In this study, a new trimethacrylate monomer ,,'-tri[4-(2'-hydroxy-3'-methacryloyloxy-propoxy)phenyl]-1-ethyl-4-isopropylbenzene (,,'-THMPEIB) with a molecular weight of 850 and a large molecular volume was designed and synthesized. The structure of monomer ,,'-THMPEIB was confirmed by FT-IR, ¹H NMR, and elemental analysis. Degree of double-bond conversion, volume shrinkage, water sorption and solubility, diffusion coefficient value, and flexure strength of ,,'-THMPEIB/tri(ethylene glycol) dimethacrylate- (TEGDMA) based resin were measured. 2,2-Bis[4-(2'-hydroxy-3'-methacryloyloxy-propoxy)-phenyl]-propane (bis-GMA)/TEGDMA monomer mixture was used as reference. The result showed that the ,,'-THMPEIB/TEGDMA-based resin had the lower double-bond conversion, polymerization shrinkage, and water solubility than bis-GMA/TEGDMA-based resin. Water sorption and diffusion coefficient value of ,,'-THMPEIB/TEGDMA-based resin were nearly the same as those of bis-GMA/TEGDMA-based resin. Flexural strength of ,,'-THMPEIB/TEGDMA-based resin was higher than that of bis-GMA/TEGDMA-based resin.

A modified titanium surface, anodized after being discharged in electrolytes, provides antibacterial activity against oral bacteria as well as osteoconductivity. However, the mechanism of this antibacterial effect against oral bacteria is still unclear. This study aims to investigate whether it is the chloride or the hydrophilicity properties of the anodized titanium, which is effective against the oral bacteria. Titanium plates are anodized in various electrolytes with or without chloride and are characterized. Then the survival of Streptococcus mutans on each specimen is evaluated. The results demonstrate that the peroxidation effects of HClO generated from the TiCl₃ formed on the titanium surface anodized in various chloride solutions efficiently killed adherent S. mutans on the surface whereas the presence of hydrophilicity alone do not demonstrate antibacterial activity. This method of anodizing titanium surface in a chloride solution may provide a novel strategy for use in orthopedic or dental implant systems.

Ultra high molecular weight polyethylene cups, 22 mm in diameter, were aged for 5 years in the normal laboratory environment. Half of the samples had been processed by the standard radiation sterilization techniques, while the remainder had been cross-linked by a technique involving higher radiation doses and controlled temperature at the time of irradiation. The samples had been tested in a hip simulator for 5,000,000 cycles using a lubricant that had been diluted 1 : 1 with deionized water. Once that testing was completed, further testing was conducted using lubricant with greater and lesser serum protein concentrations, and the results compared with those that had already been recorded. Comparison of the wear rates within the study as well as to published data concerning the effect of serum concentration showed results that were consistent with assumed differences in lubrication ability at different concentrations. The results of other published studies were found to be inconsistent with each other and different from some of the results of this study. There is shown to be a need for carefully controlled and conducted studies to agree, if possible, on the importance of the serum concentration and the appropriate parameters to be used in testing, as well as variations that may be necessary with different bearing material characteristics.

In this study we investigate the potential of femtosecond laser generated micrometer sized spike structures as functional surfaces for selective cell controlling. The spike dimensions as well as the average spike to spike distance can be easily tuned by varying the process parameters. Moreover, negative replications in soft materials such as silicone elastomer can be produced. This allows tailoring of wetting properties of the spike structures and their negative replicas representing a reduced surface contact area. Furthermore, we investigated material effects on cellular behavior. By comparing human fibroblasts and SH-SY5Y neuroblastoma cells we found that the influence of the material was cell specific. The cells not only changed their morphology, but also the cell growth was affected. Whereas, neuroblastoma cells proliferated at the same rate on the spike structures as on the control surfaces, the proliferation of fibroblasts was reduced by the spike structures. These effects can result from the cell specific adhesion patterns as shown in this work. These findings show a possibility to design defined surface microstructures, which could control cellular behavior in a cell specific manner.

The use of bone grafts is an essential component in spinal fusion. Autologous bone has been shown to result in long-term stable arthrodesis between spinal motion segments. However, autograft can be associated with significant morbidity and a limited supply. Alternatives, such as allogeneic demineralized bone matrix (DBM), are a potential source and supplement to autograft bone. The current study compares the ability of a DBM product (BioSet^® RT) and a coralline hydroxyapatite (Pro Osteon^® 500R), for inducing spinal fusion in a rabbit model. BioSet^® RT, alone or in combination with autograft, and Pro Osteon^® 500R were implanted in the posterior lateral inter-transverse process region of the rabbit spine. The spines were evaluated at 18 weeks for fusion of the L4–L5 transverse processes using a total of 33 skeletally mature male rabbits; 4 naïve animals were also included in the study. Samples were evaluated radiographically, histologically, by palpation, and through mechanical strength testing. Radiographical, histological, and palpation measurements demonstrated the ability of BioSet^® RT to induce new bone formation and bridging fusion comparable to autograft. This material performed well alone or in combination with autograft material. Despite significantly higher biomechanical testing results, minimal bone formation and fusion was recorded for the Pro Osteon^® 500R-treated group. This in vivo study demonstrates the ability of BioSet^® RT to induce new bone formation, and there was a clear relationship between bridging bone and mechanical strength.

