An innovative and mass-sensitive quartz tuning fork (QTF) biosensor for GFAP detection: A novel approach for traumatic brain injury diagnosis

The early diagnosis and management of traumatic brain injury (TBI) are dependent upon the early and precise detection of glial fibrillary acidic protein (GFAP). In this investigation, a novel biosensor based on quartz tuning forks (QTF) was introduced and functionalized with 11-mercaptoundecanoic acid (11-MUA). This biosensor is designed to facilitate the highly sensitive and selective detection of GFAP in human serum. In contrast to conventional neuroimaging methods, which are resource-intensive and frequently inaccessible in emergency situations, this innovative biosensor offers a portable, cost-effective, and efficient alternative for rapid GFAP measurement. The detection range of the system is 0.05 fg mL−1 to 25 fg mL−1. The Atomic Force Microscopy (AFM) was utilized to visualize the morphology of the QTF surface during the immobilization steps of the sensor. The developed biosensor presented advantages such as ability to determine GFAP concentrations at femtogram level, reproducibility and repeatability (standard deviation: ±0.0935966 Hz, and coefficient of variation: 7.91 %). This study highlights a significant progression in biosensing technology, providing an exceptionally sensitive and scalable platform for diagnosing neurological disorders, with potential uses in point-of-care environments. © 2025 The Authors