Light-activated synthetic protein illuminates disease destruction

Illustration of collagen’s rope-like structure. Click to watch video. (INBT Animation Studios)

Johns Hopkins researchers have created a synthetic protein that, when activated by ultraviolet light, can guide doctors to places within the body where cancer, arthritis and other serious medical disorders can be detected. The synthetic protein does not zero in directly on the diseased cells. Instead, it binds to nearby collagen that has been degraded by disease or injury.

“These disease cells are like burglars who break into a house and do lots of damage but who are not there when the police arrive,” said S. Michael Yu, a faculty member in the Whiting School of Engineering’s Department of Materials Science and Engineering. “Instead of looking for the burglars, our synthetic protein is reacting to evidence left at the scene of the crime,” said Yu, who was principal investigator in the study.

The technique could lead to a new type of diagnostic imaging technology and may someday serve as a way to move medications to parts of the body where signs of disease have been found. In a study published in the Aug. 27-31 Online Early Edition of Proceedings of the National Academy of Sciences, the researchers reported success in using the synthetic protein in mouse models to locate prostate and pancreatic cancers, as well as to detect abnormal bone growth activity associated with Marfan syndrome.

Collagen, the body’s most abundant protein, provides structure and creates a sturdy framework upon which cells build nerves, bone and skin. Some buildup and degradation of collagen is normal, but disease cells such as cancer can send out enzymes that break down collagen at an accelerated pace. It is this excessive damage, caused by disease, that the new synthetic protein can detect, the researchers said.

A key collaborator was Martin Pomper, a School of Medicine professor of radiology and co-principal investigator of the Johns Hopkins Center of Cancer Nanotechnology Excellence. Pomper and Yu met as fellow affiliates of the Johns Hopkins Institute for NanoBioTechnology. “A major unmet medical need is for a better non-invasive characterization of disrupted collagen, which occurs in a wide variety of disorders,” Pomper said. “Michael has found what could be a very elegant and practical solution, which we are converting into a suite of imaging and potential agents for diagnosis and treatment.”

The synthetic proteins used in the study are called collagen mimetic peptides or CMPs. These tiny bits of protein are attracted to and physically bind to degraded strands of collagen, particularly those damaged by disease. Fluorescent tags are placed on each CMP so that it will show up when doctors scan tissue with fluorescent imaging equipment. The glowing areas indicate the location of damaged collagen that is likely to be associated with disease.

In developing the technique, the researchers faced a challenge because CMPs tend to bind with one another and form their own structures, similar to DNA, in a way that would cause them to ignore the disease-linked collagen targeted by the researchers.

To remedy this, the study’s lead author, Yang Li, synthesized CMPs that possess a chemical “cage” to keep the proteins from binding with one another. Just prior to entering the bloodstream to search for damaged collagen, a powerful ultraviolet light is used to “unlock” the cage and allow the CMPs to initiate their disease-tracking mission. Li is a doctoral student from the Department of Chemistry in the Krieger School of Arts and Sciences at Johns Hopkins. Yu, who holds a joint appointment in that department, is his doctoral adviser.

Yu’s team tested Li’s fluorescently tagged and caged peptides by injecting them into lab mice that possessed both prostate and pancreatic human cancer cells. Through a series of fluorescent images taken over four days, researchers tracked single strands of the synthetic protein spreading throughout the tumor sites via blood vessels and binding to collagen that had been damaged by cancer.

Similar in vivo tests showed that the CMP can target bones and cartilage that contain large amounts of degraded collagen. Therefore, the new protein could be used for diagnosis and treatment related to bone and cartilage damage.

Although the process is not well understood, the breakdown and rebuilding of collagen is thought to play a role in the excessive bone growth found in patients with Marfan syndrome. Yu’s team tested their CMPs on a mouse model for this disease and saw increased CMP binding in the ribs and spines of the Marfan mice, as compared to the control mice.

Funding for the research was provided by the National Science Foundation, the National Institutes of Health and the Department of Defense. The synthetic protein process used in this research is protected by patents obtained through the Johns Hopkins Technology Transfer Office.

