‘Organ-on-a-Chip’ Device Provides New Insights into Early-Stage Pregnancy

by Scott Harris

Dan Huh’s BIOLines Lab develops several different kinds of organ-on-a-chip systems, such as this blinking-eye-on-a-chip.

If you’d read about it in a science fiction novel, you might not have believed it. Human organs and organ systems — from lungs to blood vessels to blinking eyes — bio-miniaturized and stored on a plastic chip no larger than a matchbook.

But that’s the breathing, blinking reality at the Biologically Inspired Engineering Systems (BIOLines) Laboratory in the Department of Bioengineering in the School of Engineering and Applied Sciences at the University of Pennsylvania, a bona fide pioneer of what is now widely known as “organ-on-a-chip” technology. Proponents hope these devices can one day help scientists around the world learn more about the body’s inner workings and ultimately improve disease prevention and treatment.

“The century-old practice of cell culture is to grow living cells isolated from the human body in hard plastic dishes and keep them bathed in copious amounts of culture media under static conditions, and that is drastically different than the complex, dynamic environment of native tissues in which these cell reside,” said Dan Dongeun Huh, Ph.D., BIOLines’ principal investigator and an associate professor of Bioengineering in Penn’s School of Engineering and Applied Science. “What makes this organ-on-a-chip technology so unique and powerful is that it enables us to reverse-engineer living human tissues using microengineered devices and mimic their intricate biological interactions and physiological functions in ways that have not been possible using traditional cell culture techniques. This represents a major advance in our ability to model and understand the inner workings of complex physiological systems in the human body.”

Generally speaking, organ-on-a-chip devices are made of clear silicone rubber — the same material used to make contact lenses — and can vary in size and design. Embedded within are microfabricated three-dimensional chambers lined with different human cell types, arranged and propagated to ultimately form a structure complex enough to actually mimic the essential elements of a functioning organ.

With partners at the Perelman School of Medicine, BIOLines recently developed a newer variation of the organ-on-a-chip: one that replicates the interface between maternal tissue and the cells of the placenta at the critical moments in early pregnancy when the embryo is implanting in the uterus. Huh and Penn Medicine physicians led a study using the “implantation-on-a-chip” to observe things that would otherwise have been virtually unobservable.

The study findings appeared this spring in the journal Nature Communications.

Continue reading at Penn Medicine News.

Listen: ‘Curious Minds’ on NPR’s ‘Detroit Today’

by Ebonee Johnson

Twin siblings and scholars Dani S. Bassett of Penn and Perry Zurn of American University collaborated over half a dozen years to write “Curious Minds: The Power of Connection.” (Image: Tony and Tracy Wood Photography)

Twin academics Dani S. Basset, J. Peter Skirkanich Professor and director of the Complex Systems Lab, and Perry Zurn, a professor of philosophy at American University, were recently featured as guests on NPR radio show “Detroit Today” to discuss their new book, “Curious Mind: The Power of Connection.”

In their book, Basset and Zurn draw on their previous research, as well as an expansive network of ideas from philosophy, history, education and art to explore how and why people experience curiosity, as well as the different types it can take.

Basset, who holds appointments in the Departments of Bioengineering and Electrical and Systems Engineering, as well as the Department of Physics and Astronomy in Penn Arts & Science, and the Departments of Neuroscience and Psychiatry in Penn Perelman’s School of Medicine, and Zurn spoke with “Detroit Today” producer Sam Corey about what types of things make people curious, and how to stimulate more curiosity in our everyday lives.

According to the twin experts, curiosity is not a standalone facet of one’s personality. Basset and Zurn’s work has shown that a person’s capacity for inquiry is very much tied to the overall state of their health.

“There’s a lot of scientific research focusing on intellectual humility and also openness to ideas,” says Bassett. “And there are really interesting relationships between someone’s openness to ideas, someone’s intellectual humility and their curiosity and also their wellbeing or flourishing,”

Listen to “What makes people curious and how to encourage the act” at “Detroit Today.”

Register for a book signing event for “Curious Minds: The Power of Connection,” on Friday, December 9th at the Penn Bookstore.

This story originally appeared in Penn Engineering Today.

Microbes That Cause Cavities Can Form Superorganisms Able to ‘Crawl’ and Spread On Teeth

by Katherine Unger Baillie

Hyun (Michel) Koo

A cross-kingdom partnership between bacteria and fungi can result in the two joining to form a “superorganism” with unusual strength and resilience. It may sound like the stuff of science fiction, but these microbial groupings are very much part of the here and now.

