Electrochemical Study Of Prussian Blue-Based Composite Nanoparticles And Bioelectrical Analysis

In this paper, Prussian blue nanomaterials with electrical activity were synthesized by chemical synthesis and reverse micelle methods. The products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Ultra-visable spectrophotometer (UV-vis) and so on. At the same time, the chemically modified electrodes or enzyme biosensors were prepared by anchoring nanoparticles and glucose oxidase (GOD) onto the surface of electrodes for electrochemical detection. The results showed that the modified electrodes and enzyme biosensors exhibited excellent electrocatalysis for H₂O₂ and glucose. Based on this, an accurate and rapid electroanalytical method for the quantitative analysis of glucose was developed. Compared with others, this method demonstrated high sensitivity, good stability, accurate and reliable results. The research in this work includes the following four components:1,Colloidal dispersions of hybrid nanoparticles composed of Prussian blue (PB) and platinum (Pt) were prepared by adding K₄Fe(CN)₆ and K₂PtCl₆ in turn into PB colloid solution, in which Pt ion and [FeCN₆]^4- in an aqueous solution were reduced and oxidized separately. The formation of hybrid Platinum/Prussian blue (Pt/PB) nanoparticles were characterized by UV-vis and TEM. The diameter of obtained Pt/PB nanoparticles is about 20 nm. The characteristic absorbance peaks of PB nanoparticles at 720 nm could be observed from the Pt/PB colloid. However, the peak magnitude decreases compared with that of PB, which means that Pt covers partly PB nanoparticles. The self-assembled 1, 3-propanedithiol was employed to anchor the metal-modified PB nanoparticles on Au electrodes by the strong metal-sulfur interactions. The study of electrochemical cyclic voltammetry (CV) shows that PB or Pt of Pt/PB is involved in electrochemical catalytically reduction of oxygen.2,The work reports on the characterization, assembly and electroanalytical performance of Prussian Blue/polypyrrole (PBPPy) composite nanoparticles synthesized by reverse micelle method. SEM suggests the formation of nanosized PBPPy particles with the diameter between 40-50 nm. UV-vis spectroscopy and FTIR studies confirm that they are composed of Prussian blue and polypyrrole. PB and PBPPy nanoparticles were anchored onto the surface of cysteine-modified Au electrodes. CV experiments show that PB or PBPPy-modified electrodes exhibit their intrinsic electrochemical properties and high electrocatalytic activity towards H₂O₂. PBPPy-modified electrodes give higher sensitivity to H₂O₂ response than PB-modified electrode. A linear calibration curve over the concentration range 0.99μM～8.26 mM H₂O₂ is obtained with the detection limit of 0.23μM at signal to noise ratio of 3. Excellent stability is observed for PBPPy composite nanoparticle-modified electrodes even in pH 6.0 PBS with high concentration of H₂O₂ (0.99 mM). Glutaraldehyde was employed to immobilize GOD for the development of PBPPy-based biosensors. The results show that PBPPy composite nanoparticles could be used to develop oxidase-based biosensors.3. Prussian blue (PB) nanoparticles were synthesized by employing polymyxin B /sodium bis (2-ethylexyl)sulfosuccinate(AOT)/water/isooctane reverse microemulsion route. FTIR, SEM and electrochemical methods were used to characterize these composite nanoparticles. Also, this paper presents the performance of PB-based glucose biosensors. PB nanoparticles were assembled onto the cysteine-modified Au electrode surface and GOD immobilized by the crosslinking of glutaraldehyde. Both the electrochemical properties of PB and biocatalytical performance of GOD are excellent. Analytical parameters such as reproducibility and stability have been studied and optimized. Also, the glucose biosensors show a wide linear range (6.7μM-2.0 mM) and good reproducibility.4. A square wave voltammetry method was developed for the assessment of organophosphorus (OPs) compound impact on the cholinesterase of pheretima with 2, 6-dichloroindophenol (2, 6-DCIP) as a redox indicator. The substrate of acetylthiocholine is hydrolyzed by the cholinesterase (ChE) from soil animal pheretima, and the produced thiocholine reacts with the 2, 6-DCIP to give obvious shift of electrochemical signal. The inhibition of ChE was assessed by measuring the enzyme activity before and after incubating with parathion-methyl. The reduction peak current of 2, 6-DCIP decreases with the time of enzymatical reaction. The ChE loses almost 32.74 % activity after 10 min incubation with 1 ng/ml parathion-methyl and 54.62 % with 10μg/ml parathion-methyl, while the activity that corresponds to 100μg/ml parathion-methyl was nearly completely inhibited. This method can be employed to assess the inhibition of ChE and investigate OPs impact on environmental animals.