As a new type of environmental pollutant, microplastics (MPs) can adsorb residual organochlorine pesticides (OCPs) in the soil and pose a severe threat to the soil ecosystems. To understand the interaction between soil MPs and OCPs, the sorption of two kinds of OCPs, including hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs), on polyethylene (PE) microplastics in soil suspension was studied through sorption kinetics and isotherm models. The effects of solution/soil ratio and MPs diameter on sorption were examined. The kinetic experiment results show that the sorption equilibrium was 12 h， and the sorption process of OCPs on MPs can be well described by a pseudo-second-order model. The Freundlich model (R² = 0.942-0.997) provides a better fit to the sorption isotherm data than the Langmuir model (R² = 0.062-0.634), indicating that the sorption process takes place on the nonuniform surface of MPs. The MPs had a good sorption effect on OCPs when the solution/soil ratio was from 75:1 to 100:1. As the diameter of MPs increases, the sorption capacity decreases. These results provide support for further research on microplastic pollution in soil.

Circulating tumor cells (CTCs) have been proposed to be an active source of metastasis or recurrence of hepatocellular carcinoma (HCC). The enumeration and characterization of CTCs has important clinical significance in recurrence prediction and treatment monitoring in HCC patients. We previously developed a unique method to separate HCC CTCs based on the interaction of the asialoglycoprotein receptor (ASGPR) expressed on their membranes with its ligand. The current study applied the ligand-receptor binding assay to a CTC-chip in a microfluidic device. Efficient capture of HCC CTCs originates from the small dimensions of microfluidic channels and enhanced local topographic interactions between the microfluidic channel and extracellular extensions. With the optimized conditions, a capture yield reached > 85% for artificial CTC blood samples. Clinical utility of the system was further validated. CTCs were detected in all the examined 36 patients with HCC, with an average of 14 ± 10/2 mL. On the contrary, no CTCs were detected in healthy, benign liver disease or non-HCC cancer subjects. The current study also successfully demonstrated that the captured CTCs on our CTC-chip were readily released with ethylene diamine tetraacetic acid (EDTA); released CTCs remained alive and could be expanded to form a spheroid-like structure in a 3-dimensional cell culture assay; furthermore, sensitivity of released CTCs to chemotherapeutic agents (sorafenib or oxaliplatin) could be effectively tested utilizing this culture assay. In conclusion, the methodologies presented here offer great promise for accurate enumeration and easy release of captured CTCs, and released CTCs could be cultured for further functional studies.