Detection of NaCl Ions and TNF-𝜶 Cytokines using Pyroelectric Effect in Liquid-Silicon Heterostructures

The change of electric properties at a liquid-solid interface due to solution concentration variation has the potential to contribute toward the design of a concentration sensor. This study investigates the pyroelectric and photoelectric properties at a liquid-semiconductor heterojunction for NaCl ion and TNF- 𝛼 cytokine detection. The concentration sensor is constructed by utilizing the LED-triggered pyroelectric and photoelectric effects. Two experimental stages involve NaCl solution characterization using bare n-type silicon and TNF-𝛼 cytokine solution detection using aptamer-functionalized silicon. The collected electric current responses aim to establish the determination of solution concentrations down to nanomolar for NaCl (aq.) and nanomolar to femtomolar for TNF-𝛼. The research methodology encompasses detailed materials and methods, including circuit designs and key component selections for the sensor prototype. Results reveal distinct electric current response levels correlating with solution concentrations, providing a foundation for the biosensor’s efficacy. The biosensor prototype is encapsulated in a 3D-printed casing for accessibility. It demonstrates an integration of diverse components and shows promising results of detecting NaCl (aq.) concentration down to micromolar and the potential of pushing the range down to nanomolar. The study also highlights the possibilities for future investigations, particularly in the systematic variation of the response measurement at the cytokine-aptamer interface and the refinement of the device construction.