Ameringer Thomas, Ercole Francesca, Tsang Kelly M, Coad Bryan R, Hou Xueliang, Rodda Andrew, Nisbet David R, Thissen Helmut, Evans Richard A, Meagher Laurence, Forsythe John S
ANU College of Engineering and Computer Science, Australian National University, Canberra ACT, 0200, Australia,
Biointerphases. 2013 Dec;8(1):16. doi: 10.1186/1559-4106-8-16. Epub 2013 Jul 5.
The ability to present signalling molecules within a low fouling 3D environment that mimics the extracellular matrix is an important goal for a range of biomedical applications, both in vitro and in vivo. Cell responses can be triggered by non-specific protein interactions occurring on the surface of a biomaterial, which is an undesirable process when studying specific receptor-ligand interactions. It is therefore useful to present specific ligands of interest to cell surface receptors in a 3D environment that minimizes non-specific interactions with biomolecules, such as proteins.
In this study, surface-initiated atom transfer radical polymerization (SI-ATRP) of poly(ethylene glycol)-based monomers was carried out from the surface of electrospun fibers composed of a styrene/vinylbenzyl chloride copolymer. Surface initiated radical addition-fragmentation chain transfer (SI-RAFT) polymerisation was also carried out to generate bottle brush copolymer coatings consisting of poly(acrylic acid) and poly(acrylamide). These were grown from surface trithiocarbonate groups generated from the chloromethyl styrene moieties existing in the original synthesised polymer. XPS was used to characterise the surface composition of the fibers after grafting and after coupling with fluorine functional XPS labels.
Bottle brush type coatings were able to be produced by ATRP which consisted of poly(ethylene glycol) methacrylate and a terminal alkyne-functionalised monomer. The ATRP coatings showed reduced non-specific protein adsorption, as a result of effective PEG incorporation and pendant alkynes groups existing as part of the brushes allowed for further conjugation of via azide-alkyne Huisgen 1,3-dipolar cycloaddition. In the case of RAFT, carboxylic acid moieties were effectively coupled to an amine label via amide bond formation. In each case XPS analysis demonstrated that covalent immobilisation had effectively taken place.
Overall, the studies presented an effective platform for the preparation of 3D scaffolds which contain effective conjugation sites for attachment of specific bioactive signals of interest, as well as actively reducing non-specific protein interactions.
在模拟细胞外基质的低污染三维环境中呈现信号分子的能力，是一系列体外和体内生物医学应用的重要目标。生物材料表面发生的非特异性蛋白质相互作用可触发细胞反应，而在研究特异性受体-配体相互作用时，这是一个不良过程。因此，在三维环境中向细胞表面受体呈现感兴趣的特异性配体很有用，这种环境可最大限度减少与蛋白质等生物分子的非特异性相互作用。
在本研究中，基于聚乙二醇的单体的表面引发原子转移自由基聚合（SI-ATRP）是从由苯乙烯/乙烯基苄基氯共聚物组成的电纺纤维表面进行的。还进行了表面引发自由基加成-断裂链转移（SI-RAFT）聚合，以生成由聚丙烯酸和聚丙烯酰胺组成的瓶刷状共聚物涂层。这些涂层是从原始合成聚合物中存在的氯甲基苯乙烯部分产生的表面三硫代碳酸酯基团生长而来的。X射线光电子能谱（XPS）用于表征接枝后以及与氟功能XPS标记偶联后的纤维表面组成。
通过ATRP能够制备由聚甲基丙烯酸乙二醇酯和末端炔烃功能化单体组成的瓶刷型涂层。由于有效的聚乙二醇掺入以及作为刷的一部分存在的侧链炔烃基团允许通过叠氮化物-炔烃惠斯根1,3-偶极环加成进一步共轭，ATRP涂层显示出减少的非特异性蛋白质吸附。在RAFT的情况下，羧酸部分通过酰胺键形成有效地与胺标记偶联。在每种情况下，XPS分析表明已经有效地发生了共价固定。
总体而言，这些研究提出了一个有效的平台，用于制备三维支架，该支架包含用于连接感兴趣特定生物活性信号的有效共轭位点，并能有效减少非特异性蛋白质相互作用。
