Tag: postdoc

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A New Way to Profile T Cells Can Aid in Personalized Immunotherapy

by Melissa Pappas

A scanning electron micrograph of a healthy human T cell. A better understanding the wide variety of antigen receptors that appear on the surfaces of these critical components of the immune system is necessary for improving a new class of therapies. (Credit: NIAID)

Our bodies are equipped with specialized white blood cells that protect us from foreign invaders, such as viruses and bacteria. These T cells identify threats using antigen receptors, proteins expressed on the surface of individual T cells that recognize specific amino acid sequences found in or on those invaders. Once a T cell’s antigen receptors bind to the corresponding antigen, it can directly kill infected cells or call for backup from the rest of the immune system.

We have hundreds of billions of T cells, each with unique receptors that recognize unique antigens, so profiling this T cell antigen specificity is essential in our understanding of the immune response. It is especially critical in developing targeted immunotherapies, which equip T cells with custom antigen receptors that recognize threats they would otherwise miss, such as the body’s own mutated cancer cells.

Jenny Jiang, Ph.D.

Jenny Jiang, Peter and Geri Skirkanich Associate Professor of Innovation in Bioengineering, along with lab members and colleagues at the University of Texas, Austin, recently published a study in Nature Immunology that describes their technology, which simultaneously provides information in four dimensions of T cell profiling. Ke-Yue Ma and Yu-Wan Guo, a former post doc and current graduate student in Jiang’s Penn Engineering lab, respectively, also contributed to this study.

This technology, called TetTCR-SeqHD, is the first to provide such detailed information about single T cells in a high-throughput manner, opening doors for personalized immune diagnostics and immunotherapy development.

There are many pieces of information needed to comprehensively understand the immune response of T cells, and gathering all of these measurements simultaneously has been a challenge in the field. Comprehensive profiling of T cells includes sequencing the antigen receptors, understanding how specific those receptors are in their recognition of invading antigens, and understanding T cell gene and protein expression. Current technologies only screen for one or two of these dimensions due to various constraints.

“Current technologies that measure T cell immune response all have limitations,” says Jiang. “Those that use cultured or engineered T cells cannot tell us about their original phenotype, because once you take a cell out of the body to culture, its gene and protein expression will change. The technologies that address T cell and antigen sequencing with mass spectrometry damage genetic information of the sample. And current technologies that do provide information on antigen specificity use a very expensive binding ligand that can cost more than a thousand dollars per antigen, so it is not feasible if we want to look at hundreds of antigens. There is clearly room for advancement here.”

The TetTCR-SeqHD technology combines Jiang’s previously developed T cell receptor sequencing tool, TetTCR-Seq, described in a Nature Biotechnology paper published in 2018, with the new ability of characterizing both gene and protein expression.

Read the full story in Penn Engineering Today.

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César de La Fuente Uses AI to Discover Germ-fighting Peptides

César de la Fuente, PhD

The impending danger of bacterial resistance to antibiotics is well-documented within the scientific community. Bacteria are the most efficient evolvers, and their ability to develop tolerance to drugs, in addition to antibiotic overuse and misuse, means that researchers have had to get particularly resourceful to ensure the future of modern medicine.  

Presidential Assistant Professor in Bioengineering, Microbiology, Psychiatry, and Chemical and Biomolecular Engineering César de la Fuente and his team are using an algorithm to search the human genome for microbe-fighting peptides. So far, the team has synthesized roughly 55 peptides that, when tested against popular drug-resistant microbes such as the germ responsible for staph infections, have proven to prevent bacteria from replicating.  

WIRED’s Max G. Levy recently spoke with de la Fuente and postdoctoral researcher and study collaborator Marcelo Torres about the urgency of the team’s work, and why developing these solutions is critical to the survival of civilization as we know it. The team’s algorithm, based on pattern recognition software used to analyze images, makes an otherwise insurmountable feat tangible.  

De la Fuente’s lab specializes in using AI to discover and design new drugs. Rather than making some all-new peptide molecules that fit the bill, they hypothesized that an algorithm could use machine learning to winnow down the huge repository of natural peptide sequences in the human proteome into a select few candidates.

