The cucurbit[n]uril (CB[n]) family of macrocycles are known to bind a variety of small molecules with high affinity. These motifs thus have promise in an ever-growing list of trace detection methods. Surface-enhanced Raman scattering (SERS) detection schemes employing CB[n] motifs exhibit increased sensitivity due to selective concentration of the analyte at the nanoparticle surface, coupled with the ability of CB[n] to facilitate the formation of well-defined electromagnetic hot spots. Herein, we report a CB[7] SERS assay for quantification of phenylalanine (Phe) and further demonstrate its utility for detecting peptides with an N-terminal Phe. The CB[7]–guest interaction improves the sensitivity 5–25-fold over direct detection of Phe using citrate-capped silver nanoparticle aggregates, enabling use of a portable Raman system. We further illustrate detection of insulin via binding of CB[7] to the N-terminal Phe residue on its B-chain, suggesting a general strategy for detecting Phe-terminated peptides of clinically relevant biomolecules.

中文翻译：

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EXPRESS：使用超分子大环捕获苯丙氨酸和苯丙氨酸末端肽用于表面增强拉曼散射检测

葫芦[n]uril (CB[n]) 大环家族已知能以高亲和力结合多种小分子。因此，这些基序在不断增长的痕量检测方法列表中具有前景。采用 CB[n] 基序的表面增强拉曼散射 (SERS) 检测方案由于分析物在纳米颗粒表面的选择性浓度而表现出更高的灵敏度，再加上 CB[n] 促进形成明确的电磁热的能力斑点。在此，我们报告了一种用于定量苯丙氨酸 (Phe) 的 CB[7] SERS 测定，并进一步证明了其在检测具有 N 端 Phe 的肽方面的实用性。与使用柠檬酸盐封端的银纳米粒子聚集体直接检测 Phe 相比，CB[7]-客体相互作用将灵敏度提高了 5-25 倍，从而能够使用便携式拉曼系统。