pH Sensors, Biosensors and Systems

This Topical Collection Reprint has gathered the latest findings in sensors, biosensors, and technologies, with a special attention systems where the pH plays a prominent role. The pH value is crucial for many living systems and chemical reactions in nature. Biology and microbiology (e.g., monitoring of bacteria, DNA, enzymes, aminoacids, and cells), environmental protection (e.g., characterization of waste and sea water), food and beverage quality control (e.g., monitoring of fermentation processes and the characterization of fruit, drinking water, and vegetables), pharmaceutics, cosmetics (quality control of creams, gels, and shampoos), medicine (e.g., monitoring and analysis of culture media, cancer, blood, and cytoplasm), and industry (e.g., chemical baths for paints and plating) are some of the fields where pH sensors have been extensively used to understand the nature of chemical processes, as well as to monitor quality and control safety. Although paper test strips and glass electrodes are the most common pH sensors, many studies have focused on developing less fragile, miniaturized, and biocompatible sensors with higher sensitivity. The pH value can be measured through various approaches and materials, including electrochemical and optical sensors, ion-selective field effect transistors (ISFETs), quantum dots, 2D materials, and organic compounds.