Chitosan functionalized gold nanostars as a theranostic platform for intracellular microRNA detection and photothermal therapy

The development of a theranostic platform that integrates both diagnostic and therapeutic capabilities is in great need for precise and personalized medicine. Here, we present a novel nanoplatform (AuNS@CS-hpDNA) formulated by chitosan functionalized gold nanostar composites and further complexed with fluorescent hairpin DNA (hpDNA) probes for tumor-related miRNA imaging and photothermal therapy (PTT). The optimized AuNS@CS-hpDNA nanoplatform mediated efficient hpDNA probe loading and intracellular delivery. Subsequently, the cytosol transfer of the hpDNA probe enabled specific hybridization using the targeted miRNA, which triggered the recovery of fluorescence for the precise detection of biomarker miR21 in living cells and realized the distinguishing cancer cell line MCF-7 and normal cells. Meanwhile, the AuNS@CS-hpDNA nanoplatform exhibited excellent photothermal conversion properties, which induced efficient cancer cell killing under laser irradiation. Thus, the developed AuNS@CS-hpDNA nanoplatform could simultaneously realize the precise detection of cancer cells and accurately initiate efficient PTT, which represents a promising strategy for precise cancer therapy.