Paper-based colorimetric microfluidic device for visual detection of glucose coupling different-shaped gold nanostructures with cerium oxide nanozyme

Abstract

Diabetes mellitus is a rapidly spreading chronic disease whose prevalence has increased by over 50 % in the past decade, owing to current trends in lifestyle, food choices, and increasing obesity rate. Therefore, there is a need to develop cheap and user-friendly glucose monitoring detection methods, especially in low-income countries. In this study, we explored different gold nanoparticles (AuNP) in combination with cerium oxide (CeO2) to assess the effects of nanoparticle morphological structure on their enzyme-mimicking properties. Our results showed that gold nanorods (AuNR) displayed the highest enzyme-mimicking properties compared to other AuNPs like gold nanowires, nanospheres, nanourchins, and microrods. Subsequently, we developed a nanozyme paper microchip using CeO2–AuNR bimetallic nanocomposite as peroxidase mimics that allow for visual identification towards glucose detection. The paper microchip was developed by simple thermal printing over filter paper that gave a visual response through a colourimetric signal. An intense blue-coloured response directly proportional to glucose concentration was observed on the paper sensor, displaying high sensitivity, sensitivity, and reproducibility even in clinical samples, including serum and urine. The sensor demonstrated a linear detection range of 0.5 to 500 mg/dL, with a limit of detection (LOD) of 0.65 mg/dL and showed excellent recovery rates (93 % –98.27 % in serum and 91.84 % – 109.5 % in urine), indicating its potential for real-world applications. Thus, the paper sensor developed in this work is a potential blueprint for developing next-generation simple, portable, and user-friendly nanozyme-based point-of-care (POC) biosensors for glucose monitoring.