Researchers at the University of Illinois and the University of Massachusetts, Amherst have taken the first steps toward gaining control over the self-assembly of synthetic materials in the same way that biology forms natural polymers. This advance could prove useful in designing new bioinspired, smart materials for applications ranging from drug delivery to sensing to remediation of environmental contaminants.
Proteins, which are natural polymers, use amino acid building blocks to link together long molecular chains. The specific location of these building blocks, called monomers, within these chains creates sequences that dictate a polymer’s structure and function. In the journal Nature Communications, the researchers describe how to utilize the concept of monomer sequencing to control polymer structure and function by taking advantage of a property present in both natural and synthetic polymers – electrostatic charge.
“Proteins encode information through a precise sequence of monomers. However, this precise control over sequence is much harder to control in synthetic polymers, so there has been a limit to the quality and amount of information that can be stored,” said Charles Sing, a professor of chemical and biomolecular engineering at Illinois and a study co-author. “Instead, we can control the charge placement along the synthetic polymer chains to drive self-assembly processes.”
“Our study focuses on a class of polymers, called coacervates, that separate like oil and water and form a gel-like substance,” said Sarah Perry, a study co-author and University of Massachusetts, Amherst chemical engineering professor, as well as an Illinois alumna. She received her PhD in 2010, advised by Dr. Paul Kenis.
Through a series of experiments and computer simulations, the researchers found that the properties of the resulting charged gels can be tuned by changing the sequence of charges along the polymer chain.
“Manufacturers commonly use coacervates in cosmetics and food products to encapsulate flavors and additives, and as a way of controlling the ‘feel’ of the product,” Sing said. “The challenge has been if they need to change the texture or the thickness, they would have to change the material being used.”
Sing and Perry demonstrate that they can rearrange the structure of the polymer chains by tuning their charge to engineer the desired properties. “This is how biology makes the endless diversity of life with only a small number of molecular building blocks,” Perry said. “We envision bringing this bioinspiration concept full circle by using coacervates in biomedical and environmental applications.”
The results of this research open a tremendous number of opportunities to expand the diversity of polymers used and the scale of applications, the researchers said. “Currently, we are working with materials on the macro scale – things that we can see and touch,” Sing said. “We hope to expand this concept into the realm of nanotechnology, as well.”
The National Science Foundation and the U. of I. Graduate College supported this research.
Written by Lois Yoksoulian, Physical Sciences Editor, University of Illinois News Bureau
To reach Charles Sing, call 217-244-6671; firstname.lastname@example.org.
To reach Sarah Perry, call 413-545-6252; email@example.com.
The paper “Sequence and entropy-based control of complex coacervates” is available online and from the U. of I. News Bureau. DOI: 10.1038/s41467-017-01249-1
Two Chemical and Biomolecular Engineering undergraduates were recently named recipients of 2017 Beckman Institute student awards.
Founded in the 1980s, the Beckman Institute for Advanced Science and Technology is intended to pursue new methods of multidisciplinary research at the university. It’s devoted to leading-edge research in the physical sciences, computation, engineering, biology, behavior, cognition, and neuroscience.
Dongkwan Lee was awarded the Beckman Institute Undergraduate Fellowship. He is studying chemical and biomolecular engineering with a minor in electrical and computer engineering. He plans to work with Rohit Bhargava, a professor of bioengineering, affiliate professor of ChBE, and member of the Bioimaging Science and Technology Group, on a project called “Attenuated Total Reflectance Using Quantum Cascade Lasers for Fast, Sub-Diffraction-Limited Chemical Imaging.”
Supported by funding from the Arnold and Mabel Beckman Foundation, the Beckman Institute Undergraduate Fellowships offer undergraduates the opportunity to pursue interdisciplinary research at the institute during the summer.
ChBE student Michael Jorgensen was given the Neurotechnology for Memory and Cognition Award. His research proposal, “Development of Photoacoustic Probes for Nitric Oxide Imaging,” will be directed by Jefferson Chan, an assistant professor of chemistry and member of the Bioimaging Science and Technology Group.
The Neurotechnology for Memory and Cognition Awards, supported by funding from the Arnold and Mabel Beckman Foundation, offers at least one Illinois graduate student and one Illinois undergraduate student the opportunity to pursue interdisciplinary research in neuroscience and technology development at the Beckman Institute during the summer.
On May 14, 2017, 139 seniors graduated with a bachelor’s degree in Chemical Engineering, four students received their master’s and five received their doctoral degrees. This year’s convocation was especially notable because the department invited graduate students to the ceremony. Following tradition, faculty advisors placed doctoral hoods over the heads of graduate students, marking their students’ successful completion of the program.
