Highly dense nickel hydroxide nanoparticles catalyst electrodeposited from a novel Ni(II) paddle–wheel complex

Microliter Sample Insulin Detection Using a Screen-Printed Electrode Modified by Nickel Hydroxide

The monitoring of insulin, which is the only hormone that helps regulate blood glucose levels in the body, plays a key role in the diagnosis and treatment of diabetes. However, most techniques today involve complicated electrode fabrication and testing processes, which are time-consuming and costly, and require a relatively large volume of sample. To overcome these drawbacks, we present here a low-cost insulin detection method based on a screen-printed electrode (SPE) modified by nickel hydroxide (Ni(OH)₂). This novel method only requires 300 μL of insulin sample, and the time it takes for electrode preparation is about 12 times shorter than traditional electrode fabrication methods such as coating and sol-gel methods. The electrochemical behaviors of the Ni(OH)₂-coated SPE (NSPE) sensing area in insulin aqueous solutions are studied using cyclic voltammetry, amperometric i-t curves, and electrochemical impedance spectroscopy. The results demonstrate that the NSPE sensing surface has excellent detection properties, such as a high sensitivity of 15.3 μA·μM^-1 and a low detection limit of 138 nM. It takes a short time (∼10 min) to prepare the NSPE sensing surface, and only two drops (∼300 μL) of insulin samples are required in the detection process. Moreover, the selectivity of this method for insulin detection is verified by detecting mixtures of insulin and ascorbic acid or bovine hemoglobin. Finally, we discuss the potential clinical applications of this method by detecting various concentrations of insulin in human serum.

Sensors Based on Bio and Biomimetic Receptors in Medical Diagnostic, Environment, and Food Analysis

Analytical chemistry is now developing mainly in two areas: automation and the creation of complexes that allow, on the one hand, for simultaneously analyzing a large number of samples without the participation of an operator, and on the other, the development of portable miniature devices for personalized medicine and the monitoring of a human habitat. The sensor devices, the great majority of which are biosensors and chemical sensors, perform the role of the latter. That last line is considered in the proposed review. Attention is paid to transducers, receptors, techniques of immobilization of the receptor layer on the transducer surface, processes of signal generation and detection, and methods for increasing sensitivity and accuracy. The features of sensors based on synthetic receptors and additional components (aptamers, molecular imprinted polymers, biomimetics) are discussed. Examples of bio- and chemical sensors' application are given. Miniaturization paths, new power supply means, and wearable and printed sensors are described. Progress in this area opens a revolutionary era in the development of methods of on-site and in-situ monitoring, that is, paving the way from the "test-tube to the smartphone".

Quasi-1D chains of dinickel lantern complexes and their magnetic properties

Four new quasi-1D Ni₂lantern chain complexes of the form [Ni₂(SOCR)₄(L)]_∞were prepared withN,N′-donor bridging ligands pyrazine and DABCO.