A nanostructured platform that combines electrospun TiO(2) nanofibers (TiNFs)-deposited substrate and cell-capture agent realizes significant capture of circulating tumor cells (CTCs). The enhanced local topographic interactions between the horizontally packed TiNFs deposited substrates and extracellular matrix scaffolds, in addition to anti-EpCAM/EpCAM biological recognition, contributes to the significantly enhanced capture efficiency compared to flat surfaces.

Contact electrification between water and a solid surface is crucial for physicochemical processes at water–solid interfaces. However, the nature of the involved processes remains poorly understood, especially in the initial stage of the interface formation. Here we report that H 2 O 2 is spontaneously produced from the hydroxyl groups on the solid surface when contact occurred. The density of hydroxyl groups affects the H 2 O 2 yield. The participation of hydroxyl groups in H 2 O 2 generation is confirmed by mass spectrometric detection of 18 O in the product of the reaction between 4-carboxyphenylboronic acid and 18 O–labeled H 2 O 2 resulting from 18 O 2 plasma treatment of the surface. We propose a model for H 2 O 2 generation based on recombination of the hydroxyl radicals produced from the surface hydroxyl groups in the water–solid contact process. Our observations show that the spontaneous generation of H 2 O 2 is universal on the surfaces of soil and atmospheric fine particles in a humid environment.

Organic electrochemical transistors (OECTs) are successfully used for the detection of bacteria (E. coli O157:H7) in KCl electrolytes. The transfer characteristic of the OECT shifts to higher gate voltage after bacteria are captured on the active layer of the device, which can be attributed to the electrostatic interaction between the bacteria and the transistor. The OECT with a Pt gate electrode shows a voltage shift of up to 55 mV after the capture of bacteria. The influence of the ion concentration of the electrolyte on the device performance is also studied. It is expected that the organic transistors will find promising applications as disposable bacteria sensors.

Aiming to highly efficient capture and analysis of circulating tumor cells, a micropillar device decorated with graphite oxide-coated magnetic nanoparticles is developed for magneto-controllable capture and release of cancer cells. Graphite oxide-coated, Fe3 O4 magnetic nanoparticles (MNPs) are synthesized by solution mixing and functionalized with a specific antibody, following by the immobilization of such modified MNPs on our designed micropillar device. For the proof-of-concept study, a HCT116 colorectal cancer cell line is employed to exam the capture efficiency. Under magnetic field manipulation, the high density packing of antibody-modified MNPs on the micropillars increases the local concentration of antibody, as well as the topographic interactions between cancer cells and micropillar surfaces. The flow rate and the micropillar geometry are optimized by studying their effects on capture efficiency. Then, a different number of HCT116 cells spiked in two kinds of cell suspension are investigated, yielding capture efficiency >70% in culture medium and >40% in blood sample, respectively. Moreover, the captured HCT116 cells are able to be released from the micropillars with a saturated efficiency of 92.9% upon the removal of applied magnetic field and it is found that 78% of the released cancer cells are viable, making them suitable for subsequent biological analysis.