Kara M. HarpePierre P. D. KondiahPradeep KumarPhilemon Ubanako...
22页
查看更多>>摘要：Abstract In this research, a novel bioabsorbable suture that is, monofilament and capable of localized drug delivery, was developed from a combination of natural biopolymers that where not previously applied for this purpose. The optimized suture formulation comprised of sodium alginate (6% wt/vol), pectin (0.1% wt/vol), and gelatin (3% wt/vol), in the presence of glycerol (4% vol/vol) which served as a plasticizer. The monofilament bioabsorbable sutures where synthesized via in situ ionic crosslinking in a barium chloride solution (2% wt/vol). The resulting suture was characterized in terms of mechanical properties, morphology, swelling, degradation, drug release, and biocompatibility, in addition to Fourier‐transform infrared (FTIR) spectroscopy, Powder X‐ray Diffraction (PXRD) and Differential Scanning Calorimetry (DSC) analysis. The drug loaded and non‐drug loaded sutures had a maximum breaking strength of 4.18 and 4.08 N, in the straight configuration and 2.44?N and 2.59?N in the knot configuration, respectively. FTIR spectrum of crosslinked sutures depicted Δ9?cm?1 downward shift for the carboxyl stretching band which was indicative of ionic interactions between barium ions and sodium alginate. In vitro analysis revealed continued drug release for 7?days and gradual degradation by means of surface erosion, which was completed by day 28. Biocompatibility studies revealed excellent hemocompatibility and no cytotoxicity. These results suggest that the newly developed bioabsorbable suture meets the basic requirements of a suture material and provides a viable alternative to the synthetic polymer sutures that are currently on the market.
Jun IwatsuMunenori WatanukiShinichirou YoshidaShin Hitachi...
6页
查看更多>>摘要：Abstract Hydroxyapatite/collagen (HAp/col) has been reported to be a highly useful bone‐like nanocomposite. This study included 33 human patients to investigate the details of the clinical outcomes, which are (1) onset of timing of bone regeneration, (2) replacement by regenerated bone of HAp/col and (3) complications, in human cases grafting HAp/col in large bone defects, following curettage of bone tumors. Porous HAp/col initiated bone regeneration approximately 59?days following the surgery. In 15 cases (45%), complete replacement by newly formed bone was observed 12?months after surgery. On the other hand, incomplete replacement of HAp/col at the final follow‐up was observed in 13 cases (39%). In these cases, HAp/col could not be detected in the transparent area of postoperative plain radiographs owing to quick absorption; moreover, it was difficult to distinguish whether the transparent area in plain radiographs was remaining HAp/col, recurrence, or remaining tumor. In addition, larger HAp/col implantation volume (≧15?cm3) was associated with poorer result of complete replacement (log‐rank, p?=?.005). Further studies are warranted for the construction of a new artificial bone graft substitute that is more quickly and surely regenerated by newly formed bone in large bone defects.
Ali ZeraatkarAliakbar JafariLokman UzunShahrokh Shojaei...
14页
查看更多>>摘要：Abstract Nanocomposites containing clay nanoparticles often present favorable properties such as good mechanical and thermal properties. They frequently have been studied for tissue engineering (TE) and regenerative medicine applications. On the other hand, poly(glycerol sebacate) (PGS), a revolutionary bioelastomer, has exhibited substantial potential as a promising candidate for biomedical application. Here, we present a facile approach to synthesizing stiff, elastomeric nanocomposites from sodium‐montmorillonite nano‐clay (MMT) in the commercial name of Cloisite Na+ and poly(glycerol sebacate urethane) (PGSU). The strong physical interaction between the intercalated Cloisite Na+ platelets and PGSU chains resulted in desirable property combinations for TE application to follow. The addition of 5% MMT nano‐clay resulted in an over two‐fold increase in the tensile modulus, increased the onset thermal decomposition temperature of PGSU matrix by 18°C, and noticeably improved storage modulus of the prepared scaffolds, compared with pure PGSU. As well, Cloisite Na+ enhanced the hydrophilicity and water uptake ability of the samples and accelerated the in‐vitro biodegradation rate. Finally, in‐vitro cell viability assay using L929 mouse fibroblast cells indicated that incorporating Cloisite Na+ nanoparticles into the PGSU network could improve the cell attachment and proliferation, rendering the synthesized bioelastomers potentially suitable for TE and regenerative medicine applications.
