Graphene@Curcumin-Copper Paintable Coatings for the Prevention of Nosocomial Microbial Infection

Abstract

The rise of antimicrobial resistance has brought into focus the urgent need for the next generation of antimicrobial coating. Specifically, the coating of suitable antimicrobial nanomaterials on contact surfaces seems to be an effective method for the disinfection/contact killing of microorganisms. In this study, the antimicrobial coatings of graphene@curcumin-copper (GN@CR-Cu) were prepared using a chemical synthesis methodology. Thus, the prepared GN@CR-Cu slurry was successfully coated on different contact surfaces, and subsequently, the GO in the composite was reduced to graphene (GN) by low-temperature heating/sunlight exposure. Scanning electron microscopy was used to characterize the coated GN@CR-Cu for the coating properties, X-ray photon scattering were used for structural characterization and material confirmation. From the morphological analysis, it was seen that CR and Cu were uniformly distributed throughout the GN network. The nanocomposite coating showed antimicrobial properties by contact-killing mechanisms, which was confirmed by zone inhibition and scanning electron microscopy. The materials showed maximum antibacterial activity against E. coli (24 ± 0.50 mm) followed by P. aeruginosa (18 ± 0.25 mm) at 25 µg/mL spot inoculation on the solid media plate, and a similar trend was observed in the minimum inhibition concentration (80 µg/mL) and bactericidal concentration (160 µg/mL) in liquid media. The synthesized materials showed excellent activity against E. coli and P. aeruginosa. These materials, when coated on different contact surfaces such medical devices, might significantly reduce the risk of nosocomial infection.

Keywords: E. coli; Pseudomonas aeruginosa; antimicrobial; coating; copper; curcumin; graphene.

Figure 1

Schematic representation of the synthesis and antibacterial application of GN@CR-Cu.

Figure 2

Low and high magnification (insets) FESEM images of (a) GN; (b) GN@Cu; (c) GN@CR; and (d) GN@CR-Cu.

Figure 3

Elemental mapping images of (a) GN@CR-Cu; (b) C; (c) O; (d) Cu; and (e) EDS spectrum of GN@CR-Cu.

Figure 4

(a) Low magnification; (b) High magnification HRTEM images of GN@CR-Cu.

Figure 5

XPS spectra of GN@CR-Cu composite: (a) survey scan, (b) C1s, and (c) Cu2p3.

Figure 6

Test bacteria E. coli (a–d), P. aeruginosa (e–h): The zone inhibition by the nanocomposite material on the bacteria cultivated on nutrient agar media plates.

Figure 7

Test bacteria E. coli (a–d), P. aeruginosa (e–h): The minimum inhibition by the nanocomposite material on the bacteria cultivated Petri plates.

Figure 8

The survivability of E. coli (a) and P. aeruginosa (b) in the presence of nanocomposite material. Image showing excellent dose-response, increasing concentration significantly retards bacterial growth.

Figure 9

Scanning electron microscopy image of E. coli without any treatment as a control without an effect on cell morphology (a), and E. coli culture treated with GN (b), GN@CR (c), partial cell damage by the treatment of GN@Cu (d), and complete bacterial cell damage by the treatment of GN@CR-Cu (e).