Shapeshifting Microrobots Can Brush and Floss Teeth

by Katherine Unger Baillie

In a proof-of-concept study, researchers from the School of Dental Medicine and School of Engineering and Applied Science shows that a hands-free system could effectively automate the treatment and removal of tooth-decay-causing bacteria and dental plaque. (Illustration: Melissa Pappas)

A shapeshifting robotic microswarm may one day act as a toothbrush, rinse, and dental floss in one.

The technology, developed by a multidisciplinary team at the University of Pennsylvania, is poised to offer a new and automated way to perform the mundane but critical daily tasks of brushing and flossing. It’s a system that could be particularly valuable for those who lack the manual dexterity to clean their teeth effectively themselves.

The building blocks of these microrobots are iron oxide nanoparticles that have both catalytic and magnetic activity. Using a magnetic field, researchers could direct their motion and configuration to form either bristlelike structures that sweep away dental plaque from the broad surfaces of teeth, or elongated strings that can slip between teeth like a length of floss. In both instances, a catalytic reaction drives the nanoparticles to produce antimicrobials that kill harmful oral bacteria on site.

Experiments using this system on mock and real human teeth showed that the robotic assemblies can conform to a variety of shapes to nearly eliminate the sticky biofilms that lead to cavities and gum disease. The Penn team shared their findings establishing a proof-of-concept for the robotic system in the journal ACS Nano.

“Routine oral care is cumbersome and can pose challenges for many people, especially those who have hard time cleaning their teeth” says Hyun (Michel) Koo, a professor in the Department of Orthodontics and divisions of Community Oral Health and Pediatric Dentistry in Penn’s School of Dental Medicine and co-corresponding author on the study. “You have to brush your teeth, then floss your teeth, then rinse your mouth; it’s a manual, multistep process. The big innovation here is that the robotics system can do all three in a single, hands-free, automated way.”

Read the full story in Penn Engineering Today.

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

Edward Steager is a senior research investigator in Penn’s School of Engineering and Applied Science.

Koo and Steager’s coauthors on the paper are Penn Dental Medicine’s Min Jun Oh, Alaa Babeer, Yuan Liu, and Zhi Ren and Penn Engineering’s Jingyu Wu, David A. Issadore, Kathleen J. Stebe, and Daeyeon Lee.

This work was supported in part by the National Institute for Dental and Craniofacial Research (grants DE025848 and DE029985), Procter & Gamble, and the Postdoctoral Research Program of Sungkyunkwan University.

Bioengineering Student Savan Patel Receives the 2022 C. William Hall Scholarship

Savan Patel

Savan Patel, a junior studying Bioengineering and Finance in the Jerome Fisher Management and Technology dual degree program, was selected as the recipient of the 2022 C. William Hall Scholarship from the Society for Biomaterials. The C. William Hall Scholarship is named in honor of the Society for Biomaterials’ first president and is awarded annually “to a junior or senior undergraduate pursuing a bachelor’s degree in bioengineering or a related discipline focusing on biomaterials.” As this year’s recipient, Savan will receive complimentary membership to the Society and will have expenses paid to the Society’s annual meeting being held April 27-30, 2022 in Baltimore, Maryland.

Savan is currently a member of the lab of Michael J. Mitchell, Skirkanich Assistant Professor of Innovation in Bioengineering. Savan’s research interests lie in the interface of drug delivery and immunoengineering with a particular focus on T cell delivery. His current project involves the use of modified cholesterol molecules to improve the delivery of nucleic acids (i.e., mRNA) to cell populations using lipid nanoparticles.

Lipid nanoparticles (LNPs) are a clinically proven delivery platform for nucleic acid therapeutics. One drawback of these particles is their high cellular recycling rate. Savan and the members of the Mitchell lab are working to reduce this recycling by leveraging cellular processes and incorporating modified molecules into our lipid nanoparticle formulations. The focus of Savan’s project is on modifying cholesterol, a molecule that is important to both our LNP formulations and cell membranes. The goal is to generate a more potent delivery platform to improve current therapeutics.

