title: Biocompatibility of pristine graphene for neuronal interface.
abstract: OBJECTIVE
  Graphene possesses unique electrical, physical, and chemical properties that may offer significant potential as a bioscaffold for neuronal regeneration after spinal cord injury. The purpose of this investigation was to establish the in vitro biocompatibility of pristine graphene for interface with primary rat cortical neurons.
  
  
  METHODS
  Graphene films were prepared by chemical vapor deposition on a copper foil catalytic substrate and subsequent apposition on bare Permanox plastic polymer dishes. Rat neuronal cell culture was grown on graphene-coated surfaces, and cell growth and attachment were compared with those on uncoated and poly-d-lysine (PDL)-coated controls; the latter surface is highly favorable for neuronal attachment and growth. Live/dead cell analysis was conducted with flow cytometry using ethidium homodimer-1 and calcein AM dyes. Lactate dehydrogenase (LDH) levels-indicative of cytotoxicity-were measured as markers of cell death. Phase contrast microscopy of active cell culture was conducted to assess neuronal attachment and morphology.
  
  
  RESULTS
  Statistically significant differences in the percentage of live or dead neurons were noted between graphene and PDL surfaces, as well as between the PDL-coated and bare surfaces, but there was little difference in cell viability between graphene-coated and bare surfaces. There were significantly lower LDH levels in the graphene-coated samples compared with the uncoated ones, indicating that graphene was not more cytotoxic than the bare control surface. According to phase contrast microscopy, neurons attached to the graphene-coated surface and were able to elaborate long, neuritic processes suggestive of normal neuronal metabolism and morphology.
  
  
  CONCLUSIONS
  Further use of graphene as a bioscaffold will require surface modification that enhances hydrophilicity to increase cellular attachment and growth. Graphene is a nanomaterial that is biocompatible with neurons and may have significant biomedical applications.
authors.affiliation: Department of Neurosurgery, Baylor College of Medicine, Houston, TX, USA.
authors.forename: Deshdeepak
authors.initials: D
authors.lastname: Sahni
authors.forename: Andrew
authors.initials: A
authors.lastname: Jea
authors.forename: Javier A
authors.initials: JA
authors.lastname: Mata
authors.forename: Daniela C
authors.initials: DC
authors.lastname: Marcano
authors.forename: Ahilan
authors.initials: A
authors.lastname: Sivaganesan
authors.forename: Jacob M
authors.initials: JM
authors.lastname: Berlin
authors.forename: Claudio E
authors.initials: CE
authors.lastname: Tatsui
authors.forename: Zhengzong
authors.initials: Z
authors.lastname: Sun
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Luerssen
authors.forename: Shiyun
authors.initials: S
authors.lastname: Meng
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Kent
authors.forename: James M
authors.initials: JM
authors.lastname: Tour
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001672:Biocompatible Materials; D002448:Cell Adhesion; D018929:Cell Culture Techniques / Q000379:methods*; D049109:Cell Proliferation; D002470:Cell Survival; D005434:Flow Cytometry; D006108:Graphite; D007770:L-Lactate Dehydrogenase / Q000032:analysis; D009474:Neurons / Q000201:enzymology; D051381:Rats
chemical_list: D001672:Biocompatible Materials; D006108:Graphite; D007770:L-Lactate Dehydrogenase