Using an amino acid, rice university chemists found the sticky feet of mussels to make those fibers line up into strong hydrogel strings.
Rice graduate student I-Che Li said, the hydrogel strings can be picked up and moved with tweezers, and expects they will help labs gain better control over the growth of cell cultures.
In previous, researchers developed synthetic hydrogels that could be injected into the body to serve as scaffolds for tissue growth.
The hydrogels contained hydrophobic peptides that self-assembled into fibers about 6 nanometers wide and up to several microns long. However, the fibers did not interact with one other, because they generally appeared in microscope images as a tangled mass.
Researchers developed a process that would be easier if the material was water soluble. So, they added a chain of amino acids known as DOPA to the sides of the fibers to allow them to remain water-soluble in the syringe.
DOPA also known as 3,4-dihydroxyphenylalanine is the compound that lets mussels stick to just about anything. Researchers found that the combination of DOPA and shear stress from passing through the needle prompted the fibers to form visible, rope-like bundles.
DOPA promoted chemical cross-linking reactions that helped the bundles hold their shape. DOPA is really sensitive to oxidizing agents. Even exposing DOPA to air oxidizes it, and that aids in cross-linking the fibers.
The aligned fibers also proved to have a curious and useful optical property called uniform birefringence, or double-refraction. Researchers can see where the aligned fibers are, even if they’re covered by cells.
The aligned fibers can also be used for macroscale medical applications but with nanoscale control over the structures.
More information: [JACS]