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Many types of polymer nanofibers have been introduced as artificial extracellular matrices. Their controllable properties, such as wettability, surface charge, transparency, elasticity, porosity and surface to volume proportion, have attracted much attention. Moreover, functionalizing polymers with other bioactive components could enable the engineering of microenvironments to host cells for regenerative medical applications. In the current brief review, we focus on the most recently cited electrospun nanofibrous polymeric scaffolds and divide them into five main categories: natural polymer-natural polymer composite, natural polymer-synthetic polymer composite, synthetic polymer-synthetic polymer composite, crosslinked polymers and reinforced polymers with inorganic materials. Then, we focus on their physiochemical, biological and mechanical features and discussed the capability and efficiency of the nanofibrous scaffolds to function as the extracellular matrix to support cellular function.

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In this study, toxicity of biologically synthesized silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) was compared using zebrafish as a model organism. At 96 h, LC 50 of AgNPs and AuNPs was found to be 24.5 µg/L and 41 mg/L, respectively. Following the LC 50 determination, half of the LC 50 of AgNPs (12.25 µg/L) and AuNPs (20.5 mg/L) was exposed to adult zebrafishes for 14 days. Morphological changes, liver marker enzymes, reactive oxygen species (ROS) generation, genotoxic effects and mRNA expression levels of oxidative stress and innate immune response related genes were studied using nanoparticle treated gill, liver and blood cells. In this study, AgNP-treated gill and liver tissues showed a number of morphological changes such as cell membrane damage, irregular cell outlines, pyknotic nuclei and complete disruption of gill and liver cells; on the contrary, AuNPs treated liver tissues alone showed such changes. The levels of liver marker enzymes such as alanine aminotransferase and aspartate aminotransferase were increased after AgNPs treatment when compared to AuNPs treatment. AgNP-treated liver cells showed higher levels of ROS generation than the control; on the other hand, AuNPs treatment exhibited lower levels of ROS generation than the control. Interestingly, AgNP-treated blood cells showed micronuclei formation and nuclear abnormalities, while AuNPs treatment did not show such effects. Based on these observations, it is clear that AgNPs may cause oxidative stress and immunotoxicity to adult zebrafish than the AuNPs. However, these results clearly reveal the significance of relatively safe and less toxic bionanomaterials for possible biomedical applications.

Silver nanoparticles (AgNPs) have been known for their inhibitory and bactericidal effects. In the present study, less toxic AgNPs using is reported for the first time. The obtained AgNPs were characterized using UV-Visible spectrophotometer, XRD, FT-IR, FE-SEM with EDAX and HR-TEM. AgNPs showed the maximum absorbance at 420-430 nm. The transmission electron micrograph revealed the formation of considerably uniform-sized AgNPs with an average size of 20-50 nm. The reducing and capping agents responsible for AgNP synthesis were identified by FT-IR. AgNP-incorporated cotton fabrics exhibited promising antibacterial activity against pathogenic bacteria. In addition, the in vitro cell viability of Vero cells (African green monkey kidney cells) was analyzed and the IC value of AgNPs was found to be 62.8 µg/mL. Taken together, these results clearly reveal less toxic AgNPs which could be exploited for various biomedical applications.