Chemoselective modification of turnip yellow mosaic virus by Cu(I) catalyzed azide-alkyne 1,3-dipolar cycloaddition reaction and its application in cell binding.

Turnip yellow mosaic virus (TYMV) is an icosahedral plant virus with a diameter of 28-30 nm that can be isolated in gram quantities from turnip or Chinese cabbage inexpensively. In this study, TYMV combined with spatially addressable surface chemistries was selected as a prototype bionanoparticle for modulating patterns of cell adhesion, morphology, and proliferation. We exploited the chemical reactivity of TYMV using the mild conditions of Cu(I) catalyzed azide-alkyne cycloaddition (CuAAC) reaction, the best example of "click" chemistry. Oligo-ethylene glycol (OEG) short chain, coumarintriazole, and RGD-containing peptide were grafted on the surface of TYMV via carbodiimide activation and CuAAC reaction. The bioconjugation to intact viral particles was confirmed by MS, TEM, FPLC, and SDS-PAGE with fluorescence visualization analysis. Therefore, this method is a generally useful means of incorporating various types of functionalities onto the TYMV surface. Further studies were done to learn the behavior of NIH-3T3 fibroblast cells on the modified or unmodified TYMV surfaces. OEG-modified TYMV surfaces retarded cell attachment and growth, while cell adhesion, spreading, and proliferation were dramatically enhanced on RGD-modified TYMV surfaces. Compared with RGD immobilized 3-aminopropyltriethoxysilane-coated glass surface, the cells are more ready to spread fully and proliferate on TYMV-RGD coated surface, which thus provides a more cell-friendly environment with nanometer-scale surface features. This illustrates the potential application of plant virus based materials in tissue engineering, drug delivery, and biosensing.