Regenerating cartilage damage by using biological scaffolds of cellulose and soy

The EHU’s BIOMAT group has developed a biodegradable gel using natural materials and shape memory for use in tissue engineering

A team in the Department of Chemical and Environmental Engineering at the EHU-University of the Basque Country and which is part of the BIOMAT group has developed structures for cartilage regeneration based on cellulose, gelatin and soy proteins with promising mechanical and biological properties. Obtained from food industry by-products, these scaffolds stand out because of their biocompatibility, printability and potential to promote cell viability in tissue engineering applications.

Imagine being able to repair a meniscus injury by printing, in situ, a three-dimensional structure that fits like a glove, so that it not only performs the function of a scaffold enabling cells to become adhered and reproduce, but can also act as a source of nutrients for them, before eventually biodegrading and disappearing, thereby repairing the damaged cartilage. “The aim is to be able to use natural materials, and thus move away from metal or plastic prostheses,” explained Iraia Osquila, a researcher at the EHU’s Faculty of Engineering-Gipuzkoa. Driving forward personalised biomedicine requires tissue engineering to find biocompatible materials with characteristics that provide them with excellent printability and mechanical integrity.

Iraia Osquila, an EHU researcher, has developed —under the supervision of Dr Pedro Guerrero and Professor Koro de la Caba— a bio-ink made from cellulose, gelatin and soy protein, and which uses a more environmentally friendly and sustainable solvent that dissolves the cellulose effectively and is non-toxic to cells. “By using natural, biodegradable and biocompatible materials, we have managed to create a gel which, when 3D-printed, is suitable for biomedical applications in cartilage regeneration,” explained the lecturer Guerrero.

The research team in the BIOMAT group saw that “the printed scaffolds guide the formation of new tissue and act as substrates to promote cell adhesion, without hindering their proliferation; they behave like an artificial extracellular matrix in which cells organise themselves into three-dimensional structures, mimicking the structure of native tissue”, explained Osquila.

Shape memory

The BIOMAT research group’s work focuses, among other things, on the design of materials based on proteins and polysaccharides (cellulose, agar, etc.) using sustainable products and processes, and on the study of their mechanical properties. In this case, the team carried out an exhaustive study of the mechanical properties, biocompatibility and toxicity of the aforementioned 3D-printed scaffolds.

Tensile and compression tests indicate that “the structure has shape memory; in other words, when a particular force is no longer applied, the material returns to its original shape”, they said. This feature is crucial because “cartilage is also subjected to compression or tensile forces that cause it to deform, but it then recovers its original shape when these forces are removed”, added Osquila.

The team saw that “cellulose reinforces the structure and provides rigidity and tensile strength. The more cellulose the structure contains, the greater the strength”. Soy protein, meanwhile, “gives the ink body so it can be printed, and gelatin serves as nourishment for the cells”, added Guerrero. The effective interactions among all the ink’s components offer properties that improve the mechanical performance and biocompatibility of the scaffolds. “We managed to dissolve the cellulose inside the ink, and in doing so we obtained the properties we needed to be able to print the structures with precision and promote cell growth and tissue regeneration,” he confirmed.

Guerrero also emphasised that the raw material for this bio-ink is of natural origin: “We’re talking about proteins and cellulose originating from food industry waste. Our work demonstrates that by using natural materials we are also able to achieve excellent solutions: highly consistent materials that serve as reinforcement and possess excellent mechanical properties.” The team’s aim is to develop materials that mimic natural ones. “By means of minor natural modifications, we obtained biocompatible materials that do not harm the body, thus helping us move towards achieving more sustainable and personalised medicine,” he stressed. In this respect, the BIOMAT group develops and studies a range of materials in the laboratory.

Additional information

This work is part of the PhD thesis that Iraia Osquila-Pérez de Azpeitia is writing up at the Faculty of Engineering-Gipuzkoa under the supervision of Koro de la Caba, Professor of the Department of Chemical and Environmental Engineering, and Dr Pedro Guerrero, both of whom are researchers in the BIOMAT Group.