Plasma Surface Treatment and Grafting of Nano-Gold Surface for Immobilization of Chitosan

Combination of biomaterials with nanotechnology has been applied to the immobilization of chitosan on nano-gold particles by plasma and grafting treatments. In this study, gold (Au) nanoparticles were first synthesized by chemical reduction method using mix- ing solution of HAuCl4 4H2O and sodium citrate or NaBH4. The synthesized gold nanoparticles were then reacted with 11- mercaptoundecanoic acid (MUA) containing thiol group to modify the surface of gold nanoparticle. The MUA-modified Au nanoparti- cles were subjected to O2 plasma pretreatment before the UV light grafting polymerization with N-Isopropylacrylamide (NIPAAm) on the plasma-treated Au nanoparticles to form a thermosensitive polymer on the surface. The functional groups on the grafted Au nanopar- ticles surface were combined with glutaraldehyde to immobilize biological molecules of chitosan. The results show that preparation of nano-Au particles using NaBH4 solution as reductant is better than using the sodium citrate solution. The preferable reaction temperature for the preparation using NaBH4 solution to produce nano-Au particles is 100°C. From the TEM observation the prepared Au nanoparti- cle was spherical-like and about 10~20 nm in size. The zeta potential measurement on the immobilized Au nanoparticles proves that chi- tosan was indeed immobilized on the Au nanoparticles surface.