Tag: laboratory medicine and pathology

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Leveraging the Body’s Postal System to Understand and Treat Disease

by Nathi Magubane

Microwell device with a solution in the reservoir (Image: Courtesy of David E. Reynolds)

Akin to the packages sent from one person to another via an elaborate postal system, cells send tiny parcels that bear contents and packaging material that serve key purposes: To protect the contents from the outside world and to make sure it gets to the right place via a label with an address. 

These packages are known as extracellular vesicles (EVs)—lipid-bound molecules that serve a variety of regulatory and maintenance functions throughout the body. They assist in the removal of unwanted materials within the cell, and they transport proteins, aid in DNA and RNA transfer, and promote tumorigeneses in cancerous cells. 

Given their myriad roles, EVs have taken center stage for many researchers in the biomedical space as they have the potential to improve current methods of disease detection and treatment. The main challenge, however, is accurately identifying the molecular contents of EVs while also characterizing the EVs, which, unlike other cellular components that are more homogenous, have more heterogeneity.

Now, a team of researchers at the University of Pennsylvania has developed a novel platform, droplet-free double digital assay, for not only profiling individual EVs but also accurately discerning their molecular contents. The researchers took the digital assay, which quantifies the contents of a molecule via binary metric—a 1 corresponds to the presence of a molecule and a zero to the lack thereof—and applies it to the EV. The work is published in Advanced Science.

The team was led by Jina Ko, an assistant professor with appointments in the School of Engineering and Applied Science and Perelman School of Medicine. “Our method allows for highly accurate quantification of the individual molecules inside an EV,” Ko says . “This opens up many doors in the realm of early disease detection and treatment.”

The researchers first compartmentalized individual EVs utilizing a microwell approach to isolate the EVs. Next, they captured individual molecules within the EVs and amplified the signal for clarity. The team then was able to determine the expression levels of pivotal EV biomarkers with remarkable precision via fluorescence.

Read the full story in Penn Today.

Jina Ko is an assistant professor in the Department of Pathology and Laboratory Medicine in the Perelman School of Medicine and an assistant professor in the Department of Bioengineering in the School of Engineering and Applied Science at the University of Pennsylvania.

David Reynolds is a Ph.D. candidate in the Department of Bioengineering in Penn Engineering.

Other authors include, Menghan Pan, George Galanis, Yoon Ho Roh, Renee-Tyler T. Morales, Shailesh Senthil Kumar, and Su-Jin Heo of the Department of Bioengineering at Penn Engineering; Jingbo Yang and Xiaowei Xu of the Department of Pathology and Laboratory Medicine at Penn Medicine; and Wei Guo of the Department of Biology in the School of Arts & Sciences at Penn.

The research was supported by the National Institutes of Health: grants R00CA256353, R35 GM141832, and CA174523 (SPORE).

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Two Penn Bioengineers Receive NIH Director Award

by Nathi Magubane

Jina Ko (left) and Kevin Johnson (right), both from the School of Engineering and the Perelman School of Medicine with appointments in Bioengineering, have received the National Institute of Health Director’s Award to support their “highly innovative and broadly impactful” research projects through the High-Risk, High-Reward program.

The National Institutes of Health (NIH) has awarded grants to three researchers from the University of Pennsylvania through the NIH Common Fund’s High-Risk, High-Reward Research program. The research of Kevin B. Johnson, Jina Ko, and Sheila Shanmugan will be supported through the program, which funds “highly innovative and broadly impactful” biomedical or behavioral research by exceptionally creative scientists.

The High-Risk, High-Reward Research program catalyzes scientific discovery by supporting highly innovative research proposals that, due to their inherent risk, may struggle in the traditional peer-review process despite their transformative potential. Program applicants are encouraged to think “outside the box” and pursue trail-blazing ideas in any area of research relevant to the NIH’s mission to advance knowledge and enhance health.

Two Penn Bioengineering faculty, Johnson and Ko, are among 85 recipients for 2023.

Johnson, the David L. Cohen University Professor of Pediatrics, is a Penn Integrates Knowledge University Professor who holds appointments in the Department of Computer and Information Science in the School of Engineering and Applied Science and the Department of Biostatistics, Epidemiology, and Informatics in the Perelman School of Medicine. He also holds secondary appointments in Bioengineering, Pediatrics, and in the Annenberg School for Communication. He is widely known for his work with e-prescribing and computer-based documentation and, more recently, work communicating science to lay audiences, which includes a documentary about health-information exchange. Johnson has authored more than 150 publications and was elected to the American College of Medical Informatics, Academic Pediatric Society, National Academy of Medicine, International Association of Health Science Informatics, and American Institute for Medical and Biological Engineering.