Along with Yu, Li and Pomper, co-authors of this study were instructor Catherine A. Foss and medical resident Collin M. Torok from the Department of Radiology and Radiological Science at the Johns Hopkins School of Medicine; Harry C. Dietz, a professor, and Jefferson J. Doyle, a doctoral student, both of the Howard Hughes Medical Institute and Institute of Genetic Medicine at the School of Medicine; and Daniel D. Summerfield a former master’s student in the Department of Materials Science and Engineering.

Adapted from an original press release by Phil Sneiderman.

 

Meet INBT’s summer interns, already digging into their research

Research does not take a holiday during the summer at Johns Hopkins University in Baltimore, Md. In fact, it ramps up with the addition of many new faces from across the country.

The Johns Hopkins Institute for NanoBioTechnology summer research interns have arrived and are already busy at work in various laboratories. This year’s group is the largest the institute has ever hosted, with 17 undergraduates from universities nationwide.

Of the total, three students are affiliated with the Center of Cancer Nanotechnology Excellence and four are affiliated with the Physical Sciences-Oncology Center. The remaining 10 are part of the National Science Foundation Research Experience for Undergraduates program. All are hosted through INBT, which serves as a hub for their academic and social activities.

INBT summer interns conduct 10 weeks of research in a laboratory either on the Homewood or the medical campus of the University. At the end of that time, students have learned how to work in a multidisciplinary team and how to manage a short term research project.  They also discover if research is a pathway they want to pursue after earning their bachelor’s degrees.

In August, interns from many of the science, medicine, engineering and public health summer programs will gather for a  poster session to be held on August 2 at 3 p.m. in Turner Concourse. The poster session will allow students to show off the results of their their work.

This year’s INBT/PS-OC/CCNE interns include:

At the Whiting School of Engineering…

Amani Alkayyali from Wayne State University is an REU student in the laboratory of Honggang Cui assistant professor in the Department of Chemical and Biomolecular Engineering. Also in the Cui lab are CCNE intern Matthew Fong from the University of California, Berkeley and Michelle LaComb, an REU student from Rice University.

Sharon Gerecht, assistant professor in the Department of Chemical and Biomolecular engineering, is hosting three interns. Josh Porterfield of Cornell University and Carolyn Zhang from the University of California, San Diego are both PS-OC interns, and Bria Macklin of Howard University is an REU intern.

Jacqueline Carozza of Cornell University is a PS-OC student working in the lab of Denis Wirtz, professor in the Department Chemical and Biomolecular Engineering. Cassandra Loren from Oregon State University is a PS-OC intern also working in the Wirtz lab.

Eric Do from the University of Washington is an REU working in the lab of assistant professor Margarita Herrara-Alonso in the Department of Materials Science and Engineering.

Olivia Hentz from Cornell is an REU student working in the lab of Jonah Erlebacher, professor in the Department of Materials Science and Engineering.

Justin Samorajski from the University of Dallas is a returning summer intern, once again working in the materials science and engineering lab of professor Peter Searson as part of the CCNE.

At the School of Medicine…

Lauren Lee of Cornell University is an REU working in the lab of biomedical engineering lab of associate professor Hai-Quan Mao.

Albert Lu from the University of California Berkeley is a CCNE intern working in the biomedical engineering lab of associate professor Jeff Wang.

Bianca Lascano from Norfolk State University is an REU in assistant professor Jordan Green’s biomedical engineering lab.

Charlie Nusbaum of the Richard Stockton College is an REU intern in the radiation oncology lab of assistant professor Robert Ivkov.

At the Krieger School of Arts and Sciences…

Anthony Loder of Rowan University is an REU working in the biology lab of assistant professor Xin Chen.

Daniel McClelland is also REU from Bethany College works in the chemistry laboratory of professor Howard Fairbrother.

 

 

It’s a small world: Micro/nanotechnology in regenerative medicine and cancer

Sageeta Bhatia

Nanotechnology, regenerative medicine and cancer will be the topic of a special biomedical engineering seminar on March 6 at 3 p.m. in the Darner Conference Room, Ross Building, Room G007 at the Johns Hopkins School of Medicine. Speaker Sangeeta Bhatia, MD, PhD, director, of the Laboratory for Multiscale Regenerative Technologies at Massachusetts Institute of Technology will present “It’s a small world: Micro/Nanotechnology in Regenerative Medicine and Cancer. ” She will discuss the role of micro and nanotechnology for mimicking, monitoring and perturbing the tissue microenvironment.

