Graphene-Based Composites for Biomedical Applications: Surface Modification for Enhanced Antimicrobial Activity and Biocompatibility

Abstract

The application of graphene-based materials in medicine has led to significant technological breakthroughs. The remarkable properties of these carbon materials and their potential for functionalization with various molecules and compounds make them highly attractive for numerous medical applications. To enhance their functionality and applicability, extensive research has been conducted on surface modification of graphene (GN) and its derivatives, including modifications with antimicrobials, metals, polymers, and natural compounds. This review aims to discuss recent and relevant studies related to advancements in the formulation of graphene composites, addressing their antimicrobial and/or antibiofilm properties and evaluating their biocompatibility, with a primary focus on their biomedical applications. It was concluded that GN surface modification, particularly with compounds intrinsically active against bacteria (e.g., antimicrobial peptides, silver and copper nanomaterials, and chitosan), has resulted in biomaterials with improved antimicrobial performance. Furthermore, the association of GN materials with non-natural polymers provides composites with increased biocompatibility when interfaced with human tissues, although with slightly lower antimicrobial efficacy. However, it is crucial to highlight that while modified GN materials hold huge potential, their widespread use in the medical field is still undergoing research and development. Comprehensive studies on safety, long-term effects, and stability are essential before their adoption in real-world medical scenarios.

Keywords: antimicrobial activity; biocompatibility; biomedical applications; graphene-based materials; surface modification.

Figure 1

Schematic representation of the antibacterial mechanisms of GN and factors influencing its antimicrobial activity. (1) Penetration and disruption of the bacterial cell membrane with consequent leakage of the intracellular content; (2) oxidative stress with (a) and without (b) generation of reactive oxygen species (ROS); (3) bacteria wrapping/trapping.

Figure 2

Types of graphene (GN) modifications discussed in this review for potential use in the biomedical field.

Figure 3

Scanning electron microscope (SEM) images of (a) Salmonella enteritidis bacteria and (b) S. enteritidis growing on silver nanoparticles (AgNPs)-graphene oxide (GO)-coated nanoplatform. Reprinted with permission from Ref. [55]. Copyright 2019 The Authors.

Figure 4

Escherichia coli and Bacillus subtilis exposed to (a) graphene oxide (GO), (b) polyoxyalkyleneamine (POAA)-GO, and (c) chitosan (CS)-GO for 3 h and characterized by transmission electron microscopy (TEM). Reprinted with permission from Ref. [67]. Copyright 2018 The Authors.

Figure 5

Antibiofilm capability of graphene (GN) and usnic acid (UA)-loaded graphene films against Staphylococcus aureus and Staphylococcus epidermidis. Representative fluorescence microscopic images from Live/Dead staining of staphylococcal biofilms. Reprinted with permission from Ref. [75]. Copyright 2021 The Authors.