BioMark, CEMMPRE, ARISE, Department of Chemical Engineering, Faculty of Sciences and Technology, University of Coimbra, Coimbra, Portugal; CENIMAT, i3N, Department of Materials Science, School of Science and Technology, NOVA University of Lisbon and CEMOP/UNINOVA, Caparica, Portugal.
BioMark, CEMMPRE, ARISE, Department of Chemical Engineering, Faculty of Sciences and Technology, University of Coimbra, Coimbra, Portugal.
Talanta. 2024 Nov 1;279:126543. doi: 10.1016/j.talanta.2024.126543. Epub 2024 Jul 10.
A state-of-the-art, ultrasensitive, paper-based SERS sensor has been developed using silver nanostars (AgNSs) in combination with synthetic and natural antibodies. A key component of this innovative sensor is the plastic antibody, which was synthesized using molecularly imprinted polymer (MIP) technology. This ground-breaking combination of paper substrates/MIPs with AgNSs, which is similar to a sandwich immunoassay, is used for the first time with the aim of SERS detection and specifically targets nucleolin (NCL), a cancer biomarker. The sensor device was carefully fabricated by synthesizing a polyacrylamide-based MIP on cellulose paper (Whatman Grade 1 filter) by photopolymerization. The binding of NCL to the MIP was then confirmed by natural antibody binding using a sandwich assay for quantitative SERS analysis. To facilitate the detection of NCL, antibodies were pre-bound to AgNSs with a Raman tag so that the SERS signal could indicate the presence of NCL. The composition of the sensory layers/materials was meticulously optimized. The intensity of the Raman signal at ∼1078 cm showed a linear trend that correlated with increasing concentrations of NCL, ranging from 0.1 to 1000 nmol L, with a limit of detection down to 0.068 nmol L in human serum. The selectivity of the sensor was confirmed by testing its analytical response in the presence of cystatin C and lysozyme. The paper-based SERS detection system for NCL is characterized by its simplicity, sustainability, high sensitivity and stability and thus embodies essential properties for point-of-care applications. This approach is promising for expansion to other biomarkers in various fields, depending on the availability of synthetic and natural antibodies.
一种基于银纳米星（AgNSs）的先进、超灵敏的纸基表面增强拉曼散射（SERS）传感器已被开发出来，该传感器结合了合成抗体和天然抗体。这种创新传感器的一个关键组成部分是塑料抗体，它是使用分子印迹聚合物（MIP）技术合成的。这种纸基底/MIPs 与 AgNSs 的结合类似于夹心免疫测定法，首次用于 SERS 检测，特别针对核仁素（NCL）这一癌症生物标志物。传感器装置通过光聚合在纤维素纸上（Whatman Grade 1 滤纸）合成基于聚丙烯酰胺的 MIP 来精心制造。然后通过使用夹心测定法进行定量 SERS 分析，确认 NCL 与 MIP 的天然抗体结合。为了便于检测 NCL，将抗体预先用拉曼标记物结合到 AgNSs 上，以便 SERS 信号可以指示 NCL 的存在。对敏感层/材料的组成进行了精心优化。在 ∼1078 cm 处的拉曼信号强度表现出与 NCL 浓度呈线性趋势，范围从 0.1 到 1000 nmol L，在人血清中的检测限低至 0.068 nmol L。通过测试在半胱氨酸蛋白酶抑制剂 C 和溶菌酶存在下的分析响应，确认了传感器的选择性。NCL 的纸基 SERS 检测系统具有简单、可持续、高灵敏度和稳定性的特点，因此体现了即时护理应用的基本特性。该方法有望根据合成抗体和天然抗体的可用性扩展到其他领域的生物标志物。
