State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering , Zhejiang University , Hangzhou 310027 , China.
ACS Sens. 2019 Sep 27;4(9):2267-2271. doi: 10.1021/acssensors.9b00913. Epub 2019 Aug 9.
A challenge for optofluidic absorbance detection is the high concentration limit of detection due to the short optical path length. Herein, we introduce a concept of utilizing the coiled optical nanofiber for highly sensitive and robust optofluidic absorbance detection. Investigated by measuring the absorbance of FeCl solutions, the sensor shows a detection limit down to 10 μM with excellent reversibility in a concentration range of 0-5 mM. The sensitivity is 10-fold higher than that of standard absorbance measurement by using a 1 cm cuvette. Also, highly sensitive chloramphenicol sensing was demonstrated by using the enzyme-linked immunosorbent assay (ELISA) method, achieving a detection limit below 0.5 ng/L. The higher sensitivity and lower detection limit are caused by the large fractional power of evanescent field outside the nanofiber and the long detection length, which can effectively improve the absorption of the evanescent field, while the excellent reversibility is caused by the support of a polydimethylsiloxane (PDMS) pillar rather than by suspending the nanofiber in the microchannel. We envision that the present work may open up new opportunities for ultrasensitive chemical and biological sensing.
光流吸光度检测的一个挑战是由于光程短而导致的高浓度检测限。在此，我们介绍了一种利用螺旋光纤进行高灵敏度和稳健的光流吸光度检测的概念。通过测量 FeCl 溶液的吸光度来进行研究，该传感器在 0-5mM 的浓度范围内显示出低至 10μM 的检测限，且具有优异的可逆性。其灵敏度比使用 1cm 比色皿的标准吸光度测量方法高 10 倍。此外，还通过酶联免疫吸附测定（ELISA）方法展示了对氯霉素的高灵敏度传感，检测限低于 0.5ng/L。更高的灵敏度和更低的检测限是由于纳米光纤外倏逝场的大分数幂和长检测长度引起的，这可以有效地提高倏逝场的吸收，而优异的可逆性则是由于支撑物是聚二甲基硅氧烷（PDMS）柱而不是将纳米光纤悬浮在微通道中。我们预计，本工作可能为超灵敏的化学和生物传感开辟新的机会。
