sigma xi - a living band-aid
DESCRIPTION
Thermally Reversible Gels for Tissue EngineeringTRANSCRIPT
![Page 1: Sigma Xi - A Living Band-Aid](https://reader033.vdocument.in/reader033/viewer/2022052508/559627741a28aba05a8b4685/html5/thumbnails/1.jpg)
March 8, 2013 Sigma Xi Competition
Hydrogel Composites with Carbon Nanobrushes for Tissue
Engineering
William H. Marks & Carolina I. Ragolta
Additional AuthorsSze C. Yang, George W. Dombi, & Sujata K. Bhatia
![Page 2: Sigma Xi - A Living Band-Aid](https://reader033.vdocument.in/reader033/viewer/2022052508/559627741a28aba05a8b4685/html5/thumbnails/2.jpg)
Medical Need: Cardiac Regeneration✤ Coronary Artery Disease
is a leading killer of men and women worldwide
✤ Congestive heart failure has 1-year mortality rate of 40%
✤ Image Source: National Heart Lung and Blood Institute
![Page 3: Sigma Xi - A Living Band-Aid](https://reader033.vdocument.in/reader033/viewer/2022052508/559627741a28aba05a8b4685/html5/thumbnails/3.jpg)
Medical Need: Cardiac Regeneration✤ Myocardial infarction
can lead to death of 109 cardiomyocytes
✤ 1.5 million Americans suffer myocardial infarctions each year
✤ Image Source: Medicine.net
![Page 4: Sigma Xi - A Living Band-Aid](https://reader033.vdocument.in/reader033/viewer/2022052508/559627741a28aba05a8b4685/html5/thumbnails/4.jpg)
Abstract
✤ Study carbon nanobrushes (CNBs) embedded in hydrogels for scaffolding in tissue engineering
✤ CNBs provide internal structure, conductivity, and are non-toxic
✤ Tested the ability of fibroblasts and myocytes to adhere to the gel and mechanical properties
✤ CNBs alter mechanical properties providing a high degree of customization
✤ Gels show promise for many wound healing applications
![Page 5: Sigma Xi - A Living Band-Aid](https://reader033.vdocument.in/reader033/viewer/2022052508/559627741a28aba05a8b4685/html5/thumbnails/5.jpg)
Medical Need: Regenerative Medicine
✤ Biomaterials must be biocompatible, non-cytotoxic, non-hemolytic, and non-inflammatory
✤ They must degrade within the physiologic environment
✤ Must be easily prepared, implantable, and scalable✤ Must be clinically relevant
![Page 6: Sigma Xi - A Living Band-Aid](https://reader033.vdocument.in/reader033/viewer/2022052508/559627741a28aba05a8b4685/html5/thumbnails/6.jpg)
Prior Related Work
✤ Cell encapsulation for 3D tissue growth (Hunt et al., 2010)✤ Collagen matrices for fibrogenesis (Chen et al., 2009)✤ Alginate gels with carbon nanotubes provide mild
inflammatory response (Kawaguchi et al., 2006)✤ “Scar in a Jar” collagen matrix for flexor tendon healing
(Dombi et al., 1994)✤ Cartilage tissue engineering by accurately spinning
hydrogels (Coburn et al., 2011)
![Page 7: Sigma Xi - A Living Band-Aid](https://reader033.vdocument.in/reader033/viewer/2022052508/559627741a28aba05a8b4685/html5/thumbnails/7.jpg)
Clinically Relevant Cell Lines
Primary Cardiac FibroblastsSource: Dr. Andrew Pelling, UCL
Primary Cardiac MyocytesSource: Dr. Poling Kuo, Harvard
![Page 8: Sigma Xi - A Living Band-Aid](https://reader033.vdocument.in/reader033/viewer/2022052508/559627741a28aba05a8b4685/html5/thumbnails/8.jpg)
Carbon Nanobrushes
✤ Electrically conducting polymers grafted onto carbon nanotubes
✤ Conductivity of materials is about 0.1 S/cm
✤ 5-20µm in length✤ 13-30nm in diameter✤ Imaged by negatively
staining with phosphotungstate
![Page 9: Sigma Xi - A Living Band-Aid](https://reader033.vdocument.in/reader033/viewer/2022052508/559627741a28aba05a8b4685/html5/thumbnails/9.jpg)
