# Recent Advances in the Synthesis of Graphene-Based Nanomaterials for Controlled Drug Delivery
## 4 Conclusions and Perspectives  
In summary, we demonstrated various ways of drug delivery with different nanomaterials and the recent typical studies on the synthesis of graphene-based nanomaterials for controlled drug delivery. It is clear that graphene-based nanomaterials play important roles in improving the drug loading and release performances. In addition, when some other nanoscale building blocks, like small molecules, nanoparticles, polymers, DNA, proteins, and peptides were modified onto graphene or GO, both biological properties and drug delivery function could be enhanced to a great extent. Due to the unique structure (2D, monolayer) and properties (high stability, good conductivity, easy modification) of graphene, the facile synthesis of novel graphene-based nanomaterials will extend biomedical applications in the future.  
In the last years, a large amount of studies on the drug delivery application with graphene-based nanomaterials have been reported, but there are still some aspects that should be further focused on. First, more synthesis methods of monolayer graphene (GO and RGO) and the subsequent biomolecular  
Figure 9: Schematic illustration of (**a**) core-shell protein-graphene-protein (PGP) capsules encapsulating hydrophilic doxorubicin; and (**b**) the mechanism of cancer therapy of PGP capsules under near-infrared irradiation (NIR). Reproduced with permission from [85], [PERSON] [PERSON], 2014.  
modifications with proteins, peptides, DNA, and others could be developed. The monolayered graphene-based bio-nanohybrids will show interesting results for drug delivery, biosensing, and tissue engineering. Second, the long-period biocompatibility and cellular toxicity of graphene-based nanomaterials should be investigated. Third, the biological interactions between graphene and cells, tissues, or organs should be studied in depth to understand the cellular uptake mechanisms, such as [PERSON] et al., and [PERSON] et al., found that the pristine graphene and GO can induce cytotoxicity through the depletion of the mitochondrial membrane potential and the increase of intracellular reactive oxygen species, and then trigger apoptosis by activation of the mitochondrial pathway [88; 89], respectively. Finally, as most of studies are currently focused on the delivery of drug for cancer cells, it is possible to utilize graphene-based nanomaterials for the detection and therapy of other diseases such as Parkinson's, Alzheimer's, HIV, and others. For example, previously [PERSON] and co-workers have reported that graphene could destruct the formation of amyloid fibrils [90], which provides a potential idea for designing graphene-based anti-Alzheimer's drugs.  
[PERSON] thanks the financial supports from the national natural science foundation of China (No. 21407004) and natural science foundation of Anhui province (Nos. 1508085 QB48, KJ2017A345). [PERSON] and [PERSON] acknowledge the supports from the Deutsche Forschungsgemeinschaft (DFG) under grants WE 5837/1-1 ([PERSON]) and CI 144/2 ([PERSON]).  
[PERSON] and [PERSON] proposed and organized the contents of this review. [PERSON] and [PERSON] wrote the paper. [PERSON] and [PERSON] made revisions on the manuscript.  
The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results.