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Epithelial-mesenchymal transition (EMT) is critically involved in a variety of biological processes. Electrochemical sensing offers potential to develop more effective technology for EMT detection. In this study, by using the unique performance of quantum dot (QD)-nanocomposite materials, we establish an electrochemical biosensor that can specifically detect the change of E-cadherin and analyze different stages of EMT. The signal for EMT is largely magnified due to the transmission of molecular information to the electronic device. In addition, differential pulse voltammetry reveals that the response of the electrochemical signals is rapid and sensitive, due to the synergistic effect of QDs and carbon nanotube-gold nanoparticles. Our study thus suggests that electrochemical sensing is an effective technology for detecting EMT and may have broad applications in analyzing various cell type transitions.

The methanolysis of poly(lactic acid) (PLA) was studied by using acidic ionic liquids (ILs) as catalyst in detail. The results showed that HSO 3 -functionalized ILs exhibited higher catalytic activity than non-functionalized ILs and traditional acid catalyst such as H 2 SO 4 . The influences of experimental parameters, such as the amount of catalyst, reaction temperature, methanolysis time, and dosages of methanol on the conversion of PLA, yield of methyl lactate were investigated. Under the optimal conditions, using 1methyl-3-(3-sulfopropyl)-immidazolium hydrogen sulfate ([HSO 3 -pmim][HSO 4 ]) as catalyst, the IL could be reused up to six times without apparent decrease in the conversion of PLA and yield of methyl lactate. The kinetics of the reaction was also investigated. The results indicated that the methanolysis of PLA in [HSO 3 -pmim][HSO 4 ] was a first-order kinetic reaction with activation energy of 47.01 kJ/mol and Arrhenius constant of 2.7 3 10 7 min 21 .

As a tumor marker, carbohydrate antigen 24-2 (CA242) is a highly accurate and specific diagnostic indicator for monitoring pancreatic and colorectal cancers. The goal of this study was to create a novel label-free electrochemical immunosensor using a nanocomposite glassy carbon electrode for the detection of CA242. Graphene oxide (GO) and polyvinyl pyrrolidone were chosen as the dopants for the preparation of a high-performance reduced-GO-gold-palladium (rGO-Au-Pd) nanocomposite. RGO-Au-Pd was characterized using X-ray diffraction and transmission electron microscopy, revealing that the material exhibited superior electrochemical redox activity and electron transfer ability. The effects of the synthesis method, material concentration, reduction cycle, and pH were investigated to optimize the performance of the immunosensor. As a result of the catalytic activity and biocompatibility of rGO-Au-Pd, the prepared CA242 immunosensor displayed a wide linear range of detection from 0.001 U/mL to 10,000 U/mL with a detection limit of 1.54 × 10−3 U/mL and a sensitivity of 4.24 μA (log10CCA242)−1. More importantly, the immunosensor exhibited satisfactory reproducibility and selectivity when detected CA242 in PBS or human serum. The results of our study provide a platform for the development of novel bioassays for use in early cancer diagnosis and promote the application of biosensing technology in the medical field.