Congratulations to Sohyun! She defended her Ph.D. in Aug 2021 and is set to join Novavax Inc. Sohyun was co-advised by Prof. Bill Bentley from BioE – so she got to work with both capsules and microbes! Her excellent paper on capsules with embedded cells was published recently in ACS-AMI.
Can we use electric fields to modulate soft materials? This is an area in which we have made several contributions. First, we developed electroformation as a way to make gels with precise shape in 3D (see above). It could allow tissues to be 3D-bioprinted without the need for a printer. Next, we have discovered electroadhesion, which allows gels to be adhered to biological tissues by applying a field. This could enable a simpler way to do surgeries in the future.
Stopping blood loss from wounds is crucial during surgeries and on the battlefield. We got into this area when we found a ‘hemostatic’ polymer that converts liquid blood into a gel (see above movie) by self-assembly. Thus, the polymer is able to stop bleeding from severe injuries. This technology won Invention of the Year at UMD in 2009, and since then has been patented and FDA-approved. Medcura, has brought this to the market in 2021.
2. S. H. Ahn, M. Rath,…W. Bentley, S. R. Raghavan
Single-step synthesis of alginate gels with a covalent shell: A simple way to protect encapsulated cells.
ACS Applied Materials & Interfaces, 13, 18432 (2021)
We have discovered that cationic gels can be adhered to animal tissues by placing gel and tissue in an electric field (DC, 10 V) for 20 seconds. Applying the DC field with reversed polarity reverses the adhesion. Such electroadhesion can be used to seal cuts or tears in tissues. Our studies suggest that electroadhesion could be potentially used for performing surgery without the need for sutures.
Gels that absorb a lot of water are used in many products, such as diapers. This paper described a new superabsorbent gel that beat the world record for water-absorption – it could absorb 3000 times its weight in water. The gel could be easily made in the lab and it was also strong. Our recipe has been used by numerous researchers around the world.
Fruits and vegetables retain water because they are covered by a hydrophobic skin. In this paper, we devised a way to form a hydrophobic “skin” around hydrogels. The skin is thin, transparent and peelable. For a gel in water, the skin protects it from acids or microbes. For a gel exposed to air, the skin helps resist drying. Skin-covered gels could be used in robotics or other areas.
Oil spills on the ocean are usually cleared by spraying dispersants, but these can be toxic. We developed the first food-grade, non-toxic dispersant in this paper. It is based on lecithin (a lipid used in chocolate) and Tween 80 (a surfactant used in ice cream). The two work synergistically to form stable emulsions of crude oil in seawater.