title: Structural changes and biological responsiveness of an injectable and mouldable monetite bone graft generated by a facile synthetic method.
abstract: Brushite (dicalcium phosphate dihydrate) and monetite (dicalcium phosphate anhydrous) are of considerable interest in bone augmentation owing to their metastable nature in physiological fluids. The anhydrous form of brushite, namely monetite, has a finer microstructure with higher surface area, strength and bioresorbability, which does not transform to the poorly resorbable hydroxyapatite, thus making it a viable alternative for use as a scaffold for engineering of bone tissue. We recently reported the formation of monetite cements by a simple processing route without the need of hydrothermal treatment by using a high concentration of sodium chloride in the reaction mix of β-tricalcium phosphate and monocalcium phosphate monohydrate. In this paper, we report the biological responsiveness of monetite formed by this method. The in vitro behaviour of monetite after interaction and ageing both in an acellular and cellular environment showed that the crystalline phase of monetite was retained over three weeks as evidenced from X-ray diffraction measurements. The crystal size and morphology also remained unaltered after ageing in different media. Human osteoblast cells seeded on monetite showed the ability of the cells to proliferate and express genes associated with osteoblast maturation and mineralization. Furthermore, the results showed that monetite could stimulate osteoblasts to undergo osteogenesis and accelerate osteoblast maturation earlier than cells cultured on hydroxyapatite scaffolds of similar porosity. Osteoblasts cultured on monetite cement also showed higher expression of osteocalcin, which is an indicator of the maturation stages of osteoblastogenesis and is associated with matrix mineralization and bone forming activity of osteoblasts. Thus, this new method of fabricating porous monetite can be safely used for generating three-dimensional bone graft constructs.
authors.affiliation: Biomaterials, Biomimetics and Biophotonics, King's College London Dental Institute, Floor 17, Tower Wing, Guy's Hospital, London Bridge, London SE1 9RT, UK.
authors.forename: G
authors.initials: G
authors.lastname: Cama
authors.affiliation: Biomaterials, Biomimetics and Biophotonics, King's College London Dental Institute, Floor 17, Tower Wing, Guy's Hospital, London Bridge, London SE1 9RT, UK.
authors.forename: B
authors.initials: B
authors.lastname: Gharibi
authors.affiliation: Division of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, 256 Gray's Inn Road, London WC1X 8LD, UK Department of Nanobiomedical Science and BK21 Plus NBM Global Research Centre for Regenerative Medicine, Dankook University, Cheonan 330-714, Republic of Korea.
authors.forename: J C
authors.initials: JC
authors.lastname: Knowles
authors.affiliation: Biomaterials, Biomimetics and Biophotonics, King's College London Dental Institute, Floor 17, Tower Wing, Guy's Hospital, London Bridge, London SE1 9RT, UK.
authors.forename: S
authors.initials: S
authors.lastname: Romeed
authors.affiliation: Biomaterials, Biomimetics and Biophotonics, King's College London Dental Institute, Floor 17, Tower Wing, Guy's Hospital, London Bridge, London SE1 9RT, UK.
authors.forename: L
authors.initials: L
authors.lastname: DiSilvio
authors.affiliation: Biomaterials, Biomimetics and Biophotonics, King's College London Dental Institute, Floor 17, Tower Wing, Guy's Hospital, London Bridge, London SE1 9RT, UK sanjukta.deb@kcl.ac.uk.
authors.forename: S
authors.initials: S
authors.lastname: Deb
mesh_terms: D018786:Bone Substitutes / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D002130:Calcium Phosphates / Q000737:chemistry*; D002478:Cells, Cultured; D016922:Cellular Senescence; D006801:Humans; D008422:Materials Testing; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism*
chemical_list: D018786:Bone Substitutes; D002130:Calcium Phosphates; C485829:calcium phosphate, dibasic, anhydrous; C494366:calcium phosphate, dibasic, dihydrate
keywords: bone defects; bone substitute; monetite