Fe-TAML encapsulated MSN as Biomimic Peroxidase for picomole detection of proteins

Abstract

Detection of biomolecules at very low concentrations is extremely important for early detection of life threatening diseases such as cancer. Standard ELISA assays using the antibody conjugated enzyme horse radish peroxidase (HRP) is routinely used for detection of biomolecules. The role is HRP is to amplify the signal which lowers detection limit. Development of HRP mimics which show more activity that the natural enzyme can bring down the detection limits. We have synthesized mesoporous silica nanoparticles (MSN) containing thousands of small molecule synthetic HRP mimic Fe-TAML that are encapsulated inside their pores. We show that this Fe-TAML encapsulated MSN have kcat values that are 1000-folds higher than the native HRP enzume. Using this nanoparticle, we have developed a highly sensitive and selective linear amplification scheme by using enzyme linked immunosorbent assay (ELISA). Our detection limit of picomolar quantities of proteins is comparable to the best detection systems that have been reported.

KEYWORDS: MSN, detection, ELISA, signal amplification