Enzyme-coupled polymersome microreactor for point-of-care blood urea sensing

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Analytical Chemistry

Background:

• Vesicular microreactors are utilized in drug delivery and biodetoxification.
• Previous work developed ammonia-sensing polymersome microreactors for liver disease biomarkers.
• Poly(styrene)-b-poly(ethylene glycol) polymersomes exhibit selective membrane permeability.

Purpose of the Study:

• To develop a point-of-care blood urea sensor by coupling urease with ammonia-sensing polymersomes.
• To expand diagnostic applications of vesicular microreactors to urea detection in whole blood.
• To enable real-time urea monitoring for kidney disease management during hemodialysis.

Main Methods:

• Optimized assay components including polymersomes, pH-sensitive dye, and urease in phosphate buffer.
• Tested the urease-coupled polymersome assay in urea-spiked fresh mouse blood.
• Validated the assay in an IRB-approved study with healthy volunteers using capillary blood.

Main Results:

• The assay demonstrated a rapid and linear response at clinically relevant urea concentrations in mouse blood.
• The developed sensor successfully discriminated three clinically relevant spiked urea concentrations in human capillary blood within one minute.
• The combination of urease and ammonia-sensing polymersomes yielded a highly selective and rapid blood urea assay.

Conclusions:

• Coupling urease with ammonia-sensing polymersome microreactors enables effective blood urea sensing.
• This technology holds significant potential for point-of-care diagnostics of blood metabolites.
• The rapid and selective nature of the assay can improve kidney disease management by enabling real-time monitoring.