衰减全反射-红外成像研究聚乳酸/生物活性玻璃复合材料的体外矿化过程

Characterization of In vitro Mineralization of Porous Poly( L-Lactic Acid) /Bioactive Glass Composites by Attenuated Total Reflectance-Fourier Transform Infrared Mapping

采用衰减全反射-红外成像技术（ATR-FTIR mapping）对多孔聚乳酸/生物活性玻璃（PLLA/BG）复合材料在PBS缓冲液中的矿化过程进行了研究。光谱分辨率为8 cm!1,累加扫描8次,基于A1044/A1755的吸光度比值生成红外图像。成像结果表明,随着矿化进行,材料表面产生的羟基磷灰石（HA）也逐渐增多,当矿化进行到84 d后,材料表面大部分已被HA覆盖。但随着矿化时间的继续延长,矿化不均匀性也逐渐加剧。矿化曲线显示矿化过程存在4个阶段：矿化初期（前21 d）,产生的HA很少;矿化增长期（21~70 d）,BG逐渐转变为HA;快速增长期（70~91 d）,矿化加速,并在91 d时达到最大;矿化后期（91 d后）,曲线先显示平稳然后又从105 d起出现下降。研究表明,红外成像技术有望成为骨组织工程支架材料的重要研究工具。

Attenuated total reflectance-Fourier transform infrared （ATR-FTIR） mapping was used to characterize the mineralization of porous poly （L-lactic acid）/bioactive glass （PLLA/BG） composite in PBS solution. FTIR images were generated based on the ratio of the absorbanee of the band at 1044 em-t to the one at 1755 cm-l（Al044/A1755） at a resolution of 8 cm-1 with 8-coadded scans. The imaging results show that the amount of hydroxyapatite （HA） on the surface of the composites increases with soaking time and most of the surface area are covered by HA after being mineralized for 84 days. However, the heterogeneous mineralization increases with more time. The mineralization curve from the average spectra further suggests that there are four stages during mineralization. At the initial one （less than 21 days）, the amounts of HA are small; at the growth one （from 21 to 70 days）, BG is gradually converted to HA; at the rapid growth one （from 70 to 91 days）, the mineralization is accelerated and reached up to the maximum at 91 day; and at the late stage （larger than 91 days）, the curve becomes steady at first and then declines from 105 days. Our results suggest that ATR-FTIR mapping is promised to be an important tool for study of the scaffold in bone tissue engineering.