Ultra-sensitive detection of O-GlcNAc transferase based on micro-structured optical fiber biosensor with enhanced fluorescence collection

Abstract

The development of optical fiber-based biosensors is greatly promoted by the increasing demand for simple, rapid and miniaturized analytical devices for accurate and sensitive detection of biomolecules in the clinical diagnosis, biomedicine and pharmaceutical fields. O-GlcNAc transferase (OGT) is considered to be a novel promising therapeutic target for disease diagnosis since it is closely related to O-linked-β-N-acetylglucosamine glycosylation (O-GlcNAcylation). At present, the detection and study of OGT has been hampered by its ultralow cellular abundance and low stability of enzyme activity. Here we present a micro-structured optical fiber (MSOF)-based biosensor for ultra-sensitive analysis of OGT. We utilize MSOF as carrier to immobilize fluorescence-labeled peptide based on streptavidin-biotin affinity and non-radioactive UDP-GlcNAc as sugar donor to perform O-GlcNAc glycosylation modification. Moreover, we improve the laser-induced fluorescence (LIF) system by combining concave mirror and microscope objective as fluorescence collector to further enhance the detection sensitivity. With the advantages of large surface area of MSOF and high fluorescence collection efficiency, the MSOF-biosensor shows an ultralow limit-of-detection of 3.40 × 10−2 pM for OGT assays. The feasibility of its clinical application has also been demonstrated by the analysis of blood samples from breast cancer patients, providing a promising analysis platform for sensitive diagnosis of OGT.