A portable gas sensor based on In2O3@CuO P-N heterojunction connected via Wi-Fi to a smartphone for real-time carbon monoxide determination.

This research presents a compact portable electronic gas sensor that can be monitored through a smartphone application. The smart sensor utilizes three state-of-the-art sensors. The sensors integrate an ESP8266 microcontroller within the same device. This facilitates their integration with the electronics and enhances their performance. Herein, primarily focuses on utilizing the sensor to detect carbon monoxide. This article outlines the fabrication process of a gas sensor utilizing a P-N heterojunction, eliminating the need for a binder. The sensor consists of CuO/copper foam nanowires and hierarchical In2O3. In order to verify the system's functionality, it underwent testing with various levels of CO concentrations (10-900 ppm), including particular tests designed to examine the device's performance in different humidity and temperature circumstances. A mobile application for the provision of monitoring services has been developed at last. To process the information obtained from the gas sensor, an algorithm has been constructed, trained, and integrated into a smartphone for this purpose. This research demonstrated that a smartphone-coupled gas sensor is a viable system for real-time monitoring and the detection of CO gas.

Wireless wearable potentiometric sensor for simultaneous determination of pH, sodium and potassium in human sweat.

This paper reports on the development of a flexible-wearable potentiometric sensor for real-time monitoring of sodium ion (Na+), potassium ion (K+), and pH in human sweat. Na0.44MnO2, polyaniline, and K2Co[Fe(CN)6] were used as sensing materials for Na+, H+ and K+ monitoring, respectively. The simultaneous potentiometric Na+, K+, and pH sensing were carried out by the developed sensor, which enables signal collection and transmission in real-time to the smartphone via a Wi-Fi access point. Then, the potentiometric responses were evaluated by a designed android application. Na+, K+, and pH sensors illustrated high sensitivity (59.7 ± 0.8 mV/decade for Na+, 57.8 ± 0.9 mV/decade for K+, and 54.7 ± 0.6 mV/pH for pH), excellent stability, and good batch-to-batch reproducibility. The results of on-body experiments demonstrated that the proposed platform is capable of real-time monitoring of the investigated ions.

Penaeus vannamei protease activating mechanism of sulfhydryl reducing compounds.

For the very first time, protease enzyme from Penaeus vannamei was investigated for its activation with thiol reductant compounds. The mechanism by which sulfhydryl reductant compounds enhances the activity of P. vannamei protease still remains unclear. In this study, it was discovered that thiol-reactive compounds increase P. vannamei protease activity by a factor of about 4 with increasing Vmax and decreasing Km parameters. Moreover, the reaction is an SN2-type that does not require the initial binding of the thiol group of these compounds to the enzyme. Additionally, k2 increased appreciably with increasing concentration of sulfhydryl reductant compounds. The linearity of this plot indicates that k1 is unaffected by the addition of thiol compounds. Hence, the observed effect of thiol compounds on Km seems to be due to an increase in k2. These results suggest that the activation mechanism of P. vannamei protease almost certainly takes place by an SN2 reaction mechanism.