Morsby Janeala J, Thimes Rebekah L, Olson Jacob E, McGarraugh Hannah H, Payne Jason N, Camden Jon P, Smith Bradley D
Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, Indiana 46556-5670, Unites States.
ACS Omega. 2022 Feb 9;7(7):6419-6426. doi: 10.1021/acsomega.2c00139. eCollection 2022 Feb 22.
The high sensitivity and functional group selectivity of surface-enhanced Raman scattering (SERS) make it an attractive method for enzyme sensing, but there is currently a severe lack of enzyme substrates that release SERS reporter molecules with favorable detection properties. We find that 2-mercaptopyridine-3-carbonitrile ( ) and 2-mercaptopyridine-5-carbonitrile ( ) are highly effective as SERS reporter molecules that can be captured by silver or gold nanoparticles to give intense SERS spectra, each with a distinctive nitrile peak at 2230 cm. is a more sensitive reporter and can be detected at low nanomolar concentrations. An assay validation study synthesized two novel substrate molecules, and , and showed that they can be cleaved efficiently by β-glucosidase ( = 228 and 162 μM, respectively), an enzyme with broad industrial and biomedical utility. Moreover, SERS detection of the released reporters ( or ) enabled sensing of β-glucosidase activity and β-glucosidase inhibition. Comparative experiments using a crude almond flour extract showed that the presence of β-glucosidase activity could be confirmed by SERS detection in a much shorter time period (>10 time shorter) than by UV-vis absorption detection. It is likely that a wide range of enzyme assays and diagnostic tests can be developed using 2-mercaptopyridine-carbonitriles as SERS reporter molecules.
表面增强拉曼散射（SERS）的高灵敏度和官能团选择性使其成为一种有吸引力的酶传感方法，但目前严重缺乏能够释放具有良好检测特性的SERS报告分子的酶底物。我们发现2-巯基吡啶-3-甲腈（ ）和2-巯基吡啶-5-甲腈（ ）作为SERS报告分子非常有效，它们可以被银或金纳米颗粒捕获，从而产生强烈的SERS光谱，每个光谱在2230 cm处都有一个独特的腈峰。 是一种更灵敏的报告分子，在低纳摩尔浓度下即可检测到。一项分析验证研究合成了两种新型底物分子， 和 ，并表明它们可以被β-葡萄糖苷酶有效切割（ 分别为228和162 μM），β-葡萄糖苷酶是一种具有广泛工业和生物医学用途的酶。此外，对释放的报告分子（ 或 ）进行SERS检测能够传感β-葡萄糖苷酶活性和β-葡萄糖苷酶抑制作用。使用粗杏仁粉提取物进行的对比实验表明，通过SERS检测确认β-葡萄糖苷酶活性的存在比通过紫外可见吸收检测所需的时间短得多（>10倍）。很可能可以使用2-巯基吡啶-腈作为SERS报告分子开发广泛的酶分析和诊断测试。
