STUDY OF CHITOSAN COATINGS ON NANOPARTICLES FOR BIOMEDICAL APPLICATIONS

Of late, much work and interest had been generated in the fields involving nanoparticles. Due to their nanometer scale, these particles have been proven to be promising in diverse applications such as electronics and medicine, amongst others. In addition, an emerging and attractive use of nanoparticles as biotherapeutic delivery agents within the body was introduced. However, in order to use these nanoparticles in any biomedical application, they must be rendered biocompatible.

In this paper, we attempt to coat chitosan, a naturally-occurring polymer which is biocompatible, biodegradable and nontoxic, onto the surfaces of nanoparticles. 5 nm gold ( Au ) nanoparticles were chosen for our study as they are commercially available. The presence of a chitosan shell not only renders these nanoparticles biocompatible, the amino and hydroxyl groups of chitosan also allow the immobilization of many biotherapeutic agents. The relationship between the concentration of the chitosan used in the coating process and the thickness of the chitosan shell formed is investigated. It is hoped that the results of this study can also be applied to other nanoparticles, in addition to Au , that are intended to be used in bioapplications.

Biocompatibility and bioactivity of plasma-treated biodegradable poly(butylene succinate)

Poly(butylene succinate) (PBSu), a novel biodegradable aliphatic polyester with excellent processability and mechanical properties, is a promising substance for bone and cartilage repair. However, it typically suffers from insufficient biocompatibility and bioactivity after implantation into the human body. In this work, H(2)O or NH(3) plasma immersion ion implantation (PIII) is conducted for the first time to modify the PBSu surface. Both the treated and control specimens are characterized by X-ray photoelectron spectroscopy, contact angle measurements and atomic force microscopy. The plasma treatments improve the hydrophilicity and roughness of PBSu significantly and the different PIII processes result in similar hydrophilicity and topography. C-OH and C-NH(2) functional groups emerge on the PBSu surface after H(2)O and NH(3) PIII, respectively. The biological results demonstrate that both osteoblast compatibility and apatite formability are enhanced after H(2)O and NH(3) PIII. Furthermore, our results suggest that H(2)O PIII is more effective in rendering PBSu suitable for bone-replacement implants compared to NH(3) PIII.