Sterically stabilized fluorescent silver nanoconjugates for optical discrimination of Cu(ii) in real samples and in vitro bioimaging of the Cu(ii) scavenging process in human lymphocytes by atomic force microscopy

Abstract

Highly fluorescent sterically stabilized silver nanoparticles (Cf-AgNPs) have been prepared by a facile thermochemical method in a single step and with excellent long-term stability. The method involves reduction of silver nitrate to Ag via carbonyl groups of the β-lactam ring and the amide of cefaclor. The materials have been characterized by fluorescence and absorption spectroscopy, atomic force microscopy, FT-IR spectroscopy, ¹H NMR and MALDI-TOF-MS. The luminescence arises from small metal clusters (i.e., Ag₂, Ag₃ and Ag₄), which is efficiently quenched by the paramagnetic quencher Cu(II). The Cf-AgNPs allowed us to detect Cu(II) in the range of 0.8 to 3.3 µM with a detection limit of 0.282 µM. Moreover, Cu(II) was selectively recognized in human blood plasma by Cf-AgNPs. We have also evaluated the cytotoxicity of Cf-AgNPs and explored their scavenging potential against Cu(II) in B and T lymphocytes with the help of AFM.