查看更多>>摘要：Abstract Scaffold design is particularly important and necessary for soft tissue repair such as nerve tissue repair. In this article, we designed and manufactured a macroporous chitosan‐based hydrogel with excellent cell compatibility and antioxidant properties. Here, the chitosan (CS) based hydrogel is obtained by repeated freezing and thawing using citric acid (CA) as a cross‐linking agent. We have evaluated the effects of citric acid content on the physical and chemical properties of hydrogels through mechanical properties and scanning electron microscopy. CA‐CS hydrogel shows a macroporous structure, as the citric acid increases, the mechanical strength increases and the pore size decreases. In vitro cell experiments show that CA‐CS hydrogel partakes positive effects on cell survival, adhesion and proliferation, as well as antioxidant properties. All results provide a basis for the construction of porous chitosan‐based hydrogels, while demonstrating a promising approach to deal with oxidative stress in nerve injury.
Hooman Golbaten‐MofradMohammad Hadi SalehiSeyed Hassan JafariVahabodin Goodarzi...
17页
查看更多>>摘要：Abstract This study has attempted to systematically investigate the influence of nanoclay and graphene oxide (GO) on thermal, mechanical, hydrophobic, and, most importantly, biological properties of poly(glycerol sebacate)/gelatin (PGS/gel) nanocomposites. The PGS/gel copolymer nanocomposites were successfully synthesized via in situ polymerization, approved by rudimentary characterization methods. The nanofillers were appropriately dispersed within the elastomeric matrix according to morphological studies. Also, the fillers posed as a hydrophobic entity that slightly decreased the hydrophilic properties of PGS/gel. This could be sensed clearly in hybrid composite due to the robust network of GO and clay. Water contact angle values for gelatin‐contained nanocomposites were reported in the range of 38.42° to 66.7°, indicating the hydrophilic nature of the prepared samples. Thermal and mechanical studies of nanocomposites displayed rather contradicting results as the former improved while a slight decrease in the latter was noticed compared to the pristine specimens. In dry conditions, their storage modulus was in the range of 0.94–6.4?MPa, making them suitable for mimicking some soft tissues. The swelling ratio for nanocomposites containing nanoparticles was associated with an ascending trend so that GO improved the swelling rate by up to 45%. Biological analyses, such as Ames and in vitro cell viability tests, exhibited promising outcomes. As for the mutagenesis effect, the PGS and hybrid samples showed negative results. The presence of functional groups on the nanofillers' surface positively influenced the cells' metabolic activity as well as its attachment to the matrix. After 7?days, the cell proliferation rate resulted in an 82% improvement for the GO‐containing nanocomposite, significantly higher than its neat counterpart (65%). This study has shown the feasibility of the prepared bio‐elastomer nanocomposites for diverse tissue engineering applications.
Jacqueline H. ColeYihan HuangEdwin R. CadetMartin W. King...
8页
查看更多>>摘要：Abstract Polyvinylidene fluoride (PVDF) has been considered as an alternative suture material to replace polypropylene (PP) due to its superior biocompatibility and mechanical properties, but it has never been examined for use in barbed sutures, particularly for tendon repair. This study fabricated size 2–0 PVDF and PP bidirectional barbed sutures and compared their mechanical properties and anchoring performance in patellar tendons. The mechanical properties were evaluated via tensile testing, and the anchoring performance of the barbed sutures was assessed by a tendon suture pullout test. Sixty porcine patellar tendons were harvested, transected to mimic a full‐thickness injury, and repaired using a cross‐locked cruciate suturing technique. The ultimate tensile force was 60% higher for the PVDF barbed sutures (22.4?±?2.1?N) than for the PP barbed sutures (14.0?±?1.7?N). The maximum pullout force was 35% higher for PVDF barbed sutures (70.8?±?7.8?N) than for PP barbed sutures (52.4?±?5.8?N). The force needed to form a 2‐mm gap, indicative of repair failure, was similar between the PVDF (29.2?±?5.0?N) and PP (25.6?±?3.1?N) barbed sutures, but both were greater than the 2‐mm‐gap forces for non‐barbed sutures of the same size. In this study, PVDF barbed sutures provided better mechanical properties and improved tissue anchoring performance compared to the barbed PP sutures for porcine patellar tendon repair, demonstrating that PVDF monofilament sutures can be barbed and used effectively for tendon repair.
