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 b-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.

Gold is for the mistress, silver for the maid: Enhanced mechanical properties, osteoinduction and antibacterial activity due to iron doping of tricalcium phosphate bone cements

“…[1,2,3,4] Although hydroxyapatite is the calcium phosphate most similar to the mineral component of natural bone, having decent mechanical properties too [5], it is poorly resorbed in the body and different calcium phosphates have been preferred to it, more resorbable and capable of inducing a more optimal bone regeneration process. Among these resorbable calcium phosphates, monetite and brushite are the currently favourite candidates [6,7]. However, although calcium phosphates present ideal bone tissue substitutes from the standpoints of bioactivity and biocompatibility, their state-of-the-art, self-setting formulations suffer from (a) weak mechanical properties, (b) negligible bone growth gene effects without the use of exogenous growth factors, and (c) a lack of intrinsic antibacterial activity.…”

A structural approach in the study of bones: fossil and burnt bones at nanosize scale

“…In fact the treatment of bone defects (i.e. bone deficiency because of trauma, tumour or infections) represents a challenge for orthopaedic surgeons owing to lack of therapeutic approaches that are able to fully restore the lost bone, and brushite cements have 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 raised in the last few years special interest because they are resorbed in vivo much faster than bioapatite ones due to their metastable nature in physiological fluids [49][50].…”

Bioactive monetite‐containing whisker‐like fibers reinforced chitosan scaffolds

“…It is believed that the brushite is sometimes associated with the formation of HA within the material, which led to decrease the degradation rate as a result of the lower solubility of HA. Monetite is of special interest as it can promote bone formation, owing to its high degradation rate under physiological conditions . Monetite granules implanted in human alveolar defects have formed a higher amount of newly formed bone than HA granules, due to its more resorbability, providing both bone growth space, and ions (calcium and phosphate) for formation of new bone .…”

“…It is reported that the monetite particles were transferred to carbonated apatite when immersed in simulated body fluid (SBF) or cell culture medium (α‐MEM) . In contrast, monetite ceramics in another cell culture media known as Dulbecco's modified Eagle's media (DMEM) with and without cell seeding showed that the crystal structure of monetite was not changed after 3 weeks …”