Impedimetric, PEDOT:PSS-based Organic ElectroChemical Sensor for Detection of Histamine for Precision Animal Agriculture

High concentrations of histamine are associated with subacute ruminal acidosis, a common disease in high-producing lactating dairy cows. Therefore, the accurate detection of low histamine levels is a strategy to monitor and diagnose ruminal acidosis in early stages. In this letter, we have developed an impedimetric histamine biosensor based on an organic semiconductor: poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). It can be utilized to detect low concentrations of histamine in a phosphate-buffered saline (PBS) buffer and McDougall's buffer solution (MDBS) with an impedimetric readout technique. With PEDOT:PSS film as the sensing medium, the device displayed a limit of detection of 0.1 μM and an impedance of ∼82 Ω at low frequencies in MDBS. The impedance is correlated with the concentration of histamine: the R2 values in the PBS (pH = 5.5 and pH = 7.4) and the MDBS (pH = 8.4) are 0.95, 0.95, and 0.99, respectively. The sensor is fabricated using large-area solution processing technology, opening the door to low-cost, high-volume commercial sensor production.