Home Academic information A breakthrough in tissue engineering because “shape memory” supports tissue growth

A breakthrough in tissue engineering because “shape memory” supports tissue growth

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Bioabsorbable tissue scaffolds

Research published today has demonstrated the viability of 3D printed tissue scaffolds that degrade safely while promoting tissue regeneration after implantation.

The scaffolds have shown very promising tissue healing performance, including the ability to support cell migration, “internal growth” of tissues and revascularization (growth of blood vessels).

Professor Andrew Dove, School of Chemistry, University of Birmingham, led the research group and is the lead author of the paper published in Nature Communications, which characterizes the physical properties of scaffolds and explains how their “Shape memory” is the key to promoting tissue regeneration.

Professor Dove commented: “Scaffolds have evenly distributed and interconnected pores that allow the diffusion of nutrients from surrounding tissues. Shape memory means that this structure is maintained when the scaffold is implanted into the tissues, which promotes infiltration of cells into the scaffold while encouraging tissue regeneration and revascularization.

The scaffolds were created using 3D printing resin ‘inks’ developed during a major biomaterials research program led by Professor Andrew Dove of the University of Birmingham and the University. from Warwick. The resins are marketed under the trade name 4Degra ™ by 4D Biomaterials, a spin-off company of the University of Birmingham Enterprise and Warwick Innovations which was launched in May 2020.

Scaffolds have shown several major advantages over current approaches used to fill soft tissue voids that remain after trauma or surgery, including sufficient elasticity to conform to irregular spaces, the ability to undergo compression up to to 85% before returning to their original geometry, compatibility with fabrics and non-toxic biodegradation.

The article describes several compositions for 4Degra ™ resins that allow materials of a wide range of strengths to be manufactured. All compositions include a photoinitiator and a photoinhibitor to ensure that the resins quickly turn into gel upon exposure to light in the visible spectrum to allow their 3D printing in a range of scaffold geometries.

The researchers showed that the materials were not toxic to the cells and they also performed mechanical tests to ensure that the scaffolds could regain their shape, geometry and pore size after compression, and performed tests who have shown that scaffolds can fill an irregularly shaped void in an alginate gel that has been used to mimic soft tissue.

Laboratory studies have shown that the scaffold degrades by surface erosion to non-acidic products, which means that the scaffold structure allows for slow and continuous tissue infiltration.

The results were confirmed in a mouse model that simulates implantation into adipose (fatty) tissue. These studies showed adipocyte and fibroblast infiltration and vascularity at two months, as well as tissue disposition and the presence of macrophages indicating normal tissue restoration rather than damaged scar tissue or an inflammatory response.

At four months, the researchers found small mature blood vessels in the surrounding tissue. The scaffolds have also demonstrated excellent biocompatibility. The collagen capsule formed around the implants was less than 200 µm thick, which is well below the 500 µm threshold used for biocompatibility in other studies, and there was no calcification or necrosis.

Also at four months, 80% of the scaffold was still present, demonstrating the slow degradation predicted by laboratory studies and indicating that the scaffolds would provide support for over a year, leaving sufficient time for mature tissue to grow. . Controls, who used poly (L-lactic) acid (PLLA) as a comparator, did not show a significant reduction over the four month period.

Professor Dove comments: “3D printed materials have received a lot of attention in the world of tissue engineering. However, void-filling materials provide mechanical support, biocompatibility, and surface erosion characteristics that ensure constant tissue support during the healing process, meaning that a fourth dimension (time) must be taken into account. account in material design.

“We have demonstrated that it is possible to produce highly porous shape memory scaffolds, and our processes and materials will enable the production of self-adjusting scaffolds that adopt the geometry of soft tissue voids in minimally invasive surgery without deform or apply pressure to surrounding tissue. . Over time, the scaffold erodes with minimal swelling, allowing slow continuous tissue infiltration without mechanical degradation.

4D Biomaterials has made rapid progress in increasing the production of 4Degra ™ resin-based inks at its laboratory in MediCity, Nottingham (UK) and now offers technical grade materials for commercial supply to companies. 3D printing and medical device manufacturers.

CEO Phil Smith said, “We are looking to collaborate with innovative companies in Europe and North America to develop a new generation of 3D printed medical devices that translate the unique advantages of the 4Degra ™ resin-ink platform into improved therapeutic outcomes for patients ”. With the first customer shipments shipped and a fundraising round about to close, Phil added, “We will be making more announcements shortly.

Notes to Editors:

  • For more media information, interviews or an embargoed copy of the article, contact Tony Moran, University of Birmingham or +44 (0) 7827 832312. Outside opening hours +44 (0) 7789 921 165. For more business or investment information, contact Philip Smith at 4D Biomaterials.
  • 4D Medicine Ltd (marketed as 4D Biomaterials) was founded by a team of world-class chemists and engineers to develop and market a new line of patent-pending printable resins that promise to transform patient outcomes in a range of biomedical applications.
  • The University of Birmingham Enterprise helps researchers turn their ideas into new services, products and businesses that meet real-world needs. We also support innovators and entrepreneurs with mentoring, advice and training and manage the academic advisory service of the University.
  • Warwick Innovations is the knowledge exchange and commercialization arm of the University of Warwick. It provides business expertise, intellectual property protection, support services and funding to the University’s academic innovators in all disciplines. It designs and delivers corporate training programs for researchers at all stages of their career development.
  • The University of Birmingham is ranked among the top 100 institutions in the world. His work brings people from all over the world to Birmingham, including researchers, teachers and over 6,500 international students from over 150 countries.


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