Ayse Asatekin, Tufts University
Host: Prof. Jay Werber
Membranes offer a highly energy-efficient, simple to operate, scalable and portable separation method for many applications, from water treatment to oil and gas processing to pharmaceutical manufacturing. Yet, their broader use is often limited by insufficient selectivity and/or fouling with complex feeds. There are no commercial membranes that can separate small molecules of similar size in the liquid phase based on their chemical properties. We aim to develop new synthetic polymer membranes that accomplish this by self-assemble and create structures that mimic key features of biological pores like ion channels and porins: Constricted pores <5 nm in diameter that confine permeation, lined with functional groups that interact with the target during passage. Our first approach utilized the self-assembly of zwitterionic amphiphilic copolymers (ZACs), synthesized from a hydrophobic and a zwitterionic monomer. When ZACs are coated onto a support to form a thin film composite (TFC) membrane, self-assembled zwitterionic domains act as a network of nanochannels for water permeation. Our first ZAC-based thin film composite (TFC) membranes were size-selective with an effective pore size of ~1.3-1.5 nm. These membranes are exceptionally fouling resistant. We then developed cross-linkable ZACs (X-ZACs), which enabled us to access smaller effective pore sizes, down to ~0.9 nm, where ion separations are possible. Our membranes with the smallest pore sizes exhibited unprecedented selectivity between equally charged anions, including the highest Cl–/F– selectivity in the literature. This selectivity arises from zwitterion-ion interactions, which affect both ion partitioning and ion diffusivity, further emphasized through nanoconfinement. This opens the door to novel membranes with novel selectivity between molecules and ions of similar size and charge, mediated through channel-solute interactions. More recently, we have been exploring new avenues to prepare membranes the self-assembled nanopores and fouling resistance of ZAC-based membranes, but expand the range of separations accessible. We have developed amphiphilic polyampholytes (APAs), where hydrophobic, anionic, and cationic monomers form a random/statistical terpolymer that is insoluble in water. This approach allows access to a very broad array of functional groups lining the effective nanopores of these membranes, opening the door for complex separations. Alternatively, we have formed amphiphilic polyelectrolyte complex (APEC) membranes by coating consecutive layers of two amphiphilic polyelectrolytes (i.e. water-insoluble copolymers combining a hydrophobic monomer with either an anionic or a cationic monomer). Interestingly, these bilayer membranes exhibit very small effective pore sizes as well as higher permeances, implying selectivity arises from the formation of polyelectrolyte complexes at a thin interface between these layers. These approaches demonstrate a versatile and highly customizable approach for developing novel high-performance membranes.
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Ayse Asatekin is an associate professor in the Chemical and Biological Engineering Department at Tufts University, and Steve and Kristen Remondi Faculty Fellow. She received bachelor’s degrees in chemical engineering and chemistry from the Middle East Technical University (METU) in Ankara, Turkey. She went on to receive her Ph.D. in chemical engineering through the Program in Polymer Science and Technology (PPST) at MIT. She pursued her post-doctoral work with Prof. Karen K. Gleason, also at MIT. She co-founded Clean Membranes, Inc., a start-up company that commercialized a membrane technology that she began developing during her doctoral research, and worked as its Principal Scientist before joining the Tufts faculty in 2012. Novel membrane technologies developed in her lab are currently being commercialized by ZwitterCo, Inc., where she serves as the Senior Scientific Advisor. She is a Senior Member of the National Academy of Inventors, and the recipient of the NSF CAREER Award, Massachusetts Clean Energy Council’s Catalyst Award, and the Turkish American Scientists and Scholars Young Scholar Award. Her research interests are in developing novel membranes for clean water and energy-efficient separations through polymer self-assembly. She is also interested in multi-functional membranes, controlling surface chemistry for biomedical applications, polymer science, and energy storage.
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Join author Jeff Karp to celebrate the launch of his much-anticipated new book, LIT: Life Ignition Tools. The event will feature a conversation between Jeff Karp and University of Toronto Professor Dr. Milicia Radisic, followed by a reading, Q&A, and signing.
