Synthesis of 4-formyl pyridinium propylthioacetate stabilized silver nanoparticles and their application in chemosensing of 6-aminopenicillanic acid (APA)

Widespread use of antibiotics for humans and animals health has led to drugs entering the environment, such as lakes and streams worldwide. It is imperative to develop methods to screen these in drinking water supplies. We developed a novel nanoparticles-based probe to detect the β-lactam skeleton 6-APA. Cationic ligand thiopyridine stabilized silver nanoparticles (ThPy-AgNPs) were synthesized and used for chemosensing of the drug 6-aminopenicillanic acid (6-APA). Along with several drugs, during UV–visible titration with ThPy-AgNPs, a distinctive decrease in surface plasmon resonance bands absorbance was observed with 6-APA. The ThPy-AgNPs-based detection system for 6-APA is based on the phenomenon of de-aggregation and is monitored by using UV–visible spectrophotometry and atomic force microscopy measurements. The process is relatively rapid, highly specific and selective for 6-APA when tested against several other drugs. This optical method can recognize 6-APA as low as 1 μM concentration, and drug detection is independent of the pH of media. Moreover, the optimized sensing protocol is able to sense 6-APA in human blood plasma samples and is not altered by presence of other interfering drugs. It is anticipated that this method will be of immense value to detect 6-APA for blood samples and drinking water.