Thin-Film Biosensors in Public Health: Review for E. coli Detection

In response to escalating concerns regarding food hygiene, there is an urgent demand for expedited and dependable methods for bacterial detection. Escherichia coli (E. coli) stands as a pivotal indicator organism, delineating potential fecal contamination and associated health hazards. This scholarly inquiry investigates the viability of employing thin-film biosensors for swift and discerning E. coli detection, thereby making substantial strides in safeguarding public health. This investigation highlights the underlying principles governing these biosensors, accentuating the pivotal role of functionalization in facilitating precise capture and detection. Diverse materials and deposition techniques employed in thin film fabrication are scrutinized, elucidating their respective merits and demerits. Moreover, this study showcases two specific instances elucidating the multifarious applications of thin-film biosensors in bacterial detection. The first case delineates a surface-enhanced Raman scattering (SERS)-based nano biosensor chip adept at single-cell E. coli detection, capitalizing on signal amplification through targeted capture facilitated by bacteriophages. The second instance delineates a cost-efficient strategy leveraging a zinc oxide (ZnO) thin film functionalized with immobilized antibodies for E. coli detection. The exposition of both highly sensitive and economical options underscores the adaptability of thin-film biosensors in combating bacterial perils. Subsequent research endeavors should pivot towards augmenting sensitivity, specificity, and multiplexing capabilities to ensure comprehensive bacterial detection across diverse environments.