@article{AHAMED2025116392,

title = {Elliptical Electrode Designs in Quartz Crystal Microbalances: Enhancing Sensitivity in Liquid Biosensing Applications},

author = {Afri Ahamed and Chien Wei Ooi and Hui Jean Lim and N. Ramakrishnan and Tridib Saha},

url = {https://www.sciencedirect.com/science/article/pii/S0924424725001980},

doi = {https://doi.org/10.1016/j.sna.2025.116392},

issn = {0924-4247},

year  = {2025},

date = {2025-03-03},

urldate = {2025-01-01},

journal = {Sensors and Actuators A: Physical},

pages = {116392},

abstract = {The demand for highly sensitive and versatile sensors is rapidly growing in biomedical applications, where specific, sensitive, and rapid detection are essential. Quartz crystal microbalance (QCM) is a popular analytical tool for such applications due to its high sensitivity and real-time monitoring capabilities. However, conventional QCM-based biosensing assays often suffer from poor sensitivity and high sample consumption, limiting their practicality. This study introduces a modified electrode design and a single droplet-based assay to enhance QCM-based bio-detection. Through extensive experiments, including contact angle analysis, damping, and viscosity measurements, we identified an optimal elliptical electrode design for single droplet-based liquid sensing. Using QCM crystals coated with molecularly imprinted polydopamine (MIPDA) sensing films containing recognition sites for detecting pepsin as a model protein, we demonstrate that QCM crystals with elliptical electrodes exhibit up to 10 times higher sensitivity than the industry-standard 1-inch circular QCM crystal. Additionally, the optimized QCM crystals showed linear sensitivity over a wider volume range, providing consistent detection at 250Hz/μl compared to the circular crystal's narrower range at 50Hz/μl. These findings establish a foundation for next-generation QCM platforms with superior sensitivity, reduced sample requirements, and broader adaptability, paving the way for advancements in biomedical diagnostics and environmental monitoring.},

keywords = {Deionised Water (DI Water), Elliptical Electrodes, Liquid Droplet Detection, openQCM Q-1, Protein Sensing, Quartz Crystal Microbalance (QCM)},

pubstate = {published},

tppubtype = {article}

}