Buckyballs meet Viral Nanoparticles – Candidates for Biomedicine

摘要

Fullerenes such as C60 show promise as functional components in several emerging technologies. For biomedical applications, C60 has been used in gene- and drug-delivery vectors, as imaging agents, and as photosensitizers in cancer therapy. A major drawback of C60 for bioapplications is its insolubility in water. To overcome this limitation, we covalently attached C60 derivatives to Cowpea mosaic virus and bacteriophage Qβ virus-like particles, as examples of naturally occurring viral nanoparticle (VNP) structures that have been shown to be promising candidates for biomedicine. Two different labeling strategies were employed, giving rise to water-soluble and stable VNP-C60 and VNP-PEG-C60 conjugates. Samples were characterized using a combination of transmission electron microscopy, scanning transmission electron microscopy (STEM), gel electrophoresis, size-exclusion chromatography, dynamic light scattering, and western blotting. “Click” chemistry bioconjugation using a PEG-modified propargyl-O-PEG-C60 derivative gave rise to high loadings of fullerene on the VNP surface, indicated by the imaging of individual C60 units by STEM. The cellular uptake of dye-labeled VNP-PEG-C60 complexes in a human cancer cell line was found by confocal microscopy to be robust, showing that cell internalization was not inhibited by the attached C60 units. These results open the door for the development of novel therapeutic devices with potential applications in photo-activated tumor therapy.