Acrylic Bone Cements Modified with Graphene Oxide: Mechanical, Physical, and Antibacterial Properties

Abstract

Bacterial infections are a common complication after total joint replacements (TJRs), the treatment of which is usually based on the application of antibiotic-loaded cements; however, owing to the increase in antibiotic-resistant microorganisms, the possibility of studying new antibacterial agents in acrylic bone cements (ABCs) is open. In this study, the antibacterial effect of formulations of ABCs loaded with graphene oxide (GO) between 0 and 0.5 wt.% was evaluated against Gram-positive bacteria: Bacillus cereus and Staphylococcus aureus, and Gram-negative ones: Salmonella enterica and Escherichia coli. It was found that the effect of GO was dependent on the concentration and type of bacteria: GO loadings ≥0.2 wt.% presented total inhibition of Gram-negative bacteria, while GO loadings ≥0.3 wt.% was necessary to achieve the same effect with Gram-positives bacteria. Additionally, the evaluation of some physical and mechanical properties showed that the presence of GO in cement formulations increased wettability by 17%, reduced maximum temperature during polymerization by 19%, increased setting time by 40%, and increased compressive and flexural mechanical properties by up to 17%, all of which are desirable behaviors in ABCs. The formulation of ABC loading with 0.3 wt.% GO showed great potential for use as a bone cement with antibacterial properties.

Keywords: acrylic bone cement; antibacterial activity; graphene oxide; mechanical properties; physical properties.

Figure 1

Photographs of the liquid phase of the acrylic bone cements’ (ABCs) formulations. From left to right, the percentage of graphene oxide (GO) increases from 0 to 0.5 wt.%.

Figure 2

Results characterization of GO. (a) Fourier transform infrared (FTIR) spectrum, (b) Dynamic light scattering (DLS), and (c) Peak deconvolution of C(1s) in the X-ray photoelectron spectra (XPS) of the graphene oxide.

Figure 3

FTIR spectra of ABCs loading with different percentages of GO. (a) Spectrum from 700 to 4000 cm⁻¹ and (b) spectrum from 3600 to 3900 cm⁻¹.

Figure 4

Thermogravimetric analysis (TGA) and Derivate-TGA(DTGA) thermograms of ABCs loading with different percentages of GO.

Figure 5

SEM images of the fractured surface of samples to the compression test of ABC modified with GO. (500×). (a) ABC 0% GO, (b) ABC 0.1% GO, (c) ABC 0.2% GO, (d) ABC 0.3% GO, and (e) ABC 0.5% GO.

Figure 6

Scanning electron microscope (SEM) images of ABC with 0.5 wt.% GO, where the GO sheets are shown in the cement at different magnifications. (a) 25,000× and (b) 10,000×.

Figure 7

Photographs of water contact angle (WCA) on the surfaces of ABC with different percentages of GO. (a) ABC 0% GO, (b) ABC 0.1% GO, (c) ABC 0.2% GO, (d) ABC 0.3% GO, and (e) ABC 0.5% GO. Asterisks denote significant differences of ABC loading samples respect to ABC 0% GO at a significance levels of * p < 0.05 and ** p < 0.01.

Figure 8

Handling parameters of liquid–powder mixture in ABC loadings with GO. (a) The maximum temperature reaches during the polymerization and (b) setting time of each formulation.The red dash line indicates the minimum value of the property set in ISO 5833-02 [21]. Asterisks denote significant differences of ABC loading samples with respect to ABC 0% GO at a significant level of * p < 0.05.

Figure 9

Mechanical properties compression and bending in ABC modified with different percentages of GO. (a) Compressive strength, (b) compressive modulus, (c) bending strength, and (d) bending modulus. The red dash line indicates the minimum value of the property set in ISO 5833-02 [21]. Asterisks denote significant differences of modified ABC samples respect to ABC 0% GO at significance levels of * p < 0.05 and ** p < 0.01.

Figure 10

Storage modulus and tangent delta de ABC modified with GO obtained by dynamic mechanical analysis (DMA).

Figure 11

Colony-forming units (CFU) of Gram-positive (a) and Gram-negative strains (b) after 24 h incubation with GO-modified ABCs. Asterisks denote significant differences of ABC loading samples with respect to ABC 0% GO at significance levels of * p < 0.05 and ** p < 0.01.