Smartphone-assisted immunosensing of cancer biomarkers in human biofluids using poly (methyl methacrylate) decorated by triangular silver nanoparticles

Abstract

This system utilizes an innovative platform consisting of a poly (methyl methacrylate) (PMMA) plate adorned with triangular silver nanoparticles, enabling the sensitive and specific detection of prostate-specific antigen (PSA), carcinoembryonic antigen (CEA), and cancer antigen 15–3 (CA 15.3). To achieve this, the PMMA polymer microarrays were precisely cut using a laser cutting machine to create an optimized number of micro-arrays. These designed wells were embellished with triangular silver nanoparticles (TA-AgNPs) featuring prism morphology. The antigens could be easily detected based on antigen–antibody-induced aggregation of TA-AgNPs and resulting in a visible color change due to the alteration of surface plasmon resonance properties. Consequently, utilizing the immunocomplex of antigen–antibody in the presence of the optical probe (TA-AgNPrs) and a portable photochemical sensor, candidate cancer biomarkers (PSA, CEA, and CA 15.3) were successfully identified with linear ranges of 1–60, 1–75, and 1–125 µg/mL, respectively. By employing digital image analysis using a smartphone, we achieved a highly favorable low limit of quantification of 1 µg/mL for PSA, CEA, and CA 15.3 as biomarkers for prostate, colon, and breast cancer, respectively. This groundbreaking research introduces a pioneering digital image-based colorimetry immunoassay, the first of its kind in the field, providing a transformative approach to the early-stage diagnosis of various cancer biomarkers through a single opto-device. To the best of our knowledge, no smartphone ambient light sensor has yet been specifically designed to identify PSA, CEA, and CA 15.3 proteins as cancer biomarkers. Therefore, a sensory micro-array was developed to open new possibilities for the rapid and simple colorimetric identification of PSA, CEA, and CA 15.3 antigens in real samples, offering a sensitive and specific monitoring strategy for these biomarkers through colorimetry.