Highly selective and sensitive molecularly imprinting electrochemical sensing platform for bilirubin detection in saliva

In this study, molecular imprinting polymer (MIP) was used to develop selective active sites for low-cost and easy-to-build bilirubin (BR) detection because BR is known as an indicator of liver function. When the liver does not excrete BR properly, it causes jaundice, which is associated with liver diseases, especially in infants. High levels of BR can cause serious brain and spinal cord damage. Therefore, the identification and measurement of BR is important. In this study, the amount of BR in saliva was determined for the first time, which is non-invasive and cost-effective. Multi-walled carbon nanotubes (MWCNTs) were used for electrode modification before electropolymerization and MIP electrode preparation. o-phenylenediamine (OPD) was electropolymerized in the presence and absence of BR. The modified electrodes were characterized using different techniques. The electrochemical sensor exhibited an excellent selectivity and sensitivity, notably 1.05 µA fM−1. Moreover, the proposed sensor showed a wide linear range (12.08 fM to 91.81 fM) with a low detection limit of 7.80 fM. Moreover, the MIP electrode demonstrated acceptable operational stability (5% of signal loss over 10 days). After a deep characterization of the sensing platform, the MIP-modified electrode was utilized for the selective detection of BR in the saliva and serum of infants.