DNA-Stabilized Silver Nanoclusters for Label-Free Fluorescence Imaging of Cell Surface Glycans and Fluorescence Guided Photothermal Therapy

A multifunctional nanoplatform that enables the integration of biological detection, imaging diagnosis, and synergistic therapy into a single nanostructure holds great promise for nanoscience and nanomedicine. Herein, a novel theranostic platform was presented for label-free imaging of cell surface glycans based on DNA/silver nanoclusters (AgNCs) via hybridization chain reaction (HCR) and fluorescence guided photothermal therapy (PTT). In this strategy, a dibenzocyclooctyne (DBCO)-functionalized DNA and two hairpin structures of DNA/AgNCs probes were involved. Following metabolic glycan labeling, the binding of DBCO-functionalized DNA to cell surface initiated HCR, and then cell surface glycans were specifically labeled by DNA/AgNCs fluorescent probes. Furthermore, this signal amplification strategy was adopted in quantitative analysis, and the detection limit could be achieved as low as 20 cells in 200 mu L of binding buffer. Moreover, the remarkable photothermal properties of DNA/AgNCs via HCR led to efficient killing of cancer cells and inhibited the tumor growth under imaging guide. In this strategy, DNA/AgNCs were utilized to detect the cellular glycans, which aided in overcoming the high cost and instability of fluorescent dyes. Simultaneously, the HCR process avoided the introduction of excessive azido-sugars under the precondition of ensuring apparent fluorescence. These results indicated that the developed nanoplatform has great potential for specific cell surface glycans imaging and fluorescence guided PTT.