Found in the saliva of toddlers with severe childhood tooth decay, these assemblages can effectively colonize teeth. They were stickier, more resistant to antimicrobials, and more difficult to remove from teeth than either the bacteria or the fungi alone, according to the research team, led by University of Pennsylvania School of Dental Medicine scientists.

What’s more, the assemblages unexpectedly sprout “limbs” that propel them to “walk” and “leap” to quickly spread on the tooth surface, despite each microbe on its own being non-motile, the team reported in the journal Proceedings of the National Academy of Sciences

“This started with a very simple, almost accidental discovery, while looking at saliva samples from toddlers who develop aggressive tooth decay,” says Hyun (Michel) Koo, a professor at Penn Dental Medicine and a co-corresponding author on the paper. “Looking under the microscope, we noticed the bacteria and fungi forming these assemblages and developing motions we never thought they would possess: a ‘walking-like’ and ‘leaping-like’ mobility. They have a lot of what we call ‘emergent functions’ that bring new benefits to this assemblage that they could not achieve on their own. It’s almost like a new organism—a superorganism—with new functions.”

Read the full story in Penn Today.

Hyun (Michel) Koo is a professor in the Department of Orthodontics and the divisions of Community Oral Health and Pediatric Dentistry in the School of Dental Medicine, co-founder of the Center for Innovation & Precision Dentistry (CiPD) at the University of Pennsylvania, and member of the Penn Bioengineering Graduate Group.

Defining Neural “Representation”

by Marilyn Perkins

Neuroscientists frequently say that neural activity ‘represents’ certain phenomena, PIK Professor Konrad Kording and postdoc Ben Baker led a study that took a philosophical approach to tease out what the term means.

Monitors Show EEG Reading and Graphical Brain Model. In the Background Laboratory Man Wearing Brainwave Scanning Headset Sits in a Chair with Closed Eyes. In the Modern Brain Study Research Laboratory
Neuroscientists use the word “represent” to encompass multifaceted relationships between brain activity, behavior, and the environment.

One of neuroscience’s greatest challenges is to bridge the gaps between the external environment, the brain’s internal electrical activity, and the abstract workings of behavior and cognition. Many neuroscientists rely on the word “representation” to connect these phenomena: A burst of neural activity in the visual cortex may represent the face of a friend or neurons in the brain’s memory centers may represent a childhood memory.

But with the many complex relationships between mind, brain, and environment, it’s not always clear what neuroscientists mean when they say neural activity “represents” something. Lack of clarity around this concept can lead to miscommunication, flawed conclusions, and unnecessary disagreements.

To tackle this issue, an interdisciplinary paper takes a philosophical approach to delineating the many aspects of the word “representation” in neuroscience. The work, published in Trends in Cognitive Sciences, comes from the lab of Konrad Kording, a Penn Integrates Knowledge University Professor and senior author on the study whose research lies at the intersection of neuroscience and machine learning.

“The term ‘representation’ is probably one of the most common words in all of neuroscience,” says Kording, who has appointments in the Perelman School of Medicine and School of Engineering and Applied Science. “But it might mean something very different from one professor to another.”

Read the full story in Penn Today.

Konrad Kording is a Penn Integrates Knowledge University Professor with joint appointments in the Department of Neuroscience the Perelman School of Medicine and in the Department of Bioengineering in the School of Engineering and Applied Science.

Ben Baker is a postdoctoral researcher in the Kording lab and a Provost Postdoctoral Fellow. Baker received his Ph.D. in philosophy from Penn.

Also coauthor on the paper is Benjamin Lansdell, a data scientist in the Department of Developmental Neurobiology at St. Jude Children’s Hospital and former postdoctoral researcher in the Kording lab.

Funding for this study came from the National Institutes of Health (awards 1-R01-EB028162-01 and R01EY021579) and the University of Pennsylvania Office of the Vice Provost for Research.

CEMB Researchers Find that Disease Can Change the Physical Structure of Cells

by Ebonee Johnson

In these super-resolution images of tendon cell nuclei, the color coding represents chromatin density map, from low density in blue to high density in red. Comparing a healthy human tendon cell nucleus (left) to one diagnosed with tendinosis (right) shows that disease alters the spatial localization and compaction of chromatin.

Researchers from Penn’s Center for Engineering Mechanobiology (CEMB) have discovered that cells change the physical structure of their genome when they’re affected by disease.

In a recent study published in Nature Biomedical Engineering, the team detailed what they found when they closely observed the nucleus of cells inside connective tissues deteriorating as a result of tendinosis, which is the chronic condition that results from a tendon repeatedly suffering small injuries that don’t heal correctly. Using the latest super-resolution imaging techniques, they found that the tendon cells involved in maintaining the tissue’s structure in a diseased microenvironment improperly reorder their chromatin — the DNA-containing material that chromosomes are composed of — when attempting to repair.

