We present graphene oxide (GO) nanosheets functionalized long period grating (LPG) for ultrasensitive hemoglobin sensing. The sensing mechanism relies on the measurement of LPG resonant intensity change induced by the adsorption of hemoglobin molecules onto GO, where GO as a bio-interface linkage provides the significant light-matter interaction between evanescent field and target molecules. The deposition technique based on chemical-bonding associated with physical-adsorption was developed to immobilize GO nanosheets on cylindrical fiber device. The surface morphology was characterized by scanning electron microscope, atomic force microscopy, and Raman spectroscopy. With relatively thicker GO coating, the refractive index (RI) sensitivity of GO-LPG was extremely enhanced and achieved −76.5 dB/RIU, −234.2 dB/RIU and +1580.5 dB/RIU for RI region of 1.33–1.38, 1.40–1.44 and 1.45–1.46, respectively. The GO-LPG was subsequently implemented as an optical biosensor to detect human hemoglobin giving a sensitivity of 1.9 dB/(mg/mL) and a detectable concentration of 0.05 mg/mL, which was far below the hemoglobin threshold value for anemia defined by World Health Organization. The proposed GO-LPG architecture can be further developed as an optical biosensing platform for anemia diagnostics and biomedical applications.

我们目前为超灵敏的血红蛋白传感功能化的氧化石墨烯（GO）纳米片功能化的长周期光栅（LPG）。感测机制依赖于血红蛋白分子吸附到GO上引起的LPG共振强度变化的测量，其中GO作为生物界面连接提供了van逝场与目标分子之间显着的光-质相互作用。开发了基于化学键合和物理吸附的沉积技术，以将GO纳米片固定在圆柱形纤维器件上。通过扫描电子显微镜，原子力显微镜和拉曼光谱对表面形态进行表征。使用相对较厚的GO涂层，可以极大地提高GO-LPG的折射率（RI）灵敏度，并达到-76.5 dB / RIU，-234.2 dB / RIU和+1580。对于RI区域1.33–1.38、1.40–1.44和1.45–1.46，分别为5 dB / RIU。GO-LPG随后被用作光学生物传感器，用于检测人类血红蛋白，其灵敏度为1.9 dB /（mg / mL），可检测浓度为0.05 mg / mL，该浓度远低于World定义的贫血的血红蛋白阈值卫生组织。所提出的GO-LPG体系结构可以进一步发展为一种用于贫血诊断和生物医学应用的光学生物传感平台。