The Role of Peptides in the Design of Electrochemical Biosensors for Clinical Diagnostics.

Patrick Severin Sfragano,Ilaria Palchetti,Giulia Moro,Federico Polo

doi:10.3390/bios11080246

Patrick Severin Sfragano, Ilaria Palchetti + Show 2 more

Open Access

https://doi.org/10.3390/bios11080246

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Abstract

Peptides represent a promising class of biorecognition elements that can be coupled to electrochemical transducers. The benefits lie mainly in their stability and selectivity toward a target analyte. Furthermore, they can be synthesized rather easily and modified with specific functional groups, thus making them suitable for the development of novel architectures for biosensing platforms, as well as alternative labelling tools. Peptides have also been proposed as antibiofouling agents. Indeed, biofouling caused by the accumulation of biomolecules on electrode surfaces is one of the major issues and challenges to be addressed in the practical application of electrochemical biosensors. In this review, we summarise trends from the last three years in the design and development of electrochemical biosensors using synthetic peptides. The different roles of peptides in the design of electrochemical biosensors are described. The main procedures of selection and synthesis are discussed. Selected applications in clinical diagnostics are also described.

Highlights

Peptides are sequences of amino acids of varying length and weight
The study was further extended by designing peptides that could attach to antibodies instead of aptamers and achieve good sensitivity for clinically relevant levels of C-reactive protein (CRP) [16]
A zwitterionic peptide composed of alternating negatively charged glutamic acid (E) and positively charged lysine (K) residues which exhibits antifouling abilities and a well-defined secondary structure for closer packing of the monolayer due to a proline (P) linker peptide (PPPP) was designed by Nowinski et al [49]. These peptide sequences have been proposed in many different Self-assembling peptides (SAPs), obtaining hierarchical assemblies characterized by: an interfacial region that operates as a biomolecular recognition layer or as an enhancer of the target signal [50], an antifouling region that stabilises the selfassembled monolayers (SAMs) via intermolecular interactions, and a surface anchoring portion [49], mainly using a cysteine (C) residue

Summary

Introduction

Peptides are sequences of amino acids of varying length and weight. Only 20 of the hundreds of known amino acids account for the vast majority of residues that make up human proteins [1]. The benefits lie mainly in their stability and selectivity toward a target analyte They can be synthesized rather and modified with specific functional groups, making them suitable for the development of novel architectures for biosensing platforms, as well as alternative labelling tools. Regarding detection, both label and label-free approaches are possible and different electrochemical detection methods are achievable using three main quantities: current (amperometric and voltammetric biosensors), potential, and impedance. The design of the peptide–target characterisation protocol should take into account the final application of the peptide sequence (i.e., the biosensing platform) as the binding performance can vary depending on the physical and chemical properties of the surrounding environment, as recently discussed for other biorecognition elements [32]. The synthesis is coupled with a final purification step, usually performed via reversed-phase high-performance liquid chromatography (RP-HPLC) before checking the molecular mass by mass spectrometry

Peptides as Self-Assembled Layers

Peptides as Antifouling Agents

Peptides as Substrate and Signal Development Agents in Catalytic Biosensors

Peptides as Bioreceptors in Affinity Biosensors

Findings

Conclusions and Outlook