Arsenic ion assisted core–satellites nano-assembly of gold nanoparticles for its colorimetric determination in water

Arsenic contamination in water has threatened lives globally. The capability of arsenic to interact with the sulfhydryl group of amino acids in human body is considered as one of the factors leading to its increased toxicity and there is the dire need for development of better detection platforms. In this study, advantage of natural biomimetic interaction between thiol rich ligands and arsenic ions along with the effect of nanoarchitecture was evaluated by fabricating a heterostructural bioreceptor probe which interacts with arsenic based on affinity interaction to bring about a visual colorimetric response via plasmon coupling. As (III) ions can bind to these selective ligands and self-assemble to form gold nanoparticle networks. The mesh-like nanoarchitecture enhances the available surface area for interaction between selective bioreceptor heads and As (III) ions. The developed chemoprobe was validated by assessing the spiked real water samples with recoveries of 95–103%. The results indicate that the chemical nanoprobe was responsive over a wide linear range of 1 to 200 μg L⁻¹, offering the detection limit of 0.22 μg L⁻¹ and selective for As (III) ions in a presence of 10 times more concentrated solution of the competing ions which indicates at the potential of nano-architecture in improving current detection systems.