Xiangxiang Du

Preparation of novel carbon nanofibers with BiOBr and AgBr decoration for the photocatalytic degradation of rhodamine B

Novel carbon nanofibers with BiOBr and AgBr decoration have been prepared by a combination of electrospinning, carbonization and solvothermal treatments. BiOBr/AgBr hybrids interweaved together and covered the carbon nanofibers to form a three-dimensional (3D) open porous structure. The resultant composite carbon nanofibers exhibited a high efficiency for the photocatalytic degradation of RhB in aqueous solution and were convenient to separate from water.

Facile preparation of novel Au–polydopamine nanoparticles modified by 4-mercaptophenylboronic acid for use in a glucose sensor

Au nanoparticles were attached to the surface of polydopamine (PDA) macrospheres by an in situ reduction reaction between PDA and HAuCl4. 4-Mercaptophenyl boronic acid (MPBA) was then modified to form Au–PDA composite particles via a strong Au–S interaction. The resultant MPBA–Au–PDA particles were used in a non-enzyme amperometric glucose sensor.

Boronic acid functionalized N-doped carbon quantum dots as fluorescent probe for selective and sensitive glucose determination

Nitrogen doped carbon quantum dots (NCQDs) of about 10 nm in diameter have been obtained by hydrothermal reaction from collagen. Because of the superiority of water dispersion, low toxicity and ease of functionlization, the NCQDs were designed as a glucose sensor after covalent grafting by 3-aminophenylboronic (APBA) (APBA-NCQDs). The as-prepared APBA-NCQDs were imparted with glucose sensitivity and selectivity from other saccharides via fluorescence (FL) quenching effect at physiological pH and at room temperature, which show high sensitivity and specificity for glucose determination with a wide range from 1 mM to 14 mM. FL quenching mechanism of APBA-NCQDs was also investigated by adding an external quencher. The APBA-NCQDs-based platform is an environmentally friendly way to substitute inorganic quantum dots containing heavy metals which offer a facile and low cost detection method.

Photo-induced synthesis glucose-responsive carriers for controlled release of insulin in vitro

The glucose-responsive amphiphilic poly(PEGMA-co-AAPBA) copolymer micelles as drug carriers have been developed using 3-phenylpyruvic acid (3-PPA) as photoinitiator. Under the light irradiation, 3-PPA could be self-polymerized into the trimer structure to execute the emulsifier and initiator functions that confirmed by gas chromatography-mass spectrum (GC-MS) analysis. The structure and morphology of resultant poly(PEGMA-co-AAPBA) micelles were characterized by 1H NMR and TEM. Insulin, as the model drug of diabetes, was loaded into micelles during the photopolymerization process. The as-prepared polymeric micelles exhibited the excellent glucose sensitivity. The loaded insulin could be released from micelles triggered by regulation of temperature and glucose concentration in the environment. The new drug carriers provided a potential application for the therapy of diabetes based on glucose-sensitive controlled drug delivery systems.

Preparation of glucose-responsive and fluorescent micelles via a combination of RAFT polymerization and chemoenzymatic transesterification for controlled release of insulin

A glucose-responsive and fluorescent copolymer was prepared via a one-pot method that combines RAFT polymerization and enzymatic transesterification. The as-prepared copolymer tended to self-assemble into spherical micelles that were confirmed using 1H NMR, FT-IR and GPC, and transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis. Due to the attachment of fluorescent side groups, the optical properties of the micelles were analyzed using a UV-Vis spectrometer, fluorescence spectrophotometer and confocal laser scanning microscopy (CLSM). Owing to the amphiphilic and glucose-responsive properties, the micelles could be used as carriers for loaded insulin. The insulin release behaviour was evaluated when triggered by glucose in vitro. In addition, the resultant micelles exhibited relatively lower cytotoxicity and excellent stability against a protein solution. The insulin retained its structure stability after release, investigated through circular dichroism (CD) spectra analysis. These results showed that the obtained glucose-responsive and fluorescent polymer micelles with a good biological imaging performance and biocompatibility could be one of the effective candidate carriers for controllable release of insulin.

Preparation of Au/PAN nanofibrous membranes for catalytic reduction of 4-nitrophenol

Due to their high surface energy, naked gold nanoparticles (AuNPs) tend to form agglomerates, which could lead to the decrease of active sites and catalytic activity of AuNPs. Herein, the gold nanoparticles/polyacrylonitrile (AuNPs/PAN) nanofibrous membranes have been prepared via an environmentally friendly and efficient route combining electrospinning, amination, and electroless plating technique. The abundant amine and imine groups can be introduced onto the surface of PAN nanofibrous membranes via amination treatment which could be used as “anchoring sites” to immobilize AuNPs. The resultant composite membranes were applied as the new catalytic materials for reduction of 4-nitrophenol to 4-aminophenol under room temperature. The new catalytic membranes exhibited the significant advantages, such as low dosage, high catalytic activity, easy recycling, and excellent stability.

Facile fabrication of highly flexible graphene paper for photocatalytic reduction of 4-nitrophenol

Freestanding paper-like materials prepared from chemically derived graphene have considerable potential as a carbon-based catalyst in high-performance flexible catalytic reaction. Herein, a highly flexible graphene paper (GP) assembled from graphene oxides (GOs) with the aid of polyacrylamide (PAA) and electroless deposition of gold nanoparticles (AuNPs) was prepared. In contrast to previous reports on GOs based on a flow-directed assembly of graphene sheets, this GOs/PAA/Au composite paper exhibited a highly wrinkled and disordered morphology. The resultant GOs/PAA/Au composite paper was applied as a catalytic material for the reduction of 4-nitrophenol and showed the favour separation, recovery and cyclic utilization properties.

Effects of N and/or S Doping on Structure and Photocatalytic Properties of BiOBr Crystals

The BiOBr crystals doped with N and/or S have been prepared by a facile and rapid solvothermal method using urea and/or thiourea as doped resource. The morphologies and structures of the as-prepared samples were characterized by SEM, TEM, XRD, XPS and PL spectrum. Their electronic structures have been investigated and discussed using first principles based on the density functional theory. The photocatalytic properties of the products can be adjusted by the content and species of dopants.