Self-assembled graphene-dextran nanohybrid for killing drug-resistant cancer cells

Polysaccharide nano-vesicular multidrug carriers for synergistic killing of cancer cells

Multi-drug delivery based on polymer nano-scaffolds is an essential protocol to be developed for better administration of anticancer drugs to enhance their therapeutic efficacies against cancer cells. Here, we report dual delivery polysaccharide nano-vesicles that are capable of loading and delivering both water soluble and water insoluble drugs together in a single polymer scaffold. The selective rupture of the nano-vesicular assembly under intracellular enzyme conditions allowed the simultaneous delivery of a hydrophobic drug camptothecin (CPT) and hydrophilic drug doxorubicin (DOX) supporting their synergistic killing of breast and colon cancer cells. The polysaccharide nano-vesicles have allowed us to address a few important questions regarding the need for multiple drug administration in cancer cells including (a) the role of simultaneous drug release, (b) antagonistic versus synergistic effects of drug combinations and (c) how these are affected by the ratio of drugs. Further, evaluation of the role of caveolae in endocytosis of these polymer scaffolds was also made. The vesicular scaffolds were found to preserve and deliver DOX resulting in 50-60% better killing of cancer cells than the free drug. Additionally, dual loaded nano-vesicles when compared to drug cocktails with individual drugs in separate nano-vesicles (at comparable molar ratios) suggest the relative drug concentration following release and mode of delivery to be both important in cancer cell killing. Results from these experiments have revealed newly developed polysaccharide nano-vesicles loaded with DOX and CPT drugs as potential candidates for improved breast cancer cell killing. Thus, these custom-designed polysaccharide nano-vesicles provide a new perspective on multi-anticancer drug delivery systems and their efficacy.

Surface engineering of graphene-based nanomaterials for biomedical applications

Graphene-based nanomaterials have attracted tremendous interest over the past decade due to their unique electronic, optical, mechanical, and chemical properties. However, the biomedical applications of these intriguing nanomaterials are still limited due to their suboptimal solubility/biocompatibility, potential toxicity, and difficulties in achieving active tumor targeting, just to name a few. In this Topical Review, we will discuss in detail the important role of surface engineering (i.e., bioconjugation) in improving the in vitro/in vivo stability and enriching the functionality of graphene-based nanomaterials, which can enable single/multimodality imaging (e.g., optical imaging, positron emission tomography, magnetic resonance imaging) and therapy (e.g., photothermal therapy, photodynamic therapy, and drug/gene delivery) of cancer. Current challenges and future research directions are also discussed and we believe that graphene-based nanomaterials are attractive nanoplatforms for a broad array of future biomedical applications.

Intracellular pH-sensitive metallo-supramolecular nanogels for anticancer drug delivery

For drug delivery systems, the most important factors are biocompatibility and stability. To achieve excellent biocompatibility, learning from naturally occurring systems may be the best choice. Herein, a series of pH-sensitive metallo-supramolecular nanogels (MSNs) were prepared by the metallo-supramolecular coordinated interaction between histidine and iron-meso-tetraphenylporphin, which mimicks the way that hemoglobin carries oxygen. With the excellent biocompatibility and special supramolecular pH sensitivity, MSNs had been exploited to load and release anticancer drug doxorubicin (DOX). In vitro drug release profiles showed that only a small amount of the loaded DOX was released in PBS solution at pH 7.4, while up to about 80% of the loaded DOX could be quickly released at pH 5.3 due to the pH-dependent disassembly of MSNs. Confocal laser scanning microscopy (CLSM) and flow cytometry were used to verify the cellular uptake and intracellular drug release behaviors of DOX-loaded MSNs toward MCF-7. Efficient cellular proliferation inhibition against MCF-7 and HeLa cells was also observed by a 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. These features suggested that MSNs could be of great potential as intelligent drug delivery systems.