†Residues and Resource Reclamation Centre (R3C), Nanyang Environment and Water Research Institute (NEWRI), Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore.
⊥Graphene Research Center, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore.
ACS Appl Mater Interfaces. 2015 Apr 22;7(15):8275-83. doi: 10.1021/acsami.5b01440. Epub 2015 Apr 8.
Graphene foams (GFs) are versatile nanoplatforms for biomedical applications because of their excellent physical, chemical, and mechanical properties. However, the brittleness and inflexibility of pristine GF (pGF) are some of the important factors restricting their widespread application. Here, a chemical-vapor-deposition-assisted method was used to synthesize 3D GFs, which were subsequently spin-coated with polymer to produce polymer-enriched 3D GFs with high conductivity and flexibility. Compared to pGF, both poly(vinylidene fluoride)-enriched GF (PVDF/GF) and polycaprolactone-enriched GF (PCL/GF) scaffolds showed improved flexibility and handleability. Despite the presence of the polymers, the polymer-enriched 3D GF scaffolds retained high levels of electrical conductivity because of the presence of microcracks that allowed for the flow of electrons through the material. In addition, polymer enrichment of GF led to an enhancement in the formation of calcium phosphate (Ca-P) compounds when the scaffolds were exposed to simulated body fluid. Between the two polymers tested, PCL enrichment of GF resulted in a higher in vitro mineralization nucleation rate because the oxygen-containing functional group of PCL had a higher affinity for Ca-P deposition and formation compared to the polar carbon-fluorine (C-F) bond in PVDF. Taken together, our current findings are a stepping stone toward future applications of polymer-enriched 3D GFs in the treatment of bone defects as well as other biomedical applications.
石墨烯泡沫（GFs）由于其优异的物理、化学和机械性能，是用于生物医学应用的多功能纳米平台。然而，原始 GF（pGF）的脆性和不灵活性是限制其广泛应用的一些重要因素。在这里，使用化学气相沉积辅助的方法合成了 3D GFs，然后用聚合物旋涂在其表面，生产出具有高导电性和柔韧性的聚合物富集 3D GFs。与 pGF 相比，聚偏二氟乙烯（PVDF）富集 GF（PVDF/GF）和聚己内酯（PCL）富集 GF（PCL/GF）支架都表现出更好的柔韧性和可操作性。尽管存在聚合物，但由于微裂纹的存在允许电子在材料中流动，聚合物富集的 3D GF 支架仍然保持着高电导率。此外，当支架暴露于模拟体液中时，GF 的聚合物富集导致磷酸钙（Ca-P）化合物的形成得到增强。在测试的两种聚合物中，由于聚己内酯（PCL）中的含氧官能团与 Ca-P 的沉积和形成具有更高的亲和力，与聚偏二氟乙烯（PVDF）中的极性碳-氟（C-F）键相比，PCL 富集 GF 导致体外矿化成核速率更高。总之，我们目前的研究结果为未来聚合物富集 3D GFs 在治疗骨缺损以及其他生物医学应用中的应用铺平了道路。
