TAGS: Inks
Researchers in the lab of Rice’s Jeffrey Hartgerink have figured out how to 3D-print the well-defined structures using a self-assembling peptide ink.
Using Peptides as Base Material
“
Eventually, the goal is to print structures with cells and grow mature tissue in a petri dish. These tissues can then be transplanted to treat injuries, or used to learn about how an illness works and to test drug candidates,” said Adam Farsheed, a Rice bioengineering graduate student and lead author of the study, which appeared in Advanced Materials.
“
In this work, we used peptides as our base material in our 3D-printing inks,” continued Farsheed. Developed by Hartgerink and collaborators, these “
multidomain peptides” are designed to be hydrophobic on one side and hydrophilic on the other. When placed in water, “
one of the molecules will flip itself on top of another, creating what we call a hydrophobic sandwich,” explained Farsheed.
These sandwiches stack onto one another and form long fibers, which then form a hydrogel, a water-based material with a gelatinous texture that can be useful for a wide range of applications such as tissue engineering, soft robotics and wastewater treatment.
Multidomain peptides have been used for nerve regeneration, cancer treatment and wound healing, and have been shown to promote high levels of cell infiltration and tissue development when implanted in living organisms.
Reassembling After Deformation
“
We know that the multidomain peptides can safely be implanted in the body,” Farsheed shared. “
But what I was looking to do in this project was to go in a different direction and show that these peptides are a great 3D-printing ink.”
“
It might be counterintuitive since our material is so soft, but I recognized that our multidomain peptides are an ideal ink candidate because of the way they self-assemble,” Farsheed noted. “
Our material can reassemble after being deformed, similar to how toothpaste forms a nice fiber when pushed out of a tube.”
“
I had more of a brute-force engineering approach where instead of chemically modifying the material to make it more amenable to 3D printing, I tested to see what would happen if I simply added more material,” Farsheed commented. “
I increased the concentration about fourfold, and it worked extremely well.”
Controlling Cell Behavior Using Structural & Chemical Complexity
“
There have been only a handful of attempts to 3D-print using other self-assembling peptides, and that work is all great, but this is the first time that any self-assembling peptide system has been used to successfully 3D-print such complex structures,” stated Farsheed.
The structures were printed with either positively charged or negatively charged multidomain peptides, and immature muscle cells placed on the structures behaved differently depending on the charge. Cells remained balled up on the substrate with a negative charge, while on the positively charged material the cells spread out and began to mature.
“
It shows that we can control cell behavior using both structural and chemical complexity,” Farsheed added.
The National Institutes of Health (R01 DE021798) and the National Science Foundation Graduate Research Fellowships Program supported the research.
Source: Rice University