Akhmad Sabarudin, Aulia Ayuning Tyas, Bagas Dwi Pamungkas, I. Gede Bhaskara Adi Pratama, Ulfa Andayani, Setyawan Purnomo Sakti
Renal failure is often detected when it has reached the last stage. The amount of cystatin C in blood serum can be used as a biomarker for early identification of renal function failure. This work reported a fast and environmentally friendly microfluidic paper-based analytical device (μPAD) to determine the amount of cystatin C in the artificial blood serum samples. Functionalized gold nanoparticles (AuNPs) were prepared by capping the surface of AuNPs with papain to form AuNPs-papain. The aggregate of functionalized AuNPs-papain and Cu2+ ion could be formed due to coordination interaction between Cu2+ ion and papain attached to AuNPs. In the presence of cystatin C, the amount of aggregate decreased because the functionalized AuNPs-papain would bind easily with cystatin C as the substrate of papain. The intensity of aggregate on μPAD was scanned using a paper scanner. The difference intensity of aggregate in the presence of cystatin C was proportional to the concentration of cystatin C in the artificial blood serum sample. The linearity range obtained by this work was 0.5-10.0?mg/L with regression of y=0.3302x+3.488 and linearity of r2=0.998. The limit of detection (LOD) and limit of quantitation (LOQ) were 0.511 (3xSD/slope) and 2.044?mg/L (12xSD/slope), respectively. The linearity range and the LOD were wide enough to detect cystatin C in normal people or people with renal diseases. © 2023 Author(s).
Department of Chemistry, Faculty of Science, Brawijaya University, Malang, 65145, Indonesia; Research Center for Advanced System and Material Technology, Brawijaya University, Malang, 65145, Indonesia; Department of Chemistry, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand; Departement of Physics, Faculty of Science, Brawijaya University, Malang, 65145, Indonesia