Nanodiamonds to Help Target Cancer Cells

The use of nanoparticles (NPs) in biomedicine is an area of active research. Scientists are using biomimetic functionalisation strategies that could lead to targeted drug delivery with greater specificity and no toxicity.

Nanodiamond particles, or nanodiamonds (NDs), have emerged as a promising candidate for use in biomedical imaging and for different biomedical applications such as drug carrier platform. They show decreased cytotoxicity in comparison to other NPs, and can follow their fate by fluorescence imaging as a result of point defects in the diamond structure.

The EU-funded scientists have shown recently that mannose-coated NDs have exceptionally strong anti-adhesive behaviour for E. Coli adhesion, setting a new anti-adhesive strategy against E. Coli derived infections (Nanoscale, 2013). The EU-funded project 'Fabrication of particles with photoreceptors: Bio-analytical application such as controlled drug delivery' (PHOTORELEASE) was established to develop a novel strategy for the release of drugs and for the prevention of bacterial infections. It is based on the use of a photocleavable chemical linker between the drug or the molecules of interest and the NDs surface, while retaining the biological and chemical activity of the linked molecules.

Work has progressed extremely well, enabling synthesis of the photolinker (PL), surface functionalisation of the NDs and subsequent attachment of the linker. Before proceeding to drug trials, investigators covalently bonded enzyme horseradish peroxidase (HRP) as a model molecule to the ND–PL particles. They then monitored its photochemically activated release as a colorimetric change through formation of the blue oxidation product of HRP's activity on its substrate.

In parallel, scientists investigated the possibility of preparing glycan-coated NDs and assessed their stability in the presence of enzymes that cleave the carbohydrate moieties (glycosidases). Modification of the complexes with carbohydrates promises to increase specificity to cells of bacteria and lectins. Preliminary data suggest that glycan modification of NDs can affect their recognition ability not only by proteins that bind specific sugars (lectins) but also by glycosidases, an aspect not considered until now.

PHOTORELEASE is thus developing novel photochemical triggered release and delivery platforms of biological and biomedical interests. During the next project phase, investigators will study integration and release of drugs against cancer.

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