DNA nanotubes self-assemble into molecular bridges between cells

In a microscopic feat that resembled a high-wire circus act, Johns Hopkins researchers have coaxed DNA nanotubes to assemble themselves into bridge-like structures arched between two molecular landmarks on the surface of a lab dish. This self-assembling bridge process, which may someday be used to connect electronic medical devices to living cells, was reported by the team recently in the journal Nature Nanotechnology.

Assistant Prof. Rebecca Schulman, left, and postdoctoral fellow Abdul Mohammed used this single-molecule fluorescence microscope to track the nanotube bridge formation process. Photo by Will Kirk/Johns Hopkins University.

Assistant Prof. Rebecca Schulman, left, and postdoctoral fellow Abdul Mohammed used this single-molecule fluorescence microscope to track the nanotube bridge formation process. Photo by Will Kirk/Johns Hopkins University.

The ability to assemble these bridges, the researchers say, suggests a new way to build medical devices that use wires, channels or other devices that could “plug in” to molecules on a cell’s surface. Such technologies could be used to understand nerve cell communication or to deliver therapeutics with unprecedented precision. Molecular bridge-building, the researchers said, is also a step toward building networked devices and “cities” at the nanoscale, enabling new components of a machine or factory to communicate with one another.

To describe this process, senior author Rebecca Schulman, an assistant professor of chemical and biomolecular engineering in the Whiting School of Engineering and an INBT affiliated faculty member, referred to a death-defying stunt shown in the movie “Man on Wire.” The film depicted Philippe Petit’s 1974 high-wire walk between the World Trade Center’s Twin Towers.

Schulman and postdoctoral fellow Abdul Mohammed used a single-molecule fluorescence microscope to track the nanotube bridge formation process. These building blocks attached themselves to separate molecular anchor posts, representing where the connecting bridge would begin and end. The segments formed two nanotube chains, each one extending away from its anchor post. Then, like spaghetti in a pot of boiling water, the lengthening nanotube chains wriggled about, exploring their surroundings in a random fashion. Eventually, this movement allowed the ends of the two separate nanotube strands to make contact with one another and snap together to form a single connecting bridge span. This process can be seen in this video, linked here. Read the entire Johns Hopkins press release here.

 

 

 

Apply now to conduct research in Belgium

Are you an undergraduate student at Johns Hopkins in a science or engineering major who wants to study abroad? Johns Hopkins Institute for NanoBioTechnology (INBT) is currently accepting applications for the International Research Experience for Students (IRES) internship at the Inter-University MicroElectronics Centre (IMEC), in Leuven, Belgium. Applications are due January 23, 2017.

To apply, send the following application materials to Tom Fekete at tfekete1@jhu.edu and copy Camille Mathis at cmathis@jhu.edu:
• Industry-style resume
• Research statement
• One professional letter of reference

Each year since 2009, INBT has sent a group of students to Belgium to conduct research. Read more about the IRES program here and read blog posts from former INBT IRES participants here.

If you have additional questions or for more information on the application process, please contact Tom Fekete, INBT director of corporate partnerships, at tfekete1@jhu.edu.

23914748696_50091866d2_z

 

Combo treatment harnesses immune system to fight skin cancer

By combining two treatment strategies, both aimed at boosting the immune system’s killer T cells, Johns Hopkins researchers report they lengthened the lives of mice with skin cancer more than by using either strategy on its own. And, they say, because the combination technique is easily tailored to different types of cancer, their findings — if confirmed in humans — have the potential to enhance treatment options for a wide variety of cancer patients.

“To our knowledge, this was the first time a ‘biomimetic,’ artificial, cell-like particle — engineered to mimic an immune process that occurs in nature — was used in combination with more traditional immunotherapy,” says Jonathan Schneck, M.D., Ph.D., professor of pathology, who led the study together with Jordan Green, Ph.D., associate professor of biomedical engineering, both of whom are also members of the Kimmel Cancer Center and the Institute for NanoBioTechnology.

