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Graphene-based hybrid nanomaterials are interestingly being considered in expanding fields such as supercapacitors, biosensors, biomedicine, and pathogen deactivation. Surface properties of the two-dimensional (2D) hybrids are crucial in dictating their safety and efficacy. Therefore, concise and accurate functionalization of the pristine 2D nanomaterials is very important for facilitating their clinical trials. In this case, some of the promising candidates for effective and controllable functionalization of graphene derivatives are dendrimers and hyperbranched polymers because of their high density of tunable functional moieties and their ability to interact with biosystems. Herein, we have reviewed recent advances on designing graphene-dendritic polymer hybrids and their applications together with the challenges in the field.

A new graphene oxide (GO)-based hydrogel was synthesized through cross-linking of biofunctionalized graphene oxide nanosheets by di-alkyne polyethylene glycol as cross-linking agent. In this respect, nitrene chemistry as a convenient and straightforward protocol was developed for biofunctionalization of GO using an azido-starch as an eco-friendly, biodegradable and cost-effective material. In the next step, 1,3-dipolar cycloaddition chemistry, a green and highly efficient approach was utilized in cross-linking of functionalized GO by PEG through click reaction between remaining azido groups of starch on the surface of GO sheets and terminal alkyne groups of polyethylene glycol. Formation of aziridine and triazole rings during functionalization and cross-linking in this method could evidently improve biological activities of the obtained hydrogel compared to the conventional methods. The antibacterial activity of the new compounds was explored. The synthesized hydrogel showed antibacterial properties against Gram-positive and Gram-negative bacteria due to the presence of triazole rings. Also, the resulting hydrogel exhibited high dye removal efficiency and it can be utilized in water treatment effectively. The adsorption kinetics was analyzed through the effects of adsorption time and the dye concentration on the adsorption capacity. Kinetic data were accurately described by a pseudo-second-order model.

In this work, we reported a facile method to produce stable aqueous graphene dispersion through direct exfoliation of graphite by modified hyperbranched polyglycerol. Size of graphene sheets was manipulated by simultaneous exfoliation and sonication of graphite, and functionalized graphene sheets with narrow size distribution were obtained. The polyglycerol-functionalized graphene sheets exhibited highly efficient cellular uptake and photothermal conversion, enabling it to serve as a photothermal agent for cancer therapy.

In this work, new class of supramolecular copolydendrimers (SCDs) consisting of polyamidoamines (PAMAMs) and polyglycerol were synthesized through host-guest interactions. SCDs were able to encapsulate, transport, and release doxorubicin (DOX) efficiently. Host-guest interactions between PAMAM and polyglycerol was depended on pH so that aqueous solutions of SCDs and SCDs-based drug delivery systems were stable at room temperature and pH = 7.4, but their building blocks were separated in lower pHs(

The increasing importance of nanotechnology in the field of biomedical applications has encouraged the development of new nanomaterials endowed with multiple functions. Novel nanoscale drug delivery systems with diagnostic, imaging and therapeutic properties hold many promises for the treatment of different types of diseases, including cancer, infection and neurodegenerative syndromes. Carbon nanotubes (CNTs) are both low-dimensional sp2 carbon nanomaterials exhibiting many unique physical and chemical properties that are interesting in a wide range of areas including nanomedicine. Since 2004, CNTs have been extensively explored as drug delivery carriers for the intracellular transport of chemotherapy drugs, proteins and genes. In vivo cancer treatment with CNTs has been demonstrated in animal experiments by several different groups. Herein, the recent works on anticancer drug delivery systems based on carbon nanotubes are reviewed and some of more specific and important novel drug delivery devices are discussed in detail. This paper focuses on modifications of CNTs by polymers through covalent and non-covalent attachments: two different methods as critical steps in preparation of anticancer drug delivery systems from CNTs. In this respect the in vivo and in vitro behaviors and toxicity of the CNTs modified by polymers are summarized as well. Well-functionalized CNTs did not show any significant toxicity after injection into mice. Moreover, administration and excretion of CNT-based nanocarriers are discussed. It was concluded that future development of CNT-based nanocarriers may bring novel opportunities to cancer diagnosis and therapy.

Polycitric acid was conjugated onto the surface of carbon nanotubes (CNTs), and hybrid nanomaterials containing CNT axis and polycitric acid branches that were highly soluble in aqueous solutions were synthesized. In this work, pristine MWCNTs were opened and functionalized through treatment with acid, then polycitric acid was covalently grafted onto their surface by the “grafting from” approach based on polycondensation of citric acid in the melting state. The chemical structure, morphology, thermal properties and size of MWCNT-g-PCA hybrid materials were investigated by IR, 13C NMR, 1H NMR, TEM, TGA, DSC and DLS. To investigate the biocompatibility of the synthesized hybrid nanomaterials and their potential applications for future nanomedicine, short-term in vitro cytotoxicity and hemocompatibility tests were conducted on HT1080 cell line (human fibrosarcoma). Based on the results of the in vitro cytotoxicity tests and hemolysis assay, no adverse effect was observed on the HT1080 cell and also on red blood cells up to 1 mg/mL concentration. It appeared that the changes in the conformation, shape and dispersity of CNTs, induced by the conjugated hyperbranched polymers, were the main factors that affected the toxicity of CNTs and also their interaction with the cell membranes. Interestingly, the results of the cytotoxicity tests were in agreement with our previous work, carbon nanotubes-graft-polyglycerol, proving that hyperbranched polymers conjugated onto the surface of CNTs dominated their physiochemical properties and therefore their interactions with the cell membranes.

