Chitosan, a material made from renewable resources, appears promising for tissue regeneration. Researchers at Universidad de Antioquia are testing new methods to develop chitosan-gelatin scaffolds for cartilage regeneration.

Photo: chitosan particle

Factors such as age, accidents, intense physical activity and certain diseases can wear out articular cartilage, specially knee cartilage, causing acute pain, decreased movement, and even disability.   Since cartilage tissue does not regenerate quickly due to lack of blood supply, scientists are making efforts to find ways to kick-start tissue regeneration through the use of chemistry, biology and engineering.

A potential solution involves growing tissue in the lab so that it can be used to replace lost tissue segments. “This process involves the use of scaffolds that mimic the shape and function of natural scaffolding. The scaffold is filled with tissue cells so that they can grow and repopulate the target organ, thus forming functional tissue,” says UdeA researcher and bioengineer Ana Cañas-Gutierrez.

The scaffold material must be compatible with the body and must not contain substances which are toxic for the cells. Chitosan looks promising to replace natural materials that make up the matrix surrounding tissue cells, such as collagen and glycosaminoglycans, which cannot be synthesized in the laboratory.   

Chitosan, the wonder polymer

Chitosan is a material derived from chitin, a naturally occurring polysaccharide found in the shells of crustaceans such as shrimps, crabs and lobsters, as well as insects, which shares many similarities with other animal molecules. It is commonly used as a non-polluting pesticide, wound-healing agent, and in tissue engineering for tissue repair and regeneration.   

“Chitosan is a biocompatible material as it is very similar to other components of the extracellular matrix, which reduces the risk of being rejected by the cells. Moreover, chitosan is a biodegradable material, which means it is fully absorbed into the body without causing harmful effects. One of the advantages of chitosan is that it can be obtained from fish industry waste,” Cañas said.

Universidad de Antioquia has been actively engaged in projects aimed at taking advantage of chitosan versatility, which encouraged Ana Cañas to focus her Master’s research on how to get the most out of chitosan for specific tissue regeneration purposes.

Photo: the image shows cells growing through a chitosan-gelatin scaffold

Chitosan-gelatin composite

Throughout his MS degree, Cañas worked closely with researchers from the UdeA Material Science Research Group and the Genetics, Regeneration and Cancer Research Group, with whom she managed to carry out the physical-chemical characterization and in vitro testing of chitosan, under the supervision of Prof. Carmiña Gartner and Prof. Jean Paul Delgado.     

Cañas was able to develop chitosan-based scaffolds which she reinforced by adding pure gelatin, one of the world's most widely used edible substances.

“Gelatin is composed primarily of collagen, the protein that makes up the connective tissues, bones, and skin of animals, and also has properties that help improve cell adhesion,” she said.  The results showed that gelatin also improved the mechanical properties of chitosan making it more resistant to compressive force.   

The purpose of chitosan scaffolds is to mimic a porous structure similar to the three-dimensional network by which cells are attached to the body. After evaluating the chemical properties of chitosan as well as its resistance to compression and porosity, in vitro testing was performed.

When blended with gelatin, chitosan promotes an environment suitable for cells. Factors such as biodegradation, cytotoxicity, genotoxicity, and cell adhesion were evaluated and results look promising. Also, both materials were analyzed prior to the construction of the scaffolds to ensure they meet the requirements for use in tissue engineering.    

A test to evaluate the proliferation of keratinocytes (the predominant cell type in the epidermis) in chitosan-gelatin scaffolds was carried out in the laboratory. The results showed that the cells were able to proliferate and grow within the pores of the scaffolds.     

However, this development must first undergo in vivo trials in order to predict compatibility and determine whether chitosan is capable of maintaining its properties when introduced into the body.

Probably in a few years, this Colombian development will provide solutions to a wide range of knee problems and give people with knee cartilage injuries the opportunity to practice activities such as jogging or running.