Abstract

Tablet-based assays are particularly promising because of their portability and long shelf life; however, nearly all reported formats rely on optical readouts that are slow, depend on external readers, and are prone to color interference. Electrochemical biosensors provide a faster and more sensitive alternative but often require enzyme immobilization, a multi-step process that can reduce activity, complicate fabrication, and limit scalability and reproducibility.
In response to these challenges, this thesis introduces an electrochemical tablet (eTab) platform in which all reagents are encapsulated within a pullulan matrix and released upon dissolution to produce a ready-to-use solution. As a proof of concept, glucose and lactate eTabs were developed, exhibiting linear detection ranges of 0–15 mM and 0–4 mM, with detection limits of 0.11 and 0.14 mM, respectively, covering their physiological concentrations in plasma. The eTabs demonstrated excellent reproducibility (RSD < 6%) and they maintained their initial performance with less than 10% signal deviation after 30 days of storage at room temperature, whereas comparable solution-phase reagents showed progressively increasing signal drift. Both assays achieved over 90% recoveries in human plasma and showed negligible interference from common interferents.
By combining the durability of tablet-based assays with the analytical performance of electrochemical sensing, this work establishes a simple, stable, and reproducible platform for next-generation POC diagnostics, with potential applications in biomedical testing, environmental monitoring, and food-safety analysis.