DNA-coated gold nanoparticles for tracking of hepatocyte growth factor secreted by transplanted mesenchymal stem cells in pulmonary fibrosis therapy

Identification of paracrine factors secreted by transplanted mesenchymal stem cells (MSCs) during the treatment of idiopathic pulmonary fibrosis (IPF) is essential for understanding the role of MSCs in the therapy. Herein, we report a facile and efficicent strategy for in vivo tracking the secretion of hepatocyte growth factor (HGF) in MSCs during IPF therapy. In our strategy, a novel nanoflare tracer consisting of gold nanoparticles (AuNPs), complementary sequences and dye-labeled recognition sequences is developed. Briefly, the AuNPs are functionalized with oligonucleotide complementary sequences hybridized to the organic dye-labeled recognition sequences, where the organic fluorophores are in close proximity to the AuNPs. In the absence of targets, the dye and AuNPs are spearated from each other, inducing the quenching of fluorescence signal. However, in the presence of targets, the recognition sequences gradually fall off from the AuNPs, causing the fluorescence signal rising. In brief, in vivo monitoring of the dynamic expression of HGF mRNA in transplanted MSCs during IPF therapy in the current work may provide new insight into the paracrine process of the transplanted MSCs, thereby advancing the MSC-based IPF therapy toward clinical applications.