A novel assay format as an alternative to ELISA: MINA test for biotin

Abstract

A novel abiotic assay based on biotin‐specific fluorescent molecularly imprinted polymer nanoparticles (nanoMIPs) which acted as both reporter probes and binding agents, was developed. This is a first report of an assay which, unlike ELISA, required no washing steps or addition of enzyme substrates, making it more user‐friendly. The components of the molecularly imprinted polymer nanoparticles assay (MINA) were assembled in microtiter plates fitted with magnetic inserts. The fluorescent nanoMIPs were bound to biotin‐conjugated magnetic particles, which were attracted to the inserts. The addition of free biotin caused a displacement of the fluorescent nanoMIPs into solution, generating a signal proportional to the concentration of biotin. The nanoMIPs had a dissociation constant (Kd) of 14 nM, allowing the assay to detect biotin at nano‐molar concentrations. The pre‐assembled assay only required the addition of the sample and measurement of the fluorescence, and it functioned well after six weeks of storage without refrigeration. The assay did not show the susceptibility to several compounds which are known to interfere with avidin and streptavidin‐based assays, such as mercaptoethanol and sugars. The protocols optimized in this work could be used to develop the abiotic assays for any other compound of interest.