The Amino Group Effect of Plasma Irradiation for Surface Treatment on Hydroxyapatite (HA) Artificial Bone

摘要

Recently, plasma biomedical application has been developed and used to enhance the surface of scaffold such as polymer structure; this development leads to the possibility of applying plasma irradiation for bone transplantation such as Hydroxyapatite (HA) artificial bone that holds cells or tissues together. Plasma irradiation is expected to modify surface/functional group and to improve the ability of healing process. In the previous research, hydrophilicity on HA has been improved by plasma treatment with mixture of O_2 and He gases. From that study, we explore it further by investigating the amino group effect on HA artificial bone surface using plasma treatment. Plasma system for HA treatments are Inverter Plasma and Capacitively Coupled Plasma (CCP). The pulse plasma is generated by inverter power supply and mixedgases of He, N_2, CH_4, at a pressure of 100 Pa, voltage (Vpp) of 2.4 kV and frequency of 5 kHz. We also prepared pulsed plasma polymerization of cyclopropylamine (CPA) using CCP and mixed with Ar at a pressure of 50 Pa, voltage of 66.5 V, power of 40 W, the repetition frequency of 500 Hz and duty cycle 33,3%. The spectra inside the inverter plasma chamber have been identified by Optical Emission Spectroscopy (EOS). Because the sterilization prior to the animal experiment is needed, it is necessary to confirm the amino (–NH_2) group intensity. We use sterilization for animal experiment, i.e Ethylene Oxide Gas (EOG), autoclave, and γ-ray sterilization. The amino group after irradiation and sterilization is investigated by derivatization of 4-trifluoromethyl-benzaldehyde (TFBA) vapours . To identify chemical bonding state after irradiation and sterilization, we analyze it using X-ray photoelectron spectroscopy (XPS). We calculate the atomic concentration of C, N and another element that deposit on HA surface using Shirley background type. The result shows that the C and N have increased using plasma treatment. It indicates that plasma treatments give rise to N-containing functionalities or amino group (–NH_2) on the artificial bone surface. Furthermore, after EOG sterilization, prime amine still appears on HA artificial bone yet the concentration is higher than other sterilization as shown in Figure 1. Regarding CPA deposition usingCCP, we will show the result in the symposium.