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In JoVE (1)
Other Publications (2)
Articles by Lindsay E. Fitzpatrick in JoVE
JoVE Bioengineering
Fabrication of Micro-tissues using Modules of Collagen Gel Containing Cells
1Institute of Biomaterials and Biomedical Engineering / Department of Chemical Engineering and Applied Chemistry, University of Toronto, 2Institute of Biomaterials and Biomedical Engineering, University of Toronto
Creation of micro-tissues using cylindrical collagen gels, called modules, that contain embedded cells and which surface is coated with endothelial cells.
Other articles by Lindsay E. Fitzpatrick on PubMed
PNIPAAm-grafted-collagen As an Injectable, in Situ Gelling, Bioactive Cell Delivery Scaffold
We synthesized two thermoresponsive, bioactive cell scaffolds by decorating the backbone of type I bovine collagen with linear chains of poly(N-isopropylacrylamide) (PNIPAAm), with the ultimate aim of providing facile delivery via injection and support of retinal pigment epithelial (RPE) cells into the back of the eye for the treatment of retinal degenerative diseases. Both scaffolds displayed rapid, subphysiological phase transition temperatures and were capable of noninvasively delivering a liquid suspension of cells that gels in situ forming a cell-loaded scaffold, theoretically isolating treatment to the injection site. RPE cells demonstrated excellent viability when cultured with the scaffolds, and expulsion of cells arising from temperature-induced PNIPAAm chain collapse was overcome by incorporating a room-temperature incubation period prior to scaffold phase transition. These results indicate the potential of using PNIPAAm-grafted-collagen as a vehicle for the delivery of therapeutic cells to the subretinal space.
On the Mechanism of Poly(methacrylic Acid -co- Methyl Methacrylate)-induced Angiogenesis: Gene Expression Analysis of DTHP-1 Cells
Identifying the critical molecules associated with "biocompatibility" is a grand challenge. Poly(methacrylic acid -co- methyl methacrylate) (MAA) beads improve wound closure and wound vascularity in vivo, but the mechanism of this phenomenon is unknown. We used quantitative real-time PCR to identify the subtle changes in the expression of a small selection of molecules involved in wound healing and angiogenesis in a macrophage-like cell (dTHP-1) treated with the MAA beads (45 mol% methacrylic acid). MAA beads decreased the expression of osteopontin (OPN) compared to poly(methyl methacrylate) (PMMA) and untreated cells, and increased the expression of IL-1β, IL-6 and TNF-α over the 24-96 h of the experiment. Interestingly, molecules associated with angiogenesis, such as bFGF, CXCL12, HIF-1α, PDGF-B, TGF-β and VEGF, were not significantly affected by MAA beads over the course of the study. MAA beads also increased the gene expression of OPN in HUVEC compared to untreated cells, while PMMA beads did not. MAA beads modified the phenotype (gene expression) of dTHP-1 cells in a subtle yet distinct manner that was different than PMMA. It remains to connect the changes in OPN in dTHP-1 (and HUVEC) and other molecules to the enhanced vascularity seen in vivo with this polymer.
