Prostate cancer cell-derived exosomes in urine have been extensively studied recently and regarded as novel biomarkers for cancer diagnosis and prognosis, which presents wide prospects in clinical applications. Sensitive detection and specific capture methods are essential for exosomes analysis. Herein, a dual functional platform composed of superparamagnetic conjunctions and molecular beacons (SMC-MB) is reported. The SMC-MB platform is designed based on aptamer immunoaffinity with ultrasensitive detection efficiency and reversible isolation capacity, which, respectively, profit from nonenzymatic amplification methods and magnetic separation along with restriction cleavage. It is noteworthy that exosomes quantification was exactly amplified and transformed into single strand DNA detection. Correlated measurements evidence that the limit of detection of SMC-MB is as low as ∼100 particles/μL in urine, and a linear relationship meets between the logarithmic concentration of exosomes and fluorescence intensity of the molecular beacon. Furthermore, employing prostate specific membrane antigen (PSMA) aptamer, the platform adapted to detect and capture PMSA-positive exosomes from urine samples provides excellent diagnostic efficiency for prostate cancer (PCa). The expression of typical biomarkers of PCa, i.e., PSA and PCA3 mRNA, is significantly higher in PSMA-positive exosomes. Altogether, the platform and strategy described in this paper are promising in urinary exosomes analysis and prostate cancer detection.

Breast cancer metastasis remains the primary cause of death and efforts to predict and reduce metastatic risk are particularly appealing. CXC chemokine receptor 4 (CXCR4) is reported as a specific metastasis due to its chemotactic homing to CXCL12. Herein, conjugation of a CXCR4 antagonist, AMD3100, to a fluorescent silver sulfide quantum dot (Ag 2 S) core (QD-AMD) allows accurate detection of CXCR4 expression in tumor. Particularly, the probe precisely distinguishes highly metastatic breast cancer cells from those of lower metastatic ability. Longitudinal in vivo imaging predicts at early stages that the high CXCR4 expressing orthotopic 4T1 tumor would subsequently metastasize to lungs 14 d after tumor inoculation, while no metastasis forms from the low CXCR4 expressing MCF-7 tumor. Correlative measurements find that the CXCL12 levels in lung increase with tumor progression. Perturbations of either CXCR4 on tumor cells by QD-AMD or CXCL12 in the lungs by antibody successfully inhibit cancer metastasis. Intravenous injection of QD-AMD in primary 4T1 tumor model effectively reduces lung metastasis. More importantly, due to the intrinsic photothermal effect, the metastatic spread is more thoroughly abrogated along with substantial shrinkage of primary tumor. Altogether, the probe is promising to detect, predict, and inhibit the metastatic spread of breast tumor.

Gene mutation profiling of heterogeneous circulating tumor cells (CTCs) offers comprehensive and real-time molecular information of tumors for targeted therapy guidance, but the lack of efficient and multiplex genotyping techniques for single-CTC analysis greatly hinders its development and clinical application. This paper reports a single-CTC mass spectrometry analysis method for efficient and multiplex mutation profiling based on digital microfluidics. Digital microfluidics affords integrated single-CTC manipulation, from single-CTC isolation to high-performance whole genome amplification, via nanoliter droplet-based wettability trapping and hydrodynamic adjustment of cell distribution. Coupled with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, multiplex mutation information of individual CTCs can be efficiently and accurately identified by the inherent mass differences of different DNA sequences. This platform achieves Kirsten rat sarcoma viral oncogene mutation profiling of heterogeneous CTCs at the single-cell level from cancer patient samples, offering new avenues for genotype profiling of single CTCs and cancer therapy guidance.

Circulating fetal nucleated cells (CFCs) carrying whole genomic coding of the fetus in maternal blood have been pursued as ideal biomarkers for noninvasive prenatal testing (NIPT). However, a significant limitation is the need to enrich sufficient cells in quantity and purity for fetal genetic disorder diagnosis. This study for the first time demonstrates a stimuli-responsive ligand enabling interface on array patterned microfluidic chip (NIPT-Chip) for high efficient isolation and release of CFCs in untreated whole blood. Deterministic lateral displacement (DLD)-array was patterned in the chip to increase collision frequency between CFCs and surface-anchored antibody to achieve high efficient cell capture. More importantly, the stimuli-responsive interface enables gentle release of captured CFCs through a thiol exchange reaction for downstream gene analysis of NIPT. With the advantages of simple processing, efficient isolation, and gentle release, NIPT-Chip offers great potential for clinical translation of circulating fetal cell-based NIPT.