Development of a Low-Cost Portable QCM Biosensing System for On-Site Diagnostics

This paper presents the design and testing of a portable, low-cost Quartz Crystal Microbalance (QCM) biosensor measurement device. The device integrates a QCM with Resistance monitoring (QCM-R) measurement system and a microfluidic system, managed jointly by a computer via a Python application. The QCM-R measurement system comprises front-end electronics and a digital architecture based on Field-Programmable Gate Array (FPGA) for accurate oscillation frequency measurement. The microfluidic system includes four piezoelectric micropumps interfaced with a dedicated measurement chamber, ensuring precise fluid flow control and delivery to the QCM sensor surface. The system is operated in feedback with a microcontroller through a flow sensor, enabling real-time adjustments and constant fluid flow rates. The measurement chamber, designed for both dynamic and static measurements, was realized using Masked Stereolitography (MSLA) techniques and low-cost PVA based resin. The device performance was evaluated through microfluidic system testing and measurement chamber performance testing. The results demonstrate the device potential for advanced biosensing applications, facilitating onsite testing, rapid results, and potential for mass deployment in resource-limited settings.