Following graduation, Savan intends to pursue a Ph.D. in Bioengineering.

Penn Engineers Secure Wellcome Leap Contract for Lipid Nanoparticle Research Essential in Delivery of RNA Therapies

by Melissa Pappas

The Very Large Scale Microfluidic Integration (VLSMI) platform, a technology developed by the Penn researchers, contains hundreds of mixing channels for mass-producing mRNA-carrying lipid nanoparticles.

Penn Engineering secured a multi-million-dollar contract with Wellcome Leap under the organization’s $60 million RNA Readiness + Response (R3) program, which is jointly funded with the Coalition for Epidemic Preparedness Innovations (CEPI). Penn Engineers aim to create “on-demand” manufacturing technology that can produce a range of RNA-based vaccines.

The Penn Engineering team features Daeyeon Lee, Evan C Thompson Term Chair for Excellence in Teaching and Professor in Chemical and Biomolecular Engineering, Michael Mitchell, Skirkanich Assistant Professor of Innovation in Bioengineering, David Issadore, Associate Professor in Bioengineering and Electrical and Systems Engineering, and Sagar Yadavali, a former postdoctoral researcher in the Issadore and Lee labs and now the CEO of InfiniFluidics, a spinoff company based on their research. Drew Weissman of the Perelman School of Medicine, whose foundational research directly continued to the development of mRNA-based COVID-19 vaccines, is also a part of this interdisciplinary team.

The success of these COVID-19 vaccines has inspired a fresh perspective and wave of research funding for RNA therapeutics across a wide range of difficult diseases and health issues. These therapeutics now need to be equitably and efficiently distributed, something currently limited by the inefficient mRNA vaccine manufacturing processes which would rapidly translate technologies from the lab to the clinic.

Read more in Penn Engineering Today.

New Lipid Nanoparticles Improve mRNA Delivery for Engineering CAR T Cells

by Melissa Pappas

The Penn researchers’ latest paper on the design of lipid nanoparticles was featured on the cover of the most recent edition of the journal Nano Letters.

From COVID vaccines to cancer immunotherapies to the potential for correcting developmental disorders in utero, mRNA-based approaches are a promising tool in the fight against a wide range of diseases. These treatments all depend on providing a patient’s cells with genetic instructions for custom proteins and other small molecules, meaning that getting those instructions inside the target cells is of critical importance.

The current delivery method of choice uses lipid nanoparticles (LNPs). Thanks to surfaces customized with binding and signaling molecules, they encapsulate mRNA sequences and smuggle them through the cell membrane. But with a practically unlimited number of variables in the makeup of those surfaces and molecules, figuring out how to design the most effective LNP is a fundamental challenge.

Now, in a study featured on the cover of the journal Nano Letters, researchers from the University of Pennsylvania’s School of Engineering and Applied Science and Perelman School of Medicine have now shown how to computationally optimize the design of these delivery vehicles.

Using an established methodology for comparing a wide range of variables known as “orthogonal design of experiments,” the researchers simultaneously tested 256 candidate LNPs. They found the frontrunner was three times better at delivering mRNA sequences into T cells than the current standard LNP formulation for mRNA delivery.

The study was led by Michael Mitchell, Skirkanich Assistant Professor of Innovation in the Department of Bioengineering in Penn’s School of Engineering and Applied Science, and Margaret Billingsley, a graduate student in his lab.

Read the full story in Penn Engineering Today.

Michael Mitchell Receives the 2022 SFB Young Investigator Award

by Ebonee Johnson

Michael Mitchell, Ph.D.

Michael Mitchell, Skirkanich Assistant Professor of Innovation in the Department of Bioengineering, has been awarded the 2022 Society for Biomaterials (SFB) Young Investigator Award for his “outstanding achievements in the field of biomaterials research.”

The Society for Biomaterials is a multidisciplinary society of academic, healthcare, governmental and business professionals dedicated to promoting advancements in all aspects of biomaterial science, education and professional standards to enhance human health and quality of life.