“I will present our work on reconstructing normal liver microenvironments using microtechnology, biomaterials and induced pluripotent stem cells as well as our work on normalizing diseased cancer microenvironments using both inorganic and organic nano materials,” Bhatia noted in an announcement.  Bhatia is a professor of Health Sciences and Technology and professor of Electrical Engineering and Computer Science at MIT.

The talk is hosted by associate professor of Materials Science and Engineering and affiliated faculty member of the Institute for NanoBioTechnology Hai-Quan Mao. The event is free and open to the Johns Hopkins Community. Refreshments will be served.

 

 

Engineered hydrogel helps grow new, scar-free skin

In early testing, this hydrogel, developed by Johns Hopkins researchers, helped improve healing in third-degree burns. Photo by Will Kirk/HomewoodPhoto.jhu.edu

Johns Hopkins researchers have developed a jelly-like material and wound treatment method that, in early experiments on skin damaged by severe burns, appeared to regenerate healthy, scar-free tissue.

In the Dec. 12-16 online Early Edition of Proceedings of the National Academy of Sciences, the researchers reported their promising results from mouse tissue tests. The new treatment has not yet been tested on human patients. But the researchers say the procedure, which promotes the formation of new blood vessels and skin, including hair follicles, could lead to greatly improved healing for injured soldiers, home fire victims and other people with third-degree burns.

The treatment involved a simple wound dressing that included a specially designed hydrogel—a water-based, three-dimensional framework of polymers. This material was developed by researchers at Johns Hopkins’ Whiting School of Engineering, working with clinicians at the Johns Hopkins Bayview Medical Center Burn Center and the Department of Pathology at the university’s School of Medicine.

Third-degree burns typically destroy the top layers of skin down to the muscle. They require complex medical care and leave behind ugly scarring. But in the journal article, the Johns Hopkins team reported that their hydrogel method yielded better results. “This treatment promoted the development of new blood vessels and the regeneration of complex layers of skin, including hair follicles and the glands that produce skin oil,” said Sharon Gerecht, an assistant professor of chemical and biomolecular engineering who was principal investigator on the study.

Guoming Sun, left, a postdoctoral fellow, and Sharon Gerecht, an assistant professor of chemical and biomolecular engineering, helped develop a hydrogel that improved burn healing in early experiments. Photo by Will Kirk/HomewoodPhoto.jhu.edu

Gerecht said the hydrogel could form the basis of an inexpensive burn wound treatment that works better than currently available clinical therapies, adding that it would be easy to manufacture on a large scale. Gerecht suggested that because the hydrogel contains no drugs or biological components to make it work, the Food and Drug Administration would most likely classify it as a device. Further animal testing is planned before trials on human patients begin. But Gerecht said, “It could be approved for clinical use after just a few years of testing.”

John Harmon, a professor of surgery at the Johns Hopkins School of Medicine and director of surgical research at Bayview, described the mouse study results as “absolutely remarkable. We got complete skin regeneration, which never happens in typical burn wound treatment.”

If the treatment succeeds in human patients, it could address a serious form of injury. Harmon, a coauthor of the PNAS journal article, pointed out that 100,000 third-degree burns are treated in U. S. burn centers like Bayview every year. A burn wound dressing using the new hydrogel could have enormous potential for use in applications beyond common burns, including treatment of diabetic patients with foot ulcers, Harmon said.

Guoming Sun, Gerecht’s Maryland Stem Cell Research Postdoctoral Fellow and lead author on the paper, has been working with these hydrogels for the last three years, developing ways to improve the growth of blood vessels, a process called angiogenesis. “Our goal was to induce the growth of functional new blood vessels within the hydrogel to treat wounds and ischemic disease, which reduces blood flow to organs like the heart,” Sun said. “These tests on burn injuries just proved its potential.”

