Performance enhancement of a prism-based label-free SPR biosensor using a Cu/Si₃N₄/Al₂O₃ multilayer structure for cancer detection.
- 1Department of Electrical and Electronic Engineering, Khulna University of Engineering & Technology Khulna 9203 Bangladesh [email protected].
- 2Department of Electrical and Electronic Engineering, Bangladesh Army University of Engineering & Technology Natore 6431 Bangladesh.
- 3Department of Electrical and Electronic Engineering, Rajshahi University of Engineering & Technology Rajshahi 6204 Bangladesh.
Abstract
Surface plasmon resonance (SPR) biosensors are becoming more and more popular in label-free and highly sensitive biomedical sensing. However, they generally suffer from limited sensitivity and poor resonance stability, which restrict their practical biomedical sensing performance. Considering these, a prism-coupled multilayer SPR biosensor with the configuration BK7/Cu/Si3N4/Al2O3/analyte is proposed in this study for cancer cell detection. The sensor design is modeled and analyzed using the transfer matrix method (TMM) and further validated through finite element method (FEM) simulations. The optimized configuration consisting of Cu (50 nm), Si3N4 (10 nm), and Al2O3 (2 nm) achieves a maximum sensitivity of 446.07 deg per RIU with a resonance angle shift of 6.245° for breast cancer detection. The corresponding detection accuracy and quality factor are found to be 0.293 deg-1 and 130.62 RIU-1, respectively. Compared with the conventional BK7/Cu/analyte configuration, the proposed multilayer structure exhibits nearly 2.7 times higher sensitivity. The incorporation of the Si3N4 layer improves electromagnetic field confinement at the sensing interface, which contributes to improved sensor response. Additionally, the Al2O3 layer together with Si3N4 helps suppress Cu oxidation and supports stable resonance characteristics. A fabrication tolerance analysis with ±2% thickness variation shows that the maximum sensitivity deviation remains within 6.97%, indicating good structural robustness. The proposed sensor exhibits good linearity within the refractive index range of 1.360-1.399. The electric field distribution indicates evanescent field penetration into the analyte region with an estimated penetration depth of approximately 174 nm, allowing effective interaction between the sensing medium and the plasmonic field. In addition to breast cancer cells, the proposed sensor also shows promising response for adrenal gland, blood, cervical, and skin cancer cells with sensitivities of 347.14, 281.43, 267.71, and 210.00 deg per RIU, respectively. These results demonstrate the potential of the suggested SPR biosensor for biomedical sensing applications including cancer diagnosis.
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BibTeX
@article{islam2026performance,
title = {{Performance enhancement of a prism-based label-free SPR biosensor using a Cu/Si₃N₄/Al₂O₃ multilayer structure for cancer detection.}},
author = {Md Nazmul Islam and Md Tawabur Rahman and Al-Hadith Moon and Md Emon Hasan Sourav and Biswajit Dey and Arnab Saha},
journal = {Nanoscale advances},
year = {2026},
month = oct,
doi = {10.1039/d6na00669h},
url = {https://europepmc.org/article/MED/42953683},
note = {CC BY-NC},
}
RIS
TY - JOUR
TI - Performance enhancement of a prism-based label-free SPR biosensor using a Cu/Si₃N₄/Al₂O₃ multilayer structure for cancer detection.
AU - Md Nazmul Islam
AU - Md Tawabur Rahman
AU - Al-Hadith Moon
AU - Md Emon Hasan Sourav
AU - Biswajit Dey
AU - Arnab Saha
PY - 2026
DA - 2026/10/13
JO - Nanoscale advances
DO - 10.1039/d6na00669h
UR - https://europepmc.org/article/MED/42953683
AB - Surface plasmon resonance (SPR) biosensors are becoming more and more popular in label-free and highly sensitive biomedical sensing. However, they generally suffer from limited sensitivity and poor resonance stability, which restrict their practical biomedical sensing performance. Considering these, a prism-coupled multilayer SPR biosensor with the configuration BK7/Cu/Si3N4/Al2O3/analyte is proposed in this study for cancer cell detection. The sensor design is modeled and analyzed using the transfer matrix method (TMM) and further validated through finite element method (FEM) simulations. The optimized configuration consisting of Cu (50 nm), Si3N4 (10 nm), and Al2O3 (2 nm) achieves a maximum sensitivity of 446.07 deg per RIU with a resonance angle shift of 6.245° for breast cancer detection. The corresponding detection accuracy and quality factor are found to be 0.293 deg-1 and 130.62 RIU-1, respectively. Compared with the conventional BK7/Cu/analyte configuration, the proposed multilayer structure exhibits nearly 2.7 times higher sensitivity. The incorporation of the Si3N4 layer improves electromagnetic field confinement at the sensing interface, which contributes to improved sensor response. Additionally, the Al2O3 layer together with Si3N4 helps suppress Cu oxidation and supports stable resonance characteristics. A fabrication tolerance analysis with ±2% thickness variation shows that the maximum sensitivity deviation remains within 6.97%, indicating good structural robustness. The proposed sensor exhibits good linearity within the refractive index range of 1.360-1.399. The electric field distribution indicates evanescent field penetration into the analyte region with an estimated penetration depth of approximately 174 nm, allowing effective interaction between the sensing medium and the plasmonic field. In addition to breast cancer cells, the proposed sensor also shows promising response for adrenal gland, blood, cervical, and skin cancer cells with sensitivities of 347.14, 281.43, 267.71, and 210.00 deg per RIU, respectively. These results demonstrate the potential of the suggested SPR biosensor for biomedical sensing applications including cancer diagnosis.
SN - 2516-0230
ER -