About the Speakers
Jeff Karp, PhD, is an acclaimed mentor and biomedical engineering professor at Harvard Medical School and MIT, a Distinguished Chair at Brigham and Women’s Hospital, and a fellow of the National Academy of Inventors. He has dedicated his research to bioinspired medical problem-solving, and his lab’s technologies have led to the formation of twelve companies. The technologies they have developed include a tissue glue that can seal holes inside a beating heart; targeted therapy for osteoarthritis, Crohn’s disease, and brain disorders; “smart needles” that automatically stop when they reach their target; a nasal spray that neutralizes pathogens; and immunotherapy approaches to annihilate cancer. Dr. Karp is also head of innovation at Geoversity, Nature’s University, a rainforest conservancy located in one of the top biodiversity hotspots in the world. He was selected as the Outstanding Faculty Undergraduate Mentor among all faculty at MIT and the top graduate student mentor of Harvard-MIT students. Dr. Karp lives in Brookline, Massachusetts, with his wife, children, and two Cavalier King Charles spaniels.
Dr. Milica Radisic is a Professor at the University of Toronto, Tier 1 Canada Research Chair in Organ-on-a-Chip Engineering and a Senior Scientist at the Toronto General Research Institute. She is also Director of the NSERC CREATE Training Program in Organ-on-a-Chip Engineering & Entrepreneurship and a co-lead for the Center for Research and Applications in Fluidic Technologies. She is a Fellow of the Royal Society of Canada-Academy of Science, Canadian Academy of Engineering, the American Institute for Medical & Biological Engineering, Tissue Engineering & Regenerative Medicine Society as well as Biomedical Engineering Society. Her impressive accolades include being recognized in the MIT Technology Review Top 35 Under 35, as well as receiving the Queen Elizabeth II Diamond Jubilee Medal, NSERC E.W.R Steacie Fellowship, YWCA Woman of Distinction Award, Killam Fellowship, Acta Biomaterialia Silver Medal, and Humboldt Research Award to name a few. Her research focuses on organ-on-a-chip engineering and development of new biomaterials that promote healing and attenuate scarring.
About LIT: Life Ignition Tools
In the age of convenience, information overload, and endless exposure to stimuli, it’s easy to trudge through the motions of life, pressured, distracted, and seeking instant gratification. When this way of living becomes the norm, it can immobilize us, making it feel impossible to reclaim control of our lives with intention and enthusiasm.
In LIT (William Morrow; April 9, 2024), Harvard Medical School professor, Mass General Brigham and MIT researcher, and renowned bioinspirationalist Jeff Karp, PhD, teaches us to harness the vital wisdom and power of nature to place us into a lit state. Lit is a life magnifier, a heightened state of awareness that drives curiosity, connection, and energy. In short: being lit takes us off autopilot and helps us stay alert, present, and fully engaged.
Diagnosed with learning differences and ADHD at a young age, Karp persisted through nearly insurmountable struggles. After discovering that he could think about thinking at age seven, he became his own science experiment, tapping into the lit state through trial and error to achieve hyper-awareness and explore his curiosity, creativity, and connection to nature. Decades later, as a biotech innovator, husband, and father, lit continues to encourage opportunities for innovation in his professional and personal lives.
He has honed those methods into a diverse toolkit that he calls Life Ignition Tools (LIT), which help us:
- Break out of habitual thinking to discover our own imaginative power.
- Stimulate creativity and excitement at work.
- Integrate our spiritual and personal lives to repair and deepen our relationships.
- Navigate multiple streams of sensory input and manage information overload.
Lit has inspired Dr. Karp’s innovative medical discoveries such as surgical glue inspired by slugs, a diagnostic for cancer based on the tentacles of jellyfish, and surgical staples based on the quills of a porcupine – but you don’t have to be a scientist to live lit. Anyone can use these principles to redirect their lives with energy, focus, creativity, and motivation to create the lives they truly want to lead.