Smartphone based non-invasive salivary glucose biosensor

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Point-of-Care Diagnostics

Background:

• Diabetes mellitus is a global health concern requiring accessible diagnostic tools.
• Current blood glucose monitoring methods can be invasive and costly.
• Saliva offers a promising non-invasive alternative for glucose level assessment.

Purpose of the Study:

• To develop a non-invasive optical glucose biosensor utilizing saliva and smartphone technology.
• To fabricate a cost-effective and user-friendly device for glucose detection.
• To establish the clinical utility and correlation of salivary glucose with blood glucose levels.

Main Methods:

• Immobilization of glucose oxidase enzyme and a pH-responsive dye on a filter paper strip.
• Colorimetric detection of glucose in saliva using RGB profiling via a smartphone camera.
• Calibration using spiked saliva samples and clinical validation on healthy, prediabetic, and diabetic subjects.

Main Results:

• The biosensor demonstrated good sensitivity, low interference, and a rapid response time of 20 seconds.
• A linear detection range of 50-540 mg/dL was achieved with a sensitivity of 0.0012 pixels sec⁻¹/mg dL⁻¹ and LOD of 24.6 mg/dL.
• Significant correlations were found between salivary and blood glucose levels (0.44 healthy, 0.64 prediabetic, 0.94 diabetic).

Conclusions:

• The developed optical biosensor offers a viable, non-invasive method for glucose monitoring using saliva and a smartphone.
• This technology has the potential for mass diabetes diagnosis, particularly in areas with limited healthcare access.
• The low cost and ease of use make it suitable for widespread adoption and self-monitoring.