Miniaturized Conductometric Biosensor for Rapid Detection of TNF‐ <i>α</i> in Saliva

Tumor necrosis factor‐ α (TNF‐ α ) has emerged as a critical biomarker for insulin resistance and diabetic complications, offering an alternative avenue for diabetes management beyond conventional glucose monitoring. Current methods for detecting TNF‐ α are constrained by their complexity and lack of adaptability for home‐based use. We present a novel conductometric sensor engineered for highly sensitive, selective, and rapid detection (&lt;2 min) of TNF‐ α in saliva. Developed through surface modification of high‐resistivity silicon wafers, the sensor achieves quantification of TNF‐ α in the femtomolar range with the limit of detection as low as 10 fM which is 100× times lower than that of critical concentration of TNF‐ α in saliva and demonstrates robust performance under varying pH conditions. The ultrahigh sensitivity for TNF‐ α demonstrates the capability for effective prescreening method of diabetes and the demonstration of robust linear sensor response between the clinically relevant salivary TNF‐ α levels illustrates its use for practical diabetes monitoring. Leveraging a Bluetooth microcontroller, the sensor integrates wireless data transmission to a smartphone, enabling rapid and user‐friendly monitoring. This technology represents a significant advancement in TNF‐ α detection, offering a holistic approach to track disease progression and complications, with the potential to transform the early identification and monitoring of diabetic conditions.