Over the last few years, biopolymers have attracted great interest in tissue engineering and regenerative medicine due to the great diversity of their chemical, mechanical, and physical properties for the fabrication of 3D scaffolds. This review is devoted to recent advances in synthetic and natural polymeric 3D scaffolds for bone tissue engineering (BTE) and regenerative therapies. The review comprehensively discusses the implications of biological macromolecules, structure, and composition of polymeric scaffolds used in BTE. Various approaches to fabricating 3D BTE scaffolds are discussed, including solvent casting and particle leaching, freeze-drying, thermally induced phase separation, gas foaming, electrospinning, and sol–gel techniques. Rapid prototyping technologies such as stereolithography, fused deposition modeling, selective laser sintering, and 3D bioprinting are also covered. The immunomodulatory roles of polymeric scaffolds utilized for BTE applications are discussed. In addition, the features and challenges of 3D polymer scaffolds fabricated using advanced additive manufacturing technologies (rapid prototyping) are addressed and compared to conventional subtractive manufacturing techniques. Finally, the challenges of applying scaffold-based BTE treatments in practice are discussed in-depth.

ZnO-NPs loaded polyvinylidene fluoride (PVDF) composite nanofibers were fabricated by electrospinning and optimized using different concentrations (0, 2, and 5 wt %) of ZnO-NPs. Characterization techniques, for example, FTIR, SEM, XRD, and tensile strength analysis were performed to analyze the composite nanofibers. Molecular docking calculations were performed to evaluate the binding affinity of PVDF and ZnO@PVDF against the hexon protein of adenovirus (PDB ID: 6CGV). The cytotoxicity of tested materials was evaluated using MTT assay, and nontoxic doses subjected to antiviral evaluation against human adenovirus type-5 as a human respiratory model were analyzed using quantitative polymerase chain reaction assay. IC₅₀ values were obtained at concentrations of 0, 2, and 5% of ZnO-loaded PVDF; however, no cytotoxic effect was detected for the nanofibers. In 5% ZnO-loaded PVDF nanofibers, both the viral entry and its replication were inhibited in both the adsorption and virucidal antiviral mechanisms, making it a potent antiviral filter/mask. Therefore, ZnO-loaded PVDF nanofiber is a potentially prototyped filter embedded in a commercial face mask for use as an antiviral mask with a pronounced potential to reduce the spreading of infectious respiratory diseases, for example, COVID-19 and its analogues.

To examine the utilization of metal oxide nanoparticles (NPs) in different commercial products, this work focuses on the determination of cost-effective and scalable synthesis protocols. The solvothermal protocol is well-known as a scalable method but has recently been shown to lack economic feasibility. The mechanochemical method has recently been recognized to be a more economic and environmentally friendly substitute for the solvothermal method. In this study, zinc oxide nanoparticles (ZnO NPs) and copper oxide nanoparticles (CuO NPs) were synthesized using two (aqueous and organic) solvothermal (wet) methods and two (manual and automated) mechanochemical (dry) methods. The four methods were evaluated and compared. The automated mechanochemical method generated a significantly higher yield of ZnO NPs (82%) and CuO NPs (84%) using the least energy and time. However, the prepared ZnO NPs displayed higher cytotoxicity against Vero E6 cells when compared to that of CuO NPs. Because of their low cytotoxicity, CuO NPs synthesized via the automated mechanochemical method were selected for application onto cotton fabrics. Lower cytotoxicity was observed for CuO NPs treated fabrics with an IC50 of 562 mg/mL and ZnO treated fabrics with an IC50 at 23.93 mg/mL when the treated fabrics were tested against L929 fibroblast cells. Additionally, the cotton fabrics retained bactericidal and virucidal effects after four washes. Thus, the current study recommends the automated mechanochemical method as a cost-effective scalable approach for the synthesis of CuO NPs. The application of CuO NPs onto cotton fabrics generated washable antimicrobial face masks.

This study investigates the double role of N-doped carbon quantum dots (N-CQDs) in dye-sensitized solar cells (DSSCs) that operate under diffused- and low-light intensity conditions. We demonstrate that the incorporation of N-CQDs leads to a substantial improvement in the performance of DSSCs. Under standard one-sun illumination, the maximum power conversion efficiency (PCE) achieved with N-CQDs is 2% higher than that of the bare cell. Moreover, we introduce two new metrics, the diffused-light coefficient and the low-light intensity coefficient, to evaluate the performance of DSSCs under nonideal illumination conditions. The diffused-light coefficient is recorded at 1.55, which indicates a notable enhancement in diffused-light PCE with N-CQDs. In contrast, the low-light intensity coefficient shows a significant enhancement factor 2, which highlights the superior performance of N-CQD-based DSSCs under low-light conditions. Our findings demonstrate that N-CQDs play a dual role in DSSCs, by being added to both the commercial dye and the mesoporous TiO ₂ layer. These results provide valuable insights to develop and optimize DSSCs, especially for applications in indoor or low-light environments. The proposed metrics, the diffused light coefficient, and the low-light intensity coefficient, offer a meaningful assessment of the device's performance under nonideal illumination conditions.

Spinning of chitosan-poly (vinyl alcohol); Cs/PVA and chitosan- poly (caprolactone); Cs/PCL polymer blends were successfully achieved using electrospinning technique. The nanofiber mats of Cs/PVA and Cs/PCL were used as carriers for examining the release profile of Ciprofloxacin.HCl as broad-spectrum antibiotic. The shape, size, structure and composition of the nanofibers were characterized using FT-IR Spectroscopy and Scanning Electron Microscope (SEM). The release behavior was studied in Phosphate Buffer Solution (pH=7.4) using a UV-spectrophotometer. The antimicrobial activity of the produced nanofiber mats was studied using different strains of human pathogenic bacteria and Fungi. Compared to release profile from Cs/PVA/Ciprofloxacin.HCl nanofibers show faster drug release than that of Cs/PCL/Ciprofloxacin.HCl system,indicating that these nanofiber mats are promising active wound dressing materials for wound dressing applications.