Genetically Engineered Phage-Templated MnO₂ Nanowires: Synthesis and Their Application in Electrochemical Glucose Biosensor Operated at Neutral pH Condition

Abstract

To conveniently obtain one-dimensional MnO2 nanowires (NWs) with controlled structure and unique properties for electron transfer, the genetically engineered M13 phages were used as templates for precise nucleation and growth of MnO2 crystals in filamentous phage scaffolds, via the spontaneous oxidation of Mn(2+) in alkaline solution. It was found that the morphology of NWs could be tailored by the surface charge of M13 mutants. MnO2 crystals were uniformly distributed on the surface of negatively charged tetraglutamate-fused phage (M13-E4), significantly different from irregular MnO2 agglomeration on the weakly negatively charged wild-type phage and positively charged tetraarginine-fused phage. The as-synthesized M13-E4@MnO2 NWs could catalyze the electro-oxidation of H2O2 at neutral pH. To demonstrate the superiority of the electrocatalytic activity in the solution containing plenty of chloride ions at neutral pH, both glucose oxidase and as-prepared MnO2 NWs were used for fabricating the glucose biosensor. The proposed biosensor showed a wide linear range (5 μM to 2 mM glucose), a low limit of detection of 1.8 μM glucose (S/N = 3), good interassay and intra-assay reproducibility and satisfactory storage stability. Due to the superiorities of synthesis and electrochemical performance, the as-prepared MnO2 NWs are promising for applications in electrocatalysis, electrochemical sensor, and supercapacitor.

Rectangular flake-like mesoporous NiCo2O4 as enzyme mimic for glucose biosensing and biofuel cell

“…Generally, glucose biosensors and GBFCs can be classified into two categories according to the types of catalysts, namely enzymebased and nonenzyme-based ones [2][3][4]. Research findings demonstrate that enzymatic catalysts exhibit high activity and excellent selectivity, but the unstable operating environment and fragile stability greatly hinder their practical applications [5,6]. To overcome these drawbacks, non-enzymatic catalysts (such as precious metal nanoparticles or alloys [7][8][9][10], composite materials [11,12], polymers [13,14] and transition metal oxides [15][16][17][18]) as enzyme mimics show higher performance than enzymatic ones.…”

Organic Templates for Inorganic Nanocrystal Growth

“…[108,[145][146][147] M13 bacteriophage (6.6 9 880 nm) was first studied as a template for synthesizing single-crystal semiconductor (i.e., ZnS and CdS) and magnetic (i.e., CoPt and FePt) nanowires (Figure 6a). [108,[145][146][147] M13 bacteriophage (6.6 9 880 nm) was first studied as a template for synthesizing single-crystal semiconductor (i.e., ZnS and CdS) and magnetic (i.e., CoPt and FePt) nanowires (Figure 6a).…”

“…In addition to spherical viruses, two rod-like viruses, bacteriophage M13 and tobacco mosaic virus (TMV), can serve as anisotropic biotemplates for the synthesis of inorganic nanorods of uniform length and width. [108,[145][146][147] M13 bacteriophage (6.6 9 880 nm) was first studied as a template for synthesizing single-crystal semiconductor (i.e., ZnS and CdS) and magnetic (i.e., CoPt and FePt) nanowires (Figure 6a). [148,149] Subsequently, gold-cobalt oxide nanowires were also made by incorporating gold-binding peptides into the capsids.…”

Nitrogen‐doped Hollow Co3O4 Nanofibers for both Solid‐state pH Sensing and Improved Non‐enzymatic Glucose Sensing

“…Alternatively, non‐enzymatic glucose test strips, typically operating in alkaline environment, are proposed and developed to address aforementioned challenges. Up to date, various kinds of metal oxides have been exploited in this regard, including CuO , NiO , , Co 3 O 4 , MnO 2 , Mn 3 O 4 , Fe 3 O 4 , , IrO 2 , Rh 2 O 3 , SnO 2 , TiO 2 etc. Compared to noble metal or noble metal alloy, metal oxides based non‐enzymatic glucose detection is free of chloride fouling at high chloride concentration, which is commonly encountered in blood sample test.…”