Cementless fixation for orthopedic implants aims to obviate challenges associated with bone cement, providing long-term stability of bone prostheses after implantation. The application of porous titanium and its alloy-based implants is emerging for load-bearing applications due to their high specific strength, low stiffness, corrosion resistance, and superior osteoconductivity. In this study, coagulant-assisted foaming was utilized for the fabrication of porous TiAl V using egg-white foam. Samples with three different porosities of 68.3%, 75.4%, and 83.1% and average pore sizes of 92, 178, and 297 μm, respectively, were prepared and subsequently characterized for mechanical properties, osteogenesis, and tissue ingrowth. A microstructure-mechanical properties relationship study revealed that an increase of porosity from 68.3 to 83.1% increased the average pore size from 92 to 297 μm with the subsequent reduction of compresive strength by 85% and modulus by 90%. Samples with 75.4% porosity and a 178 μm average pore size produced signifcant osteogenic effects on human mesenchymal stem cells, which was further supported by immunocytochemistry and real-time polymerase chain reaction data. Quantitative assessment of bone ingrowth by micro-computed tomography revealed that there was an approximately 52% higher bone formation and more than 90% higher bone penetration at the center of femoral defects in rabbit when implanted with TiAl V foam (75.4% porosity) compared to the empty defects after 12 weeks. Hematoxylin and eosin (H&E) and Masson trichrome (MT) staining along with energy-dispersive X-ray mapping on the sections obtained from the retrieved bone samples support bone ingrowth into the implanted region.
Regeneration of full-thickness wounds without scar formation is a multifaceted process, which depends on in situ dynamic interactions between the tissue-engineered skin substitutes and a newly formed reparative tissue. However, the majority of the tissue-engineered skin substitutes used so far in full-thickness wound healing cannot mimic the natural extracellular matrix (ECM) complexity and thus are incapable of providing a suitable niche for endogenous tissue repair. Herein, we demonstrated a simple approach to fabricate porous hybrid ECM sponges (HEMS) using a placental ECM and silk fibroin for full-thickness wound healing. HEMS with retained cytokines/growth factors provided a noncytotoxic environment in vitro for human foreskin fibroblasts (HFFs), human epidermal keratinocytes (HEKs), and human amniotic membrane-derived stem cells to adhere, infiltrate, and proliferate. Interestingly, HEMS-conditioned media accelerated the migration of HFFs and HEKs owing to the presence of cytokines/growth factors. Also, the ex vivo chick chorioallantoic membrane assay of HEMS demonstrated its excellent vascularization potential by inducing and supporting blood vessels. Additionally, HEMS when subcutaneously implanted demonstrated no severe immune response to the host. Furthermore, HEMS implanted in full-thickness wounds in a rat model showed augmented healing progression with well-organized epidermal-dermal junctions via pronounced angiogenesis, accelerated migration of HFFs/HEKs, enhanced granulation tissue formation, and early re-epithelialization. Taken together, these findings show that porous HEMS ornamented with cytokines/growth factors having superior physicomechanical properties may be an appropriate skin substitute for full-thickness cutaneous wounds.
Macroporous hydrogel monoliths having tailor-made features, conductivity, superstretchability, excellent biocompatibility, and biodegradability, have become the most nurtured field of interest in soft biomaterials. Green method assisted reduced graphene oxide has been inserted by in situ free radical gelation into semi-IPN hydrogel matrix to fabricate conducting hydrogel. Mechanical toughness has been implemented for the graphene-polymer physisorption interactions with graphene basal planes. Moreover, the as-prepared 3D scaffold type monolith hydrogel has been rheologically superior regarding their high elastic modulus and delayed gel rupturing. κ-Carragenaan, one of the components of the hydrogel, has biodegradable nature. The most significant outcome is their low electrical percolation threshold and reversibly ductile nature. Reversible ductility provides them with rubber-like consistency in flow conditions. Surprising, the hydrogels showed dual stimuli-responsiveness, that is, environmental pH and external electrical stimulation. Electro-stimulation has been adopted here for the first time in semi-IPN systems, which could be an ideal alternative for iontopheretic devices and pulsatile drug release through skin. Regarding this, the hydrogel also has been passed to biocompatibility assay; they are noncytotoxic and show cell proliferation without negligible cell death in live-dead assay. The porosity of the nanocomposite scaffold-like gels was also analyzed by microcomputed tomography (μ-CT), which exhibited their connectivity in cell/voids inside the matrix. Thus, the experimentations are on the support of biocompatible soft material for dual-responsive tunable drug delivery.
A convenient procedure has been developed for the synthesis of styrenyl selenocyanates and benzoselenophenes from readily available styrenyl bromides by reaction with potassium selenocyanate in the presence of iodine under specified conditions. A series of both compounds have been obtained by this procedure. The synthesis of styrenyl selenocyanates has not been previously reported, and thus this method is of much significance.
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