Journal of biomedical materials research. Part B, Applied biomaterials最新文献

A biodegradable, shape memory polymer (SMP) scaffold based on poly(ε-caprolactone) (PCL) represents an attractive alternative therapy for the repair of critically sized bone defects given its ability to press-fit within irregular defects. Clinical translation of SMP scaffolds requires successful movement beyond proof-of-concept rodent studies through a relevant large-animal model and into the clinical setting. In addition to representing a clinical veterinary population, the canine species is a strong translational model for humans due to similarities in orthopedic disorders, biomechanics, and bone healing. The present study was performed to assess in vitro cytocompatibility and osteogenic differentiation of canine multipotent stromal cells (cMSCs) cultured on SMP scaffolds in preparation for future canine in vivo studies. Two different SMP scaffold compositions were utilized: a “PCL-only” scaffold prepared from PCL-diacrylate (PCL-DA) and a semi-interpenetrating network (semi-IPN) formed from PCL-DA and poly(L-lactic acid) (PCL:PLLA). The PCL:PLLA scaffolds degrade faster and are more mechanically rigid versus the PCL scaffolds. Canine bone marrow–derived MSCs (cMSCs) were evaluated in terms of attachment, proliferation, and osteogenic differentiation. cMSCs exhibited excellent cytocompatibility, attachment, and proliferation on both SMP scaffold compositions. PCL scaffolds were more conducive to both early- and late-stage in vitro osteogenesis of cMSCs versus PCL:PLLA scaffolds. However, cMSCs deposited mineralized extracellular matrix over 21 days when cultured on both SMP scaffold compositions. These results demonstrate that the SMP scaffolds are suitable for in vitro cMSC attachment, proliferation, and osteogenic differentiation, representing a significant step toward canine in vivo studies and potential translation to human patients.

Melt-blown, an environmentally friendly technique, is widely used to create high-quality non-woven fabrics by extruding molten polymer resins into interlaced fibers. In the realm of biomedical textiles, its unique microstructure makes it ideal for filtration and wound dressings. Our study focuses on modifying the surfaces of polypropylene melt-blown membranes. An effective, one-step, suitable, and reliable method to graft a bioactive polymer, sodium polystyrene sulfonate—PolyNaSS, onto the membranes has been developed. The process involves UV irradiation to initiate direct and progressive growth of NaSS over the surface through radical polymerization. To assess the efficiency of the grafting, techniques like colorimetry, water contact angle measurements, Fourier-transformed infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) were used. Outcomes related to the grafting were demonstrated by a change in wettability and quantitatively calculated sulfonate groups. Subsequently, grafted PolyNaSS promoted cell adhesion, as evidenced by improved cell morphology. On grafted membranes, fibroblasts exhibited a stretched shape, while non-grafted ones showed inactive round shapes. These findings underscore the chemical and biological reactivity of polypropylene materials, opening exciting possibilities for various applications of melt-blown materials.

Zinc oxide nanoparticles are known to possess anti-inflammatory, antibacterial, and antiseptic properties and find wide application in the preparation of topical ointments. Wound dressings in the form of hydrogels can replenish the wound microenvironment to aid the healing process in a multidimensional way. We have fabricated a composite hydrogel using 1–3 wt. % ZnO nano-particles, synthesized by chelation reaction, and poly-2-hydroxyethyl methacrylate (pHEMA)/acrylamide, synthesized, and co-polymerized in 8 kGy gamma irradiation. Developed powders and composite membranes have been thoroughly analyzed for XRD, FTIR, SEM–EDX mapping, DTA/TGA, particle size, shape, morphology, porosity, water uptake, and contact angle. Thermally stable phase-pure ZnO spherical nanoparticles with an average crystallite size of 40 ± 2 nm have been used for fabricating well-dispersed composite with contact angle varying 78^o–88^o. These membranes, when used in vivo, rendered a suitable environment conducive to tissue regeneration and ECM component deposition sequentially. Endowed with antibacterial properties, these hydrogels also demonstrated excelling swelling capacity which proved beneficial in maintaining a moist wound environment aiding in the healing process. An earlier wound closure was achieved with 2%–3% ZnO-pHEMA/acrylamide hydrogels which demonstrate the potential of ZnO nanoparticles in signaling and instructing the wound bed milieu towards the efficient repair.

