Intracellular
MicroRNA Imaging and Specific Discrimination
of Prostate Cancer Circulating Tumor Cells Using Multifunctional Gold
Nanoprobe-Based Thermophoretic Assay
Circulating tumor cells (CTCs) have emerged as powerful
biomarkers
for diagnosis of prostate cancer. However, the effective identification
and concurrently accurate imaging of CTCs for early screening of prostate
cancer have been rarely explored. Herein, we reported a multifunctional
gold nanoprobe-based thermophoretic assay for simultaneous specific
distinguishing of prostate cancer CTCs and sensitive imaging of intracellular
microRNA (miR-21), achieving the rapid and precise detection of prostate
cancer. The multifunctional gold nanoprobe (GNP-DNA/Ab) was modified
by two types of prostate-specific antibodies, anti-PSMA and anti-EpCAM,
which could effectively recognize the targeting CTCs, and meanwhile
linked double-stranded DNA for further visually imaging intracellular
miR-21. Upon the specific internalization of GNP-DNA/Ab by PC-3 cells,
target aberrant miR-21 could displace the signal strand to recover
the fluorescence signal for sensitive detection at the single-cell
level, achieving single PC-3 cell imaging benefiting from the thermophoresis-mediated
signal amplification procedure. Taking advantage of the sensitive
miR-21 imaging performance, GNP-DNA/Ab could be employed to discriminate
the PC-3 and Jurkat cells because of the different expression levels
of miR-21. Notably, PC-3 cells were efficiently recognized from white
blood cells, exhibiting promising potential for the early diagnosis
of prostate cancer. Furthermore, GNP-DNA/Ab possessed good biocompatibility
and stability. Therefore, this work provides a great tool for aberrant
miRNA-related detection and specific discrimination of CTCs, achieving
the early and accurate diagnosis of prostate cancer.