Borjikhani Parisa, Granpayeh Nosrat, Zibaii Mohammad Ismail
Center of Excellence in Electromagnetics, Optical Communication Laboratory, Faculty of Electrical Engineering, K.N. Toosi University of Technology, Tehran, Iran.
Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, Iran.
Sci Rep. 2025 Jan 9;15(1):1458. doi: 10.1038/s41598-025-85739-z.
A localized surface plasmon resonance (LSPR) sensor based on tapered optical fiber (TOF) using hollow gold nanoparticles (HAuNPs) for measuring the refractive index (RI) is presented. This optical fiber sensor is a good candidate for a label-free RI biosensor. In practical biosensors, bioreceptors are immobilized on nanoparticles (NPs) that only absorb specific biomolecules. The binding of these biomolecules to the receptors changes the local RI around the sensor and this change is detected by the transmittance spectrum of the fiber. Fast, accurate, easy and low-cost disease diagnosis are the advantages of optical fiber biosensors. In this paper, the structure theory is reviewed and the sensor is simulated by the finite difference time domain (FDTD) method and the finite element method (FEM) and the effect of the thickness and diameter of the HAuNPs and the waist diameter of the TOF is investigated. For the structure with HAuNPs thickness (2.5 nm), diameter (50 nm), and the fiber waist diameter of 10 μm, the wavelength sensitivity of 489.8 nm/RIU and full width at half maximum (FWHM) of 50 nm are obtained, which are better than those specifications in some other LSPR fiber sensors. In addition, the sensitivity of the sensor increases about 2-3 times compared to those of sensors with the same structure. Although there are many parameters in human blood that can change its RI, in practical work, the special bioreceptors on the sensor can deactivate other markers except the specific cancer markers, which changes the effective RI. Therefore, this optical fiber sensor is used for label-free detecting the RI of cancer cells and can be used as a biosensor for the detection of early stages of cancers in a non-invasive way, just using human blood samples.
提出了一种基于锥形光纤（TOF）的局域表面等离子体共振（LSPR）传感器，该传感器使用中空金纳米粒子（HAuNP）来测量折射率（RI）。这种光纤传感器是无标记RI生物传感器的理想选择。在实际的生物传感器中，生物受体固定在仅吸收特定生物分子的纳米粒子（NP）上。这些生物分子与受体的结合会改变传感器周围的局部RI，并且这种变化通过光纤的透射光谱来检测。快速、准确、简便且低成本的疾病诊断是光纤生物传感器的优势。本文回顾了结构理论，并通过时域有限差分（FDTD）方法和有限元方法（FEM）对传感器进行了模拟，研究了HAuNP的厚度和直径以及TOF的腰径的影响。对于HAuNP厚度为2.5nm、直径为50nm且光纤腰径为10μm的结构，获得了489.8nm/RIU的波长灵敏度和50nm的半高全宽（FWHM），这优于其他一些LSPR光纤传感器的规格。此外，与具有相同结构的传感器相比，该传感器的灵敏度提高了约2至3倍。尽管人血中有许多参数会改变其RI，但在实际工作中，传感器上的特殊生物受体可以使除特定癌症标志物之外的其他标志物失活，从而改变有效RI。因此，这种光纤传感器用于无标记检测癌细胞的RI，并且仅使用人血样本就可以作为以非侵入性方式检测癌症早期阶段的生物传感器。
