hydrogels – Penn Bioengineering Blog

Bicontinuous materials, like this representation of a cube of gelatin and hyaluronic acid, have greater internal surface area, allowing cells to travel faster between two points. (Credit: Karen Xu)

One of the most important but least understood aspects of healing is cell migration, or the process of cells moving from one part of the body to another. “If you are an ambulance out in the woods,” says Karen Xu, an M.D/Ph.D. student in Medicine and Bioengineering, “and there are no paths for you to move forward, it will be a lot harder for you to get to a site that needs you.”

Earlier this year, Xu co-authored a paper in Nature Communications describing a new cue to help cells get to where they need to go: a material made chiefly of hyaluronic acid and gelatin, two gooey substances commonly found outside cells in joints and connective tissue.

“Hundreds of thousands of people tear their meniscus every year,” says Robert Mauck, Mary Black Ralston Professor in Orthopaedic Surgery in Penn Medicine and Professor in Bioengineering at Penn Engineering and one of Xu’s advisors, as well as a senior author on the paper. “This material could potentially speed up their recovery.”

What makes the material — known as a hydrogel due to its blend of gelatinous matter and water — unique is that the combination of hyaluronic acid and gelatin forms a complex network of paths, providing cells many different ways to travel between two points.

This property is known as bicontinuity, and is exemplified by two discrete continuous phases that are each connected throughout the entire volume of the material (for example with a sponge, with phases of cellulose and air; in the hydrogel, this is comprised of gelatin and hyaluronic acid) resulting in a dizzying array of patterns that dramatically increase the surface area inside the material.

To test the hydrogel’s efficacy, Xu and her collaborators — including co-advisor Jason Burdick, formerly the Robert D. Bent Professor in Bioengineering at Penn Engineering and now the Bowman Endowed Professor at the University of Colorado Boulder, and the paper’s other senior author — first created several different versions of the hydrogel to find the sweet spot at which the constituents formed the bicontinuous structure and had the highest internal surface area. “We found that a precise combination of the various hydrogel components and control over their mixing was needed to form the bicontinuous structure,” says Burdick.

Read the full story in Penn Engineering Today.

June 16, 2022June 16, 2022

Taimoor Qazi Appointed Assistant Professor at Purdue University

The Department of Bioengineering is proud to congratulate Taimoor H. Qazi, Ph.D. on his appointment as Assistant Professor in the Weldon School of Biomedical Engineering at Purdue University. Qazi’s appointment will begin in Fall 2022.

Qazi obtained his Ph.D. at the Technical University of Berlin and the Charité Hospital in Berlin, Germany working on translational approaches for musculoskeletal tissue repair using biomaterials and stem cells under the co-advisement of Georg Duda, Director of the Berlin Institute of Health and David Mooney, Mercator Fellow at Charité – Universitätsmedizin Berlin. After arriving at Penn in 2019, Qazi performed research on microscale granular hydrogels in the Polymeric Biomaterials Laboratory of Jason Burdick, Adjunct Professor in Bioengineering at Penn and Bowman Endowed Professor in Chemical and Biological Engineering at the University of Colorado, Boulder. While conducting postdoctoral research, Qazi also collaborated with the groups of David Issadore, Associate Professor in Bioengineering and in Electrical and Systems Engineering, and Daeyeon Lee, Professor and Evan C. Thompson Term Chair for Excellence in Teaching in Chemical and Biomolecular Engineering and member of the Penn Bioengineering Graduate Group. Qazi’s postdoctoral research was supported through a fellowship from the German Research Foundation, and resulted in several publications in high-profile journals, including Advanced Materials, Cell Stem Cell, Small, and ACS Biomaterials Science and Engineering.

“Taimoor has done really fantastic research as a postdoctoral fellow in the group,” says Burdick. “Purdue has a long history of excellence in biomaterials research and will be a great place for him to build a strong research program.”

Qazi’s future research program will engineer biomaterials to make fundamental and translational advances in musculoskeletal tissue engineering, including the study of how rare tissue-resident cells respond to spatiotemporal signals and participate in tissue repair, and developing modular hydrogels that permit minimally invasive delivery for tissue regeneration. The ultimate goal is to create scalable, translational, and biologically inspired healthcare solutions that benefit a patient population that is expected to grow manifold in the coming years.

