The vast domain of regenerative medicine comprises complex interactions between specific cells’ extracellular matrix (ECM) towards intracellular matrix formation, its secretion, and modulation of tissue as a whole. In this domain, engineering scaffold utilizing biomaterials along with cells towards formation of living tissues is of immense importance especially for bridging the existing gap of late; nanostructures are offering promising capability of mechano-biological response needed for tissue regeneration. Materials are selected for scaffold fabrication by considering both the mechanical integrity and bioactivity cues they offer. Herein, polycaprolactone (PCL) (biodegradable polyester) and ‘nature’s wonder’ biopolymer silk fibroin (SF) are explored in judicious combinations of emulsion electrospinning rather than conventional electrospinning of polymer blends. The water in oil (W/O) emulsions’ stability is found to be dependent upon the concentration of SF (aqueous phase) dispersed in the PCL solution (organic continuous phase). The spinnability of the emulsions is more dependent upon the viscosity of the solution, dominated by the molecular weight of PCL and its concentration than the conductivity. The nanofibers exhibited distinct core-shell structure with better cytocompatibility and cellular growth with the incorporation of the silk fibroin biopolymer.

Three Zn-based alloys (Zn1Cu, Zn2Cu, and Zn3Cu) were developed by the addition of Cu (1, 2, and 3 wt %) into commercially pure Zn. This report systematically investigates the potential for these newly developed Zn-based alloys as biodegradable materials. Microstructural studies reveal the presence of spherical-shaped nanosized precipitates of ε-CuZn 4 in the Zn1Cu alloy, whereas Zn2Cu and Zn3Cu alloys exhibit the presence of both micron-and nanosized precipitates of ε-CuZn 4 . The mechanical properties such as hardness, tensile and compressive strengths improve significantly with an increase in the amount of Cu in the alloy. The Zn3Cu alloy exhibits the highest yield strength (225 ± 9 MPa) and ultimate tensile strength (330 ± 12 MPa) among all of the alloys, which are ∼2.7 and 2 times higher than those of pure Zn. In vitro degradation behavior is evaluated by the potentiodynamic polarization study and immersion testing in Hank's solution for 20 and 75 days. The corrosion rate after both polarization and immersion testing follows the order of pure Zn < Zn1Cu < Zn3Cu < Zn2Cu. An electrochemical impedance spectroscopy (EIS) study also concludes that Zn2Cu shows the lowest corrosion resistance. The % cell viability values of 3T3 fibroblasts cells after 5 days of culture in a 50% diluted extract of pure Zn, Zn2Cu, and Zn3Cu alloys are 76 ± 0.024, 86.18 ± 0.033, and 92.9 ± 0.026%, respectively, establishing the improved cytocompatibility of the alloys as compared to pure Zn. Furthermore, an antibacterial study also reveals that the Zn3Cu alloy exhibits 80, 67, and 100% increases in the zone of inhibition (ZOI) for Escherichia coli, Bacillus subtilis, and Pseudomonas aeruginosa bacteria, respectively, as compared to that of pure Zn.

Metal/metal oxide nanoparticles have long been used as an antibacterial substitute, but fabrication of an effective carrier or delivery matrix for achieving a sustain release profile with high bactericidal efficacy alongwith good cytocompatibility is still an unresolved challenge. Herein, the study demonstrates a facile and unique route to fabricate a hierarchical nanobiocomposite with effective loading of ZnO/silver nanoparticles (Ag–NPs) in order to attain excellent bactericidal efficacy with good and sustainable release profile. Surface functionalized eggshell membranes (ESM) were deployed as three-dimensional loading matrices for efficient loading of ZnO/Ag–NPs. A simple sonochemical guided approach was adopted to synthesize ZnO nanoflakes in situ onto the microfibrous ESM and decorate it with Ag–NPs to fabricate a nanobiocomposite. Microstructural analysis confirms successful anchorage of ZnO nanoflakes and Ag–NPs on microfibrous eggshell membrane thus reinstating hierarchical morphology of the nanobiocomposites. FT-IR spectra confirms the biochemical composition whereas XPS analysis ratifies the interaction between ZnO and Ag–NPs further substantiating metallic state of Ag. ICP-MS studies affirms excellent and sustainable release profile of nanoparticles from the nanobiocomposites. Owing to the synergistic activity of ZnO/Ag–NPs, the nanobiocomposites demonstrated exceptional bactericidal activity against Gram-negative, E. coli or P. aeruginosa, and Gram-positive, S. aureus or B. subtilis, bacterial cells. Moreover, inherent antibacterial property of microfibrous natural ESM contributes positively toward the overall bactericidal activity. Further, a direct exposure of nanobiocomposites with NIH 3T3 cells revealed the biocompatible nature of developed matrices. Prolonged exposure also indicated that the 3T3 cells tend to adhere onto the microfibrous nanobiocomposite without any observable deformation in cellular morphology. The architectural tribology and excellent bactericidal performance of the nanobiocomposites along with its cytocompatible nature manifests its application as an alternate platform for varying biomedical applications.

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Several disease conditions, such as cancer metastasis and atherosclerosis, are deeply connected with the complex biophysical phenomena taking place in the complicated architecture of the tiny blood vessels in human circulatory systems. Traditionally, these diseases have been probed by devising various animal models, which are otherwise constrained by ethical considerations as well as limited predictive capabilities. Development of an engineered network-on-a-chip, which replicates not only the functional aspects of the blood-carrying microvessels of human bodies, but also its geometrical complexity and hierarchical microstructure, is therefore central to the evaluation of organ-assist devices and disease models for therapeutic assessment. Overcoming the constraints of reported resource-intensive fabrication techniques, here, we report a facile, simple yet niche combination of surface engineering and microfabrication strategy to devise a highly ordered hierarchical microtubular network embedded within a polydimethylsiloxane (PDMS) slab for dynamic cell culture on a chip, with a vision of addressing the exclusive aspects of the vascular transport processes under medically relevant paradigms. The design consists of hierarchical complexity ranging from capillaries (∼80 μm) to large arteries (∼390 μm) and a simultaneous tuning of the interfacial material chemistry. The fluid flow behavior is characterized numerically within the hierarchical network, and a confluent endothelial layer is realized on the inner wall of microfluidic device. We further explore the efficacy of the device as a vascular deposition assay of circulatory tumor cells (MG-63 osteosarcoma cells) present in whole blood. The proposed paradigm of mimicking an in vitro vascular network in a low-cost paradigm holds further potential for probing cellular dynamics as well as offering critical insights into various vascular transport processes.