Ian Bolland, editor of MPN’s sister title Med-Tech Innovation, spoke to Dr Sam Pashneh-Tala, a research fellow at the University of Sheffield.
Dr Pashneh-Tala is researching the fabrication of blood vessels in unique geometries for use in surgery, developing new medical devices, or studying conditions like cardiovascular disease. Dr. Pashneh-Tala has used Formlabs printers to design and create the blood vessel mould from the custom Biodegradable Polymer Emulsion he and his team developed.
What led you to undertake this research?
Cardiovascular disease is the number one cause of death worldwide and therefore there is a great need for replacement blood vessels. Tremendous advances have been made towards producing tissue-engineered blood vessels, but researchers have largely only been able to construct simple straight tubes. This is where my research fits in. I use Formlabs 3D printers to enable the production of tissue-engineered blood vessels with a variety of geometries that can recreate the bends, tapers and branches of the vascular network. My vision is to enable patient-specific vascular graft designs, tailored to each individual to provide improved surgical options.
How can your research help medical device manufacturers?
Currently, during the development of new vascular medical devices, manufacturers use synthetic blood vessel substitutes followed by testing on animals. My vessels offer a new testing platform to be used prior to animal testing, that could provide some of the mechanical and biological performance of native blood vessels.
The versatility of my tissue-engineered blood vessel technology also offers new opportunities to assist vascular surgeons. At present, surgeons most commonly utilise blood vessels harvested from elsewhere on a patient for vascular grafting (autografts). My technology permits the design of tissue-engineered vascular grafts with shapes that may assist surgeons in the grafting process. These graft designs may allow procedures to be less complicated or quicker and could also improve graft performance by better controlling the dynamics of the blood flow through the graft.
Which materials were used to create the blood vessel mould?
I began by using silicone to produce the moulds that defined the shapes of the tissue-engineered blood vessels. I used Formlabs technology to 3D print negative moulds from their Grey resin that were then cast with silicone to produce the silicone moulds. The silicone moulds were then assembled and cast or injected with the biodegradable, photocurable polymer material that forms the scaffold on which the tissue-engineered blood vessels are grown. After UV light exposure, to chemically crosslink the polymer, the scaffold is removed from the moulds, washed, sterilised, seeded with cells and then cultured in a bioreactor (also manufactured using my Formlabs 3D printer using their biocompatible and autoclavable Dental SG resin) to produce a tissue-engineered blood vessel. More recently, I have been exploring the use of Formlabs Elastic resin to directly manufacture the moulds I require.
Why did you choose Formlabs technology?
My research requires rapid design iterations and the fabrication of new components. Formlabs technology allows me to print components in my lab in a matter of hours, saving costs and development time.
The access to desktop manufacturing that Formlabs technology permits also empowers international collaborations. As part of my research, I work with Aptus Bioreactors, based in South Carolina, to develop some of my bioreactor technology. Although Aptus and I are on separate continents, we both use the Formlabs Form 2 platform and are able to share designs digitally and manufacture quickly at our perspective sites, allowing for rapid design progression.
What does the future hold for your research?
My research developing tissue-engineered blood vessels is ongoing with various new projects underway or in planning. Over the last year I have widened my scope by beginning the development of a tissue-engineered vein valve as a potential curative solution for deep venous insufficiency. This project has been enabled by my ability to produce a diverse range of vascular tissue shapes. I also have a project in development that will provide the foundations for automating the design and manufacture of bespoke, patient-matched, tissue-engineered vascular grafts by combining medical image processing and 3D printing. Finally, I am engaged in the early stages of using my technology to grow the world’s first novel human organ, a tubular heart.