Electric-Field Pixel Array Biosensor for Catalytic Ion Detection in Diabetic Nephropathy

Area of Science:

• Biomedical Engineering
• Clinical Chemistry
• Point-of-Care Diagnostics

Background:

• Trimethylamine N-oxide (TMAO) is a biomarker for diabetic nephropathy and cardiovascular disease.
• Early detection and risk stratification are crucial for managing chronic kidney disease (CKD).

Purpose of the Study:

• To develop an electric-field-driven pixel array urine biosensor for assessing diabetic nephropathy.
• To elucidate the relationship between urine TMAO, glucose, and urine microalbumin-to-creatinine ratio (UACR).

Main Methods:

• Utilized trimethylamine N-oxide reductase (torA) enzyme to catalyze TMAO reduction, generating H+ ions that modulate the biosensor's electric field.
• Integrated a pixel array biosensor with a readout circuit for quantitative TMAO and glucose detection.
• Employed a small urine sample volume (5 μL) for simultaneous analysis.

Main Results:

• The biosensor achieved sensitive TMAO detection (8.2 mV/(mg/g)) over a wide UACR range (up to 1200 mg/g).
• Glucose levels showed poor correlation with progressive albuminuria above 30 mg/g UACR.
• The device demonstrated high sensitivity (2.5 mV/μM), rapid response (10 s), excellent reproducibility (98%), and low drift (0.3 mV).

Conclusions:

• The developed biosensor offers a rapid, sensitive, and user-friendly platform for early CKD risk assessment in diabetic patients.
• This point-of-care system facilitates improved accessibility for home-based monitoring of diabetic nephropathy.
• Simultaneous measurement of TMAO and glucose provides valuable insights into kidney health.