Electrodes modified by a biocomposite film based on silica and gold nanoparticles for the determination of glucose

Composite Silica‐Based Films as Platforms for Electrochemical Sensors

“…To this end, it is promising to introduce on the electrode surface composites made of biosilica films with encapsulated nanomaterials likely to improve the electrical conductivity of the film and/or to act as electrocatalysts. [201] Examples of nanomaterials used for that purpose are: nanostructured carbon, [37,217,224,225] metal nanoparticles, [51,200,212,221,226,227] metal oxide particles,[ 203,213,214 ] or their combination [ 51,219,224 ]. The nanostructured conductive materials can serve as nanoconductors and/or electron mediators between the encapsulated protein and the surface of the electrode, thus increasing the number of electrochemically…”

“…Overall, they contribute at increasing the sensitivity of the analyte determination, enhancing the signal-to-noise ratio, and improving the long-term stability of such biosensors. The co-immobilization of nanoparticles within/on silica biocomposite films on electrodes can be realised in several ways (Figure 6C): (a) one-step modification when all film components are mixed with the silica precursors and applied to the electrode; [77,212,214,226] (b) two-step modification involving the formation of a porous silica layer and its subsequent functionalization with the nano-objects; [136,143,152,218,222] (c) the layer-by-layer (LbL) deposition in which the electrode surface is first coated with a layer of nanoparticles (NP) or nanostructured materials and then covered with the silica biocomposite film. [37,51,213,217,219,224] Hereafter, we will essentially focus on the first (one-step) and the third (LbL) methods mainly used for the construction of enzymatic biosensors while the second one was mainly carried out for the development of the apta-and immunosensors already presented above.…”

“…Gold nanoparticles (Au-NPs) are widely used among the metal nanoparticles for such purpose because of the good affinity to proteins and high electrocatalytic activity. [202,219,224,226] On the basis of an electrogenerated silica film entrapping hemoglobin (Hb) and glucose oxidase (GOx) on carbon and gold electrodes, with or without Au-NPs, it was demonstrated that the stability of the analytical response of the resulting bioelectrodes was significantly improved when Au-NPs (20 nm in diameter) were present. [212,226] Electrochemical biosensing was possible in real media, as pointed out for glucose determination in porcine blood serum using a SiO 2 À HbÀ GOxÀ Au-NPs biocomposite film on a gold electrode.…”

Application of Immobilized Enzymes in Food Industry

“…Second, the amount of reactive Si−OR bonds in alkylalkoxysilane decreases, which also leads to the cross-linking degree reduction. 93 The polycondensation processes of silane precursors tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES) are characterized by high speed under conditions of basic catalysis with sodium fluoride in the presence of PEG in the system. The maximum amount of formed Si−O−Si bonds is observed in the structure obtained with using 50 vol % MTES, because in this case the quantities of the most active nucleophiles (Si(OR) 3 CH 3 ) and the most active substrates (Si(OR) 4 ) are equal.…”

“…First, it occurs due to an increase in the rate of silicon alkoxide precursor hydrolysis with increased number of the methyl groups attached to it. Second, the amount of reactive Si–OR bonds in alkylalkoxysilane decreases, which also leads to the cross-linking degree reduction …”