Poster W7 - Balancing flavor and health: A novel vanillin sensor for precise dietary intake analysis

Introduction: Saliva has emerged as a vital biofluid for non-invasive diagnostics, offering an alternative to traditional blood sampling. Traditional methods of saliva collection can be uncomfortable, requiring individuals to produce large volumes of saliva. Our study introduces a novel point-of-care device for easy, comfortable saliva collection and analysis. Vanillin, a key focus of this study, is a prevalent flavoring compound used extensively in the food industry. Despite its general safety as recognized by regulatory bodies like the FDA and FEMA, excessive intake of vanillin can lead to significant health implications, necessitating its monitoring in human diets.

Materials and

Methods: The device shell is designed by Fusion 360 (Autodesk Inc.) and fabricated by a Fused deposition modelling (FDM) 3D-printer (Adventurer 4, Flashforge Technology Co.) with poly(lactic acid) resin. Laser-Induced Graphene (LIG) fabricated by 30 W CO2 laser engraver (VLS 2.30, Universal Laser System) was used as working electrode with Nafion modification. A LIG reference electrode was prepared by drop-casting Ag/AgCl ink on LIG, leaving the counter electrode blank. Testing methodologies included cycle voltammetry and differential pulse voltammetry with an electrochemical working station (CHI760E, CH Instruments, Inc.).

Results, Conclusions, and Discussions:

Results: The electrochemical sensors embedded within our microfluidic device successfully detected vanillin with a dynamic range of 2.5 μM to 30 μM in saliva. This range covers the physiologically relevant concentrations of vanillin in saliva. The system requires only 200 μL of saliva and achieves full functionality in less than two minutes, demonstrating its efficiency in rapid saliva sampling and analysis.

Conclusions: Our findings confirm that this point-of-care saliva collection device not only facilitates easier and more comfortable saliva collection but also effectively measures vanillin levels, potentially indicating overconsumption. This capability is crucial, given the adverse health effects associated with high vanillin intake.
Discussions: This device represents a significant advancement in the field of non-invasive diagnostics. This system not only enhances patient comfort during saliva collection but also simplifies the process of monitoring substances like vanillin that have health implications. Future studies could expand the range of detectable analytes and further validate the device's clinical utility in real-world scenarios.

Acknowledgements (Optional): Haozheng Ma would like to acknowledge the Viterbi Graduate School Fellowship.