ORIGINAL RESEARCH article

Front. Bioeng. Biotechnol.

Sec. Biosensors and Biomolecular Electronics

Volume 13 - 2025 | doi: 10.3389/fbioe.2025.1577925

Numerical Analysis of WS2/Si3N4 for Improved SPR-Based HIV DNA Detection

Provisionally accepted
Talia  TeneTalia Tene1*Yesenia  CevallosYesenia Cevallos2Jessica  Alexandra Marcatoma TixiJessica Alexandra Marcatoma Tixi3Natalia  Alexandra Pérez LondoNatalia Alexandra Pérez Londo3Lala  GahramanliLala Gahramanli4Cristian  Vacacela GomezCristian Vacacela Gomez5*
  • 1Universidad Técnica Particular de Loja, Loja, Loja, Ecuador
  • 2National University of Chimborazo, Riobamba, Chimborazo, Ecuador
  • 3Escuela Superior Politécnica del Chimborazo, Riobamba, Chimborazo, Ecuador
  • 4Baku State University, Baku, Azerbaijan
  • 5National Laboratory of Frascati (INFN), Frascati, Italy

The final, formatted version of the article will be published soon.

Surface-plasmon-resonance (SPR) sensors provide label-free nucleic-acid diagnostics, yet they must detect the sub-nanometre refractive-index changes generated by short HIV-DNA hybridisation. Using a transfer-matrix framework, we design a multilayer architecture that couples a 50 nm silver mirror to the analyte through a 7 nm (10 nm) silicon-nitride spacer capped with a monolayer of WS₂. This impedance-matched stack (Sys₃) concentrates the evanescent field at the recognition surface while chemically passivating the metal. Numerical screening calibrated with published optical constants predicts an angular sensitivity of 167 ° RIU⁻¹, a limit of detection of 2.99 × 10⁻⁵ RIU and a quality factor of 56.9 RIU⁻¹, outperforming gold-based benchmarks and approaching values reported for more reactive ZnSe buffers. Reversing the dielectric sequence (Sys₄) increases sensitivity to 201 ° RIU⁻¹ but lowers fabrication yield and storage stability, establishing Sys₃ as the most scalable option.Proof-of-concept measurements demonstrate sub-picomolar quantification of HIV DNA in phosphatebuffered saline without enzymatic amplification. The materials palette is compatible with complementary-metal-oxide-semiconductor processes, enabling streamlined integration of highresolution SPR sensing into point-of-care viral-load platforms for resource-limited settings.

Keywords: Surface Plasmon Resonance, HIV DNA Hybridization, Kretschmann configuration, transfer matrix method, silicon nitride, Tungsten disulfide

Received: 16 Feb 2025; Accepted: 07 Jul 2025.

Copyright: © 2025 Tene, Cevallos, Marcatoma Tixi, Pérez Londo, Gahramanli and Vacacela Gomez. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Talia Tene, Universidad Técnica Particular de Loja, Loja, 1101608, Loja, Ecuador
Cristian Vacacela Gomez, National Laboratory of Frascati (INFN), Frascati, Italy

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