and bg/+, or wild-type). The growth rate and final size of the subcutaneous tumors were not greater in beige-nudes than in nudes. All mice showed early CHP-100 cell death after subcutaneous injection; the nature of the immunodeficiency was more relevant for the surviving subpopulation. Widespread dissemination was seen following intravenous injection, particularly in beige-nudes. Aspects of the growth patterns were appropriate to the tumor of origin. The behavior in immunodeficient mice suggests that T cells can play a role in controlling the growth of these cells; the next steps will be to define the effector mechanisms, and to determine if they can be exploited for human patients. The hematogenous spread following intravenous injection suggests that insights into the control of blood-borne tumor may also come from further study of this model.

  15. Repeated PD-1/PD-L1 monoclonal antibody administration induces fatal xenogeneic hypersensitivity reactions in a murine model of breast cancer

    PubMed Central

    Mall, Christine; Sckisel, Gail D.; Proia, David A.; Mirsoian, Annie; Grossenbacher, Steven K.; Pai, Chien-Chun Steven; Chen, Mingyi; Monjazeb, Arta M.; Kelly, Karen; Blazar, Bruce R.; Murphy, William J.

    2016-01-01

    ABSTRACT Monoclonal antibodies (mAbs) targeting coinhibitory molecules such as PD-1, PD-L1 and CTLA-4 are increasingly used as targets of therapeutic intervention against cancer. While these targets have led to a critical paradigm shift in treatments for cancer, these approaches are also plagued with limitations owing to cancer immune evasion mechanisms and adverse toxicities associated with continuous treatment. It has been difficult to reproduce and develop interventions to these limitations preclinically due to poor reagent efficacy and reagent xenogenecity not seen in human trials. In this study, we investigated adverse effects of repeated administration of PD-1 and PD-L1 mAbs in the murine 4T1 mammary carcinoma model. We observed rapid and fatal hypersensitivity reactions in tumor bearing mice within 30–60 min after 4–5 administrations of PD-L1 or PD-1 mAb but not CTLA-4 antibody treatment. These events occurred only in mice bearing the highly inflammatory 4T1 tumor and did not occur in mice bearing non-inflammatory tumors. We observed that mortality was associated with systemic accumulation of IgG1 antibodies, antibodies specific to the PD-1 mAb, and accumulation of Gr-1high neutrophils in lungs which have been implicated in the IgG mediated pathway of anaphylaxis. Anti-PD-1 associated toxicities were alleviated when PD-1 blockade was combined with the therapeutic HSP90 inhibitor, ganetespib, which impaired immune responses toward the xenogeneic PD-1 mAb. This study highlights a previously uncharacterized fatal hypersensitivity exacerbated by the PD-1/PD-L1 axis in the broadly used 4T1 tumor model as well as an interesting relationship between this particular class of checkpoint blockade and tumor-dependent immunomodulation. PMID:27057446

  16. Polydopamine-Assisted Surface Modification for Bone Biosubstitutes

    PubMed Central

    Zhou, Xin

    2016-01-01

    Polydopamine (PDA) prepared in the form of a layer of polymerized dopamine (DA) in a weak alkaline solution has been used as a versatile biomimetic surface modifier as well as a broadly used immobilizing macromolecule. This review mainly discusses the progress of biomaterial surface modification inspired by the participation of PDA in bone tissue engineering. A comparison between PDA-assisted coating techniques and traditional surface modification applied to bone tissue engineering is first presented. Secondly, the chemical composition and the underlying formation mechanism of PDA coating layer as a unique surface modifier are interpreted and discussed. Furthermore, several typical examples are provided to evidence the importance of PDA-assisted coating techniques in the construction of bone biosubstitutes and the improvement of material biocompatibility. Nowadays, the application of PDA as a superior surface modifier in multifunctional biomaterials is drawing tremendous interests in bone tissue scaffolds to promote the osteointegration for bone regeneration. PMID:27595097

  17. Engineered PlyCB as Novel Implant Coating for Osseointegration

    DTIC Science & Technology

    2011-09-01

    for visualization by fluorescent microscopy in later aims. Next, we tested the binding of mutants to hydroxyapatite (HA) under various salt, pH...osteoblast, hydroxyapatite , titanium implant, bioactive coating 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF...or shortened lifespan under physiological loads. Coatings such as hydroxyapatite , the mineral component of bone, are often used to promote

  18. Long-term rabbits bone response to titanium implants in the presence of inorganic bovine-derived graft.

    PubMed

    Munhoz, Etiene Andrade; Bodanezi, Augusto; Cestari, Tania Mary; Taga, Rumio; de Carvalho, Paulo Sergio Perri; Ferreira, Osny

    2012-07-01

    This study evaluated bone responses to titanium implants in the presence of an inorganic graft material. The bilateral mandible incisors of 24 rabbits were surgically extracted and one of the exposed sockets, chosen at random, was filled with an inorganic xenogenic bone graft (Gen-ox®), whereas the remaining socket was left to heal naturally and served as a control. After 60 days, titanium implants were inserted in the specific areas, and on days 0, 30, 60, and 180 after the implant insertions, six animals of each group were killed. Digital periapical radiography of implant region was obtained and vertical bone height (VBH) and bone density (BD) were evaluated by digital analysis system. In the undecalcified tissue cuts, bone-to-implant contact (BIC) and bone area (BA) within the limits of the implant threads were evaluated and compared statistically by means of two-way ANOVA and Tukey's test (ρ < 0.05). No significant differences were detected in VBH and BA, either between groups or between different experimental intervals. The BD was significantly higher in the experimental group than in the control group in all the intervals tested, but there were no significant differences by interval. The BIC was statistically lower in the control group on day 0; however, a significant increase was observed on days 60 and 180 (ρ < 0.05). The use of an inorganic xenograft prior to insertion of a titanium implant did not interfere with the course of osseointegration.

  19. Effects of sodium hydroxide, sodium hypochlorite, and gaseous hydrogen peroxide on the natural properties of cancellous bone.

    PubMed

    Bi, Long; Li, De-Cheng; Huang, Zhao-Song; Yuan, Zhi

    2013-07-01

    Processed xenegeneic cancellous bone represents an alternative to bone autograft. In order to observe the effects of present prion inactivation treatments on the natural properties of xenogeneic cancellous bones, we treated bovine bone granules with sodium hydroxide (NaOH), sodium hypochlorite (NaOCl), and gaseous hydrogen peroxide (gH2 O2 ) respectively in this study. The microstructure, composition, and mineral content of the granules were evaluated by scanning electron micrograph, energy dispersive X-ray spectroscopy, ash analysis, and micro-computed tomography. The biomechanical property was analyzed by a materials testing machine. The cytocompatibility was evaluated by using a mouse fibroblast cell line (3T3). The microstructure, organic content, and mechanical strength were dramatically altered at the surface of bone in both NaOH- and NaOCl-treated groups, but not in the gH2 O2 -treated group. Compared with the gH2 O2 -treated group, attachment and proliferation of 3T3 were reduced in either NaOH- or NaOCl-treated groups. As the consequence, gH2 O2 treatment may be a useful approach of disinfection for the preparation of natural cancellous bone with well-preserved structural, mechanical, and biological properties.

  20. Preparing hydroxyapatite-silicon composite suspensions with homogeneous distribution of multi-walled carbon nano-tubes for electrophoretic coating of NiTi bone implant and their effect on the surface morphology

    NASA Astrophysics Data System (ADS)

    Khalili, Vida; Khalil-Allafi, Jafar; Xia, Wei; Parsa, Alireza B.; Frenzel, Jan; Somsen, Christoph; Eggeler, Gunther

    2016-03-01

    Preparing a stable suspension is a main step towards the electrophoretically depositing of homogeneous and dense composite coatings on NiTi for its biomedical application. In the present study, different composite suspensions of hydroxyapatite, silicon and multi-walled carbon nano-tubes were prepared using n-butanol and triethanolamine as media and dispersing agent, respectively. Multi-walled carbon nanotubes were first functionalized in the nitric acid vapor for 15 h at 175 °C, and then mixed into suspensions. Thermal desorption spectroscopy profiles indicate the formation of functional groups on multi-walled carbon nano-tubes. An excellent suspension stability can be achieved for different amounts of triethanolamine. The amount of triethanolamine can be increased by adding a second component to a stable hydroxyapatite suspension due to an electrostatic interaction between components in suspension. The stability of composite suspension is less than that of the hydroxyapatite suspension, due to density differences, which under the gravitational force promote the demixing. The scanning electron microscopy images of the coatings surface show that more dense coatings are developed on NiTi substrate using electrophoretic deposition and sintering at 850 °C in the simultaneous presence of silicon and multi-walled carbon nanotubes in the hydroxyapatite coatings. The atomic force microscopy results of the coatings surface represent that composite coatings of hydroxyapatite-20 wt.% silicon and hydroxyapatite-20 wt.% silicon-1 wt.% multi-walled carbon nano-tubes with low zeta potential have rougher surfaces.

  1. Diamond Coatings

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Advances in materials technology have demonstrated that it is possible to get the advantages of diamond in a number of applications without the cost penalty, by coating and chemically bonding an inexpensive substrate with a thin film of diamond-like carbon (DLC). Diamond films offer tremendous technical and economic potential in such advances as chemically inert protective coatings; machine tools and parts capable of resisting wear 10 times longer; ball bearings and metal cutting tools; a broad variety of optical instruments and systems; and consumer products. Among the American companies engaged in DLC commercialization is Diamonex, Inc., a diamond coating spinoff of Air Products and Chemicals, Inc. Along with its own proprietary technology for both polycrystalline diamond and DLC coatings, Diamonex is using, under an exclusive license, NASA technology for depositing DLC on a substrate. Diamonex is developing, and offering commercially, under the trade name Diamond Aegis, a line of polycrystalline diamond-coated products that can be custom tailored for optical, electronic and engineering applications. Diamonex's initial focus is on optical products and the first commercial product is expected in late 1990. Other target applications include electronic heat sink substrates, x-ray lithography masks, metal cutting tools and bearings.

  2. Paget's Disease of Bone

    MedlinePlus

    ... page please turn Javascript on. Paget's Disease of Bone What is Paget's Disease of Bone? Click for more information Enlarged and Misshapen Bones Paget's disease of bone causes affected bones to ...

  3. Osteoclastic resorption of biomimetic calcium phosphate coatings in vitro.

    PubMed

    Leeuwenburgh, S; Layrolle, P; Barrère, F; de Bruijn, J; Schoonman, J; van Blitterswijk, C A; de Groot, K

    2001-08-01

    A new biomimetic method for coating metal implants enables the fast formation of dense and homogeneous calcium phosphate coatings. Titanium alloy (Ti6Al4V) disks were coated with a thin, carbonated, amorphous calcium phosphate (ACP) by immersion in a saturated solution of calcium, phosphate, magnesium, and carbonate. The ACP-coated disks then were processed further by incubation in calcium phosphate solutions to produce either crystalline carbonated apatite (CA) or octacalcium phosphate (OCP). The resorption behavior of these three biomimetic coatings was studied using osteoclast-enriched mouse bone-marrow cell cultures for 7 days. Cell-mediated degradation was observed for both carbonated apatite and octacalcium phosphate coatings. Numerous resorption lacunae characteristic of osteoclastic resorption were found on carbonated apatite after cell culture. The results showed that carbonated apatite coatings are resorbed by osteoclasts in a manner consistent with normal osteoclastic resorption. Osteoclasts also degraded the octacalcium phosphate coatings but not by classical pit formation.

  4. Bone densitometry.

    PubMed

    Chun, Kwang J

    2011-05-01

    Conventional radiographic methods allow physicians to visualize bone structure. However, they do not offer information on the bone mineral density (BMD), which can facilitate early diagnosis and treatment of osteoporosis. Bone densitometry, by contrast, helps to detect bone mineral loss at an early stage because it provides accurate quantitative measurement of BMD. With an emphasis on quantification, shorter scanning time and precision, scientists have been developing BMD measurement devices that use absorption technique. They first developed single-energy absorptiometry (single-photon absorptiometry) by using I-125, which could measure BMD of peripheral bones. Single-photon absorptiometry was replaced by dual-energy absorptiometry (dual photon absorptiometry [DPA]) that used gadolinium-153. DPA had greater accuracy in measuring the BMD of central skeletal bones. Single-energy x-ray absorptiometry was also developed but it had limitations in measuring central skeletal BMD. In the mid-1980s, dual-energy x-ray absorptiometry (DXA) was introduced and widely accepted for the early detection, treatment, and follow-up study of osteoporosis. There are several reasons for the popularity. DXA can measure BMD of posteroanterior spine and hip in a much shorter time than DPA while being capable of measuring BMD of peripheral bones. Other advantages include very low radiation doses to the patients, high image resolution, precision, and stable calibration of the instruments. In recent years, DXA has also been applied to lateral spine for the density of trabecular bone, to the whole body for the measurement of total body bone density and for the body composition, and to the spine for the vertebral fracture assessment. Still, posteroanterior spine and hip scans remain the most common applications of DXA because data on the normal range of BMD of the skeletal sites for different age, sex, and ethnic groups are compiled and made available with the devices, which gives the physician

  5. Nanostructured Coatings

    NASA Astrophysics Data System (ADS)

    Rivière, J.-P.

    In many branches of technology where surfaces are playing a growing role, the use of coatings is often the only way to provide surfaces with specific functional properties. For example, the austenitic stainless steels or titanium alloys exhibit poor resistance to wear and low hardness values, which limits the field of applications. The idea then is to develop new solutions which would improve the mechanical performance and durability of objects used in contact and subjected to mechanical forces in hostile gaseous or liquid environments. Hard coatings are generally much sought after to enhance the resistance to wear and corrosion. They are of particular importance because they constitute a class of protective coatings which is already widely used on an industrial scale to improve the hardness and lifetime of cutting tools.

  6. Protective Coatings

    NASA Technical Reports Server (NTRS)

    1980-01-01

    General Magnaplate Corporation's pharmaceutical machine is used in the industry for high speed pressing of pills and capsules. Machine is automatic system for molding glycerine suppositories. These machines are typical of many types of drug production and packaging equipment whose metal parts are treated with space spinoff coatings that promote general machine efficiency and contribute to compliance with stringent federal sanitation codes for pharmaceutical manufacture. Collectively known as "synergistic" coatings, these dry lubricants are bonded to a variety of metals to form an extremely hard slippery surface with long lasting self lubrication. The coatings offer multiple advantages; they cannot chip, peel or be rubbed off. They protect machine parts from corrosion and wear longer, lowering maintenance cost and reduce undesired heat caused by power-robbing friction.

  7. Gold Coating

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Epner Technology Inc. responded to a need from Goddard Space Flight Center for the ultimate in electroplated reflectivity needed for the Mars Global Surveyor Mars Orbiter Laser Altimeter (MOLA). Made of beryllium, the MOLA mirror was coated by Epner Technology Laser Gold process, specially improved for the project. Improved Laser Gold- coated reflectors have found use in an epitaxial reactor built for a large semiconductor manufacturer as well as the waveguide in Braun-Thermoscan tympanic thermometer and lasing cavities in various surgical instruments.

  8. Substituted hydroxyapatites for bone repair.

    PubMed

    Shepherd, Jennifer H; Shepherd, David V; Best, Serena M

    2012-10-01

    Calcium phosphates such as hydroxyapatite have a wide range of applications both in bone grafts and for the coating of metallic implants, largely as a result of their chemical similarity to the mineral component of bone. However, to more accurately mirror the chemistry, various substitutions, both cationic (substituting for the calcium) and anionic (substituting for the phosphate or hydroxyl groups) have been produced. Significant research has been carried out in the field of substituted apatites and this paper aims to summarise some of the key effect of substitutions including magnesium, zinc, strontium, silicon and carbonate on physical and biological characteristics. Even small substitutions have been shown to have very significant effects on thermal stability, solubility, osteoclastic and osteoblastic response in vitro and degradation and bone regeneration in vivo.

  9. Interpreting Bones.

    ERIC Educational Resources Information Center

    Weymouth, Patricia P.

    1986-01-01

    Describes an activity which introduces students to the nature and challenges of paleoanthropology. In the exercise, students identify diagrammed bones and make interpretations about the creature. Presents questions and tasks employed in the lesson. (ML)

  10. Bone and bone marrow: the same organ.

    PubMed

    Del Fattore, Andrea; Capannolo, Marta; Rucci, Nadia

    2010-11-01

    Interplays between bone and bone marrow are not limited to merely anatomic and histological connections, but include a tight functional correlation. Bone marrow resides within the medullary cavity of the bones and the process of hematopoiesis is regulated, at least in part, by bone cells. Moreover, osteoclasts and osteoblasts derive from precursors of hematopoietic and mesenchymal origin, respectively, both residing within the bone marrow. Alterations in one of these components typically cause impairment in the other, so diseases of the bone marrow compartment often affect the bone and vice versa. All these findings could make us to speculate that bone and bone marrow are not two separate districts, but can be considered as the two elements of the same unique functional unit, the bone-bone marrow organ. Here we will describe histological and functional interplays between bone and bone marrow, and will illustrate some diseases in which this tight correlation is evident.

  11. Volumetric analysis of bone substitute material performance within the human sinus cavity of former head and neck cancer patients: A prospective, randomized clinical trial

    PubMed Central

    Lorenz, Jonas; Eichler, Kathrin; Barbeck, Mike; Lerner, Henriette; Stübinger, Stefan; Seipel, Catherine; Vogl, Thomas J.; Kovács, Adorján F.; Ghanaati, Shahram; Sader, Robert A.

    2016-01-01

    Background: In numerous animal and human studies, it could be detected that in bone augmentation procedures, material's physicochemical characteristics can influence the cellular inflammatory pattern and therefore the integration in the host tissue. Histological, histomorphometrical, and clinical analyses of the integration of the biomaterial in the surrounding tissue are well established methodologies; however, they do not make a statement on volume and density changes of the augmented biomaterial. Aims: The aim of the present study was to assess the volume and density of a xenogeneic (Bio-Oss®, BO) and a synthetic (NanoBone®, NB) bone substitute material in split-mouth sinus augmentations in former tumor patients to complete histological and histomorphometrical assessment. Methods: Immediately and 6 months after sinus augmentation computed tomography scans were recorded, bone grafts were marked, and the volume was calculated with radiologic RIS-PACS software (General Electric Healthcare, Chalfont St. Giles, Great Britain) to determine the integration and degradation behavior of both biomaterials. Results: Radiographic analysis revealed a volume reduction of the initial augmented bone substitute material (i.e. 100%) to 77.36 (±11.68) % in the BO-group, respectively, 75.82 (±22.28) % in the NB-group six months after augmentation. In both materials, the volume reduction was not significant. Bone density significantly increased in both groups. Conclusion: The presented radiological investigation presents a favorable method to obtain clinically relevant information concerning the integration and degradation behavior of bone substitute materials. PMID:28299254

  12. Mesenchymal Stem Cells and Nano-Bioceramics for Bone Regeneration.

    PubMed

    Kankilic, Berna; Köse, Sevil; Korkusuz, Petek; Timuçin, Muharrem; Korkusuz, Feza

    Orthopedic disorders and trauma usually result in bone loss. Bone grafts are widely used to replace this tissue. Bone grafts excluding autografts unfortunately have disadvantages like evoking immune response, contamination and rejection. Autografts are of limited sources and optimum biomaterials that can replace bone have been searched for several decades. Bioceramics, which have the similar inorganic structure of natural bone, are widely used to regenerate bone or coat metallic implants. As people continuously look for a higher life quality, there are developments in technology almost everyday to meet their expectations. Nanotechnology is one of such technologies and it attracts everyone's attention in biomaterial science. Nano scale biomaterials have many advantages like larger surface area and higher biocompatibility and these properties make them more preferable than micro scale. Also, stem cells are used for bone regeneration besides nano-bioceramics due to their differentiation characteristics. This review covers current research on nano-bioceramics and mesenchymal stem cells and their role in bone regeneration.

  13. Upregulation of CC Chemokine Receptor 7 (CCR7) Enables Migration of Xenogeneic Human Adipose-Derived Mesenchymal Stem Cells to Rat Secondary Lymphoid Organs.

    PubMed

    Ma, Tian; Luan, Shao-Liang; Huang, Hong; Sun, Xing-Kun; Yang, Yan-Mei; Zhang, Hui; Han, Wei-Dong; Li, Hong; Han, Yan

    2016-12-30

    BACKGROUND CC chemokine receptor 7 (CCR7) expression is vital for cell migration to secondary lymphoid organs (SLOs). Our previous work showed that inducing CCR7 expression enabled syngeneic mesenchymal stem cells (MSCs) to migrate into SLOs, resulting in enhanced immunosuppressive performance in mice. Given that human adipose-derived stem cells (hASCs) are widely used in clinical therapy, we further investigated whether upregulation of CCR7 enables xenogeneic hASCs to migrate to rat SLOs. MATERIAL AND METHODS hASCs rarely express CCR7; therefore, hASCs were transfected with lentivirus encoding rat CCR7 (rCCR7) plus green fluorescence protein (GFP) or GFP alone. CCR7 mRNA and cell surface expression of rCCR7-hASCs and GFP-hASCs were examined by reverse transcription-polymerase chain reaction (RT-PCR) and flow cytometry (FCM), respectively. The phenotype, differentiation, and proliferation capacity of each cell type was also determined. To examine migration, rCCR7-hASCs and GFP-hASCs were injected intravenously into Lewis rats, and the proportion of GFP-positive cells in the spleen and lymph nodes was determined with FCM. RESULTS mRNA and cell surface protein expression of CCR7 was essentially undetectable in hASCs and GFP-ASCs; however, CCR7 was highly expressed in rCCR7-ASCs. rCCR7-hASCs, GFP-hASCs, and hASCs shared a similar immunophenotype, and maintained the ability of multilineage differentiation and proliferation. In addition, the average proportion of GFP-positive cells was significantly higher following transplantation of rCCR7-hASCs compared with GFP-hASCs (p<0.01). CONCLUSIONS These results suggest that upregulation of rat CCR7 expression does not change the phenotype, differentiation, or proliferation capacity of hASCs, but does enable efficient migration of hASCs to rat SLOs.

  14. Upregulation of CC Chemokine Receptor 7 (CCR7) Enables Migration of Xenogeneic Human Adipose-Derived Mesenchymal Stem Cells to Rat Secondary Lymphoid Organs

    PubMed Central

    Ma, Tian; Luan, Shao-Liang; Huang, Hong; Sun, Xing-Kun; Yang, Yan-Mei; Zhang, Hui; Han, Wei-dong; Li, Hong; Han, Yan

    2016-01-01

    Background CC chemokine receptor 7 (CCR7) expression is vital for cell migration to secondary lymphoid organs (SLOs). Our previous work showed that inducing CCR7 expression enabled syngeneic mesenchymal stem cells (MSCs) to migrate into SLOs, resulting in enhanced immunosuppressive performance in mice. Given that human adipose-derived stem cells (hASCs) are widely used in clinical therapy, we further investigated whether upregulation of CCR7 enables xenogeneic hASCs to migrate to rat SLOs. Material/Methods hASCs rarely express CCR7; therefore, hASCs were transfected with lentivirus encoding rat CCR7 (rCCR7) plus green fluorescence protein (GFP) or GFP alone. CCR7 mRNA and cell surface expression of rCCR7-hASCs and GFP-hASCs were examined by reverse transcription-polymerase chain reaction (RT-PCR) and flow cytometry (FCM), respectively. The phenotype, differentiation, and proliferation capacity of each cell type was also determined. To examine migration, rCCR7-hASCs and GFP-hASCs were injected intravenously into Lewis rats, and the proportion of GFP-positive cells in the spleen and lymph nodes was determined with FCM. Results mRNA and cell surface protein expression of CCR7 was essentially undetectable in hASCs and GFP-ASCs; however, CCR7 was highly expressed in rCCR7-ASCs. rCCR7-hASCs, GFP-hASCs, and hASCs shared a similar immunophenotype, and maintained the ability of multilineage differentiation and proliferation. In addition, the average proportion of GFP-positive cells was significantly higher following transplantation of rCCR7-hASCs compared with GFP-hASCs (p<0.01). Conclusions These results suggest that upregulation of rat CCR7 expression does not change the phenotype, differentiation, or proliferation capacity of hASCs, but does enable efficient migration of hASCs to rat SLOs. PMID:28035134

  15. Control of surface topography in biomimetic calcium phosphate coatings.

    PubMed

    Costa, Daniel O; Allo, Bedilu A; Klassen, Robert; Hutter, Jeffrey L; Dixon, S Jeffrey; Rizkalla, Amin S

    2012-02-28

    The behavior of cells responsible for bone formation, osseointegration, and bone bonding in vivo are governed by both the surface chemistry and topography of scaffold matrices. Bone-like apatite coatings represent a promising method to improve the osteoconductivity and bonding of synthetic scaffold materials to mineralized tissues for regenerative procedures in orthopedics and dentistry. Polycaprolactone (PCL) films were coated with calcium phosphates (CaP) by incubation in simulated body fluid (SBF). We investigated the effect of SBF ion concentration and soaking time on the surface properties of the resulting apatite coatings. CaP coatings were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), and energy dispersive X-ray spectrometry (EDX). Young's modulus (E(s)) was determined by nanoindentation, and surface roughness was assessed by atomic force microscopy (AFM) and mechanical stylus profilometry. CaP such as carbonate-substituted apatite were deposited onto PCL films. SEM and AFM images of the apatite coatings revealed an increase in topographical complexity and surface roughness with increasing ion concentration of SBF solutions. Young's moduli (E(s)) of various CaP coatings were not significantly different, regardless of the CaP phase or surface roughness. Thus, SBF with high ion concentrations may be used to coat synthetic polymers with CaP layers of different surface topography and roughness to improve the osteoconductivity and bone-bonding ability of the scaffold.

  16. Bone Densitometry (Bone Density Scan)

    MedlinePlus

    ... and display the bone density measurements on a computer monitor. top of page How is the procedure performed? ... passed over the area, generating images on a computer monitor. You must hold very still and may be ...

  17. Study on the neotype zirconia's implant coated nanometer hydroxyapatite ceramics

    NASA Astrophysics Data System (ADS)

    Zhu, J. W.; Yang, D. W.

    2007-07-01

    In recent years, biologic ceramics is a popular material of implants and bioactive surface modification of dental implant became a research emphasis, which aims to improve bioactivity of implants materials and acquire firmer implants-bone interface. The zirconia ceramic has excellent mechanical properties and nanometer HA ceramics is a bioceramic well known for its bioactivity, therefore, nanometer HA ceramics coating on zirconia, allows combining the excellent mechanical properties of zirconia substrates with its bioactivity. This paper shows a new method for implant shape design and bioactive modification of dental implants surface. Zirconia's implant substrate was prepared by sintered method, central and lateral tunnels were drilled in the zirconia hollow porous cylindrical implants by laser processing. The HA powders and needle-like HA crystals were made by a wet precipitation and calcining method. Its surface was coated with nanometer HA ceramics which was used brush HA slurry and vacuum sintering. Mechanical testing results revealed that the attachment strength of nanometer HA ceramics coated zirconia samples is high. SEM and interface observation after inserted experiment indicated that calcium and phosphor content increased and symmetrically around coated implant-bone tissue interface. A significantly higher affinity index was demonstrated in vivo by histomorphometric evaluation in coated versus uncoated implants. SEM analysis demonstrated better bone adhesion to the material in coated implant at any situation. In addition, the hollow porous cylindrical implant coated with nanometer HA ceramics increase the interaction of bone and implant, the new bone induced into the surface of hollow porous cylindrical implant and through the most tunnels filled into central hole. The branch-like structure makes the implant and bone a body, which increased the contact area and decreased elastic ratio. Therefore, the macroscopical and microcosmic nested structure of

  18. Bone marrow transplant

    MedlinePlus

    Transplant - bone marrow; Stem cell transplant; Hematopoietic stem cell transplant; Reduced intensity nonmyeloablative transplant; Mini transplant; Allogenic bone marrow transplant; Autologous bone marrow transplant; ...

  19. Characterization of bone marrow mononuclear cells on biomaterials for bone tissue engineering in vitro.

    PubMed

    Henrich, Dirk; Verboket, René; Schaible, Alexander; Kontradowitz, Kerstin; Oppermann, Elsie; Brune, Jan C; Nau, Christoph; Meier, Simon; Bonig, Halvard; Marzi, Ingo; Seebach, Caroline

    2015-01-01

    Bone marrow mononuclear cells (BMCs) are suitable for bone tissue engineering. Comparative data regarding the needs of BMC for the adhesion on biomaterials and biocompatibility to various biomaterials are lacking to a large extent. Therefore, we evaluated whether a surface coating would enhance BMC adhesion and analyze the biocompatibility of three different kinds of biomaterials. BMCs were purified from human bone marrow aspirate samples. Beta tricalcium phosphate (β-TCP, without coating or coated with fibronectin or human plasma), demineralized bone matrix (DBM), and bovine cancellous bone (BS) were assessed. Seeding efficacy on β-TCP was 95% regardless of the surface coating. BMC demonstrated a significantly increased initial adhesion on DBM and β-TCP compared to BS. On day 14, metabolic activity was significantly increased in BMC seeded on DBM in comparison to BMC seeded on BS. Likewise increased VEGF-synthesis was observed on day 2 in BMC seeded on DBM when compared to BMC seeded on BS. The seeding efficacy of BMC on uncoated biomaterials is generally high although there are differences between these biomaterials. Beta-TCP and DBM were similar and both superior to BS, suggesting either as suitable materials for spatial restriction of BMC used for regenerative medicine purposes in vivo.

  20. Extracellular Vesicle-functionalized Decalcified Bone Matrix Scaffolds with Enhanced Pro-angiogenic and Pro-bone Regeneration Activities

    PubMed Central

    Xie, Hui; Wang, Zhenxing; Zhang, Liming; Lei, Qian; Zhao, Aiqi; Wang, Hongxiang; Li, Qiubai; Cao, Yilin; Jie Zhang, Wen; Chen, Zhichao

    2017-01-01

    Vascularization is crucial for bone regeneration after the transplantation of tissue-engineered bone grafts in the clinical setting. Growing evidence suggests that mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) are potently pro-angiogenic both in vitro and in vivo. In the current study, we fabricated a novel EV-functionalized scaffold with enhanced pro-angiogenic and pro-bone regeneration activities by coating decalcified bone matrix (DBM) with MSC-derived EVs. EVs were harvested from rat bone marrow-derived MSCs and the pro-angiogenic potential of EVs was investigated in vitro. DBM scaffolds were then coated with EVs, and the modification was verified by scanning electron microscopy and confocal microscopy. Next, the pro-angiogenic and pro-bone regeneration activities of EV-modified scaffolds were evaluated in a subcutaneous bone formation model in nude mice. Micro-computed tomography scanning analysis showed that EV-modified scaffolds with seeded cells enhanced bone formation. Enhanced bone formation was confirmed by histological analysis. Immunohistochemical staining for CD31 proved that EV-modified scaffolds promoted vascularization in the grafts, thereby enhancing bone regeneration. This novel scaffold modification method provides a promising way to promote vascularization, which is essential for bone tissue engineering. PMID:28367979

  1. COATING METHOD

    DOEpatents

    Townsend, R.G.