Ko is an assistant professor in the Department of Pathology and Laboratory Medicine in the Perelman School of Medicine and Department of Bioengineering in the School of Engineering and Applied Science. She focuses on developing single molecule detection from single extracellular vesicles and multiplexed molecular profiling to better diagnose diseases and monitor treatment efficacy. Ko earned her Ph.D. in bioengineering at Penn in 2018, during which time she developed machine learning-based microchip diagnostics that can detect blood-based biomarkers to diagnose pancreatic cancer and traumatic brain injury. For her postdoctoral training, she worked at the Massachusetts General Hospital and the Wyss Institute at Harvard University as a Schmidt Science Fellow and a NIH K99/R00 award recipient. Ko developed new methods to profile single cells and single extracellular vesicles with high throughput and multiplexing.

Read the full announcement in Penn Today.

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An Improved Delivery System for mRNA Vaccines Provides More Powerful Protection

by Devorah Fischler

(From left to right) Xuexiang Han, Michael Mitchell and Mohamad-Gabriel Alameh

The COVID-19 vaccine swiftly undercut the worst of the pandemic for hundreds of millions around the world. Available sooner than almost anyone expected, these vaccines were a triumph of resourcefulness and skill.

Messenger RNA vaccines, like the ones manufactured by Moderna or Pfizer/BioNTech, owed their speed and success to decades of research reinforcing the safety and effectiveness of their unique immune-instructive technology.

Now, researchers from the University of Pennsylvania School of Engineering and Applied Science and the Perelman School of Medicine are refining the COVID-19 vaccine, creating an innovative delivery system for even more robust protection against the virus.

In addition to outlining a more flexible and effective COVID-19 vaccine, this work has potential to increase the scope of mRNA vaccines writ large, contributing to prevention and treatment for a range of different illnesses.

Michael Mitchell, associate professor in Penn Engineering’s Department of Bioengineering, Xuexiang Han, postdoctoral fellow in Mitchell’s lab, and Mohamad-Gabriel Alameh, postdoctoral fellow in Drew Weissman’s lab at Penn Medicine and incoming assistant professor in the Department of Pathology and Laboratory Medicine at the Perelman School of Medicine, recently published their findings in Nature Nanotechnology.

mRNA, or messenger ribonucleic acid, is the body’s natural go-between. mRNA contains the instructions our cells need to produce proteins that play important roles in our bodies’ health, including mounting immune responses.

The COVID-19 vaccines follow suit, sending a single strand of RNA to teach our cells how to recognize and fight the virus.

Read the full story in Penn Engineering Today.

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2023 Graduate Research Fellowships for Bioengineering Students

Congratulations to the fourteen Bioengineering students to receive 2023  National Science Foundation Graduate Research Fellowship Program (NSF GRFP) fellowships. The prestigious NSF GRFP program recognizes and supports outstanding graduate students in NSF-supported fields. The recipients honorees were selected from a highly-competitive, nationwide pool. Further information about the program can be found on the NSF website.

Carlos Armando Aguila, Ph.D. student in Bioengineering, is a member of the Center of Neuroengineering and Therapeutics, advised by Erin Conrad, Assistant Professor in Neurology, and Brian Litt, Professor in Bioengineering and Neurology. His research focuses on analyzing electroencephalogram (EEG) signals to better understand epilepsy.

Joseph Lance Victoria Casila is a Ph.D. student in Bioengineering in the lab of Riccardo Gottardi, Assistant Professor in Pediatrics and Bioengineering. His research focuses on probing environmental factors that influence stem cell differentiation towards chondrogenesis for cartilage engineering and regeneration.

Trevor Chan is a Ph.D. student in Bioengineering in the lab of Felix Wehrli, Professor of Radiologic Science. His research is in developing computational methods for medical image refinement and analysis. Two ongoing projects are: self-supervised methods for CT super-resolution and assessment of osteoporosis, and semi-supervised segmentation of 3D and 4D echocardiograms for surgical correction of congenital heart-valve defects.

