A Spicy Recipe for At-Home Diagnostics: A Smart Salivary Edible Sensor for The Point-of-Care Diagnosis of Jaundice

Introduction: Even though significant advances have been made, there is still a lack of reliable sensors capable of non-invasively monitoring bilirubin and diagnosing jaundice as the most common neonatal disease, particularly at the point-of-care (POC) where blood sampling from infants is accompanied by serious challenges/concerns. Aiming to address this utmost important necessity, we herein introduce a smart, easy-to-fabricate/use sensing bioplatform that enables the non-invasive optical monitoring of bilirubin in saliva at the POC.

Methods: Herein, the high sensing capability of curcumin as a natural edible pigment is demonstrated in paper-based assays for the optical monitoring of bilirubin in saliva. To measure and quantify the fluorescence signals of the developed sensing bioplatform, we fabricated an Internet of Things (IoT)-enabled hand-held optoelectronic reader, enabling the smart POC diagnosis of jaundice and its therapeutic monitoring by clinicians remotely.

Results: The sensing mechanism behind the selective response of our developed sensor for bilirubin is based on bilirubin photoisomerization under blue light exposure, resulting in the selective recovery of the bilirubin-induced quenched fluorescence of curcumin. The sensor exhibited a linear range (0.5-20.5 μM) with r²=0.984, LOD=0.2 μM, and intra- and inter-day RSDs between 1.8% and 4.9%. The clinical analysis of the saliva of eleven jaundiced infants using our developed sensor strongly proved that it is amenable to be widely exploited in POC applications for bilirubin monitoring as there are excellent correlations (R=0.994, and R=0.99) between its results and those of reference methods for saliva and blood. We also recommended an IoT-based model capable of meeting the Healthcare 4.0 prerequisites.

Conclusions: The developed smart salivary sensor is believed to be highly promising for exploitation in the ultra-low-cost, non-toxic, easy, and non-invasive smart diagnosis and therapeutic monitoring of jaundice, hepatitis, and other bilirubin-induced neurologic diseases at the POC and in patient/home-centric healthcare systems, since it meets all of WHO’s REASSURED criteria for ideal diagnostic devices.