São Carlos Institute of Physics, University of São Paulo, 13566-590 São Carlos - SP, Brazil.
São Carlos Institute of Physics, University of São Paulo, 13566-590 São Carlos - SP, Brazil; Nanotechnology National Laboratory for Agriculture (LNNA), Embrapa Instrumentação, 13560-970 São Carlos - SP, Brazil.
Bioelectrochemistry. 2021 Apr;138:107692. doi: 10.1016/j.bioelechem.2020.107692. Epub 2020 Nov 21.
Peptides with an active redox molecule are incorporated into nanostructured films for electrochemical biosensors with stable and controllable physicochemical properties. In this study, we synthesized three ferrocene (Fc)-containing peptides with the sequence Fc-Glu-(Ala)-Cys-NH, which could form self-assembled monolayers on gold and be attached to antibodies. The peptide with two alanines (n = 2) yielded the immunosensor with the highest performance in detecting C-reactive protein (CRP), a biomarker of inflammation. Using electrochemical impedance-derived capacitive spectroscopy, the limit of detection was 240 pM with a dynamic range that included clinically relevant CRP concentrations. With a combination of electrochemical methods and polarization-modulated infrared reflection-absorption spectroscopy, we identified the chemical groups involved in the antibody-CRP interaction, and were able to relate the highest performance for the peptide with n = 2 to chain length and efficient packing in the organized films. These strategies to design peptides and methods to fabricate the immunosensors are generic, and can be applied to other types of biosensors, including in low cost platforms for point-of-care diagnostics.
具有活性氧化还原分子的肽被整合到纳米结构薄膜中，用于具有稳定和可控物理化学性质的电化学生物传感器。在这项研究中，我们合成了三种含有二茂铁（Fc）的肽，序列为 Fc-Glu-（Ala）-Cys-NH，它们可以在金上自组装成单层，并与抗体结合。具有两个丙氨酸（n=2）的肽在检测 C 反应蛋白（CRP）方面表现出最佳性能，CRP 是炎症的生物标志物。使用电化学阻抗衍生的电容光谱法，检测 CRP 的检出限为 240 pM，动态范围包括临床相关的 CRP 浓度。通过电化学方法和偏振调制红外反射吸收光谱的组合，我们确定了参与抗体-CRP 相互作用的化学基团，并能够将 n=2 的肽的最佳性能与链长和有序薄膜中的有效组装联系起来。这些设计肽的策略和制备免疫传感器的方法是通用的，可以应用于其他类型的生物传感器，包括用于即时诊断的低成本平台。