Rakan El-Mayta is an incoming Ph.D. student in the lab of Drew Weissman, Roberts Family Professor in Vaccine Research. Rakan studies messenger RNA-lipid nanoparticle vaccines for the treatment and prevention of infectious diseases. Prior to starting in the Bioengineering graduate program, he worked as a Research Assistant in Weissman lab and in the lab of Michael Mitchell, Associate Professor in Bioengineering.

Austin Jenk is a Ph.D. student in the lab of Robert Mauck, Mary Black Ralston Professor in Orthopaedic Surgery and Bioengineering. Austin aims to develop early intervention, intra-articular therapeutics to combat the onset of post-traumatic osteoarthritis following acute joint injuries. His work focuses on developing a therapeutic that can be employed not only in conventional healthcare settings, but also emergency and battlefield medicine.

Jiageng Liu is a Ph.D. student in the lab of Alex Hughes, Assistant Professor in Bioengineering. His work aims to precisely control the bio-physical/chemical properties of iPSC-derived organoids with advanced synthetic biology approaches to create functional replacement renal tissues.

Alexandra Neeser is a Ph.D. student in the lab of Leyuan Ma, Assistant Professor of Pathology and Laboratory Medicine. Her research focuses on solid tumor microenvironment delivery of therapeutics.

 

William Karl Selboe Ojemann, a Ph.D. Student in Bioengineering, is a member of the Center for Neuroengineering and Therapeutics directed by Brian Litt, Professor in Bioengineering and Neurology. His research is focused on developing improved neurostimulation therapies for epilepsy and other neurological disorders.

Savan Patel (BSE Class of 2023) conducted research in the lab of Michael Mitchell, Associate Professor in Bioengineering, where he worked to develop lipid nanoparticle formulations for immunotherapy and extrahepatic delivery of mRNA. He will be joining the Harvard-MIT HST MEMP Ph.D. program in the fall of 2023.

David E. Reynolds, a Ph.D. student in Bioengineering, is a member of the lab of Jina Ko, Assistant Professor in Bioengineering and Pathology and Laboratory Medicine. His research focuses on developing novel and translatable technologies to address currently intractable diagnostic challenges for precision medicine.

Andre Roots is a Ph.D. student in the lab of Christopher Madl, Assistant Professor in Materials Science and Engineering. His research focuses on the use of protein engineering techniques and an optimized 3D human skeletal muscle microtissue platform to study the effects of biophysical material properties on cells.

Emily Sharp, a second year Ph.D. student in Bioengineering, is a member of the lab of Robert Mauck, Mary Black Ralston Professor in Orthopaedic Surgery and Bioengineering, part of the McKay Orthopaedic Research Laboratories. Her research focuses on designing multi-functional biomaterials to enhance tissue repair, specifically intervertebral disc repair following herniation and discectomy.

Nat Thurlow is a Ph.D. student in the lab of Louis J. Soslowsky, Fairhill Professor in Orthopedic Surgery and Bioengineering. Their current work focuses on delineating the roles of collagens V and XI in tendon mechanics, fibril structure, and gene expression during tendon development and healing.

Maggie Wagner, Ph.D. student in Bioengineering, is a member in the labs of Josh Baxter, Assistant Professor of Orthopaedic Surgery, and Flavia Vitale, Assistant Professor in Neurology and Bioengineering. Her research focuses on the development of novel sensors to record and monitor muscle neuromechanics.

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Penn Bioengineering Graduate Student on T Cell Therapy Improvements

Image: Courtesy of Penn Medicine News

 Neil Sheppard,  Adjunct Associate Professor of Pathology and Laboratory Medicine in the Perelman School of Medicine, and David Mai, a Bioengineering graduate student in the School of Engineering and Applied Science, explained the findings of their recent study, which offered a potential strategy to improve T cell therapy in solid tumors, to the European biotech news website Labiotech.

Mai is a graduate student in the lab of Carl H. June, the Richard W. Vague Professor in Immunotherapy in Penn Medicine, Director of the Center for Cellular Immunotherapies (CCI) at the Abramson Cancer Center, and member of the Penn Bioengineering Graduate Group.

Read “Immunotherapy in the fight against solid tumors” in Labiotech.

Read more about this collaborative study here.

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Carl H. June, MD, FAACR, Honored with 2023 AACR Award for Lifetime Achievement in Cancer Research

Carl June, MD

 The American Association for Cancer Research (AACR), the largest cancer research organization in the country and based in Philadelphia, will bestow its 2023 Award for Lifetime Achievement in Cancer Research to Carl June, Richard W. Vague Professor in Immunotherapy in the Department of Pathology and Laboratory Medicine at Penn Medicine. June is also Director of the Center for Cellular Immunotherapies, Director of the Parker Institute for Cancer Immunotherapy, and member of the Penn Bioengineering Graduate Group. He is recognized for his groundbreaking work in developing the first gene-editing cell therapy for cancer and for his pioneering work with CAR T cell therapy.

