Substrate Materials for Biomolecular Immobilization within Electrochemical Biosensors

Abstract

Electrochemical biosensors have potential applications for agriculture, food safety, environmental monitoring, sports medicine, biomedicine, and other fields. One of the primary challenges in this field is the immobilization of biomolecular probes atop a solid substrate material with adequate stability, storage lifetime, and reproducibility. This review summarizes the current state of the art for covalent bonding of biomolecules onto solid substrate materials. Early research focused on the use of Au electrodes, with immobilization of biomolecules through ω-functionalized Au-thiol self-assembled monolayers (SAMs), but stability is usually inadequate due to the weak Au–S bond strength. Other noble substrates such as C, Pt, and Si have also been studied. While their nobility has the advantage of ensuring biocompatibility, it also has the disadvantage of making them relatively unreactive towards covalent bond formation. With the exception of Sn-doped In2O3 (indium tin oxide, ITO), most metal oxides are not electrically conductive enough for use within electrochemical biosensors. Recent research has focused on transition metal dichalcogenides (TMDs) such as MoS2 and on electrically conductive polymers such as polyaniline, polypyrrole, and polythiophene. In addition, the deposition of functionalized thin films from aryldiazonium cations has attracted significant attention as a substrate-independent method for biofunctionalization.

Use of Cysteamine and Glutaraldehyde Chemicals for Robust Functionalization of Substrates with Protein Biomarkers—An Overview on the Construction of Biosensors with Different Transductions

“…To date, very few studies have been reported on the clinical simultaneous multiplexed biosensing of multiple biomarkers in large (mL) or tiny (µL) [ 47 ] volumes using point-of-care conditions. Fortunately, there are several studies on the preparation of substrates for microarray protein chips with different ending functional groups [ 69 ], on the orientation and characterization of immobilized antibodies [ 70 , 71 ], on the proteins/peptides modified hydrogels [ 72 ], and on the stability of long SAM layers [ 73 ] to greatly support the next generation of point-of-care portable bio devices [ 74 ].…”

Hybrid Nanobioengineered Nanomaterial-Based Electrochemical Biosensors

“…Proteins are responsible for many biological processes in cells and tissues, but any failure in their normal function may result in a type of pathology such as cancer considering them as appropriate biomarkers. For sensing proteins involved in cancer, Zhou et al proposed an electrochemical immunosensor based on a primary antibody (Ab1) adsorbed on top of AuNPs electroplated at the surface of a GCE and a hydroxyl pillar [5]arene (HP5)@AuNPs@g-C 3 N 4 (HP5@AuNPs@g-C 3 N 4 ) hybrid nanomaterial bioconjugated with a secondary prostate-specific antigen (PSA) antibody (Ab2). The immunosensor was tested with different PSA target concentrations by DPV, having a linear response from 0.0005-10.00 ng/mL and a LOD of 0.12 pg/mL [117].…”

“…Electrochemical nanobiosensors are devices designed as alternatives to conventional laboratory-based detection techniques for disease diagnosis due to their robustness, small size, user-friendly operation, amenability for miniaturization, and potential for personalized diagnosis [4][5][6]. Electrochemical nanobiosensors comprise electroactive transducer platforms that anchor specific and selective bioreceptors, generating a nanobioconjugate.…”

“…-C 3 N 4 /Ag hybrids TEM, XPS, XRD, AFM, EIS, CV, and DPV 1.00 × 10 −6 to 1.50 × 10 −4 mol/L with a LOD of 1.40 × 10 −7 mol/L[167] PSA, prostate-specific antigen; HER2, human epidermal growth factor receptor 2; AXL, tyrosine kinase; CaMV35S, cauliflower mosaic virus 35S; SAMs, self-assembled monolayers; MIPs, molecular imprinted polymers; miRNA, micro-ribonucleic acid; CA19-9, carbohydrate antigen 19-9; CA125, carbohydrate antigen 125; NMP-22, nuclear matrix protein-22; PKA, protein kinase A; CK2, casein kinase II; PAD, paper-based analytical devices; OVA, ovalbumin; CEA, carcinoembryonic antigen; NHE, human neutrophil elastase; NSE, neuron-specific enolase. b HP5, hydroxylpillar[5]arene; AuNPs, gold nanoparticles; Ab, antibody; Gox, glucose oxidase; PANI, polyaniline; Cys, cysteine; MOFs, metal-organic framework; fGQDs, functionalized graphene quantum dots; anti-Dig-HRP, antibody-digoxigenin-horseradish peroxidase; ssDNA, single-strand DNA; MWCNT, multiwalled carbon nanotube; CNT, carbon nanotube; PEI, polyethyleneimine; GCE, glassy carbon electrode; SPAuE, screen-printed gold electrode; MNPs, metallic nanoparticles; Fc, ferrocene; MPBA, 4-mercaptophenylboronic acid; QD, quantum dots; ITO, indium tin oxide; DSN, duplex-specific nuclease; PET, polyethylene terephthalate; GO, graphene oxide; PVA, poly(vinyl alcohol); GS, graphene sheet; GNR, graphene-gold nanorod; rGO, reduced graphene oxide; UT, ultrathin; PEG, polyethylene glycol; MB, methylene blue; THI, electron-mediating thionin; PB, Prussian blue; PEDOT, poly(3,4-ethylenedioxythiophene), SPCE, screen-printed carbon electrode; MSF, mesoporous silica thin film; PNE, polynorepinephrine; IL, ionic liquid; ERGO, electrochemically reduced graphene. c CV, cyclic voltammetry; EIS, electrochemical impedance spectroscopy; DPV, differential pulse voltammetry; XRD, X-ray diffraction; XPS, X-ray photoelectron spectroscopy; FTIR, infrared spectroscopy; UV-Vis, ultraviolet visible spectroscopy; SEM, scanning electron microscopy; TEM, transmission electron microscopy; SWV, square wave voltammetry.…”

Bioactive Coatings on Titanium: A Review on Hydroxylation, Self-Assembled Monolayers (SAMs) and Surface Modification Strategies

“…The properties of the solid surfaces, including their physical, chemical, electric, bioactivity and optical properties can be modulated by incorporating the specific terminal end group of the SAMs [ 70 ]. Consequently, this type of surfaces has shown wide applicability in very different fields such as molecular sensors [ 71 ], electrochemical sensing [ 72 , 73 ] biosensors [ 74 , 75 ], preventive anti-biofouling surfaces [ 76 ], organic electronics [ 77 , 78 ] and tribological applications [ 79 ], among others.…”