title: Polymer surface adsorption as a strategy to improve the biocompatibility of graphene nanoplatelets.
abstract: The biointeractions of graphene-based materials depend on their physico-chemical properties. These properties can be manipulated by polymer adsorption. Graphene nanoplatelets (GNP-C) were modified with PVA, HEC, PEG, PVP, chondroitin, glucosamine, and hyaluronic acid. These materials were characterized by SEM, DLS, XPS, Raman spectroscopy, and TGA. Surface adsorption was confirmed for all polymers. Biocompatibility evaluation showed that all of these materials induced low haemolysis (<1.7%) at concentrations up to 500μgmL(-1). GNP-C-PVA and GNP-C-HEC presented the lowest haemolysis percentages and were therefore more thoroughly studied. The morphology of HFF-1 cells was investigated by microscopy (optical, fluorescence, TEM) in order to evaluate interactions with GNP materials. Small GNP-C nanoplatelets were observed to enter cells independently of the surface treatment. For pristine GNP-C at a concentration of 50μgmL(-1), ROS production increased 4.4-fold. This effect is lower for GNP-C-PVA (3.3-fold) and higher for GNP-C-HEC (5.1-fold). Resazurin assays showed that GNP-C caused toxicity in HFF-1 cells at concentrations above 20μgmL(-1) at 24h, which decreased at 48 and 72h. PVA surface adsorption rendered GNP-C non-toxic at concentrations up to 50μgmL(-1). LIVE/DEAD assays showed that at 20 and 50μgmL(-1) cell death is significantly lower for GNP-C-PVA compared to pristine GNP-C. Modification of nanoplatelets with HEC resulted in no benefit in terms of biocompatibility, whereas PVA considerably improved the biocompatibility.
authors.affiliation: LEPABE - Laboratory for Process, Environment, Biotechnology and Energy Engineering, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; INEB - National Institute of Biomedical Engineering, University of Porto, Rua do Campo Alegre, 823, 50-180 Porto, Portugal; i3S - Institute for Innovation and Health Research, University of Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal.
authors.forename: Artur M
authors.initials: AM
authors.lastname: Pinto
authors.affiliation: IFIMUP and IN - Institute of Nanoscience and Nanotechnology, Department of Physics and Astronomy, Faculty of Sciences, University of Porto, Rua do Campo Alegre 687, 4169-007, Porto, Portugal.
authors.forename: J Agostinho
authors.initials: JA
authors.lastname: Moreira
authors.affiliation: LEPABE - Laboratory for Process, Environment, Biotechnology and Energy Engineering, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal. Electronic address: fdmagalh@fe.up.pt.
authors.forename: Fernão D
authors.initials: FD
authors.lastname: Magalhães
authors.affiliation: INEB - National Institute of Biomedical Engineering, University of Porto, Rua do Campo Alegre, 823, 50-180 Porto, Portugal; i3S - Institute for Innovation and Health Research, University of Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal.
authors.forename: Inês C
authors.initials: IC
authors.lastname: Gonçalves
mesh_terms: D000327:Adsorption; D001672:Biocompatible Materials / Q000737:chemistry*; D049109:Cell Proliferation; D002478:Cells, Cultured; D005347:Fibroblasts / Q000737:chemistry* / Q000166:cytology; D006108:Graphite / Q000737:chemistry*; D006461:Hemolysis; D006801:Humans; D049329:Nanostructures / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011142:Polyvinyl Alcohol; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D011108:Polymers; D006108:Graphite; D011142:Polyvinyl Alcohol
keywords: HEC; Hemocompatibility; Hydroxyethyl cellulose; PVA; Poly(vinyl alcohol); Surface modification; TEM