Gerecht says the hydrogel is constructed in such a way that it allows tissue regeneration and blood vessel formation to occur very quickly. “Inflammatory cells are able to easily penetrate and degrade the hydrogel, enabling blood vessels to fill in and support wound healing and the growth of new tissue,” she said. For burns, the faster this process occurs, Gerecht added, the less there is a chance for scarring.

Originally, her team intended to load the gel with stem cells and infuse it with growth factors to trigger and direct the tissue development. Instead, they tested the gel alone. “We were surprised to see such complete regeneration in the absence of any added biological signals,” Gerecht said.

Sun added, “Complete skin regeneration is desired for various wound injuries. With further fine-tuning of these kinds of biomaterial frameworks, we may restore normal skin structures for other injuries such as skin ulcers.”

Gerecht and Harmon say they don’t fully understand how the hydrogel dressing is working. After it is applied, the tissue progresses through the various stages of wound repair, Gerecht said. After 21 days, the gel has been harmlessly absorbed, and the tissue continues to return to the appearance of normal skin.

The hydrogel is mainly made of water with dissolved dextran—a polysaccharide (sugar molecule chains). “It also could be that the physical structure of the hydrogel guides the repair,” Gerecht said. Harmon speculates that the hydrogel may recruit circulating bone marrow stem cells in the bloodstream. Stem cells are special cells that can grow into practically any sort of tissue if provided with the right chemical cue. “It’s possible the gel is somehow signaling the stem cells to become new skin and blood vessels,” Harmon said.

Additional co-authors of the study included Charles Steenbergen, a professor in the Department of Pathology; Karen Fox-Talbot, a senior research specialist from the Johns Hopkins School of Medicine; and physician researchers Xianjie Zhang, Raul Sebastian and Maura Reinblatt from the Department of Surgery and Hendrix Burn and Wound Lab. From the Whiting School’s Department of Chemical and Biomolecular Engineering, other co-authors were doctoral students Yu-I (Tom) Shen and Laura Dickinson, who is a Johns Hopkins Institute for NanoBioTechnology (INBT) National Science Foundation IGERT fellow. Gerecht is an affiliated faculty member of INBT.

The work was funded in part by the Maryland Stem Cell Research Fund Exploratory Grant and Postdoctoral Fellowship and the National Institutes of Health.

The Johns Hopkins Technology Transfer staff has filed a provisional patent application to protect the intellectual property involved in this project.

Related links:

Sharon Gerecht’s Lab

Johns Hopkins Burn Center

Johns Hopkins Institute for NanoBioTechnology

 

Story by Mary Spiro

Engineers put a new ‘twist’ on lab-on-a-chip

Close-up of a cylindrically-shaped microfluidic device with two fluorescent solutions flowing through. Reproduced with permission from Nature Communications.

A leaf works something like a miniature laboratory. While the pores on the leaf surface allow it to channel nutrients in and waste products away from a plant, part of a leaf’s function also lies in its ability to curl and twist. Engineers use polymers to create their own mini-labs, devices called “labs-on-a-chip,” which have numerous applications in science, engineering and medicine. The typical flat, lab on a chip, or microfluidic device, resembles an etched microscopy cover slip with channels and grooves.

But what if you could get that flat lab-on-a-chip to self-assemble into a curve, mimicking the curl, twist or spiral of a leaf? Mustapha Jamal, a PhD student and IGERT fellow from Johns Hopkins Institute for NanoBioTechnology, has created a way to make that so.

Jamal is the lead author on “Differentially photo-crosslinked polymers enable self-assembling microfluidics,” published November 8, 2011 in Nature Communications. Along with principle investigator David Gracias, associate professor of Chemical and Biomolecular Engineering in the Whiting School of Engineering, and fellow graduate student Aasiyeh Zarafshar, Jamal has developed, for the first time, a method for creating three-dimensional lab-on-a-chip devices that can curl and twist.

The process involves shining ultraviolet (UV) light on a film of a substance called SU-8. Film areas closer to the light source become more heavily crosslinked than layers beneath, which on solvent conditioning creates a stress gradient.

Immersing the film in water causes the film to curl. Immersion in organic solvents like acetone causes the film to flatten. The curling and flattening can be reversed. The result, Jamal said, is the “self-assembly of intricate 3D devices that contain microfluidic channels.” This simple method, he added, can “program 2D polymeric (SU-8) films such that they spontaneously and reversibly curve into intricate 3D geometries including cylinders, cubes and corrugated sheets.”