Sulfobetaine-modified poly(ethylene terephthalate) (PET) systems were created by physically entrapping the zwitterionic species on the PET surface. The presence of the sulfobetiane molecules on these surfaces were verified by ATR-FTIR and SEM-EDAX analysis, while wettability of the films was investigated by water contact angle measurements. The blood compatibility of the modified films was evaluated by platelet adhesion in human platelet-rich plasma (PRP). The adhesion and inflammatory response of Mouse RAW 264.7 macrophage cells were studied. The surface induced cellular inflammatory response was determined by quantifying the expression levels of proinflammatory cytokines namely TNF- and IL-1β by measuring their mRNA profiles in the cells using real time polymerase chain reaction normalized to the housekeeping gene GAPDH. L-929 fibroblast cells were used to assess the propensity of the materials to support the fibroblast cell adhesion. A lower platelet adhesion and activation were observed on the sulfobetaine-modified PET film incubated in PRP after 2h when compared to control. The modified film reduced cellular adhesion events (p < 0.05) with respect to the base material, which could be linked to the reduced protein adsorption observed on this surface. The cellular inflammatory response was suppressed on sulfobetaine-modified substrate. Expression levels of pro-inflammmatory cytokines (TNF- and IL-1β) was found to be upregulated on bare PET, while it was significantly lower on modified PET (p < 0.001). Thus the sulfobetaine entrapment process can be applied on PET in order to achieve low biointeractions and reduced inflammatory host response for various biomedical and biotechnological applications.

Sustained intestinal delivery of thiamine hydrochloride (Vitamin B₁; VB₁) and pyridoxine hydrochloride (Vitamin B₆; VB₆) seems to be a feasible alternative to existing therapy. The vitamins (VB₁/VB₆) intercalated in montmorillonite (MMT) and intercalated VB₁/VB₆-MMT hybrid is further used for synthesis of VB₁/VB₆-MMT-alginate nanocomposite beads by gelation method and in vitro release in the intestinal environment. The structure and surface morphology of the synthesized VB₁/VB₆-MMT hybrid, VB₁/VB₆-alginate and VB₁/VB₆-MMT-alginate nanocomposite beads were characterized by XRD, FT-IR, TGA and SEM. In vitro release experiments revealed that the VB₁/VB₆ releases suddenly from VB₁/VB₆-MMT hybrid and is pH dependent. The controlled release of VB₁/VB₆ from VB₁/VB₆-MMT-alginate nanocomposite beads was observed to be controlled as compared to their release from VB₁/VB₆-MMT hybrid and VB₁/VB₆-alginate beads.

Surface modification of Ti-based metals is an important issue in improving the bone cell responses and bone-implant integration. Blasting Ti with granules (mostly alumina) is commonly used to prepare a clean surface and provide a level of roughness. In this study, glass granules with a bioactive composition were used as the blasting source to improve the surface bioactivity and biocompatibility of a Ti substrate. Bioactive glass particles with a composition of 70SiO₂ · 25CaO · 5P₂O₅ were prepared using a sol–gel method. A Ti disc was blasted with glass particles using a dental blasting unit (BG-Ti). A Ti disc blasted with commercial spherical-shaped glass (G-Ti) and a disc without blasting (Ti) were also prepared for comparison. The blasted Ti contained a large number of glass particles after the blasting process. The surface roughness of the samples in ascending order was G-Ti > BG-Ti > Ti. Murine-derived preosteoblasts (MC3T3-E1) were seeded on the samples, and the cell growth, differentiation, and mineralization behaviors were observed. The osteoblastic cells attached well and spread actively over all the sample groups with extensive cytoskeletal processes. The level of cell growth on the BG-Ti showed a continual increase with culturing up to 7 days, showing good cell viability. However, there was no significant difference (ANOVA, p < 0.05) with respect to the G-Ti and Ti groups. In particular, the alkaline phosphatase (AP) activity of the cells was significantly higher on the BG-Ti than on the other groups after culturing for 14 days. Moreover, the mineralization behavior of the cells, as assessed by Alizarin S Red, was superior on the BG-Ti to that observed on the other groups after culturing for 14 and 28 days. Overall, the blasting of Ti with a bioactive glass composition is considered beneficial for producing substrates with enhanced osteogenic potential.