This and other findings highlighted in the report point to the possibility of new treatments, such as small-molecule therapies, that could restore order to the affected cells.

“Interestingly, we were able to explain the role of mechanical forces on the 3-D organization of chromatin by developing a theory that integrates fundamental thermodynamic principles (physics) with the kinetics of epigenetic regulation (biology),” said study co-author and CEMB Director Vivek Shenoy in a news release from Penn Medicine News.

The CEMB, one of 18 active interdisciplinary research centers funded by the National Science Foundation’s Science and Technology Center (STC) program, brings together dozens of researchers from Penn Engineering and the Perelman School of Medicine, as well as others spread across campus and at partner institutions around the world.

With its funding recently renewed for another five years, the CEMB has entered  into a new phase of its mission, centered on the nascent concept of “mechanointelligence,” which is exemplified by studies like this one. While mechanobiology is the study of the physical forces that govern the behavior of cells and their communication with their neighbors, mechanointelligence adds another layer of complexity: attempting to understand the forces that allow cells to sense, remember and adapt to their environments.

Ultimately, harnessing these forces would allow researchers to help multicellular organisms — plants, animals and humans — better adapt to their environments as well.

Read “Aberrant chromatin reorganization in cells from diseased fibrous connective tissue in response to altered chemomechanical cues” at Nature Biomedical Engineering.

Read “The Locked Library: Disease Causes Cells to Reorder Their DNA Incorrectly” at Penn Medicine News.

This story originally appeared in Penn Engineering Today.

Vivek Shenoy is Eduardo D. Glandt President’s Distinguished Professor in Materials Science and Engineering, Bioengineering, and in Mechanical Engineering and Applied Mechanics.

‘Curious Minds: The Power of Connection’

Twin siblings and scholars Dani S. Bassett of Penn and Perry Zurn of American University collaborated over half a dozen years to write “Curious Minds: The Power of Connection.” (Image: Tony and Tracy Wood Photography)

With appointments in the Departments of Bioengineering and Electrical and Systems Engineering, as well as the Department of Physics and Astronomy in Penn Arts & Science, and the Departments of Neuroscience and Psychiatry in Penn Perelman’s School of Medicine, Dani S. Bassett is no stranger to following the thread of an idea, no matter where it might lead.

Curious Minds book cover

Those wide-ranging fields and disciplines orbit around an appropriate central question: how does the tangle of neurons in our brains wire itself up to learn new things? Bassett, J. Peter Skirkanich Professor and director of the Complex Systems Lab, studies the relationship between the shape of those networks of neurons and the brain’s abilities, especially the way the shape of the network grows and changes with the addition of new knowledge.

 

To get at the fundamentals of the question of curiosity, Bassett needed to draw on even more disciplines. Fortunately, they didn’t have to look far; Bassett’s identical twin is Perry Zurn, a professor of philosophy at American University, and the two have investigated the many different ways a person can exhibit curiosity.

Bassett and Zurn have now published a new book on the subject. In Curious Minds: The Power of Connection, the twins draw on their previous research, as well as an expansive network of ideas from philosophy, history, education and art.

In an interview with The Guardian, Bassett explains how these threads wove together:

“It wasn’t clear at the beginning of our careers that we would even ever have a chance to write a book together because our areas were so wildly different,” Bassett says – but then, as postgraduates, Zurn was studying the philosophy of curiosity while Bassett was working on the neuroscience of learning. “And so that’s when we started talking. That talking led to seven years of doing research together,” Bassett says. “This book is a culmination of that.”

How exactly do philosophy and neuroscience complement each other? It all starts with the book’s first, and most deceptively simple question: what is curiosity? “Several investigators in science have underscored that perhaps the field isn’t even ready to define curiosity and how it’s different from other cognitive processes,” says Bassett. The ambiguity in the neuroscience literature motivated Bassett to turn to philosophy, “where there are really rich historical definitions and styles and subtypes that we can then put back into neuroscience and ask: ‘Can we see these in the brain?’”

Curious Minds: The Power of Connection is available now. Read Amelia Tait’s review “Are you a busybody, a hunter or a dancer? A new book about curiosity reveals all,” in The Guardian. 

This story originally appeared in Penn Engineering Today.

Applying Microrobotics in Endodontic Treatment and Diagnostics

by Beth Adams

Controlled and actuated by magnetic fields, these mircrorobots are capable of precisely targeting the apical region — the opening where blood vessels and nerve enter the tooth — in a root canal.

