AsianScientist (Dec. 28, 2015) – Scientists have created a mechanically durable hydrogel inspired by the behavior of sea anemones. Their findings, published in Biomacromolecules, stemmed from the observation that sea anemones’ body length and width varies almost ten-fold by shrinking rapidly and expanding slowly under stimulus. The team assumed that a mechanically durable protein in its body could play an important role in contraction and relaxation.
Hydrogels are a 3D network of hydrophilic polymers that have excellent swelling properties, enabling them to absorb ten to thousand times of its dry weight in water. The water-capturing capacity of hydrogels gives them a soft and rubber-like flexibility, and allow them to provide a constant nutrient supply to cells. These advantages make hydrogels suitable as an extracorporeal bio-artificial organ, space filling material or delivery vehicle.
However, hydrogels face some limitations in handling, sterilization, and mechanical properties. The latter has been considered as the one distinct drawback in hydrogel research.
In the present study, a team of researchers led by Professor Hyung Joon Cha, of the Pohang University of Science and Technology’s (POSTECH) Department of Chemical Engineering have developed a mechanically durable hydrogel based on the sea anemone protein aneroin.
Aneroin is rich in the amino acid tyrosine, which allowed the researchers to form tyrosine-tyrosine bonds. These dityrosine-linkages contribute to durable structures in nature including the jumping pad of dragonflies and fertilization membranes of sea urchin. This in turn contributed to a mechanically improved hydrogel.
Through a photo-initiated dityrosine crosslinking method, the aneroin solution was transformed into a 3D hydrogel-based scaffold in a few seconds. Mechanically, the aneroin hydrogel exhibited significantly stronger and stiffer properties than those of collagen, gelatin, and elastin, which have already been widely exploited as hydrogel materials. It also exhibited approximately four-fold stronger mechanical properties compared with silkworm silk.
Biologically, the aneroin hydrogel provided an adequate environment for cell growth. Mammalian cells inside the hydrogel proliferated well with an appropriate cell size and healthy morphology. Dead cells were barely detectable in the hydrogel.
The mechanically durable and biologically compatible aneroin hydrogel showed clear advantages and could be used in various biomedical applications, especially for cell-containing biomaterials, cell-carrier patches, bio-artificial grafts, and burn dressing materials.
The article can be found at: Yang et al. (2015) Mechanically Durable and Biologically Favorable Protein Hydrogel Based on Elastic Silklike Protein Derived from Sea Anemone.
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Source: Pohang University of Science and Technology; Photo: Jeff Kubina/Flickr/CC.
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