After extensively expanding in monolayer culture, the cultured chondrocytes become quiescent. The aim of this study was to establish the hypothesis that the phenotypic function of extensively expanded primary chondrocytes may be restored with extracellular matrix (ECM) compositions with or without growth factors. The restoring effects of these microenvironmental factors on the near quiescent passage 9 (P9) chondrocyte were investigated. The data showed that exogenous type I collagen and type II collagen at 1 : 1 ratio stimulate cell proliferation greatly while type II collagen alone was enough to revive most of cartilaginous functions of near quiescent P9 chondrocytes. Exogenous type II collagen by itself was more effective in restoring cell proliferation rate, elevating glycosaminoglycan (GAG) accumulation and promoting the re-expression of type II collagen mRNAs in the near quiescent chondrocytes. The supplement of P9 chondrocytes with type II collagen plus TGF-β1 and IGF-I appeared essential for the re-expression of aggrecan and type II collagen mRNA in monolayer culture. In 3D type II collagen construct, P9 chondrocytes appeared healthy as chondrocytes and showed clear lacuna. However, in 3D type I collagen matrix, only some P9 chondrocytes exhibited lacuna. The cartilaginous microenvironments are crucial to restoring chondrocyte-phenotypic features of the quiescent or ‘dedifferentiated’ chondrocytes, implicating the potential of expanding a scarcity of healthy chondrocytes for cartilage repair or regeneration.

The effects of hardystonite (Ca₂ZnSi₂O₇, CSZn) and tricalcium phosphate (β-TCP) on the proliferation and osteogenic differentiation of human bone marrow-derived mesenchymal stem cells (MSCs) were compared by directly culturing MSCs on ceramic disks (contact mode) or separately culturing cells with ceramic disks (non-contact mode). In non-contact mode, the CSZn ceramic supported MSC proliferation more strongly than did the β-TCP ceramic. However, in contact mode, the MSCs proliferated more quickly on the β-TCP ceramic than they did on the CSZn ceramic. Alkaline phosphatase (ALP) staining and osteogenic gene expression analysis showed that the CSZn and β-TCP ceramics had significant effects on the promotion of the osteogenic differentiation of MSCs in both non-contact and contact mode. Furthermore, in contact mode, the CSZn disk promoted the osteogenic differentiation of MSCs more strongly than did the β-TCP disks. Even without the induction of dexamethasone and β-glycerophosphate, CSZn stimulated the osteogenic differentiation of MSCs. These results suggest that CSZn ceramic would be a useful candidate material for bone regeneration and hard tissue engineering.

Two different types of carbon coatings for cardiovascular applications were characterized both as regards to their physico-chemical properties and blood compatibility upon contact with human plasma and platelets. The samples were analyzed by means of a wide range of techniques, including scanning electron microscopy (SEM) and atomic force microscopy (AFM), contact angle goniometry, Raman spectroscopy and X-ray Diffraction (XRD). Multiple tests have been performed to evaluate plasma protein adsorption and platelets adhesion and activation, and to investigate possible correlations between the surface properties of the materials and their blood compatibility. We proposed a similar mechanism of blood/material interaction for the carbon-based materials tested. It has been suggested that the characteristic wettability and surface heterogeneity of the coatings guide protein adsorption and retention onto the carbon surfaces, promoting a preferential, extensive and tight adsorption of albumin molecules, that in turn leads to surface passivation and inhibits subsequent platelets adhesion and activation.

Osteogenic potential of biomaterials used in bone regenerative therapy has been mainly examined in an animal-implantation study. We have here evaluated the applicability of bone scintigraphy in imaging ectopic bone formation, especially its initial phase, by β-tricalcium phosphate (β-TCP) particles that were implanted in rat dorsal subcutaneous tissues. In implanted osteogenic osteosarcoma cells used as a positive control, osteoid formation was found by histological examination and bone scintigraphy using ^99mTc- hydroxymethyl diphosphonate (HMDP) at 2 and 3 weeks post-implantation, respectively, while the microfocus-computed tomography (µCT) system required further mineralization, which occurred at 4 weeks. Implantation of β-TCP particles alone induced only faint biomineralization inside the particles, which could be microscopically detected by calcein chelation at 2 weeks post-implantation, but not by other histological examinations (e.g., HE staining) or µCT. However, the bone scintigraphy successfully detected this microscopic change at 1 week. Implanted hydroxyapatite (HAp) particles alone used as a negative control did not induce mineralization at microscopic levels, and therefore nothing was detected by either calcein chelation or bone scintigraphy. In conclusion, the bone scintigraphic methodology, although exhibiting less quantitation and resolution, would be applicable as a non-invasive, highly sensitive methodology in detecting the initial, microscopic changes associated with mineralization.

