Using Blue Mini-LEDs as a Light Source Designed a Miniaturized Optomechanical Device for the Detection of Direct Bilirubin

This study developed a miniaturized optomechanical device (MOD) for the feasibility study of direct bilirubin in urine using high-collimation blue mini-light-emitting diodes (Mini-LEDs) as the light source. The constructed MOD used optical spectroscopy to analyze different concentrations of direct bilirubin using the absorbance spectrum to achieve a noninvasive method for detection. The experimental results showed that between the absorbance and different concentrations of direct bilirubin at the blue Mini-LEDs central wavelength (462 nm) was the optimum fitting wavelength; in the direct bilirubin concentration range from 0.855 to 17.1 μmol/L, the coefficient of determination (R2) was 0.9999, the limit of detection (LOD) of 0.171 μmol/L, and the limit of quantitation (LOQ) of 0.570 μmol/L. Therefore, we propose using blue Mini-LEDs as a light source to design a MOD to replace the invasive blood sampling method with a spectroscopic detection of direct bilirubin concentration corresponding to absorbance.