title: Reinforcement of injectable calcium phosphate cement by gelatinized starches.
abstract: Current injectable calcium phosphate bone cements (CPC) encounter the problems of low strength, high brittleness, and low cohesion in aqueous environment, which greatly hinder their clinical applications for loading-bearing bone substitution and minimally invasive orthopedic surgeries. Here, a strategy of using gelatinized starches to reinforce injectable CPC was investigated. Four types of starches, namely corn starch, crosslinked starch, cationic starch, and Ca-modified starch, were studied for their influence on CPC mechanical properties, injectability, setting times, anticollapsibility, and cytocompatibility. Gelatinized starch significantly improved compressive strength and modulus as well as strain energy density of CPC to different extents. Specifically, both corn starch and Ca-modified starch revealed sixfold and more than twofold increases in the compressive strength and modulus of CPC, respectively. The addition of gelatinized starches with proper contents increased the injectability and anticollapsibility of CPC. In addition, osteoblast proliferation tests on leaching solution of modified cements showed that gelatinized starches had no adverse effect on cell proliferation, and all cement samples resulted in better osteoblast proliferation compared to phosphate-buffered solution control. The mechanisms behind the reinforcing effect of different starches were preliminarily studied. Two possible mechanisms, reinforcement by the second phase of gelatinized starch and strong interlocking of apatite crystals, were proposed based on the results of starch zeta potential and viscosity, cement microstructure, and resultant mechanical properties. In conclusion, incorporating gelatinized starches could be an effective, facile, and bio-friendly strategy to reinforce injectable CPC and improve its mechanical stability, and thus, should be further studied and developed.
authors.affiliation: Department of Orthopaedics, Orthopaedic Institute, The First Affiliated Hospital, Soochow University, Suzhou, Jiangsu, 215006, People's Republic of China.
authors.forename: Huiling
authors.initials: H
authors.lastname: Liu
authors.affiliation: College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, Jiangsu, 215123, People's Republic of China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Guan
authors.affiliation: Department of Orthopaedics, Orthopaedic Institute, The First Affiliated Hospital, Soochow University, Suzhou, Jiangsu, 215006, People's Republic of China.
authors.forename: Donglei
authors.initials: D
authors.lastname: Wei
authors.affiliation: Department of Orthopaedics, Orthopaedic Institute, The First Affiliated Hospital, Soochow University, Suzhou, Jiangsu, 215006, People's Republic of China.
authors.forename: Chunxia
authors.initials: C
authors.lastname: Gao
authors.affiliation: Department of Orthopaedics, Orthopaedic Institute, The First Affiliated Hospital, Soochow University, Suzhou, Jiangsu, 215006, People's Republic of China.
authors.forename: Huilin
authors.initials: H
authors.lastname: Yang
authors.affiliation: Department of Orthopaedics, Orthopaedic Institute, The First Affiliated Hospital, Soochow University, Suzhou, Jiangsu, 215006, People's Republic of China.|The State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing, 100190, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Yang
mesh_terms: D000818:Animals; D001843:Bone Cements / Q000737:chemistry / Q000494:pharmacology; D002130:Calcium Phosphates / Q000737:chemistry / Q000494:pharmacology; D049109:Cell Proliferation / Q000187:drug effects; D005780:Gelatin / Q000737:chemistry / Q000494:pharmacology; D008422:Materials Testing; D051379:Mice; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism*; D013213:Starch / Q000737:chemistry / Q000494:pharmacology
chemical_list: D001843:Bone Cements; D002130:Calcium Phosphates; D005780:Gelatin; D013213:Starch; C020243:calcium phosphate
keywords: calcium phosphates; composite; injectable; mechanical properties; starches