Liguo Sun

Biocompatible core–shell electrospun nanofibers as potential application for chemotherapy against ovary cancer

Polyvinyl alcohol/chitosan (PVA/CS) core-shell nanofibers are successfully fabricated by a simple coaxial electrospinning method, in which PVA forms the core layer and CS forms the shell layer. With the change of the feed ratio between PVA and CS, the surface morphology and the microstructures of the nanofibers are largely changed. The as-prepared core-shell fibers can be used as a carrier for doxorubicin (DOX) delivery. FT-IR analysis demonstrates that hydrogen bond between CS and PVA chains forms. The results of in vitro cytotoxicity test indicate that the core-shell fibers are completely biocompatible and the free DOX shows higher cytotoxicity than the DOX loaded nanofibers. The standing PVA/CS core-shell fibers remarkably promote the attachment, proliferation and spreading of human ovary cancer cells (SKOV3). Via observing by confocal laser scanning microscopy (CLSM), the DOX released from the fibers can be delivered into SKOV3 cell nucleus, which is significant for the future tumor therapy. And, the as-prepared fibers exhibit controlled release for loaded DOX via adjusting the feed ratio between PVA and CS, and the DOX loaded nanofibers are quite effective in prohibiting the SKOV3 ovary cells attachment and proliferation, which are potential for chemotherapy of ovary cancer.

Microfluidic fabrication of magnetic porous multi-walled carbon nanotube beads for oil and organic solvent adsorption

Due to their light weight and recyclable value, carbon nanotube-based materials have been widely used as adsorbents for oils and organic pollutants. The discovery and research of a novel approach to prepare carbon nanotube-based adsorbents with excellent performance is still required urgently. In this paper, we used a modified microfluidic device to construct a kind of three-dimensional (3D) magnetic porous multi-walled carbon nanotube bead and utilized them to adsorb oils and organic solvents floating on or under the water. In the preparation process, acidified multi-walled carbon nanotubes (MCNTs), water-soluble ferroferric oxide nanoparticles (Fe3O4) and water-soluble submicron polystyrene microspheres can improve their dispersion stability and uniformity in microfluidic droplets. In addition, polystyrene microspheres as the hard template can not only supply abundant porous structures but also stabilize the morphology of composite droplets during the solidification. The measurement data indicated that magnetic porous multi-walled carbon nanotube beads (MCNTBs) had adsorption capability (up to 6–18 times their own weight) for oils and organic solvents with 6 times recyclability, and they can serve as a kind of promising adsorbent.

Hollow carbon fiber sponges from crude catkins: an ultralow cost absorbent for oils and organic solvents

In recent years, three-dimensional (3D) carbon-based frameworks have shown great potential as absorbents for oils or organic solvents, but the fabrication of carbon-based materials with low-cost and high-performance is still needed. In this paper, hollow carbon fiber sponges (HCFSs) have been synthesized through the pyrolysis of bulk crude catkins which are ultralow-cost, have a hollow structure and are a carbon-based fibrous material. Owing to their 3D framework and special structure, the HCFSs exhibited a high absorption capacity for organic solvents and oils (55–190 times their own weight) and excellent recyclability. Coupled with the convenient, economical and environmentally-friendly treatment process, HCFSs will be a promising candidate as a kind of absorbent for the removal of pollutants.

Raspberry-like PS/CdTe/Silica Microspheres for Fluorescent Superhydrophobic Materials

Superhydrophobic particulate films were fabricated via deposition of raspberry-like fluorescent PS/CdTe/silica microspheres on clean glass substrates and surface modification. Particularly, the fluorescent microspheres were prepared by a kind of modified strategy, namely introducing poly (acrylic acid)-functionalized polystyrene microspheres and thiol-stabilized CdTe quantum dots into a hydrolysis reaction of tetraethoxysilane simultaneously. And through adjusting the reaction parameters, the polystyrene spheres with two particle sizes and three colors of CdTe quantum dots aqueous solution were obtained. Consequently, raspberry-like microspheres consist of polystyrene cores and the composite shells of CdTe quantum dots and silica. These microspheres possess a fluorescent characteristic and form a hierarchical dual roughness which was conductive to superhydrophobicity, and the hydrophobic tests also showed the contact angles of water droplets on the surface of the raspberry-like microspheres which were over 160° at room temperature.

Magnetic porous graphene/multi-walled carbon nanotube beads from microfluidics: a flexible and robust oil/water separation material

In this paper, magnetic porous graphene/multi-walled carbon nanotube beads (MPGCBs) were fabricated by a modified capillary microfluidic device. Polystyrene (PS) microspheres not only served as the hard templates to form uniform macropores, but were also beneficial for keeping the stability of spherical architecture. In the process of solidification, both graphene oxide (GO) and acidified multi-walled carbon nanotubes (aMWCNTs) enriched with carboxyl functional groups can form stable and uniform dispersion in the droplets. After the calcination treatment, the composite beads had excellent water resistance and robust mechanical properties. Moreover, due to the addition of the Fe3O4 nanoparticles, the beads also possessed the advantage of flexible operation, which can facilitate oriented movement and recycling of the absorbents, and promoted the collection and recovery of the useful pollutants. These multi-functional MPGCBs with interconnected macroporous structures showed high absorption capacity (up to 8–25 times their own weight) for various kinds of oils and organic solvents, relatively high separation efficiency and long-term recycle stability in the oil/water mixture separation process.

High photoelectric PPV/PVA/Ag composite nanofibers by co-electrospinning

Abstract Poly(phenylene vinylene)/polyvinyl alcohol/Ag (PPV/PVA/Ag) composite nanofibers with excellent photoelectric properties were prepared by coaxial electrospinning using PPV/PVA as the shell and Ag nanoparticles (NPs) as the core, Ag NPs aqueous solution was prepared by the reduction method. The results of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that Ag NPs are of a face-centered cubic structure, with an average diameter of 46 nm and the composite nanofibers have uniform and continuous morphology. With increasing Ag content, the diameters of the composite nanofibers decreased from 653 nm to 250 nm. The X-ray diffraction (XRD) patterns verified that in the composite nanofibers, the Ag NPs are not transformed. In the photoluminescence spectra, the PPV/PVA/Ag composite nanofibers presented red-shift compared with PPV/PVA nanofibers. Under illumination, the as-prepared PPV/PVA/Ag composite nanofibers exhibited relatively high photocurrent intensity.