School of Materials Science and Engineering, Nanyang Technological University, Block N4.1-02-06, Nanyang Avenue, Singapore 639798.
Mol Pharm. 2011 Dec 5;8(6):2173-82. doi: 10.1021/mp200513b. Epub 2011 Nov 11.
Quantification of protein-polymer colocalization in a phase-separated polymer blend gives important insights into the protein release mechanism. Here, we report on the first visualization of protein-poly(ethylene glycol) (protein-PEG) colocalization in poly(ε-caprolactone)/poly(ethylene glycol) (PCL/PEG) blend films using a combined application of confocal Raman mapping and confocal laser scanning microscopy (CLSM) imaging. The degree of protein-PEG colocalization was further quantified via a novel image processing technique. This technique also allowed us to characterize the 3-D protein distribution within the films. Our results showed that the proteins were homogeneously distributed within the film matrix, independent of PEG content. However, the degree of protein-PEG colocalization was inversely proportional to PEG content, ranging from 65 to 94%. This quantitative data on protein-PEG colocalization was used along with in vitro PEG leaching profile to construct a predictive model for overall protein release. Our prediction matched well with the experimental protein release profile, which is characterized by an initial burst release and a subsequent slower diffusional release. More importantly, the success of this predictive model has highlighted the influence of protein-PEG colocalization on the protein release mechanism.
在相分离聚合物共混物中定量蛋白质-聚合物共定位，可深入了解蛋白质释放机制。在这里，我们报告了使用共焦拉曼映射和共焦激光扫描显微镜（CLSM）成像的组合首次可视化聚（ε-己内酯）/聚（乙二醇）（PCL/PEG）共混膜中蛋白质-聚乙二醇（protein-PEG）共定位的情况。通过一种新的图像处理技术进一步量化了蛋白质-PEG 共定位的程度。该技术还使我们能够表征薄膜内的三维蛋白质分布。我们的结果表明，蛋白质在薄膜基质中均匀分布，与 PEG 含量无关。然而，蛋白质-PEG 共定位的程度与 PEG 含量成反比，范围为 65%至 94%。该蛋白质-PEG 共定位的定量数据与体外 PEG 浸出曲线一起用于构建整体蛋白质释放的预测模型。我们的预测与实验蛋白质释放曲线吻合良好，其特征是初始突释和随后较慢的扩散释放。更重要的是，该预测模型的成功突出了蛋白质-PEG 共定位对蛋白质释放机制的影响。
