A novel resonance light scattering sensing for glucose based on the conversion of gold nanoclusters into gold nanoparticles

摘要

A novel and label-free resonance light scattering (RLS) assay for sensing glucose was constructed based on the conversion of gold nanoclusters into gold nanoparticles. It was observed that a size-focusing conversion of ultra-small size protein stabilized gold nanoclusters (Au NCs) into larger diameter gold nanoparticles (Au NPs) after the introduction of hydrogen peroxide (H_2O_2). As for the stepwise enlargement for gold nanoclusters with increasing concentration of H_2O_2, the RLS intensity can be gradually increased, which offers the new approach for the quantitative detection of H_2O_2. Combined with the biocatalytic reaction that produces H_2O_2 by glucose oxidase, the strategy of biocatalytic-induced size conversion provides a new way for sensing glucose by RLS technique. The method exhibits good performance with high selectivity, a low detection limit (20 nM) and excellent stability both in the buffer and serum samples. The assay shows great potential for versatile application of detecting various substrates which generate H_2O_2 by using their corresponding oxidases.