Mitchell, whose research lies at the interface of biomaterials science, drug delivery, and cellular and molecular bioengineering to fundamentally understand and therapeutically target biological barriers, is specifically being recognized for his development of the first nanoparticle RNAi therapy to treat multiple myeloma, an incurable hematologic cancer that colonizes in bone marrow.

“Before this, no one in the drug delivery field has developed an effective gene delivery system to target bone marrow,” said United States National Medal of Science recipient Robert S. Langer in Mitchell’s award citation. “Mike is a standout young investigator and leader that intimately understands the importance of research and collaboration at the interface of nanotechnology and medicine.”

Academic recipients of the SFB Young Investigator Award should not exceed the rank of Assistant Professor and must not be tenured at the time of nomination. The award includes a $1,000 endowment.

This story originally appeared in Penn Engineering Today.

With a ‘Liquid Assembly Line,’ Penn Researchers Produce mRNA-Delivering-Nanoparticles a Hundred Times Faster than Standard Microfluidic Technologies

by Evan Lerner

Michael Mitchell, Sarah Shepherd and David Issadore pose with their new device.

The COVID vaccines currently being deployed were developed with unprecedented speed, but the mRNA technology at work in some of them is an equally impressive success story. Because any desired mRNA sequence can be synthesized in massive quantities, one of the biggest hurdles in a variety of mRNA therapies is the ability to package those sequences into the lipid nanoparticles that deliver them into cells.

Now, thanks to manufacturing technology developed by bioengineers and medical researchers at the University of Pennsylvania, a hundred-fold increase in current microfluidic production rates may soon be possible.

The researchers’ advance stems from their design of a proof-of-concept microfluidic device containing 128 mixing channels working in parallel. The channels mix a precise amount of lipid and mRNA, essentially crafting individual lipid nanoparticles on a miniaturized assembly line.

This increased speed may not be the only benefit; more precisely controlling the nanoparticles’ size could make treatments more effective. The researchers tested the lipid nanoparticles produced by their device in a mouse study, showing they could deliver therapeutic RNA sequences with four-to-five times greater activity than those made by conventional methods.

The study was led by Michael Mitchell, Skirkanich Assistant Professor of Innovation in Penn Engineering’s Department of Bioengineering, and David Issadore, Associate Professor in Penn Engineering’s Department of Bioengineering, along with Sarah Shepherd, a doctoral student in both of their labs. Rakan El-Mayta, a research engineer in Mitchell’s lab, and Sagar Yadavali, a postdoctoral researcher in Issadore’s lab, also contributed to the study.

They collaborated with several researchers at Penn’s Perelman School of Medicine: postdoctoral researcher Mohamad-Gabriel Alameh, Lili Wang, Research Associate Professor of Medicine, James M. Wilson, Rose H. Weiss Orphan Disease Center Director’s Professor in the Department of Medicine, Claude Warzecha, a senior research investigator in Wilson’s lab, and Drew Weissman, Professor of Medicine and one of the original developers of the technology behind mRNA vaccines.

It was published in the journal Nano Letters.

“We believe that this microfluidic technology has the potential to not only play a key role in the formulation of current COVID vaccines,” says Mitchell, “but also to potentially address the immense need ahead of us as mRNA technology expands into additional classes of therapeutics.”

Read the full story in Penn Engineering Today.

Modified Nanoparticles Can Stop Osteoarthritis Development

Zhiliang Cheng

As we age, the cushioning cartilage between our joints begins to wear down, making it harder and more painful to move. Known as osteoathritis, this extremely common condition has no known cure; if the symptoms can’t be managed, the affected joints must be surgically replaced.

Now, researchers are exploring whether their specially designed nanoparticles can deliver a new inflammation inhibitor to joints, targeting a previously overlooked enzyme called sPLA2.

Zhiliang Cheng, a research associate professor in the Department of Bioengineering, recently collaborated with members of Penn Medicine’s McKay Orthopaedic Research Laboratory, on a study of this approach, published in the journal Science Advances.

The normal function of sPLA2 is to provide lipids (fats) that promote a variety of inflammation processes. The enzyme is always present in cartilage tissue, but typically in low levels. However, when the researchers examined mouse and human cartilage taken from those with osteoarthritis, disproportionately high levels of the enzyme were discovered within the tissue’s structure and cells.

