Baoli Ou

Reversible fluorescence modulation of spiropyran-functionalized carbon nanoparticles

Fluorescent carbon nanoparticles (CNPs) with diameters of about 3 nm which can emit blue-green light were synthesized through the hydrothermal carbonization of ethylenediaminetetraacetic acid disodium salt (EDTA·2Na). Then, the CNPs were functionalized with spiropyrans to obtain the spiropyran-functionalized CNPs. The emission of the spiropyran-functionalized CNPs centered at 510 nm could be switched off, while being turned on at 650 nm via energy transfer after UV light irradiation. The process could be reversed by using visible light irradiation. The optical switching of the fluorescence was repeated 10 times without apparent “fatigue”, showing excellent photoreversibility and high stability. Spiropyran-functionalized CNPs may find potential applications in biological imaging and labeling, reversible data storage/erasing, as well as individual light-dependent nanoscale devices.

Novel ferrocene-based nanoporous organic polymers for clean energy application

A novel ferrocene-based nanoporous organic polymer (FNOPs-1) for clean energy application has been prepared by coupling 1,1′-ferrocene-dicarboxaldehyde with melamine. The BET surface area and the total pore volume of FNOPs-1 are 752.4 m2 g−1 and 1.32 cm3 g−1, respectively. FNOPs-1 exhibits excellent gas storage capacities such as 16.61 wt% of carbon dioxide, 3.48 wt% of methane, and 1.27 wt% of hydrogen at 273 K/1.0 bar.

Fabrication and Physical Properties of Gelatin/Sodium Alginate/Hyaluronic Acid Composite Wound Dressing Hydrogel

Gelatin (Gel), sodium alginate (SA) and hyaluronic acid (HA) based various hydrogels for biomedical applications were prepared by freezing-drying method using 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) as a crosslinker. The physical properties including morphology, water vapor transmission rate and hydrophilicity were investigated. The result showed the Gel/SA/HA composite hydrogels were successfully crosslinked by the crosslinking agent. All the Gel/SA/HA composite hydrogels with different compositions had highly homogeneous and interconnected pores, and the compositions had no significant effect on the surface and cross-section morphologies of the Gel/SA/HA hydrogels. The incorporation of sodium alginate enhanced the water vapor transmission capacity of the hydrogel; however, there were no significant differences between the water vapor transmission rates of all the Gel/SA/HA hydrogels. Gelatin had a low hydrophilic behavior, while sodium alginate exhibited relatively high hydrophilic behavior. The results indicate that the Gel/SA/HA hydrogel cross-linked via EDC is a potential wound dressing material capable of the adequate provision of moist environment for comfortable wound healing.

Degradation behaviour and biological properties of gelatin/hyaluronic acid composite scaffolds

Abstract Hydrogels, based on natural polymers, are gaining attention as possible cell scaffolding materials for the regeneration of a variety of tissues. In this work, gelatin (Gel) and hyaluronic acid (HA) were used to fabricate novel scaffold materials using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide as a cross-linker. The degradation behaviours of Gel/HA scaffolds in phosphate buffered saline (PBS) and PBS solution containing lysozyme were investigated respectively. The biological properties including haemolytic activity and acute systemic toxicity were also studied. The results showed that the scaffold had an interconnected pore structure with an average pore size of about 100–500 μm. The degradation of Gel/HA scaffolds in PBS solution containing lysozyme was faster than that in PBS solution. The haemolytic ratio of 0·340–0·781% indicated that the Gel/HA scaffolds have a good blood compatibility. The acute systemic toxicity test showed that Gel/HA extracts have no acute systemic toxicity.

Morphological and Functional Expression of Fibroblast on Poly(lactide-co-glycolide)/β-Tricalcium Phosphate/Nature Bone

The in-vitro biocompatibility of degradable and bioactive composites consisting of poly(lactide-co-glycolide) (PLGA), β-tricalcium phosphate (β-TCP), and nature bone (NB) was investigated by culturing fibroblasts on the PLGA/β-TCP/NB substrates, and the cell morphology, proliferation, alkaline phosphatase (ALP) activity, and von Kossa mineralization were evaluated. The results showed that the incorporation of β-TCP and NB benefited fibroblasts attachment and the fibroblasts cultured on the PLGA/β-TCP/NB composite substrates spread better as compared to those on the pure PLGA after culturing for different times. MTT assay showed that the fibroblasts cultured on the PLGA/β-TCP/NB extraction revealed a higher proliferation rate than those on the pure PLGA extraction. ALP and von Kossa assay indicated that β-TCP and NB could promote biomineralization in vitro. All of the results showed that the addition of β-TCP and NB into PLGA could stimulate fibroblasts to proliferate and differentiate.