Titanium and hydroxyapatite (HA) are widely used as biomaterials for dental and medical applications. HA-coated titanium implants have excellent biocompatibility and mechanical properties. However, the adherence of HA film formed on titanium substrate is weak because of the lack of chemical interaction between HA and titanium. A solution to this problem is to form an intermediate film on titanium substrate, which provide excellent adherence to both titanium substrate and HA. We developed a novel biomaterial called calcium titanate-amorphous carbon (CaTiO₃-aC) coating prepared by modified thermal decomposition method. The purpose of this study was to evaluate the effect of CaTiO₃-aC and HA coating (positive control), and Ti (negative control) on osteoblastic (MT3T3-E1) cell responses. An increased cellular proliferation was observed in CaTiO₃-aC coating compared to HA coating. The maximum expressions of ALP activity, Col I and ALP mRNA were higher and achieved in shorter period of time in CaTiO₃-aC coating compared to others. These results demonstrated that CaTiO₃-aC promoted better cell attachment, cellular proliferation, and osteoblastic differentiation compared with HA. In conclusion, we suggested that CaTiO₃-aC could be considered as an important candidate as a coating material.

Osteosarcoma is a primary malignant bone tumor, most prevalent in children and adolescents, and is usually highly aggressive and eventually lethal. Despite multimodal therapies, there is no effective approach to treat this malignant disease. In this study, we observed the biological response of osteosarcoma cells to two kinds of hydroxyapatite nanoparticles (Nano HA), NanoHA-S and NanoHA-L. These nanospheres have the same crystallinity (phase) and morphology, but they differ in size. Cells treated with two kinds of Nano HA were inhibited and mainly led to apoptotic cell death. Caspase-9-dependent intrinsic apoptotic pathway plays a role. It was interesting that the suppression and the apoptosis of osteosarcoma cells was directly related to the size of nanoparticles and that the larger-sized Nano HA exhibited more effectiveness than the smaller one. This in vitro study suggested the potential of size-controlled calcium phosphate nanoparticles for use in therapeutic replacement and reconstruction of bone merits after osteosarcoma extraction.

The properties of scaffolds and their roles in regulating functions of tissue cells are considered to be of utmost importance in the successful recovery of damaged tissues. Herein, novel scaffolds of collagen and bioactive inorganic nanofiller were produced for bone tissue engineering. In addition, the in vitro responses of bone marrow-derived stromal cells (BMSCs) on these scaffolds were investigated. Glasses with bioactive compositions were prepared in nanofibrous form and homogenized with a collagen to produce hybridized porous scaffolds. The glass fibrous filaments with diameters of a few hundred nanometers were embedded well within the collagen network, characterizing a typical nanocomposite. The scaffolds showed the characteristics of a hydrogel with remarkable water uptake and swelling degree, which were similar to those of the pure collagen. In addition, the scaffolds induced the precipitation of bone-like minerals on the surface under a body-simulating medium, showing the sign of in vitro bone bioactivity. BMSCs adhered and spread well over the scaffold surface and migrated deep into the scaffold network. The osteogenic marker, alkaline phosphatase, was strongly expressed on the hybrid scaffolds, with the level higher than that on pure collagen. Overall, the collagen–inorganic nanofiller scaffolds are considered to find potential utility in bone tissue engineering.

In the present work, we have investigated platelet microparticle (PMP) generation in whole blood after contact with nanoporous alumina. Alumina membranes with pore sizes of 20 and 200 nm in diameter were incubated with whole blood and the number of PMP in the fluid phase was determined by flow cytometry. The role of the complement system in PMP generation was investigated using an analog of the potent complement inhibitor compstatin. Moreover, the procoagulant activity of the two pore size membranes were compared by measuring thrombin formation. Results indicated that PMP were not present in the fluid phase after whole blood contact with either of the alumina membranes. However, scanning electron microscope micrographs clearly showed the presence of PMP clusters on the 200 nm pore size alumina, while PMP were practically absent on the 20 nm membrane. We probed no influence of complement activation in PMP generation and adhesion and we hypothesize that other specific material-related protein–platelet interactions are taking place. A clear difference in procoagulant activity between the membranes could also be seen, 20 nm alumina showed 100% higher procoagulant activity than 200 nm membrane. By combining surface evaluation and flow cytometry analyses of the fluid phase, we are able to conclude that 200 nm pore size alumina promotes PMP generation and adhesion while the 20 nm membrane does not appreciably cause any release or adhesion of PMP, thus indicating a direct connection between PMP generation and nanoporosity.