Pluronic F-127 Poloxamer Hydrogels✤ Reverse phase-change properties: solid at 37 , liquid at ℃
room temperature✤ Triblock copolymer of PEO-PPO✤ Non-ionic and biocompatible
![Page 10: Sigma Xi - A Living Band-Aid](https://reader033.vdocument.in/reader033/viewer/2022052508/559627741a28aba05a8b4685/html5/thumbnails/10.jpg)
Preparation of Composite Hydrogels with Carbon Nanobrushes✤ 30wt% poloxamer solution✤ Various CNB
concentrations✤ 0vol%✤ 0.1vol%✤ 0.5vol%✤ 1vol%
✤ Solidified at 37 and then ℃seeded with cells and DMEM
![Page 11: Sigma Xi - A Living Band-Aid](https://reader033.vdocument.in/reader033/viewer/2022052508/559627741a28aba05a8b4685/html5/thumbnails/11.jpg)
Growth of Fibroblasts
Fibroblasts in top layer of poloxamer gel after 48 hours
![Page 12: Sigma Xi - A Living Band-Aid](https://reader033.vdocument.in/reader033/viewer/2022052508/559627741a28aba05a8b4685/html5/thumbnails/12.jpg)
Migration of Fibroblasts
Fibroblasts in middle layer of poloxamer gel after 48 hours
Fibroblasts in bottom layer of poloxamer gel after 48 hours
![Page 13: Sigma Xi - A Living Band-Aid](https://reader033.vdocument.in/reader033/viewer/2022052508/559627741a28aba05a8b4685/html5/thumbnails/13.jpg)
Growth of Myocytes
Myocytes in top layer of poloxamer gel after 48 hours
![Page 14: Sigma Xi - A Living Band-Aid](https://reader033.vdocument.in/reader033/viewer/2022052508/559627741a28aba05a8b4685/html5/thumbnails/14.jpg)
Rheology: Temperature Sweep
Temperature sweep test of gels containing 0vol% and 5vol% CNB
![Page 15: Sigma Xi - A Living Band-Aid](https://reader033.vdocument.in/reader033/viewer/2022052508/559627741a28aba05a8b4685/html5/thumbnails/15.jpg)
Rheology: Time Sweep
Time sweep test of gels containing 0vol% and 5vol% CNB at 37℃
![Page 16: Sigma Xi - A Living Band-Aid](https://reader033.vdocument.in/reader033/viewer/2022052508/559627741a28aba05a8b4685/html5/thumbnails/16.jpg)
Rheology: Frequency Sweep
Frequency sweep test of gels containing 0vol% and 5vol% CNB at 37 ℃showing a crossover from predominately elastic to predominately viscous
![Page 17: Sigma Xi - A Living Band-Aid](https://reader033.vdocument.in/reader033/viewer/2022052508/559627741a28aba05a8b4685/html5/thumbnails/17.jpg)
Discussion
✤ Hydrogels embedded with CNBs support cell growth and migration
✤ CNBs change the properties of the gel on a macro scale by altering the frequency of the sol-gel transition point✤ Gels transition from predominately elastic to
predominately viscous✤ Additional degree of customizability
![Page 18: Sigma Xi - A Living Band-Aid](https://reader033.vdocument.in/reader033/viewer/2022052508/559627741a28aba05a8b4685/html5/thumbnails/18.jpg)
Ongoing and Future Work
✤ Properties of gels with different wt% of poloxamer✤ Incorporating crosslinkers into hydrogels✤ Injectability✤ Experiments with additional cell lineages
![Page 19: Sigma Xi - A Living Band-Aid](https://reader033.vdocument.in/reader033/viewer/2022052508/559627741a28aba05a8b4685/html5/thumbnails/19.jpg)
Translational Potential
Tissue PatchesSource: Gore
Skin GraftsSource: Medline
Tissue ScaffoldSource: National
Institute of Standards and Technology
![Page 20: Sigma Xi - A Living Band-Aid](https://reader033.vdocument.in/reader033/viewer/2022052508/559627741a28aba05a8b4685/html5/thumbnails/20.jpg)
Acknowledgements
✤ Dr. Sujata K. Bhatia, SEAS, Harvard
✤ Dr. Sze C. Yang, University of Rhode Island
✤ Dr. George W. Dombi, University of Rhode Island
✤ Dr. Patrick Campbell, SEAS, Harvard (Disease Biophysics Group)
✤ Harvard School of Engineering and Applied Sciences