. MWCNTs were oxidized making use of nitric acid to yield fCNT with hydroxyl. MWCNTs

. MWCNTs were oxidized making use of nitric acid to yield fCNT with hydroxyl
. MWCNTs had been oxidized utilizing nitric acid to yield fCNT with hydroxyl groups. Then, a bionanocomposite was prepared by dispersing the fCNTs inside a chitosan resolution, which was deposited around the electrode surface to conduct electrochemical measurements. The linear detection array of the created electrochemical sensor system was 0.050 , as well as the LOD was 30 nM for Epn detection [108]. In 2018, Sobhan et al. developed a biosensor based on SWCNTs by utilizing linear sweep voltammetry (LSV) measurements to detect the protein Ara h1, which induces peanut allergy. Within this regard, 1-pyrenebutanoic acid succinimidyl ester (1-PBSE) was used to hyperlink the SWCNTs and Ara h1 antibody by means of noncovalent bonding (- stacking interactions). The linear detection range of the created biosensor was 1.000 ng mL-1 , along with the LOD was 1 ng mL-1 for protein Ara h1 detection [109]. The following year, Dudina and coworkers created a Cysteinylglycine Endogenous Metabolite monolithic biosensor platform by using carbonnanotube field-effect transistors (CNTFETs) for glutamate determination. The CNTFETs had been functionalized with glutamate oxidase by way of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysulfo-succinimide (sulfo-NHS). The developed biosensor showed a detection range involving 250 and 500 , and also the LOD was ten [110]. In 2020, Palomar and coworkers prepared an electrochemical sensor depending on peptidemodified AuNP/CNTs to detect a proteolytic enzyme named matrix metalloproteinase-7 (MMP-7). This enzyme is overexpressed in cancer and cardiovascular diseases. Enzy-Nanomaterials 2021, 11,9 ofmatic cleavage of peptides immobilized around the nanocomposite-modified electrode surface was carried out to raise the system’s Isoprothiolane supplier stability. The linear detection array of the developed biosensor was 1 10-2 -1 103 ng mL-1 , along with the LOD was 6 pg mL-1 [111]. Not too long ago, Silva and coworkers developed a label- and probe-free immunosensor based on Prussian blue@carbon nanotube olypyrrole (PB@CNT Py) nanocomposite for the determination of the NS2B protein of Zika virus (ZIKV) by using an amperometric approach. Modification of a carbon nanotube olypyrrole composite with Prussian blue (PB) triggered redox catalytic activity. Thus, electrochemical analysis was performed with out adding any redox probe resolution towards the medium (probe-free detection). Covalent immobilization antiNS2B was carried out through EDC/NHS chemistry on the screen-printed electrode (SPCE). This sensor had the benefit of using a point-of-care diagnosis. Excellent selectivity was obtained among unfavorable and constructive ZIKV serum applying this immunosensor (Figure three) [85].Figure three. Schematic representation of ZIKV immunosensor. (a) Electrode preparation stage and (b) principle of analytical measurement. Reprinted with permission from ref. [112].Nanomaterials 2021, 11,ten of3.two.two. Graphene-Based Nanomaterials Graphene (GR) is usually a two-dimensional (2D) carbon nanomaterial with a single atomic layer of sp2 carbon atoms arranged within a honeycomb lattice. Owing to its higher surface area and higher electrical conductivity, it includes a higher potential to become the world’s thinnest electrode material employed in electrochemical applications. Additionally, GR, with its comprehensive -electron technique, has a sturdy affinity for carbon-based cyclic structures located in drugs, pollutants, and biomolecules. GR has a particular surface location of 2630 m2 g-1 , bigger than that of CNTs (1315 m2 g-1 ) and raw graphite (ten m2 g-1 ) [113]. In addition, the electrical conductivity of GR is 60 times highe.