Smartphone‐Based Portable Colorimetric Biosensor for Chronic Kidney Disease (CKD) Biomarker Detection Using Gold Nanoparticles

ABSTRACT

Chronic kidney disease (CKD) is a serious disorder that affects 10% to 15% of the world population. CKD can be life‐threatening if not treated on time, leading to kidney replacement and even death; therefore, detection of CKD is very important. Creatinine (Cr) and albumin (Alb) are two critical biomarkers; their concentrations are crucial for assessing kidney health. In the present work, we have synthesized two nanoparticles (NPs), spherical gold nanoparticle anion (SGNA) and spherical gold nanoparticle cation (SGNC), by using a chemical reduction procedure. SGNA NPs were used for sensing of Cr and SGNC NPs have been employed for the detection of Alb. They showed a good response in the relationship with different concentrations of Cr and Alb, respectively. Addition of Cr to SGNA causes aggregation due to electrostatic interactions between SGNA and Cr, resulting in a color change from ruby red to blue, and a shift in the absorption maximum ( λ _max ) peak from 518 to 648 nm. A change in color and wavelength is related to Cr concentration, ranging from 0.068 to 0.0826 mg/dL. The limit of detection (LOD) for the Cr sensing by SGNA was found to be 0.001 mg/dL. Similarly, addition of Alb to SGNC causes aggregation, resulting in a color change from ruby red to blue; the absorption maximum peak ( λ _max ) shifts from 522 to 577 nm. Change in color and shift in the absorption wavelength are also related to Alb concentration, ranging from 2.5 to 35.0 mg/dL. The detection limit for the Alb sensing by SGNC was 2.5 mg/dL.