3D Bioprinting Replacement Heart Valves

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Throwing it back today to show you this heart valve that was 3d bioprinted using the Allevi 2 with collagen from Advanced BioMatrix.

Your heart has four valves (one for each chamber) that are made up of thin flaps of tissue called cusps. These flaps open and close to allow blood to move through the heart while beating.  The cusps attach to an outer ring of tougher tissue called the annulus. The annulus helps the valve maintain proper shape under the normal strains and stresses of a heartbeat. 


It is essential that your valves open and close tightly to ensure proper blood flow through the heart and onto the rest of your body. A diseased or damaged valve can give you an irregular heartbeat and eventually lead to heart failure. More than 5 million Americans are diagnosed with heart valve disease every year.

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Many people can live with valve disease and do not require surgery. However, in some cases, the valve needs to be fixed or replaced. Current methods for replacing a damaged valve included plastic parts or animal tissues.

Allevi users are working towards a future where your #doctor is able to 3d bioprint a custom replacement valve from your own heart cells to reduce the rate of failure and rejection. 3D bioprinting is an amazing design tool that allows you to print custom geometries and tune the rheological properties to provide your cells with the support structure they need to do their job. Just another amazing way our users are changing the future of medicine. #buildwithlife #healwithlife

Allevi Author - Valentine's Day Edition: GWU Bioprints Heart Tissue

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George Washington University joins the #AlleviAuthor club with their new paper titled, “Use of GelMA for 3D printing of cardiac myocytes and fibroblasts” and published in Journal of 3D Printing in Medicine.

First let’s review some basics about your heart! Heart tissue is composed of two main cell types; cardiac fibroblasts (CFB) & cardiomyocytes (CMC).


Cardiomyocytes are the contracting cells which allow the heart to pump. Each cardiomyocyte needs to contract in coordination with its neighboring cells to efficiently pump blood from the heart, and if this coordination breaks down then the heart may not pump at all.

Fibroblast cells give support to the muscle tissue. They are unable to provide forceful contractions like cardiomyocytes, but instead are largely responsible for creating and maintaining the extracellular matrix which forms the mortar in which cardiomyocyte bricks are embedded. Fibroblasts also play a crucial role in responding to injury by creating collagen while gently contracting to pull the edges of the injured area together.

In previous academic studies, tests of pure populations of cardiomyoctes have failed to stay viable making it difficult to study the heart in a lab setting. In their recent paper, the team at George Washington University set out to determine how 3D bioprinting affects these two types of cells and if there is a way to create viable 3D tissue in the lab by bioprinting both CMCs and CFBs in tandem.

The team studied the effects of temperature, pressure, bioink composition, and UV exposure to determine the best conditions for 3D bioprinting heart muscle.

Through LIVE/DEAD assays, bioluminescence imaging and morphological assessment, they determined that cell survival within a 3D bioprinted CMC-laden GelMA construct was MORE sensitive to extruder pressure and bioink composition than the fibroblast-laden constructs. Also they determined that BOTH cell types were adversely impacted by the UV curing step. And finally they determined that using a mixture of cardiomyocytess and cardiac fibroblasts increased viability of the tissue- showing that CMCs <3 CFBs.

Cheers to the team at GWU! Their research creates an important foundation for future studies of 3D bioprinted heart tissue.

Read their paper here.

Research Spotlight: Dr. Doris Taylor is Building a Heart from Scratch

Here at Allevi, we’re always keeping an eye out for research being done in tissue engineering and stem cell biology. Together, these disciplines form the backbone of regenerative medicine.

So, it’s only natural that Dr. Doris Taylor’s research at the University of Minnesota and at the Texas Heart Institute caught our eye. Click the image below to check out this brief video describing the premise of her work:

In sum, her approach to creating tissues and organs for transplantation is this: first, wash out the existing cells in a donor’s organ (using a standard detergent called sodium dodecyl sulfate, or SDS) to leave only the extracellular matrix, and then re-cellularize this natural scaffold with the patient’s stem cells. After cell growth and proliferation, the end result is a brand new heart made from the recipient’s own cells. This approach is groundbreaking because it lessens, or nullifies altogether, the problems associated with donor organ rejection.

How could Allevi help out with this goal? Well, we know that an extracellular matrix scaffold is needed to seed the patient’s cells and eventually grow a heart. Why not 3D bioprint such a scaffold, instead of obtaining it by washing out the cells of a animal, or donor’s heart?

Imagine: a patient suffers cardiac trauma and is in need of new heart tissue, or a new heart entirely. A 3D bioprinter could print an extracellular matrix scaffold customized for the patient, and then the patient’s cardiac stem cells would be grown on the matrix. Given the proper incubation, environment, and growth factors, a new, healthy, beating heart could be ready for the patient in a matter of days. This takes the need for a donor out of the transplant equation.

Allevi is looking forward to what Dr. Taylor and her team come up with next. The technique she has developed could be applied to a wide array of organs, and even blood vasculature. The possibilities are endless, and a 3D bioprinter can only help realize the promise of regenerative medicine.

Click here for more information about Dr. Doris Taylor and her work.

Bioprinting for Cardiac Cell & Tissue Engineering Applications

As one of the first groups who are working with Allevi to assess the seemingly endless potential of their bioprinter, we felt it would be good to share a bit about why we’re excited about bioprinting. Sohaib and his team have done a fantastic job describing the potential advances that bioprinting brings to tissue engineering, and we are one of the groups seeking to benefit from it. Our group (the Costa Laboratory at Mount Sinai in New York City) is primarily interested in the heart and how its cells (cardiomyocytes, cardiac fibroblasts, vascular cells, etc.) behave in and respond to different 3D environments; the end goal of our work is to understand and develop new treatments for diseases that affect contractile performance of the heart. The Allevi bioprinter, once perfected, is expected to give us new ways to examine various experimental and/or therapeutic conditions with improved throughput and biofidelity, ultimately increasing our productivity and advancing our understanding of the human heart.

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In the mean time, we will be contributing to the product development by assessing cell viability and function in the Allevi system. We want to see if cardiomyocytes, cardiac fibroblasts, stem cells, and a number of other human and animal cells types of interest will survive and thrive within the 3D environment of Allevi's unique printable materials. In the early stages, we will simply be putting our cells in the Allevi system, printing them into culture wells, photocuring, and assessing short- and long-term cell viability, as well as key microstructural and molecular analyses. This will most likely involve some iterative troubleshooting, but once we have worked with Allevi to optimize the system for our cells, we will progress to integrating the bioprinter’s ability to create more sophisticated 3-D cardiac tissue constructs. The possibilities seem almost endless; once we have a better idea of what the printer is capable of producing, we will update the community with a revised project plan.