Self-Assembly of Conjugated Polymer on Hybrid Nanospheres for Cellular Imaging Applications

A new kind of hybrid core-shell nanosphere was fabricated by combining the in situ formation of Au nanoparticles and covalent cross-linking of biocompatible carboxymethyl starch dialdehyde (CMSD) and chitosan (CTS). When the fluorescent dye poly[9,9'-bis(6″-(N,N,N-trimethylammonium)-hexyl)fluorene-2,7-ylenevinylene-co-alt-1,4-phenylene dibromide] (PFV) was assembled on the surface of the hybrid nanospheres through electrostatic attraction, these biocompatible hybrid nanospheres exhibited metal-enhanced fluorescence effects. The fluorescence intensity of (CTS-Au)@CMSD/PFV hybrid nanosphere is 1.43 times that of CTS-CMSD/PFV hybrid nanospheres lacking Au nanoparticle. In addition, the (CTS-Au)@CMSD/PFV hybrid nanospheres exhibit excellent biodegradability upon exposure to enzymatic aqueous solution and good biocompatibility when cocultured with HeLa cervical carcinoma cells; these advantages make them attractive for cellular imaging and biological analysis and detection.