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In this work, a microfluidic chip using Au@SiO2 array–based highly active SERS substrates was developed for quantitative detection of squamous cell carcinoma antigen (SCCA) and carcinoembryonic antigen (CEA) associated with cervical cancer. The chip consisted of six functional units with pump-free design, enabling parallel detection of multiple samples in an automatic manner without external pumps and improving the portability. Ag nanocubes (AgNCs) were labeled with Raman reporters and coupled with antibodies (labeling) to prepare SERS tags, while the Au nanoparticle–modified SiO2 microsphere (Au@SiO2) array was conjugated with antibodies (coating) to generate the highly SERS-active capturing substrate. In the presence of target biomarkers, they were captured by SERS tags and capturing substrate, resulting in the formation of "sandwich" structures which were trapped in the detection chamber. As the immune reaction proceeded, a large number of "hot spots" were generated by the proximity of the Au@SiO2 array substrate and AgNCs, greatly amplifying SERS signals. With this chip, the limits of detection of the SCCA and CEA levels in human serum were estimated to be as low as 0.45 pg mL−1 and 0.36 pg mL−1, respectively. Furthermore, the good selectivity and reproducibility of this chip were confirmed. Finally, clinical serum samples were analyzed by this chip, and the outcomes were consistent with those of enzyme-linked immunosorbent assay (ELISA). Thus, the proposed microfluidic chip can be potentially applied for the clinical diagnosis of cervical cancer. [ABSTRACT FROM AUTHOR]

Lung resident mesenchymal stem cells (LR-MSCs) are important regulators of pathophysiological processes including tissue repair and fibrosis, inflammation, angiogenesis and tumor formation. Therefore, increasing attention has focused on the functional differentiation of LR-MSCs. However, the distinction between the undifferentiated and differentiated LR-MSCs, which are closely related and morphologically similar, is difficult to achieve by conventional methods. In this study, by employing the TAT Peptide-conjugated Au nanostars (AuNSs) as an intracellular probe, we developed a method for the identification of LR-MSC differentiation by surface-enhanced Raman scattering (SERS) spectroscopy. SERS spectra were analyzed using principal component analysis (PCA) that allowed unambiguous distinction of subtypes and monitoring of component changes during cellular differentiation. Furthermore, to ascertain whether co-culture with alveolar epithelial type II (ATII) cells and incubation with transform growth factor (TGF)-β were involved in regulating the differentiation of LR-MSCs, we investigated the protein expression levels of epithelial markers and fibroblastic markers on LR-MSCs. Our results demonstrated that co-culture with ATII cells or incubation with TGF-β could induce the differentiation of LR-MSCs as confirmed by SERS analysis, a method that is capable of noninvasive characterization of and distinction between subtypes of LR-MSCs during differentiation. We have provided a new tool that may facilitate stem cell research. [ABSTRACT FROM AUTHOR]