Electrochemical investigation on the film of L-cysteine self-assembled to nanoparticles on a gold electrode

The film contained L-cysteine and gold nanoparticles were provided by self-assembled monolayers (SAMs) and potentiostatic electrodeposition technology on the gold electrode. Two methods were used to study the film: In the first, cyclic voltammetry (CV) was used to inspect the functional groups of the film and the same time hydroquinone was chosen to be a probe molecule in the based solution;secondly, based on analytical technology of scanning electrochemical microscopy (SECM), the heterogeneous rate constant (keff) between solid phase (the modified electrode) and liquid phase (K3Fe(CN)6) was obtained. As a result, the better binary catalysis of hydroquinone was demonstrated and the heterogeneous rate constant (keff) is the greater at 8 h for L-cysteine self-assembled monolayers (SAMs).

Balanites aegyptiaca Oil Synthesized Iron Oxide Nanoparticles: Characterization and Antibacterial Activity

Antibacterial activity of iron oxide nanoparticles, an employing B. aegyptiaca oil (L.) Del., was used as natural stabilizer by modifying a co-precipitation method. In this work, we chose B. aegyptiaca oil as the new surfactant coating agent, and synthesized B. aegyptiaca oil coating with iron oxide nanoparticles which were characterized with a variety of methods, including Gas Chromatography (GC) to determine the fatty acids composition of the seeds oil, Fourier Transform-Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM) equipped with Energy Dispersive Spectroscopy (EDS), X-ray Powder Diffractometer (XRD) and Vibrating Sample Magnetometer (VSM). In antibacterial studies, disk diffusion susceptibility test was used to measure efficacy of iron oxide nanoparticles against Gram-positive bacteria Staphylococcus aureus (S. aureus), Bacillus subtilis (B. subtilis) and Gram-negative bacteria Escherichia coli (E. coli) in terms of zone inhibition. The B. aegyptiaca coated on the surface of iron oxide nanoparticles;its particle size was found to be nanoscale below 50 nm, and the magnetization (δs) was 16.975 emu g-1. Antibacterial activity was measured. Efficacy of iron oxide nanoparticles against bacterial strains was found in Escherichia coli (E. coli). All these findings suggest that the nanoparticles synthesized from B. aegyptiaca oil may be a promising reagent for a wide variety of applications in biological fields as well as in nanomedicine.

Synergistic effect enhances the peroxidase-like activity in platinum nanoparticle-supported metal—organic framework hybrid nanozymes for ultrasensitive detection of glucose

The metal—organic frameworks(MOFs)are expected as ideal biomimetic enzymes for colorimetric glucose detection because of their large surface areas,well defined pore structures,tunable chemical composition,and multi-functional sites.However,the intrinsically chemical instability and low mimetic enzyme activity of MOFs hinder the application of them in imitating the enzyme reactions.In this work,we demonstrated a metal-MOF synergistic catalysis strategy,by loading Pt nanoparticles(Pt NPs)on MIL-88B-NH2(Fe-MOF)to increase peroxidase-like activity for the detection of glucose.The induced electrons transfer from Pt atom to Fe atom accelerated the redox cycling of Fe^(3+)/Fe^(2+),improved the overall efficiency of the peroxidase-like reaction,and enabled the efficient and robust colorimetric glucose detection,which was proved by both experiments and density functional theory(DFT)calculation.Additionally,the sensitivity and chemical stability of this synergistic effect strategy to detect the glucose are not affected by the complex external factors,which represented a great potential in fast,easy,sensitive,and specific recognition of clinical diabetes.

Exosome-Coated Zeolitic Imidazolate Framework Nanoparticles for Intracellular Detection of ATP

The intracellular delivery of metal-organic frameworks(MOFs)encapsulated with functional biomolecules represents a promising av-enue in the field of biomedicine and biosensing.To improve the cellular uptake efficiency of MOFs,here we report the fabrication of cancer cell-derived exosome membra ne(EM)-coated zeolitic imidazolate framework-8(EM-ZIF-8)nan oparticles by using a microfluidic son ication device.

A hybrid monolithic column based on flower-shaped zeolitic imidazolate framework for efficient capillary microextraction of brominated flame retardants

A novel flower-shaped zeolitic imidazolate framework(ZIF) doped organic-inorganic hybrid monolithic column(ZIF-HMC) was prepared by a simple sol-gel "one-step" method and utilized for efficient capillary microextraction(CME) of four brominated flame retardants.The prepared monolithic was characterized by Fourier transform infrared,scanning electron microscopy,X-ray photoelectron spectroscopy,energy disperse spectroscopy,and N_(2) adsorption-desorption.The parameters of CME were optimized by orthogonal array design.Under the optimal conditions,the ZIF-HMC showed excellent extraction efficiency,the limit of detection(LODs) and the limit of quantification(LOQs) were in the range of0.52$3.1 mg/L and 1.7$10 mg/L,respectively,and the proposed method demonstrated good recovery(88.8%–116.6%) with the RSD less than 13.6% and a reusability of at least 30 times.The ZIF-HMC possessed great potential for separating organic pollutants and the strategy used here could be extended to prepare other derivatized HMC functionalized monoliths.

Tungsten oxide nanowires and polyaniline hybrid film-based electrochromic device with multicolor display and enhanced capacitance

Electrochromic devices(ECDs)have exhibited promising applications in the fields of energy-saving intelligent buildings and next-generation displays because of their simple structure,low power consumption,and multicolor displays.W_(18)O_(49)/polyaniline(PANI)hybrid films are prepared and assembled to ECDs.Compared with pure PANI and W_(18)O_(49) films,the hybrid film exhibits superior electrochemical and electrochromic performance,including high optical modulation(70.2%),large areal capacity(79.6 mF/cm^(2)),and good capacitance retention.The excellent electrochemical and electrochromic performance is ascribed to the formation of the donor(PANI)-acceptor(W_(18)O_(49))pair,the porous structure in the nanowires,and the large surface area,which enhance electron delocalization of the W_(18)O_(49)/PANI,improve the ion diffusion rate,and increase the charge storage sites.Furthermore,benefitting from the outstanding optical,electrical,and multifunctional properties,the W_(18)O_(49)/PANI hybrid film-based ECD platform is expected to play an important role in electrochromism and energy storage.

A co-activation strategy for enhancing the performance of hematite in photoelectrochemical water oxidation

Hematite(α-Fe_(2)O_(3))is a promising photoanode for photoelectrochemical(PEC)water splitting.However,the severe charge recombination and sluggish water oxidation kinetics extremely limit its use in photohydrogen conversion.Herein,a co-activation strategy is proposed,namely through phosphorus(P)doping and the loading of CoAl-layered double hydroxides(CoAl-LDHs)cocatalysts.Unexpectedly,the integrated system,CoAl-LDHs/P-Fe_(2)O_(3) photoanode,exhibits an outstanding photocurrent density of 1.56 mA/cm^(2) at 1.23 V(vs.reversible hydrogen electrode,RHE),under AM 1.5 G,which is 2.6 times of pureα-Fe_(2)O_(3).Systematic studies reveal that the remarkable PEC performance is attributed to accelerated surface OER kinetics and enhanced carrier separation efficiency.This work provides a feasible strategy to enhance the PEC performance of hematite photoanodes.