可缓释富血小板血浆生长因子的新型自组装多肽水凝胶制备及性能表征

Preparation and characterization of a novel self-assembled polypeptide hydrogel sustainably releasing platelet-rich plasma growth factors

背景:富血小板血浆水凝胶由于生长因子的突发释放与伤口部位蛋白酶的快速清除,导致生长因子在伤口部位的停留时间较短,近年来研究者关注利用水凝胶材料包封富血小板血浆,以改善富血小板血浆水凝胶的不足。目的:制备自组装多肽-富血小板血浆水凝胶,探究其对富血小板血浆生物活性因子释放的影响。方法:采用固相合成法合成自组装多肽,以D-PBS配制成溶液。将不同体积的多肽溶液分别与富血小板血浆、氯化钙/凝血酶溶液混合制备水凝胶,使体系中多肽的最终质量分数分别为0.1%,0.3%,0.5%,观察成水凝胶状态,并体外检测富血小板血浆中生长因子释放情况。将质量分数1%多肽溶液与质量分数1%人血清白蛋白溶液混合激发多肽自组装,使多肽的最终质量分数分别为0.1%,0.3%,0.5%,观察液体流动状态,并检测自组装多肽的流变力学性能。通过扫描电镜与透射电镜观察多肽(质量分数分别为0.1%,0.001%)-人血清白蛋白溶液的微观结构。结果与结论:①不同体积多肽溶液与富血小板血浆均可形成水凝胶,与富血小板血浆水凝胶相比,0.1%,0.3%多肽-富血小板血浆凝胶可缓解表皮生长因子、血管内皮生长因子的突发释放,延长释放时间至48 h。②添加人血清白蛋白后,0.1%多肽组仍呈流动液体,0.3%多肽组呈半液体状态,0.5%多肽组激发自组装形成水凝胶,确定富血小板血浆中人血清白蛋白可激发多肽自组装;随着多肽质量分数的提高,自组装多肽的存储模量越高,越容易成胶。③透射电镜下可见,添加人血清白蛋白前,多肽纳米纤维较短且无序堆积;添加人血清白蛋白后,多肽纳米纤维明显变长,并且相互交联成束,形成致密的纤维网络结构。扫描电镜下可见,添加人血清白蛋白前,多肽呈无序堆积的片状结构;添加人血清白蛋白后,多肽自组装成相互交联且有序密集排列的多孔状结构。④结果显示,新型自组装多肽可由富血小板血浆激发自组装,根据人血清白蛋白与多肽的比例可精准调节自组装效果,且多肽对富血小板血浆生长因子有缓释作用,可作为一种新型的生物材料应用于组织修复。

BACKGROUND:Due to the sudden release and the rapid removal by proteases,platelet-rich plasma hydrogel leads to shorter residence times of growth factors at the wound site.In recent years,researchers have focused on the use of hydrogels to encapsulate platelet-rich plasma in order to improve the deficiency of platelet-rich plasma hydrogels.OBJECTIVE:To prepare self-assembled polypeptide-platelet-rich plasma hydrogel and to explore its effects on the release of bioactive factors of platelet-rich plasma.METHODS:The self-assembled polypeptide was synthesized by the solid-phase synthesis method,and the solution was prepared by D-PBS.Hydrogels were prepared by mixing different volumes of polypeptide solutions with platelet-rich plasma and calcium chloride/thrombin solutions,so that the final mass fraction of polypeptides in the system was 0.1%,0.3%,and 0.5%,respectively.The hydrogel state was observed,and the release of growth factors in platelet-rich plasma was detected in vitro.The polypeptide self-assembly was stimulated by mixing 1%polypeptide solution with 1%human serum albumin solution,so that the final mass fraction of the polypeptide was 0.1%,0.3%,and 0.5%,respectively.The flow state of the liquid was observed,and the rheological mechanical properties of the self-assembled polypeptide were tested.The microstructure of polypeptide(mass fraction of 0.1%and 0.001%)-human serum albumin solution was observed by scanning electron microscope and transmission electron microscope.RESULTS AND CONCLUSION:(1)Hydrogels could be formed between different volumes of polypeptide solution and platelet-rich plasma.Compared with platelet-rich plasma hydrogels,0.1%and 0.3%polypeptide-platelet-rich plasma hydrogels could alleviate the sudden release of epidermal growth factor and vascular endothelial growth factor,and extend the release time to 48 hours.(2)After the addition of human serum albumin,the 0.1%polypeptide group still exhibited a flowing liquid,the 0.3%polypeptide group was semi-liquid,and the 0.5%polypeptide group stimulated self-assembly to form hydrogel.It was determined that human serum albumin in platelet-rich plasma could stimulate the self-assembly of polypeptides.With the increase of the mass fraction of the polypeptide,the higher the storage modulus of the self-assembled polypeptide,the easier it was to form glue.(3)Transmission electron microscopy exhibited that the polypeptide nanofibers were short and disordered before the addition of human serum albumin.After the addition of human serum albumin,the polypeptide nanofibers became significantly longer and cross-linked into bundles,forming a dense fiber network structure.Under a scanning electron microscope,the polypeptides displayed a disordered lamellar structure before adding human serum albumin.After the addition of human serum albumin,the polypeptides self-assembled into cross-linked and densely arranged porous structures.(4)In conclusion,the novel polypeptide can self-assemble triggered by platelet-rich plasma and the self-assembly effect can be accurately adjusted according to the ratio of human serum albumin to polypeptide.This polypeptide has a sustained release effect on the growth factors of platelet-rich plasma,which can be used as a new biomaterial for tissue repair.