Complex fractures resulting in bone loss or impaired fracture healing remain problematic in trauma and orthopedic surgeries. Many bone graft substitutes have been developed and are commercially available. These products differ in their osteoconductive and osteoinductive properties. Differential enhancement of these properties may optimize the performance of these products for various orthopedic and craniofacial applications. The use of bone graft substitutes offers the ability to lessen the possible morbidity of the harvest site in autografts. The objective of the present study was to compare the ability of two bone graft substitutes, BioSet^® RT, an allograft demineralized bone matrix formulation, and ProOsteon^® 500R, a coralline hydroxyapatite, in a rabbit critical tibial defect model. BioSet^® RT and ProOsteon^® 500R were implanted into a unicortical proximal metaphyseal tibial defect and evaluated for new bone formation. Samples were analyzed radiographically and histologically at 1 day, 6 weeks, 12 weeks, and 24 weeks post surgery. Both materials were biocompatible and demonstrated significant bone growth and remodeling. At 12 weeks, the BioSet^® RT implanted sites demonstrated significantly more defect closure and bone remodeling as determined by radiographic analyses with 10 out of 14 defects being completely healed versus 1 out of 14 being completely healed in the ProOsteon^® 500R implanted sites. At 24 weeks, both materials demonstrated complete closure of the defect as determined histologically. There were no statistical differences in radiographic scores between the two implanted materials. However, there was an observable trend that the BioSet^® RT material generated higher histological and radiographic scores, although not statistically significant. This study provides evidence that both BioSet^® RT and ProOsteon^® 500R are biocompatible and able to induce new bone formation as measured in this rabbit model. In addition, this in vivo study demonstrates the ability of BioSet^® RT to induce new bone formation in a shorter timeframe than ProOsteon^®500R.

Dynamic mechanical properties under three-point bending and deformation behavior under indentation loading of an ultrahigh molecular weight polyethylene (UHMWPE) were investigated in this study. Dependence of its viscoelastic properties on temperature, frequency, load level, specimen geometry and heating rates were examined. The results showed that temperature and frequency had significant effects on the response of UHMWPE to the dynamic load. With the increase in temperature, the storage modulus (E') was decreased and the loss angle (tan ) was increased, indicating an increase in the trend in viscoelastic response of the polymer at high temperature. On the other hand, when frequency was increased, higher E' and lower tan were observed, suggesting that the material behaved more elastically. While the two heating rates of 5°C/min and 10°C/min had little effect on E' and tan , the load level significantly influenced the dynamic mechanical properties of the polymer. UHMWPE showed quite different responses at 0.5 and 20 Hz than at 1–10 Hz, which is worth further investigation. The results from indentation experiment showed that temperature, specimen geometry and load level had significant effects on the response of UHMWPE to the indentation load. With the increase in temperature, the penetration depth was increased, indicating an increase in the deformation trend in the polymer at high temperature. High load led to high penetration. The time-temperature superposition (TTS) method could be used to predict the long-term penetration behaviors of the polymer. From TTS analysis, the activation energy associated with penetration deformation was obtained. Further analysis showed that it might be possible to increase the resistance of UHMEPE to indentation deformation by increasing the thickness and/or decreasing the diameter of the polymer samples.

The aim of this research study is the preparation and characterization of graded glass–ceramic scaffolds that are able to mimic the structure of the natural bone tissue, formed by cortical and cancellous bone. The material chosen for the scaffolds preparation is a glass belonging to the system SiO₂–P₂O₅–CaO–MgO–Na₂O–K₂O (CEL2). The glass was synthesized by a conventional melting–quenching route, ground, and sieved to obtain powders of specific size. The scaffolds were fabricated using different methods: polyethylene burn-off, sponge replication, a glazing-like technique, and combinations of these methods. The scaffolds were characterized through morphological observations, density measurements, volumetric shrinkage, mechanical tests, and in vitro bioactivity tests. The features of the scaffolds prepared using the different methods were compared in terms of morphological structure, pores content, and mechanical strength. The proposed scaffolds effectively mimic the cancellous/cortical bone system in terms of structure, porosity, and mechanical strength, and they exhibit a highly bioactive behavior. Therefore, these graded grafts have a great potential for biomedical applications and can be successfully proposed for the substitution of load-bearing bone portions.

A thermosensitive polymer can be held liquid before being injected to deliver living cells or therapeutic agents and formed monolithic gels when injected in vivo. In this study, chitosan-based thermosensitive hydrogels were prepared, characterized and the biocompatibility for culturing mice bone mesenchymal stem cells (BMSC) on 2D films and within 3D hydrogel were investigated. The gelation temperature and biocompatibility could be modulated by addition hydroxyethyl cellulose (HEC) to chitosan–glycerophosphate (CH–GP) formulation. The CH–GP–HEC liquid solution can turn into gel at body temperature and has highly compatible with BMSC. Therefore, the CH–GP–HEC gel could be used as an attractive injected in-situ forming scaffold for future applications of delivering biologically active therapeutics for tissue engineering filed.

