A Spatially confined fluorescent nanogel with lock-type aptamer and AgInZnS quantum dots for stable cadmium ion...

Fluorescent nanogels are a novel type of biocompatible and responsive biomaterials that have attracted increasing attention due to the unique fluorescent properties derived from various fluorophores. In this study, a spatially confined fluorescent nanogel was developed through the co-encapsulation of AgInZnS quantum dots and a lock-type aptamer, enabling selective responsiveness to cadmium ions. The spatial confinement of both components within the nanogel enables rapid and sensitive detection of cadmium ions. It enhances biosensor stability under mildly alkaline environments (pH 6.5-8.0) and shows good detection stability in a 100-600 mmolL^-1 salt solution over a temperature range of 20-35 °C. This method achieves a low detection limit of 5.39 nmolL^-1 and a wide linear range spanning eight orders of magnitude (10 nmolL^-1 to 100 mmolL^-1). It also demonstrates good recovery (85.64 %-96.00 %) in real aquatic samples such as shrimp and crab. These spatially confined nanogels show great promise for broad applications in analytical sensing and biomedical fields.