Cellulose-Derived\nNanographene Oxide Reinforced Macroporous\nScaffolds of High Internal Phase Emulsion-Templated Cross-Linked Poly(ε-caprolactone)

Abstract

Cellulose-derived nanographene oxide (nGO)-type carbon\ndot reinforced\nporous scaffolds of poly­(ε-caprolactone) (PCL) were developed\nas templates from high internal phase emulsions (HIPE). The mechanical\nstrength, structural integrity, and reusability of the scaffolds were\nenhanced via in situ cross-linking. An oil-in-oil (o/o) HIPE of ε-caprolactone\nmonomer (CL) was made for this purpose, and the ring-opening polymerization\nof a continuous phase comprised of CL, catalyst (Sn­(Oct)₂), and cross-linker (bis­(caprolactone-4-yl)) (BCY) was carried out.\nThe functionalization of scaffolds with nGO was assessed along with\nits role as an effective Pickering stabilizer of the HIPEs. The pore\nsize and porosity of the scaffolds were governed by HIPE morphology,\nwhich in turn was controlled by the amount of nGO and the volume fraction\nof the dispersed phase. The nGO-functionalized scaffolds of cross-linked\nPCL thus prepared were characterized for their morphological structure,\nmechanical strength, and oil sorption capacity. Enhanced oil adsorption\nof nGO-functionalized scaffolds proved them to be of higher potency\ncompared to those made of neat PCL. Superior compressive strength\nand reusability of scaffolds for oil adsorption up to 40 times while\nmaintaining the structural integrity for ≥25 sorption–desorption\ncycles added extra value to such scaffolds. The scaffolds also had\nexcellent cell viability as evaluated by MG63 osteoblast-like cells\nand some bioactivity in the form of calcium phosphate mineralization\non the surface of the scaffolds.