Human tympanic membrane cells (hTMCs), harvested from tympanic membrane (TM) explants, were grown in culture and then seeded on membranes prepared from silkworm (Bombyx mori) silk fibroin (BMSF) and on tissue-culture plastic membranes (PET). Fibroin was isolated from silk cast into membranes with a thickness of 10–15 µm. The hTMCs were cultured on both materials for 15 days in a serum-containing culture medium. The cells grown on both substrata were subjected to nuclear staining (DAPI) and counted. Further, the cultures were immunostained for a number of protein markers related to the epithelial/keratinocyte phenotype and cell adhesion complexes. The BMSF membranes supported levels of hTMC growth higher than that observed on the PET membranes. The immunofluorochemical analysis indicated unequivocally that BMSF is a more suitable substratum than PET with respect to the growth patterns, proliferation, and cell–cell contact and adhesion. BMSF appear as a promising substratum in the tissue-engineered constructs for the replacement of TM in case of nonhealing perforations.

The phenomenon of osteoinduction by biomaterials has been proven and used in animals. However, whether the ability of a biomaterial to initiate bone formation in ectopic implantation sites improves the performance of such osteoinductive biomaterial as a scaffold for tissue-engineered (TE) bone remains unclear. In this study, we compared ectopic bone formation by combining autologous adipose-derived stromal cells (ADSCs) with an osteoinductive and a nonosteoinductive biphasic calcium phosphate (BCP) ceramic to create a tissue engineering construct in the muscle of dogs. Two groups of BCP scaffolds (BCP1 and BCP2) were prepared. In each group, ADSCs were seeded, and the scaffolds without seeded cells served as controls. All implants were implanted in the back muscle of 10 adult dogs for 8 weeks and 12 weeks. Microcomputed tomography (Micro-CT) analysis and histomorphometry were performed to evaluate and quantify ectopic bone formation. The results indicated that the osteoinductive BCP1 performed significantly better compared to the nonosteoinductive BCP2 in cell-based TE bone formation ectopically. The ADSCs had a significantly positive effect on the ectopic bone formation. In addition, the usefulness of Micro-CT for the efficient and nondestructive analysis of mineralized bone and calcium phosphate scaffold was confirmed.

Recently, phosphate-based glass (PBG) fibers have been used to reinforce the biodegradable polymers polycaprolactone and polylactic acid, in order to fabricate materials suitable for use as resorbable bone fracture fixation devices. However, the PBG fibers investigated tended to degrade too quickly for application. Therefore, more durable PBG formulations were sought with emphasis remaining firmly placed on their biocompatibility. In this study, four invert PBG formulations (in the system P₂O₅–CaO–MgO–Na₂O) were produced with fixed phosphate and calcium content at 40 and 25 mol%, respectively. MgO was added at 10–30 mol% in place of Na₂O and the maximum divalent cation to phosphate ratio obtained was 1.375. Thermal analyses showed a linear increase in T_g with increasing MgO content. This was proposed to be due to an increase in the cross-link density of the glass network, which also improved the chemical durability of the glass. EDX analyses were also conducted to verify the final composition of the glass. XRD analyses confirmed the amorphous nature of the glasses investigated. Rapid quenching of the Mg30 glass revealed a degree of surface crystallization, which was shown to be a CaMgP₂O₇ phase. The degradation rates of the glasses investigated decreased with increasing MgO content. The decrease in rate seen was almost two orders of magnitude (a x50 difference was seen between glass Mg0 and Mg30). The cytocompatibility studies of the formulations investigated showed good cellular response over time for up to 14 days. Statistical analysis revealed that the formulations investigated gave a response comparable to the tissue culture plastic control. It is suggested that invert PBG provide degradation profiles and the cytocompatibility response desired to make these glasses useful for bone repair applications.

Poly (ethylene terephthalate) (PET) was surface modified by plasma polymerization of acetobromo--D-glucose (ABG) at different radio frequency (RF) powers. Plasma polymerization was carried out by vaporizing ABG in the powder form by heating at 135°C. Surface modification resulted in improved hydrophilicity and smoothness of the surface especially at low RF powers (30-50 W), but at high RF powers, the surface was found to be etched and the hydrophilicity decreased as evidenced by atomic force microscopy (AFM) and contact angle measurements. The plasma polymerized ABG film was found to be extensively cross-linked as evidenced by its insolubility in water. Infra red (IR) and X-ray photoelectron spectroscopy (XPS) were employed to characterize the plasma polymerized ABG films. IR studies revealed that at lower RF powers, polymerization was taking place mainly by breaking up of acetoxy group while retaining the ring structures to a major extent during the polymerization process whereas at high RF powers, the rupture of ring structures was indicated. XPS indicated a reduction in the percentage of oxygen in the polymers going from low to high RF powers suggestive of complete destruction of the acetoxy group at high RF powers. Cross-cut tests showed excellent adhesive properties of the plasma polymerized ABG films onto PET. Static platelet adhesion tests using platelet rich human plasma showed significantly reduced adhesion of platelets onto modified PET surface as evidenced by scanning electron microscopy. Polymerization of glucose and its derivatives using RF plasma has not been reported so far and the preliminary results reported in this study shows that this could be an interesting approach in the surface modification of biomaterials.