    1959-08-25

    A method is described for protectively coating beryllium metal by etching the metal in an acid bath, immersing the etched beryllium in a solution of sodium zincate for a brief period of time, immersing the beryllium in concentrated nitric acid, immersing the beryhlium in a second solution of sodium zincate, electroplating a thin layer of copper over the beryllium, and finally electroplating a layer of chromium over the copper layer.

  2. Broken Bones (For Parents)

    MedlinePlus

    ... Feeding Your 1- to 2-Year-Old Broken Bones KidsHealth > For Parents > Broken Bones Print A A ... bone fragments in place. When Will a Broken Bone Heal? Fractures heal at different rates, depending upon ...

  3. Bone lesion biopsy

    MedlinePlus

    Bone biopsy; Biopsy - bone ... the cut, then pushed and twisted into the bone. Once the sample is obtained, the needle is ... sample is sent to a lab for examination. Bone biopsy may also be done under general anesthesia ...

  4. Bone biopsy (image)

    MedlinePlus

    A bone biopsy is performed by making a small incision into the skin. A biopsy needle retrieves a sample of bone and it ... examination. The most common reasons for bone lesion biopsy are to distinguish between benign and malignant bone ...

  5. Surgery for Bone Cancer

    MedlinePlus

    ... amputation. This is called limb-salvage or limb-sparing surgery . In going over treatment options, it is ... 2016 Treating Bone Cancer Surgery for Bone Cancer Radiation Therapy for Bone Cancer Chemotherapy for Bone Cancer Targeted ...

  6. Facts about Broken Bones

    MedlinePlus

    ... Room? What Happens in the Operating Room? Broken Bones KidsHealth > For Kids > Broken Bones Print A A ... sticking through the skin . What Happens When a Bone Breaks? It hurts to break a bone! It's ...

  7. Microwave-induced biomimetic approach for hydroxyapatite coatings of chitosan scaffolds.

    PubMed

    Kaynak Bayrak, Gökçe; Demirtaş, T Tolga; Gümüşderelioğlu, Menemşe

    2017-02-10

    Simulated body fluid (SBF) can form calcium phosphates on osteoinductive materials, so it is widely used for coating of bone scaffolds to mimic natural extracellular matrix (ECM). However, difficulties of bulk coating in 3D scaffolds and the necessity of long process times are the common problems for coating with SBF. In the present study, a microwave-assisted process was developed for rapid and internal coating of chitosan scaffolds. The scaffolds were fabricated as superporous hydrogel (SPH) by combining microwave irradiation and gas foaming methods. Then, they were immersed into 10x  SBF-like solution and homogenous bone-like hydroxyapatite (HA) coating was achieved by microwave treatment at 600W without the need of any nucleating agent. Cell culture studies with MC3T3-E1 preosteoblasts showed that microwave-assisted biomimetic HA coating process could be evaluated as an efficient and rapid method to obtain composite scaffolds for bone tissue engineering.

  8. Thermal radiative properties: Coatings.

    NASA Technical Reports Server (NTRS)

    Touloukian, Y. S.; Dewitt, D. P.; Hernicz, R. S.

    1972-01-01

    This volume consists, for the most part, of a presentation of numerical data compiled over the years in a most comprehensive manner on coatings for all applications, in particular, thermal control. After a moderately detailed discussion of the theoretical nature of the thermal radiative properties of coatings, together with an overview of predictive procedures and recognized experimental techniques, extensive numerical data on the thermal radiative properties of pigmented, contact, and conversion coatings are presented. These data cover metallic and nonmetallic pigmented coatings, enamels, metallic and nonmetallic contact coatings, antireflection coatings, resin coatings, metallic black coatings, and anodized and oxidized conversion coatings.

  9. The cultivation of human multipotent mesenchymal stromal cells in clinical grade medium for bone tissue engineering.

    PubMed

    Pytlík, Robert; Stehlík, David; Soukup, Tomás; Kalbácová, Marie; Rypácek, Frantisek; Trc, Tomás; Mulinková, Katarína; Michnová, Petra; Kideryová, Linda; Zivný, Jan; Klener, Pavel; Veselá, Romana; Trnený, Marek; Klener, Pavel

    2009-07-01

    Clinical application of human multipotent mesenchymal stromal cells (hMSCs) requires their expansion to be safe and rapid. We aimed to develop an expansion protocol which would avoid xenogeneic proteins, including fetal calf serum (FCS), and which would shorten the cultivation time and avoid multiple passaging. First, we have compared research-grade alpha-MEM medium with clinical grade CellGro for Hematopoietic Cells' Medium. When FCS was used for supplementation and non-adherent cells were discarded, both media were comparable. Both media were comparable also when pooled human serum (hS) was used instead of FCS, but the numbers of hMSCs were lower when non-adherent cells were discarded. However, significantly more hMSCs were obtained both in alpha-MEM and in CellGro supplemented with hS when the non-adherent cells were left in the culture. Furthermore, addition of recombinant cytokines and other supplements (EGF, PDGF-BB, M-CSF, FGF-2, dexamethasone, insulin and ascorbic acid) to the CellGro co-culture system with hS led to 40-fold increase of hMSCs' yield after two weeks of cultivation compared to alpha-MEM with FCS. The hMSCs expanded in the described co-culture system retain their osteogenic, adipogenic and chondrogenic differentiation potential in vitro and produce bone-like mineralized tissue when propagated on 3D polylactide scaffolds in immunodeficient mice. Our protocol thus allows for very effective one-step, xenogeneic protein-free expansion of hMSCs, which can be easily transferred into good manufacturing practice (GMP) conditions for large-scale, clinical-grade production of hMSCs for purposes of tissue engineering.

  10. LRBA is Essential for Allogeneic Responses in Bone Marrow Transplantation

    PubMed Central

    Park, Mi Young; Sudan, Raki; Srivastava, Neetu; Neelam, Sudha; Youngs, Christie; Wang, Jia-Wang; Engelman, Robert W.; Kerr, William G.

    2016-01-01

    The PH-BEACH-WD40 (PBW) protein family members play a role in coordinating receptor signaling and intracellular vesicle trafficking. LPS-Responsive-Beige-like Anchor (LRBA) is a PBW protein whose immune function remains elusive. Here we show that LRBA-null mice are viable, but exhibit compromised rejection of allogeneic, xenogeneic and missing self bone-marrow grafts. Further, we demonstrate that LRBA-null Natural Killer (NK) cells exhibit impaired signaling by the key NK activating receptors, NKp46 and NKG2D. However, induction of IFN-γ by cytokines remains intact, indicating LRBA selectively facilitates signals by receptors for ligands expressed on the surface of NK targets. Surprisingly, LRBA limits immunoregulatory cell numbers in tissues where GvHD is primed or initiated, and consistent with this LRBA-null mice also demonstrate resistance to lethal GvHD. These findings demonstrate that LRBA is redundant for host longevity while being essential for both host and donor-mediated immune responses and thus represents a unique and novel molecular target in transplant immunology. PMID:27824136

  11. A novel graded bioactive high adhesion implant coating

    NASA Astrophysics Data System (ADS)

    Brohede, Ulrika; Zhao, Shuxi; Lindberg, Fredrik; Mihranyan, Albert; Forsgren, Johan; Strømme, Maria; Engqvist, Håkan

    2009-06-01

    One method to increase the clinical success rate of metal implants is to increase their bone bonding properties, i.e. to develop a bone bioactive surface leading to reduced risks of interfacial problems. Much research has been devoted to modifying the surface of metals to make them become bioactive. Many of the proposed methods include depositing a coating on the implant. However, there is a risk of coating failure due to low substrate adhesion. This paper describes a method to obtain bioactivity combined with a high coating adhesion via a gradient structure of the coating. Gradient coatings were deposited on Ti (grade 5) using reactive magnetron sputtering with increasing oxygen content. To increase the grain size in the coating, all coatings were post annealed at 385 °C. The obtained coating exhibited a gradual transition over 70 nm from crystalline titanium oxide (anatase) at the surface to metallic Ti in the substrate, as shown using cross-section transmission electron microscopy and X-ray photoelectron spectroscopy depth profiling. Using scratch testing, it could be shown that the adhesion to the substrate was well above 1 GPa. The bioactivity of the coating was verified in vitro by the spontaneous formation of hydroxylapatite upon storage in phosphate buffer solution at 37 °C for one week. The described process can be applied to implants irrespective of bulk metal in the base and should introduce the possibility to create safer permanent implants like reconstructive devices, dental, or spinal implants.

  12. Carbon nanotubes functionalized with fibroblast growth factor accelerate proliferation of bone marrow-derived stromal cells and bone formation

    NASA Astrophysics Data System (ADS)

    Hirata, Eri; Ménard-Moyon, Cécilia; Venturelli, Enrica; Takita, Hiroko; Watari, Fumio; Bianco, Alberto; Yokoyama, Atsuro

    2013-11-01

    Multi-walled carbon nanotubes (MWCNTs) were functionalized with fibroblast growth factor (FGF) and the advantages of their use as scaffolds for bone augmentation were evaluated in vitro and in vivo. The activity of FGF was assessed by measuring the effect on the proliferation of rat bone marrow stromal cells (RBMSCs). The presence of FGF enhanced the proliferation of RBMSCs and the FGF covalently conjugated to the nanotubes (FGF-CNT) showed the same effect as FGF alone. In addition, FGF-CNT coated sponges were implanted between the parietal bone and the periosteum of rats and the formation of new bone was investigated. At day 14 after implantation, a larger amount of newly formed bone was clearly observed in most pores of FGF-CNT coated sponges. These findings indicated that MWCNTs accelerated new bone formation in response to FGF, as well as the integration of particles into new bone during its formation. Scaffolds coated with FGF-CNT could be considered as promising novel substituting materials for bone regeneration in future tissue engineering applications.

  13. NICKEL COATED URANIUM ARTICLE

    DOEpatents

    Gray, A.G.

    1958-10-01

    Nickel coatings on uranium and various methods of obtaining such coatings are described. Specifically disclosed are such nickel or nickel alloy layers as barriers between uranium and aluminum- silicon, chromium, or copper coatings.

  14. Bacterial adhesion to bisphosphonate coated hydroxyapatite.

    PubMed

    Ganguli, A; Steward, C; Butler, S L; Philips, G J; Meikle, S T; Lloyd, A W; Grant, M H

    2005-04-01

    Staphylococcus aureus (S. aureus) is commonly associated with microbial infection of orthopaedic implants. Such infections often lead to osteomyelitis, which may result in failure of the implant due to localised bone destruction. Bacterial adhesion and subsequent colonisation of the device may occur as a consequence of contamination during surgery, or by seeding from a distant site through the blood circulation. Coating of the hydroxyapatite (HA) ceramic component of artificial hip joints with the bisphosphonates clodronate (C) and pamidronate (P) has been proposed as a means to minimise osteolysis and thereby prevent loosening of the implant. However, the effect of the bisphosphonate coating on bacterial adhesion to the HA materials must be determined before this approach can be implemented. In this study coated HA materials were incubated with the S. aureus and the number of adherent bacteria determined using the Modified Vortex Device (MVD) method. The number of bacteria adherent to the P coated HA material was significantly greater than that adherent to uncoated HA (60-fold increase) or to the C coated HA (90-fold increase). Therefore, even though earlier studies suggested that P bound to HA may improve osseointegration, the results presented would suggest that the use of this coating may be limited by the potential increased susceptibility of the coated device to infection.

  15. A Review Paper on Biomimetic Calcium Phosphate Coatings

    PubMed Central

    Lin, X.; de Groot, K.; Wang, D.; Hu, Q.; Wismeijer, D.; Liu, Y.

    2015-01-01

    Biomimetic calcium phosphate coatings have been developed for bone regeneration and repair because of their biocompatibility, osteoconductivity, and easy preparation. They can be rendered osteoinductive by incorporating an osteogenic agent, such as bone morphogenetic protein 2 (BMP-2), into the crystalline lattice work in physiological situations. The biomimetic calcium phosphate coating enables a controlled, slow and local release of BMP-2 when it undergoes cell mediated coating degradation induced by multinuclear cells, such as osteoclasts and foreign body giant cells, which mimics a physiologically similar release mode, to achieve sustained ectopic or orthotopic bone formation. Therefore, biomimetic calcium phosphate coatings are considered to be a promising delivery vehicle for osteogenic agents. In this review, we present an overview of biomimetic calcium phosphate coatings including their preparation techniques, physico-chemical properties, potential as drug carrier, and their pre-clinical application both in ectopic and orthotopic animal models. We briefly review some features of hydroxyapatite coatings and their clinical applications to gain insight into the clinical applications of biomimetic calcium phosphate coatings in the near future. PMID:25893016

  16. Effects of calcium phosphate composition in sputter coatings on in vitro and in vivo performance.

    PubMed

    Urquia Edreira, Eva R; Wolke, Joop G C; Aldosari, Abdullah AlFarraj; Al-Johany, Sulieman S; Anil, Sukumaran; Jansen, John A; van den Beucken, Jeroen J J P

    2015-01-01

    Calcium phosphate (CaP) ceramic coatings have been used to enhance the biocompatibility and osteoconductive properties of metallic implants. The chemical composition of these ceramic coatings is an important parameter, which can influence the final bone performance of the implant. In this study, the effect of phase composition of CaP-sputtered coatings was investigated on in vitro dissolution behavior and in vivo bone response. Coatings were prepared by a radio frequency (RF) magnetron sputtering technique; three types of CaP target materials were used to obtain coatings with different stoichiometry and calcium to phosphate ratios (hydroxyapatite (HA), α-tricalciumphosphate (α-TCP), and tetracalciumphosphate (TTCP)) were compared with non-coated titanium controls. The applied ceramic coatings were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and inductively coupled plasma optical emission spectroscopy. The in vitro dissolution/precipitation of the CaP coatings was evaluated using immersion tests in simulated body fluid (SBF). To mimic the in vivo situation, identical CaP coatings were also evaluated in a femoral condyle rabbit model. TCPH and TTCPH showed morphological changes during 4-week immersion in SBF. The results of bone implant contact (BIC) and peri-implant bone volume (BV) showed a similar response for all experimental coatings. An apparent increase in tartrate resistant acid phosphatase (TRAP) positive staining was observed in the peri-implant region with decreasing coating stability. In conclusion, the experimental groups showed different coating properties when tested in vitro and an apparent increase in bone remodeling with increasing coating dissolution in vivo.

  17. Corrosion resistant coating

    DOEpatents

    Wrobleski, Debra A.; Benicewicz, Brian C.; Thompson, Karen G.; Bryan, Coleman J.

    1997-01-01

    A method of protecting a metal substrate from corrosion including coating a metal substrate of, e.g., steel, iron or aluminum, with a conductive polymer layer of, e.g., polyaniline, coating upon said metal substrate, and coating the conductive polymer-coated metal substrate with a layer of a topcoat upon the conductive polymer coating layer, is provided, together with the resultant coated article from said method.

  18. Corrosion resistant coating

    DOEpatents

    Wrobleski, D.A.; Benicewicz, B.C.; Thompson, K.G.; Bryan, C.J.

    1997-08-19

    A method of protecting a metal substrate from corrosion including coating a metal substrate of, e.g., steel, iron or aluminum, with a conductive polymer layer of, e.g., polyaniline, coating upon said metal substrate, and coating the conductive polymer-coated metal substrate with a layer of a topcoat upon the conductive polymer coating layer, is provided, together with the resultant coated article from said method.

  19. Hot isostatic pressing-processed hydroxyapatite-coated titanium implants: light microscopic and scanning electron microscopy investigations.

    PubMed

    Wie, H; Herø, H; Solheim, T

    1998-01-01

    Hot isostatic pressing (HIP) was used in a new procedure to produce hydroxyapatite (HA) coatings on a commercially pure titanium (cpTi) substrate for osseous implantation. Eighteen HIP-processed HA-coated implants were placed in the inferior border of the mandibles in 2 Labrador retriever dogs and left submerged for 3 months. As control specimens, 12 sandblasted cpTi implants were placed in the same mandibles and, to compare the bone reaction, 2 additional plasma-sprayed HA-coated implants (Integral) were placed. Tissue reactions at the bony interfaces of the implants were studied in ground sections with the implants in situ, using ordinary, fluorescent, and polarized light microscopy and scanning electron microscopy (SEM). The HIP-processed HA coatings displayed an increased density in light microscopy and SEM as compared to plasma-sprayed coatings. Direct bone-implant contact was found in all 3 types of surfaces. However, the production of new bone was far more abundant for the HA-coated implants than for sandblasted cpTi implants. The presence of bone-forming and bone-resorbing cells indicated active bone remodeling in the interface area at 3 months after implant placement. The present results support the view that epitaxial bone growth may occur from the HA-coated implant surface. It was concluded that the increased density of the present HIP-processed HA material does not reduce the bioactive properties of the coatings.

  20. Bone image segmentation.

    PubMed

    Liu, Z Q; Liew, H L; Clement, J G; Thomas, C D

    1999-05-01

    Characteristics of microscopic structures in bone cross sections carry essential clues in age determination in forensic science and in the study of age-related bone developments and bone diseases. Analysis of bone cross sections represents a major area of research in bone biology. However, traditional approaches in bone biology have relied primarily on manual processes with very limited number of bone samples. As a consequence, it is difficult to reach reliable and consistent conclusions. In this paper we present an image processing system that uses microstructural and relational knowledge present in the bone cross section for bone image segmentation. This system automates the bone image analysis process and is able to produce reliable results based on quantitative measurements from a large number of bone images. As a result, using large databases of bone images to study the correlation between bone structural features and age-related bone developments becomes feasible.

  1. Intravenous administration of xenogenic adipose-derived mesenchymal stem cells (ADMSC) and ADMSC-derived exosomes markedly reduced brain infarct volume and preserved neurological function in rat after acute ischemic stroke

    PubMed Central

    Wallace, Christopher Glenn; Yuen, Chun-Man; Kao, Gour-Shenq; Chen, Yi-Ling; Shao, Pei-Lin; Chen, Yung-Lung; Chai, Han-Tan; Lin, Kun-Chen; Liu, Chu-Feng; Chang, Hsueh-Wen; Lee, Mel S.; Yip, Hon-Kan

    2016-01-01

    We tested the hypothesis that combined xenogenic (from mini-pig) adipose-derived mesenchymal stem cell (ADMSC) and ADMSC-derived exosome therapy could reduce brain-infarct zone (BIZ) and enhance neurological recovery in rat after acute ischemic stroke (AIS) induced by 50-min left middle cerebral artery occlusion. Adult-male Sprague-Dawley rats (n = 60) were divided equally into group 1 (sham-control), group 2 (AIS), group 3 [AIS-ADMSC (1.2×106 cells)], group 4 [AIS-exosome (100μg)], and group 5 (AIS-exosome-ADMSC). All therapies were provided intravenously at 3h after AIS procedure. BIZ determined by histopathology (by day-60) and brain MRI (by day-28) were highest in group 2, lowest in group 1, higher in groups 3 and 4 than in group 5, but they showed no difference between groups 3 and 4 (all p < 0.0001). By day-28, sensorimotor functional results exhibited an opposite pattern to BIZ among the five groups (p < 0.005). Protein expressions of inflammatory (inducible nitric oxide synthase/tumor necrosis factor-α/nuclear factor-κB/interleukin-1β/matrix metalloproteinase-9/plasminogen activator inhibitor-1/RANTES), oxidative-stress (NOX-1/NOX-2/oxidized protein), apoptotic (caspase-3/ Poly-ADP-ribose polymerase), and fibrotic (Smad3/transforming growth factor-β) biomarkers, and cellular expressions of brain-damaged (γ-H2AX+/ XRCC1-CD90+/p53BP1-CD90+), inflammatory (CD11+/CD68+/glial fibrillary acid protein+) and brain-edema (aquaporin-4+) markers showed a similar pattern of BIZ among the groups (all n < 0.0001). In conclusion, xenogenic ADMSC/ADMSC-derived exosome therapy was safe and offered the additional benefit of reducing BIZ and improving neurological function in rat AIS. PMID:27793019

  2. The Chemistry of Coatings.

    ERIC Educational Resources Information Center

    Griffith, James R.

    1981-01-01

    The properties of natural and synthetic polymeric "coatings" are reviewed, including examples and uses of such coatings as cellulose nitrate lacquers (for automobile paints), polyethylene, and others. (JN)

  3. Interfacial bond strength of electrophoretically deposited hydroxyapatite coatings on metals.

    PubMed

    Wei, M; Ruys, A J; Swain, M V; Kim, S H; Milthorpe, B K; Sorrell, C C

    1999-07-01

    Hydroxyapatite (HAp) coatings were deposited onto substrates of metal biomaterials (Ti, Ti6Al4V, and 316L stainless steel) by electrophoretic deposition (EPD). Only ultra-high surface area HAp powder, prepared by the metathesis method 10Ca(NO3)2 + 6(NH4)2HPO4 + 8NH4OH), could produce dense coatings when sintered at 875-1000degreesC. Single EPD coatings cracked during sintering owing to the 15-18% sintering shrinkage, but the HAp did not decompose. The use of dual coatings (coat, sinter, coat, sinter) resolved the cracking problem. Scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) inspection revealed that the second coating filled in the "valleys" in the cracks of the first coating. The interfacial shear strength of the dual coatings was found, by ASTM F1044-87, to be approximately 12 MPa on a titanium substrate and approximately 22 MPa on 316L stainless steel, comparing quite favorably with the 34 MPa benchmark (the shear strength of bovine cortical bone was found to be 34 MPa). Stainless steel gave the better result since -316L (20.5 microm mK(-1)) > alpha-HAp (approximately 14 microm mK(-1)), resulting in residual compressive stresses in the coating, whereas alpha-titanium (approximately 10.3 microm mK(-1)) < alpha-HAp, resulting in residual tensile stresses in the coating.

  4. Developing bioactive composite scaffolds for bone tissue engineering

    NASA Astrophysics Data System (ADS)

    Chen, Yun

    Poly(L-lactic acid) (PLLA) films were fabricated using the method of dissolving and evaporation. PLLA scaffold was prepared by solid-liquid phase separation of polymer solutions and subsequent sublimation of solvent. Bonelike apatite coating was formed on PLLA films, PLLA scaffolds and poly(glycolic acid) (PGA) scaffolds in 24 hours through an accelerated biomimetic process. The ion concentrations in the simulated body fluid (SBF) were nearly 5 times of those in human blood plasma. The apatite formed was characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The apatite formed in 5SBF was similar in morphology and composition to that formed in the classical biomimetic process employing SBF or 1.5SBF, and similar to that of natural bone. This indicated that the biomimetic apatite coating process could be accelerated by using concentrated simulated body fluid at 37°C. Besides saving time, the accelerated biomimetic process is particularly significant to biodegradable polymers. Some polymers which degrade too fast to be coated with apatite by a classical biomimetic process, for example PGA, could be coated with bone-like apatite in an accelerated biomimetic process. Collagen and apatite were co-precipitated as a composite coating on poly(L-lactic acid) (PLLA) in an accelerated biomimetic process. The incubation solution contained collagen (1g/L) and simulated body fluid (SBF) with 5 times inorganic ionic concentrations as human blood plasma. The coating formed on PLLA films and scaffolds after 24 hours incubation was characterized using EDX, XRD, FTIR, and SEM. It was shown that the coating contained carbonated bone-like apatite and collagen, the primary constituents of natural bone. SEM showed a complex composite coating of submicron bone-like apatite particulates combined with collagen fibrils. This work provided an efficient process to obtain

  5. Magnesium-containing mixed coatings on zirconia for dental implants: mechanical characterization and in vitro behavior.

    PubMed

    Pardun, Karoline; Treccani, Laura; Volkmann, Eike; Streckbein, Philipp; Heiss, Christian; Gerlach, Juergen W; Maendl, Stephan; Rezwan, Kurosch

    2015-07-01

    An important challenge in the field of dental and orthopedic implantology is the preparation of implant coatings with bioactive functions that feature a high mechanical stability and at the same time mimic structural and compositional properties of native bone for a better bone ingrowth. This study investigates the influence of magnesium addition to zirconia-calcium phosphate coatings. The mixed coatings were prepared with varying additions of either magnesium oxide or magnesium fluoride to yttria-stabilized zirconia and hydroxyapatite. The coatings were deposited on zirconia discs and screw implants by wet powder spraying. Microstructure studies confirm a porous coating with similar roughness and firm adhesion not hampered by the coating composition. The coating morphology, mechanical flexural strength and calcium dissolution showed a magnesium content-dependent effect. Moreover, the in vitro results obtained with human osteoblasts reveal an improved biological performance caused by the presence of Mg(2+) ions. The magnesium-containing coatings exhibited better cell proliferation and differentiation in comparison to pure zirconia-calcium phosphate coatings. In conclusion, these results demonstrate that magnesium addition increases the bioactivity potential of zirconia-calcium phosphate coatings and is thus a highly suitable candidate for bone implant coatings.

  6. Poly(vinyl alcohol) hydrogel coatings with tunable surface exposure of hydroxyapatite.

    PubMed

    Moreau, David; Villain, Arthur; Ku, David N; Corté, Laurent

    2014-01-01

    Insufficient bone anchoring is a major limitation of artificial substitutes for connective osteoarticular tissues. The use of coatings containing osseoconductive ceramic particles is one of the actively explored strategies to improve osseointegration and strengthen the bone-implant interface for general tissue engineering. Our hypothesis is that hydroxyapatite (HA) particles can be coated robustly on specific assemblies of PVA hydrogel fibers for the potential anchoring of ligament replacements. A simple dip-coating method is described to produce composite coatings made of microscopic hydroxyapatite (HA) particles dispersed in a poly(vinyl alcohol) (PVA) matrix. The materials are compatible with the requirements for implant Good Manufacturing Practices. They are applied to coat bundles of PVA hydrogel fibers used for the development of ligament implants. By means of optical and electronic microscopy, we show that the coating thickness and surface state can be adjusted by varying the composition of the dipping solution. Quantitative analysis based on backscattered electron microscopy show that the exposure of HA at the coating surface can be tuned from 0 to over 55% by decreasing the weight ratio of PVA over HA from 0.4 to 0.1. Abrasion experiments simulating bone-implant contact illustrate how the coating cohesion and wear resistance increase by increasing the content of PVA relative to HA. Using pullout experiments, we find that these coatings adhere well to the fiber bundles and detach by propagation of a crack inside the coating. These results provide a guide to select coated implants for anchoring artificial ligaments.

  7. Specific Biomimetic Hydroxyapatite Nanotopographies Enhance Osteoblastic Differentiation and Bone Graft Osteointegration

    PubMed Central

    Loiselle, Alayna E.; Wei, Lai; Faryad, Muhammad; Paul, Emmanuel M.; Lewis, Gregory S.; Gao, Jun; Lakhtakia, Akhlesh

    2013-01-01

    Impaired healing of cortical bone grafts represents a significant clinical problem. Cadaveric bone grafts undergo extensive chemical processing to decrease the risk of disease transmission; however, these processing techniques alter the bone surface and decrease the osteogenic potential of cells at the healing site. Extensive work has been done to optimize the surface of bone grafts, and hydroxyapatite (HAP) and nanotopography both increase osteoblastic differentiation. HAP is the main mineral component of bone and can enhance osteoblastic differentiation and bone implant healing in vivo, while nanotopography can enhance osteoblastic differentiation, adhesion, and proliferation. This is the first study to test the combined effects of HAP and nanotopographies on bone graft healing. With the goal of identifying the optimized surface features to improve bone graft healing, we tested the hypothesis that HAP-based nanotopographic resurfacing of bone grafts improves integration of cortical bone grafts by enhancing osteoblastic differentiation. Here we show that osteoblastic cells cultured on processed bones coated with specific-scale (50–60 nm) HAP nanotopographies display increased osteoblastic differentiation compared to cells on uncoated bone, bones coated with poly-l-lactic acid nanotopographies, or other HAP nanotopographies. Further, bone grafts coated with 50–60-nm HAP exhibited increased formation of new bone and improved healing, with mechanical properties equivalent to live autografts. These data indicate the potential for specific HAP nanotopographies to not only increase osteoblastic differentiation but also improve bone graft incorporation, which could significantly increase patient quality of life after traumatic bone injuries or resection of an osteosarcoma. PMID:23510012

  8. Electrocurtain coating process for coating solar mirrors

    DOEpatents

    Kabagambe, Benjamin; Boyd, Donald W.; Buchanan, Michael J.; Kelly, Patrick; Kutilek, Luke A.; McCamy, James W.; McPheron, Douglas A.; Orosz, Gary R.; Limbacher, Raymond D.

    2013-10-15

    An electrically conductive protective coating or film is provided over the surface of a reflective coating of a solar mirror by flowing or directing a cation containing liquid and an anion containing liquid onto the conductive surface. The cation and the anion containing liquids are spaced from, and preferably out of contact with one another on the surface of the reflective coating as an electric current is moved through the anion containing liquid, the conductive surface between the liquids and the cation containing liquid to coat the conductive surface with the electrically conductive coating.

  9. Bone Density Test

    MedlinePlus

    Tests and Procedures Bone density test By Mayo Clinic Staff A bone density test determines if you have osteoporosis — a disease that causes bones to ... your bones could be quite weak. A bone density test enhances the accuracy of calculating your risk ...

  10. Proximal Tibial Bone Graft

    MedlinePlus

    ... All Site Content AOFAS / FootCareMD / Treatments Proximal Tibial Bone Graft Page Content What is a bone graft? Bone grafts may be needed for various ... the proximal tibia. What is a proximal tibial bone graft? Proximal tibial bone graft (PTBG) is a ...