Dr. Elmer Dougherty delivered this year’s convocation remarks. A Kansas native, Dr. Dougherty earned his bachelor’s degree from the University of Kansas in 1950 and his MS and PhD degrees from the University of Illinois in 1951 and 1955, all in Chemical Engineering. As a graduate student, he studied under the legendary Professor Harry Drickamer. After graduate school, he worked at Esso and Dow (where he wrote his first computer program in 1955), as well as Union Carbide and Chevron. Along the way he also formed two software companies.
In 1971, Dr. Dougherty joined academia and became a Chemical Engineering Professor at the University of Southern California. He retired from USC in 1995. He continues to be involved in his company, Maraco, an oil and gas software development firm that he established in 1979. He has consulted around the globe and he has written over 50 technical papers. A distinguished member of the Society of Petroleum Engineers, he received its prestigious Cedric Ferguson Medal. In 2006, the University of Kansas Chemical Engineering Department inducted him into its Alumni Hall of Fame.
In his address, Dougherty told students that their integrity is a “badge of dependability and trust.”
“If you remember nothing else I say today, remember this. If your boss asks you a question and you do not know the answer, do not, I repeat, do not babble gibberish. Say, ‘I don’t know. But I’ll find out. When do you need the answer?’”
Dougherty advised students to continue honing their communication skills and to express ideas simply and concisely. He also told them that every day of their professional life, “a jury of your peers and superiors is judging you.”
“Before you act, remember your physics, chemistry, and engineering. Does it compute? If it doesn’t, reboot. You only succeed if you get things done, but you must consider the risk,” he said.
In his speech Dr. Dougherty also reflected on his time on campus and the excellent teachers he had, including chemical engineering giants James Westwater, Harry Drickamer, and Tom Hanratty.
“Go out and make your mentors proud of the results of this slice of their life’s work,” he advised.
Feng Sheng Hu, dean of the College of Liberal Arts & Sciences, said students should be immensely proud of themselves for having succeeded in one of the most rigorous programs on campus, one with a longstanding record of excellence, home to award-winning teachers and researchers working at the forefront of their disciplines. As members of the College of Liberal Arts and Sciences, they are also joining a community of more than 160,000 alumni around the world, graduates who have distinguished themselves in business, medicine, research, and many other areas.
“Be a force for good and a strong advocate for your alma mater,” he said.
Department Head Dr. Paul Kenis said he and fellow faculty and staff wished students success in their pursuits and best of luck in their personal and professional lives. He also urged them to stay in touch with the department and he looked forward to hearing news of their accomplishments.
A reception was held in a tent on Centennial Plaza, between Noyes Laboratory and the Chemistry Annex.
Congratulations to Chemical and Biomolecular Engineering graduate student Megan Witzke, who has been selected to receive the TechnipFMC Fellowship for 2017-2018.
Witzke is a member of Assistant Professor David Flaherty’s lab. Her research aims to improve the catalytic conversion of biomass derivatives to higher value chemicals by determining the reaction mechanism and underlying factors that control catalyst selectivity.
She entered the ChBE graduate program in Fall 2013 after earning a BS in Chemical Engineering from Case Western.
The fund was originally created by Bert A. Gayman, a mechanical engineering graduate of the University of Illinois with a gift of shares of Chicago-based Link-Belt Company, later acquired by FMC Corporation. FMC recently merged with Technip to create TechnipFMC, a global leader in subsea, onshore/offshore and surface projects. The fund supports scholarships, fellowships and research.
Congratulations to Chemical and Biomolecular Engineering graduate student Thao Ngo, who was selected to participate in the 67th Lindau Nobel Laureate Meeting this summer.
Ngo is a graduate student in Richard C. Alkire Professor Hong Yang’s research group. Her research focuses on studying the growth and dissolution of Pt-based nano catalysts using in situ electron microscopy and x-ray based techniques.
Ngo is a National Science Foundation Graduate Research Fellow who received her B.S. in Chemical Engineering from Arizona State University in 2013. She joined the department in Fall 2013.
The 67th Lindau Meeting will focus on chemistry and take place in June 2017. Ngo is the only awardee from the University of Illinois to be invited to the scientific conference this year. She will represent the U.S. there.
The Lindau Nobel Laureate Meetings aim to foster exchange among scientists of different generations, cultures, and disciplines. Since they began in 1951, the meetings have become an international forum for scientific exchange, bringing together Nobel Laureates and the next generation of leading scientists, including post-doctoral researchers and graduate and undergraduate students from around the world.