“This marked increase strongly suggests that sPLA2 plays a role in the development of osteoarthritis,” said the study’s corresponding author, Zhiliang Cheng, PhD, a research associate professor of Bioengineering. “Being able to demonstrate this showed that we were on the right track for what could be a potent target for the disease.”

The next step was for the study team – which included lead author Yulong Wei, MD, a researcher in Penn Medicine’s McKay Orthopaedic Research Laboratory – to put together a nanoparticle loaded with an sPLA2 inhibitor. This would block the activity of sPLA2 enzyme and, they believed, inflammation. These nanoparticles were mixed with animal knee cartilage in a lab, then observed as they diffused deeply into the dense cartilage tissue. As time progressed, the team saw that the nanoparticles stayed there and did not degrade significantly or disappear. This was important for the type of treatment the team envisioned.

Continue reading at Penn Medicine News.

Originally posted in Penn Engineering Today.

Michael Mitchell on Keeping mRNA Vaccines Viable

A National Institute of Allergy and Infectious Diseases lab freezer used for COVID-19 vaccine research. Both of the current mRNA-based COVID vaccines require ultra-cold freezers to prevent their mRNA from degrading, spurring research into other ways to stabilize the molecule.

As the technology behind two of the COVID-19 vaccines, Messenger RNA (mRNA) is having a moment. A single-stranded counterpart to DNA, mRNA translates its genetic code into proteins; by injecting mRNA engineered to produce proteins found on the exterior of the virus, the vaccine can train a person’s immune system to recognize the real thing without making them sick.

However, because mRNA is a relatively unstable molecule, distributing these vaccines involves extra logistical challenges. Doses must be transported and stored at ultra-cold temperatures to make sure the mRNA inside doesn’t degrade and lose the genetic information it carries.

Michael Mitchell
Michael Mitchell

As mRNA vaccines and other therapies take off, researchers are looking for other ways to forestall this degradation. One of them is Michael J. Mitchell, Skirkanich Assistant Professor of Innovation in the Department of Bioengineering, who is studying the use of lipid nanoparticles to encapsulate and protect mRNA on its way into the cell. That sort of packaging would be particularly beneficial in proposed mRNA therapies for certain genetic disorders, which aim to deliver the correct protein-making instructions to specific organs, or even a fetus in utero.

But for stabilizing mRNA for vaccine distribution, many other strategies are being explored. In “Keeping covid vaccines cold isn’t easy. These ideas could help,” Wudan Yan of MIT Technology Review reached out to Mitchell for insight on LIONs, or lipid inorganic nanoparticles. These nanoparticles work the opposite way of Mitchell’s organic ones, with the mRNA stabilized by binding to their exteriors.

Continue reading at MIT Technology Review.

Originally posted in Penn Engineering Today.

‘RNA worked for COVID-19 vaccines. Could it be used to treat cancer and rare childhood diseases?’

William H. Peranteau, Michael J. Mitchell, Margaret Billingsley, Meghana Kashyap, and Rachel Riley (Clockwise from top left)

As COVID-19 vaccines roll out, the concept of using mRNA to fend off viruses has become a part of the public dialogue. However, scientists have been researching how mRNA can be used to in life-saving medical treatments well before the pandemic.

The “m” in “mRNA” is for “messenger.” A single-stranded counterpart to DNA, it translates the genetic code into the production of proteins, the building blocks of life. The Moderna and Pfizer COVID-19 vaccines work by introducing mRNA sequences that act as a set of instructions for the body to produce proteins that mimic parts of the virus itself. This prepares the body’s immune response to recognize the real virus and fight it off.

Because it can spur the production of proteins that the body can’t make on its own, mRNA therapies also have the potential to slow or prevent genetic diseases that develop before birth, such as cystic fibrosis and sickle-cell anemia.

However, because mRNA is a relatively unstable molecule that degrades quickly, it needs to be packaged in a way that maintains its integrity as its delivered to the cells of a developing fetus.