  11. Improving gingival smile by means of guided bone regeneration principles

    PubMed Central

    Ferreira, Carlos Eduardo de Almeida; Brandão, Roberto Carlos Bodart; Martinelli, Carolina Borges; Pignaton, Túlio Bonna

    2016-01-01

    ABSTRACT Objective: This study evaluated the effectiveness of guided bone regeneration (GBR) carried out with xenogenic bone substitute (Bio-OssTM) and collagen resorbable membrane (Bio-GideTM) to improve gingival smile (GS) in patients with excessive vertical maxillary growth (EVMG). Methods: Twelve healthy women aged between 20 and 49 years old (mean age of 26 years), with 5 mm or more of gingival exposure during fully posed smile (FPS) due to EVMG, were included. Baseline digital photographs were taken with standardized head position at rest and FPS. In eight out of 12 cases, crown lengthening procedure was indicated and the initial incision was made 2 to 4 mm from the gingival margin. In four cases, with no indication for crown lengthening procedure, a sulcular incision was performed. GBR was performed in all cases, using micro screws and/or titanium mesh associated with Bio-OssTM and Bio-GideTM. After 10 days, sutures were removed. Recall appointments were scheduled at 1, 6, and 12 months when standardized photographs were again taken. ImageToolTM software was used to measure the gingival exposure (GE) during FPS from the standardized close-up smile photographs at baseline and 12 months. Results: GE mean at baseline was 275.44 mm2. After 12 months, patients who undergone exclusively GBR procedure, presented GE reduction of 40.7%, ∆ = 112.01 mm2 (statistically significant, p = 0.12), and patients who had crown lengthening associated with the graft had a reduction of 60%, ∆ = 167.01 mm2. Conclusion: Our results using GBR to improve GS in cases of EVMG showed an exceptionally high patient acceptance and satisfaction. One-year follow-up confirmed stable results. PMID:27409660

  12. Electrodeposited silk coatings for functionalized implant applications

    NASA Astrophysics Data System (ADS)

    Elia, Roberto

    modulated over a 10-fold range and implant insertion into bone mimics demonstrated that the coatings were able to withstand delamination forces experienced during these mock implantations. Antibiotic release from coated implant studs inhibited bacterial growth and dexamethasone release was shown to stimulate calcium deposition in mesenchymal stem cells.

  13. Bone scan in metabolic bone diseases. Review.

    PubMed

    Abdelrazek, Saeid; Szumowski, Piotr; Rogowski, Franciszek; Kociura-Sawicka, Agnieszka; Mojsak, Małgorzata; Szorc, Małgorzata

    2012-08-25

    Metabolic bone disease encompasses a number of disorders that tend to present a generalized involvement of the whole skeleton. The disorders are mostly related to increased bone turnover and increased uptake of radiolabelled diphosphonate. Skeletal uptake of 99mTc-labelled diphosphonate depends primarily upon osteoblastic activity, and to a lesser extent, skeletal vascularity. A bone scan image therefore presents a functional display of total skeletal metabolism and has valuable role to play in the assessment of patients with metabolic bone disorders. However, the bone scan appearances in metabolic bone disease are often non-specific, and their recognition depends on increased tracer uptake throughout the whole skeleton. It is the presence of local lesions, as in metastatic disease, that makes a bone scan appearance obviously abnormal. In the early stages, there will be difficulty in evaluating the bone scans from many patients with metabolic bone disease. However, in the more severe cases scan appearances can be quite striking and virtually diagnostic.

  14. Bioactive Coatings for Orthopaedic Implants—Recent Trends in Development of Implant Coatings

    PubMed Central

    Zhang, Bill G. X.; Myers, Damian E.; Wallace, Gordon G.; Brandt, Milan; Choong, Peter F. M.

    2014-01-01

    Joint replacement is a major orthopaedic procedure used to treat joint osteoarthritis. Aseptic loosening and infection are the two most significant causes of prosthetic implant failure. The ideal implant should be able to promote osteointegration, deter bacterial adhesion and minimize prosthetic infection. Recent developments in material science and cell biology have seen the development of new orthopaedic implant coatings to address these issues. Coatings consisting of bioceramics, extracellular matrix proteins, biological peptides or growth factors impart bioactivity and biocompatibility to the metallic surface of conventional orthopaedic prosthesis that promote bone ingrowth and differentiation of stem cells into osteoblasts leading to enhanced osteointegration of the implant. Furthermore, coatings such as silver, nitric oxide, antibiotics, antiseptics and antimicrobial peptides with anti-microbial properties have also been developed, which show promise in reducing bacterial adhesion and prosthetic infections. This review summarizes some of the recent developments in coatings for orthopaedic implants. PMID:25000263

  15. Bioactive coatings for orthopaedic implants-recent trends in development of implant coatings.

    PubMed

    Zhang, Bill G X; Myers, Damian E; Wallace, Gordon G; Brandt, Milan; Choong, Peter F M

    2014-07-04

    Joint replacement is a major orthopaedic procedure used to treat joint osteoarthritis. Aseptic loosening and infection are the two most significant causes of prosthetic implant failure. The ideal implant should be able to promote osteointegration, deter bacterial adhesion and minimize prosthetic infection. Recent developments in material science and cell biology have seen the development of new orthopaedic implant coatings to address these issues. Coatings consisting of bioceramics, extracellular matrix proteins, biological peptides or growth factors impart bioactivity and biocompatibility to the metallic surface of conventional orthopaedic prosthesis that promote bone ingrowth and differentiation of stem cells into osteoblasts leading to enhanced osteointegration of the implant. Furthermore, coatings such as silver, nitric oxide, antibiotics, antiseptics and antimicrobial peptides with anti-microbial properties have also been developed, which show promise in reducing bacterial adhesion and prosthetic infections. This review summarizes some of the recent developments in coatings for orthopaedic implants.

  16. Bone scan appearances following bone and bone marrow biopsy

    SciTech Connect

    McKillop, J.H.; Maharaj, D.; Boyce, B.F.; Fogelman, I.

    1984-01-01

    Bone marrow and bone biopsies are performed not infrequently in patients referred for bone scans and represent a potential cause of a ''false positive'' focal abnormality on the bone scan. The authors have therefore examined the scan appearances in a series of patients who had undergone either sternal marrow biopsy, (Salah needle, diameter 1.2 mm) trephine iliac crest marrow biopsy (Jamshidi 11 gauge needle, diameter 3.5 mm) or a transiliac bone biopsy (needle diameter 8 mm). Of 18 patients studied 1 to 45 days after sternal marrow 17 had normal scan appearances at the biopsy site and 1 had a possible abnormality. None of 9 patients studied 4 to 19 days after trephine iliac crest marrow biopsy had a hot spot at the biopsy site. A focal scan abnormality was present at the biopsy site in 9/11 patients studied 5 to 59 days after a trans iliac bone biopsy. No resultant scan abnormality was seen in 4 patients imaged within 3 days of the bone biopsy or in 3 patients imaged 79 to 138 days after the procedure. Bone marrow biopsy of the sternum or iliac crest does not usually cause bone scan abnormalities. A focal abnormality at the biopsy site is common in patients imaged 5 days to 2 months after bone biopsy. The gauge of the needle employed in the biopsy and thus the degree of bone trauma inflicted, is likely to be main factor determining the appearance of bone scan abnormalities at the biopsy site.

  17. Composites structures for bone tissue reconstruction

    NASA Astrophysics Data System (ADS)

    Neto, W.; Santos, João.; Avérous, L.; Schlatter, G.; Bretas, Rosario.

    2015-05-01

    The search for new biomaterials in the bone reconstitution field is growing continuously as humane life expectation and bone fractures increase. For this purpose, composite materials with biodegradable polymers and hydroxyapatite (HA) have been used. A composite material formed by a film, nanofibers and HA has been made. Both, the films and the non-woven mats of nanofibers were formed by nanocomposites made of butylene adipate-co-terephthalate (PBAT) and HA. The techniques used to produce the films and nanofibers were spin coating and electrospinning, respectively. The composite production and morphology were evaluated. The composite showed an adequate morphology and fibers size to be used as scaffold for cell growth.

  18. Composites structures for bone tissue reconstruction

    SciTech Connect

    Neto, W.; Santos, João; Avérous, L.; Schlatter, G.; Bretas, Rosario

    2015-05-22

    The search for new biomaterials in the bone reconstitution field is growing continuously as humane life expectation and bone fractures increase. For this purpose, composite materials with biodegradable polymers and hydroxyapatite (HA) have been used. A composite material formed by a film, nanofibers and HA has been made. Both, the films and the non-woven mats of nanofibers were formed by nanocomposites made of butylene adipate-co-terephthalate (PBAT) and HA. The techniques used to produce the films and nanofibers were spin coating and electrospinning, respectively. The composite production and morphology were evaluated. The composite showed an adequate morphology and fibers size to be used as scaffold for cell growth.

  19. Bone development

    PubMed Central

    Berendsen, Agnes D.; Olsen, Bjorn R.

    2015-01-01

    The development of the vertebrate skeleton reflects its evolutionary history. Cartilage formation came before biomineralization and a head skeleton evolved before the formation of axial and appendicular skeletal structures. This review describes the processes that result in endochondral and intramembranous ossification, the important roles of growth and transcription factors, and the consequences of mutations in some of the genes involved. Following a summary of the origin of cartilage, muscle, and tendon cell lineages in the axial skeleton, we discuss the role of muscle forces in the formation of skeletal architecture and assembly of musculoskeletal functional units. Finally, ontogenetic patterning of bones in response to mechanical loading is reviewed. PMID:26453494

  20. Multi-layer coatings

    DOEpatents

    Maghsoodi, Sina; Brophy, Brenor L.; Abrams, Ze'ev R.; Gonsalves, Peter R.

    2016-06-28

    Disclosed herein are coating materials and methods for applying a top-layer coating that is durable, abrasion resistant, highly transparent, hydrophobic, low-friction, moisture-sealing, anti-soiling, and self-cleaning to an existing conventional high temperature anti-reflective coating. The top coat imparts superior durability performance and new properties to the under-laying conventional high temperature anti-reflective coating without reducing the anti-reflectiveness of the coating. Methods and data for optimizing the relative thickness of the under-layer high temperature anti-reflective coating and the top-layer thickness for optimizing optical performance are also disclosed.

  1. Engineered PlyCB as a Novel Implant Coating for Osseointegration

    DTIC Science & Technology

    2012-03-01

    The lack of osseointegration is the primary cause of implant failure or shortened lifespan under physiological loads. Coatings such as hydroxyapatite ...the mineral component of bone, are often used to promote integration of bone with implant. However, hydroxyapatite coatings do not contain any...protein, was found to have a particularly high affinity for hydroxyapatite (Nelson, 2006). Based on the crystal structure, we plan to introduce mutants

  2. Menopause and Bone Loss

    MedlinePlus

    ... You reach your highest bone mass (size and density) at about age 30. Then, sometime between age ... your bones, your doctor may do a bone density test (DEXA scan). This test gives exact measurements ...

  3. Bone density scan (image)

    MedlinePlus

    ... bone the higher the risk of fractures. A bone scan, along with a patient's medical history, is a ... and whether any preventative treatment is needed. A bone density scan has the advantage of being painless and exposing ...

  4. Preparation and characterization of RF magnetron sputtered calcium pyrophosphate coatings.

    PubMed

    Yonggang, Yan; Wolke, J G C; Yubao, Li; Jansen, J A

    2006-03-15

    CaP ceramic has been widely used as coating on metals in orthopedics and oral dentistry. Variations in CaP composition can lead to different dissolution/precipitation behavior and may also affect the bone response. In the present study calcium pyrophosphate and hydroxylapatite coatings were successfully prepared by RF magnetron sputtering deposition. The phase composition, morphological properties, and the dissolution in SBF were characterized by using XRD, FTIR, EDS, SEM, and spectrophotometry. The results showed that all the sputtered coatings were amorphous and changed into a crystal structure after IR-radiation. The temperature for the crystallization of the amorphous coatings is lower for the hydroxylapatite coating (550 degrees C), compared to the calcium pyrophosphate coating (650 degrees C). All sputtered amorphous coatings were instable in SBF and dissolved partially within 4 wks of incubation. The heat-treated coatings appeared to be stable after incubation. These results showed that magnetron sputtering of calcium pyrophosphate coating is a promising method for forming a biocompatible ceramic coating.

  5. Dietary restrictions, bone density, and bone quality.

    PubMed

    Huang, Tsang-hai; Ables, Gene P

    2016-01-01

    Caloric restriction (CR), protein restriction (PR), and specific amino acid restriction (e.g., methionine restriction (MR)) are different dietary interventions that have been confirmed with regard to their comprehensive benefits to metabolism and health. Based on bone densitometric measurements, weight loss induced by dietary restriction is known to be accompanied by reduced areal bone mineral density, bone mass, and/or bone size, and it is considered harmful to bone health. However, because of technological advancements in bone densitometric instruments (e.g., high-resolution X-ray tomography), dietary restrictions have been found to cause a reduction in bone mass/size rather than volumetric bone mineral density. Furthermore, when considering bone quality, bone health consists of diverse indices that cannot be fully represented by densitometric measurements alone. Indeed, there is evidence that moderate dietary restrictions do not impair intrinsic bone material properties, despite the reduction in whole-bone strength because of a smaller bone size. In the present review, we integrate research evidence from traditional densitometric measurements, metabolic status assays (e.g., energy metabolism, oxidative stresses, and inflammatory responses), and biomaterial analyses to provide revised conclusions regarding the effects of CR, PR, and MR on the skeleton.

  6. Osteogenicity of titanium implants coated with calcium phosphate or collagen type-I in osteoporotic rats.

    PubMed

    Alghamdi, Hamdan S; Bosco, Ruggero; van den Beucken, Jeroen J J P; Walboomers, X Frank; Jansen, John A

    2013-05-01

    This study hypothesized that modification of titanium implant surface, e.g. by the deposition of inorganic/organic coatings, can significantly improve the implant-bone response compared in osteoporotic vs. healthy conditions. After osteoporosis was induced in 15 female Wistar rats by ovariectomy (OVX) and confirmed by in vivo micro-CT analysis, implants coated with calcium phosphate (CaP) or collagen type-I and non-coated implants were placed into bilateral femoral condyles. Another 15 sham-operated rats served as controls. Twelve weeks after implantation, micro-CT bone volume (%BV) and histomorphometrical bone area (%BA) were lower around control implants in osteoporotic rats (BV = 60.4%, BA = 43.8%) compared to sham-operated rats (BV = 74.0%, BA = 62.0%). Interestingly, CaP and collagen type-I surface coatings enhanced bone-to-implant contact (%BIC) compared to non-coated implants in osteoporosis (51.9%, 58.2%) as well as in sham-operated (69.7%, 64.4%) groups. The study confirmed that an osteoporotic condition has a significant effect on the amount of bone present in close vicinity to implants. Evidently, the use of osteogenic surface coatings has a favorable effect on the bone implant interface in both osteoporotic and sham-operated conditions.

  7. Transformation of nacre coatings into apatite coatings in phosphate buffer solution at low temperature.

    PubMed

    Guo, Yaping; Zhou, Yu

    2008-08-01

    Nacre coatings were deposited on Ti6Al4V substrates by electrophoretic technique, and subsequently converted into apatite coatings with hierarchical porous structures by treatment with a phosphate buffer solution. The samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, inductively coupled plasma optical emission spectroscopy, X-ray photoelectron spectroscopy (XPS), and N(2) adsorption-desorption isotherms. The results show that the nacre coatings are converted into the plate-like apatite coatings via a dissolution-precipitation reaction, while the organic components of the nacre are reserved. The mesopores with pore size of 4.4 nm are formed within the plate-like structure, and the macropores are formed among the plate-like structure. Simulated body fluid (SBF) immersion tests reveal that the apatite coatings have a good in vitro bioactivity. Bone-like apatite crystals are formed on the surfaces of the apatite coatings after soaking in SBF for 12 h, and fill up the macropores on the coatings with increasing the soaking time. In addition, XPS indicates that a TiO(x) layer and PO(4) (3-) ions appear on the substrate surfaces by pretreatment with a H(3)PO(4)/HF solution. The TiO(x) layer and PO(4) (3-) ions can induce the formation of apatite crystals, resulting in a composition gradient from the oxide layer to the external apatite layer.

  8. Bone marrow transplant - discharge

    MedlinePlus

    Transplant - bone marrow - discharge; Stem cell transplant - discharge; Hematopoietic stem cell transplant - discharge; Reduced intensity; Non-myeloablative transplant - discharge; Mini transplant - discharge; Allogenic bone marrow transplant - ...

  9. Randomized controlled clinical trial of 2 types of hydroxyapatite-coated implants on moderate periodontitis patients

    PubMed Central

    2016-01-01

    Purpose The aim of this study was to compare and analyze the peri-implant tissue conditions and prospective clinical outcomes associated with 2 types of hydroxyapatite (HA)-coated implants: (1) fully HA-coated implants and (2) partially HA-coated implants with resorbable blast medium on the coronal portion of the threads. Methods Forty-four partially edentulous patients were randomly assigned to undergo the placement of 62 HA-coated implants, and were classified as the control group (partially HA-coated, n=30) and the test group (fully HA-coated, n=32). All patients had chronic periodontitis with moderate crestal bone loss around the edentulous area. The stability and clinical outcomes of the implants were evaluated using the primary and secondary implant stability quotient (ISQ), as well as radiographic, mobility, and peri-implant soft tissue assessments around the implants. The Wilcoxon signed-rank test and the Mann-Whitney test were used to evaluate differences between and within the 2 groups, with P values <0.05 considered to indicate statistical significance. Results The fully HA-coated implants displayed good retention of crestal bone, and insignificant differences were found in annual marginal bone loss between the 2 types of HA-coated implants (P>0.05). No significant differences were found in the survival rate (group I, 100%; group II, 100%) or the success rate (group I, 93.3%; group II, 93.8%). The fully HA-coated implants also did not significantly increase the risk of peri-implantitis (P>0.05). Conclusions The fully HA-coated implants did not lead to an increased risk of peri-implantitis and showed good retention of the crestal bone, as well as good survival and success rates. Our study suggests that fully HA-coated implants could become a reliable treatment alternative for edentulous posterior sites and are capable of providing good retention of the crestal bone. PMID:27800216

  10. Flow coating apparatus and method of coating

    SciTech Connect

    Hanumanthu, Ramasubrahmaniam; Neyman, Patrick; MacDonald, Niles; Brophy, Brenor; Kopczynski, Kevin; Nair, Wood

    2014-03-11

    Disclosed is a flow coating apparatus, comprising a slot that can dispense a coating material in an approximately uniform manner along a distribution blade that increases uniformity by means of surface tension and transfers the uniform flow of coating material onto an inclined substrate such as for example glass, solar panels, windows or part of an electronic display. Also disclosed is a method of flow coating a substrate using the apparatus such that the substrate is positioned correctly relative to the distribution blade, a pre-wetting step is completed where both the blade and substrate are completed wetted with a pre-wet solution prior to dispensing of the coating material onto the distribution blade from the slot and hence onto the substrate. Thereafter the substrate is removed from the distribution blade and allowed to dry, thereby forming a coating.

  11. Influence of Starting Powders on Hydroxyapatite Coatings Fabricated by Room Temperature Spraying Method.

    PubMed

    Seo, Dong Seok; Lee, Jong Kook; Hwang, Kyu Hong; Hahn, Byung Dong; Yoon, Seog Young

    2015-08-01

    Three types of raw materials were used for the fabrication of hydroxyapatite coatings by using the room temperature spraying method and their influence on the microstructure and in vitro characteristics were investigated. Starting hydroxyapatite powders for coatings on titanium substrate were prepared by a heat treatment at 1100 °C for 2 h of bovine bone, bone ash, and commercial hydroxyapatite powders. The phase compositions and Ca/P ratios of the three hydroxyapatite coatings were similar to those of the raw materials without decomposition or formation of a new phase. All hydroxyapatite coatings showed a honeycomb structure, but their surface microstructures revealed different features in regards to surface morphology and roughness, based on the staring materials. All coatings consisted of nano-sized grains and had dense microstructure. Inferred from in vitro experiments in pure water, all coatings have a good dissolution-resistance and biostability in water.

  12. Microstructure and osteoblast response of gradient bioceramic coating on titanium alloy fabricated by laser cladding

    NASA Astrophysics Data System (ADS)

    Zheng, Min; Fan, Ding; Li, Xiu-Kun; Li, Wen-Fei; Liu, Qi-Bin; Zhang, Jian-Bin

    2008-11-01

    To construct a bioactive interface between metal implant and the surrounding bone tissue, the gradient calcium phosphate bioceramic coating on titanium alloy (Ti-6Al-4V) was designed and fabricated by laser cladding. The results demonstrated that the gradient bioceramic coating was metallurgically bonded to the titanium alloy substrate. The appearance of hydroxyapatite and β-tricalcium phosphate indicated that the bioactive phases were synthesized on the surface of coating. The microhardness gradually decreased from the coating to substrate, which could help stress relaxation between coating and bone tissue. Furthermore, the methyl thiazolyl tetrazolium (MTT) assay of cell proliferation revealed that the laser-cladded bioceramic coating had more favorable osteoblast response compared with the surface of untreated titanium alloy substrate.

  13. Apparatus for coating powders

    DOEpatents

    Makowiecki, Daniel M.; Kerns, John A.; Alford, Craig S.; McKernan, Mark A.

    2000-01-01

    A process and apparatus for coating small particles and fibers. The process involves agitation by vibrating or tumbling the particles or fibers to promote coating uniformly, removing adsorbed gases and static charges from the particles or fibers by an initial plasma cleaning, and coating the particles or fibers with one or more coatings, a first coating being an adhesion coating, and with subsequent coatings being deposited in-situ to prevent contamination at layer interfaces. The first coating is of an adhesion forming element (i.e. W, Zr, Re, Cr, Ti) of a 100-10,000 .ANG. thickness and the second coating or final coating of a multiple (0.1-10 microns) being Cu or Ag, for example for brazing processes, or other desired materials that defines the new surface related properties of the particles. An essential feature of the coating process is the capability to deposit in-situ without interruption to prevent the formation of a contaminated interface that could adversely affect the coating adhesion. The process may include screening of the material to be coated and either continuous or intermittent vibration to prevent agglomeration of the material to be coated.

  14. Factors affecting bone growth.

    PubMed

    Gkiatas, Ioannis; Lykissas, Marios; Kostas-Agnantis, Ioannis; Korompilias, Anastasios; Batistatou, Anna; Beris, Alexandros

    2015-02-01

    Bone growth and development are products of the complex interactions of genetic and environmental factors. Longitudinal bone growth depends on the growth plate. The growth plate has 5 different zones-each with a different functional role-and is the final target organ for longitudinal growth. Bone length is affected by several systemic, local, and mechanical factors. All these regulation systems control the final length of bones in a complicated way. Despite its significance to bone stability, bone growth in width has not been studied as extensively as longitudinal bone growth. Bone growth in width is also controlled by genetic factors, but mechanical loading regulates periosteal apposition. In this article, we review the most recent data regarding bone growth from the embryonic age and analyze the factors that control bone growth. An understanding of this complex system is important in identifying metabolic and developmental bone diseases and fracture risk.

  15. Changes in physicochemical and biological properties of porcine bone derived hydroxyapatite induced by the incorporation of fluoride

    PubMed Central

    Qiao, Wei; Liu, Quan; Li, Zhipeng; Zhang, Hanqing; Chen, Zhuofan

    2017-01-01

    Abstract As the main inorganic component of xenogenic bone graft material, bone-derived biological apatite (BAp) has been widely used in implant dentistry, oral and maxillofacial surgery and orthopedics. However, BAp produced via calcination of animal bones still suffers from some drawbacks, such as insufficient mechanical strength and inadequate degradation rate, which impede its application. Fluoride is known to play important roles in both physiological and pathological processes of human hard tissues for its double effects on bones and teeth. In order to understand the effects of fluoride on the properties of BAp, as well as the mechanism behind them, porcine bone derived hydroxyapatite (PHAp) was prepared via thermal treatment, which was then fluoride incorporated at a series concentrations of sodium fluoride, and noted as 0.25-FPHAp, 0.50-FPHAp, and 0.75-FPHAp respectively. The physicochemical characteristics of the materials, including crystal morphology, crystallinity, functional groups, elemental composition, compressive strength, porosity and solubility, were then determined. The biological properties, such as protein adsorption and cell attachment, were also evaluated. It was found that the spheroid-like crystals of PHAp were changed into rod-like after fluoride substitution, resulting in a fluoride concentration-dependent increase in compressive strength, as well as a decreased porosity and solubility of the apatite. However, even though the addition of fluoride was demonstrated to enhance protein adsorption and cell attachment of the materials, the most favorable results were intriguingly achieved in FPHAp with the least fluoride content. Collectively, low level of fluoride incorporation is proposed promising for the modification of clinically used BAp based bone substitute materials, because of its being able to maintain a good balance between physicochemical and biological properties of the apatite. PMID:28243337

  16. The effect of hydroxyapatite nanocrystals on early bone formation surrounding dental implants.

    PubMed

    Svanborg, L M; Hoffman, M; Andersson, M; Currie, F; Kjellin, P; Wennerberg, A

    2011-03-01

    The knowledge of how nanostructures might affect early bone healing and osseointegration is limited. The aim of this study was to investigate if nanometer thick coatings of hydroxyapatite nanocrystals applied on a moderately rough surface might enhance early bone healing on screw-shaped dental implants and to evaluate if the thickness of the coat influences healing. Sandblasted and acid etched titanium implants coated with two different thicknesses of hydroxyapatite (test implants) and sandblasted and acid etched titanium implants (control implants), were inserted in rabbit tibia. After a healing time of 2, 4 and 9 weeks, a removal torque analysis and a histological evaluation were performed. The results from the removal torque analysis showed a tendency for higher values for the double coated hydroxyapatite after 4 weeks and for both the coated surfaces after 9 weeks of healing. The histological evaluations indicated slightly more new bone formation with the coated implants compared with the control; the differences did not reach statistical significance. The present study could not support the importance of nanometer thick coatings of hydroxyapatite nanocrystals in early bone healing, at least not when applied on a blasted and etched surface and placed in a cortical bone.

  17. Bioactivity of calcium phosphate bioceramic coating fabricated by laser cladding

    NASA Astrophysics Data System (ADS)

    Zhu, Yizhi; Liu, Qibin; Xu, Peng; Li, Long; Jiang, Haibing; Bai, Yang

    2016-05-01

    There were always strong expectations for suitable biomaterials used for bone regeneration. In this study, to improve the biocompatiblity of titanium alloy, calcium phosphate bioceramic coating was obtained by laser cladding technology. The microstructure, phases, bioactivity, cell differentiation, morphology and resorption lacunae were investigated by optical microscope (OM), x-ray diffraction (XRD), methyl thiazolyl tetrazolium (MTT) assay, tartrate-resistant acid phosphatase (TRAP) staining and scanning electronic microscope (SEM), respectively. The results show that bioceramic coating consists of three layers, which are a substrate, an alloyed layer and a ceramic layer. Bioactive phases of β-tricalcium phosphate (β-TCP) and hydroxyapatite (HA) were found in ceramic coating. Osteoclast precursors have excellent proliferation on the bioceramic surface. The bioceramics coating could be digested by osteoclasts, which led to the resorption lacunae formed on its surface. It revealed that the gradient bioceramic coating has an excellent bioactivity.

  18. Hybrid calcium phosphate coatings for implants

    NASA Astrophysics Data System (ADS)

    Malchikhina, Alena I.; Shesterikov, Evgeny V.; Bolbasov, Evgeny N.; Ignatov, Viktor P.; Tverdokhlebov, Sergei I.

    2016-08-01

    Monophasic biomaterials cannot provide all the necessary functions of bones or other calcined tissues. It is necessary to create for cancer patients the multiphase materials with the structure and composition simulating the natural bone. Such materials are classified as hybrid, obtained by a combination of chemically different components. The paper presents the physical, chemical and biological studies of coatings produced by hybrid technologies (HT), which combine primer layer and calcium phosphate (CaP) coating. The first HT type combines the method of vacuum arc titanium primer layer deposition on a stainless steel substrate with the following micro-arc oxidation (MAO) in phosphoric acid solution with addition of calcium compounds to achieve high supersaturated state. MAO CaP coatings feature high porosity (2-8%, pore size 5-7 µm) and surface morphology with the thickness greater than 5 µm. The thickness of Ti primer layer is 5-40 µm. Amorphous MAO CaP coating micro-hardness was measured at maximum normal load Fmax = 300 mN. It was 3.1 ± 0.8 GPa, surface layer elasticity modulus E = 110 ± 20 GPa, roughness Ra = 0.9 ± 0.1 µm, Rz = 7.5 ± 0.2 µm, which is less than the titanium primer layer roughness. Hybrid MAO CaP coating is biocompatible, able to form calcium phosphates from supersaturated body fluid (SBF) solution and also stimulates osteoinduction processes. The second HT type includes the oxide layer formation by thermal oxidation and then CaP target radio frequency magnetron sputtering (RFMS). Oxide-RFMS CaP coating is a thin dense coating with good adhesion to the substrate material, which can be used for metal implants. The RFMS CaP coating has thickness 1.6 ± 0.1 µm and consists of main target elements calcium and phosphorus and Ca/P ratio 2.4. The second HT type can form calcium phosphates from SBF solution. In vivo study shows that hybrid RFMS CaP coating is biocompatible and produces fibrointegration processes.

  19. Bone scan appearances following biopsy of bone and bone marrow

    SciTech Connect

    McKillop, J.H.; Maharaj, D.; Boyce, B.F.; Fogelman, I.

    1984-10-01

    The influence of sternal marrow aspiration, iliac crest marrow aspiration, and iliac crest bone biopsy on bone scan appearances was examined. Eighteen patients were scanned a mean of 9.9 days after sternal marrow aspiration with a Salah needle. Bone scans obtained in 9 patients a mean of 10 days aftr iliac crest trephine marrow biopsy with a Jamshidi needle showed no abnormality at the biopsy site. In 18 patients with metabolic bone disease who had undergone iliac crest bone biopsy with an 8 mm needle, a scan abnormality due to the biopsy was usually present when the interval between the biopsy and the scan was 5 days to 2 months. Patients who were scanned within 3 days of iliac crest bone biopsy or more than 2 months after biopsy had normal scan appearance at the biopsy site.