For additional information on the Lindau Nobel laureate meeting, visit www.lindau-nobel.org/.
Researchers at the University of Illinois report they can alter blood cell development through the use of biomaterials designed to mimic characteristics of the bone marrow.
The findings, reported in the journal Science Advances, are a first step toward developing more effective bone marrow treatments for diseases like leukemia and lymphoma.
Blood cells flow throughout the body delivering life-supporting oxygen and nutrients. As these cells are used and recycled they are regenerated by bone marrow, the soft tissue inside the body’s long and hollow bones.
Certain regions of bone marrow contain hematopoietic stem cells, the precursors of all blood and immune cells, said University of Illinois chemical and biomolecular engineering professor Brendan Harley, who led the research with postdoctoral researcher Ji Sun Choi.
“The tissue environment that surrounds these cells in the bone marrow provides a wealth of signals that can alter how these precursor cells behave. This paper looked at the signals provided by the tissue matrix itself,” said Harley, who also is affiliated with the Carl R. Woese Institute for Genomic Biology at the U. of I.
One of the major tools that oncologists use to treat leukemia and lymphoma involves transplanting HSCs. The donor stem cells must locate marrow cavities and start producing blood and immune cells. However, there is a limited quantity of available donor HSCs and the success rate of transplantation is low.
“We’re interested in this problem from an engineering standpoint,” Harley said. “The goal is to create better tools to both expand the number of donor HSCs and improve their capacity to repopulate the bone marrow after transplantation.”
Like cells throughout the body, HSCs are contained in a three-dimensional tissue environment known as the extracellular matrix. Harley and Choi gathered samples of HSCs from mice and then grew them in the laboratory using biomaterials engineered to mimic some of the extracellular matrix properties of the native bone marrow. Their goal was to examine how these engineered systems could alter the HSCs’ capacity to proliferate and differentiate to become blood cells.
The researchers examined two main elements of the matrix that regularly interact with HSCs: collagen and fibronectin. They found that the HSCs that were exposed to collagen proliferated more rapidly but that they had differentiated, meaning they were no longer stem cells. When exposed to fibronectin, the stem cells proliferated less rapidly, but were able to maintain their stem cell-like nature.
“With the collagen substrates, we got more cells but not useful cells,” Harley said. “With the right combination of stiffness in the matrix and the presence of fibronectin, we identified a class of biomaterials that show promise for being able to maintain and eventually expand these stem cells outside of the body. An engineered bone marrow will be of enormous value for treating hematopoietic cancers such as leukemia, but also for understanding the process of bone marrow failure and other hematopoietic diseases.”
This project is only the first step in controlling the signals from the matrix that influence HSCs, Harley said. He and other researchers in his lab are currently investigating other features of the matrix that can be manipulated to increase the number of stem cells and make them more effective in transplantation.
The National Science Foundation, National Institutes of Health and the American Cancer Society of Illinois supported this research.
by Sarah Banducci, University of Illinois News Bureau Intern
To reach Brendan Harley, call 217-244-7112; email firstname.lastname@example.org.
Research by Professor of Chemical and Biomolecular Engineering Huimin Zhao and graduate student Behnam Enghiad is pioneering a new method of genetic engineering for basic and applied biological research and medicine. Their work, reported in ACS Synthetic Biology, has the potential to open new doors in genomic research by improving the precision and adherence of sliced DNA.
“Using our technology, we can create highly active artificial restriction enzymes with virtually any sequence specificity and defined sticky ends of varying length,” said Zhao. “This is a rare example in biotechnology where a desired biological function or reagent can be readily and precisely designed in a rational manner.”
Restriction enzymes are essential tools for recombinant DNA technology that have revolutionized modern biological research, however have limited sequence specificity and availability. The Pyrococcus furiosus Argonaute (PfAgo) based platform for generating artificial restriction enzymes (AREs) is capable of recognizing and cleaving DNA sequences at virtually any arbitrary site and generating defined sticky ends of varying length.
Restriction enzymes are an important tool in genomic research: by cutting DNA at a specific site, they create a space wherein foreign DNA can be introduced for gene-editing purposes. This process is not only achieved by naturally-occurring restriction enzymes; other artificial restriction enzymes, or AREs, have risen to prominence in recent years. CRISPR-Cas9, a bacterial immune system used for “cut-and-paste” gene editing, and TALENs, modified restriction enzymes, are two popular examples of such techniques.
