Biocompatible and Antimicrobial Electrospun Membranes Based on Nanocomposites of Chitosan/Poly (Vinyl Alcohol)/Graphene Oxide

Abstract

Tissue engineering is gaining attention rapidly to replace and repair defective tissues in the human body after illnesses and accidents in different organs. Electrospun nanofiber scaffolds have emerged as a potential alternative for cell regeneration and organ replacement. In this paper, porous membranes, based on nanofibrous chitosan (CS), polyvinyl alcohol (PVA), and graphene oxide (GO), were obtained via electrospinning methodology. Three different formulations were obtained varying GO content, being characterized by Fourier Transform Infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). In vitro tests were carried out, consisting of hydrolytic degradation inside simulated biological fluid (SBF), and in vivo tests were carried out, where the material was implanted in Wistar rats' subcutaneous tissue to determine its biocompatibility. The antibacterial activity was tested against Gram-positive bacteria Bacillus cereus and Staphylococcus aureus, and against Gram-negative Salmonella enterica and Escherichia coli, by contact of the electrospun nanofiber scaffolds above inoculum bacterial in Müeller Hinton agar with good inhibition only for scaffolds with the higher GO content (1.0%). The results confirmed good biocompatibility of the nanofibrous scaffolds after in vivo tests in Wistar rats, which evidences its high potential in applications of tissue regeneration.

Keywords: antibacterial nanofibrous membranes; chitosan; electrospinning; graphene oxide; polyvinyl alcohol.

Figure 1

Attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) of electrospun chitosan (CS)/polyvinyl alcohol (PVA)/graphene oxide (GO) composite nanofibrous membranes with different GO amounts (0%, 0.5%, and 1.0%).

Figure 2

SEM images of electrospun CS/PVA/GO composite nanofibrous membranes with different GO amounts (0%, 0.5%, and 1.0%). Images (A,C,E) at 500×, and images (B,D,F) at 10,000×. For all the experiments, the voltage used was 20 kV.

Figure 3

Weight loss of electrospun CS/PVA/GO composite nanofibrous membranes with different GO amounts (0%, 0.5%, and 1.0%), after several periods of immersion in a simulated biological fluid SBF.

Figure 4

Change in pH in the SBF after several days of immersion of the electrospun CS/PVA/GO composite nanofibrous membranes with different GO amounts (0%, 0.5%, and 1.0%).

Figure 5

SEM images of the electrospun CS/PVA/GO composite nanofibrous membranes after fourteen days in the degradation process in SBF. (A,B) 0% GO, (C,D) 0.5% GO, and (E,F) 1.0 % GO. Images (A,C,E) at 500×, and images (B,D,F) at 10,000×. For all the experiments, the voltage used was 20 kV.

Figure 6

The dorsal area of the rat Wistar after 30 days of the implantation: (A) hair recovery, (B) absence of injuries and infections, and (C) internal surface of the skin where the implanted samples are encapsulated by scar tissue.

Figure 7

Image of the control sample using the hematoxylin and eosin technique. Image (A) at 4× and image (B) at 10×. E: epidermis, D: dermis, AT: adipose tissue, BV: blood vessel, SCT: subcutaneous cellular tissue, and M: muscle.

Figure 8

Scaffold with 0% GO using the hematoxylin and eosin technique. Image (A) at 4× and image (B) at 10×. D: dermis, AT: adipose tissue, BV: blood vessel, SCT: subcutaneous cellular tissue, II: inflammatory infiltrate, IZ: implantation area, M: muscle, and FC: fibrous capsule.

Figure 9

Scaffold with 0.5% GO using the hematoxylin and eosin technique. Image (A) at 4× and image (B) at 10×. D: dermis, AT: adipose tissue, SCT: subcutaneous cellular tissue, II: inflammatory infiltrate, IZ: implantation area, and M: Muscle.

Figure 10

Scaffold with 1% GO using the hematoxylin and eosin technique. Image (A) at 4× and image (B) at 10×, Image (C) at 40×. D: dermis, AT: adipose tissue, II: inflammatory infiltrate, S: scaffold, IZ: implantation area, and M: muscle.