Read the press release on the AACR website.

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ASSET Center Inaugural Seed Grants Will Fund Trustworthy AI Research in Healthcare

by Devorah Fischler

Illustration credit: Melissa Pappas

Penn Engineering’s newly established ASSET Center aims to make AI-enabled systems more “safe, explainable and trustworthy” by studying the fundamentals of the artificial neural networks that organize and interpret data to solve problems.

ASSET’s first funding collaboration is with Penn’s Perelman School of Medicine (PSOM) and the Penn Institute for Biomedical Informatics (IBI). Together, they have launched a series of seed grants that will fund research at the intersection of AI and healthcare.

Teams featuring faculty members from Penn Engineering, Penn Medicine and the Wharton School applied for these grants, to be funded annually at $100,000. A committee consisting of faculty from both Penn Engineering and PSOM evaluated 18 applications and  judged the proposals based on clinical relevance, AI foundations and potential for impact.

Artificial intelligence and machine learning promise to revolutionize nearly every field, sifting through massive amounts of data to find insights that humans would miss, making faster and more accurate decisions and predictions as a result.

Applying those insights to healthcare could yield life-saving benefits. For example, AI-enabled systems could analyze medical imaging for hard-to-spot tumors, collate multiple streams of disparate patient information for faster diagnoses or more accurately predict the course of disease.

Given the stakes, however, understanding exactly how these technologies arrive at their conclusions is critical. Doctors, nurses and other healthcare providers won’t use such technologies if they don’t trust that their internal logic is sound.

“We are developing techniques that will allow AI-based decision systems to provide both quantifiable guarantees and explanations of their predictions,” says Rajeev Alur, Zisman Family Professor in Computer and Information Science and Director of the ASSET Center. “Transparency and accuracy are key.”

“Development of explainable and trustworthy AI is critical for adoption in the practice of medicine,” adds Marylyn Ritchie, Professor of Genetics and Director of the Penn Institute for Biomedical Informatics. “We are thrilled about this partnership between ASSET and IBI to fund these innovative and exciting projects.”

 Seven projects were selected in the inaugural class, including projects from Dani S. Bassett, J. Peter Skirkanich Professor in the Departments of Bioengineering, Electrical and Systems Engineering, Physics & Astronomy, Neurology, and Psychiatry, and several members of the Penn Bioengineering Graduate Group: Despina Kontos, Matthew J. Wilson Professor of Research Radiology II, Department of Radiology, Penn Medicine and Lyle Ungar, Professor, Department of Computer and Information Science, Penn Engineering; Spyridon Bakas, Assistant Professor, Departments of Pathology and Laboratory Medicine and Radiology, Penn Medicine; and Walter R. Witschey, Associate Professor, Department of Radiology, Penn Medicine.

Optimizing clinical monitoring for delivery room resuscitation using novel interpretable AI

Elizabeth Foglia, Associate Professor, Department of Pediatrics, Penn Medicine and the Children’s Hospital of Philadelphia

Dani S. Bassett, J. Peter Skirkanich Professor, Departments of Bioengineering and Electrical and Systems Engineering, Penn Engineering

 This project will apply a novel interpretable machine learning approach, known as the Distributed Information Bottleneck, to solve pressing problems in identifying and displaying critical information during time-sensitive clinical encounters. This project will develop a framework for the optimal integration of information from multiple physiologic measures that are continuously monitored during delivery room resuscitation. The team’s immediate goal is to detect and display key target respiratory parameters during delivery room resuscitation to prevent acute and chronic lung injury for preterm infants. Because this approach is generalizable to any setting in which complex relations between information-rich variables are predictive of health outcomes, the project will lay the groundwork for future applications to other clinical scenarios.

Read the full list of projects and abstracts in Penn Engineering Today.

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CAR T Cell Therapy Reaches Beyond Cancer

Penn Medicine researchers laud the early results for CAR T therapy in lupus patients, which point to broader horizons for the use of personalized cellular therapies.

Penn Medicine’s Carl June and Daniel Baker.