“We know those patterns—the multiple patterns—that we’re looking for,” says de la Fuente. “So that allows us to use the algorithm as a search function.”

Read Max G. Levy’s “An AI Finds Superbug-Killing Potential in Human Proteins” at WIRED. 

This story previously appeared in Penn Engineering Today.

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Yogesh Goyal Selected as 2021 STAT Wunderkind

Yogesh Goyal, Ph.D.

Yogesh Goyal, Ph.D.,  a postdoctoral researcher in Genetics and Bioengineering, has been selected as a 2021 STAT Wunderkind, which honors the “next generation of scientific superstars.” Goyal’s research is centered around developing novel mathematical and experimental frameworks to study how a rare subpopulation of cancer cells are able to survive drug therapy and develop resistance, resulting in relapse in patients. In particular, his work provides a view of different paths that single cancer cells take when becoming resistant, at unprecedented resolution and scale. This research aims to help devise novel therapeutic strategies to combat the challenge of drug resistance in cancer.

Goyal is a Jane Coffin Childs Postdoctoral Fellow in the systems biology lab of Arjun Raj, Professor in Bioengineering and Genetics at Penn. He will begin an appointment as Assistant Professor in the Department of Cell and Developmental Biology (CDB) in the Feinberg School of Medicine at Northwestern University in spring 2022.

Read the announcement in Penn Medicine News.

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Penn Researchers Show ‘Encrypted’ Peptides Could be Wellspring of Natural Antibiotics

by Melissa Pappas

César de la Fuente, Ph.D.

While biologists and chemists race to develop new antibiotics to combat constantly mutating bacteria, predicted to lead to 10 million deaths by 2050, engineers are approaching the problem through a different lens: finding naturally occurring antibiotics in the human genome.

The billions of base pairs in the genome are essentially one long string of code that contains the instructions for making all of the molecules the body needs. The most basic of these molecules are amino acids, the building blocks for peptides, which in turn combine to form proteins. However, there is still much to learn about how — and where — a particular set of instructions are encoded.

Now, bringing a computer science approach to a life science problem, an interdisciplinary team of Penn researchers have used a carefully designed algorithm to discover a new suite of antimicrobial peptides, hiding deep within this code.

The study, published in Nature Biomedical Engineering, was led by César de la Fuente, Presidential Assistant Professor in Bioengineering, Microbiology, Psychiatry, and Chemical and Biomolecular Engineering, spanning both Penn Engineering and Penn Medicine, and his postdocs Marcelo Torres and Marcelo Melo. Collaborators Orlando Crescenzi and Eugenio Notomista of the University of Naples Federico II also contributed to this work.

“The human body is a treasure trove of information, a biological dataset. By using the right tools, we can mine for answers to some of the most challenging questions,” says de la Fuente. “We use the word ‘encrypted’ to describe the antimicrobial peptides we found because they are hidden within larger proteins that seem to have no connection to the immune system, the area where we expect to find this function.”

Read the full story in Penn Engineering Today.

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BE Seminar: “Phage and Robotics-Assisted Biomolecular Evolution” (Emma Chory)

Emma Chory, Ph.D.

Speaker: Emma Chory, Ph.D.
Postdoctoral Fellow
Sculpting Evolution Laboratory
Massachusetts Institute of Technology

Date: Thursday, October 21, 2021
Time: 3:30-4:30 PM EDT
Zoom – check email for link or contact ksas@seas.upenn.edu
Room: Moore 216

Abstract: Evolution occurs when selective pressures from the environment shape inherited variation over time. Within the laboratory, evolution is commonly used to engineer proteins and RNA, but experimental constraints have limited our ability to reproducibly and reliably explore key factors such as population diversity, the timing of environmental changes, and chance. We developed a high-throughput system for the analytical exploration of molecular evolution using phage-based mutagenesis to evolve many distinct classes of biomolecules simultaneously. In this talk, I will describe the development of our open-source python:robot integration platform which enables us to adjust the stringency of selection in response to real-time evolving activity measurements and to dissect the historical, environmental, and random factors governing biomolecular evolution. Finally, I will talk about our many on-going projects which utilize this system to evolve previously intractable biomolecules using novel small-molecule substrates to target the undruggable proteome.