To solve this challenge, Michael J. Mitchell, Skirkanich Assistant Professor of Innovation in the Department of Bioengineering, is researching the use of lipid nanoparticles as packages that transport mRNA into the cell. He and William H. Peranteau, an attending surgeon in the Division of General, Thoracic and Fetal Surgery and the Adzick-McCausland Distinguished Chair in Fetal and Pediatric Surgery at Children’s Hospital of Philadelphia, recently co-authored a “proof-of-concept” paper investigating this technique.

In this study, published in Science Advances, Mitchel examined which nanoparticles were optimal in the transport of mRNA to fetal mice. Although no disease or organ was targeted in this study, the ability to administer mRNA to a mouse while still in the womb was demonstrated, and the results are promising for the next stages of targeted disease prevention in humans.

Mitchel spoke with Tom Avril at The Philadelphia Inquirer about the mouse study and its implications for treatment of rare infant diseases through the use of mRNA, ‘the messenger of life.’

Penn bioengineering professor Michael J. Mitchell, the other senior author of the mouse study, tested various combinations of lipids to see which would work best.

The appeal of the fatty substances is that they are biocompatible. In the vaccines, for example, two of the four lipids used to make the delivery spheres are identical to lipids found in the membranes of human cells — including plain old cholesterol.

When injected, the spheres, called nanoparticles, are engulfed by the person’s cells and then deposit their cargo, the RNA molecules, inside. The cells respond by making the proteins, just as they make proteins by following the instructions in the person’s own RNA. (Important reminder: The RNA in the vaccines cannot become part of your DNA.)

Among the different lipid combinations that Mitchell and his lab members tested, some were better at delivering their cargo to specific organs, such as the liver and lungs, meaning they could be a good vehicle for treating disease in those tissues.

Continue reading Tom Avril’s ‘RNA worked for COVID-19 vaccines. Could it be used to treat cancer and rare childhood diseases?’ at The Philadelphia Inquirer.

Penn Engineering and CHOP Researchers Identify Nanoparticles that Could Be Used in Therapeutic mRNA Delivery before Birth

by Evan Lerner

William H. Peranteau, Michael J. Mitchell, Margaret Billingsley, Meghana Kashyap, and Rachel Riley (Clockwise from top left)

Researchers at Children’s Hospital of Philadelphia and the School of Engineering and Applied Science at the University of Pennsylvania have identified ionizable lipid nanoparticles that could be used to deliver mRNA as part of fetal therapy. The proof-of-concept study, published today in Science Advances, engineered and screened a number of lipid nanoparticle formulations for targeting mouse fetal organs and has laid the groundwork for testing potential therapies to treat genetic diseases before birth.

“This is an important first step in identifying nonviral mediated approaches for delivering cutting-edge therapies before birth,” said co-senior author William H. Peranteau, MD, an attending surgeon in the Division of General, Thoracic and Fetal Surgery and the Adzick-McCausland Distinguished Chair in Fetal and Pediatric Surgery at CHOP. “These lipid nanoparticles may provide a platform for in utero mRNA delivery, which would be used in therapies like fetal protein replacement and gene editing.”

Michael J. Mitchell, Skirkanich Assistant Professor of Innovation in Penn Engineering’s Department of Bioengineering, is the other co-senior author of the study. The co-first authors are Mitchell Lab members Rachel Riley, a postdoctoral fellow, and Margaret Billingsley, a graduate student, and Peranteau Lab member Meghana Kashyap, a research fellow.

Recent advances in DNA sequencing technology and prenatal diagnostics have made it possible to diagnose many genetic diseases before birth. Some of these diseases are treated by protein or enzyme replacement therapies after birth, but by then, some of the damaging effects of the disease have taken hold. Thus, applying therapies while the patient is still in the womb has the potential to be more effective for some conditions. The small fetal size allows for maximal therapeutic dosing, and the immature fetal immune system may be more tolerant of replacement therapy.

Read the full story in Penn Engineering Today.

NB: Rachel Riley is now Assistant Professor in Biomedical Engineering at Rowan University.