Polyaniline-Coated Surface-Modified Ag/PANI Nanostructures for Antibacterial and Colorimetric Melamine Sensing in Milk Samples

[Image: see text] Silver nanoparticles (Ag NPs) are trusted candidates for many biological characteristics and applications due to their low toxicity and biologically benign nature. Due to inherited bactericidal characteristics, these Ag NPs are surface-modified with polyaniline (PANI), an organic polymer that has distinctive functional groups which have their role in inducing ligand properties. The Ag/PANI nanostructures were synthesized by the solution method, and their antibacterial and sensor properties were evaluated. Maximum inhibitory performance was seen with modified Ag NPs compared with their pure counterparts. The Ag/PANI nanostructures (0.1 μg) were incubated with E. coli bacteria, and almost complete inhibition was seen after 6 h. Furthermore, the colorimetric melamine detection assay by Ag/PANI as a biosensor also yielded efficient and reproducible results up to a 0.1 μM melamine concentration in daily-life milk samples. The chromogenic shift in color along with spectral validation through UV–vis spectroscopy and FTIR spectroscopy proves the credibility of this sensing method. Thus, high reproducibility and efficiency make these Ag/PANI nanostructures practical candidates for food engineering and biological properties.