Peptide-based electrochemical biosensors for use in testing for anti-SARs-CoV-2

• Grant number: 23/13068-4
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Effective date (Start): November 01, 2023
• Effective date (End): April 30, 2025
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Acordo de Cooperação: CNPq - INCTs
• Principal Investigator: Wendel Andrade Alves
• Grantee: Anderson Ferreira Sepulveda
• Host Institution: Centro de Ciências Naturais e Humanas (CCNH). Universidade Federal do ABC (UFABC). Ministério da Educação (Brasil). Santo André , SP, Brazil
• Associated research grant: 14/50867-3 - INCT 2014: National Institute of Science and Technology in Bioanalysis, AP.TEM

Abstract

To combat infectious diseases as well as monitor the extent of these diseases, the field of detection has focused on the creation, understanding and application of electrochemical biosensors, which are due to the simplicity of construction, are fast, accessible, portable and allow testing at the point of care (POC). However, we still face considerable limitations such as: price, sensitivity and stability. Making clear the need for scalable, field-deployable and affordable technologies. When it comes to COVID-19, the Spike (S) protein is one of the elements that can be used as a biorecognition agent in the construction of biosensors. The group of Prof. Alves has advanced studies on this biomolecule and on immunogenic peptides derived from it. In one of their collaborations, they built an electrochemical device based on pyrolyzed carbon electrodes modified with surfactant, gold nanoparticles (AuNPs) and protein S. Due to the high surface area and biocompatibility, studies demonstrate that the platform is efficient in immobilizing the protein S and to recognize anti-SARs-CoV-2 antibodies in complex samples without suffering from the effect of biofouling. Despite the advantages, the device is rarely applied in everyday situations due to low stability, unsatisfactory sensitivity, high cost, complexity and distribution of protein S. An alternative that has been studied is the development of detection kits using mimetic components as a recognition element.1 In another study, they described a "label-free" electrochemical biosensor, built on glassy carbon electrodes/AuNPs functionalized with a peptide (P) sequence, mimetic of protein S, for monitoring Anti-SARs-CoV-2 antibodies in serum of convalescent patients. ELISA and molecular docking studies demonstrate that P interacts with specificity with COVID-19 IgG antibodies. In addition to presenting a better performance when compared to protein S, suggesting that the decrease of the receptor in relation to the target helps in sensitivity and specificity.2 However, this P is located in a region outside the receptor binding domain (RBD), which is a region of great interest, which due to mutations gave rise to new variants. Thus, new peptides need to be studied to efficiently meet the constant changes. Recent surface-amplified Raman spectroscopy (SERS) and electrochemical data obtained by Prof. Alves at UFABC has shown that peptides derived from P44 located in the RBD (hotspot region) have great potential as a biorecognition element in the development of biosensors.3 Inspired by the data obtained by the group, as well as the satisfactory results obtained by the electrochemical platforms modified with AuNPs and peptide, we will produce and study three immunogenic peptide sequences present in RBD, in order to promote a systematic study of analysis of the influence of molecular alterations in the morphology of the nanostructures formed with different degrees of molecular density as well as their correlation to the detection of Anti-SARS-CoV-2 antibodies in the construction of biosensors. Additionally, we will use Machine Learning methods (neural networks) to optimize the optimization parameters of the modified electrodes, aiming at transposing the bench to the real world. (1)Nicoliche, C. Y. N. et al. ACS Appl Mater Interfaces 2022. DOI: 10.1021/acsami.1c18778 (2) Castro, A. C. H. et al. ACS Nano 2022. DOI: 10.1021/acsnano.2c04364. (3) Oliveira, J. R. et al. Front Immunol 2022, 13, 1010105. DOI: 10.3389/fimmu.2022.1010105.