Probe type optical fiber DNA hybridization biosensor based on polyethylenimine and Poly-L-Lysine surface functionalization method

Nucleotide hybridization technology is an effective method for achieving optical-based selective recognition of nucleotides. Unfortunately, the optimal work performance is always restricted by the lack of the coupling method used to bind sensors with nucleotide sequences. In this work, a series of nucleotide hybridization detection experiments based on optical fiber surface plasmon resonance (SPR) are conducted, aimed at comparing the ability to bind nucleotide of Polyethylenimine (PEI) and Poly-L-Lysine (PLL), which are common coupling agents in optical-based nucleotide hybridization study. In our work, qualitative nucleotide measurements using PEI and PLL are carried out in positive order, negative order, and temperature fluctuation, and confirm PEI has a higher work performance in nucleotide-binding and nucleotide-detection. Quantitative determination in the concentration range of 0–100 nmol/L demonstrates the DNA sensitivity reaches 0.13 nm/(nmol/L) and the detection limit (DL) lies in 4.9 nmol/L, which is outstanding compared with similar optical sensors. In this paper, two kinds of nucleotide molecule detection methods based on optical fiber SPR sensing technology with PEI and PLL are proposed and experimentally verified, and the nucleotide-binding capability of PLL and PEI is contrast analyzed according to experimental results for the first time. This study is of great significance for improving the measurement scheme of DNA sensors and the selection of gene carriers for manufacturing DNA complexes.