  20. Laser processing of bioactive tricalcium phosphate coating on titanium for load-bearing implants.

    PubMed

    Roy, Mangal; Vamsi Krishna, B; Bandyopadhyay, Amit; Bose, Susmita

    2008-03-01

    Laser-engineered net shaping (LENS), a commercial rapid prototyping (RP) process, was used to coat titanium with tricalcium phosphate (TCP) ceramics to improve bone cell-materials interactions. During LENS coating process, the Nd:YAG laser melts the top surface of Ti substrate in which calcium phosphate powder is fed to create a TCP-Ti composite layer. It was found that an increase in laser power and/or powder feed rate increases the thickness of the coating. However, coating thickness decreased with increasing laser scan speed. TCP coating showed columnar titanium grains at the substrate side of the coating and transitioned to equiaxed titanium grains at the outside. When the scan speed was reduced from 15 to 10mms(-1), coating hardness increased from 882+/-67 to 1049+/-112Hv due to an increase in the volume fraction of TCP in the coating. Coated surfaces showed uniformly distributed TCP particles and X-ray diffraction data confirmed the absence of any undesirable phases, while maintaining a high level of crystallinity. The effect of TCP coating on cell-material interaction was examined by culturing osteoprecursor cells (OPC1) on coated surfaces. The results indicated that TCP coating had good biocompatibility where OPC1 cells attached and proliferated on the coating surface. The coating also initiated cell differentiation, ECM formation and biomineralization.

  1. Bone Marrow Diseases

    MedlinePlus

    Bone marrow is the spongy tissue inside some of your bones, such as your hip and thigh bones. It contains stem cells. The stem cells can ... the platelets that help with blood clotting. With bone marrow disease, there are problems with the stem ...

  2. Metastatic Bone Disease

    MedlinePlus

    ... secrete factors that interact with the naturally occurring cells in the bone and cause bone destruction, new bone formation, or both. Effects Because MBD weakens the affected bones, people with the disease are prone to fractures. Broken ...

  3. New operational techniques of implantation of biomaterials and titanium implants in the jaw with the atrophy of the bone and soft tissues

    NASA Astrophysics Data System (ADS)

    Nikityuk, D. B.; Urakov, A. L.; Reshetnikov, A. P.; Kopylov, M. V.; Baimurzin, D. Yu.

    2015-11-01

    The research into dynamics of quality of clinical use in 2003 - 2012 of autologous and xenogeneic biomaterials at dental transplantation and implantation among 1,100 of adult patients was made. The analysis results show that at autologous bone transplantation implant survival is observed only in 72% of cases, and the "necessary" result of bone repair occurred only in 6 - 9 months. Transplantation of biomaterials of OsteoBiol® (materials "mp3", "Genos" and "Evolution") provided engraftment and bone regeneration in 100 % of cases and allowed the use of dental implantation immediately after transplantation even in case of reduction in the patient's alveolar crest down to 2.0 mm. Replace Select implants of Nobel Biocare® were used at plantation. In order to exclude Schneiderian membrane's perforation lighting of Highmore's sinus with the cold blue-violet light from inside at sinus elevation is recommended as well as deepening of dental instruments into the bone only until the blue-violet light appears under them. To exclude deficiency of soft tissue under the cervical part of the ceramic crown application of special anti-fissure technology involving biomaterial flap dissection and its laying around the implant is suggested.

  4. Water-mediated structuring of bone apatite.

    PubMed

    Wang, Yan; Von Euw, Stanislas; Fernandes, Francisco M; Cassaignon, Sophie; Selmane, Mohamed; Laurent, Guillaume; Pehau-Arnaudet, Gérard; Coelho, Cristina; Bonhomme-Coury, Laure; Giraud-Guille, Marie-Madeleine; Babonneau, Florence; Azaïs, Thierry; Nassif, Nadine

    2013-12-01

    It is well known that organic molecules from the vertebrate extracellular matrix of calcifying tissues are essential in structuring the apatite mineral. Here, we show that water also plays a structuring role. By using solid-state nuclear magnetic resonance, wide-angle X-ray scattering and cryogenic transmission electron microscopy to characterize the structure and organization of crystalline and biomimetic apatite nanoparticles as well as intact bone samples, we demonstrate that water orients apatite crystals through an amorphous calcium phosphate-like layer that coats the crystalline core of bone apatite. This disordered layer is reminiscent of those found around the crystalline core of calcified biominerals in various natural composite materials in vivo. This work provides an extended local model of bone biomineralization.

  5. Transcutaneous Raman Spectroscopy of Murine Bone In Vivo

    PubMed Central

    Schulmerich, Matthew V.; Cole, Jacqueline H.; Kreider, Jaclynn M.; Esmonde-White, Francis; Dooley, Kathryn A.; Goldstein, Steven A.; Morris, Michael D.

    2009-01-01

    Raman spectroscopy can provide valuable information about bone tissue composition in studies of bone development, biomechanics, and health. In order to study the Raman spectra of bone in vivo, instrumentation that enhances the recovery of subsurface spectra must be developed and validated. Five fiber-optic probe configurations were considered for transcutaneous bone Raman spectroscopy of small animals. Measurements were obtained from the tibia of sacrificed mice, and the bone Raman signal was recovered for each probe configuration. The configuration with the optimal combination of bone signal intensity, signal variance, and power distribution was then evaluated under in vivo conditions. Multiple in vivo transcutaneous measurements were obtained from the left tibia of 32 anesthetized mice. After collecting the transcutaneous Raman signal, exposed bone measurements were collected and used as a validation reference. Multivariate analysis was used to recover bone spectra from transcutaneous measurements. To assess the validity of the transcutaneous bone measurements cross-correlations were calculated between standardized spectra from the recovered bone signal and the exposed bone measurements. Additionally, the carbonate-to-phosphate height ratios of the recovered bone signals were compared to the reference exposed bone measurements. The mean cross-correlation coefficient between the recovered and exposed measurements was 0.96, and the carbonate-to-phosphate ratios did not differ significantly between the two sets of spectra (p > 0.05). During these first systematic in vivo Raman measurements, we discovered that probe alignment and animal coat color influenced the results and thus should be considered in future probe and study designs. Nevertheless, our noninvasive Raman spectroscopic probe accurately assessed bone tissue composition through the skin in live mice. PMID:19281644

  6. Osteoblast precursor cell attachment on heat-treated calcium phosphate coatings.

    PubMed

    Yang, Y; Bumgardner, J D; Cavin, R; Carnes, D L; Ong, J L

    2003-06-01

    The influence of properties of calcium phosphate (CaP) coatings on bone cell activity and bone-implant osseointegration is not well-established. This study investigated the effects of characterized CaP coatings of various heat treatments on osteoblast response. It was hypothesized that heat treatments of CaP coatings alter the initial osteoblast attachment. The 400 degrees C heat-treated coatings were observed to exhibit poor crystallinity and significantly greater phosphate or apatite species compared with as-sputtered and 600 degrees C heat-treated coatings. Similarly, human embryonic palatal mesenchyme (HEPM) cells, an osteoblast precursor cell line, seeded on 400 degrees C heat-treated coatings, exhibited significantly greater cell attachment compared with Ti surfaces, as-sputtered coatings, and 600 degrees C heat-treated coatings. The HEPM cells on Ti surfaces and heat-treated coatings were observed to attach through filopodia, and underwent cell division, whereas the cells on as-sputtered coatings displayed fewer filopodia extensions and cell damage. Analysis of the data suggested that heat treatment of CaP coatings affects cell attachment.

  7. Bioactive composite gradient coatings of nano-hydroxyapatite/polyamide66 fabricated on polyamide66 substrates

    PubMed Central

    Huang, Di; Zuo, Yi; Li, Jidong; Zou, Qin; Zhang, Li; Gong, Mei; Wang, Li; Li, Limei; Li, Yubao

    2012-01-01

    Tightly bonding of bioactive coating is the first crucial need for orthopaedic implants. This study describes a novel and convenient technique to prepare bioactive coating with high adhesion on orthopaedic substitutes made of polymeric matrix. Here, a chemical corrosion method has been adopted to fabricate a coating on the surface of injection-moulded polyamide66 (PA66) substrates by corrosive nano-hydroxyapatite/polyamide66 (n-HA/PA66) composite slurry. Scanning electron microscopy observation shows that a porous chemical corrosion region presents between the coating and dense PA66 substrate. Energy-dispersive X-ray spectroscopy analysis indicates that the chemical corrosion region is mainly composed of PA66 matrix, and the coating layer is an n-HA-rich layer. Both the pore size and n-HA composition increase gradually from the polymeric substrate towards the coating surface. Mechanical testing shows the bonding strength can reach 13.7 ± 0.2 MPa, which is much higher than that fabricated on polymeric matrix by other coating methods. The gradual transition in coating structure and composition benefits for the interface bonding and for the surface bone-bonding bioactivity. Subsequent cell experiments corroborate n-HA-rich coating and a porous structure is benefitting for cell attachment and proliferation. The convenient coating method could be popularized and applied on similar polymer implants to produce a tightly and porous bioactive coating for bone tissue regeneration. PMID:22258549

  8. Bone Health and Osteoporosis.

    PubMed

    Lupsa, Beatrice C; Insogna, Karl

    2015-09-01

    Osteoporosis is characterized by low bone mass and microarchitectural deterioration of bone tissue leading to decreased bone strength and an increased risk of low-energy fractures. Central dual-energy X-ray absorptiometry measurements are the gold standard for determining bone mineral density. Bone loss is an inevitable consequence of the decrease in estrogen levels during and following menopause, but additional risk factors for bone loss can also contribute to osteoporosis in older women. A well-balanced diet, exercise, and smoking cessation are key to maintaining bone health as women age. Pharmacologic agents should be recommended in patients at high risk for fracture.

  9. [Imaging of bone metastases].

    PubMed

    Amoretti, Nicolas; Thariat, Juliette; Nouri, Yasir; Foti, Pauline; Hericord, Olivier; Stolear, Sandy; Coco, Lucia; Hauger, Olivier; Huwart, Laurent; Boileau, Pascal

    2013-11-01

    Bone metastases are detected at initial diagnosis of cancer in 25% of cases and bone metastases are common in the course of a majority of cancer types. The spine and proximal long bones are the most affected sites. Knowledge of the basic radiological semiology is important to make the proper diagnosis of metastasis(s) bone(s), especially in situations in which the clinical context is not suggestive of metastases (such as cases where bone metastases are inaugural or cases of peripheral solitary metastasis). Tumor aggressiveness can be assessed at the level of the cortical bone and periosteum. Lodwick criteria are useful for the diagnosis of malignancy and tumor aggressiveness at initial diagnosis on plain radiographs, which are very important in the context of bone metastases. A CT scanner is required to confirm the malignancy of a bone lesion. MRI is complementary to the scanner including for the assessment of bone marrow involvement and tumor extensions.

  10. Improved Polyimide Intumescent Coating

    NASA Technical Reports Server (NTRS)

    Salyer, I. O.; Fox, L. B.

    1984-01-01

    New polyimide intumescent coating uses titanium dioxide and glass microballons as nucleating agents to improve foaming characteristics of commercially-available polyimide precursor resin. Used for coating interior surfaces in commercial aircraft.

  11. Thermal barrier coating system

    NASA Technical Reports Server (NTRS)

    Stecura, S. (Inventor)

    1984-01-01

    A high temperature oxidation resistant, thermal barrier coating system is disclosed for a nickel cobalt, or iron base alloy substrate. An inner metal bond coating contacts the substrate, and a thermal barrier coating covers the bond coating. NiCrAlR, FeCrAlR, and CoCrAlR alloys are satisfactory as bond coating compositions where R=Y or Yb. These alloys contain, by weight, 24.9-36.7% chromium, 5.4-18.5% aluminum, and 0.05 to 1.55% yttrium or 0.05 to 0.53% ytterbium. The coatings containing ytterbium are preferred over those containing yttrium. An outer thermal barrier coating of partial stabilized zirconium oxide (zirconia) which is between 6% and 8%, by weight, of yttrium oxide (yttria) covers the bond coating. Partial stabilization provides a material with superior durability. Partially stabilized zirconia consists of mixtures of cubic, tetragonal, and monoclinic phases.

  12. Morphology, composition, and bioactivity of strontium-doped brushite coatings deposited on titanium implants via electrochemical deposition.

    PubMed

    Liang, Yongqiang; Li, Haoyan; Xu, Jiang; Li, Xin; Qi, Mengchun; Hu, Min

    2014-06-04

    Surface modification techniques have been applied to generate titanium implant surfaces that promote osseointegration for use in dental applications. In this study, strontium-doped brushite coatings were deposited on titanium by electrochemical deposition. The phase composition of the coating was investigated by energy dispersive X-ray spectroscopy and X-ray diffraction. The surface morphologies of the coatings were studied through scanning electron microscopy, and the cytocompatibility and bioactivity of the strontium-doped brushite coatings were evaluated using cultured osteoblasts. Osteoblast proliferation was enhanced by the addition of strontium, suggesting a possible mechanism by which strontium incorporation in brushite coatings increased bone formation surrounding the implants. Cell growth was also strongly influenced by the composition of the deposited coatings, with a 10% Sr-doped brushite coating inducing the greatest amount of bone formation among the tested materials.

  13. Bone healing of commercial oral implants with RGD immobilization through electrodeposited poly(ethylene glycol) in rabbit cancellous bone.

    PubMed

    Park, Jin-Woo; Kurashima, Kazuya; Tustusmi, Yusuke; An, Chang-Hyeon; Suh, Jo-Young; Doi, Hisashi; Nomura, Naoyuki; Noda, Kazuhiko; Hanawa, Takao

    2011-08-01

    Immobilization of RGD peptides on titanium (Ti) surfaces enhances implant bone healing by promoting early osteoblastic cell attachment and subsequent differentiation by facilitating integrin binding. Our previous studies have demonstrated the efficacy of RGD peptide immobilization on Ti surfaces through the electrodeposition of poly(ethylene glycol) (PEG) (RGD/PEG/Ti), which exhibited good chemical stability and bonding. The RGD/PEG/Ti surface promoted differentiation and mineralization of pre-osteoblasts. This study investigated the in vivo bone healing capacity of the RGD/PEG/Ti surface for biomedical application as a more osteoconductive implant surface in dentistry. The RGD/PEG/Ti surface was produced on an osteoconductive implant surface, i.e. the grit blasted micro-rough surface of a commercial oral implant. The osteoconductivity of the RGD/PEG/Ti surface was compared by histomorphometric evaluation with an RGD peptide-coated surface obtained by simple adsorption in rabbit cancellous bone after 2 and 4 weeks healing. The RGD/PEG/Ti implants displayed a high degree of direct bone apposition in cancellous bone and achieved greater active bone apposition, even in areas of poor surrounding bone. Significant increases in the bone to implant contact percentage were observed for RGD/PEG/Ti implants compared with RGD-coated Ti implants obtained by simple adsorption both after 2 and 4 weeks healing (P<0.05). These results demonstrate that RGD peptide immobilization on a Ti surface through electrodeposited PEG may be an effective method for enhancing bone healing with commercial micro-rough surface oral implants in cancellous bone by achieving rapid bone apposition on the implant surface.

  14. Coating Galvanized Steel

    DTIC Science & Technology

    1989-06-01

    phenolic drying oil products with a zinc dust-zinc oxide pigmentation. Roebuck et al. (Ref 3), state "For instance, coatings subject to saponification ...coating. All three types of TT-P-641 are subject to saponification , since they con- tain drying oils. The General Services Administration (GSA) sells con...penetration " Chemical degradation of coatings, particularly saponification of alkyd coatings in an alkaline environment " Differences in expansion and

  15. METHOD FOR TESTING COATINGS

    DOEpatents

    Johns, I.B.; Newton, A.S.

    1958-09-01

    A method is described for detecting pin hole imperfections in coatings on uranium-metal objects. Such coated objects are contacted with a heated atmosphere of gaseous hydrogen and imperfections present in the coatings will allow the uranlum to react with the hydrogen to form uranium hydride. Since uranium hydride is less dense than uranium metal it will swell, causing enlargement of the coating defeot and rendering it visible.

  16. Characterization of RSI coating

    NASA Technical Reports Server (NTRS)

    Miller, A. D.; Garofalini, S. H.; Smiser, L. W.; Mueller, J. I.

    1973-01-01

    X-ray diffraction analyses on mullite, silica, and ceramic mullite fiber coating materials to investigate the effects of thermal cycling, show that ceramic mullite fiber coating porosity is little affected by cycling to 1250 C and that material pores are mostly smaller than 15 nm. Some mullite coatings experience a slight increase in crystobalite with somewhat increased porosity. Silica coatings show a marked tendency to precipitate cristobalite with increased porosity and dimensional instability.

  17. Corrosion resistance of biodegradable Mg with a composite polymer coating.

    PubMed

    Chen, Peng; Sun, Jiadi; Zhu, Ye; Yu, Xun; Meng, Long; Li, Yang; Liu, Xiaoya

    2016-12-01

    Degrading Mg and its alloys are a category of implant materials for bone surgery, but rapid corrosion in physiological environment limits their clinical applications. To improve the corrosion resistance of Mg-based implants, a biodegradable composite polymer coating is deposited on an Mg rod in this work. The strategy is to decorate Mg surfaces with poly(γ-glutamic acid)-g-7-amino-4-methylcoumarin/hydroxyapatite (γ-PGA-g-AMC/HAp) composite nanoparticles through electrophoretic deposition in ethanol. The morphology and chemical composition of the resulting coating material are determined by scanning electron microscopy and Fourier transform infrared spectroscopy. Sample rods of bare Mg and coated Mg are implanted intramedullary into the femora of New Zealand white rabbits, periodic radiography and post-autopsy histopathology of each sample are analyzed. The obtained in vivo results clearly confirm that the coating material decreases degradation rate of the underlying Mg sample and appears good histocompatibility and osteoinductivity. The main aim of this work is to investigate the degradation process of bare Mg and coated Mg samples in bone environment and their effect on the surrounding bone tissue.

  18. Osteoconductive hydroxyapatite coated PEEK for spinal fusion surgery

    NASA Astrophysics Data System (ADS)

    Hahn, Byung-Dong; Park, Dong-Soo; Choi, Jong-Jin; Ryu, Jungho; Yoon, Woon-Ha; Choi, Joon-Hwan; Kim, Jong-Woo; Ahn, Cheol-Woo; Kim, Hyoun-Ee; Yoon, Byung-Ho; Jung, In-Kwon

    2013-10-01

    Polyetheretherketone (PEEK) has attracted much interest as biomaterial for interbody fusion cages due to its similar stiffness to bone and good radio-transparency for post-op visualization. Hydroxyapatite (HA) coating stimulates bone growth to the medical implant. The objective of this work is to make an implant consisting of biocompatible PEEK with an osteoconductive HA surface for spinal or orthopedic applications. Highly dense and well-adhered HA coating was developed on medical-grade PEEK using aerosol deposition (AD) without thermal degradation of the PEEK. The HA coating had a dense microstructure with no cracks or pores, and showed good adhesion to PEEK at adhesion strengths above 14.3 MPa. The crystallinity of the HA coating was remarkably enhanced by hydrothermal annealing as post-deposition heat-treatment. In addition, in vitro and in vivo biocompatibility of PEEK, in terms of cell adhesion morphology, cell proliferation, differentiation, and bone-to-implant contact ratio, were remarkably enhanced by the HA coating through AD.

  19. Calcium orthophosphate coatings on magnesium and its biodegradable alloys.

    PubMed

    Dorozhkin, Sergey V

    2014-07-01

    Biodegradable metals have been suggested as revolutionary biomaterials for bone-grafting therapies. Of these metals, magnesium (Mg) and its biodegradable alloys appear to be particularly attractive candidates due to their non-toxicity and as their mechanical properties match those of bones better than other metals do. Being light, biocompatible and biodegradable, Mg-based metallic implants have several advantages over other implantable metals currently in use, such as eliminating both the effects of stress shielding and the requirement of a second surgery for implant removal. Unfortunately, the fast degradation rates of Mg and its biodegradable alloys in the aggressive physiological environment impose limitations on their clinical applications. This necessitates development of implants with controlled degradation rates to match the kinetics of bone healing. Application of protective but biocompatible and biodegradable coatings able to delay the onset of Mg corrosion appears to be a reasonable solution. Since calcium orthophosphates are well tolerated by living organisms, they appear to be the excellent candidates for such coatings. Nevertheless, both the high chemical reactivity and the low melting point of Mg require specific parameters for successful deposition of calcium orthophosphate coatings. This review provides an overview of current coating techniques used for deposition of calcium orthophosphates on Mg and its biodegradable alloys. The literature analysis revealed that in all cases the calcium orthophosphate protective coatings both increased the corrosion resistance of Mg-based metallic biomaterials and improved their surface biocompatibility.

  20. [Bone involvement in endocrinopathies].

    PubMed

    Ribot, C; Trémollières, F; Pouillès, J M

    1994-06-04

    Progress in bone densitometry, particularly biphotonic absoptiometry, has made it possible to better identify the effects of endocrinopathies on bone. Both cortical and trabecular bone structures can be evaluated quantitatively and topographically revealing important information on the pathophysiology of bone loss. Sex hormones play a major role in the regulation of bone mineralization and hypogonadism, whatever the origin, can lead to deleterious effects. Bone loss is known to be significative in high performance female athletes with amenorrhoea; long-term consequences are not yet determined, but stress fractures have been reported in up to 50%. Other hypogonadisms leading to bone demineralization include anorexia nervosa, chronic intake of gonadotrophin releasing hormone analogues and anti-oestrogens, and hyperprolactinism. Hyperthyroidism leads to a negative calcium balance and demineralization with remodelling, predominantly in cortical bone. In hypothyroid states a 10% bone loss is observed in vertebrae. In both cases, bone densitometry should be performed in order to evaluate the effect of treatment. The deleterious effect of spontaneous or iatrogenic hypercortisism is well known, leading to spontaneous wedge fractures of the vertebrae due to predominating trabecular bone loss. The mechanism of action of corticosteroids on bone metabolism is complex, but the major effect is an inhibition of osteoblast maturation. Recovery may be possible, but no large long-term series have yet been reported. Hyperparathyroidism and acromegaly also affect bone mineralization. The information provided by bone densitometry is essential to properly manage patients with endocrinopathies affecting bone mineralization.

  1. Processing and Characterization of Functionally Graded Hydroxyapatite Coatings for Biomedical Implants

    NASA Astrophysics Data System (ADS)

    Bai, Xiao

    Hydroxyapatite [Ca10(PO4)6(OH) 2, HA] has been widely applied as a coating on various biomedical bone/dental implants to improve biocompatibility and bioactivity. It has been observed that primary reasons leading to implantation failure of commercial HA coated implants processed by plasma spraying are the poor mechanical properties of coatings and infections accompanied by implantation. It has been also reported an ideal coating should be able to stimulate new bone growth at the initial stage of implantation and stay stable both mechanically and chemically thereafter. This research has investigated a functionally graded hydroxyapatite (FGHA) coating that is capable of improving the stability of implants, facilitating recovery, and preventing infections after implantation. A series of FGHA coatings with incorporated Ag 0 ˜ 13.53 wt. % has been deposited onto Ti substrate using ion beam assisted deposition (IBAD) with in-situ heat treatment. The compositional, microstructural, mechanical, and biological properties of coatings have been analyzed via various tests. The relationship among processing parameters, coating properties and biological behaviors has been established and the processing parameters for processing FGHA coatings with/without incorporated Ag have been optimized. Microstructure observations of coating cross section via transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) for set temperature coatings deposited at 450°C ˜ 750°C reveals that in-situ substrate temperature is the primary factor controlling the crystallinity of the coatings. The microstructure observation of cross section via TEM/STEM for both FGHA coatings with/without incorporated Ag has shown that coatings are dense and have a gradually decreased crystallinity from substrate/coating interface to top surface. In particular, the interface has an atomically intermixed structure; the region near the interface has a columnar grain structure whereas

  2. PIT Coating Requirements Analysis

    SciTech Connect

    MINTEER, D.J.

    2000-10-20

    This study identifies the applicable requirements for procurement and installation of a coating intended for tank farm valve and pump pit interior surfaces. These requirements are intended to be incorporated into project specification documents and design media. This study also evaluates previously recommended coatings and identifies requirement-compliant coating products.

  3. Nanostructured Protective Coatings

    DTIC Science & Technology

    2006-01-01

    potential superior wear resistance properties. The Nanostructured Protective Coatings (NPC) program was designed to establish a collaborative team of...understanding of PVD parameters, depositing coatings on practical substrates such as the Ti6Al4V used for turbine blades , and developing a versatile...Nanostructured Protective Coatings (NPC) program was designed to establish a collaborative team of three entities (Pennsylvania State University

  4. Spin coating of electrolytes

    DOEpatents

    Stetter, Joseph R.; Maclay, G. Jordan

    1989-01-01

    Methods for spin coating electrolytic materials onto substrates are disclosed. More particularly, methods for depositing solid coatings of ion-conducting material onto planar substrates and onto electrodes are disclosed. These spin coating methods are employed to fabricate electrochemical sensors for use in measuring, detecting and quantifying gases and liquids.

  5. Ceramic with zircon coating

    NASA Technical Reports Server (NTRS)

    Wang, Hongyu (Inventor)

    2003-01-01

    An article comprises a silicon-containing substrate and a zircon coating. The article can comprise a silicon carbide/silicon (SiC/Si) substrate, a zircon (ZrSiO.sub.4) intermediate coating and an external environmental/thermal barrier coating.

  6. Commercial Fastener Coatings Doerken

    DTIC Science & Technology

    2010-06-01

    Phosphating* *partly recommended Dip Spinning Dipping Spraying Spin coating Conveyor oven box oven Inductive drying Pretreatment Coating Preheating...Curing Cooling Application Techniques - Dip Spin Coating Gurtbnd Cross BarTranspo" Band beiCifteiE Vo12one Vent llated Pre .Zone Cros~ Bar T ransrt

  7. Phase stability and biological property evaluation of plasma sprayed hydroxyapatite coatings for orthopedic and dental applications.

    PubMed

    Vahabzadeh, Sahar; Roy, Mangal; Bandyopadhyay, Amit; Bose, Susmita

    2015-04-01

    In this work we have investigated the effects of strontium (Sr) dopant on in vitro protein release kinetics and in vivo osteogenic properties of plasma sprayed hydroxyapatite (HA) coatings, along with their dissolution behavior. Plasma sprayed HA coatings are widely used in load-bearing implants. Apart from osseointegration, the new generation of HA coating is expected to deliver biomolecules and/or drugs that can induce osteoinduction. This paper reports the preparation of crystalline and amorphous HA coatings on commercially pure titanium (Cp-Ti) using inductively coupled radio frequency (RF) plasma spray, and their stability at different solution pH. Coatings prepared at 110 mm working distance from the nozzle showed an average Ca ion release of 18 and 90 ppm in neutral and acidic environments, respectively. Decreasing the working distance to 90 mm resulted in the formation of a coating with less crystalline HA and phases with higher solubility products, and consequently higher dissolution over 32 days. A 92% release of a model protein bovine serum albumin (BSA) in phosphate buffer with pH of 7.4 was measured for Sr-doped HA (Sr-HA) coating, while only a 72% release could be measured for pure HA coating. Distortion of BSA during adsorption on coatings revealed a strong interaction between the protein and the coating, with an increase in α-helix content. Osteoid formation was found on Sr-HA implants as early as 7 weeks post implantation compared to HA coated and uncoated Ti implants. After 12 weeks post implantation, osteoid new bone was formed on HA implants; whereas, bone mineralization started on Sr-HA samples. While no osteoid was formed on bare Ti surfaces, bone was completely mineralized on HA and Sr-HA coatings after 16 weeks post implantation. Our results show that both phase stability and chemistry can have a significant influence toward in vitro and in vivo response of HA coatings on Ti implants.

  8. Simple Coating with Fibronectin Fragment Enhances Stainless Steel Screw Osseointegration in Healthy and Osteoporotic Rats

    PubMed Central

    Agarwal, Rachit; González-García, Cristina; Torstrick, Brennan; Guldberg, Robert E.; Salmerón-Sánchez, Manuel; García, Andrés J.

    2015-01-01

    Metal implants are widely used to provide structural support and stability in current surgical treatments for bone fractures, spinal fusions, and joint arthroplasties as well as craniofacial and dental applications. Early implant-bone mechanical fixation is an important requirement for the successful performance of such implants. However, adequate osseointegration has been difficult to achieve especially in challenging disease states like osteoporosis due to reduced bone mass and strength. Here, we present a simple coating strategy based on passive adsorption of FN7-10, a recombinant fragment of human fibronectin encompassing the major cell adhesive, integrin-binding site, onto 316-grade stainless steel (SS). FN7-10 coating on SS surfaces promoted α5β1 integrin-dependent adhesion and osteogenic differentiation of human mesenchymal stem cells. FN7-10-coated SS screws increased bone-implant mechanical fixation compared to uncoated screws by 30% and 45% at 1 and 3 months, respectively, in healthy rats. Importantly, FN7-10 coating significantly enhanced bone-screw fixation by 57% and 32% at 1 and 3 months, respectively, and bone-implant ingrowth by 30% at 3 months compared to uncoated screws in osteoporotic rats. These coatings are easy to apply intra-operatively, even to implants with complex geometries and structures, facilitating the potential for rapid translation to clinical settings. PMID:26100343

  9. Simple coating with fibronectin fragment enhances stainless steel screw osseointegration in healthy and osteoporotic rats.

    PubMed

    Agarwal, Rachit; González-García, Cristina; Torstrick, Brennan; Guldberg, Robert E; Salmerón-Sánchez, Manuel; García, Andrés J

    2015-09-01

    Metal implants are widely used to provide structural support and stability in current surgical treatments for bone fractures, spinal fusions, and joint arthroplasties as well as craniofacial and dental applications. Early implant-bone mechanical fixation is an important requirement for the successful performance of such implants. However, adequate osseointegration has been difficult to achieve especially in challenging disease states like osteoporosis due to reduced bone mass and strength. Here, we present a simple coating strategy based on passive adsorption of FN7-10, a recombinant fragment of human fibronectin encompassing the major cell adhesive, integrin-binding site, onto 316-grade stainless steel (SS). FN7-10 coating on SS surfaces promoted α5β1 integrin-dependent adhesion and osteogenic differentiation of human mesenchymal stem cells. FN7-10-coated SS screws increased bone-implant mechanical fixation compared to uncoated screws by 30% and 45% at 1 and 3 months, respectively, in healthy rats. Importantly, FN7-10 coating significantly enhanced bone-screw fixation by 57% and 32% at 1 and 3 months, respectively, and bone-implant ingrowth by 30% at 3 months compared to uncoated screws in osteoporotic rats. These coatings are easy to apply intra-operatively, even to implants with complex geometries and structures, facilitating the potential for rapid translation to clinical settings.

