Liquid Metal pH Morphology Sensor Used for Biological Microenvironment Detection.

Area of Science:

• Biomedical Engineering
• Materials Science
• Electrochemistry

Background:

• Monitoring the pH of biological microenvironments is crucial for understanding cell metabolism and life cycles.
• Liquid metals (LMs) exhibit sensitivity to hydrogen ions, presenting an opportunity for novel sensing applications.

Purpose of the Study:

• To develop a facile pH sensor utilizing the morphological changes of liquid gallium (LM) droplets.
• To investigate the pH sensing characteristics and mechanism of LM droplets.

Main Methods:

• Examined the shape response of LM droplets across a range of pH values.
• Investigated the electrochemical properties of LM in solutions of varying pH.
• Analyzed the formation and removal of the native oxide skin on LM and its effect on surface tension.
• Calibrated the relationship between LM morphology and pH, and assessed interference from impurity ions.

Main Results:

• LM droplet morphology significantly changes in response to pH variations due to alterations in surface tension caused by oxide layer removal.
• A reliable calibration curve correlating LM morphology with pH was established.
• A detection algorithm was developed, enabling automated pH detection via a mobile app.

Conclusions:

• Liquid gallium droplet morphology change is a viable readout for a novel, facile pH sensor.
• The developed sensor was successfully applied to detect the pH of cell culture solutions.
• LM's response to hydrogen ions holds significant potential for microenvironment monitoring applications.