Characterisation of a phenol-derived polymeric bone glue

背景：有几种不同的骨折固定技术，并不断完善。在骨折愈合和软组织损伤方面，生物相容性变得越来越重要。特别是复杂的多骨折块骨折和关节内骨折，手术重建和固定仍然是一个挑战。因此，开发体内适用的骨胶将是接骨技术的重大进步。绝大多数报道的生物粘附分子与生物聚合物的缀合反应是通过直接酰胺化反应进行的。在体内开发有效骨胶的主要问题是需要精确的pH控制，添加过量的反应物以移植到生物聚合物上以及副产物的存在。我们的目的是研究一种新的骨粘合剂，使用含有苯酚衍生的生物粘合剂分子的聚合物组合物。有证据表明，这种缀合反应比目前用于将胺连接到生物聚合物的方法更有效，并且在反应期间不需要精确的pH控制或pH变化才有效。材料和方法：首先，必须建立通过稳健的酰胺化技术将生物粘附分子合成到生物聚合物如明胶上。将通过1H NMR、分光光度法、流变学和色谱法对合成的生物缀合物进行表征。通常，将收集接枝效率、产率、生物聚合物分子量的保持、溶液的粘弹性性质的变化。将评价细胞毒性，评估hTERT-BJ 1成纤维细胞在与缀合物和交联缀合物的提取物接触后的活力。在完成第一步之后，将分析制备的制剂的生物粘附性质以及制备的制剂的止血性质。本项目的主要目的是对一种新型生物粘合剂在粘附于潮湿表面、无毒、制备和灭菌可行性方面进行临床前表征，具有足够的强度以在所需时间内稳定骨-骨界面，并且不干扰骨修复。我们假设，已经用作止血剂的明胶，经生物粘附性苯酚衍生官能团改性后，可以在虎红溶液中使用可见光粘合骨片。由于止血效果，该制剂可以在体内固化，同时在可见光激活时粘附到周围组织上。临床意义：有效和生物相容性骨胶的开发将意味着最新骨接合技术的重要进步。有前途的应用领域将是复杂的多碎片骨折以及婴儿骨折的治疗。

Background: There are several different fixation techniques for bone fractures that are continually refined. Bio-compatibility, in terms of fracture healing and soft tissue damage, becomes more and more important. Especially complex multi-fragment fractures and intraarticular fractures remain a challange for surgical reconstruction and fixation. Therefore, the development of an in-vivo applicable bone glue would be a substantial advancement in osteosynthesis techniques. The vast majority of the reported conjugation reactions of bio-adhesive molecules to biopolymers are performed by direct amidation reaction. A major problem in the develoment of an effective bone glue in vivo is the need of accurate pH control, addition of excess of reactant to graft on the biopolymer and the presence of by-products. Our aim is to examine a novel bone adhesive using polymeric composition containing phenol derived bio-adhesive molecules. There is evidence that this conjugation reaction is more efficient than current methods for ligation of amines to biopolymers and does not require accurate pH control or pH shift during the reaction to be effective. Material and Methods: First, synthesis of bio-adhesive molecules onto biopolymes such as gelatin by a robust amidation technique has to be established. The characterisation of the synthesised bioconjugates will be done via 1H NMR, spectrophotometry, rheology and chromatography. Typically, grafting efficiency, yield, conservation of biopolymers molecular weight, changes in viscoelastic properties of the solutions will be collected. Cytotoxicity will be evaluated assessing the viability of hTERT-BJ1 fibroblasts after contact with conjugates and extracts from the crosslinked conjugates. After this first step is done, the bioadhesion property of prepared formulations will be analysed as well as hemostatic property of prepared formulations.Objective: Primary aim of this project is the preclinical characterisation of a novel bio-adhesive in terms of adhesion to moist surfaces, non toxicicty, preparation and sterilisation feasibility, sufficient strength to stabilise the bone-bone interface for the required time and no interference with the bone repair. We hypothesised that gelatin, already used as an hemostatic, modified with bio-adhesive phenol derived functionalities could be applied in solution with Rose Bengal to glue bone pieces using visible light. The formulation could set in vivo due to the hemostatic effect and simultaneously adhere to the surrounding tissue upon visible light activation.Clinical relevance: The development of an effective and bio-compatative bone glue would mean a crucial advancement in up to date osteosynthesis techniques. Promising areas of application would be complex multi-fragment fractures as well as treatment of infantile fractures.