Members of the Gracias lab have previously created curving and folding polymeric films consisting of two different materials. This new method achieves a stress gradient along the thickness of a single substance. “This provides considerable flexibility in the type and extent of curvature that can be created by varying the intensity and direction of exposure to UV light,” Gracias said.

Gracias explained that the method works with current protocols and materials for fabricating flat microfluidic devices. For example, one can design a 2D film with one type of lab-on-a-chip network, and then use their method to shape it into another geometry, also with microfluidic properties.

Fluorescent image of curved, self-assembled microfluidic device. Reproduced with permission from Nature Communications.

“Since our approach is compatible with planar lithography methods, we can also incorporate optical elements such as split ring resonators that have unique optical features. Alternatively, flexible electronic circuits could be incorporated and channels could be used to transport cooling fluids” Gracias said.

Tissue engineering is among the many important applications for 3D microfluidic devices, Gracias said. “Since many hydrogels can be photopolymerized, we can use the methodology of differential cross-linking to create stress gradients in these materials,” Gracias explained. “We plan to create biodegradable, vascularized tissue scaffolds using this approach.”

Link to the journal article here.

Story by Mary Spiro

 

 

Panel discussion tackles the question: Is undergraduate research for you?

Undergraduates presenting at summer research symposium.

Are you an undergraduate  engineering student who wants to do research but just doesn’t know where to start?

The Johns Hopkins chapter of the Society of Women Engineers  will host a panel discussion Thursday, October 27 at 7 PM in room 132 of Gilman Hall  on the Homewood campus.  The panel discussion is designed to answer your questions about getting started in research at Johns Hopkins University.   Listen to a panel of undergraduate research students in engineering discuss what it’s like to work in an engineering lab.

Undergraduate research experience is extremely important if you want to apply for internships, jobs, scholarships and postgraduate work. Conducting research while you’re an undergraduate also helps put this ideas that you’ve learned in class into action for larger goal. Some undergraduate researchers  even have their work published in peer-reviewed journals.

Johns Hopkins Institute for NanoBiotechnology offers a summer research experience for undergraduates in nano bio.   A criteria for applying to an REU  program is that you have had prior research experience.  Don’t miss your opportunity to learn about this exciting component of your undergraduate academic career.

For more information about the Society of Women Engineers go to http://www.jhu.edu/swe/index.html

For details about  about Johns Hopkins Institute for Nano Biotechnology summer Research Experience for Undergraduates program, go to http://inbt.jhu.edu/education/undergraduate/reu/

Applications for the 2012 summer program will be accepted soon.

Agenda set for Oct. 10 mini-symposium on cancer, nanotech

From the spring mini-symposium.

Johns Hopkins Physical Sciences-Oncology Center and Center of Cancer Nanotechnology Excellence will host a mini-symposium on Monday Oct., 10 in the Hackerman Hall Auditorium. Talks on topics related to cancer and nanotechnology begin at 9 a.m.

Speakers include:

  • 9:15 a.m.: The pulsating motion of breast cancer cell is regulated by surrounding epithelial cells. Speaker: Meng Horng Lee
  • 9:40 a.m.: Breast tumor extracellular matrix promotes vasculogenesis. Speaker: Abigail Hielscher
  • 10:00 a.m.: Attachment to growth substrate regulates expression of GDF15, an important molecule in metastatic cancer. Speaker: Koh Meng Aw Yong
  • 10:20 a.m.: Mucin 16 is a functional selectin ligand on pancreatic cancer cells. Speaker: Jack Chen
  • 10:40 a.m.: Particle tracking in vivo. Speaker: Pei-Hsun Wu

These talks are open to the entire Hopkins community. No RSVP is required. Refreshments will be served.

 

 

Hopkins Imaging Initiative to host first annual conference

The Johns Hopkins University Imaging Initiative will host the first annual Imaging Conference, October 6, 2011 at the Turner Auditorium on the medical campus. The conference features afternoon lectures from various Hopkins faculty followed by a research poster session and happy hour. Anyone interested in imaging is welcome to attend.

