Sensitivity enhancement with coating of Si and ZnO and two-dimensional nanomaterials in silver-based SPR biosensor for DNA hybridization

Here, a high-sensitivity silver-based surface plasmon resonance biosensor by a coating of zinc oxide on silicon for detecting hybridization of DNA is reported numerically. By changing the surface plasmon resonance angle and the minimum reflectance, this proposed biosensor can examine the difference between matched and mismatched DNA strands, as well as the nucleotide bonding between double-stranded (dsDNA) helix structures, and recognize the hybridization of target DNAs by using probe DNA immobilized on zinc oxide in the proper orientation. Also, the methodology of this work can detect single nucleotide polymorphisms (SNP). Using the transfer matrix method, we investigated the performance parameters of the biosensor. We observed that our proposed sensor has a maximum sensitivity of 378.36 deg/RIU and a good quality factor of 71.183 RIU⁻¹. As we can see, compared with other reported papers, our proposed biosensor shows much better performance. This paper uses the biocompatibility, the electrical properties, the chemical stability, and high affinity of both Si and ZnO in surface plasmon resonance biosensors for the hybridization of DNA.