New bioactive, osteointegrative strontium-substituted apatite cements for bone regeneration
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1
National Research Council, Institute of Science and Technology for Ceramics, Italy
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2
Università Cattolica del Sacro Cuore, Orthopaedics and Traumatology, Italy
Introduction: Injectable biomaterials addressed to bone healing are a subject of major interest and intense investigation, as they can be delivered by mini-invasive surgery and, thanks to ability of self-hardening in situ, may adequately stabilize bone fractures or voids due to trauma or tumour. Particular interest is also addressed to vertebral fractures, due to trauma or osteoporosis-related bone weakening, mainly treated with vertebroplasty procedures since decades[1],[2]. However, complete bone regeneration still remains an unsolved clinical need, mainly due to the lack of bone cements endowed with suitable bioactivity, osteoconductivity and bio-resorption ability. In this respect there is an ever growing interest on calcium phosphate bone cements (CPCs), due to their excellent biocompatibility and chemical similarity with bone tissue[3]. In the present work Sr-doped hydroxyapatite (HA) cements were synthesized by a novel approach, where a unique inorganic precursor prepared by high temperature solid state synthesis was associated with a bio-erodible sodium alginate to improve physical cohesion and osteoconductivity in vivo. The obtained cements were subjected to robust chemico-physical, morphological, mechanical and biological in vitro and in vivo characterization.
Experimental: Sr-substituted αTCP powders with different strontium content were synthesized by solid state reaction at 1400 °C then adequately processed to improve surface reactivity and mixed with the setting solution. Physico-chemical characterization was performed by means of X-ray diffraction, SEM, ion release and compressive strength. In vitro tests were performed to evaluate cell behaviour in respect to the strontium content. In vivo tests were carried out by implantation in critical size defect in rabbit femur, in comparison with a polymer-free commercial CPC (KyphOs FS™, Medtronic Spine LLC, Minneapolis, MN, USA).
Results and Discussion: The new cement exhibited short setting time and mechanical strength adequate for loading, stable after 1 month of ageing at physiological conditions. The cement was able to release strontium ions in cell culture media that can account for improved cell behaviour in comparison with strontium-free cements. Preliminary in vivo tests demonstrated good osteogenesis and enhanced bone penetration, in respect to the control.
Conclusions: Strontium-substituted apatitic cements enriched with alginate proved promising features as novel injectable biomaterial enabling fast osseointegration and regeneration of mature bone.
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The research leading to these results has received funding from the PNR-CNR Aging Program 2012-2014
References:
[1] M. Bohner M, Injury 2000;31 Suppl 4: 37-47.
[2] D.G. Poitout Biomechanics and Biomaterials in Orthopedics. 2004. Springer.
[3] M.P. Ginebra, C. Canal, M. Espanol, D. Pastorino, E.B. Montufar, Adv Drug Deliv Rev 2012;64: 1090-1110.
Keywords:
Bone Regeneration,
in vivo,
Calcium phosphate,
Cell response
Conference:
10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016.
Presentation Type:
Poster
Topic:
Biomaterials in musculoskeletal orthopeadics and tissues
Citation:
Sprio
S,
Dapporto
M,
Panseri
S,
Montesi
M,
Logroscino
G and
Tampieri
A
(2016). New bioactive, osteointegrative strontium-substituted apatite cements for bone regeneration.
Front. Bioeng. Biotechnol.
Conference Abstract:
10th World Biomaterials Congress.
doi: 10.3389/conf.FBIOE.2016.01.00649
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Received:
27 Mar 2016;
Published Online:
30 Mar 2016.