By cross-linking aglinate with gelatin from fish, scientists have increased the mechanical strength of 3D printed tissue scaffolds to help people recover from injuries.
The new marine biomaterial will be used to create novel bioink that can be extruded from a 3D bioprinter in the shape of any desired tissue. 3D Bioprinting can help heal injuries by providing a complementary patch of material for transcription overtop of the damaged area. Experts believe it will be key to providing medical care for astronauts in outer space where supplies and expertise are limited.
Alginate is a salt of alginic acid derived from brown seaweed, whereas fish gelatin is a colorless protein extracted from the collagen of fish. It appears that marine derived biomaterials are particularly useful for increasing the durability of these surgical scaffolds, at least until the injury is completely healed.
“In this study, four different concentrations of alginate (1%, 2%, 3%, and 4%) and three low concentrations of f-GelMA (4%, 5%, and 6%) were investigated and found to form double networked alginate/f-GelMA hydrogels,” the researchers explain.
The authors call this material a marine-based interpenetrating polymer network where the alginate is cross-linked via chemical bonds and the gelatin takes the form of a more physical network.
“In the mechanical properties test, the pure alginate hydrogel showed a typical increase in mechanical strength with the increase of concentration and low mechanical strength when its compressive modulus was around 40 kPa, even at 4% alginate, compared with alginate/f-GelMA IPN hydrogel where the modulus of alginate/f-GelMA was approximately 40 kPa at 1% alginate.”
They also found that swelling decreased in proportion to the concentration of alginate.
“For the alginate/f-GelMA hydrogel, the mass swelling ratio for all tested groups was lower than for the pure alginate group,” the researchers continue. “This was due to the increased crosslinking density from the addition of f-GelMA which generated additional polymeric networks via covalent bonding…The swelling properties of hydrogel mainly depend on the hydrogel pore size, polymer concentration, density of cross-linking, and the interaction with solvents.”
Furthermore alginate/f-GelMA appears to exhibit a highly porous structure that allows for easier transportation of nutrients and gas required for cells to survive.
Alginate has been implicated in a variety of diverse applications including similar scaffolds that serve as a semi-organic protective “shell” for shielding stem cells on their way to an injury site. In combination with Graphene Oxide, Alginate has also been used to construct a flexible composite that can adapt to it’s surroundings by altering it’s density and size, while still remaining extremely durable.
The authors who participated in this study include Xiaowei Zhang, Gyeong Jin Kim, Min Gyeong Kang, Jung Ki Lee, Jeong Wook Seo, Jeong Tae Do, Kwonho Hong, Jae Min Cha, Su Ryon Chin and Hojae Bae.
cover photo: an example of another 3d bioprinted tissue scaffold from the University of Pittsburgh