With its irregularities and anatomical complexities, the root canal system is one of the most clinically challenging spaces in the oral cavity. As a result, biofilm not fully cleared from the nooks and crannies of the canals remains a leading cause of treatment failure and persistent endodontic infections, and there are limited means to diagnose or assess the efficacy of disinfection. One day, clinicians may have a new tool to overcome these challenges in the form of microrobots.

In a proof-of-concept study, researchers from Penn Dental Medicine and its Center for Innovation & Precision Dentistry (CiPD), have shown that microrobots can access the difficult to reach surfaces of the root canal with controlled precision, treating and disrupting biofilms and even retrieving samples for diagnostics, enabling a more personalized treatment plan. The Penn team shared their findings on the use of two different microrobotic platforms for endodontic therapy in the August issue of the Journal of Dental Research; the work was selected for the issue’s cover.

“The technology could enable multimodal functionalities to achieve controlled, precision targeting of biofilms in hard-to-reach spaces, obtain microbiological samples, and perform targeted drug delivery, ” says Dr. Alaa Babeer, lead author of the study and a Penn Dental Medicine Doctor of Science in Dentistry (DScD) and endodontics graduate, who is now within the lab of Dr. Michel Koo, co-director of the CiPD .

In both platforms, the building blocks for the microrobots are iron oxide nanoparticles (NPs) that have both catalytic and magnetic activity and have been FDA approved for other uses. In the first platform, a magnetic field is used to concentrate the NPs in aggregated microswarms and magnetically control them to the apical area of the tooth to disrupt and retrieve biofilms through a catalytic reaction. The second platform uses 3D printing to create miniaturized helix-shaped robots embedded with iron oxide NPs. These helicoids are guided by magnetic fields to move within the root canal, transporting bioactives or drugs that can be released on site.

“This technology offers the potential to advance clinical care on a variety of levels,” says Dr. Koo, co-corresponding author of the study with Dr. Edward Steager, a senior research investigator in Penn’s School of Engineering and Applied Science. “One important aspect is the ability to have diagnostic as well as therapeutic applications. In the microswarm platform, we can not only remove the biofilm, but also retrieve it, enabling us identify what microorganisms caused the infection. In addition, the ability to conform to the narrow and difficult-to-reach spaces within the root canal allows for a more effective disinfection in comparison to the files and instrumentation techniques presently used.”

Continue reading at Penn Dental Medicine News

Michel Koo is a professor in the Department of Orthodontics and divisions of Community Oral Health and Pediatric Dentistry in Penn Dental Medicine and co-director of the Center for Innovation & Precision Dentistry. He is a member of the Penn Bioengineering Graduate Group.

A Novel Method for Monitoring the ‘Engine’ of Pregnancy

Combining optical measurements with ultrasound, an interdisciplinary team from the School of Arts & Sciences, Perelman School of Medicine, and CHOP developed a device to better measure blood flow and oxygenation in the placenta. (Image: Lin Wang)

A study published in Nature Biomedical Engineering details a novel method for imaging the placenta in pregnant patients as well as the results of a pilot clinical study. By combining optical measurements with ultrasound, the findings show how oxygen levels can be monitored noninvasively and provides a new way to generate a better understanding of this complex, crucial organ. This research was the result of a collaboration of the groups of the University of Pennsylvania’s Arjun Yodh and Nadav Schwartz with colleagues from the Children’s Hospital of Philadelphia (CHOP) and was led by postdoc Lin Wang.

Schwartz describes the placenta as the “engine” of pregnancy, an organ that plays a crucial role in delivering nutrients and oxygen to the fetus. Placental dysfunction can lead to complications such as fetal growth restriction, preeclampsia, and stillbirth. To increase knowledge about this crucial organ, the National Institute of Child Health and Human Development launched the Human Placenta Project in 2014. One focus of the program is to develop tools to assess human placental structure and function in real time, including optical devices.

For three years, the researchers optimized the design of their instrument and tested it in preclinical settings. The process involved integrating optical fibers with ultrasound probes, exploring various ultrasound transducers, and improving the multimodal technology so that measurements were stable, accurate, and reproducible while collecting data at the bedside. The resulting instrumentation now enables researchers to study the anatomy of the placenta while also collecting detailed functional information about placenta blood flow and oxygenation, capabilities that existing commercially devices do not have, the researchers say.

Because the placenta is located far below the body’s surface, one of the key technical challenges addressed by Wang, a postdoc in Yodh’s lab, was reducing background noise in the opto-electronic system. Light is scattered and absorbed when it travels through thick tissues, Yodh says, and the key for success was to reduce background interference so that the small amount of light that penetrates deep into the placenta and then returns is still large enough for a high-quality measurement.

