Facile preparation of fluorescent gold nanocluster via polysaccharide-templated approach and its application for Cu2+ sensing

•CS was used as a protective layer for preparing flurescent gold nanoclusters via template-based strategy.•CS-directed AuNCs could detect Cu2+ selectively and sensitively via non-covalent d10-d10 metallophilic interaction.•The detection limit of CS-AuNCs was 8nM.•The satisfactory results were obtained for determination of Cu2+ using CS-AuNCs probe in real samples.