Chitosan (CS) bicomponent nanofibers with an average diameter controlled from 100 to 50 nm were successfully prepared by electrospinning of CS and poly(vinyl alcohol) (PVA) blend solution. Finer fibers and more efficient fiber formations were observed with increased PVA contents. On this contribution, a uniform and ultrafine nanofibrous CS bicomponent mats filled with hydroxyapatite (HA) nanoparticles were successfully electrospun in a well devised condition. An increase in the contents of HA nanoparticles caused the conductivity of the blend solution to increase from 1.06 mS/cm (0 wt % HA) to 2.27 mS/cm (0.5 wt % HA), 2.35 mS/cm (1.0 wt % HA), respectively, and the average diameter of the composite fibers to decrease from 59 ± 10 nm(0 wt % HA) to 49 ± 10 nm (0.5 wt % HA), 46 ± 10 nm (1.0 wt % HA), respectively. SEM images showed that some particles had filled in the nanofibers whereas the others had dispersed on the surface of fibers, and EDXA results indicated that both the nanoparticles filled in the nanofibers and those adhered to the fibers were HA particles. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Cellulose fiber/chitosan biodegradable rod (CF/CS rod) with layer-by-layer structure, good mechanical properties, and excellent X-ray developing capability was successfully constructed via in-situ precipitated method. As the ratio of CF to CS was 0.2/20 (wt/wt), the bending strength and bending modulus arrived at 124.1 MPa and 4.3 GPa, respectively, were significantly improved compared with pure CS rod. TGA indicated that the thermal stability of CS rod could be enhanced by mixing with CF, but fiber and matrix are partially compatible. SEM made clear that fibers were randomly dispersed in the CS matrix to connect layers of CS rod that can endure stress. FTIR spectra illuminated that small amount of Schiff base was formed due to the chemical reaction between fibers and CS matrix, which could enhance the mechanical combining stress of the interface. Thus, CF/CS rod has great potential to be used as internal fixation of bone fracture. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers

Chitosan is an important kind of biomaterial that is widely used in medical applications. One of the key concerns about its use is the preparation of composites used for bone engineering. Aim of this study concerns the preparation of three-dimensional nanocomposites having potential use in bone repair and regeneration. The magnetite/hydroxyapatite/chitosan nanocomposites were prepared via in situ compositing method by preparing precursor solutions and molds with chitosan membrane. These nanocomposites were characterized by chemical, spectroscopic, magnetic, and morphological methods. X-ray diffraction analysis results demonstrate the formation of magnetite and hydroxyapatite in the chitosan matrix. FTIR analysis indicates that inorganic nanoparticles were chemically bound to the amino and hydroxyl groups in CS molecules. From TG/DTA data, it can be concluded that during preparation raw materials were almost perfectly incorporated into the nanocomposites, and the decrease in decomposition temperatures indicates the formation of chemical bonds between inorganic nanoparticles and chitosan molecules. TEM results show that the maximum size of inorganic particles in the magnetite/hydroxyapatite/chitosan nanocomposites was under 50 nm, and these particles were dispersed homogeneously in the chitosan matrix. From the magnetic measurement, it could be concluded that the nanocomposites were superparamagnetic, which is also the peculiarity of nanomagnetites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008