Emma Chory Bio: Emma Chory is a postdoctoral fellow in the Sculpting Evolution Group at MIT, advised by Kevin Esvelt and Jim Collins. Emma’s research utilizes directed evolution, robotics, and chemical biology to evolve biosynthetic pathways for the synthesis of novel peptide-based therapeutics. Emma obtained her PhD in Chemical Engineering in the laboratory of Gerald Crabtree at Stanford University. She is the recipient of the NSF Graduate Research Fellowship and a pre- and postdoctoral NIH NRSA Fellowship.

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Atomically-thin, Twisted Graphene Has Unique Properties

by Erica K. Brockmeier

New collaborative research describes how electrons move through two different configurations of bilayer graphene, the atomically-thin form of carbon. These results provide insights that researchers could use to design more powerful and secure quantum computing platforms in the future.

New research published in Physical Review Letters describes how electrons move through two different configurations of bilayer graphene, the atomically-thin form of carbon. This study, the result of a collaboration between Brookhaven National Laboratory, the University of Pennsylvania, the University of New Hampshire, Stony Brook University, and Columbia University, provides insights that researchers could use to design more powerful and secure quantum computing platforms in the future.

“Today’s computer chips are based on our knowledge of how electrons move in semiconductors, specifically silicon,” says first and co-corresponding author Zhongwei Dai, a postdoc at Brookhaven. “But the physical properties of silicon are reaching a physical limit in terms of how small transistors can be made and how many can fit on a chip. If we can understand how electrons move at the small scale of a few nanometers in the reduced dimensions of 2-D materials, we may be able to unlock another way to utilize electrons for quantum information science.”

When a material is designed at these small scales, to the size of a few nanometers, it confines the electrons to a space with dimensions that are the same as its own wavelength, causing the material’s overall electronic and optical properties to change in a process called quantum confinement. In this study, the researchers used graphene to study these confinement effects in both electrons and photons, or particles of light.

The work relied upon two advances developed independently at Penn and Brookhaven. Researchers at Penn, including Zhaoli Gao, a former postdoc in the lab of Charlie Johnson who is now at The Chinese University of Hong Kong, used a unique gradient-alloy growth substrate to grow graphene with three different domain structures: single layer, Bernal stacked bilayer, and twisted bilayer. The graphene material was then transferred onto a special substrate developed at Brookhaven that allowed the researchers to probe both electronic and optical resonances of the system.

“This is a very nice piece of collaborative work,” says Johnson. “It brings together exceptional capabilities from Brookhaven and Penn that allow us to make important measurements and discoveries that none of us could do on our own.”

Read the full story in Penn Today.

Charlie Johnson is the Rebecca W. Bushnell Professor of Physics and Astronomy in the Department of Physics and Astronomy in the School of Arts & Sciences at the University of Pennsylvania and a member of the Penn Bioengineering Graduate Group.

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Reimagining Scientific Discovery Through the Lens of an Artist

by Erica K. Brockmeier

Rebecca Kamen, Penn artist-in-residence and visiting scholar, has a new exhibition titled “Reveal: The Art of Reimagining Scientific Discovery” at American University Museum at the Katzen Arts Center that explores curiosity and the creative process across art and science. (Image: Greg Staley)

Rebecca Kamen, Penn artist-in-residence and visiting scholar, has long been interested in science and the natural world. As a Philadelphia native and an artist with a 40-plus-year career, her intersectional work sheds light on the process of scientific discovery and its connections to art, with previous exhibitions that celebrate Apollo 11’s “spirit of exploration and discovery” to new representations of the periodic table of elements.

Now, in her latest exhibition, Kamen has created a series of pieces that highlight how the creative processes in art and science are interconnected. In “Reveal: The Art of Reimagining Scientific Discovery,” Kamen chronicles her own artistic process while providing a space for self-reflection that enables viewers to see the relationship between science, art, and their own creativity.

