Fabrication and measurement of a fiber optic localized surface plasmon resonance sensor chip for molecular diagnostics

Abstract

For several decades, the field of molecular diagnostics has been dominated by polymerase chain reaction technology, which usually entails relatively expensive equipment, trained laboratory staff, and problems in time management. Advances in molecular diagnostics aim to provide rapid tests, miniaturized devices, increased user convenience, and high sensitivity. The real-time label-free localized surface plasmon resonance (LSPR) biosensing technique merges with a small optical fiber and is combined with a microfluidic channel. This fiber optic LSPR sensor chip has the advantages of easy handling, isolation from the external environment, and continuous transport of sample fluid. The microfluidic channel can also accelerate hybridization by supplying the target to the sensor surface in succession. The conditions for the binding of probe deoxyribonucleic acids (DNAs) on gold nanoparticles are modified. Hybridization of the immobilized probe DNA and target DNA was analyzed using the proposed sensor and the results showed a good response to DNA hybridization with a limit of detection (LOD) level up to 12.3 ng/mL (1.5 nM). The LOD was compared with other LSPR-based DNA sensors and improvement was found. The proposed sensor responded with high linearity (R2 of 0.94) as a function of change in the concentration of the target DNA. Suitable reproducibility for biosensor applications was confirmed with an average coefficient of variation of 12.5 %.