A novel urea sensitive biosensor with extended dynamic range based on recombinant urease and ISFETs

Area of Science:

• Biotechnology
• Biosensors
• Analytical Chemistry

Background:

• Urea monitoring is crucial for diagnosing kidney function and managing dialysis.
• Existing urea detection methods may lack the sensitivity or stability required for real-time clinical applications.

Purpose of the Study:

• To develop a novel urea biosensor utilizing immobilized recombinant urease and an ion-sensitive field-effect transistor (ISFET).
• To evaluate the performance characteristics of the developed biosensor for potential use in clinical urea analysis.

Main Methods:

• Photoimmobilization of recombinant urease (from E. coli) with an increased Km in a poly(vinyl alcohol)/styrylpyridinium (PVA/SbQ) membrane.
• Fabrication and characterization of enzymatic field-effect transistors (EnFETs) using the immobilized urease as the biorecognition element.
• Testing the biosensor in model buffer solutions to assess dynamic range, reproducibility, and stability.

Main Results:

• The developed urea biosensor demonstrated good performance with an extended dynamic range up to 80 mM.
• High reproducibility was observed, with a standard deviation of approximately 2.5% for sensor responses at 10 mM urea (n=20).
• The biosensor exhibited significant stability, meeting analytical requirements for urea control.

Conclusions:

• The novel urea biosensor based on photoimmobilized recombinant urease and ISFET is a promising analytical tool.
• Its performance characteristics, including extended dynamic range, reproducibility, and stability, are suitable for urea monitoring in plasma and dialysis fluids.
• This biosensor technology could enhance the management of patients with kidney disease.