A flexible and highly sensitive organic electrochemical transistor-based biosensor for continuous and wireless nitric oxide detection.

As nitric oxide (NO) plays significant roles in a variety of physiological processes, the capability for real-time and accurate detection of NO in live organisms is in great demand. Traditional assessments of NO rely on indirect colorimetric techniques or electrochemical sensors that often comprise rigid constituent materials and can hardly satisfy sensitivity and spatial resolution simultaneously. Here, we report a flexible and highly sensitive biosensor based on organic electrochemical transistors (OECTs) capable of continuous and wireless detection of NO in biological systems. By modifying the geometry of the active channel and the gate electrodes of OECTs, devices achieve optimum signal amplification of NO. The sensor exhibits a low response limit, a wide linear range, high sensitivity, and excellent selectivity, with a miniaturized active sensing region compared with a conventional electrochemical sensor. The device demonstrates continuous detection of the nanomolar range of NO in cultured cells for hours without significant signal drift. Real-time and wireless measurement of NO is accomplished for 8 d in the articular cavity of New Zealand White rabbits with anterior cruciate ligament (ACL) rupture injuries. The observed high level of NO is associated with the onset of osteoarthritis (OA) at the later stage. The proposed device platform could provide critical information for the early diagnosis of chronic diseases and timely medical intervention to optimize therapeutic efficacy.

Metal Halide Perovskites for Optical Parametric Modulation.

Metal halide perovskites (MHPs) have attracted considerable academic and industrial attention because of their remarkable optoelectronic properties. The development of optical parametric modulation is urgently needed because it plays an important role in display applications and optical communication. Perovskites can become the bridge between materials and optics. Through changing the composition and nanostructure of perovskites, we can modulate optical parameters, including optical intensity, frequency, polarization, and phase. This Perspective provides a brief introduction to this field and summarizes the methods of modulating optical parameters. It is instructive for building a relationship between perovskite nanostructures and optics, which is meaningful for display technologies and optical communication.