Ex vivo Tissue Model for Breast Cancer Metastasis. Keagan Collins, Laura Graefe , Chris Hubley , Jaymin Modi, Ian Roberts & Bethany Porter Biomedical Engineering, University of Delaware, Newark, DE. Overview. Concept Generation. Testing.
Keagan Collins, Laura Graefe, Chris Hubley, Jaymin Modi, Ian Roberts & Bethany Porter
Biomedical Engineering, University of Delaware, Newark, DE
Juvenile bovine femoral heads were analyzed (obtainable within 24 hours of slaughter). After excess tissue is detached, bone is rinsed with water and media to remove contaminants. Next,
Background and Significance
Metastatic breast cancer is Stage Four cancer that has spread to other parts of the body including the lungs, liver, bones or brain. The objective of the Nohe Laboratory at the University of Delaware is to develop a perfusion bioreactor that can be used to study development of human metastatic breast cancer ex vivo. The bioreactor would maintain cell viability within a femoral head for a certain period of time. Afterwards, cancer cells will be perfused into the bone and progression of metastasis will be monitored within the bioreactor from the onset, as opposed to the commonly models where metastasis has already developed.Currently, the design is being used with human samples.
the bone is examined for cannulation sites and perfused. Afterwards, as stated by the Nohe Lab, media pumped through existing vasculature at rate of 8mL/hour for 10 days and replaced every 36 hours. Chamber placed on the vibration table (60 Hz) for 10 minutes every 24 hours
Figure 5: Femoral Head Artery Cannulation
Figure 2: Concepts
 Direct Stress
 Vibration Stress
 Vibration and Elevation
 Final Concept
Bone Viability Testing
Develop a perfusion bioreactor that maintains cell viability within a femoral head. Once a viable state has been achieved, cancer cells can be introduced and bone metastasis can be studied.
Direct force as a form of mechanical stress was rejecteddue to effects on cannulation, leading to the vibration method. In the third concept, the bone is elevated, away from the vibration platform. It was decided that although this design allows for optimal exposure to media, the elevation could dampen the vibrational effects. Thus the second concept was chosen and refined.
In the next ten years, the expectation is that the market for single use bioreactors will increase significantly. An example of a perfusion bioreactor is shown in Figure 1.The bioreactor for this project will house a femoral head, perfused with metastatic breast cancer. Most of the current literature focuses on the
cancer specifically, and not its effects on the bone, mainly because bone damage is usually only found after the cancer has been eradicated from the breast. There is treatment for metastatic breast cancer, however the success rate is not promising
Figure 6: Microscopy of cell waste products,
- For each 36 hour period, the juvenile femoral head
was using a minimum of 4300 mg of glucose.
- Glucose use was consistent over 10 days, proving
bone cell viability has not changed significantly.
- No visible media contamination (bacterial or other)
Figure 1: Perfusion Bioreactor
Figure 7: pH and glucose testing
- Recording of pH was taken every 36 hours during
the 10 day trial, with a reading taken immediately
before and after every media change.
- Regular pH drop of 1.0-1.5 (cells using nutrients).
Figure 3: final 2-D and 3-D schematics followed by prototype
The media, which was DMEM, served as both the reservoir and perfusion liquid. Replaced daily to ensure necessary nutrients and waste removal, DMEM (common culturing media) is pumped from chamber into the bone via cannulated points. Needles secure perfusion tubing from pump to artery.
Thanks to Dr. AnjaNohe, Jeremy Bonor and HemanthAkkiraju of the University of Delaware Department of Biological Sciences for their support and funding for the project. Additionally, we would like to thank Dr. Liyun Wang for advising the project, and Dr. Jenni Buckley and Dr. Robert Sikes for additional aid. Herman’s delicatessen provided the femoral head samples that were used for this project. Lastly, we would like to acknowledge University of Delaware’s Biomedical Engineering Department,
Figure 4: cannulation technique