Intestinal fistula is associated with high morbidity and difficult to manage. Many fistulas require surgical treatment, which usually consists of segmental resection. In this study, using a rat model, the effectiveness of chitosan hydrogel as an intestinal fistula repair agent was investigated. Twenty rats underwent laparotomy under general anesthesia. The antimesentric portion of the cecum was incised (1 cm) and sutured to the abdominal wall. Chitosan hydrogel was applied daily to the fistula until it was completely closed. Blood samples taken from all animals were analyzed. After sacrifice, the cecum was removed and histopathologic investigation was performed. Spontaneous closure of the intestinal fistula was observed in all animals for both the control and chitosan hydrogel groups. Healing in the chitosan hydrogel group healing was faster than that in the control group. Blood analysis revealed significant differences between the chitosan hydrogel and control groups with regard to the total protein, albumin, total cholesterol and HDL before the surgery versus that on the day of sacrifice. Pathologic investigation also showed greater healing in the chitosan hydrogel group than the control group. This preliminary study showed the potential of chitosan hydrogel for repair of intestinal fistula. However further studies must be performed before we can approve testing chitosan hydrogel for intestinal fistula repair in humans.

A series of cellulose/soy protein isolate (SPI) sponges was prepared using a freeze-drying process. The effect of the SPI content on?the?structure of the sponges was characterized by Fourier transform infrared?spectrometry (FT-IR), X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). It showed that the sponges were porous in?structure,?and?that the size of the pores increased and the thickness of?the?pore walls?decreased as the SPI content of the sponges increased. The?biocompatibility and?biodegradability of the sponges were evaluated in?vitro in vivo. The?cell?culture experiment and SEM observations showed?that?L929 fibroblast?cells grew and spread well on the?surface?and?cross-section of?the?composite sponges. The results from MTT (3-[4,5-dimethyl-2-thiazoly1]-2,5-diphenyl-2H-tetrazolium bromide) assay indicated that the cell?viability of L929 cultured in extracts from SPI-containing sponges was higher than that from the pure cellulose sponge. The historical analysis and SEM observation revealed that the SPI-containing sponges implanted from 1?to?8 months in rats exhibited better in vivo biocompatibility and biodegradability than the pure cellulose sponge. This?was?due to the incorporation of SPI into cellulose and to the freeze-drying process which formed large pores and thin?pore walls in the composite sponges, promoting the migration of cells and tissue into the sponges, leading to gradual fusing with the?implants. The new cellulose/SPI sponges thus have potential applications as biomaterials with good biocompatibility and biodegradability.

Fatigue testing for twelve SG tubular fabrics with various textile parameters was performed under pulsatile pressure by an Accelerated fatigue tester. Two time points as of 0, and 1 x 10⁸ cycles were selected. The percentage change of tubular diameter, fabric count, porosity, and water permeability before and after the fatigue testing were used to characterize the fatigue performance. Bursting work was used to indicate fatigue. The mathematical model of quantification theory I was used to analyze the influence of various textile parameters on the fatigue performance of SG tubular fabric. It was found that with the increase of fatigue time, bursting work decreased, and the predicting results by quantification theory I for the fatigue resistance were relatively accurate and the contribution ratio of each textile parameter to the fatigue performance was also obtained. Different textile parameter has different contribution ratio if different parameters were used to characterize the fatigue performance. Woven construction had more influence than yarn size on the =-0.2pt>fatigue performance, and yarn type had the least influence on it. Woven construction, yarn size, and yarn type had interactive influence on the fatigue performance. This can provide theoretical foundation for making better fatigue resistant SG tubular fabrics.

Glass Polyalkenoate Cements (GPCs) based on strontium calcium zinc silicate (Sr-Ca-Zn-SiO₂) glasses and high molecular weight poly(acrylic acid) (PAA) have been shown to exhibit suitable mechanical properties for orthopaedic arthroplasty applications, however for vertebroplasty and other medical luting applications these cements have working and setting times which are unsuitable for such applications. In this study GPCs based on Sr-Ca-Zn-SiO₂ glasses and low molecular weight PAA were evaluated for orthopaedic luting applications. GPCs based on four different glasses; BT100 (0.16CaO, 0.36ZnO, 0.48SiO₂), BT101 (0.04SrO, 0.12CaO, 0.36ZnO, 0.48SiO₂), BT102 (0.08SrO 0.08CaO, 0.36ZnO, 0.48SiO₂) and BT103 (0.12SrO 0.04CaO, 0.36ZnO, 0.48SiO₂) and two PAAs (MW; 12,700 and 25,700) were examined. These cement formulations exhibited handling properties potentially suitable for luting applications as well as mechanical strengths which were similar to those of trabecular bone. Upon immersion in simulated body fluid, the GPCs showed sustained growth of a calcium phosphate layer on the surface of the cement indicating that these cements were bioactive in nature.