Though useful in genetic engineering, no AREs generate defined “sticky ends”—an uneven break in the DNA ladder-structure that leaves complementary overhangs, improving adhesion when introducing new DNA. “If you can cleave two different DNA samples with the same restriction enzyme, the sticky ends that are generated are complementary,” explained Enghiad. “They will hybridize with each other, and if you use a ligase, you can stick them together.”
However, restriction enzymes themselves have a critical drawback: the recognition sequence which prompts them to cut is very short—usually only four to eight base pairs. Because the enzymes will cut anywhere that sequence appears, researchers rely on finding a restriction enzyme whose cut site appears only once in the genome of their organism or plasmid—an often difficult proposition when the DNA at hand might be thousands of base pairs long.
This problem has been partially solved simply by the sheer number of restriction enzymes discovered: more than 3600 have been characterized, and over 250 are commercially available. “Just in our freezer, for our other research, we have probably over 100 different restriction enzymes,” said Enghiad. “We look through them all whenever we want to assemble something … the chance of finding the unique restriction site is so low.
“Our new technology unifies all of those restriction enzymes into a single system consisting of one protein and two DNA guides. Not only have you replaced them, but you can now target sites that no available restriction enzymes can.”
Enghiad and Zhao’s new technique creates AREs through the use of an Argonaute protein (PfAgo) taken from Pyrococcus furiosus, an archeal species. Led by two DNA guides, PfAgo is able to recognize much longer sequences when finding its cut site, increasing specificity and removing much of the obstacles posed by restriction enzymes. Further, PfAgo can create longer sticky ends than even restriction enzymes, a substantial benefit as compared to other AREs.
“When we started, I was inspired by a paper about a related protein—TtAgo. It could use DNA guides to cleave DNA, but the protein is only active at temperatures up to 75 degrees,” explained Enghiad. “DNA strands start to separate at temperatures higher than 75 degrees, which could allow Ago proteins to cleave double stranded DNA. If there were a protein that was active at higher temperatures, I reasoned, that protein could be used as an artificial restriction enzyme.
“So I started looking for that, and what I found was PfAgo.”
In addition to replacing restriction enzymes in genetic engineering processes, Enghiad and Zhao believe their technology will have broad applications in the biological research. By creating arbitrary sticky ends, PfAgo could make assembly of large DNA molecules easier, and enables cloning of large DNA molecules such as biochemical pathways and large genes.
The application of these techniques is broad-reaching: ranging from discovery of new small molecule drugs to engineering of microbial cell factories for synthesis of fuels and chemicals to molecular diagnostics of genetic diseases and pathogens, which are the areas Zhao and Enghiad are currently exploring.
“Due to its unprecedented simplicity and programmability (a single protein plus DNA guides for targeting), as well as accessibility … we expect PfAgo-based AREs will become a powerful and indispensable tool in all restriction enzyme or nuclease-enabled biotechnological applications and fundamental biological research,” said Zhao. “It is to molecular biology as the CRISPR technology is to cell biology.”
Written by Kathryne Metcalf of the Carl R. Woese Institute for Genomic Biology.
Charles E. Sing, Assistant Professor of Chemical and Biomolecular Engineering at the University of Illinois, has received a 2017 National Science Foundation CAREER Award for his proposal, “Developing the design rules of charge sequence to inform polymer self-assembly.”
The National Science Foundation’s Faculty Early Career Development Program’s CAREER Awards are prestigious and competitive awards given to junior faculty who exemplify the role of teacher-scholar through outstanding research, excellent education, and the integration of education and research within the context of the mission of their respective organizations. The program will provide five years of support.
“I am incredibly honored by this award. I think it reflects the exciting ideas and hard work of my students, and I am excited to keep working with them to explore this new area of charged, patterned polymers. I hope we can live up to this recognition and push the field forward,” Sing said.
Dr. Sing aims to enable advances in materials that demand structural precision at the nano-level, such as fuel cell membranes, functional coatings and sensors, and drug delivery vehicles.
His research is inspired by the sophisticated precision of biological systems made from large molecules that specifically and exclusively interact using information encoded in patterns of electrostatic charge. He will investigate whether polymers—long chain-like molecules made of joined molecular units called monomers—that self-organize can be made to behave in a similar way. He and his research group will determine how patterns of electrostatically charged monomers along a polymer molecular chain can be designed to guide the self-organization of molecular structures at the nanometer length scale.
The NSF CAREER award will also support outreach efforts. Sing and his graduate and undergraduate students volunteer with the St. Elmo Brady STEM Academy, which aims to boost interest in STEM among underrepresented minorities. They teach elementary-age students about issues such as sustainability and the lifecycle of plastics and introduce them to interactive computer simulation activities.
