1 / 14

Microencapsulation of murine leydig tumor cells for cell transplantation

Microencapsulation of murine leydig tumor cells for cell transplantation. Albert Kwansa - Leader John Harrison - Communicator Yik Ning Wong - BSAC Eric Lee - BWIG Advisor: Professor William Murphy Client: Dr. Craig Atwood. Client Introduction. Dr. Craig Atwood, Geriatrics Research

alijah
Download Presentation

Microencapsulation of murine leydig tumor cells for cell transplantation

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Microencapsulation of murine leydig tumor cells for cell transplantation Albert Kwansa - Leader John Harrison - Communicator Yik Ning Wong - BSAC Eric Lee - BWIG Advisor: Professor William Murphy Client: Dr. Craig Atwood

  2. Client Introduction Dr. Craig Atwood, Geriatrics Research ~The Laboratory of Endocrinology, Aging and Disease (LEAD) • Project Motivation: Decrease in testosterone production by leydig cells can disrupt the HPG axis and lead to a variety of disorders.

  3. Background - HPG Axis Hypothalamus - - GnRH LH & FSH Testosterone + Anterior Pituitary - - Target Cells LH FSH Testosterone Inhibin + + Male Gonads Testosterone Leydig Cells Sertoli Cells

  4. Background - Hypogonadism • Primary & Secondary sources • Congenital defects • Acquired disorders • Natural occurrence with aging • Possible symptoms • Bone & muscle atrophy • Reduced mental acuity • Infertility

  5. Microencapsulation • Replace the streroidogenic function of leydig cells • Tiny particles are surrounded by a coating to give small capsules with many useful properties • Immuno-isolation against host response • Criteria for microencapsulation • Sufficient diffusion distance • Provide sustained release of hormone

  6. Parameters • Mesh size • Pore size of hydrogel • Allow diffusion of nutrients, gases, wastes, and hormones • Prevent large immune molecules (antibodies) and cells • Microcapsule diameter • Sufficient diffusion of gases (oxygen) and nutrients • Avoid cell necrosis and hypoxia • Degradation • Remain intact long enough to sustain a critical cell mass and provide adequate hormone release • Thickness • Affect diffusion rate

  7. O HO H n O O PEG PEGdA O O n Material Selection • Polyethylene glycol (PEG) • Synthetic polymer (pure) • Minimize protein adsorption  reduced fibroblast overgrowth • Allows for chemical modification to suit specific purposes • Difficult for cells to adhere

  8. Size exclusion via mesh size LH, FSH, O2, Nutrients Antibodies Testosterone, Wastes Encapsulated leydig cells Pore & Capsule Size • Immunoprotection and Hypoxia • Mesh size of 4-5nm • Human antibodies: 5.4nm (IgG) • FSH(2.2nm), LH(3nm) • Capsule size of 100µm • Rule of thumb • PEGdA (MW 12000)

  9. Past work- Assays • Diffusion into/out-of PEGdA network (BSA-Fluorescein) • Observed diffusion • Cell viability (LIVE/DEAD assay [qualitative]) • Cells viable up to 8 days • Florescence strongly concentrated at the edges of hydrogels • Hypoxia? Immune response? Effect of UV? • Testosterone production (ELISA) • Inconclusive results • Cell anchorage? Effect of UV?

  10. Project Status • Current goal – Extend cell viability and increase testosterone production

  11. Experimental Design Teflon film (spacer) • Diffusion distance • UV exposure • Cell adhesion peptides (RGD) Coverslip hydrogel PEGdA Petri dish bottom

  12. Experimental Protocol

  13. Materials List

  14. Questions?

More Related