  10. Preparation and characterizations of bioglass ceramic cement/Ca-P coating on pure magnesium for biomedical applications.

    PubMed

    Zhang, Xue; Li, Xiao-Wu; Li, Ji-Guang; Sun, Xu-Dong

    2014-01-08

    Magnesium has been recently recognized as a biodegradable metal for bone substitute applications. In order to improve the biocompatibility and osteointegration of pure Mg, two kinds of coatings, i.e., the Ca-P coating and bioglass ceramic cement (BGCC)/Ca-P coating, were prepared on the pure Mg ribbons in the present work. The Ca-P coating was obtained by aqueous solution method. Subsequently, Ca-P coated Mg was immersed into the BGCC slurry, which was prepared by the mix of SiO2-CaO-P2O5 bioglass ceramic (BGC) powders and phosphate liquid with a liquid-to-solid ratio (L/S) of 1.6, to obtain BGCC/Ca-P coating by a dipping-pulling method. The microstructures, morphologies, and compositions of these coatings have been characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS). The effect of these coatings on the mineralization activity of pure Mg has been investigated. The results indicated that both the Ca-P coating and BGCC/Ca-P coating could promote the nucleation of osteoconductive minerals, i.e., bone-like apatite, and the hydroxyapatite (HA) layer formed on the surface of the BGCC/Ca-P coating is obviously more dense, thick, and stable than that formed on the Ca-P coating after immersion in SBF solution for 15 days. The potentiodynamic polarization test indicated that the corrosion current density of the BGCC/Ca-P coated Mg is obviously lower than that of the Ca-P coating and 10 times lower than that of uncoated Mg. These results demonstrated that the BGCC/Ca-P coating can increase significantly the corrosion resistance of Mg and introduce a high biocompatibility of the bone-Mg substrate interface. In summary, the newly developed BGCC/Ca-P coated Mg has a good potential for biomedical applications.

  11. Aircraft surface coatings

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Liquid, spray on elastomeric polyurethanes are selected and investigated as best candidates for aircraft external protective coatings. Flight tests are conducted to measure drag effects of these coatings compared to paints and a bare metal surface. The durability of two elastometric polyurethanes are assessed in airline flight service evaluations. Laboratory tests are performed to determine corrosion protection properties, compatibility with aircraft thermal anti-icing systems, the effect of coating thickness on erosion durability, and the erosion characteristics of composite leading edges-bare and coated. A cost and benefits assessment is made to determine the economic value of various coating configurations to the airlines.

  12. Antibacterial polymer coatings.

    SciTech Connect

    Wilson, Mollye C.; Allen, Ashley N.; Barnhart, Meghan; Tucker, Mark David; Hibbs, Michael R.

    2009-09-01

    A series of poly(sulfone)s with quaternary ammonium groups and another series with aldehyde groups are synthesized and tested for biocidal activity against vegetative bacteria and spores, respectively. The polymers are sprayed onto substrates as coatings which are then exposed to aqueous suspensions of organisms. The coatings are inherently biocidal and do not release any agents into the environment. The coatings adhere well to both glass and CARC-coated coupons and they exhibit significant biotoxicity. The most effective quaternary ammonium polymers kills 99.9% of both gram negative and gram positive bacteria and the best aldehyde coating kills 81% of the spores on its surface.

  13. Thermal barrier coating system

    NASA Technical Reports Server (NTRS)

    Stecura, S.; Leibert, C. H. (Inventor)

    1977-01-01

    A coating system which contains a bond coating and a thermal barrier coating is applied to metal surfaces such as turbine blades and provides both low thermal conductivity and improved adherence when exposed to high temperature gases or liquids. The bond coating contains NiCrAlY and the thermal barrier coating contains a reflective oxide. The reflective oxides ZrO2-Y2O3 and ZrO2-MgO have demonstrated significant utility in high temperature turbine applications.

  14. Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    1993-01-01

    In order to reduce heat transfer between a hot gas heat source and a metallic engine component, a thermal insulating layer of material is placed between them. This thermal barrier coating is applied by plasma spray processing the thin films. The coating has been successfully employed in aerospace applications for many years. Lewis Research Center, a leader in the development engine components coating technology, has assisted Caterpillar, Inc. in applying ceramic thermal barrier coatings on engines. Because these large engines use heavy fuels containing vanadium, engine valve life is sharply decreased. The barrier coating controls temperatures, extends valve life and reduces operating cost. Additional applications are currently under development.

  15. Hidroxyapatite Coating on CoCrMo Alloy Titanium Nitride Coated Using Biomimetic Method

    NASA Astrophysics Data System (ADS)

    Charlena; Sukaryo, S. G.; Fajar, M.

    2016-11-01

    Bone implants is a way to cure broken bones which is being developed. The implants can be made of metals, ceramics and polymers. Metallic materials commonly used are titanium (Ti), stainless steel, and metal alloys. This study used Co-based alloys, i.e. CoCrMo coated with titanium nitride (TiN) which was then coated on hidroxyapatite (HAp). The HAp coating on the surface of CoCrMo alloy was done by biomimetic methods, first by soaking the metal alloys in simulated body fluid (SBF) solution for 18, 24, and 36 hours. The immersion in the SBF solution produced white coat on the surface of the metal alloy. The layers formed were analyzed by scanning electron microscope (SEM) and characterized by x-ray diffractometer (XRD). Based on the SEM results of 36 hours treatment, the morphology of apatite crystal formed fine grains. According to XRD result, there were HAp peaks at angles 2θ 31.86, 32.25, dan 39.48. However, there were also CaCO3 peaks at angles 2θ 29.46, 36.04, and 46.79. It indicated the pure HAp is not yet formed.

  16. Factors stimulating bone formation.

    PubMed

    Lind, M; Bünger, C

    2001-10-01

    The aim of this review is to describe major approaches for stimulating bone healing and to review other factors affecting bone healing. Spinal bone fusion after surgery is a demanding process requiring optimal conditions for clinical success. Bone formation and healing can be enhanced through various methods. Experimental studies have revealed an array of stimulative measures. These include biochemical stimulation by use of hormones and growth factors, physical stimulation through mechanical and electromagnetic measures, and bone grafting by use of bone tissue or bone substitutes. Newer biological techniques such as stem cell transplantation and gene therapy can also be used to stimulate bone healing. Apart from bone transplantation, clinical experience with the many stimulation modalities is limited. Possible areas for clinical use of these novel methods are discussed.

  17. Regulation of Bone Metabolism

    PubMed Central

    Shahi, Maryam; Peymani, Amir; Sahmani, Mehdi

    2017-01-01

    Bone is formed through the processes of endochondral and intramembranous ossification. In endochondral ossification primary mesenchymal cells differentiate to chondrocytes and then are progressively substituted by bone, while in intramembranous ossification mesenchymal stem cells (MSCs) differentiate directly into osteoblasts to form bone. The steps of osteogenic proliferation, differentiation, and bone homeostasis are controlled by various markers and signaling pathways. Bone needs to be remodeled to maintain integrity with osteoblasts, which are bone-forming cells, and osteoclasts, which are bone-degrading cells.In this review we considered the major factors and signaling pathways in bone formation; these include fibroblast growth factors (FGFs), bone morphogenetic proteins (BMPs), wingless-type (Wnt) genes, runt-related transcription factor 2 (RUNX2) and osteoblast-specific transcription factor (osterix or OSX). PMID:28367467

  18. Bisphosphonates and bone quality

    PubMed Central

    Pazianas, Michael; van der Geest, Stefan; Miller, Paul

    2014-01-01

    Bisphosphonates (BPs) are bone-avid compounds used as first-line medications for the prevention and treatment of osteoporosis. They are also used in other skeletal pathologies such as Paget's and metastatic bone disease. They effectively reduce osteoclast viability and also activity in the resorptive phase of bone remodelling and help preserve bone micro-architecture, both major determinants of bone strength and ultimately of the susceptibility to fractures. The chemically distinctive structure of each BP used in the clinic determines their unique affinity, distribution/penetration throughout the bone and their individual effects on bone geometry, micro-architecture and composition or what we call ‘bone quality'. BPs have no clinically significant anabolic effects. This review will touch upon some of the components of bone quality that could be affected by the administration of BPs. PMID:24876930

  19. [Microdestruction of the bone].

    PubMed

    Iankovskiĭ, V É

    2014-01-01

    The objective of the present study was the detection of microcracks in the compact bone tissue surrounding the fracture and in deformed bone undergoing subcritical loading. The portions of deformed bone tissue and terminal fragments of broken bones were obtained in the form of blocks longitudinally sawcut from the regions of primary and secondary bone rupture. A total of 300 such blocks were available for the examination. All portions of the deformed bone tissue and terminal fragments of broken bones showed up microcracks commensurate with the bone structures. They were actually hardened traces of deformation that preceded the fracture and reflected the volume of the destroyed bone tissue; moreover, in certain cases they allowed to identify the kind of the object that exerted the external action (either a blow or slow bending).

  20. Regulation of Bone Metabolism.

    PubMed

    Shahi, Maryam; Peymani, Amir; Sahmani, Mehdi

    2017-04-01

    Bone is formed through the processes of endochondral and intramembranous ossification. In endochondral ossification primary mesenchymal cells differentiate to chondrocytes and then are progressively substituted by bone, while in intramembranous ossification mesenchymal stem cells (MSCs) differentiate directly into osteoblasts to form bone. The steps of osteogenic proliferation, differentiation, and bone homeostasis are controlled by various markers and signaling pathways. Bone needs to be remodeled to maintain integrity with osteoblasts, which are bone-forming cells, and osteoclasts, which are bone-degrading cells.In this review we considered the major factors and signaling pathways in bone formation; these include fibroblast growth factors (FGFs), bone morphogenetic proteins (BMPs), wingless-type (Wnt) genes, runt-related transcription factor 2 (RUNX2) and osteoblast-specific transcription factor (osterix or OSX).

  1. Formation of Solution-derived Hydroxyapatite Coatings on Titanium Alloy in the Presence of Magnetron-sputtered Alumina Bond Coats.

    PubMed

    Zykova, Anna; Safonov, Vladimir; Yanovska, Anna; Sukhodub, Leonid; Rogovskaya, Renata; Smolik, Jerzy; Yakovin, Stas

    2015-01-01

    Hydroxyapatite Ca10(PO4)6(OH)2 (HAp) and calcium phosphate ceramic materials and coatings are widely used in medicine and dentistry because of their ability to enhance the tissue response to implant surfaces and promote bone ingrowth and osseoconduction processes. The deposition conditions have a great influence on the structure and biofunctionality of calcium phosphate coatings. Corrosion processes and poor adhesion to substrate material reduce the lifetime of implants with calcium phosphate coatings. The research has focused on the development of advanced methods to deposit double-layered ceramic oxide/calcium phosphate coatings by a hybrid technique of magnetron sputtering and thermal methods. The thermal method can promote the crystallization and the formation of HAp coatings on titanium alloy Ti6Al4V substrates at low temperature, based on the principle that the solubility of HAp in aqueous solutions decreases with increasing substrate temperature. By this method, hydroxyapatite directly coated the substrate without precipitation in the initial solution. Using a thermal substrate method, calcium phosphate coatings were prepared at substrate temperatures of 100-105 (o)C. The coated metallic implant surfaces with ceramic bond coats and calcium phosphate layers combine the excellent mechanical properties of metals with the chemical stability of ceramic materials. The corrosion test results show that the ceramic oxide (alumina) coatings and the double-layered alumina-calcium phosphate coatings improve the corrosion resistance compared with uncoated Ti6Al4V and single-layered Ti6Al4V/calcium phosphate substrates. In addition, the double-layered alumina/hydroxyapatite coatings demonstrate the best biocompatibility during in vitro tests.

  2. Formation of Solution-derived Hydroxyapatite Coatings on Titanium Alloy in the Presence of Magnetron-sputtered Alumina Bond Coats

    PubMed Central

    Zykova, Anna; Safonov, Vladimir; Yanovska, Anna; Sukhodub, Leonid; Rogovskaya, Renata; Smolik, Jerzy; Yakovin, Stas

    2015-01-01

    Hydroxyapatite Ca10(PO4)6(OH)2 (HAp) and calcium phosphate ceramic materials and coatings are widely used in medicine and dentistry because of their ability to enhance the tissue response to implant surfaces and promote bone ingrowth and osseoconduction processes. The deposition conditions have a great influence on the structure and biofunctionality of calcium phosphate coatings. Corrosion processes and poor adhesion to substrate material reduce the lifetime of implants with calcium phosphate coatings. The research has focused on the development of advanced methods to deposit double-layered ceramic oxide/calcium phosphate coatings by a hybrid technique of magnetron sputtering and thermal methods. The thermal method can promote the crystallization and the formation of HAp coatings on titanium alloy Ti6Al4V substrates at low temperature, based on the principle that the solubility of HAp in aqueous solutions decreases with increasing substrate temperature. By this method, hydroxyapatite directly coated the substrate without precipitation in the initial solution. Using a thermal substrate method, calcium phosphate coatings were prepared at substrate temperatures of 100-105 oC. The coated metallic implant surfaces with ceramic bond coats and calcium phosphate layers combine the excellent mechanical properties of metals with the chemical stability of ceramic materials. The corrosion test results show that the ceramic oxide (alumina) coatings and the double-layered alumina-calcium phosphate coatings improve the corrosion resistance compared with uncoated Ti6Al4V and single-layered Ti6Al4V/calcium phosphate substrates. In addition, the double-layered alumina/hydroxyapatite coatings demonstrate the best biocompatibility during in vitro tests. PMID:25893018

  3. Bacillus subtilis Spore Coat

    PubMed Central

    Driks, Adam

    1999-01-01

    In response to starvation, bacilli and clostridia undergo a specialized program of development that results in the production of a highly resistant dormant cell type known as the spore. A proteinacious shell, called the coat, encases the spore and plays a major role in spore survival. The coat is composed of over 25 polypeptide species, organized into several morphologically distinct layers. The mechanisms that guide coat assembly have been largely unknown until recently. We now know that proper formation of the coat relies on the genetic program that guides the synthesis of spore components during development as well as on morphogenetic proteins dedicated to coat assembly. Over 20 structural and morphogenetic genes have been cloned. In this review, we consider the contributions of the known coat and morphogenetic proteins to coat function and assembly. We present a model that describes how morphogenetic proteins direct coat assembly to the specific subcellular site of the nascent spore surface and how they establish the coat layers. We also discuss the importance of posttranslational processing of coat proteins in coat morphogenesis. Finally, we review some of the major outstanding questions in the field. PMID:10066829

  4. Coatings for directional eutectics

    NASA Technical Reports Server (NTRS)

    Rairden, J. R.; Jackson, M. R.

    1976-01-01

    Significant advances have been made in the development of an environmentally stable coating for a very high strength, directionally solidified eutectic alloy designated NiTaC-13. Three duplex (two-layer) coatings survived 3,000 hours on a cyclic oxidation test (1,100 C to 90 C). These coatings were fabricated by first depositing a layer of NiCrAl(Y) by vacuum evaporation from an electron beam heated source, followed by depositing an aluminizing overlayer. The alloy after exposure with these coatings was denuded of carbide fibers at the substrate/coating interface. It was demonstrated that TaC fiber denudation can be greatly retarded by applying a carbon-bearing coating. The coating was applied by thermal spraying followed by aluminization. Specimens coated with NiCrAlCY+Al survived over 2,000 hours in the cyclic oxidation test with essentially no TaC denudation. Coating ductility was studied for coated and heat-treated bars, and stress rupture life at 871 C and 1,100 C was determined for coated and cycled bars.

  5. Strain isolated ceramic coatings

    NASA Technical Reports Server (NTRS)

    Tolokan, R. P.; Brady, J. B.; Jarrabet, G. P.

    1985-01-01

    Plasma sprayed ceramic coatings are used in gas turbine engines to improve component temperature capability and cooling air efficiency. A compliant metal fiber strain isolator between a plasma sprayed ceramic coating and a metal substrate improves ceramic durability while allowing thicker coatings for better insulation. Development of strain isolated coatings has concentrated on design and fabrication of coatings and coating evaluation via thermal shock testing. In thermal shock testing, five types of failure are possible: buckling failure im compression on heat up, bimetal type failure, isothermal expansion mismatch failure, mudflat cracking during cool down, and long term fatigue. A primary failure mode for thermally cycled coatings is designated bimetal type failure. Bimetal failure is tensile failure in the ceramic near the ceramic-metal interface. One of the significant benefits of the strain isolator is an insulating layer protecting the metal substrate from heat deformation and thereby preventing bimetal type failure.

  6. Coated Aerogel Beads

    NASA Technical Reports Server (NTRS)

    Littman, Howard (Inventor); Plawsky, Joel L. (Inventor); Paccione, John D. (Inventor)

    2014-01-01

    Methods and apparatus for coating particulate material are provided. The apparatus includes a vessel having a top and a bottom, a vertically extending conduit having an inlet in the vessel and an outlet outside of the vessel, a first fluid inlet in the bottom of the vessel for introducing a transfer fluid, a second fluid inlet in the bottom of the vessel for introducing a coating fluid, and a fluid outlet from the vessel. The method includes steps of agitating a material, contacting the material with a coating material, and drying the coating material to produce a coated material. The invention may be adapted to coat aerogel beads, among other materials. A coated aerogel bead and an aerogel-based insulation material are also disclosed.

  7. Bone-immune cell crosstalk: bone diseases.

    PubMed

    Mori, Giorgio; D'Amelio, Patrizia; Faccio, Roberta; Brunetti, Giacomina

    2015-01-01

    Bone diseases are associated with great morbidity; thus, the understanding of the mechanisms leading to their development represents a great challenge to improve bone health. Recent reports suggest that a large number of molecules produced by immune cells affect bone cell activity. However, the mechanisms are incompletely understood. This review aims to shed new lights into the mechanisms of bone diseases involving immune cells. In particular, we focused our attention on the major pathogenic mechanism underlying periodontal disease, psoriatic arthritis, postmenopausal osteoporosis, glucocorticoid-induced osteoporosis, metastatic solid tumors, and multiple myeloma.

  8. Macroporous bioceramics: a remarkable material for bone regeneration.

    PubMed

    Lew, Kien-Seng; Othman, Radzali; Ishikawa, Kunio; Yeoh, Fei-Yee

    2012-09-01

    This review summarises the major developments of macroporous bioceramics used mainly for repairing bone defects. Porous bioceramics have been receiving attention ever since their larger surface area was reported to be beneficial for the formation of more rigid bonds with host tissues. The study of porous bioceramics is important to overcome the less favourable bonds formed between dense bioceramics and host tissues, especially in healing bone defects. Macroporous bioceramics, which have been studied extensively, include hydroxyapatite, tricalcium phosphate, alumina, and zirconia. The pore size and interconnections both have significant effects on the growth rate of bone tissues. The optimum pore size of hydroxyapatite scaffolds for bone growth was found to be 300 µm. The existence of interconnections between pores is critical during the initial stage of tissue ingrowth on porous hydroxyapatite scaffolds. Furthermore, pore formation on β-tricalcium phosphate scaffolds also allowed the impregnation of growth factors and cells to improve bone tissues growth significantly. The formation of vascularised tissues was observed on macroporous alumina but did not take place in the case of dense alumina due to its bioinert nature. A macroporous alumina coating on scaffolds was able to improve the overall mechanical properties, and it enabled the impregnation of bioactive materials that could increase the bone growth rate. Despite the bioinertness of zirconia, porous zirconia was useful in designing scaffolds with superior mechanical properties after being coated with bioactive materials. The pores in zirconia were believed to improve the bone growth on the coated system. In summary, although the formation of pores in bioceramics may adversely affect mechanical properties, the advantages provided by the pores are crucial in repairing bone defects.

  9. Combustion chemical vapor desposited coatings for thermal barrier coating systems

    SciTech Connect

    Hampikian, J.M.; Carter, W.B.

    1995-10-01

    The new deposition process, combustion chemical vapor deposition, shows a great deal of promise in the area of thermal barrier coating systems. This technique produces dense, adherent coatings, and does not require a reaction chamber. Coatings can therefore be applied in the open atmosphere. The process is potentially suitable for producing high quality CVD coatings for use as interlayers between the bond coat and thermal barrier coating, and/or as overlayers, on top of thermal barrier coatings.

  10. Molecular plasma deposition: biologically inspired nanohydroxyapatite coatings on anodized nanotubular titanium for improving osteoblast density

    PubMed Central

    Balasundaram, Ganesan; Storey, Daniel M; Webster, Thomas J

    2015-01-01

    In order to begin to prepare a novel orthopedic implant that mimics the natural bone environment, the objective of this in vitro study was to synthesize nanocrystalline hydroxyapatite (NHA) and coat it on titanium (Ti) using molecular plasma deposition (MPD). NHA was synthesized through a wet chemical process followed by a hydrothermal treatment. NHA and micron sized hydroxyapatite (MHA) were prepared by processing NHA coatings at 500°C and 900°C, respectively. The coatings were characterized before and after sintering using scanning electron microscopy, atomic force microscopy, and X-ray diffraction. The results revealed that the post-MPD heat treatment of up to 500°C effectively restored the structural and topographical integrity of NHA. In order to determine the in vitro biological responses of the MPD-coated surfaces, the attachment and spreading of osteoblasts (bone-forming cells) on the uncoated, NHA-coated, and MHA-coated anodized Ti were investigated. Most importantly, the NHA-coated substrates supported a larger number of adherent cells than the MHA-coated and uncoated substrates. The morphology of these cells was assessed by scanning electron microscopy and the observed shapes were different for each substrate type. The present results are the first reports using MPD in the framework of hydroxyapatite coatings on Ti to enhance osteoblast responses and encourage further studies on MPD-based hydroxyapatite coatings on Ti for improved orthopedic applications. PMID:25609958

  11. Molecular plasma deposition: biologically inspired nanohydroxyapatite coatings on anodized nanotubular titanium for improving osteoblast density.

    PubMed

    Balasundaram, Ganesan; Storey, Daniel M; Webster, Thomas J

    2015-01-01

    In order to begin to prepare a novel orthopedic implant that mimics the natural bone environment, the objective of this in vitro study was to synthesize nanocrystalline hydroxyapatite (NHA) and coat it on titanium (Ti) using molecular plasma deposition (MPD). NHA was synthesized through a wet chemical process followed by a hydrothermal treatment. NHA and micron sized hydroxyapatite (MHA) were prepared by processing NHA coatings at 500°C and 900°C, respectively. The coatings were characterized before and after sintering using scanning electron microscopy, atomic force microscopy, and X-ray diffraction. The results revealed that the post-MPD heat treatment of up to 500°C effectively restored the structural and topographical integrity of NHA. In order to determine the in vitro biological responses of the MPD-coated surfaces, the attachment and spreading of osteoblasts (bone-forming cells) on the uncoated, NHA-coated, and MHA-coated anodized Ti were investigated. Most importantly, the NHA-coated substrates supported a larger number of adherent cells than the MHA-coated and uncoated substrates. The morphology of these cells was assessed by scanning electron microscopy and the observed shapes were different for each substrate type. The present results are the first reports using MPD in the framework of hydroxyapatite coatings on Ti to enhance osteoblast responses and encourage further studies on MPD-based hydroxyapatite coatings on Ti for improved orthopedic applications.

  12. Plasma Sprayed Hydroxyapatite Coatings: Influence of Spraying Power on Microstructure

    SciTech Connect

    Mohd, S. M.; Abd, M. Z.; Abd, A. N.

    2010-03-11

    The plasma sprayed hydroxyapatite (HA) coatings are used on metallic implants to enhance the bonding between the implant and bone in human body. The coating process was implemented at different spraying power for each spraying condition. The coatings formed from a rapid solidification of molten and partly molten particles that impact on the surface of substrate at high velocity and high temperature. The study was concentrated on different spraying power that is between 23 to 31 kW. The effect of different power on the coatings microstructure was investigated using scanning electron microscope (SEM) and phase composition was evaluated using X-ray diffraction (XRD) analysis. The coatings surface morphology showed distribution of molten, partially melted particles and some micro-cracks. The produced coatings were found to be porous as observed from the cross-sectional morphology. The coatings XRD results indicated the presence of crystalline phase of HA and each of the patterns was similar to the initial powder. Regardless of different spraying power, all the coatings were having similar XRD patterns.

  13. Biomimetic calcium phosphate coatings on Polyactive 1000/70/30.

    PubMed

    Du, C; Klasens, P; Haan, R E; Bezemer, J; Cui, F Z; de Groot, K; Layrolle, P

    2002-03-05

    Precalcification of Polyactive 1000/70/30 with a biomimetic calcium phosphate coating is expected to enhance the bioactivity of this biodegradable polymer for the application as bone filler or scaffold of bone tissue engineering. This study presents a 1-day one-step incubation method to obtain either amorphous or bone-like apatitic calcium phosphate coating on Polyactive 1000/70/30. Either dense plates or three-dimensional porous blocks of the polymer were incubated in a simplified but concentrated simulated body fluid-derived solution at 37 degrees C. By bubbling CO2 gas, a solution was prepared with calcium and phosphate ion concentrations five times of that of regular simulated body fluid. With controlled stirring, the CO2 was released out of the solution and exchanged by air. The pH of the solution increased to induce coating formation. Adjusting stirring rate and CO2/air exchange rate controlled the process kinetics. The reaction kinetics had little influence on the crystallographic structure of the final coating mineral for a given solution composition as shown by Fourier transform infrared spectroscopy and X-ray diffraction. However, the interface structure between the coating and substrate was kinetics-dependent. A fast precipitation condition resulted in a uniform but superficial calcification pattern at the surface of polymer. A slow process by selecting either a slow stirring or a slow CO2/air exchange, on the contrary, induced a localized but deep inside calcification pattern. A tensile test showed no statistically significant difference in the mechanical properties among uncoated and coated polymers. The cracking behavior of coatings from different kinetics, however, exhibited different manners, as can be attributed to different interface structures and interfacial strengths.

  14. A biodegradable gentamicin-hydroxyapatite-coating for infection prophylaxis in cementless hip prostheses.

    PubMed

    Neut, D; Dijkstra, R J; Thompson, J I; Kavanagh, C; van der Mei, H C; Busscher, H J

    2015-01-02

    A degradable, poly (lactic-co-glycolic acid) (PLGA), gentamicin-loaded prophylactic coating for hydroxyapatite (HA)-coated cementless hip prostheses is developed with similar antibacterial efficacy as offered by gentamicin-loaded cements for fixing traditional, cemented prostheses in bone. We describe the development pathway, from in vitro investigation of antibiotic release and antibacterial properties of this PLGA-gentamicin-HA-coating in different in vitro models to an evaluation of its efficacy in preventing implant-related infection in rabbits. Bone in-growth in the absence and presence of the coating was investigated in a canine model. The PLGA-gentamicin-HA-coating showed high-burst release, with antibacterial efficacy in agar-assays completely disappearing after 4 days, minimising risk of inducing antibiotic resistance. Gentamicin-sensitive and gentamicin-resistant staphylococci were killed by the antibiotic-loaded coating, in a simulated prosthesis-related interfacial gap. PLGA-gentamicin-HA-coatings prevented growth of bioluminescent staphylococci around a miniature-stem mounted in bacterially contaminated agar, as observed using bio-optical imaging. PLGA-gentamicin-HA-coated pins inserted in bacterially contaminated medullary canals in rabbits caused a statistically significant reduction in infection rates compared to HA-coated pins without gentamicin. Bone ingrowth to PLGA-gentamicin-HA-coated pins, in condylar defects of Beagle dogs was not impaired by the presence of the degradable, gentamicin-loaded coating. In conclusion, the PLGA-gentamicin-HA-coating constitutes an effective strategy for infection prophylaxis in cementless prostheses.

  15. A Hybrid Laser/Aerosol Method for the Synthesis of Porous Nanostructured Calcium Phosphate Materials for Bone Tissue Engineering Applications

    DTIC Science & Technology

    2005-01-01

    carbon-based materials [4]. Nanostructured calcium phosphate bioceramics comprising mixtures of resorbable and nonresorbable calcium phosphate phases are...over the phase composition and microstructure of coatings of these mixtures, establishing them as suitable bioceramic substrates for bone tissue

  16. Influence of PEEK Coating on Hip Implant Stress Shielding: A Finite Element Analysis

    PubMed Central

    Anguiano-Sanchez, Jesica; Martinez-Romero, Oscar; Siller, Hector R.; Diaz-Elizondo, Jose A.; Flores-Villalba, Eduardo

    2016-01-01

    Stress shielding is a well-known failure factor in hip implants. This work proposes a design concept for hip implants, using a combination of metallic stem with a polymer coating (polyether ether ketone (PEEK)). The proposed design concept is simulated using titanium alloy stems and PEEK coatings with thicknesses varying from 100 to 400 μm. The Finite Element analysis of the cancellous bone surrounding the implant shows promising results. The effective von Mises stress increases between 81 and 92% for the complete volume of cancellous bone. When focusing on the proximal zone of the implant, the increased stress transmission to the cancellous bone reaches between 47 and 60%. This increment in load transferred to the bone can influence mineral bone loss due to stress shielding, minimizing such effect, and thus prolonging implant lifespan. PMID:27051460

  17. Tailored coatings for hardfacing

    SciTech Connect

    Dustoor, M.R.; Moskowitz, L.N.

    1984-01-01

    An update on Conforma Clad coatings, first presented at the 1982 National Powder Metallurgy Conference in Montreal, Canada, is presented. The major advantage is the ability to offer selective-area coatings in a wide range of thicknesses and material choices while retaining dimensional and edge control of the coating. Complex geometries can be coated with a high materials utilization and with coating properties tailored to the end application. Porosity and bond strength values can match or exceed those seen with the best commercially available thermal sprayed coatings. The ability of the process to balance abrasion resistance and toughness requirements for a specific wear mode, is illustrated by microstructural control of the size, shape and density of carbide particles contained in the coatings. Dry sand abrasive test data are provided on Conforma Clad coatings and competitive processes. Ongoing developments of non-furnace fusion techniques, such as laser cladding, are presented and the microstructures compared with those obtained with conventional coating processes. Commercial applications for these coatings are highlighted with some typical examples.

