Optimally Configured Optical Fiber Near‐Field Enhanced Plasmonic Resonance Immunoprobe for the Detection of Alpha‐Fetoprotein

Abstract

The detection of trace biomarkers is an important supplementary approach for early screening and diagnoses of tumors. An optical fiber near‐field enhanced plasmonic resonance immunoprobe is developed for the detection of the hepatocellular carcinoma biomarker, i.e., the alpha‐fetoprotein. Generic principles based on dispersion models and finite element analysis (FEA) models are developed to realize the optimized configuration of spectral characteristics of the immunoprobe. Dispersion models provide theoretical guidance for the design of the multilayer sensing structure from the perspective of the ray optics theory. FEA models provide theoretical guidance for the selection of coating materials from the perspective of the self‐defined dielectric constant ratio, i.e., the ratio of the real part to the imaginary part. The optimized configuration of the antibody coupling further improves the biosensing performance of the immunoprobe. The limit of detection (LOD) can reach down to 0.01 ng mL−1, which is one order of magnitude lower than those relevant reported works. Such a low LOD can more effectively avoid the accuracy degradation of detection results due to measurement errors. Human serum samples have also been detected, with the good precision achieved. This work shows promising prospects in applications of label‐free, low‐cost, rapid, and convenient early screening of tumors.

Violet phosphorus-enhanced plug-and-play double-lane fiber optic surface plasmon resonance refractometer

“…依托光纤基底激发SPR即可构建 光纤SPR传感器, 其基本传感结构为光纤/金属层/ 样品层 [4] . 当光纤中的光入射至金属层下表面时, 金属层表面自由电子发生集体振荡形成表面等离 激元(surface plasmons, SPs) [5] . 当入射光产生的 倏逝场横向波矢与SPs横向波矢相等时, 入射光 中的能量大部分耦合至SPs中并激发表面等离极 化激元(surface plasmon polaritons, SPPs), 传感 器传输光谱中出现共振谷 [6] .…”

“…较窄. 此外, 基于紫磷的高折射率特性, 紫磷层与 光纤纤芯杂化为高折射率基底位于金层下方, 使得 该类型共振激发于较高频率处 [5] , 即共振激发波段 相比于单金属层共振激发波段红移不明显. 损耗谷2分别为近场增强型和近导波型结构激发, 基模损耗光谱源于SPR效应引起的光场能量损 耗, 可代表传感器的共振光谱 [5] .…”

“…所示. 由于共振匹配条件发生在更低频率处以及紫 磷对SPPs损耗特性的调制作用 [5] , 该类型折射率 计共振光谱相比于单金层光纤SPR折射率计发生 明显红移和展宽. 该类型折射率计平均灵敏度如 图9(b)所示.…”

Co-Reactive Ligand In Situ Engineered Gold Nanoclusters with Ultra-Bright Near-Infrared Electrochemiluminescence for Ultrasensitive and Label-Free Detection of Carboxylesterase Activity

“…Although alpha-fetoprotein (AFP) is a typical serologic biomarker for HCC in early diagnosis, the detection of AFP cannot efficiently distinguish HCC from other liver diseases because of limited sensitivity or specificity. 3,4 Fortunately, carboxylesterase (CE) (EC 3.1.1.1), one of the most abundant serine hydrolases responsible for the metabolism of various xenobiotics in the human liver, could serve as an efficient serological biomarker candidate for HCC because the difference between HCC and liver cirrhosis is significant compared to that with AFP. 5,6 Currently, commercial kits have been used to determine CE activity with a colorimetric assay, which suffers from a relatively low sensitivity.…”

“…Hepatocellular carcinoma (HCC), as the most common type of primary liver cancer, has a terrible survival rate (<5% during 5 years) owing to the overwhelming number of patients that are diagnosed late, leading to terrible treatment. , A noninvasive and accurate diagnosis of HCC undoubtedly holds crucial promise in improving patient survival. Although alpha-fetoprotein (AFP) is a typical serologic biomarker for HCC in early diagnosis, the detection of AFP cannot efficiently distinguish HCC from other liver diseases because of limited sensitivity or specificity. , Fortunately, carboxylesterase (CE) (EC 3.1.1.1), one of the most abundant serine hydrolases responsible for the metabolism of various xenobiotics in the human liver, could serve as an efficient serological biomarker candidate for HCC because the difference between HCC and liver cirrhosis is significant compared to that with AFP. , Currently, commercial kits have been used to determine CE activity with a colorimetric assay, which suffers from a relatively low sensitivity. Very recently, various fluorescent probes have been designed to achieve sensitive detection for CE activity, but these still have the disadvantage of low selectivity in a biological matrix and poor resistance to photobleaching. − Electrochemiluminescence (ECL), as a powerful analytical technique, showcases outstanding advantages of near-zero background, convenient operation, and high sensitivity, − paving a promising opportunity for the sensitive detection of CE activity, but no reports are available about this.…”