Conductive Polymer-Coated Carbon Nanotubes To Construct Stretchable and Transparent Electrochemical Sensors.

Carbon nanotube (CNT)-based flexible sensors have been intensively developed for physical sensing. However, great challenges remain in fabricating stretchable CNT films with high electrochemical performance for real-time chemical sensing, due to large sheet resistance of CNT film and further resistance increase caused by separation between each CNT during stretching. Herein, we develop a facile and versatile strategy to construct single-walled carbon nanotubes (SWNTs)-based stretchable and transparent electrochemical sensors, by coating and binding each SWNT with conductive polymer. As a polymer with high conductivity, good electrochemical activity, and biocompatibility, poly(3,4-ethylenedioxythiophene) (PEDOT) acting as a superior conductive coating and binder reduces contact resistance and greatly improves the electrochemical performance of SWNTs film. Furthermore, PEDOT protects the SWNTs junctions from separation during stretching, which endows the sensor with highly mechanical compliance and excellent electrochemical performance during big deformation. These unique features allow real-time monitoring of biochemical signals from mechanically stretched cells. This work represents an important step toward construction of a high performance CNTs-based stretchable electrochemical sensor, therefore broadening the way for stretchable sensors in a diversity of biomedical applications.

N,S-Codoped Carbon Dots with Red Fluorescence and Their Cellular Imaging.

The emergence of carbon dots (C-dots) has aroused increasing attention owing to their excellent chemical and physical properties, such as favorable biocompatibility and an outstanding fluorescence (FL) property. Most reported C-dots show blue emission, which hinders their applications in the biomedical field due to the strong FL background of biosamples. Therefore, strategies for the achievement of long-wavelength fluorescent C-dots are urgently needed. Herein, red emissive biocompatible C-dots were prepared from polythiophene (PTh) through chemical cutting by nitric acid. Various methods were utilized to shed light on the luminescence mechanism of the C-dots. The results demonstrated that FL emission of the prepared C-dots was mainly dominated by sp2 domains. The C-dots were well-applied in in vitro imaging. This work prepared red fluorescent C-dots from the perspective of the structure of C-dots, which would benefit the regulation of the FL of C-dots.

Photoresponsive immunomagnetic nanocarrier for capture and release of rare circulating tumor cells.

Isolation, release and culture of rare circulating tumor cells (CTCs) may, if implemented, promote the progress of individualized anti-tumor therapies. To realize the release of CTCs without disruption of their viability for further culture and analysis, we designed an effective photocontrolled CTC capture/release system by combination of photochemistry and immunomagnetic separation. 7-Aminocoumarin was synthesized as the phototrigger to bridge the connection between the anti-EpCAM antibody and the magnetic beads. The coumarin moieties produced cleavage of a C-O bond under both ultraviolet (UV) and near-infrared (NIR) light illumination, breaking the bridge and releasing CTCs from the immunomagnetic beads. Compared with conventional immunomagnetic separation systems, the negative influence of absorbed immunomagnetic beads on further CTCs culture and analysis was effectively eliminated. The system can specifically recognize 102 MCF-7 cells in 1 mL of human whole blood samples with 90% efficiency and 85% purity. Under the irradiation of UV and NIR light, 73 ± 4% and 52 ± 6% of captured cells were released with a viability of 90% and 97%, respectively. Furthermore, this technique has been used to detect CTCs from whole blood of cancer patients with high purity. This study demonstrates that the photochemical-based immunomagnetic separation method for isolating, releasing and culturing CTCs from clinic patients may provide new opportunities for cancer diagnosis and personalized therapy.