Bilisense: An affordable sensor for on-site diagnosis of jaundice and prevention of kernicterus.

Bilirubin (BR) in blood serum is elevated during jaundice (a common complication among newborns). Accessible and frequent monitoring of BR is necessary for timely diagnosis and intervention. This work developed a low-cost electrochemical sensor for point-of-care and at-home measurement of BR. The sensor measures BR based on its oxidation at a laser-induced graphene electrode. A microfluidic channel for sample wicking is embedded on the electrodes to bifurcate the blood sample into two zones to allow measurement of different BR forms (conjugated and unconjugated). One zone remains bare, while the second zone is impregnated with caffeine sodium benzoate, which acts as an accelerant to release albumin-bound BR and makes it accessible for electrochemical oxidation. The sensors demonstrate linear response in the concentration range of 100 to 500 µmolL total bilirubin (4:1 ratio of unconjugated to conjugated bilirubin) in undiluted blood serum. Physiologically relevant BR levels range from 170 µmolL (healthy concentrations) to 460 µmolL (elevated, unhealthy concentration). Recovery values at 150 and 250 µmolL are 119 % and 104 %, which fall within the 20 % error required by the United States Food and Drug Administration. This device represents the first point-of-care bilirubin-sensor capable of distinguishing between different forms of bilirubin.