Yuant Tiandho, Ni Luh Wulan Septiani, Riri Jonuarti, Suprijadi Suprijadi, Brian Yuliarto
Escherichia coli (E. coli) is a pathogen that often contaminates food products and infects humans. One strategy to control E. coli contamination can be implemented by regularly detecting E. coli. However, conventional detection of E. coli tends to be complicated and requires complex facilities. Therefore, developing biosensors to detect E. coli is an exciting topic because biosensors can perform fast and cheap detection. Gold nanoparticles (Au-NP) are commonly used in optical-based biosensors but have a disadvantage related to their figure of merit that needs improvement. In this work, we investigated the performance of Ag@Au nanoparticles as an optical-based biosensor to detect single E. coli pathogens at an early stage of biosensor development. The design of the Ag@Au nanoparticle structure aims to improve biosensor performance because silver has a sharply localized surface plasmon resonance (LSPR) peak, and gold has excellent stability. We used the finite difference time domain (FDTD) method to calculate the absorption spectrum of the nanoparticles immobilized by the bioreceptor and interacting with the E. coli model. Interaction between nanoparticles with E. coli leads to the localized surface plasmon resonance peak redshift. Although the shift in the LSPR peaks of Au-NP and Ag@Au-NP due to interacting with E. coli has the same value, the absorption spectrum of Ag@Au is sharper. It leads to the nanoparticle in the Ag@Au structure could have a better figure of merit than an Au-NP. © 2025 Author(s).
Doctoral Program of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung, Jawa Barat, 40132, Indonesia; Department of Physics, Universitas Bangka Belitung Kampus Terpadu UBB, Kep. Bangka Belitung, Bangka, 33172, Indonesia; Research Center for Advanced Materials, National Research and Innovation Agency (BRIN) Tangerang Selatan, Banten, Indonesia; Advanced Functional Materials Laboratory, Engineering Physics Department, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung, Jawa Barat, 40132, Indonesia; BRIN and ITB Collaboration Research Center for Biosensor and Biodevices, Jl. Ganesha 10, Bandung, Jawa Barat, 40132, Indonesia; Department of Physics, Universitas Negeri Padang, Jl. Prof. Dr. Hamka, Air Tawar Barat, Sumatera Barat, Padang, 25171, Indonesia; Department of Physics, Institut Teknologi Bandung, Jl. Ganesha 10 Bandung, Jawa Barat, 40132, Indonesia; Research Center for Nanoscience and Nanotechnology (RCNN), Institut Teknologi Bandung, Jl. Ganesha 10 Bandung, Jawa Barat, 40132, Indonesia
