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Inspired by the mineralization process of bone, we have investigated mineralization on piezoelectric samples immersed in a solution with mineral ions. We have utilized polyvinylidene fluoride as a piezoelectric material and 10× simulated body fluid as a mineral solution. Three synthetic material systems were developed and characterized using scanning electron microscopy, X-ray diffraction, nanoindentation, and scratch testing. With these techniques, we provide insights into how the characteristics of the mineralization protocol affect the microstructure, chemical composition, crystal structure, and mechanical properties of the minerals. Increasing the solution temperature from 25°C to 50°C resulted in a greater packing density, roughly 10 times the stiffness and 4 times the fracture toughness. Collagen surface treatment resulted in roughly 7 times the stiffness along with potential anisotropy in the fracture toughness. Lastly, calcium phosphate minerals appear to pack in low-density and high-density phases on the piezoelectric scaffolds.
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Equilibrium interactions of biomimetic DNA aptamers produce intrafibrillar calcium phosphate mineralization of collagen
Native and biomimetic DNA structures have been demonstrated to impact materials synthesis under a variety of conditions but have only just begun to be explored in this role compared to other biopolymers such as peptides, proteins, polysaccharides, and glycopolymers. One selected DNA aptamer has been explored in calcium phosphate and calcium carbonate mineralization, demonstrating sequence-dependent control of kinetics, morphology, and crystallinity. This aptamer is here applied to a biologically-relevant bone model system that uses collagen hydrogels. In the presence of the aptamer, intrafibrillar collagen mineralization is observed compared to negative controls and a positive control using well-studied poly-aspartic acid. The mechanism of interaction is explored through affinity measurements, kinetics of calcium uptake, and kinetics of aptamer uptake into the forming mineral. There is a marked difference observed between the selected aptamer containing a G-quadruplex secondary structure compared to a control sequence with no G-quadruplex. It is hypothesized that the equilibrium interaction of the aptamer with calcium-phosphate precursors and with the collagen itself leads to slow kinetic mineral formation and a morphology appropriate to bone. This points to new uses for DNA aptamers in biologically-relevant mineralization systems and the possibility of future biomedical applications.
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- Award ID(s):
- 1904460
- PAR ID:
- 10498895
- Publisher / Repository:
- Elsevier
- Date Published:
- Journal Name:
- Acta Biomaterialia
- ISSN:
- 1742-7061
- Subject(s) / Keyword(s):
- collagen DNA aptamer mineralization bone
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1016/j.actbio.2024.03.018