Mechanical and Antibacterial Properties of Polypropylene/Polyamide 6 Blends-TiO2 Nanocomposites

Polypropylene/Polyamide 6 (PP/PA6) blends-TiO2 nanocomposites have been prepared via melt blending PP/PA6 with TiO2 nanoparticles, which were pretreated with toluene-2,4-di-isocyanate. The functionalized-TiO2 can react with the terminal amino and carboxyl groups at PA6, interfacial interaction and compatibility between TiO2 and matrix have been greatly improved resulted in higher tensile and impact strength than that of those filled with pristine TiO2 or pure PP/PA6 blends, and they have strong antimicrobial abilities against Bacillus subtilis, Staphylococcus aureus and Escherichia coli. The average efficiency of antibacterial is over 90% within 2.0 h. Mechanical and antibacterial properties can achieve their maximum with 3.0 wt%TiO2.

Fabrication and characterisation of gelatin-hyaluronic acid/nanobioactive glass hybrid scaffolds for tissue engineering

Abstract Nanobioactive glass (NBG) particles were synthesised via sol–gel method and characterised by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The new composite biomaterial based on gelatin (Gel) conjugated with hyaluronic acid (HA) and NBG in the ternary SiO2–CaO–P2O5 system was prepared through freeze drying method. The composite scaffold was characterised by using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and thermal analyses. Mechanical properties and swelling behaviour of this composite are compared with properties of Gel-HA/NBG composite of similar material without NBG. The TEM results indicated that the prepared NBG particle size was ∼100 nm. The SEM studies showed that the NBG were homogenously distributed within the Gel/HA matrix and the composite scaffolds showed interconnected pores with a size varied from 50 to 200 μm. The Gel-HA/NBG composite scaffold showed higher compressive strength and better stability than the Gel/HA scaffold. These results indicate that composite scaffolds developed using NBG disseminated Gel/HA matrix as potential scaffolds for tissue engineering applications.

Preparation of Conductive Polyaniline/Functionalized Titanium Dioxide Nanocomposites via Graft Polymerization

Functionalized titanium dioxide nanoparticle (TiO2) with highly reactive isocyanate groups at its surface, which serve as active sites for the graft polymerization of aniline, was prepared via the reaction between toluene-2,4-diisocyanate (TDI) and hydroxyl at TiO2 surface. Conductive polyaniline (PANI) layer was chemically grafted at the surface of the functionalized TiO2 nanoparticle (f-TiO2) surface, resulting in PANI/f-TiO2 nanocomposites. The chemical grafting of PANI was confirmed using FTIR and Thermogravimetric analysis (TGA). The morphology of the PANI/TiO2 nanocomposites was observed by scanning electron microscope (SEM) and transmission electron microscopy (TEM). The amount of grafted PANI is 21 wt%, which was calculated from the results of TGA.

A Novel Route to Prepare Cationic Polystyrene Latex Particles with Monodispersity

Relatively clean cation-charged polystyrene (PS) latex particles were prepared via a novel and simple route in the absence of steric stabilizers. The reaction system only included medium, styrene, and initiator with quaternary ammonium moiety. The influences of initiator concentration, and medium composition on the diameter and size distribution of PS latex particles were systematically investigated. The particle morphology and size, the surface N content, and the particle size distribution were respectively determined by SEM, XPS, and laser particle size analyzer. The results indicated that monodisperse and cation-charged PS latex particles with diameter of 0.45–0.95 μm could be successfully produced via the simple reaction system, and cationic initiator concentration played a key role in the preparation of uniform PS latex particles. Finally, a plausible mechanism was proposed for explaining nucleation, growth, and stabilization of PS latex particles.

Covalent Functionalization of Silica Nanoparticle with Poly(glycidyl methacrylate) via ATRP at Ambient Temperature

The silica nanoparticle was covalently functionalized with toluene-2,4-diisocyanate to prepare the functionalized silica nanoparticle containing isocyanate group. Here, the isocyanate group on the functionalized silica nanoparticle have been further derivatized with water and 2-bromoisobutyryl bromide consecutively resulting in the attachment of atom transfer radical polymerization initiators to the surface of the silica nanoparticle. These silica nanoparticle based macroinitiators were used to initiate polymerization of glycidyl methacrylate at ambient temperature in aqueous media. Thus, structurally well-defined poly(glycidyl methacrylate) was grown from the silica nanoparticle surface to yield individual hybrids composed of a silica core and a well-defined, densely grafted outer poly(glycidyl methacrylate) via atom transfer radical polymerization. FTIR spectroscopy was utilized to follow the covalent functionalization of silica nanoparticle and showed the formation of resulting hybrid particle.