Prof. Srinivasa R. Raghavan
Patrick & Marguerite Sung Professor
Dept. of Chemical & Biomolecular Engineering
University of Maryland, College Park
Office: 1227C Chem-Nuc Building
Phone: (301) 405-8164
Email: sraghava@umd.edu
Bio | CV | Google Scholar
Group Members
Featured Group Member
Niti defended her Ph.D. proposal in Dec 2018. She has made a key discovery that some surfactants can self-assemble into long chains (called ‘wormlike micelles’) in polar solvents like glycerol. Niti has also designed food-grade dispersants for the cleanup of oil spills.
Niti Agrawal
Featured Group Alumna
Kerry defended her Ph.D. in Chemistry in Aug 2018, after which she joined Gelest Inc. in Philadelphia. In her Ph.D. work, Kerry studied how to endow polymer capsules with ‘emergent‘ properties as a result of internal chemical reactions. Kerry won several departmental awards for her work and is a co-author on 3 publications.
Kerry DeMella
What We Do
We create and invent new materials with unusual or exceptional properties. Read an interview with Prof. Raghavan…
The materials we create are usually soft solids or viscous fluids. We try to tailor their mechanical and flow properties. More…
Our specialty is “smart” materials, whose properties can be switched (by light, heat, electricity, etc.). More…
Our inventions often draw inspiration from nature at various length scales (macro, micro, nano). More…
We emphasize simplicity in our work. That is, we try to find simple routes to new materials using cheap ingredients. More…
Our scientific focus is on discovering the rules for molecular self-assembly into various nanoscale structures. More…
Techniques in which we have expertise include rheology, light scattering, and neutron scattering (SANS). More…
Research Areas Connected to the Group
Colloid Science & Polymer Science
Featured Research Topic: Artificial Cells
The architecture of life is based on cells (microscale containers), which have organelles, i.e., smaller containers inside them. We are trying to mimic this by creating microscale capsules that have smaller capsules inside them. These multicompartment capsules (MCCs) can contain nanoparticles, enzymes, or bacteria in specific inner compartments (see paper in Chemical Science, 2017). We are collaborating with Prof. Bill Bentley (BioE) in this research.
Applications of Interest to the Group
Featured Application: Stopping Bleeding
Stopping blood loss from wounds is crucial during surgeries and on the battlefield. We got into this area when we discovered a ‘hemostatic’ polymer that is able to convert liquid blood into a gel (see above) by a self-assembly mechanism. The same polymer rapidly arrests bleeding from severe injuries in animal models. This technology won the Invention of the Year award at UMD in 2009, and since then has been patented and FDA-approved. Gel-e Inc., a company run by a former student, is bringing this to the market.
Did you know?
Three startup companies have been launched from our lab (Gel-e, GripBoost, Prasidiux).
Did you know?
Our lab is credited with the first biomedical device invented at UMCP to receive FDA approval.
Did you know?
We developed the first food-grade dispersant that can be used to disperse oil spills into seawater.
Publications
Recent
1. S. Gharazi, B. C. Zarket, K. C. DeMella, S. R. Raghavan
Nature-inspired hydrogels with soft and stiff zones that exhibit a 100-fold difference in elastic modulus.
ACS Appl. Mater. Interfaces, 10, 34664 (2018)
2. J. C. Athas, C. P. Nguyen, S. Kummar, S. R. Raghavan
Cation-induced folding of alginate-bearing gels: An unusual example of folding along the long axis.
Soft Matter, 14, 2735 (2018)
3. C. Arya, C. A. Saez, H. Huang, S. R. Raghavan
Clustering of CD-functionalized microbeads by an amphiphilic biopolymer.
ACS Appl. Mater. Interfaces, 9, 37238 (2017)
4. A. X. Lu, H. Oh, J. Terrell, W. E. Bentley, S. R. Raghavan
A new design for an artificial cell: Polymer capsules with inner compartments that can harbor microbes.
Chemical Science, 8, 6893 (2017)
5. B. C. Zarket, S. R. Raghavan
Onion-like multilayered polymer capsules synthesized by a bioinspired inside-out technique.
Nature Communications, 8, 193 (2017)
6. A. Gargava, C. Arya, S. R. Raghavan
Smart hydrogel-based valves inspired by the stomata in plants.
ACS Appl. Mater. Interfaces, 8, 18430 (2016)
Full List
Nature-inspired hydrogels with soft and stiff zones that differ 100-fold in their modulus. (ACS AMI, 2018)
This paper shows how to create a hydrogel that has many zones, each of which has different mechanical properties. The gel above has four zones, which stretch to different extents. The modulus of the stiffest zone is 100 times the modulus of the softest zone. Our approach could be used to build realistic mimics of the spinal discs present between our vertebrae, which have a soft core and a stiff shell.
Featured Classic Publication (1)
Insights into molecular gelation from Hansen solubility parameters. (Soft Matter, 2014)
Many molecules (‘gelators’) self-assemble into long fibers, which entangle to form molecular gels. Such gelation occurs in some organic solvents, but not in others. But is it possible to predict if gelation would occur beforehand? This paper provided a framework to predict molecular gelation using thermodynamic parameters of the various solvents. The same framework has now been used by many researchers.
Featured Recent Publication (2)
Onion-like multilayered capsules synthesized by a bioinspired inside-out technique. (Nature Comm, 2017)
Many materials in nature, including the onion, the egg, and tissues in our body have multiple concentric layers. To mimic this architecture, a simple synthesis technique is shown in this paper. In the resulting multilayered capsules, the composition and thickness of each layer can be varied. Such capsules could be used for the controlled delivery of drugs, cosmetic ingredients, or agrochemicals.
Featured Classic Publication (2)
A simple class of photorheological fluids: Surfactant solutions with viscosity tunable by light. (JACS, 2007)
This paper showed for the first time how one could easily create a ‘photorheological fluid‘ in the lab, i.e., a fluid whose viscosity could be dramatically altered by shining light. The fluid contained molecules that self-assembled into long chains initially. Irradiation with UV light altered the geometry of the molecules, which made them re-assemble into tiny spheres. This caused a 10,000-fold drop in viscosity.
Did you know?
Our research been featured in news stories by two local TV stations and in a program that aired on the Discovery Channel titled “Stephen Hawking presents”.
Did you know?
More than 20 patents have been filed by UMD’s Office of Technology Commercialization based on inventions from our lab.
Did you know?
A polymer gel invented in our lab swells up to 3000 times its weight in water. This is a world record to our knowledge.