Cellulose microfluidic pH boosting on copper oxide non-enzymatic glucose sensor strip for neutral pH samples

Area of Science:

• Electrochemistry
• Materials Science
• Biomedical Engineering

Background:

• Non-enzymatic glucose sensors offer advantages over enzymatic counterparts but are often limited by optimal pH requirements.
• Accurate glucose monitoring is crucial for diabetes management, necessitating reliable and accessible sensing technologies.

Purpose of the Study:

• To adapt a non-enzymatic copper oxide glucose sensor for operation at neutral pH using a microfluidic pH boosting layer.
• To enable in-situ glucose measurements in samples with neutral pH, including human blood.

Main Methods:

• Fabrication of a cellulose-based microfluidic layer containing sodium hydroxide (NaOH) crystals.
• Integration of the microfluidic layer with a three-electrode system (copper oxide working electrode, silver reference, carbon counter).
• Testing the system's performance in electrochemical cells and sensing strips with varying glucose concentrations.

Main Results:

• The microfluidic layer successfully dissolved NaOH crystals, increasing the sample pH and enabling non-enzymatic glucose detection.
• The adapted sensor demonstrated a sensitivity of 70 μA/mM cm² for glucose measurement in neutral pH samples.
• The system effectively distinguished between hypoglycemia and hyperglycemia levels in human blood samples.

Conclusions:

• A cellulose microfluidic pH boosting layer effectively adapts non-enzymatic copper oxide glucose sensors for neutral pH environments.
• This innovation facilitates in-situ glucose monitoring in diverse biological samples, expanding the applicability of non-enzymatic sensing.
• The developed sensor shows potential for point-of-care diagnostics and continuous glucose monitoring applications.