Nanoparticle‐Based Electrochemical Bioassays of Proteins

Abstract

This article reviews a variety of new nanoparticle/biomolecule assemblies for advanced electrical detection of proteins. Effective methods for the reliable and trace measurements of proteins are highly desired for facilitating the diagnosis of disease states and improving drug discovery. Ultrasensitive monitoring of biomolecular interactions of proteins is particularly challenging owing to the absence of PCR-like amplification protocols and their greater nonspecific binding to solid supports compared to oligonucleotides. Recent activity has led to innovative and powerful nanoparticle-based immunoassays and aptamer bioassays of proteins based on a variety of electrochemical detection schemes. The enormous signal enhancement associated with the use of nanoparticle amplifying labels and with the formation of nanoparticle-protein assemblies provides the basis for ultrasensitive electrochemical detection of proteins. Such protocols rely on the use of colloidal gold tags, semiconductor (quantum dot) tracers, carrier (amplification) nanomaterials, or magnetic (separation) beads, in connection to electrochemical stripping measurement of the metal tag. Remarkable PCR-like sensitivity has been achieved by coupling particle-based amplification units and various amplification processes. The use of nanocrystal tracers for designing electrochemical coding protocols for detecting multiple proteins will also be documented.

Carbon Nanomaterials in Biosensors: Should You Use Nanotubes or Graphene?

“…This significance arises as nanomaterials can help address some of the key issues in the development of all biosensors. Such issues include: design of the biosensing interface so that the analyte selectively interacts with the biosensing surface; [9,10] achievement of efficient transduction of the biorecognition event; [11,12] increases in the sensitivity and selectivity of the biosensor; [13,14] and improvement of response times in very sensitive systems. [15] More specific challenges include: making biosensors compatible with biological matrices, so that they can be used in complex biological samples or even in vivo; [16,17] fabrication of viable biosensors that can operate within confined environments such as inside cells; [17] and multiplexing biosensors so multiple analytes can be detected on one device.…”

Aptasensors Based on Stripping Voltammetry

“…In these cases, the nanomaterials bound to the target or probe or electrode are first dissolved in acid solutions (such as HNO 3 and HCl) to release ions (such as Ag + , Pb 2+ , Cd 2+ , Cu 2+ ) which are, afterwards, detected by stripping voltammetry. The roles of the nanomaterial are: (i) to give electrochemical signals by stripping analysis of the dissolved metals; (ii) to modify the surface of the electrode for making much sensitive electrochemical transducers; and (iii) to immobilize capturing probes [50]. Nowadays, mercury-based electrodes are scarcely used since Hg is recognized as a toxic material.…”

“…In bioassays, antibodies have been widely used in the analysis of clinical biofluid specimen, such as urine and blood [50,65,66]. However, antibodies are not stable and may lose activity easily.…”

Double‐Layer Nanogold and Poly(amidoamine) Dendrimer‐ Functionalized PVC Membrane Electrode for Enhanced Electrochemical Immunoassay of Total Prostate Specific Antigen

“…Recently, protein-mediated assembly of nanoparticles is a potent tool for the creation of new materials [19]. These materials combine tunable nanoparticle features (size, surface functionality, and core properties) with the unique physical and chemical properties of proteins and peptides [20].…”