  18. Porous biphasic calcium phosphate ceramics coated with nano-hydroxyapatite and seeded with mesenchymal stem cells for reconstruction of radius segmental defects in rabbits.

    PubMed

    Hu, Jianzhong; Yang, Zhiming; Zhou, Yongchun; Liu, Yong; Li, Kaiyang; Lu, Hongbin

    2015-11-01

    The osteoconduction of porous biphasic calcium phosphate (BCP) ceramics has been widely reported. In a previous study, we demonstrated that applying a nano-hydroxyapatite (nHA) coating enhances the osteoinductive potential of BCP ceramics, making these scaffolds more suitable for bone tissue engineering applications. The aim of the present study was to determine the effects of reconstructing radius defects in rabbits using nHA-coated BCP ceramics seeded with mesenchymal stem cells (MSCs) and to compare the bone regeneration induced by different scaffolds. Radius defects were created in 20 New Zealand rabbits, which were divided into four groups by treatment: porous BCP ceramics (Group A), nHA-coated porous BCP ceramics (Group B), porous BCP ceramics seeded with rabbit MSCs (Group C), and nHA-coated porous BCP ceramics seeded with rabbit MSCs (Group D). After in vitro incubation, the cell/scaffold complexes were implanted into the defects. Twelve weeks after implantation, the specimens were examined macroscopically and histologically. Both the nHA coating and seeding with MSCs enhanced the formation of new bone tissue in the BCP ceramics, though the osteoinductive potential of the scaffolds with MSCs was greater than that of the nHA-coated scaffolds. Notably, the combination of nHA coating and MSCs significantly improved the bone regeneration capability of the BCP ceramics. Thus, MSCs seeded into porous BCP ceramics coated with nHA may be an effective bone substitute to reconstruct bone defects in the clinic.

  19. Bone marrow culture

    MedlinePlus

    ... There may be some bleeding at the puncture site. More serious risks, such as serious bleeding or infection, are very rare. Alternative Names Culture - bone marrow Images Bone marrow aspiration References ...

  20. Bone fracture repair - slideshow

    MedlinePlus

    ... page: //medlineplus.gov/ency/presentations/100077.htm Bone fracture repair - series—Indications To use the sharing features ... Go to slide 4 out of 4 Overview Fractures of the bones are classified in a number ...

  1. Smoking and Bone Health

    MedlinePlus

    ... Management Strategies Resources For Your Information Facts About Osteoporosis Osteoporosis is a condition in which bones weaken ... adopt new habits for healthy bones. Smoking and Osteoporosis Cigarette smoking was first identified as a risk ...

  2. Surface Functionalization of Orthopedic Titanium Implants with Bone Sialoprotein.

    PubMed

    Baranowski, Andreas; Klein, Anja; Ritz, Ulrike; Ackermann, Angelika; Anthonissen, Joris; Kaufmann, Kerstin B; Brendel, Christian; Götz, Hermann; Rommens, Pol M; Hofmann, Alexander

    2016-01-01

    Orthopedic implant failure due to aseptic loosening and mechanical instability remains a major problem in total joint replacement. Improving osseointegration at the bone-implant interface may reduce micromotion and loosening. Bone sialoprotein (BSP) has been shown to enhance bone formation when coated onto titanium femoral implants and in rat calvarial defect models. However, the most appropriate method of BSP coating, the necessary level of BSP coating, and the effect of BSP coating on cell behavior remain largely unknown. In this study, BSP was covalently coupled to titanium surfaces via an aminosilane linker (APTES), and its properties were compared to BSP applied to titanium via physisorption and untreated titanium. Cell functions were examined using primary human osteoblasts (hOBs) and L929 mouse fibroblasts. Gene expression of specific bone turnover markers at the RNA level was detected at different intervals. Cell adhesion to titanium surfaces treated with BSP via physisorption was not significantly different from that of untreated titanium at any time point, whereas BSP application via covalent coupling caused reduced cell adhesion during the first few hours in culture. Cell migration was increased on titanium disks that were treated with higher concentrations of BSP solution, independent of the coating method. During the early phases of hOB proliferation, a suppressive effect of BSP was observed independent of its concentration, particularly when BSP was applied to the titanium surface via physisorption. Although alkaline phosphatase activity was reduced in the BSP-coated titanium groups after 4 days in culture, increased calcium deposition was observed after 21 days. In particular, the gene expression level of RUNX2 was upregulated by BSP. The increase in calcium deposition and the stimulation of cell differentiation induced by BSP highlight its potential as a surface modifier that could enhance the osseointegration of orthopedic implants. Both

  3. Surface Functionalization of Orthopedic Titanium Implants with Bone Sialoprotein

    PubMed Central

    Ritz, Ulrike; Ackermann, Angelika; Anthonissen, Joris; Kaufmann, Kerstin B.; Brendel, Christian; Götz, Hermann; Rommens, Pol M.; Hofmann, Alexander

    2016-01-01

    Orthopedic implant failure due to aseptic loosening and mechanical instability remains a major problem in total joint replacement. Improving osseointegration at the bone-implant interface may reduce micromotion and loosening. Bone sialoprotein (BSP) has been shown to enhance bone formation when coated onto titanium femoral implants and in rat calvarial defect models. However, the most appropriate method of BSP coating, the necessary level of BSP coating, and the effect of BSP coating on cell behavior remain largely unknown. In this study, BSP was covalently coupled to titanium surfaces via an aminosilane linker (APTES), and its properties were compared to BSP applied to titanium via physisorption and untreated titanium. Cell functions were examined using primary human osteoblasts (hOBs) and L929 mouse fibroblasts. Gene expression of specific bone turnover markers at the RNA level was detected at different intervals. Cell adhesion to titanium surfaces treated with BSP via physisorption was not significantly different from that of untreated titanium at any time point, whereas BSP application via covalent coupling caused reduced cell adhesion during the first few hours in culture. Cell migration was increased on titanium disks that were treated with higher concentrations of BSP solution, independent of the coating method. During the early phases of hOB proliferation, a suppressive effect of BSP was observed independent of its concentration, particularly when BSP was applied to the titanium surface via physisorption. Although alkaline phosphatase activity was reduced in the BSP-coated titanium groups after 4 days in culture, increased calcium deposition was observed after 21 days. In particular, the gene expression level of RUNX2 was upregulated by BSP. The increase in calcium deposition and the stimulation of cell differentiation induced by BSP highlight its potential as a surface modifier that could enhance the osseointegration of orthopedic implants. Both

  4. Mechanical stability of two-step chemically deposited hydroxyapatite coating on Ti substrate: effects of various surface pretreatments.

    PubMed

    Zavgorodniy, Alexander V; Borrero-López, Oscar; Hoffman, Mark; LeGeros, Racquel Z; Rohanizadeh, Ramin

    2011-10-01

    The success of implants in orthopaedic and dental load-bearing applications crucially depends on the initial biological fixation of implants in surrounding bone tissues. Using hydroxyapatite (HA) coating on Ti implant as carrier for bone morphogenetic proteins (BMPs) may promote the osteointegration of implants; therefore, reduce the risk of implant failure. The goal of this study was to develop an HA coating method in conditions allowing the incorporation of protein-based drugs into the coating materials, while achieving a mechanical stable coating on Ti implant. HA coatings were deposited on six different groups of Ti surfaces: control (no pretreatment), pretreated with alkali, acid, heat at 800°C, grit blasted with Al₂O₃, and grit blasted followed by heat treatment. HA coating was prepared using a two-step procedure. First step was the chemical deposition of a monetite coating on Ti substrate in acidic condition at 75°C and the second step was the hydrolysis of the monetite coating to HA. Coatings were characterized by scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The roughness of substrates and coatings was measured using profilometry technique. The mechanical stability of the coatings deposited on the pretreated substrates was assessed using scratch test. The coatings deposited on the grit-blasted Ti surface demonstrated superior adhesive properties with critical shearing stress 131.6 ± 0.2 MPa.

  5. Stimulation of bone healing by sustained bone morphogenetic protein 2 (BMP-2) delivery.

    PubMed

    Faßbender, Mirja; Minkwitz, Susann; Strobel, Catrin; Schmidmaier, Gerhard; Wildemann, Britt

    2014-05-14

    The aim of the study was to investigate the effect of a sustained release of bone morphogenetic protein2 (BMP-2) incorporated in a polymeric implant coating on bone healing. In vitro analysis revealed a sustained, but incomplete BMP-2 release until Day 42. For the in vivo study, the rat tibia osteotomy was stabilized either with control or BMP-2 coated wires, and the healing progress was followed by micro computed tomography (µCT), biomechanical testing and histology at Days 10, 28, 42 and 84. MicroCT showed an accelerated formation of mineralized callus, as well as remodeling and an increase of mineralized/total callus volume (p=0.021) at Day 42 in the BMP-2 group compared to the control. Histology revealed an increased callus mineralization at Days 42 and 84 (p=0.006) with reduced cartilage at Day 84 (p=0.004) in the BMP-2 group. Biomechanical stiffness was significantly higher in the BMP-2 group (p=0.045) at Day 42. In summary, bone healing was enhanced after sustained BMP-2 application compared to the control. Using the same drug delivery system, but a burst release of BMP-2, a previous published study showed a similar positive effect on bone healing. Distinct differences in the healing outcome might be explained due to the different BMP release kinetics and dosages. However, further studies are necessary to adapt the optimal release profiles to physiological mechanisms.

  6. The Future of Biologic Coatings for Orthopaedic Implants

    PubMed Central

    Goodman, Stuart B.; Yao, Zhenyu; Keeney, Michael; Yang, Fan

    2013-01-01

    Implants are widely used for othopaedic applications such as fixing fractures, repairing nonunions, obtaining a joint arthrodesis, total joint arthroplasty, spinal reconstruction, and soft tissue anchorage. Previously, orthopaedic implants were designed simply as mechanical devices; the biological aspects of the implant were a byproduct of stable internal/external fixation of the device to the surrounding bone or soft tissue. More recently, biologic coatings have been incorporated into orthopaedic implants in order to modulate the surrounding biological environment. This opinion article reviews current and potential future use of biologic coatings for orthopaedic implants to facilitate osseointegration and mitigate possible adverse tissue responses including the foreign body reaction and implant infection. While many of these coatings are still in the preclinical testing stage, bioengineers, material scientists and surgeons continue to explore surface coatings as a means of improving clinical outcome of patients undergoing orthopaedic surgery. PMID:23391496

  7. Medicines and Bone Loss

    MedlinePlus

    ... studies also show that drinking a lot of alcohol might weaken bones. Questions to ask your doctor • Do any of my medicines cause bone loss? • Are there different medicines I can take? • Do I need a bone density test? • What should I do to protect my ...

  8. Temporal bone meningiomas.

    PubMed

    Hooper, R; Siu, K; Cousins, V

    1990-10-01

    Meningiomas should be considered in the differential diagnosis of space-occupying lesions of the temporal bone. Five cases of meningiomas of the temporal bone are described and the literature reviewed. These tumours may stimulate Schwannomas and glomus tumours in their presentation and radiological findings. The tumours were managed by combining standard neurosurgical approaches with temporal bone and skull base techniques.

  9. Coatings for graphite fibers

    NASA Technical Reports Server (NTRS)

    Galasso, F. S.; Scola, D. A.; Veltri, R. D.

    1980-01-01

    Graphite fibers released from composites during burning or an explosion caused shorting of electrical and electronic equipment. Silicon carbide, silica, silicon nitride and boron nitride were coated on graphite fibers to increase their electrical resistances. Resistances as high as three orders of magnitude higher than uncoated fiber were attained without any significant degradation of the substrate fiber. An organo-silicone approach to produce coated fibers with high electrical resistance was also used. Celion 6000 graphite fibers were coated with an organo-silicone compound, followed by hydrolysis and pyrolysis of the coating to a silica-like material. The shear and flexural strengths of composites made from high electrically resistant fibers were considerably lower than the shear and flexural strengths of composites made from the lower electrically resistant fibers. The lower shear strengths of the composites indicated that the coatings on these fibers were weaker than the coating on the fibers which were pyrolyzed at higher temperature.

  10. Enhanced anti-tumor activity and safety profile of targeted nano-scaled HPMA copolymer-alendronate-TNP-470 conjugate in the treatment of bone malignances

    PubMed Central

    Segal, Ehud; Pan, Huaizhong; Benayoun, Liat; Kopečková, Pavla; Shaked, Yuval; Kopeček, Jindčrich; Satchi-Fainaro, Ronit

    2015-01-01

    Bone neoplasms, such as osteosarcoma, exhibit a propensity for systemic metastases resulting in adverse clinical outcome. Traditional treatment consisting of aggressive chemotherapy combined with surgical resection, has been the mainstay of these malignances. Therefore, bone-targeted non-toxic therapies are required. We previously conjugated the aminobisphosphonate alendronate (ALN), and the potent anti-angiogenic agent TNP-470 with N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer. HPMA copolymer-ALN-TNP-470 conjugate exhibited improved anti-angiogenic and anti-tumor activity compared with the combination of free ALN and TNP-470 when evaluated in a xenogeneic model of human osteosarcoma. The immune system has major effect on toxicology studies and on tumor progression. Therefore, in this manuscript we examined the safety and efficacy profiles of the conjugate using murine osteosarcoma syngeneic model. Toxicity and efficacy evaluation revealed superior anti-tumor activity and decreased organ-related toxicities of the conjugate compared with the combination of free ALN plus TNP-470. Finally, comparative anti-angiogenic activity and specificity studies, using surrogate biomarkers of circulating endothelial cells (CEC), highlighted the advantage of the conjugate over the free agents. The therapeutic platform described here may have clinical translational relevance for the treatment of bone-related angiogenesis-dependent malignances. PMID:21429572

  11. Functionally graded bioactive coatings: From fabrication to testing

    NASA Astrophysics Data System (ADS)

    Foppiano, Silvia

    Every year about half a million Americans undergo total joint replacement surgery of some kind. This number is expected to steadily increase in the future. About 20% of these patients will need a revision surgery because of implant failure, with a significant increase in health care cost. Current implant materials for load bearing applications must be strong enough to support the loads involved in daily activities, and bioinert, to limit reactivity in the body that may cause inflammatory and other adverse reactions. Metal alloys are typically used as materials for load bearing implants and rely on mechanical interlocking to achieve fixation which can be improved by using bone cements. To improve implant osteointegration, metal implants have been coated with a bone-like mineral: hydroxyapatite (HA). The plasma spray technique is commonly used to apply the HA coating. Such implants do not require the use of bone cement. Plasma sprayed HA coated implants are FDA approved and currently on the market, but their properties are not reproducible or reliable. Thus, coating delamination can occur. Our research group developed a novel family of bioactive glasses which were enameled onto titanium alloy using a functionally graded approach. We stratified the coating with different glass compositions to fulfill different functions. We coupled a first glass layer, with a good CTE match to the alloy, with a second layer of bioactive glass obtaining a functionally graded bioactive coating (FGC). In this thesis for the first time the cytocompatibility of novel bioactive glasses, and their functionally graded coatings on Ti6Al4V, was studied with an in vitro bone model (MC3T3-E1.4 mouse preosteblast cells). The novel bioactive glasses are cytocompatible and no compositional change is required. The fabrication process is reproducible, introduces a small (average 6 vol%) amount of crystallization, which does not significantly affect bioactivity in SBF as tested. The coatings are

  12. Electrospark deposition coatings

    NASA Astrophysics Data System (ADS)

    Sheely, W. F.

    1986-11-01

    Hard surfacing for wear resistant and low-friction coatings has been improved by means of advances in the computer controls in electronic circuitry of the electrospark deposition (ESD) process. coatings of nearly any electrically conductive metal alloy or cermet can be deposited on conductive materials. Thickness is usually two mils or less, but can be as high as 10 mils. ESD coatings can quadrupole cutting tool life.

  13. Optical coating in space

    NASA Technical Reports Server (NTRS)

    Bunner, A. N.

    1983-01-01

    A technological appraisal of the steps required to approach the goal of in-situ optical coating, cleaning and re-coating the optical elements of a remote telescope in space is reported. Emphasis is placed on the high ultraviolet throughput that a telescope using bare aluminum mirrors would offer. A preliminary design is suggested for an Orbital Coating Laboratory to answer basic technical questions.

  14. Electrospark deposition coatings

    SciTech Connect

    Sheely, W.F.

    1986-11-19

    Hard surfacing for wear resistant and low-friction coatings has been improved by means of advances in the computer controls in electronic circuitry of the electrospark deposition (ESD) process. coatings of nearly any electrically conductive metal alloy or cermet can be deposited on conductive materials. Thickness is usually two mils or less, but can be as high as 10 mils. ESD coatings can quadrupole cutting tool life. (DLC)

  15. Solar selective absorption coatings

    DOEpatents

    Mahoney, Alan R.; Reed, Scott T.; Ashley, Carol S.; Martinez, F. Edward

    2003-10-14

    A new class of solar selective absorption coatings are disclosed. These coatings comprise a structured metallic overlayer such that the overlayer has a sub-micron structure designed to efficiently absorb solar radiation, while retaining low thermal emissivity for infrared thermal radiation. A sol-gel layer protects the structured metallic overlayer from mechanical, thermal, and environmental degradation. Processes for producing such solar selective absorption coatings are also disclosed.

  16. Solar selective absorption coatings

    DOEpatents

    Mahoney, Alan R.; Reed, Scott T.; Ashley, Carol S.; Martinez, F. Edward

    2004-08-31

    A new class of solar selective absorption coatings are disclosed. These coatings comprise a structured metallic overlayer such that the overlayer has a sub-micron structure designed to efficiently absorb solar radiation, while retaining low thermal emissivity for infrared thermal radiation. A sol-gel layer protects the structured metallic overlayer from mechanical, thermal, and environmental degradation. Processes for producing such solar selective absorption coatings are also disclosed.

  17. Ultrasonic elasticity determination of 45S5 Bioglass(®)-based scaffolds: influence of polymer coating and crosslinking treatment.

    PubMed

    Li, Wei; Pastrama, Maria-Ioana; Ding, Yaping; Zheng, Kai; Hellmich, Christian; Boccaccini, Aldo R

    2014-12-01

    Highly porous 45S5 Bioglass(®)-based scaffolds with interconnected pore structure are promising candidates for bone tissue engineering due to their bioactivity, biocompatibility, osteogenic and angiogenic effects. In the present study, to ensure the mechanical competence of the 45S5 Bioglass(®)-based scaffolds, their stiffness was adjusted by applying polymer coatings and further crosslinking treatment. A non-destructive ultrasonic technique was used to determine the stiffness of the scaffolds. The stiffness of uncoated scaffolds was shown to increase by applying polymer coatings, and a further increase was achieved by crosslinking the used polymer coatings. All uncoated and polymer-coated scaffolds were confirmed to exhibit stiffness values in the range of reported values in the literature for cancellous bone. A statistical evaluation of combined multiscale ultrasound-nanoindentation measurements indicated that the stiffness of the coated scaffold is directly dependent on the stiffness of the polymer coating.

  18. Method of coating a substrate with a calcium phosphate compound

    DOEpatents

    Gao, Yufei; Campbell, Allison A.

    2000-01-01

    The present invention is a method of coating a substrate with a calcium phosphate compound using plasma enhanced MOCVD. The substrate is a solid material that may be porous or non-porous, including but not limited to metal, ceramic, glass and combinations thereof. The coated substrate is preferably used as an implant, including but not limited to orthopaedic, dental and combinations thereof. Calcium phosphate compound includes but is not limited to tricalcium phosphate (TCP), hydroxyapatite (HA) and combinations thereof. TCP is preferred on a titanium implant when implant resorbability is desired. HA is preferred when the bone bonding of new bone tissue into the structure of the implant is desired. Either or both of TCP and/or HA coated implants may be placed into a solution with an agent selected from the group of protein, antibiotic, antimicrobial, growth factor and combinations thereof that can be adsorbed into the coating before implantation. Once implanted, the release of TCP will also release the agent to improve growth of new bone tissues and/or to prevent infection.

  19. Embroidered and surface coated polycaprolactone-co-lactide scaffolds

    PubMed Central

    Rentsch, Barbe; Bernhardt, Ricardo; Scharnweber, Dieter; Schneiders, Wolfgang; Rammelt, Stefan; Rentsch, Claudia

    2012-01-01

    Tissue engineering and regenerative techniques targeting bone include a broad range of strategies and approaches to repair, augment, replace or regenerate bone tissue. Investigations that are aimed at optimization of these strategies until clinical translation require control of systemic factors as well as modification of a broad range of key parameters. This article reviews a possible strategy using a tissue engineering approach and systematically describes a series of experiments evaluating the properties of an embroidered and surface coated polycaprolactone-co-lactide scaffold being considered as bone graft substitute for large bone defects. The scaffold design and fabrication, the scaffolds properties, as well as its surface modification and their influence in vitro are evaluated, followed by in vivo analysis of the scaffolds using orthotopic implantation models in small and large animals. PMID:23507867

  20. Effects of various drilling parameters on bone during implantology: An in vitro experimental study.

    PubMed

    Karaca, Faruk; Aksakal, Bunyamin

    2013-01-01

    Due to temperature increase during bone drilling, bone necrosis is likely to occur. To minimize bone tissue damage during drilling, a detailed in vitro experimental study by using fresh calf cortical bones has been performed with various combined drilling parameters, such as: drilling environment, drill diameter, drill speed, drill force, feed-rate and drill coating. Bone temperatures at the drilling sites were recorded with high accuracy using multi-thermocouples mounted around the tibial diaphyseal cortex. It was shown that temperatures increased with increased drill speeds. It also decreased with a higher feed-rate and drill force. It was also observed that TiBN coated drills caused higher temperatures in the bone than the uncoated drills and the temperatures increased with larger drill diameters. Although the influence of Simulated Body Fluid (SBF) on rising temperatures during drilling was higher for the TiBN coated drills, it was observed that these drills caused more damage to the bone structure. In order to minimize or avoid bone defects and necrosis, orthopaedic surgeons should consider the optimum drilling parameters.

  1. Zinc phosphate conversion coatings

    DOEpatents

    Sugama, T.

    1997-02-18

    Zinc phosphate conversion coatings for producing metals which exhibit enhanced corrosion prevention characteristics are prepared by the addition of a transition-metal-compound promoter comprising a manganese, iron, cobalt, nickel, or copper compound and an electrolyte such as polyacrylic acid, polymethacrylic acid, polyitaconic acid and poly-L-glutamic acid to a phosphating solution. These coatings are further improved by the incorporation of Fe ions. Thermal treatment of zinc phosphate coatings to generate {alpha}-phase anhydrous zinc phosphate improves the corrosion prevention qualities of the resulting coated metal. 33 figs.

  2. Zinc phosphate conversion coatings

    DOEpatents

    Sugama, Toshifumi

    1997-01-01

    Zinc phosphate conversion coatings for producing metals which exhibit enhanced corrosion prevention characteristics are prepared by the addition of a transition-metal-compound promoter comprising a manganese, iron, cobalt, nickel, or copper compound and an electrolyte such as polyacrylic acid, polymethacrylic acid, polyitaconic acid and poly-L-glutamic acid to a phosphating solution. These coatings are further improved by the incorporation of Fe ions. Thermal treatment of zinc phosphate coatings to generate .alpha.-phase anhydrous zinc phosphate improves the corrosion prevention qualities of the resulting coated metal.

  3. Aircraft surface coatings

    NASA Technical Reports Server (NTRS)

    1983-01-01

    A series of studies in which films and liquid spray-on materials were evaluated in the laboratory for transport aircraft external surface coatings are summarized. Elastomeric polyurethanes were found to best meet requirements. Two commercially available products, CAAPCO B-274 and Chemglaze M313, were subjected to further laboratory testing, airline service evaluations, and drag-measurement flight tests. It was found that these coatings were compatible with the severe operating environment of airlines and that coatings reduced airplane drag. An economic analysis indicated significant dollar benefits to airlines from application of the coatings.

  4. Coatings for Graphite Fibers

    NASA Technical Reports Server (NTRS)

    Galasso, F. S.; Scola, D. A.; Veltri, R. D.

    1980-01-01

    Several approaches for applying high resistance coatings continuously to graphite yarn were investigated. Two of the most promising approaches involved (1) chemically vapor depositing (CVD) SiC coatings on the surface of the fiber followed by oxidation, and (2) drawing the graphite yarn through an organo-silicone solution followed by heat treatments. In both methods, coated fibers were obtained which exhibited increased electrical resistances over untreated fibers and which were not degraded. This work was conducted in a previous program. In this program, the continuous CVD SiC coating process used on HTS fiber was extended to the coating of HMS, Celion 6000, Celion 12000 and T-300 graphite fiber. Electrical resistances three order of magnitude greater than the uncoated fiber were measured with no significant degradation of the fiber strength. Graphite fibers coated with CVD Si3N4 and BN had resistances greater than 10(exp 6) ohm/cm. Lower pyrolysis temperatures were used in preparing the silica-like coatings also resulting in resistances as high as three orders of magnitude higher than the uncoated fiber. The epoxy matrix composites prepared using these coated fibers had low shear strengths indicating that the coatings were weak.

  5. Oxide coating development

    SciTech Connect

    Stinton, D.P.

    1995-06-01

    Monolithic SiC heat exchangers and fiber-reinforced SiC-matrix composite heat exchangers and filters are susceptible to corrosion by alkali metals at elevated temperatures. Protective coatings are currently being developed to isolate the SiC materials from the corrodants. Unfortunately, these coatings typically crack and spall when applied to SiC substrates. The purpose of this task is to determine the feasibility of using a compliant material between the protective coating and the substrate. The low-modulus compliant layer could absorb stresses and eliminate cracking and spalling of the protective coatings.

  6. Local bisphosphonate release versus hydroxyapatite coating for stainless steel screw fixation in rat tibiae.

    PubMed

    Agholme, F; Andersson, T; Tengvall, P; Aspenberg, P

    2012-03-01

    Implant fixation in bone can be improved by a coating that delivers bisphosphonates locally, or by a hydroxyapatite (HA) coating. In this study, we compared these different types of coatings. For mechanical testing, 30 rats were assigned into three groups, and similar screws were implanted bilaterally in the proximal tibiae. The rats received screws that were either uncoated, coated with nano-crystalline hydroxyapatite or coated with a bisphosphonate releasing protein matrix. After 4 weeks, one screw was subjected to pull-out testing, and the contra-lateral one to torsion testing. For morphology, 30 rats were assigned to similar treatment groups, but received only one screw each. Bisphosphonates enhanced the pull-out force by 41% (P = 0.02) compared to controls, HA increased the pull-out force although not significantly. Conversely, HA increased the maximal torque by 64% (P = 0.02). Morphometry showed higher bone volume around bisphosphonate screws in comparison to HA-coated screws (P < 0.001) and controls (P < 0.001). The results suggest that bisphosphonates improve fixation by increasing the amount of surrounding bone, whereas HA mainly improves bone to implant attachment.

  7. Method for fusing bone

    DOEpatents

    Mourant, Judith R.; Anderson, Gerhard D.; Bigio, Irving J.; Johnson, Tamara M.

    1996-01-01

    Method for fusing bone. The present invention is a method for joining hard tissue which includes chemically removing the mineral matrix from a thin layer of the surfaces to be joined, placing the two bones together, and heating the joint using electromagnetic radiation. The goal of the method is not to produce a full-strength weld of, for example, a cortical bone of the tibia, but rather to produce a weld of sufficient strength to hold the bone halves in registration while either external fixative devices are applied to stabilize the bone segments, or normal healing processes restore full strength to the tibia.

  8. Rotary ultrasonic bone drilling: Improved pullout strength and reduced damage.

    PubMed

    Gupta, Vishal; Pandey, Pulak M; Silberschmidt, Vadim V

    2017-03-01

    Bone drilling is one of the most common operations used to repair fractured parts of bones. During a bone drilling process, microcracks are generated on the inner surface of the drilled holes that can detrimentally affect osteosynthesis and healing. This study focuses on the investigation of microcracks and pullout strength of cortical-bone screws in drilled holes. It compares conventional surgical bone drilling (CSBD) with rotary ultrasonic bone drilling (RUBD), a novel approach employing ultrasonic vibration with a diamond-coated hollow tool. Both techniques were used to drill holes in porcine bones in an in-vitro study. Scanning electron microscopy was used to observe microcracks and surface morphology. The results obtained showed a significant decrease in the number and dimensions of microcracks generated on the inner surface of drilled holes with the RUBD process in comparison to CSBD. It was also observed that a higher rotational speed and a lower feed rate resulted in lower damage, i.e. fewer microcracks. Biomechanical axial pullout strength of a cortical bone screw inserted into a hole drilled with RUBD was found to be much higher (55-385%) than that for CSBD.

  9. Poly(vinyl alcohol) hydrogel coatings with tunable surface exposure of hydroxyapatite

    PubMed Central

    Moreau, David; Villain, Arthur; Ku, David N; Corté, Laurent

    2014-01-01

    Insufficient bone anchoring is a major limitation of artificial substitutes for connective osteoarticular tissues. The use of coatings containing osseoconductive ceramic particles is one of the actively explored strategies to improve osseointegration and strengthen the bone-implant interface for general tissue engineering. Our hypothesis is that hydroxyapatite (HA) particles can be coated robustly on specific assemblies of PVA hydrogel fibers for the potential anchoring of ligament replacements. A simple dip-coating method is described to produce composite coatings made of microscopic hydroxyapatite (HA) particles dispersed in a poly(vinyl alcohol) (PVA) matrix. The materials are compatible with the requirements for implant Good Manufacturing Practices. They are applied to coat bundles of PVA hydrogel fibers used for the development of ligament implants. By means of optical and electronic microscopy, we show that the coating thickness and surface state can be adjusted by varying the composition of the dipping solution. Quantitative analysis based on backscattered electron microscopy show that the exposure of HA at the coating surface can be tuned from 0 to over 55% by decreasing the weight ratio of PVA over HA from 0.4 to 0.1. Abrasion experiments simulating bone-implant contact illustrate how the coating cohesion and wear resistance increase by increasing the content of PVA relative to HA. Using pullout experiments, we find that these coatings adhere well to the fiber bundles and detach by propagation of a crack inside the coating. These results provide a guide to select coated implants for anchoring artificial ligaments. PMID:25482413

  10. Biological characterization of a new silicon based coating developed for dental implants.

    PubMed

    Martínez-Ibáñez, M; Juan-Díaz, M J; Lara-Saez, I; Coso, A; Franco, J; Gurruchaga, M; Suay Antón, J; Goñi, Isabel

    2016-04-01

    Taking into account the influence of Si in osteoblast cell proliferation, a series of sol-gel derived silicon based coating was prepared by controlling the process parameters and varying the different Si-alkoxide precursors molar rate in order to obtain materials able to release Si compounds. For this purpose, methyltrimethoxysilane (MTMOS) and tetraethyl orthosilicate (TEOS) were hydrolysed together and the sol obtained was used to dip-coat the different substrates. The silicon release ability of the coatings was tested finding that it was dependent on the TEOS precursor content, reaching a Si amount value around ninefolds higher for coatings with TEOS than for the pure MTMOS material. To test the effect of this released Si, the in vitro performance of developed coatings was tested with human adipose mesenchymal stem cells finding a significantly higher proliferation and mineralization on the coating with the higher TEOS content. For in vivo evaluation of the biocompatibility, coated implants were placed in the tibia of the rabbit and a histological analysis was performed. The evaluation of parameters such as the bone marrow state, the presence of giant cells and the fibrous capsule proved the biocompatibility of the developed coatings. Furthermore, coated implants seemed to produce a qualitatively higher osteoblastic activity and a higher number of bone spicules than the control (uncoated commercial SLA titanium dental implant).

