低温等离子体对医用胶原膜表面改性的研究

STUDY ON THE SURFACE MODIFICATION OF THE COLLAGEN FILM FOR MEDICINE BY LOW TEMPERATURE PLASMA

天然胶原生物材料经辉光放电等离子体改性后，表面化学组分和结构改变．通过测量接触角，光电子谱和红外分析，表明其表面能提高；表面引进了羧基，因而大大提高了表面的极性．这些结果对研制生物医用复合材料具有重要的科学意义和实用价值．

Various polymer materials used in the medical field are required three essential factors: functional characteristic, mechanical property and biological compatibility. It is difficult to make medical products with these three essential factors by using single material. Therefore material surface modification is nec essary. The natural collagen film is an extracted natural biological material refined from muscle of ox and has good biological compatibility. This paper will describe the change of chemical component and structure of collagen film treated by glow discharge plasma. The thickness of film is about 20pm. The device for plasma treament is adopted capacitance coupling rf discharge. Working gases are Ar. O2 and N2, supply power is50 W, treatment time'is 30 s to 15 min.The effects of plasma modification on surface energy of collagen film is that the contact angle of collage surfae is decreased greatly and its surface energy tends to increase after plasma modification. The analysis of polarity and dispersion component rate in total surface energy shows that the Percentage of polarity component energy increased, but the corresponding value of dispersion component is decreased greatly. Therfore the increase of total surface energy is the results of the increase of polarity component. Then polarity groups are introduced into surfaCe of collagen film.IR analysis of the surface of collagen film modified by plasma shows that opposite symmetry absorptive frequency of carboxyl group COO- of ion model appears near 1550 cm-1, but it appears near 1710 cm-1 for carboxyl group of non-ion model, while for amino group of ion model (-NH+3) it is near 1620 cm-1. Through the comparison of three spectrum, we can see the absorption of COOH is increased obviously after oxygen or argon plasma modification.Analysis of ESCA of collagen film modified by plasma shows that C15 spectrum peak of collagen film can by seen as overlap of four spectrum peaks. They are C-H (- 285 eV). C-NH2 and C-OH (- 286.2W. C= O and (￣-88 eV). COOH (289.2 eV). The percentage of different spectrum peak in C1s, is changed obviously, the Percentage of COOH peak in C1s, is increased after plasma modification. It indicates that the increment of carboxyl groups of collagen surface is caused by plasma modification,'which is the same as the results drawn from IR analysis above.