Photoredox Catalysis for the Fabrication of Water-Repellent Surfaces with Application for Oil/Water Separation.

Silanization processes with perfluoroalkyl silanes have been demonstrated to be effective in developing advanced materials with many functional properties, including hydrophobicity, water repellency, and self-cleaning properties. However, practical industrial applications of perfluoroalkyl silanes are limited by their extremely high cost. On the basis of our recent work on photoredox catalysis for amidation with perfluoroalkyl iodides, its application for surface chemical modification on filter paper, as an illustrative example, has been developed and evaluated. Before photocatalytic amidation, the surface is functionalized with amine functional groups by silanization with 3-(trimethoxysilyl)propylamine. All chemically modified surfaces have been fully characterized by attenuated total reflection infrared (ATR-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), and three-dimensional (3D) profiling to confirm the successful silanization and photocatalytic amidation. After surface modification of the filter papers with perfluoroalkanamide, they show high water repellency and hydrophobicity with contact angles over 120°. These filter papers possess high wetting selectivity, which can be used to effectively separate the organic and aqueous biphasic mixtures. The perfluoroalkanamide-modified filter papers can be used for separating organic/aqueous biphasic mixtures over many cycles without lowering the separating efficiency, indicating their reusability and excellent durability.

Highly Sensitive and Cost-Effective Portable Sensor for Early Gastric Carcinoma Diagnosis.

Facile and efficient early detection of cancer is a major challenge in healthcare. Herein we developed a novel sensor made from a polycarbonate (PC) membrane with nanopores, followed by sequence-specific Oligo RNA modification for early gastric carcinoma diagnosis. In this design, the gastric cancer antigen CA72-4 is specifically conjugated to the Oligo RNA, thereby inhibiting the electrical current through the PC membrane in a concentration-dependent manner. The device can determine the concentration of cancer antigen CA72-4 in the range from 4 to 14 U/mL, possessing a sensitivity of 7.029 µAU-1mLcm-2 with a linear regression (R2) of 0.965 and a lower detection limit of 4 U/mL. This device has integrated advantages including high specificity and sensitivity and being simple, portable, and cost effective, which collectively enables a giant leap for cancer screening technologies towards clinical use. This is the first report to use RNA aptamers to detect CA72-4 for gastric carcinoma diagnosis.

Gating a Single Cell: A Label-Free and Real-Time Measurement Method for Cellular Progression.

There is an ever-growing need for more advanced methods to study the response of cancer cells to new therapies. To determine cancer cells' response from a cell-mortality perspective to various cancer therapies, we report a label-free and real time method to monitor the in situ response of individual HeLa cells using a single cell gated transistor (SCGT). As a cell undergoes apoptotic cell death, it experiences changes in morphology and ion concentrations. This change is well in line with the threshold voltage of the SCGT, which has been verified by correlating the data with the cell morphologies by scanning electron microscopy and the ion-concentration analysis by inductively-coupled plasma mass spectrometry (ICPMS). This SCGT could replace patch clamps to study single cell activity via direct measurement in real time. Importantly, this SCGT can be used to study the electrical response of a single cell to stimuli that leaves the membrane intact.

Simultaneous Enhancement of Thermopower and Electrical Conductivity through Isovalent Substitution of Cerium in Bismuth Selenide Thermoelectric Materials.

It is challenging to achieve highly efficient thermoelectric materials due to the conflicts between thermopower (Seebeck coefficient) and electrical conductivity. These parameters are the core factors defining the thermoelectric property of any material. Here, we report the use of isovalent substitution as a tool to decouple the interdependency of the Seebeck coefficient and the electrical properties of cerium-doped bismuth selenide thermoelectric material. With this strategy, we can achieve a simultaneous increase in both the electrical conductivity and the Seebeck coefficient of the material by tuning the concentration of cerium doping, due to formation of neutral impurities and consequently the improvement of carrier mobility. Our theoretical calculation reveals a downward shift of the valence band with cerium concentration, which influences the thermoelectric enhancement of the synthesized materials. Finally, an order of magnitude enhancement of the figure of merit is obtained due to isovalent substitution, thus providing a new avenue for enhancing the thermoelectric performance of materials.