Surface engineering of poly(lactic acid) by entrapment of modifying species
Surface engineering of poly(lactic acid) by entrapment of modifying species
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DOI：
10.1021/ma9916133
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发表时间：
2000-01
期刊：
影响因子：
5.5
通讯作者：
R. Quirk;M. Davies;S. Tendler;K. Shakesheff
中科院分区：
文献类型：
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作者：
R. Quirk;M. Davies;S. Tendler;K. Shakesheff
在这里，我们描述了一种基于聚合物表面区可逆溶胀过程中分子的捕获来设计聚乳酸表面的新方法。这一策略也可应用于其他聚合物材料的表面工程。由于生物可降解聚合物表面的化学性质决定了生物环境中发生的许多相互作用的性质，因此可能需要进行这样的修饰。1，2聚乳酸及其相关的聚R-羟基酸S在生物材料领域被广泛应用于可吸收缝合线、支架和药物输送装置。近年来，在组织工程、生物相容性和药物释放等领域的相关发展要求将生物活性分子固定在聚乳酸基器件的表面。3对于聚乳酸来说，实现这种固定化的策略是有限的，因为这种聚合物的化学结构缺乏任何用于表面修饰物种的共价接枝的官能团。开发新的表面工程策略的动机是现有策略在聚乳酸(和相关聚合物)上所固有的局限性。随着这种聚合物在新的组织工程和药物输送应用中的开发，对聚乳酸表面工程的需求已经提高。这些应用要求聚合物的表面要么呈现积极促进受体介导的与细胞4、5相互作用的生物分子，要么呈现改变体内蛋白质吸附分布的分子。固定所需的表面修饰物种的一个一般策略是将分子吸附到聚合物表面。然而，这种方法要求表面修饰物种具有合适的表面活性剂性质，并且吸附不会限制活性。另一种策略是在可生物降解聚合物的表面化学结构中引入能够支持共价接枝的官能团。这可以通过将聚合物暴露在改变表面化学结构而不影响主体化学结构的环境中来实现，例如通过聚合物表面的部分水解以产生更高密度的羟基端基。另一种方法，以合成聚(乳酸-共赖氨酸)(PLAL)为例，是重新设计聚合物主链，使其包含带有反应性侧链的单体单元。这种引入官能团的方法可能会有问题，因为它们改变了聚合物在表面的分子量，引入了有限密度的基团，或者需要形成新的聚合物类型。
Here, we describe a new method of engineering PLA surfaces based on the entrapment of molecules during the reversible swelling of the polymer surface region. This strategy may also have applications in the surface engineering of other polymeric materials. Such modifications may be required as the chemical properties of biodegradable polymer surfaces determine the nature of many interactions that occur within biological environments. 1, 2 Poly (lactic acid)(PLA) and related poly (R-hydroxyacid) s are widely employed in biomaterial applications as resorbable sutures, scaffolds, and drug delivery devices. Recently, related developments in the fields of tissue engineering, biocompatibility, and drug delivery have required the immobilization of biologically active molecules on the surfaces of PLA-based devices. 3 Strategies for achieving this immobilization are limited for PLA because the chemical structure of this polymer lacks any functional groups for the covalent grafting of surface-modifying species.The motivation for developing a new surface engineering strategy was the limitations inherent in existing strategies employed on PLA (and related polymers). The need to engineer PLA surfaces has been heightened by the exploitation of this polymer in new tissue engineering and drug delivery applications. These applications require the surfaces of the polymer either to present biological molecules that actively promote receptormediated interactions with cells4, 5 or to present molecules that change the distribution of protein adsorption in vivo. 6 One general strategy to immobilize the required surface-modifying species is to adsorb the molecule to the polymer surface. However, this approach requires that the surface-modifying species possess suitable surfactant properties and that adsorption does not restrict activity. An alternative strategy is to introduce functional groups, capable of supporting covalent grafting, into the surface chemical structure of the biodegradable polymer. This may be achieved by exposing the polymer to environments that alter the chemical structure of the surface without affecting bulk chemical structure, for example by the partial hydrolysis of the polymer surface to yield higher densities of hydroxyl end groups. 7 Another approach, exemplified by the synthesis of poly (lactic acid-co-lysine)(PLAL), is to redesign the polymer backbone so it contains monomer units with reactive side chains. 8, 9 Such methods of introducing functional groups can be problematic because they alter the molecular weight of the polymer at the surface, introduce limited densities of the groups, or require the formation of a new polymer type.