Eryun Yan

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.

Gold nanorods contained polyvinyl alcohol/chitosan nanofiber matrix for cell imaging and drug delivery

Gold nanorods (AuNRs) that contained polyvinyl alcohol/chitosan (PVA/CS) hybrid nanofibers with dual functions are successfully fabricated by a simple electrospinning method. The results of transmission electron microscopy (TEM), X-ray diffraction (XRD) and energy dispersive X-ray (EDX) spectroscopy indicate that AuNRs are indeed encapsulated into the PVA/CS hybrid nanofibers. FTIR spectra results demonstrate that the chemical structures of PVA and CS are not affected when the AuNRs are introduced into the fibers. In vitro cytotoxicity test reveals that the hybrid fibers involving AuNRs are completely biocompatible. The as-prepared fibers can be used as a carrier for anticancer agent doxorubicin (DOX), and the drug is delivered into the cell nucleus. The AuNRs and DOX incorporated fibers are effective for inhibiting the growth and proliferation of ovary cancer cells and they can also be used as the cell imaging agent due to the unique optical properties of AuNRs. The nanofiber matrix combining two functions of cell imaging and drug delivery may be of great application potential in biomedical-related areas.

Preparation and characterization of carboxymethyl chitosan hydrogel

Purpose The purpose of the study reported in this paper was to investigate the process for the preparation of carboxymethyl chitosan (CMCS) hydrogel and to characterize such a hydrogel via various analytical techniques. Design/methodology/approach The hydrogel in the aqueous solution was prepared by using CMCS as the raw material and glutaraldehyde as the crosslinking agent. The as-prepared CMCS hydrogel was characterized by transmission electron microscopy, scanning electron microscopy, Fourier transform infrared (FTIR) spectra, differential scanning calorimetry, X-ray diffraction (XRD) and ultraviolet-visible (UV-vis) spectra. Findings The CMCS hydrogel possessed a porous structure and the shape of the pore was irregular. Generally, the diameter of the pores ranged from 20 to 70 nm. The results from FTIR, UV-vis and XRD showed that there was no obvious difference between the structures of the CMCS hydrogel and CMCS powder. Research limitations/implications The strength of the hydrogel is not high enough and the degree of swelling is relatively small. So, improving the strength and swelling degree of the hydrogel is necessary. Practical implications The CMCS hydrogel presented obvious hollow structures and its fabrication was processed absolutely in aqueous phase. Besides, it possessed low toxicity, good biocompatibility and biodegradability. So, the hydrogel will have potential applications in drug delivery and release, tissue engineering and other biomedical fields. Originality/value This paper is the first to present the relationship between the structures of the CMCS hydrogel and CMCS micromolecule, and it confirms that there is no fundamental difference between them.

Effects of preparation parameters on the morphology of chitosan‐silica hybrid hollow nanospheres

Purpose – The purpose of this paper is to investigate the effects of preparation process and amounts of starting materials on the morphology of chitosan‐silica (CS‐silica) hybrid hollow nanospheres.Design/methodology/approach – A simple method coupling sol‐gel process and in situ self‐assembly was used to prepare CS‐silica nanospheres from the solution containing chitosan‐poly (acrylic acid) (CS‐PAA) nanoparticles, tetraethoxyorthosilicate (TEOS) and polyvinylpyrrolidone (PVP). The morphology of CS‐silica hybrid hollow nanospheres was studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The chemical structures of CS‐PAA nanoparticles and CS‐silica nanospheres were characterised by FT‐IR spectra.Findings – The size and morphology of CS‐silica nanospheres was largely dependent on the starting amounts of TEOS, PVP and ammonia. Moreover, the reaction time can also affect the structures of the hybrid nanospheres.Research limitations/implications – The dispersibility of CS‐s...