A summary of their study results will be published in the February issue of the journal Biomaterials.

Scientists know the immune system is a double-edged sword. If it’s too weak, people succumb to viruses, bacteria and cancer; if it’s too strong, they get allergies and autoimmune diseases, like diabetes and lupus. To prevent the immune system’s killer T cells from attacking them, the body’s own cells display the protein PD-L1, which “shakes hands” with the protein PD-1 on T cells to signal they are friend, not foe.

Unfortunately, many cancer cells learn this handshake and display PD-L1 to protect themselves. Once scientists and drugmakers figured this out, cancer specialists began giving their patients a recently developed class of immunotherapy drugs including a protein, called anti-PD-1, a so-called checkpoint inhibitor, that blocks PD-1 and prevents the handshake from taking place.

Screen Shot 2016-12-21 at 11.53.42 AM

(Alyssa Kosmides and Randall Meyer, Johns Hopkins Medicine) This immunotherapy technique combines artificial antigen presenting cells (orange) with anti-PD-1 antibodies (yellow) to activate killer T cells (pink) and prevent tumor cells (brown) from damping that response. « Dual Strategy Teaches Mouse Immune Cells to Overcome Cancer’s Evasive Techniques

PD-1 blockers have been shown to extend cancer survival rates up to five years but only work for a limited number of patients: between 15 to 30 percent of patients with certain types of cancer, such as skin, kidney and lung cancer. “We need to do better,” says Schneck, who is also a member of the Institute for Cell Engineering.

For the past several years, Schneck says, he and Green worked on an immune system therapy involving specialized plastic beads that showed promise treating skin cancer, or melanoma, in mice. They asked themselves if a combination of anti-PD1 and their so-called biomimetic beads could indeed do better.

Made from a biodegradable plastic that has been FDA-approved for other applications and outfitted with the right proteins, the tiny beads interact with killer T cells as so-called antigen-presenting cells (APCs), whose job is to “teach” T cells what threats to attack. One of the APC proteins is like an empty claw, ready to clasp enemy proteins. When an untrained T cell engages with an APC’s full claw, that T cell multiplies to swarm the enemy identified by the protein in the claw, Schneck explains.

“By simply bathing artificial APCs in one enemy protein or another, we can prepare them to activate T cells to fight specific cancers or other diseases,” says Green.

To test their idea for a combined therapy, the scientists first “primed” T cells and tumor cells to mimic a natural tumor scenario, but in a laboratory setting. In one tube, the scientists activated mouse T cells with artificial APCs displaying a melanoma protein. In another tube, they mixed mouse melanoma cells with a molecule made by T cells so they would ready their PD-L1 defense. Then the scientists mixed the primed T cells with primed tumor cells in three different ways: with artificial APCs, with anti-PD-1 and with both.

To assess the level of T cell activation, they measured production levels of an immunologic molecule called interferon-gamma. T cells participating in the combined therapy produced a 35 percent increase in interferon-gamma over the artificial APCs alone and a 72 percent increase over anti-PD-1 alone.

The researchers next used artificial APCs loaded with a fluorescent dye to see where the artificial APCs would migrate after being injected into the bloodstream. They injected some mice with just APCs and others with APCs first mixed with T cells.

The following day, they found that most of the artificial APCs had migrated directly to the spleen and liver, which was expected because the liver is a major clearing house for the body, while the spleen is a central part of the immune system. The researchers also found that 60 percent more artificial APCs found their way to the spleen if first mixed with T cells, suggesting that the T cells helped them get to the right spot.

Finally, mice with melanoma were given injections of tumor-specific T cells together with anti-PD-1 alone, artificial APCs alone or anti-PD-1 plus artificial APCs. By tracking blood samples and tumor size, the researchers found that the T cells multiplied at least twice as much in the combination therapy group than with either single treatment. More importantly, they reported, the tumors were about 30 percent smaller in the combination group than in mice that received no treatment. The mice also survived longest in the combination group, with 45 percent still alive at day 20, when all the mice in the other groups were dead.

