Ultrasensitive and high selectivity detection of fibrin using Y-shaped DNA-homing peptide doped probe on localized surface plasmon resonance platform.

Background: Localized surface plasmon resonance (LSPR) sensor has drawn continuous attention to application of the detection of antibody, protein, virus, and bacteria. However, natural recognition molecules, such as antibody, which possess some properties, including low thermal stability, complicated operation and high price, uncontrollability of length and size and a tendency to accumulate easily on the surface of chip to reduce the sensitive of method. Furthermore, common blocking agents are not suitable for development of novel biosensors. There is a significant demand for an innovative artificial probe that can meet the high recognition capabilities and ultrasensitive required by LSPR sensors.

Results: A LSPR sensor was developed for ultrasensitive detection of fibrin with a Y-shaped DNA-homing peptide doped probe. The Y-shaped probe, composed of three single stranded DNA (ssDNA), was immobilized on AuNPs chip. The two arms of Y-shaped probe were functionalized with homing peptides capable of recognizing fibrin. Additionally, in combination with the hybridization chain reaction, the growth of the arms facilitated enhanced functionalization with homing peptides to improve the sensitivity of method. Furthermore, ssDNA with a G-quadruplex structure acted as a novel blocking agent and was immobilized on the surface of the LSPR chip to minimize non-specific adsorption. Ultimately, remarkable changes in the LSPR signal were observed upon introduction of fibrin. Under optimized experimental conditions, the response of the LSPR biosensor followed a linear regression equation ΔLSPR = 5420.53 + 395.14lgC (where C represents the concentration of fibrin in mol L), exhibiting a high linear correlation coefficient R = 0.9979 and attaining a limit of detection of 1 × 10 mol L.

Significance: It is believed that this work holds promising potential for the Y-shaped DNA-homing peptide doped probe, which takes advantage of the DNA structure with nanometer precision through programmable hybridization and the specific recognition of the homing peptide. Herein the developed LSPR biosensing platform demonstrated outstanding specificity and ultrasensitivity, rendering it suitable for early cancer screening.