The rapid and sensitive detection of pepsin plays an important role in clinical and medical practice. A label-free and sensitive micro-tapered long-period fiber grating (MTLPFG) sensor that functionalized by graphene oxide (GO) was proposed for pepsin detection. MTLPFG was fabricated with CO₂ laser heating and tapered to form a series of periods, and the GO that activated oxygen groups by EDC/NHS was deposited onto MTLPFG surface. On account of large specific surface area and oxygen containing groups of GO, the biomolecules can be adsorbed on the GO surface through amide groups and π-π stacking. The spectrum variation trend during sensing process obeys Langmuir absorption mode, which illustrates biomolecule adsorption on GO layer. The bare MTLPFG and GO-MTLPFG separately demonstrate the limit of detection (LOD) of 104.6 ng/ml and 25.79 ng/ml, which corresponding to the effectively detection range of 1–1000 ng/ml. Combination of GO and optical fibers exhibit great adaptive capacity to the biosensors, and provides inspirations for biochemical sensing applications.

胃蛋白酶的快速灵敏检测在临床和医学实践中具有重要作用。提出了一种由氧化石墨烯 (GO) 功能化的无标记且灵敏的微锥形长周期光纤光栅 (MTLPFG) 传感器用于胃蛋白酶检测。MTLPFG 是用 CO _2制造的激光加热和锥形形成一系列周期，通过EDC/NHS活化氧基团的GO沉积在MTLPFG表面。由于GO的大比表面积和含氧基团，生物分子可以通过酰胺基团和π-π堆积吸附在GO表面上。传感过程中光谱变化趋势服从朗缪尔吸收模式，说明生物分子吸附在GO层上。裸 MTLPFG 和 GO-MTLPFG 的检测限 (LOD) 分别为 104.6 ng/ml 和 25.79 ng/ml，对应的有效检测范围为 1–1000 ng/ml。GO和光纤的结合对生物传感器表现出很强的适应能力，为生化传感应用提供了灵感。