Gold Nanorod-Based Chrono-Colorimetric Sensor Arrays:A Promising Platform for Chemical Discrimination Applications

摘要

Most array-based sensing platforms, to date, utilize static response patterns for discrimination of a wide variety of analytes, but only a few studies have focused on the important task of quantitatively resolving structural isomers, which are nowadays important because of their broad usage in medicines and industries. A possible way of accomplishing this feat is to combine kinetic (rather than static) sensor response profiles with the chemical tongue strategy to allow the development of array-based sensors for isomeric discrimination. Here, by adding the time dimension, a simple and novel gold nanorod (AuNR)-based chrono-colorimetric sensor array is proposed for chemical discrimination applications. Because of their similar structure but different redox potentials, dihydroxybenzene (DHB) structural isomers have been chosen, as models, to evaluate the applicability of the proposed array. The principle of the array relies on various growth rates of silver shells on AuNRs at different silver ion/AuNR concentration ratios owing to the different kinetic behaviors of DHBs, which canbe used as fingerprints to identify DHBs with the help of multivariateanalysis methods. The combinatorial colorimetric response of AuNRsupon DHB addition has been analyzed by linear discriminant analysisand hierarchical cluster analysis. Finally, identification of individualDHBs or their mixtures in real samples confirms the potential applicationof the proposed array.