Synthesis of biocompatible silver nanoparticles by a modified polyol method for theranostic applications: Studies on red blood cells, internalization ability and antibacterial activity

Recently, there has been ongoing research in the field of nanotechnology and nanomedicine aiming at developing multifunctional biomaterials using noble metals. The unique properties of silver (Ag) are known from ancient times and thus are being explored for their behavior on the nano scale. Silver shows high antimicrobial activity against different microorganisms, while modification of the surface of its nanostructures can be useful in active targeting regarding cancer treatment. During the synthetic procedure, in order to obtain a more uniform sample of silver nanoparticles (Ag NPs) with spherical morphology, a stabilizer is essential. The stabilizers used not only control the progression of the reaction, but also increases the biocompatibility of the NPs. Thus, we managed to synthesize spherical and rod-like Ag NPs via a polyol method and stabilize them with polyvinylpyrrolidone (PVP). The resulted Ag NPs were characterized morphologically with Transmission Electron Microscopy (TEM) and further confirmed by their structural characterization (FT-IR, UV-Vis, Dynamic Light Scattering (DLS) and Zeta Potential). For their biocompatibility profile, we studied their interaction with red blood cells (RBCs) through hemolysis assay and we monitored their structural alterations through SEM. The antimicrobial activity was tested with the agar diffusion disc assay for Gram negative and Gram positive microorganisms E. coli and S. aureus respectively. Nanoparticles' (NPs) internalization and localization studies in cancer cells were monitored with fluorescence microscopy in MCF-7 and U87-MG. According to our results it is worth it to investigate the potential of these nanomaterials since they can have a significant role in applications of theranostics in nanomedicine.