Free-radical-mediated protein inactivation and recovery during protein photoencapsulation
Free-radical-mediated protein inactivation and recovery during protein photoencapsulation
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DOI：
10.1021/bm700782c
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发表时间：
2008-01-01
影响因子：
6.2
通讯作者：
Metters, Andrew T.
中科院分区：
文献类型：
--
作者：
Lin, Chien-Chi;Sawicki, Suzanne M.;Metters, Andrew T.
蛋白质治疗药物的光胶囊化对于制备生物分子负载水凝胶具有很大的吸引力，可用于各种生物医学应用。然而，必须仔细评估在光封装过程中产生的高活性自由基的有害影响，以保持有效的水凝胶交联，同时保留被封装生物分子的结构和生物活性。在这里，我们研究了自由基介导的失活和光固化水凝胶中蛋白质的不完全释放，利用溶菌酶作为一个保守的模型系统。研究了影响溶菌酶结构完整性和生物活性的因素。研究发现，在较高的光引发剂浓度和较长的聚合时间下，溶菌酶的一部分与聚合物链共轭。我们还发现，亲水性更强的光引发剂irgacu -2959 （i - 2959,2 -羟基-1-[4-（羟基乙氧基）苯基]-2-甲基-1-丙烷）比疏水性光引发剂irgacu -651 （i - 651,2,2 -二甲氧基-2-苯基苯乙酮）对溶菌酶的损伤更大，尽管I-2959先前已被证明具有更强的细胞相容性。此外，虽然非丙烯酸PEG在水凝胶固化过程中只能提供有限的保护，但在任何光引发剂的存在下，丙烯酸PEG大分子都能有效地保持溶菌酶的结构完整性和生物活性。总的来说，这些发现表明必须如何优化光聚合条件（例如，光引发剂的类型和浓度，紫外线照射时间等）才能获得能够保持蛋白质生物活性并提供最大蛋白质释放的功能性水凝胶装置。
Photoencapsulation of protein therapeutics is very attractive for preparing biomolecule-loaded hydrogels for a variety of biomedical applications. However, detrimental effects of highly active radical species generated during photoencapsulation must be carefully evaluated to maintain efficient hydrogel cross-linking while preserving the structure and bioactivity of encapsulated biomolecules. Here, we examine the free-radical-mediated inactivation and incomplete release of proteins from photocurable hydrogels utilizing lysozyme as a conservative model system. Various protein photoencapsulation conditions were tested to determine the factors affecting lysozyme structural integrity and bioactivity. It was found that a portion of the lysozyme becomes conjugated to polymer chains at high photoinitiator concentrations and long polymerization times. We also found that the more hydrophilic photoinitiator Irgacure-2959 (I-2959, 2-hydroxy-1-[4-(hydroxyethoxy)phenyl]-2-methyl-1-propanone) causes more damage to lysozyme compared to the hydrophobic photoinitiator Irgacure-651 (I-651, 2,2-dimethoxy-2-phenylacetophenone), even though I-2959 has been previously shown to be more cytocompatible. Furthermore, while nonacrylated PEG provides only limited protection from the denaturing free radicals that are present during hydrogel curing, acrylated PEG macromers effectively preserve lysozyme structural integrity and bioactivity in the presence of either photoinitiator. Overall, these findings indicate how photopolymerization conditions (e.g., photoinitiator type and concentration, UV exposure time, etc.) must be optimized to obtain a functional hydrogel device that can preserve protein bioactivity and provide maximal protein release.