Water‐Soluble Poly(N‐isopropylacrylamide)–Graphene Sheets Synthesized via Click Chemistry for Drug Delivery

Abstract

Covalently functionalized graphene sheets are prepared by grafting a welldefi ned thermo-responsive poly( N -isopropylacrylamide) (PNIPAM) via click chemistry. The PNIPAM-grafted graphene sheets (PNIPAM-GS) consist of about 50% polymer, which endows the sheets with a good solubility and stability in physiological solutions. The PNIPAM-GS exhibits a hydrophilic to hydrophobic phase transition at 33 ° C, which is relatively lower than that of a PNIPAM homopolymer because of the interaction between graphene sheets and grafted PNIPAM. Moreover, through π --π stacking and hydrophobic interaction between PNIPAM-GS and an aromatic drug, the PNIPAM-GS is able to load a water-insoluble anticancer drug, camptothecin (CPT), with a superior loading capacity of 15.6 wt-% (0.185 g CPT per g PNIPAM-GS). The in vitro drug release behavior of the PNIPAM-GS-CPT complex is examined both in water and PBS at 37 ° C. More importantly, the PNIPAM-GS does not exhibit a practical toxicity and the PNIPAM-GS-CPT complex shows a high potency of killing cancer cells in vitro. The PNIPAM-GS is demonstrated to be an effective vehicle for anticancer drug delivery.

Improved properties of chemically modified graphene/poly(methyl methacrylate) nanocomposites via a facile in-situ bulk polymerization

“…Therefore, chemical interaction via direct coupling between polymers and the surface groups bound on GO sheets [20][21][22][23][24][25][26] and grafting some molecules including monomer [27] and atom transfer radical polymerization (ATRP) initiator [28][29][30][31][32][33] prior to polymerization could be accomplished. Pan et al [25] prepared covalently functionalized graphene sheets by grafting a well defined thermo-responsive poly(N-isopropylacrylamide) via click chemistry and the nanocomposites exhibited a hydrophilic to hydrophobic phase transition at 33°C and a superior anticancer drug loading capacity of 15.6 wt%. Fang et al [30] covalently grafted an ATRP initiator onto the graphene sheet via a diazonium addition and the resulting polystyrene nano composites showed around 70 and 57% increases in tensile strength and Young's modulus with 0.9 wt% graphene nanosheets, respectively.…”

The Preparation of Graphene Oxide and Its Derivatives and Their Application in Bio-Tribological Systems

“…In recent years, many research papers concerning non-covalent functionalization of GO have been published and have provide great value to the study of graphene and GO-based materials for different applications [78][79][80][81][82][83][84].…”

Chemical functionalization of graphene oxide for improving mechanical and thermal properties of polyurethane composites

“…One feasible and effective strategy to promote the reinforcement of composites is through chemical functionalization of nanofillers [20][21][22]. Among chemical functionalization methods, grafting molecules and/or polymer chains onto the surface of graphene sheets was studied for many polymers [23][24][25].…”