A regenerative label-free fiber optic sensor using surface plasmon resonance for clinical diagnosis of fibrinogen

Abstract

Tan Tai Nguyen,1 Sun Oh Bea,1 Dong Min Kim,2 Won Jung Yoon,3 Jin-Won Park,4 Seong Soo A An,1 Heongkyu Ju1,5,6 1Department of Bionano Technology, College of Bionano Technology, Gachon University, Seongnam, 2Department of Materials Science and Engineering, Hongik University, Sejong City, 3Department of Chemical and Bio Engineering, Gachon University, Seongnam, 4Department of Chemical and Biomolecular Engineering, College of Energy and Biotechnology, Seoul National University of Science and Technology, Seoul, 5Department of Nanophysics, College of Bionano Technology, Gachon University, Seongnam, 6Neuroscience Institute, Gil Hospital, Incheon, South Korea Purpose: We present the regenerative label-free fiber optical biosensor that exploits surface plasmon resonance for quantitative detection of fibrinogen (Fbg) extracted from human blood plasma.Materials and methods: The sensor head was made up of a multimode optical fiber with its polymer cladding replaced by metal composite of nanometer thickness made of silver, aluminum, and nickel. The Ni layer coated allowed a direct immobilization of histidine-tagged peptide (HP) on its metal surface without an additional cross-linker in between. On the coated HP layer, immunoglobulin G was then immobilized for specific capturing of Fbg.Results: We demonstrated a real-time quantitative detection of Fbg concentrations with limit of detection of ~10 ng/mL. The fact that the HP layer could be removed by imidazole with acid also permitted us to demonstrate the regeneration of the outermost metal surface of the sensor head for the sensor reusability.Conclusion: The sensor detection limit was estimated to be ~10 pM, which was believed to be sensitive enough for detecting Fbg during the clinical diagnosis of cardiovascular diseases, myocardial infarction, strokes, and Alzheimer’s diseases. Keywords: SPR, real-time assay, histidine-tagged peptide, protein sensing