Plant-mediated green synthesis of metal-based nanoparticles for dermopharmaceutical and cosmetic applications

Silver has been used since time immemorial in different chemical form to treat burns, wounds and several infections caused by pathogenic bacteria. Advancement of biological process of nanoparticles synthesis is evolving into a key area of nanotechnology. The current study deals with the synthesis, characterization of silver nanoparticles using Iresine herbstii and evaluation of their antibacterial, antioxidant and cytotoxic activity. The reaction mixture turned to brownish gray color after 7 days of incubation and exhibits an absorbance peak around 460 nm characteristic of Ag nanoparticle. Scanning electron microscopy (SEM) and EDX analysis showed silver nanoparticles were pure and polydispersed and the size were ranging from 44 to 64 nm. X-ray diffraction (XRD) studies revealed that most of the nanoparticles were cubic and face centered cubic in shape. Fourier transform infrared spectroscopy (FTIR) showed nanoparticles were capped with plant compounds. Biosynthesized silver nanoparticles showed potent antibacterial activity against human pathogenic bacteria. Phytosynthesized nanoparticles exhibited strong antioxidant activity as well as cytotoxicity against HeLa cervical cell lines. The approach of green synthesis seems to be cost efficient, eco-friendly and easy alternative to conventional methods of silver nanoparticles synthesis. The powerful bioactivity demonstrated by the synthesized silver nanoparticles leads towards the clinical use as antibacterial, antioxidant as well as cytotoxic agent.

In this report, we have designed a simple and efficient green chemistry approach for the synthesis of colloidal silver nanoparticles (b-AgNPs) that is formed by the reduction of silver nitrate (AgNO3) solution using Olax scandens leaf extract. The colloidal b-AgNPs, characterized by various physico-chemical techniques exhibit multifunctional biological activities (4-in-1 system). Firstly, bio-synthesized silver nanoparticles (b-AgNPs) shows enhanced antibacterial activity compared to chemically synthesize silver nanoparticles (c-AgNPs). Secondly, b-AgNPs show anti-cancer activities to different cancer cells (A549: human lung cancer cell lines, B16: mouse melanoma cell line & MCF7: human breast cancer cells) (anti-cancer). Thirdly, these nanoparticles are biocompatible to rat cardiomyoblast normal cell line (H9C2), human umbilical vein endothelial cells (HUVEC) and Chinese hamster ovary cells (CHO) which indicates the future application of b-AgNPs as drug delivery vehicle. Finally, the bio-synthesized AgNPs show bright red fluorescence inside the cells that could be utilized to detect the localization of drug molecules inside the cancer cells (a diagnostic approach). All results together demonstrate the multifunctional biological activities of bio-synthesized AgNPs (4-in-1 system) that could be applied as (i) anti-bacterial & (ii) anti-cancer agent, (iii) drug delivery vehicle, and (iv) imaging facilitator. To the best of our knowledge, there is not a single report of biosynthesized AgNPs that demonstrates the versatile applications (4-in-1 system) towards various biomedical applications. Additionally, a plausible mechanistic approach has been explored for the synthesis of b-AgNPs and its anti-bacterial as well as anti-cancer activity. We strongly believe that bio-synthesized AgNPs will open a new direction towards various biomedical applications in near future.