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

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 (H2O2). As for the stepwise enlargement for gold nanoclusters with increasing concentration of H2O2, the RLS intensity can be gradually increased, which offers the new approach for the quantitative detection of H2O2. Combined with the biocatalytic reaction that produces H2O2 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 H2O2 by using their corresponding oxidases.