Flat-chip microanalytical enzyme sensor for salivary amylase activity.

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Enzyme Biosensors

Background:

• Salivary alpha-amylase activity is a valuable biomarker for assessing sympathetic nervous system function.
• Existing methods for salivary amylase measurement lack the miniaturization required for wearable applications.
• Development of sensitive and compact biosensors is crucial for continuous physiological monitoring.

Purpose of the Study:

• To design and fabricate a novel flat-chip microanalytical enzyme sensor for salivary amylase activity.
• To miniaturize the biosensor using Micro-Electro-Mechanical Systems (MEMS) technology for wearable analytical systems.
• To achieve high sensitivity for accurate salivary amylase activity measurement.

Main Methods:

• Incorporated a pre-column and a flat-enzyme electrode within a miniaturized flow cell.
• Immobilized two enzymatic membranes (maltose phosphorylase and glucose oxidase-peroxidase) on a planar surface for miniaturization.
• Optimized sensor parameters including enzyme immobilization, solution dropping volume, and flow rate.

Main Results:

• Successfully fabricated a flat-chip sensor with a flow cell comparable in size to a C battery.
• Developed an analytical system capable of measuring amylase activity from 0-190 kU/l with a high correlation coefficient (R² = 0.97).
• Utilized a minimal sample volume of 50 microliters.

Conclusions:

• The developed flat-chip sensor demonstrates high sensitivity and miniaturization potential for wearable analytical systems.
• This technology enables continuous monitoring of salivary amylase activity.
• The sensor design holds promise for non-invasive, real-time assessment of sympathetic nervous system function.