Engineered immune cells, known as CAR T cells, have shown the world what personalized immunotherapies can do to fight blood cancers. Now, investigators have reported highly promising early results for CAR T therapy in a small set of patients with the autoimmune disease lupus. Penn Medicine CAR T pioneer Carl June and Daniel Baker, a doctoral student in cell and molecular biology in the Perelman School of Medicine, discuss this development in a commentary published in Cell.

“We’ve always known that in principle, CAR T therapies could have broad applications, and it’s very encouraging to see early evidence that this promise is now being realized,” says June, who is the Richard W. Vague Professor in Immunotherapy in the department of Pathology and Laboratory Medicine at Penn Medicine and director of the Center for Cellular Immunotherapies at the Abramson Cancer Center.

T cells are among the immune system’s most powerful weapons. They can bind to, and kill, other cells they recognize as valid targets, including virus-infected cells. CAR T cells are T cells that have been redirected, through genetic engineering, to efficiently kill specifically defined cell types.

CAR T therapies are created out of each patient’s own cells—collected from the patient’s blood, and then engineered and multiplied in the lab before being reinfused into the patient as a “living drug.” The first CAR T therapy, Kymriah, was developed by June and his team at Penn Medicine, and received Food & Drug Administration approval in 2017. There are now six FDA-approved CAR T cell therapies in the United States, for six different cancers.

From the start of CAR T research, experts believed that T cells could be engineered to fight many conditions other than B cell cancers. Dozens of research teams around the world, including teams at Penn Medicine and biotech spinoffs who are working to develop effective treatments from Penn-developed personalized cellular therapy constructs, are examining these potential new applications. Researchers say lupus is an obvious choice for CAR T therapy because it too is driven by B cells, and thus experimental CAR T therapies against it can employ existing anti-B-cell designs. B cells are the immune system’s antibody-producing cells, and, in lupus, B cells arise that attack the patient’s own organs and tissues.

This story is by Meagan Raeke. Read more at Penn Medicine News.

Carl June is a member of the Penn Bioengineering Graduate Group. Read more stories featuring June’s research here.

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The Penn Center for Precision Engineering for Health Announces First Round of Seed Funding

by Melissa Pappas

CPE4H is one of the focal points of Penn Engineering signature initiative on Engineering Health.

The Penn Center for Precision Engineering for Health (CPE4H) was established late last year to accelerate engineering solutions to significant problems in healthcare. The center is one of the signature initiatives for Penn’s School of Engineering and Applied Science and is supported by a $100 million commitment to hire faculty and support new research on innovative approaches to those problems.

Acting on that commitment, CPE4H solicited proposals during the spring of 2022 for seed grants of $80K per year for two years for research projects that address healthcare challenges in several key areas of strategic importance to Penn: synthetic biology and tissue engineering, diagnosis and drug delivery, and the development of innovative devices. While the primary investigators (PIs) for the proposed projects were required to have a primary faculty appointment within Penn Engineering, teams involving co-PIs and collaborators from other schools were eligible for support. The seed program is expected to continue for the next four years.

“It was a delight to read so many novel and creative proposals,” says Daniel A. Hammer, Alfred G. and Meta A. Ennis Professor in Bioengineering and the Inaugural Director of CPE4H. “It was very hard to make the final selection from a pool of such promising projects.”

Judged on technical innovation, potential to attract future resources, and ability to address a significant medical problem, the following research projects were selected to receive funding.

Evolving and Engineering Thermal Control of Mammalian Cells

Led by Lukasz Bugaj, Assistant Professor in Bioengineering, this project will engineer molecular switches that can be toggled on and off inside mammalian cells at near-physiological temperatures. Successful development of these switches will provide new ways to communicate with cells, an advance that could be used to make safer and more effective cellular therapies.  The project will use directed evolution to generate and find candidate molecular tools with the desired properties. Separately, the research will also develop new technology for manipulating cellular temperature in a rapid and programmable way. Such devices will enhance the speed and sophistication of studies of biological temperature regulation.

A Quantum Sensing Platform for Rapid and Accurate Point-of-Care Detection of Respiratory Viral Infections

Combining microfluidics and quantum photonics, PI Liang Feng, Professor in Materials Science and Engineering and Electrical and Systems Engineering, Ritesh Agarwal, Professor in Materials Science Engineering, and Shu Yang, Joseph Bordogna Professor in Materials Science and Engineering and Chemical and Biomolecular Engineering, are teaming up with Ping Wang, Professor of Pathology and Laboratory Medicine in Penn’s Perelman School of Medicine, to design, build and test an ultrasensitive point-of-care detector for respiratory pathogens. In light of the COVID-19 pandemic, a generalizable platform for rapid and accurate detection of viral pathogenesis would be extremely important and timely.

