Resumen:
The coupling reactions of polyethylene glycol (PEG) with two different nano-carbonaceous
materials, graphene oxide (GO) and expanded graphene oxide (EGO), were achieved by amide bond
formations. These reactions yielded PEGylated graphene oxides, GO-PEG and EGO-PEG. Whilst
presence of the newly formed amide links (NH-CO) were confirmed by FTIR stretches observed
at 1732 cm−1 and 1712 cm−1
, the associated Raman D- and G-bands resonated at 1311/1318 cm−1
and 1584/1595 cm−1 had shown the carbonaceous structures in both PEGylated products remain
unchanged. Whilst SEM images revealed the nano-sheet structures in all the GO derivatives (GO/EGO
and GO-PEG/EGO-PEG), TEM images clearly showed the nano-structures of both GO-PEG and
EGO-PEG had undergone significant morphological changes from their starting materials after the
PEGylated processes. The successful PEGylations were also indicated by the change of pH values
measured in the starting GO/EGO (pH 2.6–3.3) and the PEGylated GO-PEG/EGO-PEG (pH 6.6–6.9)
products. Initial antifungal activities of selective metallic nanomaterials (ZnO and Cu) and the four
GO derivatives were screened against Candida albicans using the in vitro cut-well meth...