Restenosis following percutaneous coronary intervention (PCI) is a considerable problem in long-term performance of cardiovascular stents, with a functional endothelial cell monolayer being important in its prevention. This study evaluates the influence of polymer coatings on human aortic endothelial cells (HAEC) and coronary artery smooth muscle cells (HCASMC) in vitro, in terms of morphology, cell number, and phenotype. It was demonstrated that the polymer coatings can be tailored to enhance adhesion and growth of HAECs whilst suppressing that of HCASMCs. It is concluded that one of the polymer coatings (BTL 01015) shows potential as a stent coating to enhance re-endothelialization.

Resin luting agents in which bisphenol-A glycidyl dimethacrylate (Bis-GMA) and/or triethylene glycol dimethacrylate (TEGDMA) are replaced with increasing amounts of bisphenol-A ethoxylated dimethacrylate are prepared. Degree of conversion (DC), diametral tensile strength (DTS), Young's modulus (YM), Knoop hardness (KHN), film thickness (FT), water sorption (W_sp), and solubility are evaluated. Regression analyses investigate the substitution of each monomer. The most appreciable differences are detected when TEGDMA is replaced: decreased DC, DTS, and W_sp, and increased YM, KHN, and FT. For substitution of Bis-GMA, the only significant differences are reduced W_sp and increased YM. An ideal formulation of resin cement would make use of the three monomers.

We have developed a novel glass-ionomer cement system composed of multi-arm poly(acrylic acid-co-itaconic acid)s. These polyacids were synthesized via a chain-transfer polymerization reaction using newly synthesized multi-arm chain-transfer agents. The cements formulated with the multi-arm polyacids showed significantly lower viscosities in water as compared to those formulated with the linear polyacids. Due to the lower viscosities, the MW of the polyacids can be significantly increased for enhanced mechanical strengths, while keeping the ease of mixing and handling. The experimental cements showed significantly improved compressive strengths as compared to Fuji II after aged in water for 3 months.

Porous scaffolds play an integral role in many tissue-engineering approaches, and the ability to improve vascularization, without eliciting an excessive inflammatory response, would constitute an important step towards achieving long-term healing and function of devices made from these materials. After having previously optimized the dimensional requirements of the well-defined pores, the present study aimed at a further shift from inflammation to vascularization via surface immobilization with heparin. Porous polyurethane disks were produced to contain well-defined pores (147 ± 2 µm) with abundant interconnecting windows (67 ± 2 µm). After heparinization via copolymer grafting and amination to contain 32 µg of heparin, the modification appeared as a uniform layer on all exposed surfaces, with no signs of pore obliteration or significant changes in pore size. After 28 days implantation in a rat subcutaneous model, the scaffolds were assessed for vascularization/arteriolization and inflammation using CD31/actin and ED-1 staining, respectively. Heparinization resulted in a significant increase in vascularization: capillaries increased by 62% in number (66.2 ± 0.8 to 107.3 ± 1.4 vessels/mm²; p<0.03) and 56% in total area (0.9 ± 0.1 to 1.4 ± 0.02%; p<0.02). Arteriolization also increased in absolute terms (200% in number; p<0.03), but did not change significantly when normalized to capillary number. Heparinization did not significantly affect the inflammatory response at this time-point, as quantified by ED-1 positive macrophage and foreign body giant cell (FBGC) content. Thus, the in vivo vascularization of porous scaffolds could be increased without concomitant increase in the inflammatory response by employing a simple surface modification technique. This could be a valuable tool for in vivo tissue engineering applications where enhanced vascularization is required.

Allograft tissues are used in over one million musculoskeletal procedures per year. Consequently, it is crucial tissue banks use procedures to militate against allograft associated bacterial and viral infections. Recent studies have identified an important pathogen inactivation technology for musculoskeletal allografts that utilizes high-dose gamma irradiation (50 kGy) under controlled conditions. A total dose of 50 kGy assures that the current standard for medical devices for a microbial sterility assurance level of 10^-6 is met. Furthermore, the pathogen inactivation technology results in a greater than four log inactivation of enveloped and nonenveloped viruses. Efficacious clinical outcome from musculoskeletal allografts exposed to this innovative sterilization procedure will require that there is no performance decrement in the allograft's biological properties. Therefore, to validate this objective, we executed a study focusing on remodeling and osteoconduction of bone allografts treated with a high dose of gamma irradiation (50 kGy), radioprotectants and well-defined operating parameters of temperature and water content. A rabbit calvarial model was used to test the hypothesis that remodeling and osteoconduction of allogeneic bone treated with the new pathogen inactivation technology would be equivalent to nontreated allogeneic bone. Results indicated treated bone allografts were comparable to nontreated allografts. We conclude, therefore, that based on this outcome and other reports, that high doses of gamma irradiation under optimized conditions designed to reduce free radical damage to tissue will provide safer allografts.