“We’re sending a light signal that goes through the same deep tissues as the ultrasound. The extremely small amount of light that returns to the surface probe is then used to accurately assess tissue properties, which is only possible with very stable lasers, optics, and detectors,” says Yodh. “Lin had to overcome many barriers to improve the signal-to-noise ratio to the point where we trusted our data.”

Read the full story in Penn Today.

The authors are Lin Wang, Jeffrey M. Cochran, Kenneth Abramson, Lian He, Venki Kavuri, Samuel Parry, Arjun G. Yodh, and Nadav Schwartz from Penn; Tiffany Ko, Wesley B. Baker, and Rebecca L. Linn from the Children’s Hospital of Philadelphia, and David R. Busch, previously a research associate at Penn and now at the University of Texas Southwestern Medical School.

Arjun Yodh is the James M. Skinner Professor of Science in the Department of Physics and Astronomy in the School of Arts & Sciences at the University of Pennsylvania. He is a member of the Penn Bioengineering Graduate Group.

Nadav Schwartz is an Associate Professor in the Department of Obstetrics and Gynecology in Penn’s Perelman School of Medicine.

Lin Wang is a postdoc in the Department of Physics and Astronomy in Penn’s School of Arts & Sciences.

This research was supported by National Institutes of Health grants F31HD085731, R01NS113945, R01NS060653, P41EB015893, P41EB015893, T32HL007915, and U01HD087180.

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).

Decoding a Material’s ‘Memory’

by Erica K. Brockmeier

A suspension of particles of different sizes during shearing experiments conducted in the lab of Paulo Arratia, with arrows indicating particle “flow” and trajectories. In a new study published in Nature Physics, researchers detail the relationship between a disordered material’s individual particle arrangement and how it reacts to external stressors. The study also found that these materials have “memory” that can be used to predict how and when they will flow. (Image: Arratia lab)

New research published in Nature Physics details the relationship between a disordered material’s individual particle arrangement and how it reacts to external stressors. The study also found that these materials have “memory” that can be used to predict how and when they will flow. The study was led by Larry Galloway, a Ph.D. student in the lab of Paulo Arratia, and Xiaoguang Ma, a former postdoc in the lab of Arjun Yodh, in collaboration with researchers in the labs of Douglas Jerolmack and Celia Reina.

A disordered material is randomly arranged at the particle-scale, e.g. atoms or grains, instead of being systematically distributed—think of a pile of sand instead of a neatly stacked brick wall. Researchers in the Arratia lab are studying this class of materials as part of Penn’s Materials Research Science & Engineering Center, where one of the program’s focuses is on understanding the organization and proliferation of particle-scale rearrangements in disordered, amorphous materials.

The key question in this study was whether one could observe the structure of a disordered material and have some indication as to how stable it is or when it might begin to break apart. This is known as the yield point, or when the material “flows” and begins to move in response to external forces. “For example, if you look at the grains of a sand castle and how they are arranged, can I tell you whether the wind can blow it over or if it has to be hit hard to fall over?” says Arratia. “We want to know, just by looking at the way the particles are arranged, if we can say anything about the way they’re going to flow or if they are going to flow at all.”

While it has been known that individual particle distribution influences yield point, or flow, in disordered materials, it has been challenging to study this phenomenon since the field lacks ways to “quantify” disorder in such materials. To address this challenge, the researchers collaborated with colleagues from across campus to combine expertise across the fields of experimentation, theory, and simulations.

Read the full story in Penn Today.

The authors are Larry Galloway, Erin Teich, Christoph Kammer, Ian Graham, Celia Reina, Douglas Jerolmack, Arjun Yodh, and Paulo Arratia from Penn; Xiaoguang Ma, previously a postdoc at Penn and now at the Southern University of Science and Technology in Shenzhen, China; and Nathan Keim, previously a postdoc at Penn and now at Pennsylvania State University.

Arjun Yodh is the James M. Skinner Professor of Science in the Department of Physics and Astronomy in Penn’s School of Arts & Sciences and a member of the Penn Bioengineering Graduate Group.

Paulo Arratia is a professor in the departments of Mechanical Engineering and Applied Mechanics and Chemical and Biomolecular Engineering in the School of Engineering and Applied Science at the University of Pennsylvania.

Douglas Jerolmack is a professor in the Department of Earth and Environmental Science in Penn’s School of Arts & Sciences and in the Department of Mechanical Engineering and Applied Mechanics at Penn Engineering.

Celia Reina is the William K. Gemmill Term Assistant Professor in the Department of Mechanical Engineering and Applied Mechanics at Penn Engineering.