School of Electronic Engineering, Bangor University, Bangor LL57 1UT, United Kingdom.
School of Electronic Engineering, Bangor University, Bangor LL57 1UT, United Kingdom; State Key Laboratory of Transducer Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China.
Biosens Bioelectron. 2017 Aug 15;94:200-206. doi: 10.1016/j.bios.2017.03.004. Epub 2017 Mar 9.
We explore graphene oxide (GO) nanosheets functionalized dual-peak long period grating (dLPG) based biosensor for ultrasensitive label-free antibody-antigen immunosensing. The GO linking layer provides a remarkable analytical platform for bioaffinity binding interface due to its favorable combination of exceptionally high surface-to-volume ratio and excellent optical and biochemical properties. A new GO deposition technique based on chemical-bonding in conjunction with physical-adsorption was proposed to offer the advantages of a strong bonding between GO and fiber device surface and a homogeneous GO overlay with desirable stability, repeatability and durability. The surface morphology of GO overlay was characterized by Atomic force microscopy, Scanning electron microscope, and Raman spectroscopy. By depositing the GO with a thickness of 49.2nm, the sensitivity in refractive index (RI) of dLPG was increased to 2538nm/RIU, 200% that of non-coated dLPG, in low RI region (1.333-1.347) where bioassays and biological events were usually carried out. The IgG was covalently immobilized on GO-dLPG via EDC/NHS heterobifunctional cross-linking chemistry leaving the binding sites free for target analyte recognition. The performance of immunosensing was evaluated by monitoring the kinetic bioaffinity binding between IgG and specific anti-IgG in real-time. The GO-dLPG based biosensor demonstrates an ultrahigh sensitivity with limit of detection of 7ng/mL, which is 10-fold better than non-coated dLPG biosensor and 100-fold greater than LPG-based immunosensor. Moreover, the reusability of GO-dLPG biosensor has been facilitated by a simple regeneration procedure based on stripping off bound anti-IgG treatment. The proposed ultrasensitive biosensor can be further adapted as biophotonic platform opening up the potential for food safety, environmental monitoring, clinical diagnostics and medical applications.
我们探索了基于氧化石墨烯（GO）纳米片功能化的双峰长周期光栅（dLPG）的生物传感器，用于超灵敏无标记抗体-抗原免疫传感。GO 连接层由于其极高的比表面积和出色的光学和生化特性，为生物亲和结合界面提供了卓越的分析平台。提出了一种基于化学键合与物理吸附相结合的新型 GO 沉积技术，以提供 GO 与光纤器件表面之间强键合以及具有理想稳定性、可重复性和耐用性的均匀 GO 覆盖层的优势。通过原子力显微镜、扫描电子显微镜和拉曼光谱对 GO 覆盖层的表面形态进行了表征。通过沉积厚度为 49.2nm 的 GO，使 dLPG 的折射率（RI）灵敏度提高到 2538nm/RIU，是未涂层 dLPG 的 200%，在生物测定和生物事件通常进行的低 RI 区域（1.333-1.347）。IgG 通过 EDC/NHS 异双功能交联化学共价固定在 GO-dLPG 上，使结合位点保持自由，用于目标分析物的识别。通过实时监测 IgG 与特异性抗-IgG 之间的动力学生物亲和结合来评估免疫传感的性能。基于 GO-dLPG 的生物传感器具有超高的灵敏度，检测限为 7ng/mL，比未涂层的 dLPG 生物传感器灵敏 10 倍，比基于 LPG 的免疫传感器灵敏 100 倍。此外，通过基于剥离结合的抗-IgG 处理的简单再生程序，促进了 GO-dLPG 生物传感器的可重复使用性。所提出的超灵敏生物传感器可以进一步适应作为生物光子平台，为食品安全、环境监测、临床诊断和医疗应用开辟了潜力。
