PHAIR: a biosensor for pH measurement in air-liquid interface cell culture

Current and future technologies for monitoring cultured meat: A review

The high population growth rate, massive animal food consumption, fast economic progress, and limited food resources could lead to a food crisis in the future. There is a huge requirement for dietary proteins including cultured meat is being progressed to fulfill the need for meat-derived proteins in the diet. However, production of cultured meat requires monitoring numerous bioprocess parameters. This review presents a comprehensive overview of various widely adopted techniques (optical, spectroscopic, electrochemical, capacitive, FETs, resistive, microscopy, and ultrasound) for monitoring physical, chemical, and biological parameters that can improve the bioprocess control in cultured meat. The methods, operating principle, merits/demerits, and the main open challenges are reviewed with the aim to support the readers in advancing knowledge on novel sensing systems for cultured meat applications.

Liquid Metal pH Morphology Sensor Used for Biological Microenvironment Detection

pH is one of the important parameters of a biological microenvironment, which is closely related to cell growth, development, vitality, division, and differentiation. Monitoring the pH of a microenvironment is helpful to monitor the cell metabolism as well as to understand the cellular life cycle. The sensitivity of liquid metals (LMs) to hydrogen ions has aroused our interest. Here, we propose a novel but facile pH sensor using liquid gallium (LM for short) droplet morphological change as the readout. The pH sensing characteristics of the LM droplet were examined, especially the shape response. LM can form solid native oxide skin rapidly in oxygenated solution, and the oxide layer will be removed in acidic or alkaline solutions, which will cause a great change in surface tension. The phenomenon is the change of LM morphology from macroscopic observation. We explored the electrochemical characteristics of LM at different pH values, explained the mechanism of surface change, and calibrated the relationship curve between LM morphology and pH and the interference of impurity ions on the sensor. Finally, we proposed a detection algorithm for the LM pH morphology sensor and tried to automatically detect pH with a mobile app, which was applied to the pH detection of cell culture solution. We believe that the response characteristics of LM to hydrogen ions have great potential in microenvironment detection.