A paper strip based non-invasive glucose biosensor for salivary analysis

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Biosensors

Background:

• Direct glucose determination in biological fluids is crucial for diabetes management.
• Current methods for blood glucose monitoring can be invasive and inconvenient.
• Saliva offers a promising alternative matrix for non-invasive glucose monitoring.

Purpose of the Study:

• To develop and validate an optical biosensor for the direct determination of glucose in human saliva.
• To assess the correlation between salivary glucose levels and blood glucose levels in healthy and diabetic individuals.
• To establish the feasibility of using RGB profiling for quantitative glucose analysis in saliva.

Main Methods:

• Immobilization of glucose oxidase enzyme and a color pH indicator on a filter paper strip.
• Colorimetric detection of glucose concentration via RGB profiling using an office scanner and image processing software (GIMP).
• Standardization of the biosensor with synthetic glucose samples and subsequent testing with human saliva and blood glucose measurements using a glucometer.

Main Results:

• The optical biosensor demonstrated a glucose detection range of 9-1350 mg/dL with a response time of 45 seconds and a limit of detection (LOD) of 22.2 mg/dL.
• A significant correlation was observed between salivary and blood glucose levels: r=0.64 in healthy individuals and r=0.95 in diabetic patients.
• The RGB profiling method proved effective for quantifying glucose concentrations based on color changes in the biosensor.

Conclusions:

• The developed optical biosensor is a viable tool for direct and non-invasive salivary glucose determination.
• Salivary glucose analysis, particularly using this RGB profiling method, shows strong potential for monitoring glucose levels, especially in diabetic individuals.
• This approach validates the importance of salivary analysis as a complementary method for glucose monitoring.