Flip-chip UVC LEDs as a light source to detect human serum albumin and bovine serum albumin

Microalbuminuria can be detected using urine protein test strips. However, this approach can only be used for qualitative analysis. Moreover, despite the high accuracy of commercial instruments for the clinical detection albumin, these devices is not suitable to be used for home detection due to their bulky size and additional labeling steps. Therefore, our study sought to develop a label-free method by five types of miniaturized detector devices (MDDs) for the detection of HSA and BSA. Using flip-chip (FC) ultraviolet-C (UV–C) light-emitting diodes (FC UVC LEDs) as a light source. The most accurate of the five tested MDDs consisted of a FC UVC LED light source, optical quartz fiber (OQF), a holder, and two quartz lenses (QL1 and QL2) with a light divergence angle of 1.8°. When detecting human serum albumin (HSA) and bovine serum albumin (BSA)at concentrations ranging from 0.01 to 4 mg/mL, the coefficients of determination (R2) of absorbance and concentration at 279 nm were 0.9969 and 0.9972, respectively, and the limits of detection (LOD) of BSA and HSA were 0.24 mg/mL and 0.25 mg/mL, respectively.