Progressive aging harms bone tissue structure and function and, thus, requires effective therapies focusing on permanent tissue regeneration rather than partial cure, beginning with regenerative medicine. Due to advances in tissue engineering, stimulating osteogenesis with biomimetic nanoparticles to create a regenerative niche has gained attention for its efficacy and cost-effectiveness. In particular, hydroxyapatite (HAP, Ca₁₀(PO₄)₆(OH)₂) has gained significant interest in orthopedic applications as a major inorganic mineral of native bone. Recently, magnetic nanoparticles (MNPs) have also been noted for their multifunctional potential for hyperthermia, MRI contrast agents, drug delivery, and mechanosensitive receptor manipulation to induce cell differentiation, etc. Thus, the present study synthesizes HAP-decorated MNPs (MHAP NPs) via the wet chemical co-precipitation method. Synthesized MHAP NPs were evaluated against the preosteoblast MC3T3-E1 cells towards concentration-dependent cytotoxicity, proliferation, morphology staining, ROS generation, and osteogenic differentiation. The result evidenced that MHAP NPs concentration up to 10 µg/mL was non-toxic even with the time-dependent proliferation studies. As nanoparticle concentration increased, FACS apoptosis assay and ROS data showed a significant rise in apoptosis and ROS generation. The MC3T3-E1 cells cocultured with 5 µg/mL MHAP NPs showed significant osteogenic differentiation potential. Thus, MHAP NPs synthesized with simple wet chemistry could be employed in bone regenerative therapy.

Energy harvesting technologies have found significant importance over the past decades due to the increasing demand of energy and self-powered design of electronic and implantable devices. Herein, we demonstrate the design and application of in situ poled highly flexible piezoelectric poly vinylidene fluoride (PVDF) graphene oxide (GO) hybrid nanofibers in aligned mode for multifaceted applications from locomotion sensors to self-powered motion monitoring. Here we exploited the simplest and most versatile method, called electrospinning, to fabricate the in situ poled nanofibers by transforming non-polar α-phase of PVDF to polar β- phase structures for enhanced piezoelectricity under high bias voltage. The flexible piezoelectric device fabricated using the aligned mode generates an improved output voltage of 2.1 V at a uniform force of 12 N. The effective piezoelectric transduction exhibited by the proposed system was tested for its multiple efficacies as a locomotion detector, bio-e-skin, smart chairs and so on.

Here, we report the polycaprolactone (PCL) based 2D nanofibrous scaffold with minimal loading (0.0005–0.002 wt%) of Au-reinforced graphene (RG) sheets for improved bone tissue regeneration. The microsized graphene oxide (GO) sheets (829 nm) were tailored strategically to 282 nm-sized monodispersed nanosheets for uniform electrostatic attachment of gold nanoparticles (GNPs). The GNPs-GO sheets were reduced to GNPs-RG sheets using a visible-light-induced chemical-free green method where the oxygen functional groups of GO have not been removed completely to enhance the functionality of GNPs-RG for bone tissue regeneration. The monodispersibility of GNPs-RG sheets helped to prepare PCL-based nanofibrous scaffolds with uniformly distributed GNPs-RG (0.002 wt%) with higher electrical conductivity (>3.5 times) and greater mechanical strength (>4.5 times). The electrostatic field simulation studies with COMSOL suggested that there was a uniform distribution of the electric field. The GNPs-RG addition creates an apt adhesion site due to their multifunctional and conductive properties for PCL@GNPs-RG nanofibrous scaffold which resulted in enhanced cell adhesion and proliferation of MC3T3-E1 cells. The PCL@GNPs-RG nanofibrous scaffold showed higher alkaline phosphatase activity and improved calcium mineralization after 21 d of incubation. The results indicated that the PCL@GNPs-RG scaffold has a promising capacity and potential for bone tissue regeneration.