Facile fabrication of glycosylated and PEGylated carbon nanotubes through the combination of mussel inspired chemistry and surface-initiated ATRP.

Surface modification of carbon nanotubes (CNTs) through controlled living polymerization has demonstrated to be a useful route for preparation of CNTs based polymer composites. However, surface oxidation of CNTs is often required to generate functional groups, which can be further utilized for immobilization of polymerization initiator and grafting polymers. The surface oxidation procedure is rather complex, high energy cost, low efficient and will destroy the structure of CNTs. Therefore, the development of simple and efficient strategies for preparation of CNTs based composites should be of great research interest and raised much attention recently. In this work, a novel mussel inspired strategy that combination of ATRP and ring-opening reaction has been developed for simultaneous preparation of glycosylated and PEGylated CNTs for the first time. CNTs were first coated with polydopamine (PDA) through self-polymerization of dopamine under alkaline aqueous solution. Then polymerization initiator was immobilized on CNT-PDA through simple esterification and amidation reaction to obtain CNT-PDA-Br. The PEGylated CNTs were synthesized through ATRP using CNT-PDA-Br as initiator and polyethylene glycol monoester acrylate and itaconic anhydride (IA) as the monomers. Finally, glucosamine was conjugated with IA via ring-opening reaction. The successful preparation of glycosylated and PEGylated CNTs (CNT-PDA-Poly(PEGMA-co-IA)-Glu) was confirmed by a number of characterization techniques in details. The obtained CNTs based composites showed improved aqueous dispersibility and desirable cytocompatibility, implying their biomedical application potential. As compared with the conventional covalent strategies, the mussel inspired method described in this work will not destroy the structure for introduction functional groups on the surface of CNTs, that can occur under rather mild experimental conditions, including room temperature, short reaction time and aqueous solution. On the other hand, the mussel inspired chemistry can also be used for surface modification of almost any materials regardless of their size, morphology and compositions. Therefore, we believe that the mussel inspired strategy should be a general method for fabrication of various polymer composites for different applications.