In the primitive era, humans benefited partially from plants and metals to treat microbial infections. Later these infections were cured with antibiotics but further suffered from resistance issues. In searching of an alternative, researchers developed an adjuvant therapy but were hampered by spreading resistance. Subsequently, nanoparticles (NPs) were proposed to cease the multi-drug resistant bacteria but were hindered due to toxicity issues. Recently, a novel adjuvant therapy employed metals and botanicals into innovative nanotechnology as nano-antibiotics. The combination of green synthesized metallic NPs with antibiotics seems to be a viable platform to combat against MDR bacteria by alleviating resistance and toxicity. This review focuses on the primitive to present era dealings with bacterial resistance mechanisms, newer innovations of nanotechnology and their multiple mechanisms to combat resistance. In addition, special focus is paid on greener NPs as antibiotic carriers, and their future prospects of controlled release and toxicity study.

The aim of the work is to synthesize iron oxide (α-Fe2O3) nanoparticles using Sida cordifolia plant extract along with evaluation of its antibacterial activity. The presence of phytochemicals in Sida cordifolia methanolic plant extract was investigated by HPTLC and LC-MS/TOF. The probable mechanism for formation of α-Fe2O3 nanoparticles in mediation with plant extract was demonstrated. The green synthesized iron oxide nanoparticles (α-Fe2O3 NPs) were characterized by using X-ray diffraction, scanning, and transmission electronic microscopy, TG-DTA, FTIR, and UV spectroscopy. The crystallite size of prepared α-Fe2O3 nanoparticles estimated via Debye-Scherrer formula and Williamson-Hall plot was around 20 nm which is in accordance with particle size in TEM images. The S. cordifolia mediated iron-oxide nanoparticles (α-Fe2O3 NPs) hold potent antibacterial activity against various gram positive and gram negative bacteria.