betadex and ferric-ferrocyanide

This work reports a novel, ultrasensitive, and selective sensing platform based on a direct electrodeposition of electrochemical reduced graphene oxide (ERGO)-Au nanoparticles (AuNPs)-β-cyclodextrin (β-CD) and Prussian blue-chitosan (PB-CS) on glass carbon electrode (GCE) for efficiently fixed acetylcholinesterase (AChE) to fabricate organophosphorus pesticides (OPs) biosensor. The PB-CS not only effectively catalyzed the oxidation of thiocholine (TCh), but also shifted its oxidation potential from 0.68 to 0.2V, and accordingly the sensitivity of the biosensor was obviously improved. The synergistic effect between ERGO and AuNPs significantly promoted the electron transfer between PB and GCE, and remarkably enhanced the electrochemical oxidation of TCh. Besides, β-CD could interact with substrate by reversible bonding, which is contribute to increase the enrichment of the substrate and improve the selectivity and sensitivity of the biosensor. The integration of ERGO-AuNPs-β-CD with PB-CS provided an advantageous and high-performance platform for sensing applications. Based on the inhibition of OPs on AChE activity, the sensor showed wide linear ranges of 7.98-2.00×10(3)pgmL(-1) and 4.3-1.00×10(3)pgmL(-1) with low detection limits of 4.14pgmL(-1) and 1.15pgmL(-1) for malathion and carbaryl, respectively. The proposed biosensor exhibited short response time, good stability and high sensitivity, which can be used for direct analysis of practical samples.

Topics: Acetylcholinesterase; beta-Cyclodextrins; Biosensing Techniques; Chitosan; Ferrocyanides; Gold; Graphite; Limit of Detection; Nanocomposites; Organophosphorus Compounds; Oxidation-Reduction; Pesticides; Vegetables

One-pot green approach to the synthesis of Prussian blue nanocubes/reduced graphene oxide (PBNCs/RGO) nanocomposite had been attempted. It was based on the extract of mushroom with K3[Fe(CN)6] and graphene oxide (GO) as precursors, where the reduction of GO and the deposition of PBNCs occurred simultaneously. The obtained nanocomposite was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy and electrochemical techniques. With the introduction of β-cyclodextrin (β-CD), the β-CD/PBNCs/RGO system showed linear behavior in the range from 0.01 to 700 μM for 4-nitrophenol with a low detection limit of 2.34 nM (S/N=3).

Topics: Agaricales; beta-Cyclodextrins; Electrochemical Techniques; Ferrocyanides; Graphite; Microscopy, Electron, Transmission; Nanocomposites; Nanotubes; Nitrophenols; Oxidation-Reduction; Oxides; Spectrum Analysis, Raman; Water

Control of molecular and supramolecular properties is used to obtain a new advanced hybrid material based on Prussian blue nanoparticles (PB NPs). This hybrid material is obtained through a self-assembled Layer-by-Layer (LbL) approach combining the advantageous features of β-cyclodextrin (β-CD) polysaccharides, PB NPs and poly(allylamine hydrochloride) from electrostatic interaction between the deposited layers. Transmission electronic microscopy images suggested that PB NPs were protected by β-CD polysaccharides that prevent the aggregation phenomena. In addition, as confirmed by scanning electronic microscopy images, it was found that PB NPs are organized in microcubic supramolecular like structures via a mesoscale self-assembly process. Interestingly, the 3-bilayer {PAH/PB-CD} film exhibited a higher density of microcubic structures and a high electrochemical response with PB sites available for redox reactions at a supramolecular level. By utilizing fewer bilayers and consequently less material deposition, the formed {PAH/PB-CD} multilayer films of a tuneable conductivity can be expected to have interesting future applications for host-guest like dependent electrochemical biosensing designs.

Topics: beta-Cyclodextrins; Biosensing Techniques; Electrochemical Techniques; Electrodes; Ferrocyanides; Nanoparticles; Polyamines; Static Electricity