Bioactive Glass/Gelatin Hybrid Biomaterials for Bone Tissue Engineering
Lallukka, Mari (2020)
2020
Biotekniikan DI-tutkinto-ohjelma - Degree Programme in Bioengineering, MSc (Tech)
Lääketieteen ja terveysteknologian tiedekunta - Faculty of Medicine and Health Technology
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Hyväksymispäivämäärä
2020-02-19
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202002182173
https://urn.fi/URN:NBN:fi:tuni-202002182173
Tiivistelmä
Hybrid biomaterials combining bioactive glasses (BAG) and natural polymers such as gelatin, are potential alternatives for bone tissue engineering applications. The inorganic and organic phases in a hybrid interact at a molecular scale and are connected via covalent bonds due to coupling agents such as 3-glycidoxypropyl trimethoxysilane (GPTMS). Owing to the strong covalent bonding between phases it is possible to create materials with controllable degradation (both aqueous and enzymatic), and bioactivity. Furthermore, the rheological properties of the materials can be adjusted to increase the mechanical properties and/or allow shaping of the hybrid into a specific shape.
In this study, hybrids with either silicate glass S53P4, or Mg and Sr-doped borosilicate glass B12.5 –Mg 5- Sr 10 (“mix”) combined to organic gelatin phase were synthesized with different weight ratios between phases: 30/70 (glass/gelatin), 15/85, 5/95 and 1/99. The aim of this study was to assess in vitro properties of these hybrid biomaterials. The bioactivity and degradation behaviour of the hybrids were investigated in Simulated Body Fluid (SBF) and in enzymatic collagenase solution. SBF dissolution experiment was carried out for two weeks, and enzymatic degradation experiment for six hours. At every time point, samples’ mass loss and ion release behaviour were studied, and SBF samples’ pH changes were measured.
For further characterization of the hybrids, rheological measurements were performed to understand the gelation behaviour of the hybrids, and thermogravimetric analysis (TGA) to assess the inorganic/organic phase ratio.
In addition, the biocompatibility of BAG/gelatin hybrid materials were evaluated by culturing human-derived mesenchymal stem cells (hBMSCs) in contact with hybrid samples and with hybrid dissolution product extracts. Furthermore, the ion concentrations in cell culturing medium upon culturing were also measured.
Based on the results, the hybrids were stable in aqueous solutions, and exhibited controlled ion release suggesting hydroxyapatite (HA) layer precipitation. The hybrids were also more resistant to enzymatic degradation than the gelatin alone. However, based on the Live/Dead results all hybrid compositions showed an inhibitory effect in hBMSC proliferation after 72 hours of culturing, possibly due to too high reactivity or release of unreacted compounds, such as the coupling agent GPTMS. Further cell studies and optimization of the hybrid biomaterial are needed to confirm the suitability of hybrids as a biocompatible bone tissue engineering scaffold material
In this study, hybrids with either silicate glass S53P4, or Mg and Sr-doped borosilicate glass B12.5 –Mg 5- Sr 10 (“mix”) combined to organic gelatin phase were synthesized with different weight ratios between phases: 30/70 (glass/gelatin), 15/85, 5/95 and 1/99. The aim of this study was to assess in vitro properties of these hybrid biomaterials. The bioactivity and degradation behaviour of the hybrids were investigated in Simulated Body Fluid (SBF) and in enzymatic collagenase solution. SBF dissolution experiment was carried out for two weeks, and enzymatic degradation experiment for six hours. At every time point, samples’ mass loss and ion release behaviour were studied, and SBF samples’ pH changes were measured.
For further characterization of the hybrids, rheological measurements were performed to understand the gelation behaviour of the hybrids, and thermogravimetric analysis (TGA) to assess the inorganic/organic phase ratio.
In addition, the biocompatibility of BAG/gelatin hybrid materials were evaluated by culturing human-derived mesenchymal stem cells (hBMSCs) in contact with hybrid samples and with hybrid dissolution product extracts. Furthermore, the ion concentrations in cell culturing medium upon culturing were also measured.
Based on the results, the hybrids were stable in aqueous solutions, and exhibited controlled ion release suggesting hydroxyapatite (HA) layer precipitation. The hybrids were also more resistant to enzymatic degradation than the gelatin alone. However, based on the Live/Dead results all hybrid compositions showed an inhibitory effect in hBMSC proliferation after 72 hours of culturing, possibly due to too high reactivity or release of unreacted compounds, such as the coupling agent GPTMS. Further cell studies and optimization of the hybrid biomaterial are needed to confirm the suitability of hybrids as a biocompatible bone tissue engineering scaffold material