A label-free fiber biosensor based on Erbium-doped fiber laser (EDFL) integrated singlemode – tapered quad-core -singlemode fiber (STQS) structure is proposed and demonstrated for the detection of TNF-α. An excessive level of TNF-α in the body is an indicator for a number of serious health conditions. The sensor head structure is constructed by splicing and tapering a short section quad-core fiber (length 20 mm, diameter 5.45 µm) between two single-mode fibers. Antibodies of tumor necrosis factor-α (TNF-α) are then immobilized on the surface of the STQS structure to realize specifical binding with TNF-α. An EDFL is integrated to the sensor system to improve sensor resolution due to its high Quality (Q) factor of laser. Experimental result shows that the EDFL integrated STQS biosensor can detect TNF-α in solution with a concentration as low as 10 pg/mL (diluted by phosphate buffered saline) with an average wavelength shift of 0.59 nm. Human blood samples from three patients (TNF-α concentrations vary from 10 to 30 pg/mL) have been tested using the developed biosensor and the results agree well with standard method of flow immunofluorescence luminescence assay used in a hospital setting.

中文翻译：

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用于人体血液样本中TNF-α检测的超高灵敏度光纤激光集成生物传感器


提出并演示了一种基于掺铒光纤激光器（EDFL）集成单模-锥形四核单模光纤（STQS）结构的无标记光纤生物传感器，用于检测TNF-α。体内 TNF-α 水平过高是许多严重健康状况的指标。传感器头结构是通过在两个单模光纤之间拼接和逐渐变细短截面四芯光纤（长度 20 mm，直径 5.45 µm）而构建的。然后将肿瘤坏死因子-α（TNF-α）的抗体固定在STQS结构的表面，实现与TNF-α的特异性结合。 EDFL 集成到传感器系统中，由于其激光质量 (Q) 系数较高，可提高传感器分辨率。实验结果表明，EDFL集成STQS生物传感器可以检测浓度低至10 pg/mL（用磷酸盐缓冲盐水稀释）的溶液中的TNF-α，平均波长漂移为0.59 nm。使用开发的生物传感器对三名患者的人体血液样本（TNF-α 浓度从 10 至 30 pg/mL 不等）进行了测试，结果与医院环境中使用的流式免疫荧光发光测定的标准方法非常吻合。