  11. Rapid coating of AZ31 magnesium alloy with calcium deficient hydroxyapatite using microwave energy.

    PubMed

    Ren, Yufu; Zhou, Huan; Nabiyouni, Maryam; Bhaduri, Sarit B

    2015-04-01

    Due to their unique biodegradability, magnesium alloys have been recognized as suitable metallic implant materials for degradable bone implants and bioresorbable cardiovascular stents. However, the extremely high degradation rate of magnesium alloys in physiological environment has restricted its practical application. This paper reports the use of a novel microwave assisted coating technology to improve the in vitro corrosion resistance and biocompatibility of Mg alloy AZ31. Results indicate that a dense calcium deficient hydroxyapatite (CDHA) layer was uniformly coated on a AZ31 substrate in less than 10min. Weight loss measurement and SEM were used to evaluate corrosion behaviors in vitro of coated samples and of non-coated samples. It was seen that CDHA coatings remarkably reduced the mass loss of AZ31 alloy after 7days of immersion in SBF. In addition, the prompt precipitation of bone-like apatite layer on the sample surface during immersion demonstrated a good bioactivity of the CDHA coatings. Proliferation of osteoblast cells was promoted in 5days of incubation, which indicated that the CDHA coatings could improve the cytocompatibility of the AZ31 alloy. All the results suggest that the CDHA coatings, serving as a protective layer, can enhance the corrosion resistance and biological response of magnesium alloys. Furthermore, this microwave assisted coating technology could be a promising method for rapid surface modification of biomedical materials.

  12. Hydroxyapatite coatings with oriented nanoplate and nanorod arrays: Fabrication, morphology, cytocompatibility and osteogenic differentiation.

    PubMed

    Chen, Wei; Tian, Bo; Lei, Yong; Ke, Qin-Fei; Zhu, Zhen-An; Guo, Ya-Ping

    2016-10-01

    Hydroxyapatite (HA) crystals exhibit rod-like shape with c-axis orientation and plate-like shape with a(b)-axis orientation in vertebrate bones and tooth enamel surfaces, respectively. Herein, we report the synthesis of HA coatings with the oriented nanorod arrays (RHACs) and HA coatings with oriented nanoplate arrays (PHACs) by using bioglass coatings as sacrificial templates. After soaking in simulated body fluid (SBF) at 120°C, the bioglass coatings are hydrothermally converted into the HA coatings via a dissolution-precipitation reaction. If the Ca/P ratios in SBF are 2.50 and 1.25, the HA crystals on the coatings are oriented nanorod arrays and oriented nanoplate arrays, respectively. Moreover, the bioglass coatings are treated with SBF at 37°C, plate-like HA coatings with a low crystallinity (SHACs) are prepared. As compared with the Ti6Al4V and SHACs, the human bone marrow stromal cells (hBMSCs) on the RHACs and PHACs have better cell adhesion, spreading, proliferation and osteogenic differentiation because of their moderately hydrophilic surfaces and similar chemical composition, morphology and crystal orientation to human hard tissues. Notably, the morphologies of HA crystals have no obvious effects on cytocompatibility and osteogenic differentiation. Hence, the HA coatings with oriented nanoplate arrays or oriented nanorod arrays have a great potential for orthopedic applications.

  13. Hematopoiesis on cellulose ester membranes. XI. Induction of new bone and a hematopoietic microenvironment by matrix factors secreted by marrow stromal cells.

    PubMed

    Knospe, W H; Husseini, S G; Fried, W

    1989-07-01

    Cellulose ester membranes (CEM) were coated with stromal cells from bone marrow (BM) or bone and implanted intraperitoneally (IP) in CAF1 mice for intervals of 1 to 6 months. Previous studies indicated that matrix factors [glycoproteins (GPs), proteoglycans (PGs), and glycosaminoglycans (GAGs)] were secreted by the regenerating stromal cells and adsorbed by the CEM. After 1 to 6 months, the CEMs were removed, scraped free of adherent cells, and irradiated in vitro with 40 Gy. The scraped and irradiated CEMs were then reimplanted IP or subcutaneously (SC) for periods of 1 to 6 months in secondary syngeneic murine hosts. They were then removed for histologic study. CEMs reimplanted in SC sites developed bone and hematopoiesis as early as 1 month after implantation. Maximum hematopoiesis and bone formation was observed after 3 months. CEMs coated during the initial implantation with bone-derived stromal cells contained more bone and hematopoietic cells than did CEMs coated with marrow-derived stromal cells after SC implementation. Neither the CEMs coated with bone stromal cells nor those coated with marrow stromal cells developed new bone or trilineal hematopoiesis after being implanted IP. A few CEMs contained small foci of granulopoiesis only. We conclude that noncellular matrix substances deposited on CEMs by bone, and to a lesser degree by marrow cells, can induce prestromal cells in the SC tissues to produce a microenvironment suitable for trilineal hematopoiesis.

  14. Bone regeneration in dentistry

    PubMed Central

    Tonelli, Paolo; Duvina, Marco; Barbato, Luigi; Biondi, Eleonora; Nuti, Niccolò; Brancato, Leila; Rose, Giovanna Delle

    2011-01-01

    Summary The edentulism of the jaws and the periodontal disease represent conditions that frequently leads to disruption of the alveolar bone. The loss of the tooth and of its bone of support lead to the creation of crestal defects or situation of maxillary atrophy. The restoration of a functional condition involves the use of endosseous implants who require adequate bone volume, to deal with the masticatory load. In such situations the bone need to be regenerated, taking advantage of the biological principles of osteogenesis, osteoinduction and osteoconduction. Several techniques combine these principles with different results, due to the condition of the bone base on which we operate changes, the surgical technique that we use, and finally for the bone metabolic conditions of the patient who can be in a state of systemic osteopenia or osteoporosis; these can also affect the result of jaw bone reconstruction. PMID:22461825

  15. Nanomaterials and bone regeneration

    PubMed Central

    Gong, Tao; Xie, Jing; Liao, Jinfeng; Zhang, Tao; Lin, Shiyu; Lin, Yunfeng

    2015-01-01

    The worldwide incidence of bone disorders and conditions has been increasing. Bone is a nanomaterials composed of organic (mainly collagen) and inorganic (mainly nano-hydroxyapatite) components, with a hierarchical structure ranging from nanoscale to macroscale. In consideration of the serious limitation in traditional therapies, nanomaterials provide some new strategy in bone regeneration. Nanostructured scaffolds provide a closer structural support approximation to native bone architecture for the cells and regulate cell proliferation, differentiation, and migration, which results in the formation of functional tissues. In this article, we focused on reviewing the classification and design of nanostructured materials and nanocarrier materials for bone regeneration, their cell interaction properties, and their application in bone tissue engineering and regeneration. Furthermore, some new challenges about the future research on the application of nanomaterials for bone regeneration are described in the conclusion and perspectives part. PMID:26558141

  16. Bone scintiscanning updated.

    PubMed

    Lentle, B C; Russell, A S; Percy, J S; Scott, J R; Jackson, F I

    1976-03-01

    Use of modern materials and methods has given bone scintiscanning a larger role in clinical medicine, The safety and ready availability of newer agents have led to its greater use in investigating both benign and malignant disease of bone and joint. Present evidence suggests that abnormal accumulation of 99mTc-polyphosphate and its analogues results from ionic deposition at crystal surfaces in immature bone, this process being facilitated by an increase in bone vascularity. There is, also, a component of matrix localization. These factors are in keeping with the concept that abnormal scintiscan sites represent areas of increased osteoblastic activity, although this may be an oversimplification. Increasing evidence shows that the bone scintiscan is more sensitive than conventional radiography in detecting focal disease of bone, and its ability to reflect the immediate status of bone further complements radiographic findings. The main limitation of this method relates to nonspecificity of the results obtained.

  17. Calcium and bone disease

    PubMed Central

    Blair, Harry C.; Robinson, Lisa J.; Huang, Christopher L.-H.; Sun, Li; Friedman, Peter A.; Schlesinger, Paul H.; Zaidi, Mone

    2013-01-01

    Calcium transport and calcium signaling are of basic importance in bone cells. Bone is the major store of calcium and a key regulatory organ for calcium homeostasis. Bone, in major part, responds to calcium-dependent signals from the parathyroids and via vitamin D metabolites, although bone retains direct response to extracellular calcium if parathyroid regulation is lost. Improved understanding of calcium transporters and calcium-regulated cellular processes has resulted from analysis of genetic defects, including several defects with low or high bone mass. Osteoblasts deposit calcium by mechanisms including phosphate and calcium transport with alkalinization to absorb acid created by mineral deposition; cartilage calcium mineralization occurs by passive diffusion and phosphate production. Calcium mobilization by osteoclasts is mediated by acid secretion. Both bone forming and bone resorbing cells use calcium signals as regulators of differentiation and activity. This has been studied in more detail in osteoclasts, where both osteoclast differentiation and motility are regulated by calcium. PMID:21674636

  18. Bone morphogenetic proteins, cementogenesis, myoblastic stem cells and the induction of periodontal tissue regeneration.

    PubMed

    Ripamonti, Ugo; Petit, Jean-Claude

    2009-01-01

    'Bone: Formation by autoinduction', initiates by invocation of soluble molecular signals which, when combined to insoluble signals or substrata trigger the ripple-like cascade of bone differentiation by induction. The osteogenic proteins of the transforming growth factor-beta (TGF-beta) superfamily, the bone morphogenetic/osteogenic proteins (BMPs/OPs), and uniquely in the non-human primate Papio ursinus also the three mammalian TGF-beta isoforms, induce endochondral bone formation as recapitulation of embryonic development. The pleiotropic activities of the BMPs/OPs are vast and include the induction of periodontal tissue regeneration. Implantation of naturally derived highly purified osteogenic fractions after sequential adsorption/affinity and gel filtration chromatography in mandibular Class II furcation defects of P. ursinus induces cementogenesis as highly cellular collagenic cementoid attached to the exposed dentine with foci of nascent mineralization with inserted de novo generated Sharpey's fibres. Recombinant human osteogenic protein-1 (hOP-1) when implanted in Class II furcation defects of P. ursinus with surgically exposed dentine matrix preferentially initiates the induction of cementogenesis; on the other hand, hBMP-2 preferentially induces alveolar bone regeneration with mineralized bone covered by prominent osteoid seams. Long-term studies with gamma-irradiated 0.5 and 2.5mg hOP-1 per gram of xenogeneic bovine collagenous matrix induce the restitutio ad integrum of the periodontal tissues in furcation defects exposed by chronic periodontitis in P. ursinus. A challenging question for tissue engineering and regenerative medicine is whether the presence of molecularly different osteogenic proteins of the TGF-beta superfamily has a therapeutic significance. Mechanistically, the specificity of hOP-1 primarily initiating cementogenesis in periodontal defects is regulated by both the dentine extracellular matrix upon which responding cells attach and

  19. Marble Bone Disease: A Rare Bone Disorder

    PubMed Central

    Harinathbabu, Maheswari; Thillaigovindan, Ranjani; Prabhu, Geetha

    2015-01-01

    Osteopetrosis, or marble bone disease, is a rare skeletal disorder due to a defective function of the osteoclasts. This defect renders bones more susceptible to osteomyelitis due to decreased vascularity. This disorder is inherited as autosomal dominant and autosomal recessive. Healthcare professionals should urge these patients to maintain their oral health as well as general health, as this condition makes these patients more susceptible to frequent infections and fractures. This case report emphasizes the signs and symptoms of marble bone disease and presents clinical and radiographic findings.  PMID:26594603

  20. Combustion chemical vapor deposited coatings for thermal barrier coating systems

    SciTech Connect

    Hampikian, J.M.; Carter, W.B.

    1995-12-31

    The new deposition process, combustion chemical vapor deposition, shows a great deal of promise in the area of thermal barrier coating systems. This technique produces dense, adherent coatings, and does not require a reaction chamber. Coatings can therefore be applied in the open atmosphere. The process is potentially suitable for producing high quality CVD coatings for use as interlayers between the bond coat and thermal barrier coating, and/or as overlayers, on top of thermal barrier coatings. In this report, the evaluation of alumina and ceria coatings on a nickel-chromium alloy is described.

  1. The promising application of graphene oxide as coating materials in orthopedic implants: preparation, characterization and cell behavior.

    PubMed

    Zhao, Changhong; Lu, Xiuzhen; Zanden, Carl; Liu, Johan

    2015-02-10

    To investigate the potential application of graphene oxide (GO) in bone repair, this study is focused on the preparation, characterization and cell behavior of graphene oxide coatings on quartz substrata. GO coatings were prepared on the substrata using a modified dip-coating procedure. Atomic force microscopy (AFM), scanning electron microscopy (SEM) and Raman spectroscopy results demonstrated that the as-prepared coatings in this study were homogeneous and had an average thickness of ~67 nm. The rapid formation of a hydroxyapatite (HA) layer in the simulated body fluid (SBF) on GO coated substrata at day 14, as proved by SEM and x-ray diffraction (XRD), strongly indicated the bioactivity of coated substrata. In addition, MC3T3-E1 cells were cultured on the coated substrata to evaluate cellular activities. Compared with the non-coated substrata and tissue culture plates, no significant difference was observed on the coated substrata in terms of cytotoxicity, viability, proliferation and apoptosis. However, interestingly, higher levels of alkaline phosphatase (ALP) activity and osteocalcin (OC) secretion were observed on the coated substrata, indicating that GO coatings enhanced cell differentiation compared with non-coated substrata and tissue culture plates. This study suggests that GO coatings had excellent biocompatibility and more importantly promoted MC3T3-E1 cell differentiation and might be a good candidate as a coating material for orthopedic implants.

  2. Genetic responses to nanostructured calcium-phosphate-coated implants.

    PubMed

    Jimbo, R; Xue, Y; Hayashi, M; Schwartz-Filho, H O; Andersson, M; Mustafa, K; Wennerberg, A

    2011-12-01

    Nanostructured calcium phosphate (CaP) has been histologically and biomechanically proven to enhance osseointegration of implants; however, conventional techniques were not sufficiently sensitive to capture its biological effects fully. Here, we compared the conventional removal torque (RTQ) evaluation and gene expression in tissues around nanostructured CaP-coated implants, using real-time RT-PCR, with those of uncoated implants, in a rabbit model. At 2 wks, RTQ values were significantly higher, alkaline phosphatase (ALP) expression was significantly higher, and runt-related transcription factor 2 and tumor necrosis factor-α expressions were significantly lower in the coated than in the uncoated implants. This indicates that inflammatory responses were suppressed and osteoprogenitor activity increased around the CaP-coated surface. At 4 wks, although RTQ values did not significantly differ between the 2 groups, ALP and osteocalcin (OCN) were significantly up-regulated in the coated group, indicating progressive mineralization of the bone around the implant. Moreover, an osteoclast marker, adenosine triphosphatase, which indicates acidification of the resorption lacunae, was significantly higher for the coated implants, suggesting gradual resorption of the CaP coating. This study reveals detailed genetic responses to nanostructured CaP-coated implants and provides evidence that the effect of nanotopography is significant during the osseointegration cascade.

  3. Biological evaluation of ultrananocrystalline and nanocrystalline diamond coatings.

    PubMed

    Skoog, Shelby A; Kumar, Girish; Zheng, Jiwen; Sumant, Anirudha V; Goering, Peter L; Narayan, Roger J

    2016-12-01

    Nanostructured biomaterials have been investigated for achieving desirable tissue-material interactions in medical implants. Ultrananocrystalline diamond (UNCD) and nanocrystalline diamond (NCD) coatings are the two most studied classes of synthetic diamond coatings; these materials are grown using chemical vapor deposition and are classified based on their nanostructure, grain size, and sp(3) content. UNCD and NCD are mechanically robust, chemically inert, biocompatible, and wear resistant, making them ideal implant coatings. UNCD and NCD have been recently investigated for ophthalmic, cardiovascular, dental, and orthopaedic device applications. The aim of this study was (a) to evaluate the in vitro biocompatibility of UNCD and NCD coatings and (b) to determine if variations in surface topography and sp(3) content affect cellular response. Diamond coatings with various nanoscale topographies (grain sizes 5-400 nm) were deposited on silicon substrates using microwave plasma chemical vapor deposition. Scanning electron microscopy and atomic force microscopy revealed uniform coatings with different scales of surface topography; Raman spectroscopy confirmed the presence of carbon bonding typical of diamond coatings. Cell viability, proliferation, and morphology responses of human bone marrow-derived mesenchymal stem cells (hBMSCs) to UNCD and NCD surfaces were evaluated. The hBMSCs on UNCD and NCD coatings exhibited similar cell viability, proliferation, and morphology as those on the control material, tissue culture polystyrene. No significant differences in cellular response were observed on UNCD and NCD coatings with different nanoscale topographies. Our data shows that both UNCD and NCD coatings demonstrate in vitro biocompatibility irrespective of surface topography.

  4. Fabrication of hydroxycarbonate apatite coatings with hierarchically porous structures.

    PubMed

    Guo, Yaping; Zhou, Yu; Jia, Dechang

    2008-03-01

    Hierarchically porous hydroxycarbonate apatite is known to have a high bioactivity to regenerate bone, but its application in bone graft substitutes has been restricted due to its poor mechanical properties. This drawback has been addressed by (i) depositing calcium carbonate coatings on Ti6Al4V substrates by electrophoresis; and (ii) converting the coatings to hydroxycarbonate apatite coatings with hierarchically porous structures by treatment with a phosphate buffer solution (PBS). After soaking calcium carbonate coatings in PBS for 1 day, calcium-deficient hydroxycarbonate apatite nanocrystals are deposited on the surfaces of calcium carbonate particles via a dissolution-precipitation reaction. The aggregation of the nanocrystals produces plate-like hydroxycarbonate apatite. Mesopores with a pore size of approximately 3.8nm and macropores or apertures with an aperture size of approximately 1 microm are formed within and among the plates, respectively. After soaking for 9 days, the pore size of mesopores decreases and the mesopores disappear partly due to the crystal growth of hydroxycarbonate apatite. Simulated body fluid immersion tests reveal that the good in vitro bioactivity of hydroxycarbonate apatite coatings is attributed to the calcium deficiencies in apatite lattice and the hierarchically porous structures.

  5. Biological Regulation of Bone Quality

    PubMed Central

    Alliston, Tamara

    2014-01-01

    The ability of bone to resist fracture is determined by the combination of bone mass and bone quality. Like bone mass, bone quality is carefully regulated. Of the many aspects of bone quality, this review focuses on biological mechanisms that control the material quality of the bone extracellular matrix (ECM). Bone ECM quality depends upon ECM composition and organization. Proteins and signaling pathways that affect the mineral or organic constituents of bone ECM impact bone ECM material properties, such as elastic modulus and hardness. These properties are also sensitive to pathways that regulate bone remodeling by osteoblasts, osteoclasts, and osteocytes. Several extracellular proteins, signaling pathways, intracellular effectors, and transcription regulatory networks have been implicated in the control of bone ECM quality. A molecular understanding of these mechanisms will elucidate the biological control of bone quality and suggest new targets for the development of therapies to prevent bone fragility. PMID:24894149

  6. Duplex aluminized coatings

    NASA Technical Reports Server (NTRS)

    Gedwill, M. A.; Grisaffe, S. J. (Inventor)

    1975-01-01

    The surface of a metallic base system is initially coated with a metallic alloy layer that is ductile and oxidation resistant. An aluminide coating is then applied to the metallic alloy layer. The chemistry of the metallic alloy layer is such that the oxidation resistance of the subsequently aluminized outermost layer is not seriously degraded.

  7. Coated ceramic breeder materials

    DOEpatents

    Tam, Shiu-Wing; Johnson, Carl E.

    1987-04-07

    A breeder material for use in a breeder blanket of a nuclear reactor is disclosed. The breeder material comprises a core material of lithium containing ceramic particles which has been coated with a neutron multiplier such as Be or BeO, which coating has a higher thermal conductivity than the core material.

  8. Thermal barrier coating

    DOEpatents

    Bowker, Jeffrey Charles; Sabol, Stephen M.; Goedjen, John G.

    2001-01-01

    A thermal barrier coating for hot gas path components of a combustion turbine based on a zirconia-scandia system. A layer of zirconium scandate having the hexagonal Zr.sub.3 Sc.sub.4 O.sub.12 structure is formed directly on a superalloy substrate or on a bond coat formed on the substrate.

  9. Molecular Adsorber Coating

    NASA Technical Reports Server (NTRS)

    Straka, Sharon; Peters, Wanda; Hasegawa, Mark; Hedgeland, Randy; Petro, John; Novo-Gradac, Kevin; Wong, Alfred; Triolo, Jack; Miller, Cory

    2011-01-01

    A document discusses a zeolite-based sprayable molecular adsorber coating that has been developed to alleviate the size and weight issues of current ceramic puck-based technology, while providing a configuration that more projects can use to protect against degradation from outgassed materials within a spacecraft, particularly contamination-sensitive instruments. This coating system demonstrates five times the adsorption capacity of previously developed adsorber coating slurries. The molecular adsorber formulation was developed and refined, and a procedure for spray application was developed. Samples were spray-coated and tested for capacity, thermal optical/radiative properties, coating adhesion, and thermal cycling. Work performed during this study indicates that the molecular adsorber formulation can be applied to aluminum, stainless steel, or other metal substrates that can accept silicate-based coatings. The coating can also function as a thermal- control coating. This adsorber will dramatically reduce the mass and volume restrictions, and is less expensive than the currently used molecular adsorber puck design.

  10. Coated electroactive materials

    DOEpatents

    Amine, Khalil; Abouimrane, Ali

    2016-08-30

    A process includes suspending an electroactive material in a solvent, suspending or dissolving a carbon precursor in the solvent; and depositing the carbon precursor on the electroactive material to form a carbon-coated electroactive material. Compositions include a graphene-coated electroactive material prepared from a solution phase mixture or suspension of an electroactive material and graphene, graphene oxide, or a mixture thereof.

  11. Thermal barrier coating system

    NASA Technical Reports Server (NTRS)

    Stecura, S. (Inventor)

    1985-01-01

    An oxide thermal barrier coating comprises ZrO3-Yb2O3 that is plasma sprayed onto a previously applied bond coating. The zirconia is partially stabilized with about 124 w/o ytterbia to insure cubic, monoclinic, and terragonal phases.

  12. Anti-Corrosion Coating

    NASA Technical Reports Server (NTRS)

    1977-01-01

    NASA-Goddard developed a zinc-rich coating with a special binder that exhibits longer life and booths with the air purifiers. superior adhesion characteristics-so that only a single coat is required. Unlike conventional coatings, . the NASA compound is easy to mix and it requires no straining before application; its materials also cost less. Thus the new coating offers cost advantages in materials, labor hours per application, and fewer applications over a given time span. The NASA coating is now undergoing test on a number of coastal area structures. In a cooperative effort with the Philadelphia Mayor's Science and Technology Council, the coating has been applied to sample sections of the Frankford Elevated System's steel support structure. On the West Coast, it is being tested on facilities of the Pillar Point Satellite Tracking Station, Pillar Point, Cat. and on segments of the Golden Gate Bridge. It is also undergoing evaluation as an undercoating to protect road equipment against de-icing salts; the coating was applied to the underside of a truck and its performance is being recorded periodically by the Vermont Department of Highways. NASA has issued patent licenses to two paint companies and the coating is expected to be commercially available this year.

  13. Coated ceramic breeder materials

    DOEpatents

    Tam, Shiu-Wing; Johnson, Carl E.

    1987-01-01

    A breeder material for use in a breeder blanket of a nuclear reactor is disclosed. The breeder material comprises a core material of lithium containing ceramic particles which has been coated with a neutron multiplier such as Be or BeO, which coating has a higher thermal conductivity than the core material.

  14. Bioactive cell-derived matrices combined with polymer mesh scaffold for osteogenesis and bone healing.

    PubMed

    Kim, In Gul; Hwang, Mintai P; Du, Ping; Ko, Jaehoon; Ha, Chul-won; Do, Sun Hee; Park, Kwideok

    2015-05-01

    Successful bone tissue engineering generally requires an osteoconductive scaffold that consists of extracellular matrix (ECM) to mimic the natural environment. In this study, we developed a PLGA/PLA-based mesh scaffold coated with cell-derived extracellular matrix (CDM) for the delivery of bone morphogenic protein (BMP-2), and assessed the capacity of this system to provide an osteogenic microenvironment. Decellularized ECM from human lung fibroblasts (hFDM) was coated onto the surface of the polymer mesh scaffolds, upon which heparin was then conjugated onto hFDM via EDC chemistry. BMP-2 was subsequently immobilized onto the mesh scaffolds via heparin, and released at a controlled rate. Human placenta-derived mesenchymal stem cells (hPMSCs) were cultured in such scaffolds and subjected to osteogenic differentiation for 28 days in vitro. The results showed that alkaline phosphatase (ALP) activity, mineralization, and osteogenic marker expression were significantly improved with hPMSCs cultured in the hFDM-coated mesh scaffolds compared to the control and fibronectin-coated ones. In addition, a mouse ectopic and rat calvarial bone defect model was used to examine the feasibility of current platform to induce osteogenesis as well as bone regeneration. All hFDM-coated mesh groups exhibited a significant increase of newly formed bone and in particular, hFDM-coated mesh scaffold loaded with a high dose of BMP-2 exhibited a nearly complete bone defect healing as confirmed via micro-CT and histological observation. This work proposes a great potency of using hFDM (biophysical) coupled with BMP-2 (biochemical) as a promising osteogenic microenvironment for bone tissue engineering applications.

  15. Fine grained osseointegrative coating improves biocompatibility of PEEK in heterotopic sheep model

    PubMed Central

    Verleye, Gino B.M.; Smeets, Dirk; Van Hauwermeiren, Hadewych Y.R.; Loeckx, Dirk; Willems, Karel; Siau, Vincent G.M.G.G.B.; Lauweryns, Philippe J.M.E.

    2015-01-01

    Background and aim Polyetheretherketone (PEEK) materials already have been used successfully in orthopedic and especially spine surgery. PEEK is radiolucent and comparable with bone regarding elasticity. However, PEEK is inert and the adhesion of PEEK implants to bone tissue proceeds slowly because of their relatively low biocompatibility. The aim of the study is to evaluate the effect of titanium and CaP coating on the adhesion of bone tissue. Material and Methods Six adult sheep (body weight 57.6 ± 3.9 kg) were included in this study. Three different types of cylindrical dowels (12 mm length x 8 mm diameter) were implanted in long bones (tibia and femur): PEEK dowels without coating (the control group), and PEEK dowels with a nanocoating of calcium phosphate (CaP group) or titanium (titanium group). Animals were sacrificed after 6, 12 and 26 weeks. Dowels were explanted for micro CT and histology. Results Bone implant contact (BIC) ratio was significantly higher in the titanium versus control groups in the 6 to 12 weeks period (p = 0.03). The ratio between bone volume and tissue volume (BV/TV) was significantly higher in titanium versus control in the 6 to 12 weeks period (p = 0.02). A significant correlation between BIC and BV/TV was seen (r = 0.85, p < 0.05). Conclusion Coating of PEEK dowels with a nanocoating of titanium has beneficial effects on adhesion of bone tissue. PMID:26273553

  16. Bio-Inspired Nano-Featured Substrates: Suitable Environment for Bone Regeneration.

    PubMed

    Rammal, Hassan; Dubus, Marie; Aubert, Léa; Reffuveille, Fany; Laurent Maquin, Dominique; Terryn, Christine; Schaaf, Pierre; Alem, Halima; Francius, Grégory; Quilès, Fabienne; Gangloff, Sophie C; Boulmedais, Fouzia; Kerdjoudj, Halima

    2017-03-16

    Bone mimicking coatings provide a complex microenvironment in which material, through its inherent properties (such as nanostructure and composition), affects the commitment of stem cells into bone lineage and the production of bone tissue regulating factors, required for bone healing and regeneration. Herein, a bioactive mineral/biopolymers composite made of calcium phosphate/chitosan and hyaluronic acid (CaP-CHI-HA) was elaborated using a versatile simultaneous spray coating of interacting species. The resulting CaP-CHI-HA coating was mainly constituted of bioactive, carbonated and crystalline hydroxyapatite, with 277 ± 98 nm of roughness, 1 μm of thickness and 2.3 ± 1 GPa of stiffness. After five days of culture, CaP-CHI-HA suggested a synergistic effect of intrinsic biophysical features and biopolymers on stem cells mechanobiology and nuclear organization, leading to the expression of an early osteoblast-like phenotype and the production of bone tissue regulating factors such as osteoprotegerin and vascular endothelial growth factor. More interestingly, amalgamation with biopolymers, conferred to mineral a bacterial anti-adhesive property. These significant data shed light on the potential regenerative application of CaP-CHI-HA bio-inspired coating in providing a suitable environment for stem cells bone regeneration and an ideal strategy to prevent implant-associated infections.

