Fabrication and Characterization of an Electrospun PHA/Graphene Silver Nanocomposite Scaffold for Antibacterial Applications

Abstract

Many wounds are unresponsive to currently available treatment techniques and therefore there is an immense need to explore suitable materials, including biomaterials, which could be considered as the crucial factor to accelerate the healing cascade. In this study, we fabricated polyhydroxyalkanoate-based antibacterial mats via an electrospinning technique. One-pot green synthesized graphene-decorated silver nanoparticles (GAg) were incorporated into the fibres of poly-3 hydroxybutarate-co-12 mol.% hydroxyhexanoate (P3HB-co-12 mol.% HHx), a co-polymer of the polyhydroxyalkanoate (PHA) family which is highly biocompatible, biodegradable, and flexible in nature. The synthesized PHA/GAg biomaterial has been characterized by field emission scanning electron microscopy (FESEM), elemental mapping, thermogravimetric analysis (TGA), UV-visible spectroscopy (UV-vis), and Fourier transform infrared spectroscopy (FTIR). An in vitro antibacterial analysis was performed to investigate the efficacy of PHA/GAg against gram-positive Staphylococcus aureus (S. aureus) strain 12,600 ATCC and gram-negative Escherichia coli (E. coli) strain 8739 ATCC. The results indicated that the PHA/GAg demonstrated significant reduction of S. aureus and E. coli as compared to bare PHA or PHA- reduced graphene oxide (rGO) in 2 h of time. The p value (p < 0.05) was obtained by using a two-sample t-test distribution.

Keywords: PHA; antibacterial; electrospun biomaterial; graphene; silver nanoparticles.

Figure 1

General Structure of Polyhydroxyalkanoate.

Figure 2

Schematic illustration of preparing Ganoderma lucidium extract.

Figure 3

Green synthesis of the reduced graphene oxide (rGO) and silver nanoparticles (Ag-NPs) (GAg) nanocomposite.

Figure 4

Schematic diagram of electro spinning PHA/GAg scaffold.

Figure 5

SEM images for the rGO (a), Gag (b), and PHA/GAg electrospun mats (c). Elemental mapping of a sample PHA/GAg scaffold is shown in figure (d–h) respectively.

Figure 6

UV-vis spectra obtained after the green synthesis of Ag-NPs (a), rGO (b), and GAg (c).

Figure 7

Dynamic light scatter of GAg nanocomposite.

Figure 8

FTIR spectra of rGO and GAg (a) and PHA/GAg (b) nanocomposites.

Figure 9

Thermogravimetric (TGA) spectra of rGO and GAg nanocomposites.

Figure 10

Bactericidal activity of PHA, PHA/rGO, and PHA/GAg against test organisms. PHA/rGO and PHA/GAg showed significant (p value <0.05) bactericidal effects towards Escherichia coli (a), and Staphylococcus aureus (b). p values were determined using a two-sample t-test distribution, (*) is <0.05; (**) is <0.01; and (***) is <0.001. The result presented was the average of three different batches of as-spun scaffolds of each nanocomposites (PHA, PHA/rGO and PHA/GAg.