The integration of electrically conductive materials is a promising approach in tissue regeneration research. The study presented focuses on the creation of electroconductive scaffolds made from polypyrrole-polycaprolactone (PPy-PCL) using optimal processing parameters. Utilizing Box–Behnken response surface methodology for in situ chemical polymerization of PPy, the scaffolds exhibited a maximum conductivity of 2.542 mS/cm. Morphological examination via scanning electron microscopy (SEM) indicated uniform dispersion of PPy particles within PCL fibers. Fourier transform infrared spectroscopy (FTIR) and energy dispersive x-ray (EDX) analysis validated the composition of the scaffolds, while mechanical testing revealed that the optimized scaffolds exhibit superior tensile strength and Young's modulus compared to scaffolds comprised only of PCL. The hydrophilicity of the scaffolds was improved considerably, transitioning from initially hydrophobic to fully hydrophilic for the optimum scaffold, making it suitable for tissue engineering applications. Cell viability assays, including MTT with L929 fibroblasts and Alamar Blue with bone marrow mesenchymal stem cells (bmMSCs), reflected no cytotoxicity. They showed an increase in metabolic activity, suggesting the capability of the scaffolds to support cellular functions. In conclusion, the in situ synthesis of PPy in the PCL matrix by optimizing the fabrication parameters resulted in conductive scaffolds with promising structural and functional properties for tissue engineering.

The ASTM F2888-19 standard for platelet and leukocyte count assay is the only standardized test method for assessing platelet and leukocyte interactions with blood-contacting device materials. This study aimed to address two limitations of the ASTM F2888-19 standard: low test sensitivity for leukocyte count and high test sample surface area to blood ratio (12 cm²/mL). Human blood from healthy adult donors was drawn into polypropylene tubes with either 3.2% sodium (Na) citrate or anticoagulant citrate dextrose solution A (ACDA). Immediately before starting the test, the blood was recalcified and heparinized to a concentration of 1, 1.5, or 2 U/mL and incubated with the test materials of varying thrombogenic potential at an exposure ratio of 6 or 12 cm²/mL for 1 h at 37°C ± 2°C in a shaking water bath. Complete blood count was measured using a hematology analyzer. The results show that both, Na-citrated blood (6 or 12 cm²/mL exposure ratio) and ACDA blood (6 cm²/mL ratio), were able to differentiate thrombogenic materials from commonly used biomaterials based on platelet count changes. The magnitudes of difference between the thrombogenic materials and biomaterials depends on heparin concentration. The test sensitivity was highest when ACDA blood, heparinized to 1 U/mL heparin, was used. Moreover, the use of ACDA blood, unlike Na-citrated blood, also allowed the assay to distinguish between the thrombogenic materials from commonly used biomaterials based on leukocyte count changes. In conclusion, the use of ACDA blood significantly increased test sensitivity of the ASTM F2888-19 test method in differentiating materials with varying thrombogenicity based on both platelet and leukocyte counts, while reducing blood exposure ratio to 6 cm²/mL. These findings will be used to revise the ASTM F2888 standard in the future.

The adhesion strength of a bacterial strain on a substrate influences colonization and biofilm development, so the biomolecular analysis of this interaction is a step that allows insights into the development of antifouling surfaces. As peri-implantitis is the main cause of failure of implant-supported oral rehabilitations and the dental literature presents gaps in the atomic bacteria/surface interaction, this study aimed to correlate the qualitative variation of roughness, wettability, chemical composition, and electrical potential of Ti-6Al-4V and Ti-35Nb-7Zr-5Ta (TNZT) disks obtained by machining (M) and additive manufacturing (AM) on the colonization and adhesion strength of S. aureus quantified by atomic force microscopy (AFM). The samples were evaluated for roughness, electrical potential, and S. aureus colonization and adhesion strength by specific methods in the AFM with subsequent analysis in the NanoScope software analysis, wettability by sessile drop method, and chemical composition by energy dispersive x-ray spectroscopy (EDX). Qualitative data were correlated with bacterial adhesion strength. The greater adhesion strength of S. aureus was observed in descending order for TNZT AM, TNZT M, Ti-6Al-4V AM, and Ti-6Al-4V M. This experimental in vitro study allowed us to conclude that for the evaluated groups, the strength adhesion of S. aureus showed a linear relationship with roughness, and nonlinear for wettability, electrical potential, and S. aureus colonization on the surfaces evaluated. As for the two variation factors, type of alloy and manufacturing method, those that promoted the lowest bacterial adhesion strength were Ti-6Al-4V and M, possibly attributed to the synergistic modification of the evaluated surface properties. Thus, this study suggests S. aureus preferences for rough, hydrophilic surfaces with a greater electrical potential difference.

Bone-on-a-chip (BOC) models that based on microfluidic technology have widely applied to understand bone physiology and the pathogenesis of related diseases. In this review, we provide an overview of bone biology and related diseases, explain the advantages and applications of microfluidic technology in the construction of BOC models, and summarize their progress in physiology, pathology, and drug development. Finally, we discussed the problems to be solved and the future directions of microfluidic technology and BOC platforms, so as to provide a reference for researchers to design better BOC models.