Preparation and Characterization of Magnetic Chitosan Microcapsules

Abstract

By dispersing aqueous precipitant in liquid paraffin to prepare a W/O emulsion then adding chitosan (CS) solution, CS microcapsules have been successfully prepared. It is a facile way to prepare polymer microcapsules by using aqueous precipitant or nonsolvent as template, which avoids the removal of template and would free from the necessity to cross-link the microcapsule as usual methods to directly form dense shell. The hollow feature of the obtained materials is revealed. The diameter of the microcapsules ranges from severalμm to over 100 μm. Magnetic CS microcapsules have been prepared in this way when Fe3+and Fe2+were mixed with CS to prepare a mixture starting solution. The appearance and microstructure of the composite microcapsules were studied. The results indicate that the formed Fe3O4nanoparticles are embedded in the CS matrix evenly due to strong interaction between the Fe3O4nanoparticles and the CS molecules. The Fe3O4content and the magnetic properties of the composite microcapsule were measured. The composite microcapsules were calcined in air at 700°C to prepare pure inorganic hollow microspheres. It is general to prepare hollow polymeric or composite particles by using this method.

Fabrication of Bilayer Coating of Poly(3,4-ethylenedioxythiophene)-Halloysite/Chitosan and Mg2+/Sr2+-Doped HAP on Titanium Alloy for Biomedical Implant Applications: Physicochemical and In Vitro Biological Performances Studies

“…09-432) and our previous studies [7], the so-obtained MHA diffractogram indicates a poorly crystalline, nonstoichiometric form due to mineral ions substituted in MHA crystal sites. e CS composite was in a crystalline state with two main diffraction peaks at about 11.6°and 20.2°, which was coated on the alkali-treated Ti alloy substrate (Figure 3(c)) [15].…”

“…e most characteristic bands of CS were visible at 1650 cm −1 and 1554 cm −1 , which were assigned to the amide bond of CO-NHR, and the protonated amine groups of NH 3 + are deformation vibrations, while the band located at 1385 cm −1 correspond to the C-H bonds on the CS. Also, the presence of bands in the range of 1136 cm −1 can be assigned to the C-O stretching vibrations in the CS chain [15]. According to the FTIR results shown in Figure 2(c), the position and the intensity of PEDOT-HNT peaks change in PEDOT-HNT/CS-HA coating and shifted to lower wavenumbers [15].…”

“…Also, the presence of bands in the range of 1136 cm −1 can be assigned to the C-O stretching vibrations in the CS chain [15]. According to the FTIR results shown in Figure 2(c), the position and the intensity of PEDOT-HNT peaks change in PEDOT-HNT/CS-HA coating and shifted to lower wavenumbers [15].…”

“…Similarly, chitosan (CS) is an interesting biopolymer, which has good antimicrobial, biocompatible, and biodegradable features [15] due to its excellent film-forming properties and is easy for functionalization. Recently, CS has been extensively used for a number of applications such as cosmetic and metal-based biomaterials which are applied to bone grafts and scaffolds for tissue engineering.…”

Physicochemical characterization of drug nanocarriers

“…The use of wet SEM is, as yet, mainly restricted to the characterization of microspheres and microcapsules, 31 while cryo-SEM has been used for the characterization of microspheres 32 and nanoemulsions. 33 The main limitation of SEM is the resolution of the images, which restricts its application to samples ~200 nm in size.…”