Identification of proteins and bacteria based on a metal ion-gold nanocluster sensor array

We report a simple fluorescence sensor array based on metal ions-gold nanoclusters (AuNCs) for the identification of proteins and bacteria. In this study, three protein-stabilized AuNCs including BSA-AuNCs, HSA-AuNCs and Lys-AuNCs were firstly synthesized. After the purification of these protein@AuNCs by Zn and Cd respectively, six types of metal ion-protein@AuNCs were employed as the sensing elements to fabricate a fluorescence sensor array. In the presence of a protein, differential changes of fluorescence intensity on sensing elements generate a unique response pattern for the protein. In combination with linear discriminant analysis (LDA), 9 proteins with different concentrations were differentiated successfully. Moreover, 5 different bacteria were also identified by the proposed sensor array. The method is simple, rapid, and sensitive and shows potential for application in biomolecule sensing.