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.

Introducing the Conductive Tissue Kit - It's Electric!


Our bodies contain a highway of integrated electrical communication called the nervous system. It helps regulate our movements, emotions, and even thoughts by having electricity chemically run across conductive tissue. That is why conductivity is a key ingredient to include when thinking about engineering tissues.

Today, we announced the availability of Dimension Inx LLC’s advanced material – 3D Graphene 3D-Paint. This novel material will provide users the ability to integrate conductivity into electroactive tissues, such as heart, muscle, and nerve in the lab. Research grade 3D Graphene, previously featured in and on the cover of the journal  ACS Nano, is now further accessible through our easy to use Conductive Tissue Kit.

One of the most challenging aspects for tissue engineers today is to be able to introduce electrical conductivity, an important and increasingly recognized biomaterial characteristic, into tissue systems. This is particularly useful for electroactive tissues such as skeletal and cardiac muscle, as well as peripheral and central nerve, which greatly benefit from electrical stimulus and/or grow based in part on the electrical conductivity of the material in their immediate vicinity.

With the Conductive Tissue Kit, researchers can begin to further explore the electroactive response of a variety of cells, tissues, and organs - leveraging the electrical conductivity of the 3D-Graphene to not only study basic biology, but to create tissue engineering and bioelectronic constructs. As-printed, 3D-Graphene is composed of approximately 60 vol.% graphene and 40 vol.% high quality PLGA polymer. Unlike other 3D-printable graphene composities on the market, 3D-Graphene is more graphene than polymer. Despite being mostly graphene, 3D-printed 3D-Graphene is flexible and has thus far exhibited excellent in vitro and in vivo results in academic studies.

There is no other material in the industry today that meets the needs that 3D-Graphene came to meet. While it is conductive, it also is cytocompatibile and integrates very nicely with living tissue, making it a versatile material useful for cardiac, nervous and skeletal muscle tissue, as well as circuits that could be implanted in the future. The kit brings all the components necessary to print and test the material.

Allevi continues to set the standard and provide the necessary foundational components for the tissue engineering and biofabrication industry. There is no question electrical conductivity is one of them. We are happy to continue to provide Dimension Inx's new 3D-Paints and advanced biomaterials to make well on our promise to the industry.”

Nearly all tissues operate via electrical signaling to some degree; but the biggest one, in addition to both peripheral and central nerves, is muscle (including cardiac muscle). Electrical conductivity as a biomaterial property is highly desirable and necessary in tissue engineering…. The problem is that traditional electrically conductive materials, like metals, do not integrate well with soft tissues in the body. 3D-Graphene is different.

Scientists Create Beating Heart Tissue in a Lab Dish

Check out the amazing work that our collaborators, Dr. Kevin Costa and his lab, are doing at Mount Sinai!


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.