An integrated microfluidic system for the determination of microalbuminuria by measuring the albumin-to-creatinine ratio

Abstract

This study presents an integrated microfluidic system for the determination of microalbuminuria (MAU) through the measurements of the albumin-to-creatinine ratios in patients' urinary samples. Albumin concentrations are determined based on a non-immunological dye binding assay in which the dyes react specifically with albumin to undergo a strong fluorescence enhancement. Creatinine concentrations are determined based on the Jaffé reaction in which the reagents react specifically with creatinine to form orange-red colored complexes. Two calibration curves for determining the concentrations of urinary albumin and creatinine are constructed with assay ranges of 5-220 and 1-100 mg/l, respectively. Using this system to determine the ACRs of collected clinical urine samples, statistical tools including Bland-Altman bias plot and Passing-Bablok regression analysis show that the results obtained by the proposed microfluidic system are in good agreement with those obtained by conventional methods. This simple, automatic, inexpensive, and microchip-based platform demonstrates a promising alternative to the conventional assays for determining MAU and may be suited for clinical applications.

Gradient Waveguide Thickness Guided-Mode Resonance Biosensor

“…Urine albumin and creatinine, which are commonly used biomarkers of chronic kidney disease (CKD) [ 34 ], were used to demonstrate the effectiveness of the proposed GWT-GMR sensor in practical biosensing applications. In this study, a two-channel microfluidic chip with the embedded GWT-GMR sensor (0.72 × 4 mm 2 ) shown in Figure 1 c was used to measure either albumin or creatinine concentration levels.…”

Urine analysis in microfluidic devices

“…63,64 Recently, these microfluidic devices and systems have been extensively used for urine analysis. 65,66 It is envisioned that these microfluidic devices and systems may provide a fast and accurate urine analysis with an inexpensive per unit cost. Most importantly, point-of-care (POC) devices and systems may be feasible for urine analysis if these miniature systems can be mass-produced in the near future.…”

Label-Free Protein Detection by Micro-Acoustic Biosensor Coupled with Electrical Field Sorting. Theoretical Study in Urine Models

“…[ 17 , 18 , 19 ]. Multiple methods and devices, from dipsticks to sophisticated microfluidic platforms based on chip electrophoresis, colorimetric optical detection, immunoassays and other techniques have been developed for the POC testing of microalbuminuria (urine concentration 30–300 mg/L) and macroalbuminuria (concentration more than 300 mg/L) [ 18 , 19 , 20 , 21 , 22 ].…”

“…[17][18][19]. Multiple methods and devices, from dipsticks to sophisticated microfluidic platforms based on chip electrophoresis, colorimetric optical detection, immunoassays and other techniques have been developed for the POC testing of microalbuminuria (urine concentration 30-300 mg/L) and macroalbuminuria (concentration more than 300 mg/L) [18][19][20][21][22]. Some of the conventional biochemical methods for urine analysis are sensitive to all plasma proteins, not only albumin and in routine diagnostics the term albuminuria is often used synonymously for proteinuria, which is not always correct because eleveted levels of other proteins, often with minor concentrations, have separate clinical significance.…”