  17. Thermal barrier coatings

    SciTech Connect

    Alvin, Mary Anne

    2010-06-22

    This disclosure addresses the issue of providing a metallic-ceramic overlay coating that potentially serves as an interface or bond coat layer to provide enhanced oxidation resistance to the underlying superalloy substrate via the formation of a diffusion barrier regime within the supporting base material. Furthermore, the metallic-ceramic coating is expected to limit the growth of a continuous thermally grown oxide (TGO) layer that has been primarily considered to be the principal cause for failure of existing TBC systems. Compositional compatibility of the metallic-ceramic with traditional yttria-stabilized zirconia (YSZ) top coats is provided to further limit debond or spallation of the coating during operational use. A metallic-ceramic architecture is disclosed wherein enhanced oxidation resistance is imparted to the surface of nickel-based superalloy or single crystal metal substrate, with simultaneous integration of the yttria stabilized zirconia (YSZ) within the metallic-ceramic overlayer.

  18. LEVELING METAL COATINGS

    DOEpatents

    Gage, H.A.

    1959-02-10

    A method is described for applying metallic coatings to a cylinder of uranium. An aluminum-silicon coat is applied by a process consisting of first cleaning the article by immersion for 5 minutes in 50% nitric acid at 65 C. The article then is dipped through a flux, prepared by adding 10% sodium fluoride to 90% of a flux comprising 53% potassium chloride, 42% lithium chloride, and 5% sodium chloride at 560 for 2 minutes and then directly into a molten metal bath comprising 99% aluminun and 12% silicon at 620 C for 3 minutes. While the coating is yet molten the article is transferred to a pair of steel rollers and rolled until the coating solidifies. By varying the composition of the flux other metals such as zinc, lead or the like may be coated on uranium in a similar manner.

  19. Catalytic thermal barrier coatings

    DOEpatents

    Kulkarni, Anand A.; Campbell, Christian X.; Subramanian, Ramesh

    2009-06-02

    A catalyst element (30) for high temperature applications such as a gas turbine engine. The catalyst element includes a metal substrate such as a tube (32) having a layer of ceramic thermal barrier coating material (34) disposed on the substrate for thermally insulating the metal substrate from a high temperature fuel/air mixture. The ceramic thermal barrier coating material is formed of a crystal structure populated with base elements but with selected sites of the crystal structure being populated by substitute ions selected to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a higher rate than would the base compound without the ionic substitutions. Precious metal crystallites may be disposed within the crystal structure to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a lower light-off temperature than would the ceramic thermal barrier coating material without the precious metal crystallites.

  20. [Bone and Nutrition. Sclerostin and bone metabolism].

    PubMed

    Tatsumi, Sawako; Nagamoto, Kenta; Ogata, Mao; Miyamoto, Ken-ichi

    2015-07-01

    Osteocytes orchestrate bone resorption and bone formation by controlling osteoclast and osteoblast activity. On the other hand, osteocytes secret FGF23 (fibroblast growth factor 23), FGF23 acts on the kidney to control phosphate homeostasis. Sclerostin is also released from osteocytes and it regulated osteoblast activity through Wnt/β-catenin pathway. Therefore, an antibody that targets sclerostin is currently in phase- III clinical trials for the treatment of osteoporosis and it is expected as new therapeutics.

  1. [Fibrous dysplasia of bone].

    PubMed

    Orcel, Philippe; Chapurlat, Roland

    2007-10-31

    Fibrous dysplasia of bone is a congenital non hereditary benign bone disease, where normal bone is replaced by a fibrous-like tissue with immature osteogenesis. Prevalence is difficult to estimate, due to frequent asymptomatic lesions. Bone lesions are mono- or polyostotic and may be associated with bone pain and fragility, leading to fractures. In some patients or bone sites, they are hypertrophic, responsible for neurological complications. Imaging and, when necessary, histology are the cornerstones of the diagnosis. A common molecular defect, i.e. activating mutations of the GNAS gene, encoding the a subunit of the Gs protein in target cells, is responsible for bone cell alterations as well as for the involvement of other cells/tissues bearing the same molecular defect (melanocytes, endocrine cells). These mutations affect only somatic cells and are therefore not hereditary: antenatal diagnosis is not appropriate for this disease and genetic counselling is not very useful, except for reassuring the patients. The conventional therapeutic approach is essentially symptomatic (pain killers) and orthopaedic (prevention and treatment of bone complications). Recent publications have focused attention on pamidronate, which rapidly relieves bone pain in most patients, and progressively increases bone mineralization in osteolytic areas in about half of the patients. Tubular phosphate wasting is common and should be treated with phosphate supplement and calcitriol. The prognosis should improve with therapeutic advances, but this remains to be properly evaluated.

  2. Coating Reduces Ice Adhesion

    NASA Technical Reports Server (NTRS)

    Smith, Trent; Prince, Michael; DwWeese, Charles; Curtis, Leslie

    2008-01-01

    The Shuttle Ice Liberation Coating (SILC) has been developed to reduce the adhesion of ice to surfaces on the space shuttle. SILC, when coated on a surface (foam, metal, epoxy primer, polymer surfaces), will reduce the adhesion of ice by as much as 90 percent as compared to the corresponding uncoated surface. This innovation is a durable coating that can withstand several cycles of ice growth and removal without loss of anti-adhesion properties. SILC is made of a binder composed of varying weight percents of siloxane(s), ethyl alcohol, ethyl sulfate, isopropyl alcohol, and of fine-particle polytetrafluoroethylene (PTFE). The combination of these components produces a coating with significantly improved weathering characteristics over the siloxane system alone. In some cases, the coating will delay ice formation and can reduce the amount of ice formed. SILC is not an ice prevention coating, but the very high water contact angle (greater than 140 ) causes water to readily run off the surface. This coating was designed for use at temperatures near -170 F (-112 C). Ice adhesion tests performed at temperatures from -170 to 20 F (-112 to -7 C) show that SILC is a very effective ice release coating. SILC can be left as applied (opaque) or buffed off until the surface appears clear. Energy dispersive spectroscopy (EDS) and x-ray photoelectron spectroscopy (XPS) data show that the coating is still present after buffing to transparency. This means SILC can be used to prevent ice adhesion even when coating windows or other objects, or items that require transmission of optical light. Car windshields are kept cleaner and SILC effectively mitigates rain and snow under driving conditions.

  3. Hybrid use of combined and sequential delivery of growth factors and ultrasound stimulation in porous multilayer composite scaffolds to promote both vascularization and bone formation in bone tissue engineering.

    PubMed

    Yan, Haoran; Liu, Xia; Zhu, Minghua; Luo, Guilin; Sun, Tao; Peng, Qiang; Zeng, Yi; Chen, Taijun; Wang, Yingying; Liu, Keliang; Feng, Bo; Weng, Jie; Wang, Jianxin

    2016-01-01

    In this study, a multilayer coating technology would be adopted to prepare a porous composite scaffold and the growth factor release and ultrasound techniques were introduced into bone tissue engineering to finally solve the problems of vascularization and bone formation in the scaffold whilst the designed multilayer composite with gradient degradation characteristics in the space was used to match the new bone growth process better. The results of animal experiments showed that the use of low intensity pulsed ultrasound (LIPUS) combined with growth factors demonstrated excellent capabilities and advantages in both vascularization and new bone formation in bone tissue engineering. The degradation of the used scaffold materials could match new bone formation very well. The results also showed that only RGD-promoted cell adhesion was insufficient to satisfy the needs of new bone formation while growth factors and LIPUS stimulation were the key factors in new bone formation.

  4. Multilayered DNA coatings: in vitro bioactivity studies and effects on osteoblast-like cell behavior.

    PubMed

    van den Beucken, J J J P; Walboomers, X F; Leeuwenburgh, S C G; Vos, M R J; Sommerdijk, N A J M; Nolte, R J M; Jansen, J A

    2007-07-01

    This study describes the effect of multilayered DNA coatings on (i) the formation of mineralized depositions from simulated body fluids (SBF); and (ii) osteoblast-like cell behavior with and without pretreatment in SBF. DNA coatings were generated using electrostatic self-assembly, with poly-d-lysine or poly(allylamine hydrochloride) as cationic polyelectrolytes, on titanium substrates. Coated substrates and non-coated controls were immersed in SBF with various compositions. The deposition of calcium phosphate was enhanced on multilayered DNA coatings as compared with non-coated controls, and was dependent on the type of cationic polyelectrolyte used in the build-up of the DNA coatings. Further analysis showed that the depositions consisted of carbonated apatite. Non-pretreated DNA coatings were found to have no effect on osteoblast-like cell behavior compared with titanium controls. On the other hand, SBF-pretreatment of DNA coatings affected the differentiation of osteoblast-like cells through an increased deposition of osteocalcin. The results of this study are indicative of the bone-bonding capacities of DNA coatings. Nevertheless, future animal experiments are required to provide conclusive evidence for the bioactivity of DNA coatings.

  5. Characterization, mechanical properties and corrosion resistance of biocompatible Zn-HA/TiO2 nanocomposite coatings.

    PubMed

    Mirak, Mohammad; Alizadeh, Morteza; Ghaffari, Mohammad; Ashtiani, Mohammad Najafi

    2016-09-01

    Biocompatible Zinc-hydroxyapatite-titania and Zinc-hydroxyapatite nanocomposite coatings have been prepared by electrodeposition on NiTi shape memory alloy. Structures of coatings were characterized using X-ray diffraction (XRD). It was found that addition of TiO2 particles cause to reduction of crystallite size of coating. Scanning Electronic Microscope (SEM) observation showed that the Zn-HA/TiO2 coating consists of plate-like regions which can express that this plate-like structure can facilitate bone growth. X-ray photoelectron microscope (XPS) was performed to investigation of chemical state of composite coating and showed that Zinc matrix was bonded to oxygen. high-resolution transmission electron microscope (HRTEM) result illustrated the crystalline structure of nanocomposite coating. Mechanical behavior of coating was evaluated using microhardness and ball on disk wear test. The TiO2 incorporated composite coatings exhibited the better hardness and anti-wear performance than the Zn-HA coatings. Polarization measurements have been used to evaluate the electrochemical coatings performance. The Zn-HA/TiO2 composite coatings showed the highest corrosion resistance compared with Zn-HA and bare NiTi.

  6. Nanoscale hydroxyapatite particles for bone tissue engineering.

    PubMed

    Zhou, Hongjian; Lee, Jaebeom

    2011-07-01

    Hydroxyapatite (HAp) exhibits excellent biocompatibility with soft tissues such as skin, muscle and gums, making it an ideal candidate for orthopedic and dental implants or components of implants. Synthetic HAp has been widely used in repair of hard tissues, and common uses include bone repair, bone augmentation, as well as coating of implants or acting as fillers in bone or teeth. However, the low mechanical strength of normal HAp ceramics generally restricts its use to low load-bearing applications. Recent advancements in nanoscience and nanotechnology have reignited investigation of nanoscale HAp formation in order to clearly define the small-scale properties of HAp. It has been suggested that nano-HAp may be an ideal biomaterial due to its good biocompatibility and bone integration ability. HAp biomedical material development has benefited significantly from advancements in nanotechnology. This feature article looks afresh at nano-HAp particles, highlighting the importance of size, crystal morphology control, and composites with other inorganic particles for biomedical material development.

  7. Assessment of Long Bone Flexural Properties from Bone Densitometry

    NASA Technical Reports Server (NTRS)

    Whalen, Robert; Cleek, Tammy; Katz, BethAnn

    1994-01-01

    While bone densitometry is the accepted non-invasive method of quantifying bone mineral content in bones, its assessment of bone structural properties is less well understood. The objective of our current work is to compare cross-section shape or areal properties of long bones computed from densitometry data with cross-section flexural properties obtained from surface strain measurements.

  8. Genetic regulation of bone mass: from bone density to bone strength.

    PubMed

    Langman, Craig B

    2005-03-01

    Osteoporosis is a common disease characterized in adults by diminished bone density. Bone is an organ that evolves and grows throughout life, and establishing optimal bone density in childhood and adolescence serves to buffer bone loss later in life. Bone density, a measurable entity, is the clinical substitute for bone strength, or the ability to defend against fracture. Chronic diseases may adversely affect optimal peak bone density. Bone density is under genetic control, as revealed by three lines of investigations. These include (1) the finding of quantitative trait loci for bone density, (2) the finding that specific mutations in genes that are important in the development of osteoblast or osteoclast lineages alter bone density, and (3) the linkeage of known polymorphisms for genes involved in mineral homeostasis to bone density and/or fracture. Future therapeutics for improving peak bone density or delaying bone loss later in life may take advantage of the genetic nature of bone density development.

  9. Silver nanoparticles and growth factors incorporated hydroxyapatite coatings on metallic implant surfaces for enhancement of osteoinductivity and antibacterial properties.

    PubMed

    Xie, Chao-Ming; Lu, Xiong; Wang, Ke-Feng; Meng, Fan-Zhi; Jiang, Ou; Zhang, Hong-Ping; Zhi, Wei; Fang, Li-Ming

    2014-06-11

    Research on incorporation of both growth factors and silver (Ag) into hydroxyapatite (HA) coatings on metallic implant surfaces for enhancing osteoinductivity and antibacterial properties is a challenging work. Generally, Ag nanoparticles are easy to agglomerate and lead to a large increase in local Ag concentration, which could potentially affect cell activity. On the other hand, growth factors immobilization requires mild processing conditions so as to maintain their activities. In this study, bone morphology protein-2 (BMP-2) and Ag nanoparticle contained HA coatings were prepared on Ti surfaces by combining electrochemical deposition (ED) of Ag and electrostatic immobilization of BMP-2. During the ED process, chitosan (CS) was selected as the stabilizing agent to chelate Ag ions and generate Ag nanoparticles that are uniformly distributed in the coatings. CS also reduces Ag toxicity while retaining its antibacterial activity. Afterwards, a BMP/heparin solution was absorbed on the CS/Ag/HA coatings. Consequently, BMP-2 was immobilized on the coatings by the electrostatic attraction between CS, heparin, and BMP-2. Sustained release of BMP-2 and Ag ions from HA coatings was successfully demonstrated for a long period. Results of antibacterial tests indicate that the CS/Ag/HA coatings have high antibacterial properties against both Staphylococcus epidermidis and Escherichia coli. Osteoblasts (OB) culture reveals that the CS/Ag/HA coatings exhibit good biocompatibility. Bone marrow stromal cells (BMSCs) culture indicates that the BMP/CS/Ag/HA coatings have good osteoinductivity and promote the differentiation of BMSCs. Ti bars with BMP/CS/Ag/HA coatings were implanted into the femur of rabbits to evaluate the osteoinductivity of the coatings. Results indicate that BMP/CS/Ag/HA coatings favor bone formation in vivo. In summary, this study presents a convenient and effective method for the incorporation of growth factors and antibacterial agents into HA coatings. This

  10. Characterization of osseointegrative phosphatidylserine and cholesterol orthopaedic implant coatings

    NASA Astrophysics Data System (ADS)

    Rodgers, William Paul, III

    Total joint arthroplasties are one of the most successful surgeries available today for improving patients' quality of life. Increasing demand is driven largely by an ageing population and an increased occurrence of obesity. Current patient options have significant shortcomings. Nearly a third of patients require a revision surgery before the implant is 15 years old, and those who have revision surgeries are at an increased risk of requiring additional reoperations. A recent implant technology that has shown to be effective at improving bone to implant integration is the use of phosphatidylserine (DOPS) coatings. These coatings are challenging to analyze and measure due to their highly dynamic, soft, rough, thick, and optically diffractive properties. Previous work had difficulty investigating pertinent parameters for these coating's development due in large part to a lack of available analytical techniques and a dearth of understanding of the micro- and nano-structural configuration of the coatings. This work addresses the lack of techniques available for use with DOPS coatings through the development of original methods of measurement, including the use of scanning white light interferometry and nanoindentation. These techniques were then applied for the characterization of DOPS coatings and the study of effects from several factors: 1. influence of adding calcium and cholesterol to the coatings, 2. effects of composition and roughness on aqueous contact angles, and 3. impact of ageing and storage environment on the coatings. Using these newly developed, highly repeatable quantitative analysis methods, this study sheds light on the microstructural configuration of the DOPS coatings and elucidates previously unexplained phenomena of the coatings. Cholesterol was found to supersaturate in the coatings at high concentration and phase separate into an anhydrous crystalline form, while lower concentrations were found to significantly harden the coatings. Morphological

  11. Biomaterials and bone mechanotransduction

    NASA Technical Reports Server (NTRS)

    Sikavitsas, V. I.; Temenoff, J. S.; Mikos, A. G.; McIntire, L. V. (Principal Investigator)

    2001-01-01

    Bone is an extremely complex tissue that provides many essential functions in the body. Bone tissue engineering holds great promise in providing strategies that will result in complete regeneration of bone and restoration of its function. Currently, such strategies include the transplantation of highly porous scaffolds seeded with cells. Prior to transplantation the seeded cells are cultured in vitro in order for the cells to proliferate, differentiate and generate extracellular matrix. Factors that can affect cellular function include the cell-biomaterial interaction, as well as the biochemical and the mechanical environment. To optimize culture conditions, good understanding of these parameters is necessary. The new developments in bone biology, bone cell mechanotransduction, and cell-surface interactions are reviewed here to demonstrate that bone mechanotransduction is strongly influenced by the biomaterial properties.

  12. Bone Surface Mapping Method

    PubMed Central

    Fan, Yifang; Fan, Yubo; Li, Zhiyu; Lv, Changsheng; Zhang, Bo

    2012-01-01

    Bone shape is an important factor to determine the bone's structural function. For the asymmetrically shaped and anisotropically distributed bone in vivo, a surface mapping method is proposed on the bases of its geometric transformation invariance and its uniqueness of the principal axes of inertia. Using spiral CT scanning, we can make precise measurements to bone in vivo. The coordinate transformations lead to the principal axes of inertia, with which the prime meridian and the contour can be set. Methods such as tomographic reconstruction and boundary development are employed so that the surface of bone in vivo can be mapped. Experimental results show that the surface mapping method can reflect the shape features and help study the surface changes of bone in vivo. This method can be applied to research into the surface characteristics and changes of organ, tissue or cell whenever its digitalized surface is obtained. PMID:22412952

  13. Biophotonics and Bone Biology

    NASA Technical Reports Server (NTRS)

    Zimmerli, Gregory; Fischer, David; Asipauskas, Marius; Chauhan, Chirag; Compitello, Nicole; Burke, Jamie; Tate, Melissa Knothe

    2004-01-01

    One of the more-serious side effects of extended space flight is an accelerated bone loss [Bioastronautics Critical Path Roadmap, http://research.hq.nasa.gov/code_u/bcpr/index.cfm]. Rates of bone loss are highest in the weight-bearing bones of the hip and spine regions, and the average rate of bone loss as measured by bone mineral density measurements is around 1.2% per month for persons in a microgravity environment. It shows that an extrapolation of the microgravity induced bone loss rates to longer time scales, such as a 2.5 year round-trip to Mars (6 months out at 0 g, 1.5 year stay on Mars at 0.38 g, 6 months back at 0 g), could severely compromise the skeletal system of such a person.

  14. Biomaterials and bone mechanotransduction.

    PubMed

    Sikavitsas, V I; Temenoff, J S; Mikos, A G

    2001-10-01

    Bone is an extremely complex tissue that provides many essential functions in the body. Bone tissue engineering holds great promise in providing strategies that will result in complete regeneration of bone and restoration of its function. Currently, such strategies include the transplantation of highly porous scaffolds seeded with cells. Prior to transplantation the seeded cells are cultured in vitro in order for the cells to proliferate, differentiate and generate extracellular matrix. Factors that can affect cellular function include the cell-biomaterial interaction, as well as the biochemical and the mechanical environment. To optimize culture conditions, good understanding of these parameters is necessary. The new developments in bone biology, bone cell mechanotransduction, and cell-surface interactions are reviewed here to demonstrate that bone mechanotransduction is strongly influenced by the biomaterial properties.

  15. Induction of osteoconductivity by BMP-2 gene modification of mesenchymal stem cells combined with plasma-sprayed hydroxyapatite coating

    NASA Astrophysics Data System (ADS)

    Wu, Jiang; Guo, Ying-qiang; Yin, Guang-fu; Chen, Huai-qing; Kang, Yunqing

    2008-11-01

    Success in bone implant depends greatly on the composition and surface features of the implant. The surface-modification measures not only favor the implant's osteoconductivity, but also promote both bone anchoring and biomechanical stability. This paper reports an approach to combine a hydroxyapatite (HA) coated substrate with a cellular vehicle for the delivery of bone morphogenetic protein-2 (BMP-2) synergistically enhancing the osteoconductivity of implant surfaces. We examined the attachment, growth and osteoinductive activity of transfected BMP-producing bone marrow mesenchymal stem cells (BMSCs) on a plasma-sprayed HA coated substrate. It was found that the HA coated substrate could allow the attachment and growth of BMP-2 gene modified BMSCs, and this combined application synergistically enhanced osteconductivity of the substrate surface. This synergistic method may be of osseointegration value in orthopedic and dental implant surgery.

  16. Phenol-formaldehyde intumescent coating composition and coating prepared therefrom

    NASA Technical Reports Server (NTRS)

    Salyer, Ival O. (Inventor); Fox, Bernard L. (Inventor)

    1986-01-01

    Intumescent coatings which form a thick, uniform, fine celled, low density foam upon exposure to a high intensity heat flux or flame are disclosed, the invention coatings comprise phenolic resin prepolymer containing a blowing agent and a nucleating agent; in the preferred embodiments the coatings also contains a silicone surfactant, the coatings are useful in thermal and fire protection systems.

  17. Isomolybdate conversion coatings

    NASA Technical Reports Server (NTRS)

    Minevski, Zoran (Inventor); Maxey, Jason (Inventor); Nelson, Carl (Inventor); Eylem, Cahit (Inventor)

    2002-01-01

    A conversion coating solution and process forms a stable and corrosion-resistant layer on metal substrates or layers or, more preferably, on a boehmite layer or other base conversion coating. The conversion coating process involves contacting the substrate, layer or coating with an aqueous alkali metal isomolybdate solution in order to convert the surface of the substrate, layer or coating to a stable conversion coating. The aqueous alkali metal molybdates are selected from sodium molybdate (Na.sub.2 MoO.sub.4), lithium molybdate (Li.sub.2 MoO.sub.4), potassium molybdate (K.sub.2 MoO.sub.4), or combinations thereof, with the most preferred alkali metal molybdate being sodium molybdate. The concentration of alkali metal molybdates in the solution is preferably less than 5% by weight. In addition to the alkali metal molybdates, the conversion coating solution may include alkaline metal passivators selected from lithium nitrate (LiNO.sub.3), sodium nitrate (NaNO.sub.3), ammonia nitrate (NH.sub.4 NO.sub.3), and combinations thereof; lithium chloride, potassium hexafluorozirconate (K.sub.2 ZrF.sub.6) or potassium hexafluorotitanate (K.sub.2 TiF.sub.6).

  18. Adrenal gland and bone.

    PubMed

    Hardy, Rowan; Cooper, Mark S

    2010-11-01

    The adrenal gland synthesizes steroid hormones from the adrenal cortex and catecholamines from the adrenal medulla. Both cortisol and adrenal androgens can have powerful effects on bone. The overproduction of cortisol in Cushing's disease leads to a dramatic reduction in bone density and an increase risk of fracture. Overproduction of adrenal androgens in congenital adrenal hyperplasia (CAH) leads to marked changes in bone growth and development with early growth acceleration but ultimately a significant reduction in final adult height. The role of more physiological levels of glucocorticoids and androgens on bone metabolism is less clear. Cortisol levels measured in elderly individuals show a weak correlation with measures of bone density and change in bone density over time with a high cortisol level associated with lower bone density and more rapid bone loss. Cortisol levels and the dynamics of cortisol secretion change with age which could also explain some age related changes in bone physiology. It is also now clear that adrenal steroids can be metabolized within bone tissue itself. Local synthesis of cortisol within bone from its inactive precursor cortisone has been demonstrated and the amount of cortisol produced within osteoblasts appears to increase with age. With regard to adrenal androgens there is a dramatic reduction in levels with aging and several studies have examined the impact that restoration of these levels back to those seen in younger individuals has on bone health. Most of these studies show small positive effects in women, not men, but the skeletal sites where benefits are seen varies from study to study.

  19. Nanocomposites and bone regeneration

    NASA Astrophysics Data System (ADS)

    James, Roshan; Deng, Meng; Laurencin, Cato T.; Kumbar, Sangamesh G.

    2011-12-01

    This manuscript focuses on bone repair/regeneration using tissue engineering strategies, and highlights nanobiotechnology developments leading to novel nanocomposite systems. About 6.5 million fractures occur annually in USA, and about 550,000 of these individual cases required the application of a bone graft. Autogenous and allogenous bone have been most widely used for bone graft based therapies; however, there are significant problems such as donor shortage and risk of infection. Alternatives using synthetic and natural biomaterials have been developed, and some are commercially available for clinical applications requiring bone grafts. However, it remains a great challenge to design an ideal synthetic graft that very closely mimics the bone tissue structurally, and can modulate the desired function in osteoblast and progenitor cell populations. Nanobiomaterials, specifically nanocomposites composed of hydroxyapatite (HA) and/or collagen are extremely promising graft substitutes. The biocomposites can be fabricated to mimic the material composition of native bone tissue, and additionally, when using nano-HA (reduced grain size), one mimics the structural arrangement of native bone. A good understanding of bone biology and structure is critical to development of bone mimicking graft substitutes. HA and collagen exhibit excellent osteoconductive properties which can further modulate the regenerative/healing process following fracture injury. Combining with other polymeric biomaterials will reinforce the mechanical properties thus making the novel nano-HA based composites comparable to human bone. We report on recent studies using nanocomposites that have been fabricated as particles and nanofibers for regeneration of segmental bone defects. The research in nanocomposites, highlight a pivotal role in the future development of an ideal orthopaedic implant device, however further significant advancements are necessary to achieve clinical use.

  20. Bone scanning in otolaryngology.

    PubMed

    Noyek, A M

    1979-09-01

    Modern radionuclide bone scanning has introduced a new concept in physiologic and anatomic diagnostic imaging to general medicine. As otolaryngologists must diagnose and treat disease in relation to the bony and/or cartilaginous supporting structures of the neurocranium and upper airway, this modality should be included in the otolaryngologist's diagnostic armamentarium. It is the purpose of this manuscript to study the specific applications of bone scanning to our specialty at this time, based on clinical experience over the past three years. This thesis describes the development of bone scanning in general (history of nuclear medicine and nuclear physics; history of bone scanning in particular). General concepts in nuclear medicine are then presented; these include a discussion of nuclear semantics, principles of radioactive emmissions, the properties 99mTc as a radionuclide, and the tracer principle. On the basis of these general concepts, specific concepts in bone scanning are then brought forth. The physiology of bone and the action of the bone scan agents is presented. Further discussion considers the availability and production of the bone scan agent, patient factors, the gamma camera, the triphasic bone scan and the ultimate diagnostic principle of the bone scan. Clinical applications of bone scanning in otolaryngology are then presented in three sections. Proven areas of application include the evaluation of malignant tumors of the head and neck, the diagnosis of temporomandibular joint disorders, the diagnosis of facial fractures, the evaluation of osteomyelitis, nuclear medicine imaging of the larynx, and the assessment of systemic disease. Areas of adjunctive or supplementary value are also noted, such as diagnostic imaging of meningioma. Finally, areas of marginal value in the application of bone scanning are described.

  1. Radionuclide bone imaging and densitometry

    SciTech Connect

    Mettler, F.A.

    1988-01-01

    This book contains 13 selections. Some of the titles are: Radionuclides and the Normal Bone Scan; The Radionuclide Bone Scan in Malignant Disease; Pediatric Applications of Radionuclide Bone Imaging; The Radionuclide Bone Scan in Arthritis and Metabolic and Miscellaneous Disorders; and Soft Tissue Activity on the Radionuclide Bone Scan.

  2. Bone scanning in clinical practice

    SciTech Connect

    Fogelman, I. )

    1987-01-01

    The topics covered in this book include the history of bone scanning, mechanisms of uptake of diphosphonate in bone, the normal bone scan, and the role of bone scanning in clinical practice. The aim of this book is to provide a source of reference relating to bone scan imaging for all those who are interested in the skeleton.

  3. Reducing bone cancer cell functions using selenium nanocomposites.

    PubMed

    Stolzoff, Michelle; Webster, Thomas J

    2016-02-01

    Cancer recurrence at the site of tumor resection remains a major threat to patient survival despite modern cancer therapeutic advances. Osteosarcoma, in particular, is a very aggressive primary bone cancer that commonly recurs after surgical resection, radiation, and chemotherapeutic treatment. The objective of the present in vitro study was to develop a material that could decrease bone cancer cell recurrence while promoting healthy bone cell functions. Selenium is a natural part of our diet which has shown promise for reducing cancer cell functions, inhibiting bacteria, and promoting healthy cells functions, yet, it has not been widely explored for osteosarcoma applications. For this purpose, due to their increased surface area, selenium nanoparticles (SeNP) were precipitated on a very common orthopedic tissue engineering material, poly-l-lactic acid (or PLLA). Selenium-coated PLLA materials were shown to selectively decrease long-term osteosarcoma cell density while promoting healthy, noncancerous, osteoblast functions (for example, up to two times more alkaline phosphatase activity on selenium coated compared to osteoblasts grown on typical tissue culture plates), suggesting they should be further studied for replacing tumorous bone tissue with healthy bone tissue. Importantly, results of this study were achieved without the use of chemotherapeutics or pharmaceutical agents, which have negative side effects.

  4. Aging and Bone

    PubMed Central

    Boskey, A.L.; Coleman, R.

    2010-01-01

    Bones provide mechanical and protective function, while also serving as housing for marrow and a site for regulation of calcium ion homeostasis. The properties of bones do not remain constant with age; rather, they change throughout life, in some cases improving in function, but in others, function deteriorates. Here we review the modifications in the mechanical function and shape of bones, the bone cells, the matrix they produce, and the mineral that is deposited on this matrix, while presenting recent theories about the factors leading to these changes. PMID:20924069

  5. Biophotonics and Bone Biology

    NASA Technical Reports Server (NTRS)

    Zimmerli, Gregory; Fischer, David; Asipauskas, Marius; Chauhan, Chirag; Compitello, Nicole; Burke, Jamie; Tate, Melissa Knothe

    2004-01-01

    One of the more serious side effects of extended space flight is an accelerated bone loss. Rates of bone loss are highest in the weight-bearing bones of the hip and spine regions, and the average rate of bone loss as measured by bone mineral density measurements is around 1.2% per month for persons in a microgravity environment. I