A Gold@Polydopamine Core–Shell Nanoprobe for Long-Term Intracellular Detection of MicroRNAs in Differentiating Stem Cells

作者：Chun Kit K. Choi, Chun Kit K. Choi, Jinming Li, Kongchang Wei, Yang J. Xu, Lok Wai Cola Ho, Meiling Zhu, Kenneth K.W. To, Chung Hang J. Choi, Chung Hang Jonathan Choi, Liming Bian · 发表于：Journal of the American Chemical Society · 年份：2015 · DOI：10.1021/jacs.5b01457 · 被引用次数：221 · 研究领域：Advanced biosensing and bioanalysis techniques、RNA Interference and Gene Delivery、MicroRNA in disease regulation

The capability of monitoring the differentiation process in living stem cells is crucial to the understanding of stem cell biology and the practical application of stem-cell-based therapies, yet conventional methods for the analysis of biomarkers related to differentiation require a large number of cells as well as cell lysis. Such requirements lead to the unavoidable loss of cell sources and preclude real-time monitoring of cellular events. In this work, we report the detection of microRNAs (miRNAs) in living human mesenchymal stem cells (hMSCs) by using polydopamine-coated gold nanoparticles (Au@PDA NPs). The PDA shell facilitates the immobilization of fluorescently labeled hairpin DNA strands (hpDNAs) that can recognize specific miRNA targets. The gold core and PDA shell quench the fluorescence of the immobilized hpDNAs, and subsequent binding of the hpDNAs to the target miRNAs leads to their dissociation from Au@PDA NPs and the recovery of fluorescence signals. Remarkably, these Au@PDA-hpDNA nanoprobes can naturally enter stem cells, which are known for their poor transfection efficiency, without the aid of transfection agents. Upon cellular uptake of these nanoprobes, we observe intense and time-dependent fluorescence responses from two important osteogenic marker miRNAs, namely, miR-29b and miR-31, only in hMSCs undergoing osteogenic differentiation and living primary osteoblasts but not in undifferentiated hMSCs and 3T3 fibroblasts. Strikingly, our nanoprobes can affor...