The exhibit, on display at the Katzen Art Center at American University, was inspired by the work of Penn professor Dani Bassett and American University professor Perry Zurn, the exhibit’s faculty sponsor. The culmination of three years of work, “Reveal” features collaborations with a wide range of scientists, including philosophers at American University, microscopists at the National Institutes of Health studying SARS-CoV-2 , and researchers in Penn’s Complex Systems Lab and the Addiction, Health, and Adolescence (AHA!) Lab.

Continue reading at Penn Today.

Dani S. Bassett is the J. Peter Skirkanich Professor in the departments of Bioengineering and Electrical and Systems Engineering in the School of Engineering and Applied Science at the University of Pennsylvania. She also has appointments in the Department of Physics and Astronomy in Penn’s School of Arts & Sciences and the departments of Neurology and Psychiatry in the Perelman School of Medicine at Penn.

Rebecca Kamen is a visiting scholar and artist-in-residence in the Department of Physics & Astronomy in Penn’s School of Arts & Sciences.

David Lydon-Staley is an assistant professor in the Annenberg School for Communication at Penn and was formerly a postdoc in the Bassett lab.

Dale Zhou is a Ph.D. candidate in Penn’s Neuroscience Graduate Group.

“Reveal: The Art of Reimagining Scientific Discovery,” presented by the Alper Initiative for Washington Art and curated by Sarah Tanguy, is on display at the American University Museum in Washington, D.C., until Dec. 12.

The exhbition catalog, which includes an essay on “Radicle Curiosity” by Perry Zurn and Dani S. Bassett, can be viewed online.

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Yogesh Goyal Appointed Assistant Professor at Northwestern University

Yogesh Goyal, Ph.D.

The Department of Bioengineering is proud to congratulate Yogesh Goyal on his appointment as Assistant Professor in the Department of Cell and Developmental Biology (CDB) in the Feinberg School of Medicine at Northwestern University. His lab will be housed within the Center for Synthetic Biology. His appointment will begin in Spring 2022.

Yogesh grew up in Chopra Bazar, a small rural settlement in Jammu and Kashmir, India. He received his undergraduate degree in Chemical Engineering from the Indian Institute of Technology Gandhinagar. Yogesh joined Princeton University for his Ph.D. in Chemical and Biological Engineering, jointly mentored by Professors Stanislav Shvartsman and Gertrud Schüpbach. Yogesh is currently a Jane Coffin Childs Postdoctoral Fellow in the lab of Arjun Raj, Professor in Bioengineering and Genetics at Penn.

“I am so excited for Yogesh beginning his faculty career,” Raj says. “He is a wonderful scientist with a sense of aesthetics. His work is simultaneously significant and elegant, a powerful combination.”

With a unique background in engineering, developmental biology, biophysical modeling, and single-cell biology, Yogesh develops quantitative approaches to problems in developmental biology and cancer drug resistance. As a postdoc, Yogesh developed theoretical and experimental lineage tracing approaches to study how non-genetic fluctuations may arise within genetically identical cancer cells and how these fluctuations affect the outcomes upon exposure to targeted therapy drugs. The Goyal Lab at Northwestern will “combine novel experimental, computational, and theoretical frameworks to monitor, perturb, model, and ultimately control single-cell variabilities and emergent fate choices in development and disease, including cancer and developmental disorders.”

“I am excited to start a new chapter in my academic career at Northwestern University,” Goyal says. “I am grateful for my time at Penn Bioengineering, and I thank my mentor Arjun Raj and the rest of the lab members for making this time intellectually and personally stimulating.”

Congratulations to Dr. Goyal from everyone at Penn Bioengineering!

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Annenberg and Penn Bioengineering Research into Communication Citation Bias

Photo Credit: Debby Hudson / Unsplash

Women are frequently under-cited in academia, and the field of communication is no exception, according to research from the Annenberg School for Communication. The study, entitled “Gendered Citation Practices in the Field of Communication,” was published in Annals of the International Communication Association.

A new study from the Addiction, Health, & Adolescence (AHA!) Lab at the Annenberg School for Communication at the University of Pennsylvania found that men are over-cited and women are under-cited in the field of Communication. The researchers’ findings indicate that this problem is most persistent in papers authored by men.

