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

Abstract

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 afford long-term tracking of miRNAs (5 days) in the differentiating hMSCs without the need of continuously replenishing cell culture medium with fresh nanoprobes. Our results demonstrate the capability of our Au@PDA-hpDNA nanoprobes for monitoring the differentiation status of hMSCs (i.e., differentiating versus undifferentiated) via the detection of specific miRNAs in living stem cells. Our nanoprobes show great promise in the investigation of the long-term dynamics of stem cell differentiation, identification and isolation of specific cell types, and high-throughput drug screening.

Iron oxide nanozyme catalyzed synthesis of fluorescent polydopamine for light-up Zn2+detection

“…4 Recently, polydopamine was found to be fluorescent under certain conditions. For example, Zhang and co-workers obtained fluorescent polydopamine (FPD) nanoparticles (NPs) by treating polydopamine with concentrated H2O2.…”

Recent advances in high-performance fluorescent and bioluminescent RNA imaging probes

“…Choi et al showed that polydopamine (PDA) coated GNPs have much better stability in cells and can track miR-29b and miR-31 (involved in differentiation progress of human mesenchymal stem cells) simultaneously for five days 122 . In detail, they coated polydopamine (PDA) on GNPs and further adsorbed β-hairpin DNA through π-π interactions.…”

“…In detail, they coated polydopamine (PDA) on GNPs and further adsorbed β-hairpin DNA through π-π interactions. In the absence of target miRNAs, the fluorescence of β-hairpin DNA was totally quenched by both GNPs and PDA, but in the presence of target miRNAs, the β-hairpin DNA detached from the PDA surface and bound with target miRNAs, restoring fluorescence 122 .…”

A Two‐Stage Dissociation System for Multilayer Imaging of Cancer Biomarker‐Synergic Networks in Single Cells

“…First, we prepared bare AuNPs (60 nm) by ac onventional seed-growing method. Tw op robes were synthesized for different targeting purposes.I nS cheme 1b,C y5-labeled consensussite double-stranded DNA(ds-DNA, with aspecial sequence to target the central domain of the p53 protein) was immobilized onto the PDAshell through p-p interactions, [10] forming Probe 1. [8] Next, DAPB molecules were conjugated on the PDAshell by reversible bonding between the catechol groups of PDA and boronic acids.…”