Qazi is looking to build a strong and inclusive team of scientists and engineers with diverse backgrounds interested in tackling problems at the interface of translational medicine, materials science, bioengineering, and cell biology, and will be recruiting graduate students immediately. Interested students can contact him directly at thqazi@seas.upenn.edu.

“I am excited to launch my independent research career at a prestigious institution like Purdue,” says Qazi. “Being at Penn and particularly in the Department of Bioengineering greatly helped me prepare for the journey ahead. I am grateful for Jason’s mentorship over the years and the access to resources provided by Jason, Dave Issadore, Ravi, Dave Meany and other faculty which support the training and professional development of postdoctoral fellows in Penn Bioengineering.”

Congratulations to Dr. Qazi from everyone at Penn Bioengineering!

December 14, 2021December 20, 2021

Penn Bioengineering Celebrates Five Researchers on Highly Cited Researchers 2021 List

The Department of Bioengineering is proud to announce that five of our faculty have been named on the annual Highly Cited Researchers™ 2021 list from Clarivate:

Dani S. Bassett, J. Peter Skirkanich Professor in Bioengineering and in Electrical and Systems Engineering
Bassett runs the Complex Systems lab which tackles problems at the intersection of science, engineering, and medicine using systems-level approaches, exploring fields such as curiosity, dynamic networks in neuroscience, and psychiatric disease. They are a pioneer in the emerging field of network science which combines mathematics, physics, biology and systems engineering to better understand how the overall shape of connections between individual neurons influences cognitive traits.

Robert D. Bent Chair — Jason Burdick, Ph.D.

Jason A. Burdick, Robert D. Bent Professor in Bioengineering
Burdick runs the Polymeric Biomaterials Laboratory which develops polymer networks for fundamental and applied studies with biomedical applications with a specific emphasis on tissue regeneration and drug delivery. The specific targets of his research include: scaffolding for cartilage regeneration, controlling stem cell differentiation through material signals, electrospinning and 3D printing for scaffold fabrication, and injectable hydrogels for therapies after a heart attack.

César de la Fuente, Presidential Assistant Professor in Bioengineering and Chemical & Biomedical Engineering in Penn Engineering and in Microbiology and Psychiatry in the Perelman School of Medicine
De la Fuente runs the Machine Biology Group which combines the power of machines and biology to prevent, detect, and treat infectious diseases. He pioneered the development of the first antibiotic designed by a computer with efficacy in animals, designed algorithms for antibiotic discovery, and invented rapid low-cost diagnostics for COVID-19 and other infections.

Carl H. June, Richard W. Vague Professor in Immunotherapy in the Perelman School of Medicine and member of the Bioengineering Graduate Group
June is the Director for the Center for Cellular Immunotherapies and the Parker Institute for Cancer Therapy and runs the June Lab which develops new forms of T cell based therapies. June’s pioneering research in gene therapy led to the FDA approval for CAR T therapy for treating acute lymphoblastic leukemia (ALL), one of the most common childhood cancers.

Vivek Shenoy, Eduardo D. Glandt President’s Distinguished Professor in Bioengineering, Mechanical Engineering and Applied Mechanics (MEAM), and in Materials Science and Engineering (MSE)
Shenoy runs the Theoretical Mechanobiology and Materials Lab which develops theoretical concepts and numerical principles for understanding engineering and biological systems. His analytical methods and multiscale modeling techniques gain insight into a myriad of problems in materials science and biomechanics.

The highly anticipated annual list identifies researchers who demonstrated significant influence in their chosen field or fields through the publication of multiple highly cited papers during the last decade. Their names are drawn from the publications that rank in the top 1% by citations for field and publication year in the Web of Science™ citation index.

Bassett and Burdick were both on the Highly Cited Researchers list in 2019 and 2020.

The methodology that determines the “who’s who” of influential researchers draws on the data and analysis performed by bibliometric experts and data scientists at the Institute for Scientific Information™ at Clarivate. It also uses the tallies to identify the countries and research institutions where these scientific elite are based.

David Pendlebury, Senior Citation Analyst at the Institute for Scientific Information at Clarivate, said: “In the race for knowledge, it is human capital that is fundamental and this list identifies and celebrates exceptional individual researchers who are having a great impact on the research community as measured by the rate at which their work is being cited by others.”

