在这项研究中，我们提出了一种新型生物标志物检测平台，采用涂有金纳米颗粒/氧化石墨烯 (GNP/GO) 的改良 S 锥形纤维，使用抗体作为传感元件来量化人表皮生长因子受体 2 (HER2) 浓度。该器件的制造涉及实施原位逐层技术与化学吸附步骤相结合，以实现 GNP、GO 和抗体在 STF 表面上的自组装。检测机制依赖于监测 HER2 吸附到固定抗体上引起的折射率变化。为了进行比较分析，采用单克隆抗体（mAb）和新型纳米抗体（Nb）构建STF免疫传感器，分别称为mAb免疫传感器和Nb免疫传感器。光谱分析结果强调，Nb 免疫传感器的灵敏度是 mAb 免疫传感器的两倍。这种增强的灵敏度归因于 Nb 的小尺寸、高抗原亲和力、强特异性和结构稳定性。 Nb 免疫传感器对 HER2 的检测限高达 0.001 nM，超过了 mAb 免疫传感器的检测限。这些发现强调了所提出的 Nb 免疫传感器作为 HER2 检测的有前途且灵敏的工具的潜力，有助于乳腺癌的诊断和预后。此外，生产的简单性和出色的光学性能使 Nb 免疫传感器成为具有最小细胞毒性的前瞻性实时生物传感器。版权所有 © 2024 Elsevier B.V. 保留所有权利。

In this study, we present a novel biomarker detection platform employing a modified S-tapered fiber coated with gold nanoparticle/graphene oxide (GNP/GO) for quantifying human epidermal growth factor receptor-2 (HER2) concentrations, using antibodies as sensing elements. The fabrication of this device involves implementing an in-situ layer-by-layer technique coupled with a chemical adsorption step to achieve the self-assembly of GNP, GO, and antibodies on the STF surface. The detection mechanism relies on monitoring the refractive index changes induced by the adsorption of HER2 onto the immobilized antibodies. For comparative analysis, both monoclonal antibody (mAb) and the novel nanobody (Nb) were employed in constructing the STF immunosensor, referred to as the mAb immunosensor and Nb immunosensor, respectively. Spectral analysis results highlight that the Nb immunosensor exhibits twice the sensitivity of the mAb immunosensor. This enhanced sensitivity is attributed to the small size, high antigen affinity, strong specificity, and structural stability of Nb. The Nb immunosensor demonstrated an impressive detection limit of 0.001 nM for HER2, surpassing the detection limit of the mAb immunosensor. These findings underscore the potential of the proposed Nb immunosensor as a promising and sensitive tool for HER2 detection, contributing to the diagnosis and prognosis of breast cancer. Furthermore, the simplicity of production and excellent optical performance position the Nb immunosensor as a prospective real-time biosensor with minimal cytotoxicity.Copyright © 2024 Elsevier B.V. All rights reserved.