A System-On-Chip Assay for Bilirubin Levels Measurement in Whole Blood Using Photodegradation Kinetics

Bilirubin is clinically confirmed as a biomarker for liver health and is used to assess the prognosis of cirrhosis. Optical and chemical methods have long been utilized for blood bilirubin biosensing. While spectrophotometric techniques provide more accurate results, measurements may not be practical due to the instrument complexity and space requirements as they require volumetric equipment and reagents are sometimes preprocessed. These steps are rather time-consuming and can be detrimental in cases of emergency. Several studies have attempted and used the dual-wavelength approach to overcome these limitations; however, although this creates the possibility of Point-of-Care (PoC) and fast testing, it suffers from reduced accuracy. This paper investigated the feasibility of PoC bilirubin monitoring by photodegradation kinetics using a system-on-chip (SoC). Porcine blood was used, and bilirubin levels were kept within the pathophysiological ranges projected from healthy individuals (<1.2 mg/dL) and cirrhotic patients (up to 50 mg/dL). Our findings suggest that bilirubin can be measured with high sensitivity in blood using bilirubin degradation profiles. This technique can be incorporated with the dual-wavelength approach to increase the reliability and accuracy of point-of-care testing for bilirubin levels, primarily for neonatal hyperbilirubinemia and cirrhotic adults.