Silver nanoparticles enhanced enzyme-linked immunosorbent assay (ELISA) detection of cancer testis antigens (CTAs)

The Enzyme-Linked Immunosorbent Assay (ELISA) has been a cornerstone technique in laboratory medicine for over 55 years, relying on the specific binding of antibodies to antigens. ELISA's widespread use stems from its ability to detect low concentrations, its specificity, reproducibility, and potential for high-throughput screening. However, its sensitivity has limitations, prompting the exploration of innovative methods to improve the limit of detection (LOD). Nanoparticles provide a promising platform for enhancing ELISA sensitivity. Due to their high surface-to-volume ratio, they offer increased binding sites for capture elements and reporting tags, leading to amplified analytical signals. Recent studies have demonstrated improved sensitivity in ELISA through nanoparticle application, yielding faster detection times and enhanced sensitivities. This study investigates the potential of 50 nm citrate-capped silver nanoparticles to enhance ELISA's performance in quantifying cancer testis antigens (CTAs).

In our study, we used the Human NY-ESO-1 ELISA kit (for research purposes) to determine the concentration of CTAs in randomly selected samples from healthy (n=89) and oncological (n=80) subjects, aged 18-75. We employed 50 nm citrate-capped silver nanoparticles (AGCB50-1M, BioPure Silver Nanoparticles - bare citrate, nano-Composix, San Diego, CA, USA). ELISA reactions followed the manufacturer's instructions, and data processing aligned with the same guidelines. Absorbance (OD) measurements occurred at 450 nm, influencing nanoparticle selection. Each ELISA well contained 5 ml of nanoparticles' stock solution with specified concentrations. CTAs concentrations were derived from the standard curve through CurveExpert Basic software. Statistical analysis was performed using SPSS v. 27 software, with p-values indicating significance if <0.03. The study adhered to Helsinki Declaration principles and received ethical approval. Participants provided informed written consent.

The increased concentration values of CTAs for healthy individuals and cancer patients were determined in the case of the application of silver nanoparticles.

The usage of nanoparticles can enhance the sensitivity of the ELISA method and positively influence its specific detection limit.