title: A novel photocrosslinkable and cytocompatible chitosan coating for Ti6Al4V surfaces.
abstract: BACKGROUND
  In this work, chitosan (CH) was used to produce a novel coating for Ti6Al4V, the most widely used alloy in orthopedic implants, so as to improve the biological tissue response at the metallic surface.
  
  
  METHODS
  The Ti6Al4V surface was sandblasted with alumina particles. CH was chemically modified, via carbodiimide chemistry, using lactobionic and 4-azidebenzoic acid to make it soluble at physiological pH and photocrosslinkable, respectively. The reaction was verified by FTIR, NMR and UV/vis spectroscopy. Ti6Al4V surfaces were coated with solutions of the modified CH and exposed to UV light, causing polymer crosslinking and formation of a hydrogel on the surface. The crosslinking reaction was monitored by FTIR at different exposure times. Coating morphology was observed by SEM. The coating's cytocompatibility was determined in vitro through the culture of rat bone marrow mesenchymal stem cells, using an MTT assay, with their morphology assessed by SEM.
  
  
  RESULTS
  The developed coating behaved as a hydrogel on the Ti6Al4V and was stable on the surface. FTIR and NMR confirmed the crosslinking mechanism, based on an arile ring expansion, and subsequent reaction with the CH amine groups. Furthermore, the coating was able to support cell proliferation and osteogenic differentiation.
  
  
  CONCLUSIONS
  UV crosslinking of CH is easy to apply and has potential for future metallic implant surface modifications. Due to its nature as a hydrogel, the coating could be used for further studies in the encapsulation of bioactive molecules to improve osteogenic potential at the tissue-implant interface.
authors.affiliation: Human Tissue Engineering Laboratory, Health Sciences, Institute of Advanced Studies (IDEA), Sartenejas Valley, Caracas - Venezuela.|Department of Materials Science, Simon Bolivar University, Sartenejas Valley, Caracas - Venezuela.
authors.forename: Denise
authors.initials: D
authors.lastname: Zujur
authors.affiliation: Human Tissue Engineering Laboratory, Health Sciences, Institute of Advanced Studies (IDEA), Sartenejas Valley, Caracas - Venezuela.
authors.forename: Josnell
authors.initials: J
authors.lastname: Moret
authors.affiliation: Human Tissue Engineering Laboratory, Health Sciences, Institute of Advanced Studies (IDEA), Sartenejas Valley, Caracas - Venezuela.
authors.forename: Dubrasvka
authors.initials: D
authors.lastname: Rodriguez
authors.affiliation: Human Tissue Engineering Laboratory, Health Sciences, Institute of Advanced Studies (IDEA), Sartenejas Valley, Caracas - Venezuela.
authors.forename: Lauren
authors.initials: L
authors.lastname: Cruz
authors.affiliation: Department of Materials Science, Simon Bolivar University, Sartenejas Valley, Caracas - Venezuela.
authors.forename: Joaquin
authors.initials: J
authors.lastname: Lira
authors.affiliation: Center for Biomaterials and Corrosion, National Experimental University "Antonio Jose de Sucre" (UNEXPO), Puerto Ordaz, Bolivar State - Venezuela.
authors.forename: Linda
authors.initials: L
authors.lastname: Gil
authors.affiliation: Department of Traumatology, Uyapar Hospital, Puerto Ordaz, Bolivar State - Venezuela.
authors.forename: Ernic
authors.initials: E
authors.lastname: Dominguez
authors.affiliation: Human Tissue Engineering Laboratory, Health Sciences, Institute of Advanced Studies (IDEA), Sartenejas Valley, Caracas - Venezuela.|State University of Milagro, National Secretary of Higher Education, Science and Technology, Prometeo Project - Ecuador.
authors.forename: Jose
authors.initials: J
authors.lastname: Alvarez-Barreto
mesh_terms: D000497:Alloys; D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D048271:Chitosan / Q000737:chemistry*; D020099:Coated Materials, Biocompatible / Q000737:chemistry* / Q000494:pharmacology / Q000633:toxicity; D003432:Cross-Linking Reagents / Q000737:chemistry* / Q000494:pharmacology / Q000633:toxicity; D008297:Male; D059630:Mesenchymal Stem Cells; D051381:Rats; D017207:Rats, Sprague-Dawley; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
chemical_list: D000497:Alloys; D020099:Coated Materials, Biocompatible; D003432:Cross-Linking Reagents; C031462:titanium alloy (TiAl6V4); D048271:Chitosan; D014025:Titanium