Ionic exchange based intracellular self-assembly of pitaya-structured nanoparticles for tumor imaging

Abstract

The potential of metal nanoclusters in biomedical applications is limited due to aggregation-caused quenching (ACQ). In this study, an in situ self-assembled pitaya structure was proposed to obtain stable fluorescence emission through protein coronas-controlled distance between gold nanoclusters (Au NCs). Interestingly, the gold ion complexes coated with proteins of low isoelectric point (pI) nucleate at the secondary structure of proteins with high pI through ionic exchange within cells, generating fluorescent Au NCs. It is worth noting that due to the steric hindrance formed by the protein coronas on the surface of Au NCs, the distance between Au NCs can be controlled, avoiding electron transfer caused by close proximity of Au NCs and inhibiting fluorescence ACQ. This strategy can achieve fluorescence imaging of clinical tissue samples without observable side effects. Therefore, this study proposes a distance-controllable self-assembled pitaya structure to provide a new approach for Au NCs with stable fluorescence.