Determination of Gold Ions in Human Urine Using Genetically Engineered Microorganisms on a Paper Device

This paper presents a whole-cell biosensor that operates in conjunction with a smartphone-based fluorescence diagnostic system on a paper device to monitor the concentration of gold ions in human urine. The heavy metal-tolerant bacteria Cupriavidus metallidurans was genetically engineered for use as a chassis in a red fluorescent protein (RFP)-based microbial sensor. The biosensor is highly sensitive to gold ions, with a detection limit of 110 nM. The proposed smartphone-based analysis system provides a user-friendly approach to design tools of personal health monitoring for reporting the presence of gold ions in human urine.