“Despite known limitations in their use as proxies for research quality, we often turn to citations as a way to measure the impact of someone’s research,” says Professor David Lydon-Staley, “so it matters for individual researchers if one group is being consistently under-cited relative to another group. But it also matters for the field in the sense that if people are not citing women as much as men, then we’re building the field on the work of men and not the work of women. Our field should be representative of all of the excellent research that is being undertaken, and not just that of one group.”

The AHA! Lab is led by David Lydon-Staley, Assistant Professor of Communication and former postdoc in the Complex Systems lab of Danielle Bassett, J. Peter Skirkanich Professor in Bioengineering and in Electrical and Systems Engineering in the School of Engineering and Applied Science. Dr. Bassett and Bassett Lab members Dale Zhou and Jennifer Stiso, graduate students in the Perelman School of Medicine, also contributed to the study.

Read “Women are Under-cited and Men are Over-cited in Communication” in Annenberg School for Communication News.

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Penn Engineering’s Latest ‘Organ-On-a-Chip’ is a New Way to Study Cancer-related Muscle Wasting

by Melissa Pappas

Bioengineering’s Dan Huh and colleagues have developed a number of organ-on-a-chip devices to simulate how human cells grow and perform in their natural environments. Their latest is a muscle-on-a-chip, which carefully captures the directionality of muscle cells as they anchor themselves within the body. See the full infographic at the bottom of this story. (Illustration by Melissa Pappas).

Studying drug effects on human muscles just got easier thanks to a new “muscle-on-a-chip,” developed by a team of researchers from Penn’s School of Engineering and Applied Science and Inha University in Incheon, Korea.

Muscle tissue is essential to almost all of the body’s organs, however, diseases such as cancer and diabetes can cause muscle tissue degradation or “wasting,” severely decreasing organ function and quality of life. Traditional drug testing for treatment and prevention of muscle wasting is limited through animal studies, which do not capture the complexity of the human physiology, and human clinical trials, which are too time consuming to help current patients.

An “organ-on-a-chip” approach can solve these problems. By growing real human cells within microfabricated devices, an organ-on-a-chip provides a way for scientists to study replicas of human organs outside of the body.

Using their new muscle-on-a-chip, the researchers can safely run muscle injury experiments on human tissue, test targeted cancer drugs and supplements, and determine the best preventative treatment for muscle wasting.

organ-on-a-chip
Dan Huh, Ph.D.

This research was published in Science Advances and was led by Dan Huh, Associate Professor in the Department of Bioengineering, and Mark Mondrinos, then a postdoctoral researcher in Huh’s lab and currently an Assistant Professor of Biomedical Engineering at Tulane University. Their co-authors included Cassidy Blundell and Jeongyun Seo, former Ph.D. students in the Huh lab, Alex Yi and Matthew Osborn, then research technicians in the Huh lab, and Vivek Shenoy, Eduardo D. Glandt President’s Distinguished Professor in the Department of Materials Science and Engineering. Lab members Farid Alisafaei and Hossein Ahmadzadeh also contributed to the research. The team collaborated with Insu Lee and professors Sun Min Kim and Tae-Joon Jeon of Inha University.

In order to conduct meaningful drug testing with their devices, the research team needed to ensure that cultured structures within the muscle-on-a-chip were as close to the real human tissue as possible. Critically, they needed to capture muscle’s “anisotropic,” or directionally aligned, shape.

“In the human body, muscle cells adhere to specific anchor points due to their location next to ligament tissue, bones or other muscle tissue,” Huh says. “What’s interesting is that this physical constraint at the boundary of the tissue is what sculpts the shape of muscle. During embryonic development, muscle cells pull at these anchors and stretch in the spaces in between, similar to a tent being held up by its poles and anchored down by the stakes. As a result, the muscle tissue extends linearly and aligns between the anchoring points, acquiring its characteristic shape.”

The team mimicked this design using a microfabricated chip that enabled similar anchoring of human muscle cells, sculpting three-dimensional tissue constructs that resembled real human skeletal muscle.

The the full story in Penn Engineering Today.