For almost any conceivable protein, corresponding antibodies can be developed to block it from binding or changing shape, which ultimately prevents it from carrying out its normal function. As such, scientists have looked to antibodies as a way of shutting down proteins inside cells for decades, but there is still no consistent way to get them past the cell membrane in meaningful numbers.
Now, Penn Engineering researchers have figured out a way for antibodies to hitch a ride with transfection agents, positively charged bubbles of fat that biologists routinely use to transport DNA and RNA into cells. These delivery vehicles only accept cargo with a highly negative charge, a quality that nucleic acids have but antibodies lack. By designing a negatively charged amino acid chain that can be attached to any antibody without disrupting its function, they have made antibodies broadly compatible with common transfection agents.
Beyond the technique’s usefulness towards studying intracellular dynamics, the researchers conducted functional experiments with antibodies that highlight the technique’s potential for therapeutic applications. One antibody blocked a protein that decreases the efficacy of certain drugs by prematurely ejecting them from cells. Another blocked a protein involved in the transcription process, which could be an even more fundamental way of knocking out proteins with unwanted effects.
The NAE describes the Frontiers of Engineering program as one that “brings together outstanding early-career engineers from industry, academia, and government to discuss pioneering technical work and leading-edge research in various engineering fields and industry sectors. The goal is to facilitate interactions and exchange of techniques and approaches across fields and facilitate networking among the next generation of engineering leaders.”
Bassett and Tsourkas fit the grant’s description, as their proposed research requires them to combine their different areas of expertise to push the state of the art in engineering. The pair plans to engineer a new class of nanoparticles that can sense and differentially react to particular chemicals in their biochemical environment. This new class of nanoparticles could allow scientists to better study cellular processes and could eventually have important applications in medicine, potentially allowing for more personalized diagnoses and targeted treatment of disease.
To design and create this type of nanoparticle is no small task. The research demands Bassett’s background in engineering quantum-mechanical systems for use as environmental sensors, and Tsourkas’ ability to apply these properties to nanoscale “theranostic” agents, which are designed to target treatments based on a patient’s specific diagnostic test results.
By combining forces, Bassett and Tsourkas hope to introduce a new nanoparticle tool into their fields and to connect even more people in their different areas to promote future interdisciplinary work.
Nanotechnology is enabling new materials and devices that work at sizes so small that individual atoms and molecules make a difference in their behavior. The field is moving so fast, however, that scientists from other disciplines can have a hard time using the fruits of this research without becoming nanotechnologists themselves.
“Based on a short survey we conducted, we found that many faculty members want to synthesize unique chemical compounds, such as imaging agents, drugs or nanoparticles, but they don’t have the expertise to produce these compounds themselves,” says Andrew Tsourkas, professor in Penn Engineering’s Department of Bioengineering and Director of the Chemical and Nanoparticle Synthesis Core. “As a result, these projects are often abandoned.”
Zhiliang Cheng, Ph.D., a research assistant professor in the Department of Bioengineering at the University of Pennsylvania, has received an R01 grant from the National Institute of Neurological Disorders and Stroke to study chronic pain. The grant, which provides nearly $1.7 million over the next five years, will support the work of Dr. Cheng, Bioengineering Professor Andrew Tsourkas, and Vice Provost for Education and Professor Beth Winkelstein, in developing a novel nanotechnology platform for greater effectiveness in radiculopathy treatment.
Based on the idea that phospholipase-A2 (PLA2) enzymes, which modulate inflammation, play an important role in pain due to nerve damage, the group’s research seeks to develop PLA2-responsive multifunctional nanoparticles (PRMNs) that could both deliver anti-inflammatory drugs and magnetic resonance contrast agents to sites of pain so that the molecular mechanisms at work in producing chronic pain can be imaged, as well as allowing for the closer monitoring of treatment.
This research builds on previous findings by Drs. Cheng, Tsourkas, and Winkelstein. In a 2011 paper, Drs. Tsourkas and Winkelstein used superparamagnetic iron oxide nanoparticles to enhance magnetic resonance imaging of neurological injury in a rat model. Based on the theory of reactive oxygen species playing a role in pain following neural trauma, a subsequent paper published in July with Sonia Kartha as first author and Dr. Cheng as a coauthor found that a type of nanoparticle called polymersomes could be used to deploy superoxide dismutase, an antioxidant, to sites of neuropathic pain. The current grant-supported study combines the technologies developed in the previous studies.
“To the best of our knowledge, no studies have sought to combine and/or leverage this aspect of the inflammatory and PLA2 response for developing effective pain treatment. We hypothesize that this theranostic agent, which integrates both diagnostic and therapeutic functions into a single system, offers a unique opportunity and tremendous potential for monitoring and treating patients with direct, clinically translational impact,” Dr. Cheng said.
Andrew Tsourkas, Ph.D., who is an associate professor in the Department of Bioengineering, cofounded PolyAurum LLC, a company using gold particles to develop technologies to improve cancer therapies, in 2015. Dr. Tsourkas founded the company with two faculty members from the Perelman School of Medicine: Jay Dorsey, M.D., Ph.D., and Dave Cormode, Ph.D., the latter of whom is also a secondary factory member in BE. The name PolyAurum combines the word polymer with aurum, the Latin word for “gold.” Gold has been found to be able to enhance the effects of radiation therapy in cancer without damaging healthy tissue.
Dr. Tsourkas’s work with his colleagues at PolyAurum was featured recently in the The Philadelphia Inquirer. Debra Travers, the CEO of PolyAurum and herself a cancer survivor, was interviewed by the newspaper for its business section.
According to the article, Drs. Tsourkas and Cormode
have worked to make gold more biocompatible, resulting in PolyAurum’s current technology, Dorsey said. The gold nanocrystals are contained in a biodegradable polymer that allows enough metal to collect in a tumor. The polymer then breaks down, releasing the gold for excretion from the body so that it does not build up in key organs.