Fraunhofer IAP and NMI develop 3D printed biomimetic tissue substitute for medical implant applications
Multilayer material combines a printed metastructure with electrospun collagen passed biocompatibility testing, with a joint patent filed and industrial partners now being sought
Researchers at the Fraunhofer Institute for Applied Polymer Research (IAP) and the NMI Natural and Medical Sciences Institute have developed a multilayer biomimetic tissue substitute designed to replicate the mechanical and biological characteristics of natural human tissue.
The work, carried out under the PolyKARD project and funded by Germany’s Federal Ministry of Research, Technology and Space (BMFTR), built the material from three distinct layers: a dense polyurethane acrylate polymer film, a 3D printed wavy metastructure that governs the mechanical response of the composite and electrospun collagen produced using a process developed at the NMI.
Enzymatic and non-invasive spectroscopic analyses were used to perform quality control of the collagen fibers.
The aim of the configuration was to look into a common issue that affects implant material development – the reproduction of nonlinear stress and the strain behavior of soft biological tissues, which are initially compliant under low loads but which become substantially stiffer as strain increases.
“Our tensile tests show very similar strain and strength behavior to natural pericardial tissue. When stretched, the waves elongate, allowing the material to remain flexible. Only at higher strain does stiffness increase abruptly,” said Dr. Hadi Bakhshi, an expert in 3D printing technologies for medical applications at Fraunhofer IAP.
Dr. Bakhshi developed the material and printing technology alongside Dr. Wolfdietrich Meyer.
“By deliberately combining structural design and biomaterials, we can achieve mechanical properties that closely resemble those of natural tissues,” added Dr. Meyer.
Biocompatibility and patent filing
Cell-material interaction studies conducted at the NMI confirmed the material’s biocompatibility, and cytotoxicity testing showed no adverse cellular effects. Experiments with human skin fibroblasts and epithelial cells indicated that the three-dimensional fiber network morphology supported cell adhesion and growth.
“The results show that technical materials and biological functionality can be specifically engineered and combined into biomimetic materials,” said Dr. Hanna Hartmann from the NMI.
“This opens up new possibilities for the development of biohybrid implants. That is why we have now jointly filed a patent for this tissue substitute.”
The material concept has the potential to be transferable to multiple medical fields, including artificial blood vessels, stent grafts, dura mater substitutes, and artificial skin applications.
“Our development has reached a stage where it can be translated into concrete applications,” said Meyer. “The next step is to collaborate with industrial partners to realize specific products and bring them to market-ready applications.”
