Tam Susan K, Dusseault Julie, Polizu Stefania, Ménard Martin, Hallé Jean-Pierre, Yahia L'Hocine
Laboratoire d'Innovation et d'Analyse de Bioperformance, Ecole Polytechnique de Montréal, C.P. 6079, succ. Centre-ville, Montréal, Qué., Canada H3C 3A7.
Biomaterials. 2006 Mar;27(8):1296-305. doi: 10.1016/j.biomaterials.2005.08.027. Epub 2005 Sep 9.
Alginate is frequently used for cell encapsulation, but its biocompatibility is neither optimal nor reproducible. Purifying the alginate is critical for achieving a suitable biocompatibility. However, published purification methods vary in efficiency and may induce changes in polymer biofunctionality. Applying X-ray photoelectron spectroscopy, we showed that commercial alginates, purified by in-house and industrial methods, contained elemental impurities that contributed 0.41-1.73% of their atomic composition. Residual contaminants were identified to be proteins (nitrogen/COOH), endotoxins (phosphorus), and fucoidans (sulphur). Studies using attenuated total reflectance Fourier transform infrared spectroscopy suggested that trace contamination did not alter the alginate molecular structure. Alginate hydrophilicity increased by 19-40% after purification, in correlation with a reduction in protein and polyphenol content. Solution viscosity of the alginate increased by 28-108% after purification, in correlation with a reduction in protein content. These results demonstrate that commercial alginates contain potentially immunogenic contaminants that are not completely eliminated by current purification methods. Moreover, these contaminants alter the functional properties of the alginate in a manner that may compromise biocompatibility: Hydrophilicity may affect protein adsorption and solution viscosity influences the morphology of alginate-based microcapsules. These findings highlight the need to improve and better control alginate purity to ensure a reproducible biofunctionality and optimal biocompatibility of alginate and microcapsules.
藻酸盐常用于细胞封装，但其生物相容性既不理想也不可重复。纯化藻酸盐对于实现合适的生物相容性至关重要。然而，已发表的纯化方法在效率上存在差异，并且可能会引起聚合物生物功能的变化。通过应用X射线光电子能谱，我们发现，采用内部和工业方法纯化的市售藻酸盐含有元素杂质，这些杂质占其原子组成的0.41 - 1.73%。已鉴定出残留污染物为蛋白质（氮/羧基）、内毒素（磷）和岩藻依聚糖（硫）。使用衰减全反射傅里叶变换红外光谱进行的研究表明，微量污染并未改变藻酸盐的分子结构。纯化后，藻酸盐的亲水性提高了19 - 40%，这与蛋白质和多酚含量的降低相关。纯化后，藻酸盐的溶液粘度提高了28 - 108%，这与蛋白质含量的降低相关。这些结果表明，市售藻酸盐含有潜在的免疫原性污染物，目前的纯化方法无法将其完全去除。此外，这些污染物以可能损害生物相容性的方式改变了藻酸盐的功能特性：亲水性可能影响蛋白质吸附，溶液粘度影响藻酸盐基微胶囊的形态。这些发现凸显了改善和更好地控制藻酸盐纯度的必要性，以确保藻酸盐和微胶囊具有可重复的生物功能和最佳的生物相容性。
