Lucy Luo and IBBME UofT

February 20, 2020 @ 12:30 pm – 1:00 pm
Red Seminar Room
Donnelly Building

Event Name: Graduate Seminar Series: Cell and Tissue Stream

Graduate Seminar Series for the Institute of Biomaterials and Biomedical Engineering (IBBME). This day is for cell and tissue stream presenters.

Location: Red Seminar Room – Donnelly Building

Presentation Title: Biomimetic Mineralized Collagen Scaffolds and Their Effect on Osteogenesis
Osteoblasts derived from mesenchymal stromal cells (MSCs) form new bone during bone healing. Osteoblastic differentiation from MSCs (osteoinduction), is biased by the components and mechanics of the extracellular matrix (ECM). A key feature of bone ECM is the alignment of mineral with collagen fibrils. Since previous studies did not focus on adjusting mineral alignment, this project aims to assess the effect of varying degrees of mineral alignment on osteoinduction in MSCs in vitro. Scaffolds with aligned mineral are expected to induce greater expression of mature osteoblast markers in MSCs compared to scaffolds with mis-aligned mineral.
EDC (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide)-fixed collagen scaffolds were mineralized for 2, 3, 4, and 6 days using a validated process that permits biomimetic mineralization seen in native bone. Scanning electron microscopy (SEM) was used to assess mineral alignment and location. Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) quantified mineral alignment. To compare osteoinduction by scaffolds with varying degrees of alignment, qRT-PCR and immunofluorescent staining will be used to quantify gene and protein expression of early (e.g. type I collagen) vs. late osteoblastic markers (e.g. osteocalcin).
With SEM, 6 days of mineralization resulted in less aligned surface mineral compared to 2 days. SAED results quantitatively support the lack of alignment seen with SEM. Therefore, mineral alignment decreases as mineralization time increases. This tunable system will allow for comparison of osteoinduction between scaffolds with different degrees of mineral alignment. These results are expected to enhance the osteoinductivity of scaffolds as alternatives to autografts to treat non-union fractures.
Supervisor Name: Dr. Eli Sone, Dr. Sowmya Viswanathan
Year of Study: 2
Program of Study: MASc

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