Graphene oxide as a nanocarrier for gramicidin (GOGD) for high antibacterial performance Hani Nasser Abdelhamid,ab M. Shahnawaz Khaneb and Hui-Fen Wub aDepartment of Chemistry, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan. b Department of Chemistry, Assuit University, Assuit, 71515, Egypt E-mail: hany.abdelhameed@science.au.edu.eg Abstract As a powerful and novel nanocarrier, graphene oxide (GO) is employed to load a water insoluble antibacterial drug, gramicidin (GD), for effective antibacterial treatments. The loaded amount of GD on the surface of GO was calculated and was found to be 14% (wt%). The antibacterial activity of GO modified GD (GOGD) was measured against Pseudomonas aeruginosa and Staphylococcus aureus using plate counting, optical density (OD600), transmission electron microscopy (TEM), fluorescence (2D, 3D) and matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS). The use of multiple analytical approaches adds certainty to the cytotoxicity assessments of GOGD, which shows better efficiency than GO and GD. GOGD has potential wide-ranging effects against different bacterial strains. Nano-cytotoxicity mechanism was discussed in detail, and controversies in earlier results were refuted.
Fig. 1 Characterization of GO and its derivative (GOGD) using TEM for (A) GO, (B) GOGD, (C) UV, (D) FTIR, and (E) calibration curve using MALDI-MS.
Fig. 4 3D-Fluorescence emission of tryptophan for (A) P. aeruginosa and (B) S. aureus after incubation with (a) control, (b) GD, (c) GO and (d) GOGD.
Fig. 2 (A) SEM and (B) EDX analysis of GOGD and biological activity of GD, GO, and GOGD using optical density (OD600) and plate counting. Optical density (OD600) for P. eruginosa (C) and S. aureus (D), and plate counting for P. aeruginosa (E) and S. aureus (F).
Fig. 5 MALDI-MS spectra of (A) P. aeruginosa and (B) S. aureus after incubation with (a) control, (b) GD, (c) GO and (d) GOGD.
Fig. 3 Fluorescence emission of tryptophan for (A) P. aeruginosa and (B) S. aureus after incubation with (a) GD, (b) GO and (c) GOGD.
Fig. 6 TEM images of (A) P. aeruginosa and (B) S. aureus after incubation with (a) control, (b) GD, (c) GO and (d) GOGD. References Hani Nasser Abdelhamid, M. Shahnawaz Khane, HuiFen Wu, Graphene oxide as a nanocarrier for gramicidin (GOGD) for high antibacterial performance. RSC Advances, 2014, 4, 50035-50046