Concanavalin A (Con A) has been widely used as glucose recognition element in glucose sensors, however, these sensors typically detect glucose by fluorescence, and suffer from laborious labeling processes. Here a new label-free optical Con A-based glucose sensor was designed. The sensor uses Con A-containing thin hydrogel films as sensing material and Fabry-Perot cavity simultaneously, which were fabricated by layer-by-layer assembly of Con A and dextran, using lectin-saccharide biospecific interaction as driving force. These films display Fabry-Perot fringes on their reflection spectra, from which optical path length of the films can be calculated. The films swell upon addition of glucose, which causes a shift of Fabry-Perot fringes on the reflection spectra of the film, from which the glucose concentration can be reported. The glucose-induced swelling is reversible, and the increase in optical path length increases linearly with glucose concentration over a wide range of glucose concentration. The sensor works well at physiological temperature, pH and ionic strength. Other sugars, which may present in blood, do not interfere with glucose detection, because of their very low concentrations in the blood. Particularly, unlike other hydrogel-based sensors, this sensor responds quite fast, because the hydrogel films are very thin. The new sensor may have potential for real time, continuous glucose monitoring.
Shanshan Yan,Kaiyang Wang,Guichuan Xing,Jincheng Xu,Shichen Su,Zikang Tang,Shuangpeng Wang,Kar Wei Ng
Hybrid organic–inorganic lead halide perovskite microwires are potential building blocks for realizing on-chip integrated optoelectronic devices. However, the length-controllable synthesis of one-dimensional hybrid perovskite microwires has been rarely reported, especially the ones with lengths in the millimeter scale. Herein, methylammonium lead bromide (MAPbBr3) and formamidinium lead bromide (FAPbBr3) micro and milliwires are demonstrated using single-crystal PbBr2 microwires synthesized via template-free solution-phase growth as the lattice framework. Following the PbBr2 template, the as-converted perovskite microwires possess controllable lengths ranging from tens to thousands of micrometers. In addition, Fabry–Perot (FP) lasing was realized in both MAPbBr3 and FAPbBr3 microwires, attesting to their excellent crystal quality and the efficient optical confinement of the natural cavity. These unique properties result in the first demonstration of FP perovskite microwire lasers with submillimeter lengths. More interestingly, the microwire lasers show excellent photostability under repetitive pulsed laser excitation for over 8 × 106 cycles. Such findings demonstrate that the solution-converted hybrid lead bromide microwires have excellent optoelectronic performances promising for practical applications, and the size controllability indicates that this novel fabrication process may be feasible for large-scale industrial production.
危险品化学品经营许可证（带存储）