GlowSense: Development of a Smartphone Application for Monitoring Bacterial Vaginosis Using a Sanitary Pad Insert Embedded with Fluorescein and Nitrogen-Doped Carbon Quantum Dots for Fluorescence-Based Sensing
Chemistry- Grade:
- 12
- Teacher:
- Alfred Santos
Bacterial vaginosis (BV) is one of the most common vaginal infections women suffer that goes unnoticed. Failure to diagnose Bacterial Vaginosis may increase the risk of other health issues. To address this problem, my partner and I developed an innovative smartphone app–based solution with a fluorescence sensing pad to monitor the growth of bacterial vaginosis. This project was conducted using the following methods. We developed the N-doped carbon and fluorescein dots by dissolving citric acid and urea in distilled water and microwaving it at 700–800 W for 3–5 minutes until it turned orange-brown, then diluting it with water, filtering it and checking the glow under a UV lamp. The brightness was adjusted by adding more N-CDs if the solution looked too green or more fluorescein if it looked too blue while keeping the pH around 7.0. A fluorescein stock was made by dissolving 0.1 g in 1000 mL water, and the 50 mL dual-emitter biosensor was prepared by mixing N-CD stock, fluorescein, and water and stored in an amber bottle at 4 °C. To make the biodegradable pad insert, sodium alginate was dissolved in water combined with agar-agar powder and glycerin. It was heated until thick, then after slightly cooling the solution 10 mL of the biosensor was poured into a silicone mold. To test the pad, buffers from pH 4.0 to 6.0 were added, left for 2 minutes, and imaged in a BlueGel chamber where low pH showed dim green-blue emission and higher pH became bright green. For the GlowSense app, we used MIT App Inventor. Pictures of the pads at different pH levels calculated the Blue-Green Ratio and showed brighter green fluorescence as pH increased. The results indicate that the colorimetric sensor can reliably signal BV risk through distinct color changes as vaginal pH increases. The G/B fluorescence ratio rose consistently from pH 4.0 to 6.0, confirming sensitivity to elevated pH. A strong linear correlation (R² = 0.94) supports accurate pH prediction based on color response.