Fabrication, biofunctionalization, and simultaneous multicolor emission of hybrid "dots-on-spheres" structures for specific targeted imaging of cancer cells

We report a simple technique for the fabrication of dots-on-spheres (DoS) structures in which conjugated polymer dots (CPdots) are immobilized on the surface of silica spheres via charged interaction. Red-, green-, and blue-emissive conjugated polymers were synthesized and employed to validate the feasibility of an approach to develop a DoS system with emission across the visible range. The robust binding of CPdots to silica particles provides a buffer resistance and good stability to photoirradiation and mechanical agitation. Further bioconjugation of the DoS system is achieved by the introduction of polyarginine and neu antibody that is specific for the HER2 receptor, leading to their successful application to targeted imaging of SKBR-3 breast cancer cells overexpressing HER2. Moreover, DoS with simultaneous multicolor emissions of red, green, and blue can be easily synthesized and used to demonstrate the versatility of this strategy for multicolor cellular imaging based upon a single excitation source. We believe that this hybrid DoS strategy and the easy fabrication of organic polymer nanoparticles with silica substrates will facilitate their effective integration of organic and inorganic materials into versatile applications.