An electrochemiluminescence biosensor based on target-responsive DNA hydrogel for T-2 toxin

In this work, an electrochemiluminescence (ECL) biosensor for T-2 toxin detection has been designed by combining the high specificity of a DNA hydrogel system with the convenience and sensitivity of homogeneous ECL detection. Specifically, A hydrogel was engineered through the reaction between the carboxyl group of hyaluronic acid (HA) and the amino groups of both polyethyleneimine (PEI) and DNA-modified strands, resulting in a three-dimensional network that encapsulates glucose oxidase. Glucose oxidase (GOD) is capable of catalyzing the conversion of glucose into hydrogen peroxide (H₂O₂), which is a co-reactant necessary for the chemiluminescent reagent luminol to emit light. Upon the presence of the target analyte T-2 toxin, the aptamer recognizes and binds to it, leading to the dissociation and cleavage of the hydrogel framework. This process results in the leakage of the encapsulated GOD into the supernatant. Subsequently, Adding the collected supernatant to a phosphate-buffered saline (PBS) solution containing glucose and luminol for ECL testing yields a noticeable signal change. This sensor eliminates the need for electrode modification, simplifying the operation. Within a concentration range of 10 fg/mL to 100 ng/mL, the ECL signal intensity exhibits an excellent linear relationship with the logarithm of the target concentration, with a detection limit as low as 0.32 fg/mL. The method also demonstrates excellent reproducibility and stability. The sensor demonstrated precise detection capabilities in actual milk and beer samples, a crucial aspect for research focused on specific targets.