Versatile Coacervating Peptides as Carriers and Synthetic Organelles for Cell Engineering

PI Amish Patel, Associate Professor in Chemical and Biomolecular Engineering, and Matthew C. Good, Associate Professor of Cell and Developmental Biology in the Perelman School of Medicine and in Bioengineering, will design and create small proteins that self-assemble into droplet-like structures known as coacervates, which can then pass through the membranes of biological cells. Upon cellular entry, these protein coacervates can disassemble to deliver cargo that modulates cell behavior or be maintained as synthetic membraneless organelles. The team will design new chemistries that will facilitate passage across cell membranes, and molecular switches to sequester and release protein therapeutics. If successful, this approach could be used to deliver a wide range of macromolecule drugs to cells.

Towards an Artificial Muscle Replacement for Facial Reanimation

Cynthia Sung, Gabel Family Term Assistant Professor in Mechanical Engineering and Applied Mechanics and Computer Information Science, will lead a research team including Flavia Vitale, Assistant Professor of Neurology and Bioengineering, and Niv Milbar, Assistant Instructor in Surgery in the Perelman School of Medicine. The team will develop and validate an electrically driven actuator to restore basic muscle responses in patients with partial facial paralysis, which can occur after a stroke or injury. The research will combine elements of robotics and biology, and aims to produce a device that can be clinically tested.

“These novel ideas are a great way to kick off the activities of the center,” says Hammer. “We look forward to soliciting other exciting seed proposals over the next several years.”

This article originally appeared in Penn Engineering Today.

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Researchers Develop Technology to Keep Track of Living Cells and Tissues

SAFE Bioorthogonal Cycling

Cells in complex organisms undergo frequent changes, and researchers have struggled to monitor these changes and create a comprehensive profile for living cells and tissues. Historically researchers have been limited to only 3-5 markers due to spectral overlaps in fluorescence microscopy, an essential tool required for imaging cells. With only this small handful of markers, it is difficult to monitor protein expressions of live cells and a comprehensive profile of cellular dynamics cannot be created. However, a new study in Nature Biotechnology addresses these limitations by demonstrating a new method for comprehensive profiling of living cells.

Jina Ko, PhD

Jina Ko, Assistant Professor in Bioengineering in the School of Engineering and Applied Science and in Pathology and Laboratory Medicine in the Perelman School of Medicine, conducted postdoctoral research at Massachusetts General Hospital (MGH) and the Wyss Institute at Harvard University, and the work for this study was done under the supervision of Jonathan Carlson M.D., Ph.D. and Ralph Weissleder M.D., Ph.D. of MGH. Ko’s lab at Penn develops novel technologies using bioengineering, molecular biology, and chemistry to address diagnostic challenges for precision medicine.

To address these limitations in microscopy, the team developed a new chemistry tool which was highly gentle to cells. This “scission-accelerated fluorophore exchange (or SAFE)” method utilizes “click” chemistry, a type of chemistry that follows examples found in nature to create fast and simple reactions. This new SAFE method functions with non-toxic conditions to living cells and tissues, whereas previous methods have used harsh chemicals that would strip off fluorophores and consequently would not work with living cells and tissues.

With the development of SAFE, the authors demonstrated that researchers can now effectively perform multiple cycles of cell profiling and can monitor cellular changes over the course of their observations. Instead of the previous limitation of 3-5 markers total, SAFE allows for many more cycles and can keep track of almost as many markers as the researcher wants. One can now stain cells and quench/release fluorophores and repeat the cycle multiple times for multiplexing on living cells. Each cycle can profile 3 markers, and so someone interested in profiling 15 markers could easily perform 5 cycles to achieve this much more comprehensive cell profile. With this breakthrough in more detailed imaging of cells, SAFE demonstrates broad applicability for allowing researchers to better investigate the physiologic dynamics in living systems.

Read the paper, “Spatiotemporal multiplexed immunofluorescence imaging of living cells and tissues with bioorthogonal cycling of fluorescent probes,” in Nature Biotechnology.

This study was supported by the Schmidt Science Fellows in Partnership with the Rhodes Trust and National Institutes of Health, National Cancer Institute (K99CA256353).