GO-COO-HP-β-CD nanosphere: a complex construction and its drug-loading properties

Novel controlled drug release system engineered with inclusion complexes based on carboxylic graphene

A novel drug carrier is constructed by compositing hydrophilic hydroxypropyl-β-cyclodextrins (HP-β-CD) and carboxylated graphene nanomaterial (GO-COOH). Fourier transform infrared spectroscopy confirms that the two materials are successfully combined via chemical bonds. Further, a crosslinking agent of glutaraldehyde is applied to fabricate composite GO-COO-HP-β-CD nanospheres, as demonstrated by an atomic force microscope. Dexamethasone (DEX) is selected as the model drug, and the drug loading efficiency and water solubility of the nanospheres greatly increased. Additionally, the achieved DEX/nanosphere inclusion complex exhibits better heat resistance compared with pure DEX, which is a desired property for drug processing. More importantly, different models are applied to different releasing durations to investigate in detail the release profile of DEX. The best fitting release kinetics model is given to reveal the release mechanism of the drug delivery system. The highest hemolysis rate of the DEX/nanosphere inclusion is 0.44%, far lower than the standard of 5% delivered by the American Society for Testing and Materials, ensuring its safety in practical applications. Meanwhile, recalcification tests indicate that DEX/nanosphere retains the normal blood coagulation function. In vitro cytotoxicity tests of the inclusion demonstrate that the nanospheres have no toxicity and are qualified for intravenous applications with good blood compatibility. Finally, the bioactivity of DEX after release from the carriers is investigated. Results corroborate that the drug anti-inflammation efficacy is not affected and that the biomedical function can be well retained. The engineered controlled drug release system represents a promising formulation platform for a broad range of therapeutic medicine in pharmaceutical technology.

Recent developments in the synthesis and applications of graphene-family materials functionalized with cyclodextrins

The introduction of cyclodextrin species to graphene-family materials (GFMs) constitutes an important area of research, especially in terms of the development of applied nanoscience. The chemistry of cyclodextrins is the so-called host-guest chemistry, which has impacted on many fields of research, including catalysis, electrochemistry and nanomedicine. Cyclodextrins are water-soluble and biocompatible supramolecules, and therefore they may introduce new interesting properties to GFMs and may enhance the physicochemical/biological features of native GFMs. The reported methods for the conjugation of cyclodextrins to GFMs utilize either covalent or non-covalent approaches. The recent progress in the applications of GFMs functionalized with cyclodextrins, with the respect to the chemistry and features of these conjugates, is discussed. Special consideration is also given to the recent developments in (i) nanomedicine, (ii) electrochemistry, (iii) adsorption and (iv) catalysis. Examples of these materials are discussed in this work, together with the future outlook on the impact of GFM-cyclodextrin conjugates in the development of applied nanoscience.

Near-infrared light-mediated photodynamic/photothermal therapy nanoplatform by the assembly of Fe3O4 carbon dots with graphitic black phosphorus quantum dots

Background

Recently, combined photodynamic therapy (PDT) and photothermal therapy (PTT) has become a desired treatment for cancer. However, the development of economic, high-efficiency, and safe photosensitizers/photothermal agents remains a significant challenge.

Methods

A novel nanocomposite has been developed via the assembly of iron oxide carbon dot (Fe₃O₄-CDs) nanoparticles and black phosphorus quantum dots (genipin [GP]-polyglutamic acid [PGA]-Fe₃O₄-CDs@BPQDs), and this nanocomposite shows a broad light-absorption band and a photodegradable character.

Results

In vitro and in vivo assays indicated that GP-PGA-Fe₃O₄-CDs@BPQDs were highly biocompatible and exhibited excellent tumor-inhibition efficacy, due to the synergistic PTT and PDT via a near-infrared laser. Importantly, in vivo tumor magnetic resonance imaging (MRI) results illustrated that GP-PGA-Fe₃O₄-CDs@BPQDs can be specifically applied for enhanced T₂ MRI of tumors. This work presents the first combined application of a PDT and PTT effect deriving from BPQDs and MRI from Fe₃O₄-CDs, which may promote utilization of black BPQDs in biomedicine.

Conclusion

As expected, GP-PGA-Fe₃O₄-CDs@BPQDs displayed a dramatically enhanced ability to destroy tumor cells, due to the synergistic combination of PTT and PDT.

Synthesis of novel cyclodextrin-modified reduced graphene oxide composites by a simple hydrothermal method

Cyclodextrin (β-CD)-functionalized reduced graphene oxide was successfully synthesized by a simple hydrothermal method, followed by conjugating with polyethylene glycol (PEG) and folic acid (FA). Microscopic and spectroscopic techniques were used to characterize the nanocomposites. Photothermal experiments showed that β-CD-functionalized reduced graphene oxide exhibited higher photothermal conversion efficiency in the near infrared region than reduced graphene oxide functionalized with other molecules under the same conditions. Cytotoxicity experiments indicated that rGO@CD@PEG@FA possessed good biocompatibility even at high concentration. When doxorubicin (DOX) was loaded on the rGO@CD@PEG@FA nanocomposite, it showed the stimulative effect of heat, pH response, and sustained drug release. Cytotoxicity experiments also confirmed the targeted effect and high efficiency of the combined therapy. The findings of the present study provide an ideal drug delivery system for malignant cancer therapy due to the advanced synergistic chemo-photothermal targeted therapy and good drug release properties.

The rGO@CD@PEG@FA nanocomposite showed the stimulative effect of heat, pH response, and sustained drug release for cancer therapy