title: Calcium phosphate fibers coated with collagen: In vivo evaluation of the effects on bone repair.
abstract: The aim of this study was to assess the characteristics of the CaP/Col composites, in powder and fiber form, via scanning electron microscopy (SEM), pH and calcium release evaluation after immersion in SBF and to evaluate the performance of these materials on the bone repair process in a tibial bone defect model. For this, four different formulations (CaP powder - CaPp, CaP powder with collagen - CaPp/Col, CaP fibers - CaPf and CaP fibers with collagen - CaPf/Col) were developed. SEM images indicated that both material forms were successfully coated with collagen and that CaPp and CaPf presented HCA precursor crystals on their surface. Although presenting different forms, FTIR analysis indicated that CaPp and CaPf maintained the characteristic peaks for this class of material. Additionally, the calcium assay study demonstrated a higher Ca uptake for CaPp compared to CaPf for up to 5 days. Furthermore, pH measurements revealed that the collagen coating prevented the acidification of the medium, leading to higher pH values for CaPp/Col and CaPf/Col. The histological analysis showed that CaPf/Col demonstrated a higher amount of newly formed bone in the region of the defect and a reduced presence of material. In summary, the results indicated that the fibrous CaP enriched with the organic part (collagen) glassy scaffold presented good degradability and bone-forming properties and also supported Runx2 and RANKL expression. These results show that the present CaP/Col fibrous composite may be used as a bone graft for inducing bone repair.
authors: Department of Biosciences, Federal University of São Paulo (UNIFESP), Santos, SP, Brazil.
authors: Fabio Roberto
authors: FR
authors: Ueno
authors: Department of Biosciences, Federal University of São Paulo (UNIFESP), Santos, SP, Brazil.
authors: Hueliton Wilian
authors: HW
authors: Kido
authors: Department of Biosciences, Federal University of São Paulo (UNIFESP), Santos, SP, Brazil.
authors: Renata Neves
authors: RN
authors: Granito
authors: Department of Biosciences, Federal University of São Paulo (UNIFESP), Santos, SP, Brazil.
authors: Paulo Roberto
authors: PR
authors: Gabbai-Armelin
authors: Department of Biosciences, Federal University of São Paulo (UNIFESP), Santos, SP, Brazil.
authors: Angela Maria Paiva
authors: AM
authors: Magri
authors: Department of Biosciences, Federal University of São Paulo (UNIFESP), Santos, SP, Brazil.
authors: Kelly Rosseti
authors: KR
authors: Fernandes
authors: Nuclear and Energy Research Institute (IPEN), São Paulo, SP, Brazil.
authors: Antonio Carlos
authors: AC
authors: da Silva
authors: Nuclear and Energy Research Institute (IPEN), São Paulo, SP, Brazil.
authors: Francisco José Correa
authors: FJ
authors: Braga
authors: Department of Biosciences, Federal University of São Paulo (UNIFESP), Santos, SP, Brazil.
authors: Ana Claudia Muniz
authors: AC
authors: Renno
mesh_terms: D000818:Animals; D001861:Bone Regeneration; D018786:Bone Substitutes / Q000737:chemistry*; D002130:Calcium Phosphates / Q000737:chemistry*; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D003094:Collagen / Q000737:chemistry*; D008297:Male; D017208:Rats, Wistar; D013977:Tibia / Q000293:injuries* / Q000502:physiology* / Q000648:ultrastructure
chemical_list: D018786:Bone Substitutes; D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; D003094:Collagen; C020243:calcium phosphate
keywords: Composite; bone repair; calcium phosphate; collagen; fibers