The full 2021 Highly Cited Researchers list and executive summary can be found online here.

December 7, 2021

BE Seminar: “Tissue-Inspired Synthetic Biomaterials” (Shelly Peyton)

Shelly R. Peyton, Ph.D.

Speaker: Shelly R. Peyton, Ph.D.
Professor, Armstrong Professional Development Professor
Chemical Engineering, Biomedical Engineering Adjunct
College of Engineering
University of Massachusetts Amherst

Date: Thursday, December 9, 2021
Time: 3:30-4:30 PM EST
Zoom – check email for link
This seminar will be held virtually, but students registered for BE 699 can gather to watch in Moore 216.

Abstract: Improved experimental model systems are critically needed to better understand cancer progression and bridge the gap between lab bench proof-of-concept studies, validation in animal models, and eventual clinical application. Many methods exist to create biomaterials, including hydrogels, which we use to study cells in contexts more akin to what they experience in the human body. Our lab has multiple approaches to create such biomaterials, based on combinations of poly(ethylene glycol) (PEG) with peptides and zwitterions. In this presentation, I will discuss our synthetic approaches to building life-like materials, how we use these systems to grow cells and understand how a cell’s environment, particularly the extracellular matrix regulates cancer cell growth, dormancy, and drug sensitivity.

Shelly Peyton Bio: Shelly Peyton is the Armstrong Professor and Graduate Program Director, and chair of the Diversity, Equity, and Inclusion (DEI) committee of Chemical Engineering at the University of Massachusetts Amherst. She is co-director of the Models 2 Medicine Center in the Institute for Applied Life Sciences. She received her B.S. in Chemical Engineering from Northwestern University in 2002 and went on to obtain her MS and PhD in Chemical Engineering from the University of California, Irvine. She was then an NIH Kirschstein post-doctoral fellow in the Biological Engineering department at MIT before starting her academic appointment at UMass in 2011. Shelly leads an interdisciplinary group of engineers and molecular cell biologists seeking to create and apply novel biomaterials platforms toward new solutions to grand challenges in human health. Her lab’s unique approach is using our engineering expertise to build simplified models of human tissue with synthetic biomaterials. They use these systems to understand 1) the physical relationship between metastatic breast cancer cells and the tissues to which they spread, 2) the role of matrix remodeling in drug resistance, and 3) how to create bioinspired mechanically dynamic and activatable biomaterials. Among other honors for her work, Shelly was a 2013 Pew Biomedical Scholar, received a New Innovator Award from the NIH, and she was awarded a CAREER grant from the NSF. Shelly is co-PI with Jeanne Hardy on the Biotechnology (BTP) NIH T32 program and is a co-PI of the PREP program at UMass, which brings students from URM groups to UMass for a 1-year post-BS study to help prepare them for graduate school.

May 12, 2021May 12, 2021

Bioengineering Graduate Students Take the Annual BETA Day Online

By GABE Outreach Chairs and Ph.D. students David Gonzalez-Martinez and David Mai

Every spring, the Graduate Association of Bioengineers (GABE) at Penn partners up with iPraxis, an educational non-profit organization based in Philadelphia, to organize BETA Day, an event that brings together Bioengineering graduate students and local Philadelphia grade school students to introduce them to the field of bioengineering, the life of graduate students, and hands-on scientific demonstrations. Due to COVID-19 restrictions, we adapted the traditional in-person BETA Day into a virtual event on Zoom. This year, we assembled kits containing the necessary materials for our chosen demonstrations and worked with iPraxis to coordinate their delivery to partner schools and their students. This enabled students to perform their demonstrations in a hands-on manner from their own homes; over 40 students were able to participate in extracting their own DNA and making biomaterials with safe household materials.

Michelle Johnson presents on her work in robotics

The day began with a fantastic lecture by Michelle Johnson, Associate Professor in Bioengineering and Physical Medicine and Rehabilitation, who introduced students to the field of rehabilitation robotics and shared her experience as a scientist. Students then learned about DNA and biomaterials through lectures mediated by the graduate students Dayo Adetu and Puneeth Guruprasad. After each lecture, students broke into breakout rooms with graduate student facilitators where they were able to get some hands-on scientific experience as they extracted DNA from their cheek cells and fabricated alginate hydrogels. Michael Sobrepera, a graduate student in Dr. Johnson’s lab, concluded the event by giving a lecture on the process of robotics development and discussed where the field is heading and some important considerations for the field.

