# Graphene-Based Functional Hybrid Membranes for Antimicrobial Applications: A Review
## 6 Conclusions and Outlook  
In conclusion, in this review, we comprehensively and systemically summarize the synthesis and functional tailing of graphene-based membranes, as well as their applications in antimicrobial fields. From the above introduction and discussion, it can be concluded that macroscopic graphene-based membranes can be successfully synthesized by traditional techniques such as CVD, vacuum-assisted filtration, spin-coating, drop-casting, and LBL self-assembly. The addition of other functional nanomaterials such as metals, metal oxide, polymers, biomolecules, and biopolymers, enables the functional regulation of graphene-based membrane materials with an improved antimicrobial performance, and the nanocomposite-based hybrid membranes can overcome the limitations of individual component-based graphene membranes. The graphene-based functional membranes exhibit excellent antibacterial, antiviral and antifungal effects. In addition, we introduce the mechanisms of graphene-based membranes for antimicrobial resistance, which are crucial to guide the design and fabrication of graphene-based membranes for biomedical applications.  
Although great achievements have been made regarding the antimicrobial applications of graphene-based membranes in recent years, it is necessary for researchers to develop novel techniques and materials to promote the development of this promising research topic. First, it is necessary to modify graphene materials with highly active biomolecules such as antimicrobial biopolymers and antimicrobial peptides to enhance the biological properties of graphene-based membranes. The addition of these biomolecules could improve the biocompatibility and antimicrobial performances of graphene-based membranes. Second, the fabrication techniques of 2D graphene membranes should be developed for large-scale production, with a low cost and high sustainability, as these are highly required for practical applications in biomedical and other fields. Third, graphene-based new materials should be studied to improve and optimize the performance of graphene-based hybrid membranes, which are expected to only show toxicity to the microorganisms, but reveal high biocompatibility with human cells, to realize the next generation of the most advantageous antimicrobial materials. Fourth, other 2D materials, such as transition metal oxides, MXenes, metal-organic frameworks (MOFs), and others could be utilized to fabricate functional 2D membranes for antimicrobial applications, which could lead to surprising findings and effects in the future.  
Conceptualization, G.W. and H.K.; software, X.Z. and H.K.; resources, X.Z. and H.K.; data curation, X.Z., G.Y., D.Z., X.L. and P.H.; writing--original draft preparation, X.Z. and H.K.; writing--review and editing, X.Z., H.K. and G.Y.; supervision, H.K. and G.W.; project administration, G.W.; funding acquisition, G.W. All authors have read and agreed to the published version of the manuscript.  
The authors thank the financial support from the National Natural Science Foundation of China (No. 51873225), the Taishan Scholars Program of Shandong Province (No. tsqn201909104), and the High-Grade Talents Plan of Qingdao University. This work is partly supported by the Innovation and Entrepreneurship Program for College Students of Qingdao University.  
Not applicable.  
The authors acknowledge the Endnote editing support by [PERSON] and [PERSON] (Qingdao University).  
The authors declare no conflict of interest.