Sing joined the Department of Chemical and Biomolecular Engineering faculty in 2014. He received his BSE/MS from Case Western Reserve University and his PhD from the Massachusetts Institute of Technology. His postdoctoral work was at Northwestern University’s International Institute for Nanotechnology.
Congratulations to postdoctoral fellow Lydia Kisley, who was featured in the Forbes 30 Under 30 List for 2017.
The annual list highlights innovators who are under 30 years old and work in a variety of different industries, from media to manufacturing. Kisley was included on the healthcare list.
Kisley, 28, is a Beckman-Brown Interdisciplinary Postdoctoral Fellow at the University of Illinois. She works with several researchers on campus, including Deborah Leckband, Reid T. Milner Professor of Chemical Sciences; Martin Gruebele, James R. Eiszner Chair in Chemistry and Chemistry Department Head; and Paul Braun, Ivan Racheff Professor of Materials Science and Engineering.
With her research she aims to “inspire and design materials and biomaterials in smarter ways by using unique microscopy in order to understand them better.”
Kisley received her PhD in Chemistry in 2015 from Rice University. Her bachelor’s degree is from Wittenberg University in Ohio.
Since arriving at Illinois in 2015, she has worked with polymers and hydrogels, studying how proteins fold at the surface of a polymer brush (polymer chains grafted to a surface) or within a hydrogel, and observing how stable the proteins are and how they function. Her research has applications in biotechnology, particularly in biosensors, and development of medical devices.
As a graduate student at Rice, she explored ways to purify and separate drug molecules, with the goal of improving efficiency in pharmaceutical manufacturing. She and her fellow researchers also observed blood serum proteins combining with gold nanoparticles, prompting them to aggregate, a finding that has implications for nanoparticle toxicity issues. Gold nanoparticles have been used in some cancer treatments.
In addition to her research work, she has been involved in a number of outreach activities with organizations such as the Girl Scouts of Central Illinois and the Houston Museum of Natural Science.
Kisley intends to pursue a career in academia and to establish a research lab at a university where she can combine the skills she is learning at Illinois in understanding protein folding and surfaces and materials with skills she developed while pursuing her PhD, which entailed research at the single molecule level.
Congratulations to our December graduates!
The Department of Chemical and Biomolecular Engineering held a convocation ceremony on Friday, Dec. 16, 2016, for its December graduates. The ceremony featured Illinois Chemical Engineering alumnus George P. Nassos, who received his bachelor’s degree in 1961.
The Chicago native graduated from Austin High School and attended the University of Illinois at Navy Pier (now UI-Chicago) before transferring to Urbana-Champaign. After earning his BS in Chemical Engineering from Illinois, he went on to earn his MS and PhDs in Chemical Engineering from Northwestern University.
Dr. Nassos worked for International Minerals & Chemical Corp. (IMC) for 16 years, during which he earned an MBA from Northwestern. He advised graduates who are interested in business and pursuing MBAs to do so while working so they can apply what they learned in class to their jobs.
After earning his MBA, he served as an adjunct professor in Loyola University Chicago’s MBA program until IMC transferred him to its European subsidiaries. Living and working in Europe was one of the best decisions he made, Dr. Nassos recalled in his convocation speech. It was in Europe where his interest in energy and the environment developed as he saw how Germany and other countries had already adapted technologies such as escalators that power on and off in response to users stepping on and off them.
After his time with IMC, Dr. Nassos worked for Chemical Waste Management, the hazardous waste subsidiary of Waste Management, where he developed treatment and disposal technologies such as fuel pellets from non-recyclable waste.
Next he pursued his interest in teaching at the graduate business school level. Dr. Nassos was named director of the top-ranked MS in Environmental Management & Sustainability program at the Illinois Institute of Technology Stuart School of Business. He taught the sustainability capstone course and authored the textbook, Practical Sustainability Strategies: How to Gain a Competitive Advantage. Dr. Nassos managed the program until he retired in 2011.
Currently he is principal of George P. Nassos & Associates, a consulting company focusing on environmental sustainability and renewable energy. Dr. Nassos also is president of Sustainable Energy Systems, which markets a new onsite waste-to-energy technology.
When people ask him if he’s retired or still working, “I say, ‘yes,’” Nassos said, prompting laughs at the ceremony.
“I still have my health, energy and passion for what I’m doing,” he told the audience.
Dr. Nassos urged the new graduates to have passion for what they’re doing and to remember they’re “only on this earth for so much time.”
“Time is your most valuable asset. Make the most of it.”