Penn Bioengineer Develops 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, served as lead author of this new study. Ko conducted postdoctoral research at Massachusetts General Hospital (MGH) and the Wyss Institute at Harvard University, and the work for this study was done in collaboration with 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, Ko’s 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 enabled Ko to achieve 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).

Bioengineering Contributes to “New COVID-19 Testing Technology at Penn”

César de la Fuente, Ph.D., a Presidential Assistant Professor in Psychiatry, Microbiology, and Bioengineering, is leading a team to develop an electrode that can be easily printed at low cost to provide COVID-19 test results from your smart phone.

A recent Penn Medicine blog post surveys the efforts across Penn and the Perelman School of Medicine to develop novel says to detect SARS-CoV-2 and features several Department of Bioengineering faculty and Graduate Group members, including César de la Fuente, Presidential Assistant Professor in Psychiatry, Microbiology, and Bioengineering; Arupa Ganguly, Professor in Genetics; A.T. Charlie Johnson, Rebecca W. Bushnell Professor in Physics and Astronomy; Lyle Ungar, Professor in Computer and Information Science; and Ping Wang, Associate Professor in Pathology and Laboratory Medicine.

Read “We’ll Need More than Vaccines to Vanquish the Virus: New COVID-19 Testing Technology at Penn” by Melissa Moody in Penn Medicine News.

Hao Huang Named AIMBE Fellow

Hao Huang, Ph.D.

Hao Huang, Research Associate Professor of Radiology in the Perelman School of Medicine and member of the Penn Bioengineering Graduate Group, has been named an American Institute for Medical and Biological Engineering (AIMBE) Fellow.

Election to the AIMBE College of Fellows is among the highest professional distinctions accorded to a medical and biological engineer. “The College of Fellows is comprised of the top two percent of medical and biological engineers in the country. The most accomplished and distinguished engineering and medical school chairs, research directors, professors, innovators, and successful entrepreneurs comprise the College of Fellows. AIMBE Fellows are regularly recognized for their contributions in teaching, research, and innovation.”

Huang was “nominated, reviewed, and elected by peers and members of the College of Fellows for contributions to the development and applications of innovative MR methods to study the developing brain.”

A formal induction ceremony will be held during AIMBE’s virtual 2021 Annual Event on March 26. Huang will be inducted along with 174 colleagues who make up the AIMBE Fellow Class of 2021.

Read the full press release.

BE Seminar: “Deconstructing and Reconstructing Human Tissues” (Kelly Stevens)

Kelly Stevens, PhD

Speaker:  Kelly Stevens, Ph.D.
Assistant Professor, Department of Bioengineering and Department of Laboratory Medicine & Pathology
University of Washington

Date: Thursday, January 21, 2021
Time: 3:00-4:00 PM EST
Zoom – check email for link or contact ksas@seas.upenn.edu

Title: “Deconstructing and Reconstructing Human Tissues”

Abstract:

Although much progress has been made in building artificial human tissues over the past several decades, replicating complex tissue structure remains an enormous challenge. To overcome this challenge, our field first needs to create better three-dimensional spatial maps, or “blueprints” of human tissues and organs. We also need to then understand how these spatial blueprints encode positional processes in tissues. My group is developing new advanced biofabrication technologies to address both of these issues. Here, I will describe some of our work in both attaining transcriptomic maps as well as in controlling spatiogenetic wiring of human artificial tissues.

Bio:

Dr. Kelly Stevens is an Assistant Professor of Bioengineering, and Laboratory Medicine & Pathology at the University of Washington. Dr. Stevens’ research focuses on mapping and building artificial human tissues to treat liver and heart disease. She has made contributions to improve human cell sourcing, vascularization, structure and physiology of human bioartificial tissues. Dr. Stevens has received several awards in recognition of this work, including the NIH New Innovator Award, BMES CMBE Rising Star Award, John Tietze Stem Cell Scientist Award, and Gree Foundation Scholar Award.