Speakers include Elliot McVeigh, director of the Department of Biomedical Engineering; Elliot Fishman, MD, director of diagnostic imaging at body CT at Johns Hopkins Hospital; Jerry Prince, the William B. Kouwenhoven Professor of Electrical and Computer Engineering at the Whiting School of Engineering; Xingde Li, associate professor of biomedical engineering and head of the Laboratory of Biophotonics Imaging and Therapy at the Whiting School; Peter van Zijl, professor of radiology at the school of medicine and director of the F.M. Kirby Research Center for Functional Brain Imaging; and several others to be announced.

Abstracts will be accepted until Sept 6 and conference registration will be accepted until October 1. For complete information about this event and to register, go to http://imaging.jhu.edu/conferences/imaging-conference-2011

 

 

 

 

Money makes the (research) world go ‘round

Photo Illustration by Mary Spiro.

Grant money drives research, but obtaining funding can be a daunting task for those unfamiliar with the process. Wouldn’t it be nice to have someone to show you the ropes?

That’s why three postdoctoral fellows from Johns Hopkins Institute for NanoBioTechnology were asked to present a sort of crash course in how to get those almighty research dollars. The talk, given as one of INBT’s professional development seminars on July 27 to a group of graduate, undergraduate and a few high school summer research interns, covered basics, as well as some commonly overlooked issues encountered in the grant application process.

“When applying for grant funds you have to assume that everyone else also has a good idea. Your idea has to be better than great; it has to be outstanding,” Eric Balzer told attendees. Balzer is a postdoctoral fellow with professor Konstantinos Konstantopoulos in the department of Chemical and Biomolecular Engineering.

He also advised the group to avoid novice grant writing errors such as “submitting a proposal on lung cancer to an agency that only funds breast cancer research.” In other words, read the funding agency’s mission statement.

Yanique Rattigan stressed the importance of avoiding overly complex language in grant applications. “Grant reviewers often include patient representatives who are not scientists and engineers, so you have to make sure that there is a section describing the research in lay terms that they can understand,” offered Rattigan, who is conducting research in the pathology lab of professor Anirban Maitra at the Johns Hopkins School of Medicine.

Granting agencies look to fund novel research ideas, explained Daniele Gilkes. “They want to know how your work will fill in the knowledge gaps that exist in the field. You can determine this through thorough analysis of the current literature pertinent to your area of research,” added Gilkes, who works with Denis Wirtz, the Smoot Professor of Engineering in the Department of Chemical and Bimolecular Engineering.”

The group stressed the need to edit and re-edit a grant application prior to submission, and emphasized the importance of choosing the right referee to compose letters that truly support the candidates potential for independent research.

The teams’ insight into the grant application process can be found in this SlideShare slide show, click here.

Story by Mary Spiro.

 

 

 

 

 

 

 

 

 

 

 

 

Collagen video scores high in magazines reader’s choice vote

Screen capture from INBT’s video on collagen mimetic peptides.

The Scientist magazine has announced its annual Multimedia Awards—the Labbys—and Johns Hopkins Institute for NanoBioTechnology’s video on collagen mimetic peptides has been selected as a finalist. According to the voting, we are a strong second in the race. It appears voting is continuing well past the original June 30 deadline. So keep voting!

Help choose us as the top science video by going to this website (http://the-scientist.com/2011/06/15/2011-labby-video-finalists/#vote)  and selecting “Mimicking Collagen.” The video features Michael Yu, associate professor of materials science and engineering and some fantastic animations and illustration from INBT’s Animation studio. Animations in the video were created by Ella McCrea, a graduate from the Maryland Institute College of Art, and Nathan Weiss, a masters graduate from Johns Hopkins University.

Winners of the reader’s choice will be announced in the magazine and online in September. Top picks will also be chosen by The Scientist’s panel of judges, which includes the father of the infographic Nigel Holmes, Kirsten Sanford of the Science Channel (aka Dr. KiKi), Jeffrey Segall of the Albert Einstein College of Medicine in New York City, and David Kirby of the University of Manchester.

You can only vote once, so share this link with your friends.