Hierarchical Self-Assembly of Responsive Organoplatinum(II) Metallacycle-TMV Complexes with Turn-On Fluorescence

Here we report that the rod-like tobacco mosaic virus (TMV), having a negatively charged surface, can be assembled into three-dimensional micrometer-sized bundle-like superstructures via multiple electrostatic interactions with a positively charged molecular "glue", namely, a tetraphenylethylene (TPE)-based discrete organoplatinum(II) metallacycle (TPE-Pt-MC). Due to the nanoconfinement effect in the resultant TMV/TPE-Pt-MC complexes and the aggregation-induced emission (AIE) activity of the TPE units, these hierarchical architectures result in a dramatic fluorescence enhancement that not only provides evidence for the formation of novel metal-organic biohybrid materials but also represents an alternative to turn-on fluorescence. Moreover, the dissociation of these final constructs and subsequent release of individual virus have been achieved by disrupting the TPE-Pt-MC core using tetrabutylammonium bromide (TBAB). This strategy is also compatible with other protein-based nanoparticles such as bacteriophage M13 and ferritin, proving the generality of this approach. Hence, this research will open new routes for the fabrication of functional biohybrid materials involving metal-organic complexes and anisotropically shaped bionanoparticles.