Quantitative Rapid Tests for Urine Creatinine via Fenton’s Reaction and Self-Driven Microfluidic Devices

Abstract

Urine creatinine plays a pivotal role both as an indicator for kidney impairments as well as a normalizer for other urine markers to account for the variance of urine volume. Here we report a quantitative rapid test that converts urinary creatinine level into length of visual bar on a microfluidic device. Hydroxyl radicals in Fenton’s reaction are used to cleave an oligonucleotide linker designed to bind magnetic microparticle (MMPs) and polystyrene microparticles (PMPs). Due to creatinine’s inhibition of hydroxyl radicals, creatinine level is reflected by the increase of microparticle bindings. Measured through the length of PMP accumulation on the microfluidic device, we achieved a limit of detection (LOD) of 20.11 mg/dL, high tolerance to interfering factors and wide range of pH, and 0.92 concordance correlation by comparing our method to the standard method using 21 clinical urine samples, suggesting good accuracy and compatibility in clinical conditions.