title: Surface Properties and MC3T3-E1 Cell Response of Cortical Bone Allografts Modified with Low-Concentration Phosphoric Acid.
abstract: OBJECTIVE
  This experimental study aimed to evaluate the effect of low-concentration phosphoric acid on the surface structure of cortical allografts.
  
  
  METHODS
  Allogenic cortical bones were obtained from femurs and tibias of New Zealand white rabbits. The bones were modified by treatment with various concentrations of phosphoric acid (10%, 20% or 30%) for 10, 30 or 60 minutes, then evaluated by the following methods: 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and LIVE/DEAD assay, alkaline phosphatase (ALP) assay, biomechanical properties testing, contact angle detection, quantitative real-time polymerase chain reaction (Q-PCR), western blotting and scanning electron microscopy (SEM).
  
  
  RESULTS
  Compared with the other groups, the group modified with 10% H3PO4 for 10 minutes had lower cytotoxicity according to MTT and LIVE/DEAD assays, higher hydrophilicity in the contact angle detection test and greater stability in the biomechanical properties test. Moreover, an up-regulation of osteopontin (OPN) in bones modified with 10% H3PO4 was observed by Q-PCR and western blotting. In addition, ALP assay and SEM showed that surface porosity and osteoinductivity were increased in the group modified with 10% H3PO4.
  
  
  CONCLUSIONS
  Low-concentration phosphoric acid may be a potential method for surface modification of cortical allografts. Further animal experiments and animal infection model studies are required to validate the efficacy of surface-modified cortical allografts to repair large segmental bone defects.
authors.affiliation: Department of orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Zengfa
authors.initials: Z
authors.lastname: Huang
authors.affiliation: Department of orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Cheng
authors.affiliation: Department of orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Wei
authors.affiliation: Department of orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Xianzhe
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Xinxin
authors.initials: X
authors.lastname: Yan
authors.affiliation: Department of orthopedics, Suining Municipal Hospital of Traditional Chinese Medicine, Suining, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Department of orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Yunlu
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Shuhua
authors.initials: S
authors.lastname: Yang
mesh_terms: D064591:Allografts; D000818:Animals; D016025:Bone Transplantation / Q000379:methods*; D002460:Cell Line; D005269:Femur / Q000378:metabolism / Q000637:transplantation*; D051379:Mice; D010756:Phosphoric Acids / Q000494:pharmacology*; D011817:Rabbits; D013977:Tibia / Q000378:metabolism / Q000637:transplantation*
chemical_list: D010756:Phosphoric Acids; C030242:phosphoric acid
keywords: Cortical allograft; Large segmental bone defect; Low-concentration phosphoric acid; Osteopontin.; Surface structure