Yuxin ZengZeyi GuanChase S. LinsleyShuaihang Pan...
10页
查看更多>>摘要：Abstract Bioabsorbable metals are increasingly attracting attention for their potential use as materials for degradable implant devices. Zinc (Zn) alloys have shown great promises due to their good biocompatibility and favorable degradation rate. However, it has been difficult to maintain an appropriate balance among strength, ductility, biocompatibility, and corrosion rate for Zn alloys historically. In this study, the microstructure, chemical composition, mechanical properties, biocompatibility, and corrosion rate of a new ternary zinc?iron–silicon (Zn–Fe–Si) alloy system was studied as a novel material for potential biodegradable implant applications. The results demonstrated that the in situ formed Fe–Si intermetallic phases enhanced the mechanical strength of the material while maintaining a favorable ductility. With Fe–Si reinforcements, the microhardness of the Zn alloys was enhanced by up to 43%. The tensile strength was increased by up to 76% while elongation to failure remained above 30%. Indirect cytotoxicity testing showed the Zn‐Fe‐Si system had good biocompatibility. Immersion testing revealed the corrosion rate of Zn–Fe–Si system was not statistically different from pure Zn. To understand the underlying phase formation mechanism, the reaction process in this ternary system during the processing was also studied via phase evolution and Gibbs free energy analysis. The results suggest the Zn–Fe–Si ternary system is a promising new material for bioabsorbable metallic medical devices.
Ashley A. Stratton‐PowellSophie WilliamsJoanne L. TipperAnthony C. Redmond...
14页
查看更多>>摘要：Abstract Submicron‐sized wear particles are generally accepted as a potential cause of aseptic loosening when produced in sufficient volumes. With the accelerating use of increasingly wear‐resistant biomaterials, identifying such particles and evaluating their biological response is becoming more challenging. Highly sensitive wear particle isolation methods have been developed but these methods cannot isolate the complete spectrum of particle types present in individual tissue samples. Two established techniques were modified to create one novel method to isolate both high‐ and low‐density materials from periprosthetic tissue samples. Ten total hip replacement and eight total knee replacement tissue samples were processed. All particle types were characterized using high resolution scanning electron microscopy. UHMWPE and a range of high‐density materials were isolated from all tissue samples, including: polymethylmethacrylate, zirconium dioxide, titanium alloy, cobalt chromium alloy and stainless steel. This feasibility study demonstrates the coexistence of mixed particle types in periprosthetic tissues and provides researchers with high‐resolution images of clinically relevant wear particles that could be used as a reference for future in vitro biological response studies.
Alexander T. BooteDavid J. DeehanKenneth S. RankinDavid C. Swailes...
9页
查看更多>>摘要：Abstract Flanged acetabular cups were developed with the rationale that, at insertion, they would increase the pressure of the cement and improve penetration of cement into the acetabular bone. Various studies have been inconclusive regarding their effectiveness. In this work, we aimed to eliminate all confounding factors and measure the pressures generated during acetabular pressurization and cup implantation using a simplified steel acetabulum, high precision pressure transducers, proper surgical techniques and two acetabular cups, identical apart from the addition of a flange to one. It was found that the flanged acetabular component did not significantly increase the pressure in the acetabulum and in some cases reduced the pressures generated when compared to an unflanged cup. The addition of a flange did not reduce the pressure differential between the pole and the rim of the acetabulum, nor did it have a significant effect on pressure lost over the cup implantation period. It was concluded that flanged acetabular cups provide no significant improvement in the pressures generated in the acetabulum during acetabular cup implantation. It is hypothesized that the flange may be seen as a design feature intended to slow the insertion of the cup into the cement, thus requiring the surgeon to apply a larger load in order to correctly position the acetabular cup; in this way larger pressure will be generated.
NSTL
Wiley