Comparative Study of the Developed Chemiluminescent, ELISA and SPR Immunoassay Formats for the Highly Sensitive Detection of Human Albumin

Chemiluminescent enzyme immunoassay (CLEIA), surface plasmon resonance (SPR) immunoassay and enzyme- linked immunosorbent assay (ELISA) were developed for the highly sensitive detection of human albumin (HA). The bioanalytical procedure, involving the surface modification and antibody immobilization, was the same for all immunoassay formats. The bioanalytical platforms, i.e. microtiter plates (MTP) and SPR gold chips, were initially functionalized with 3-aminopropyltriethoxysilane and then crosslinked to anti-HA antibodies using 1-ethyl-3-[3- dimethylaminopropyl] carbodiimide hydrochloride and sulfo-N-hydroxysuccinimide. The developed HA immunoassay formats were compared on the basis of their analytical performance. CLEIA was found to be the best format for HA detection as it had the highest analytical sensitivity with lowest limit of detection and widest dynamic range. The analytical sensitivity of various immunoassay formats were in the decreasing order of CLEIA > ELISA > SPR. The developed CLEIA for HA detection was 6-fold more sensitive than the widely used commercially-available ELISA. The anti-HA antibody bound MTPs, stored at 4 °C in 0.1 M PBS, pH 7.4, were stable for up to 4 weeks, and can be effectively used for the rapid detection of HA in just 2.5 h.