Improved immunoassay for Insulin-like Growth Factor 1 detection by aminated silica nanoparticle in ELISA.

• Abdominal aortic aneurysm (AAA) is the vascular disease forming when aorta swells. • Insulin-like Growth Factor 1 (IGF1) is the circulating biomarker for AAA detected. • Improved ELISA through the aminated silica nanoparticle (SiO 2) mediation. • 400pM of IGF1 detected on amine-SiO 2 modified ELISA & 12.5 nM in conventional ELISA. • Detected in the mixture of IGF1 and relevant proteins (IGF2 and IGFBP3). Abdominal aortic aneurysm (AAA) is the vascular disease forming when aorta in the abdomen swells. AAA with the size of 5.5 and above has possibility to rupture and leads a death. Insulin-like Growth Factor 1 (IGF1) is the circulating biomarker for AAA diagnosis, in this study IGF1 was detected by the improved Enzyme linked Immunoassay (ELISA). The conventional ELISA necessitates the improvement due to the lesser sensitivity than modern sensors. Higher biomolecular immobilization is one of the wise ways to enhance the sensitivity. This study was aimed to capture a higher number of IGF1 on ELISA surface through the aminated silica (SiO 2) nanoparticle with the size measured to be 80−100 nm. On the amine-SiO 2 modified surface, Glutaraldehyde (GLU) complexed IGF1 was chemically bonded. It was found that 400 pM of IGF1 detected on amine-SiO 2 modified ELISA, whereas the conventional ELISA without nanoparticle mediation shows the limit of detection as 12.5 nM with ∼30 times lower detection. The selectivity experiment was carried out with the mixture of IGF1 and relevant proteins (IGF2 and IGFBP3), and it was noticed that anti-IGF1 selectively detected IGF1. This nanoparticle-mediated surface immobilization captured a higher rate of antigen on a larger surface created for high-performance detection. [ABSTRACT FROM AUTHOR]