Dayo Adetu, Bioengineering Master’s student and GABE President, teaches the students about Genetic Engineering

While yet another online event may seem unexciting, throughout the lectures students remained exceptionally engaged and raised fantastic questions ranging from the accessibility of low income communities to novel robotic therapeutic technologies to the bioethical questions robotic engineers will face as technologies advance. The impact of BETA day was evident as the high school students began to discuss the possible majors they would like to pursue for their bachelor’s degrees. Events like BETA Day give a glimpse into possible STEM fields and careers students can pursue.

November 6, 2020November 4, 2020

Magnetic Field and Hydrogels Could Be Used to Grow New Cartilage

by Frank Otto

MRI Knee joint or Magnetic resonance imaging sagittal view for detect tear or sprain of the anterior cruciate ligament (ACL).

Using a magnetic field and hydrogels, a team of researchers in the Perelman School of Medicine have demonstrated a new possible way to rebuild complex body tissues, which could result in more lasting fixes to common injuries, such as cartilage degeneration. This research was published in Advanced Materials.

“We found that we were able to arrange objects, such as cells, in ways that could generate new, complex tissues without having to alter the cells themselves,” says the study’s first author, Hannah Zlotnick, a graduate student in bioengineering who works in the McKay Orthopaedic Research Laboratory at Penn Medicine. “Others have had to add magnetic particles to the cells so that they respond to a magnetic field, but that approach can have unwanted long-term effects on cell health. Instead, we manipulated the magnetic character of the environment surrounding the cells, allowing us to arrange the objects with magnets.”

In humans, tissues like cartilage can often break down, causing joint instability or pain. Often, the breakdown isn’t in total, but covers an area, forming a hole. Current fixes are to fill those holes in with synthetic or biologic materials, which can work but often wear away because they are not the same exact material as what was there before. It’s similar to fixing a pothole in a road by filling it with gravel and making a tar patch: The hole will be smoothed out but eventually wear away with use because it’s not the same material and can’t bond the same way.

What complicates fixing cartilage or other similar tissues is that their makeup is complex.

“There is a natural gradient from the top of cartilage to the bottom, where it contacts the bone,” Zlotnick explains. “Superficially, or at the surface, cartilage has a high cellularity, meaning there is a higher number of cells. But where cartilage attaches to the bone, deeper inside, its cellularity is low.”

So the researchers, which included senior author Robert Mauck, PhD, director of the McKay Lab and a professor of Orthopaedic Surgery and Bioengineering, sought to find a way to fix the potholes by repaving them instead of filling them in. With that in mind, the research team found that if they added a magnetic liquid to a three-dimensional hydrogel solution, cells, and other non-magnetic objects including drug delivery microcapsules, could be arranged into specific patterns that mimicked natural tissue through the use of an external magnetic field.

Read more at Penn Medicine News.

July 26, 2017July 26, 2017

Burdick Recognized by NIH in Two Programs

Jason Burdick, Ph.D., professor in the Department of Bioengineering, was among the recent recipients of a grant from Sharing Partnership for Innovative Research in Translation (SPIRiT), a pilot grant program awarded by the Clinical and Translational Science Award (CTSA) division of the National Institutes of Health (NIH).

Dr. Burdick’s research, undertaken with Albert Sinusas, MD, of Yale, concerns the development of a noninvasive treatment to limit the damage to the heart caused by heart attacks, which are suffered annually by almost 750,000 Americans. Using single-photo emission computed tomography (SPECT), the technique identifies the damaged heart muscle on the basis of enzymes activated by damage, followed by the targeted administration of bioengineered hydrogels for the delivery of therapeutics

Dr. Burdick says, “This research has the potential to advance treatments for the many individuals with heart attacks who have few current options. Our approach uses injectable materials and advanced imaging techniques to address the changes in protease levels after heart attacks that can lead to tissue damage.”

In other news, Dr. Burdick was one of 12 researchers named by the NIH’s Center for Engineering Complex Tissues to lead collaborative projects aimed at generating complex tissues for several parts of the body.

Tag: hydrogels

Highways to Health: Bicontinuous Structures Speed Up Cell Migration