A multicoloured Au NCs based cross-reactive sensor array for discrimination of multiple proteins.

Early diagnosis of cancer is a critical element in patient prognosis and establishing effective therapy regimens. Here, we developed an easily accessible and potentially powerful effective cross-reactive sensor array based on six kinds of fluorescent Au NCs for discriminating multiple proteins according to the diverse fluorescence intensity response patterns. The identification of proteins at nanomolar concentrations with excellent reproducibility and high sensitivity could be achieved by linear discrimination analysis (LDA) of the response patterns. In addition, hydrogen bonding and van der Waals forces mainly dominated the interaction between Au NCs and proteins as illustrated by the isothermal titration calorimetry (ITC) experiment. Notably, multiple proteins could still be well discriminated in the presence of a human urine sample. Furthermore, serum samples from breast cancer patients, rectal cancer patients and healthy people could be effectively discriminated, demonstrating great potential for applications in biomedical diagnostics.