Ultrasensitive biosensor for near femtogram-level detection of interleukin-1 beta in saliva

Periodontitis, whose early symptoms are subtle and frequently ignored, can ultimately lead to permanent harm to the teeth and their supporting tissues. Therefore, a prompt and precise diagnosis, coupled with progression monitoring, is crucial for clinical treatment. Organic electrochemical transistors (OECT) based sensors offer high sensitivity, low driving voltage, and biocompatibility, capable of transducing biochemical binding events into electrical signals with high signal-to-noise ratios. Herein, a vertical OECT (vOECT)-based electrochemical immunosensor is developed for detecting interleukin-1 beta (IL-1β), a biomarker strongly associated with periodontitis present in saliva. This biosensor exhibits high sensitivity (110.28 μA dec^-1) and a broad linear detection range (10 fg/mL to 5 ng/mL) for IL-1β in both PBS solution and artificial saliva. Notably, this biosensor successfully distinguishes healthy rats from those with periodontitis using untreated rat saliva samples, demonstrating high selectivity and sensitivity, exhibiting an area under the receiver operating characteristic curve (AUC) of 0.91. This work demonstrates considerable potential to develop an auxiliary, non-invasive point-of-care diagnostic tool for periodontitis, which could facilitate disease progression prediction, treatment decision guidance, and prognosis evaluation.