Biomaterials have long been used in the orthopaedic surgery to guide and assist bone repair. Nowadays, they also have the potential of being used as substrates for bone tissue engineering. Bioglasses like 45S5 present optimal bioactivity, but when sinterized into 3D monoliths they crystallize and partly loose their properties, mainly in vivo absorb ability. We have developed a novel bioglass, called ICIE16/BSG-NITRI, that not only overcomes this limitation but also displays improved reactivity and biocompatibility due to surface nitridation. ICIE16/SBG-NITRI was synthesized from a mixture of two melt-derived glasses through combined gel casting and foam replication techniques, followed by nitridation. It is highly porous but mechanically stable and mimics the architecture of bone tissue. Nitridation confers it improved reactivity and bioactivity facilitating its resorption and deposition of apatite (bone-like mineral) at its surface. The nitrided surface also improved its interaction with bone cells, which were found to attach better to ICIE16/SBG-NITRI and to differentiate earlier on its surface.
Figure legend: bone on the left and our ICIE16/BSG-Nitru bioglass on the right (in both cases bar is 500 µm).
Figure legend: merge of visible and fluorescent-blue channels to show cell distribution on the bioglass surface. The hoechst-stained nuclei can be seen as blue dots.
Orgaz F1, Dzika A1, Szycht O1, Amat D2,3, Barba F1, Becerra J3,4,5, Santos-Ruiz L3,4,5.[expand title=”Show Affiliations”]
1 Instituto de Cerámica y Vidrio, Consejo Superior de Investigaciones Científicas (ICV-CSIC), c/ Kelsen n° 5, 28049 Madrid, Spain
2 Universidad de Málaga, Departamento de Anatomía y Medicina Legal, Facultad de Medicina, Campus de Teatinos, 29071 Málaga, Spain
3 Centro de Investigación Biomédica en Red. Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Instituto de Salud Carlos III, c/ Monforte de Lemos 3-5, Pabellón 11, Planta 0, 28029 Madrid, Spain
4 Universidad de Málaga & IBIMA, Departamento de Biología Celular, Genética y Fisiología, Facultad de Ciencias, Campus de Teatinos, 29071 Málaga, Spain
5 BIONAND-Universidad de Málaga, c/ Severo Ochoa 35, Campanillas, 29590 Málaga, Spain [/expand]
Novel bioactive amorphous glass-glass composite scaffolds (ICIE16/BSG) with interconnected porosity have been developed. Hierarchically interconnected porous glass scaffolds were prepared from a mixture of two melt-derived glasses: a ICIE16 bioactive glass that was previously developed by Wu et al. (2011) to prevent crystallization, and a borosilicate glass of composition 73.48 SiO2-11.35 B2O3-15.15 Na2O (wt%). The resulting melt derived glass-glass composite scaffolds (ICIE16/BSG) were subject to surface functionalization to further improve its interaction with biological systems. Surface functionalization was performed by a nitridation process with hot gas N2/ammonia at 550°C for 2h, obtaining the ICIE16/BSG-NITRI. Evaluation of the degradation rate and the conversion to hydroxyapatite after immersion in simulated body fluid predicted a good biological activity of all the scaffolds, but particularly of the nitrided ones. In vitro evaluation of osteoblastic cells cultured onto the nitrided and non-nitrided scaffolds showed cell attachment, proliferation and differentiation on all scaffolds, but both proliferation and differentiation were improved in the nitrided ICIE16/BSG-NITRI.
STATEMENT OF SIGNIFICANCE:
Biomaterials are often required in the clinic to stimulate bone repair. We have developed a novel bioglass (ICIE16/SBG-NITRI) that can be sintered into highly porous 3D scaffolds, and we have further improved its bioactivity by nitridation. ICIE16/SBG-NITRI was synthesized from a mixture of two melt-derived glasses through combined gel casting and foam replication techniques, followed by nitridation. To mimic bone, it presents high-interconnected porosity while being mechanically stable. Nitridation improved its reactivity and bioactivity facilitating its resorption and the deposition of apatite (bone-like mineral) on its surface and increasing its degradation rate. The nitrided surface also improved the bioglass’ interaction with bone cells, which were found to attach better to ICIE16/SBG-NITRI and to differentiate earlier on its surface.
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