New hybrid nanostructure-based magnetic drug delivery systems (HNMDDSs) consisting of carbon nanotubes, magnetic iron oxide nanoparticles, and linear-dendritic copolymers linked to anticancer drugs were synthesized and characterized. Polyamidoamine–polyethylene glycol–polyamidoamine (PAMAM–PEG–PAMAM) ABA type linear-dendritic copolymers were used to solubilize and functionalize carbon nanotubes through supramolecular chemistry. There are three key features of HNMDDSs: (a) use of functionalized MWCNTs as a biocompatible platform for the delivery of magnetic iron oxide nanoparticles, therapeutic drugs, and diagnostics, (b) use of PAMAM–PEG–PAMAM linear-dendritic copolymers as water soluble, biocompatible and high functional hybrid materials with a linear polyethylene glycol part which cause a high solubility for MWCNT through supramolecular interactions and dendritic PAMAM parts which cause a high functionality for MWCNT, (c) use of magnetic iron oxide nanoparticles as targeting, imaging, or hyperthermia cancer treatment agents. To prove the efficacy of synthesized HNMDDSs, they were subjected to the receptor-mediated endocytosis and release inside the cancer cells. Then, it was unambiguously proved that these tumor-targeting HNMDDSs are promising systems for future cancer therapy with low drug doses, thereby forming a solid foundation for further investigation and development. Multi-functional hybrid nanomaterials are promising systems to deliver anticancer agents to tumors. .

Metal-carbon nanotube-graft-polymer (MCNT-g-P) nanocomposites were synthesized and characterized successfully. In this work, multiwall carbon nanotubes (MWCNT) were opened using HNO3/H2SO4 mixture and filled by metal nanoparticles such as silver nanoparticles through wet chemistry method. Then MWCNT containing metal nanoparticles were used as macroinitiator for ring opening polymerization of e-caprolactone and MCNT-g-P nanocomposites were obtained. Length of grafted polymer arms onto the MWCNT was controlled using MWCNT/e-caprolactone ratio. Structure and properties of nanocomposites were evaluated by TEM, DSC, TGA, and spectroscopy methods.

Benzyl alcohol and Rose Bengal were loaded and entrapped using linear–dendritic macromolecules by two procedures. In the first procedure, benzyl alcohol was attached to the end functional groups of linear–dendritic macromolecules by ester bonds to afford linear–dendritic–host conjugates. In the second procedure, entrapment was based on physical interactions between Rose Bengal and linear–dendritic macromolecules; this procedure is known as complexation method. Loading and binding capacity of different linear–dendritic macromolecules was investigated using 1H nuclear magnetic resonance (NMR) and UV spectroscopy methods. It was found the loading or binding capacity of linear–dendritic macromolecules depends on their generation, so that higher generations have higher loading or binding capacity. Diameter of nanocarriers was investigated using dynamic light scattering (DLS) experiments, and it was between 16 and 50 nm for different nanocarriers. Release of guest molecules from nanocarriers was evaluated at pH 1, 7.4, and 10.

Dendritic core–shell architectures containing poly (glycerol) and poly (ethylene imine) cores and poly(lactide) shell (PG-PLA and PEI-PLA respectively) were synthesized. Analogous of these core–shell architectures containing the same cores but poly (L-lactide) shell (PG-PLLA and PEI-PLLA, respectively) were also synthesized. In this work PG and PEI were used as macroinitiator for ring opening polymerization of the lactid and L-lactide monomers. Different molar ratios of monomer to end functional groups of PG ([LA]/[OH]) and PEI ([LA]/[NHn] (n = 1 or 2)) were used to prepare the core–shell architectures with different shell thickness. These core–shell architectures were able to encapsulate and transport the small guest molecules. Their transport capacity (TC) depended on the type and thickness of the shells. TC of core–shell architectures containing PLLA shell was higher than that for their analogs containing PLA shell. The diameter of core–shell architectures was between 20–80 nm. The rate of release of guest molecules from chloroform solution of nanocarriers to water phase was investigated and it depended on the type of the core, shell and solvent.

Background and purpose of the study Carbon nanotubes (CNTs) are emerging drug and imaging carrier systems which show significant versatility. One of the extraordinary characteristics of CNTs as Magnetic Resonance Imaging (MRI) contrasting agent is the extremely large proton relaxivities when loaded with gadolinium ion (Gdn 3+) clusters. Methods In this study equated Gdn 3+ clusters were loaded in the sidewall defects of oxidized multiwalled (MW) CNTs. The amount of loaded gadolinium ion into the MWCNTs was quantified by inductively coupled plasma (ICP) method. To improve water solubility and biocompatibility of the system, the complexes were functionalized using diamine-terminated oligomeric poly (ethylene glycol) via a thermal reaction method. Results Gdn 3+ loaded PEGylated oxidized CNTs (Gdn 3+@CNTs-PEG) is freely soluble in water and stable in phosphate buffer saline having particle size of about 200 nm. Transmission electron microscopy (TEM) images clearly showed formation of PEGylated CNTs. MRI analysis showed that the prepared solution represents 10% more signal intensity even in half concentration of Gd3+ in comparison with commerciality available contrasting agent Magnevist®. In addition hydrophilic layer of PEG at the surface of CNTs could prepare stealth nanoparticles to escape RES. Conclusion It was shown that Gdn 3+@CNTs-PEG was capable to accumulate in tumors through enhanced permeability and retention effect. Moreover this system has a potential for early detection of diseases or tumors at the initial stages.