Abstract
Due to the indiscriminate usage of organophosphates in military and agriculture, there is an increasing demand to develop sensors for monitoring organophosphorus nerve agents and pesticides. Herein, a sensitive two-dimensional photonic crystal (2D-PC) biosensor as a part of a portable device for the detection of Dipterex is presented. The 2D-PC array was self-organized on the water-air interface using 600 nm polystyrene (PS) colloidal particles, and it was further embedded into a polyacrylamide-acrylic acid (PAM-AA) hydrogel. After condensation between the amine groups of acetylcholinesterase (AChE) and the carboxyl groups of the hydrogel, a novel sensing platform of 2D-PC hydrogel with AChE as the recognition agent was constructed. The lattice spacing of AChE-functionalized 2D-PC was inversely proportional to the logarithm of the Dipterex concentration from 10(-14) mol L(-1) to 10(-4) mol L(-1) with estimated limit of detection (LOD) of 7.7 × 10(-15) mol L(-1). Simultaneously, the structural color of AChE-functionalized 2D-PC varied from yellow to blue. The biosensor achieved "naked-eye" detection due to which the use of AChE-functionalized 2D-PC is a promising technique for onsite and fast screening of organophosphates.