Smartphone-based portable photoelectrochemical biosensing system for point-of-care detection of urine creatinine and albumin

Creatinine and albumin are crucial biomarkers for health monitoring and their ratio in urine is an effective approach for albuminuria assessment. Herein, to address the challenges of point-of-care and efficient analysis of the biomarkers simultaneously, we developed a fully integrated handheld smartphone-based photoelectrochemical biosensing system. A miniaturized printed circuit board included a potentiostat for photocurrent measurements and single-wavelength light-emitting diodes (LEDs) for photo-excitation, which was controlled with a Bluetooth-enabled smartphone. Graphitic carbon nitride (g-C3N4)/chitosan nanocomposites were modified on a transparent indium tin oxide (ITO) electrode as photoactive materials. Creatinine was detected through chelate formation with copper ion probes, while albumin was recognized specifically by an antigen-antibody reaction based on immunoassay. The biosensing system demonstrated good linearity and high sensitivity, with detection ranges of 100 & mu;g mL(-1) to 1500 & mu;g mL(-1) for creatinine, and 9.9 & mu;g mL(-1) to 500 & mu;g mL(-1) for albumin. Spiked artificial urine samples with different concentrations were tested to confirm the practical validity of the biosensing system, where an acceptable recovery rate ranged from 98.7% to 105.3%. This portable photoelectrochemical biosensing platform provides a convenient and cost-effective method for biofluid analysis, which has an extensive prospect in point-of-care testing (POCT) for mobile health.

Automated summary

In this study, a fully integrated handheld smartphone-based photoelectrochemical biosensing system was developed for simultaneous analysis of creatinine and albumin, which are crucial biomarkers for health monitoring. The system utilized graphitic carbon nitride (g-C3N4)/chitosan nanocomposites modified on a transparent indium tin oxide (ITO) electrode as photoactive materials to detect creatinine through chelate formation with copper ion probes, and recognize albumin specifically by an antigen-antibody reaction based on immunoassay. The biosensing system showed good linearity and high sensitivity, with detection ranges of 100μg mL(-1) to 1500μg mL(-1) for creatinine, and 9.9μg mL(-1) to 500μg mL(-1) for albumin. The practical validity of the system was confirmed through testing spiked artificial urine samples with acceptable recovery rates ranging from 98.7% to 105.3%. This portable photoelectrochemical biosensing platform provides a convenient and cost-effective method for biofluid analysis, with promising prospects in point-of-care testing (POCT) for mobile health.