“This was a great indication that our efforts at immunoengineering, or designing new biotechnology to tune the immune system, can work therapeutically,” says Green. “We are now evaluating this dual strategy utilizing artificial APCs that further mimic the shapes of immune cells, such as with football and pancake shapes based on our previous work, and we expect those to do even better.”

Other authors of the report include Alyssa Kosmides, Randall Meyer, and John Hickey (all of who are INBT training grant students) as well as Kent Aje and Ka Ho Nicholas Cheung of the Johns Hopkins University School of Medicine.

This work was supported in part by grants from the National Institute of Allergy and Infectious Diseases (AI072677, AI44129), the National Cancer Institute (CA108835, R25CA153952, 2T32CA153952-06, F31CA206344), the National Institute of Biomedical Imaging and Bioengineering (R01-EB016721), the Troper Wojcicki Foundation, the Bloomberg~Kimmel Institute for Cancer Immunotherapy at Johns Hopkins, the JHU-Coulter Translational Partnership, the JHU Catalyst and Discovery awards programs, the TEDCO Maryland Innovation Initiative, the Achievement Rewards for College Scientists, the National Science Foundation (DGE-1232825), and sponsored research agreements with Miltenyi Biotec and NexImmune.

Under a licensing agreement between NexImmune and The Johns Hopkins University, Jonathan Schneck is entitled to a share of royalty received by the university on sales of products derived from this article. Jordan Green is on the scientific advisory board for NexImmune. The terms of these arrangements are being managed by The Johns Hopkins University in accordance with its conflict of interest policies.

Read more about the Jordan Green Group here.

Read more about the Jonathan Schneck Lab here.

Read more about NexImmune here.

SOURCE: Johns Hopkins School of Medicine

Betenbaugh research seeks better control of antibody production

Antibodies are blood proteins created by the immune system in response to a certain antigen. Antibodies have become the chief component in myriad medicine applications from diagnostic tests to several widely used pharmaceuticals for the treatment of asthma, arthritis, cancer and more.

How handy would it be to be able control the function of the antibodies made in a lab, simply by tweaking the nutrient media that you used to grown them in? And how useful would it be, if you could increase the quantity of antibodies produced, also be modifying the media in which they were created?

1280px-Catumaxomab_mechanism.svg

Bound for destruction: Y-shapted antibody binds t-cell and macrophage to tumor cell.

Pharmaceutical manufacturers seek more efficient ways to grow genetically engineered human antibodies on a large scale. Through a partnership with MedImmune, researchers in the laboratory of Michael Betenbaugh are taking an engineering approach to the solution. Betenbaugh, professor of Chemical and Biomolecular Engineering and an affiliate of Johns Hopkins INBT, seeks to discover ways to improve the growth media for the antibody-producing microbes. Their lab is not only looking at more efficient ways to grow large quantities of antibodies via microbes but also to find out if the properties of the antibodies can be influenced by the properties of the media in which the microbes are grown.

To read more about this research and the partnership with MedImmune, visit this link.

http://ventures.jhu.edu/johns-hopkins-medimmune-partnership-examines-antibody-production-house-looks-to-make-it-more-efficient/

MedImmune drug delivery expert to talk

Johns Hopkins Institute for NanoBioTechnology hosts Anand Subramony of MedImmune, who will present a one-house lecture/seminar on Friday, November 18 at 10:30 a.m. in the Great Hall in Levering Hall on the Homewood campus. Subramony is  Vice President for Drug Delivery and Device Development at MedImmune and will discuss the development of novel patient centric injection devices and novel drug delivery technologies for local delivery.

Dr. Sumbramony is an expert in materials science for drug delivery. He earned his PhD in Chemistry, Solid State Materials Science from Purdue University.  He has worked as a principal scientist for Johnson & Johnson and was the principal fellow and head of novel drug delivery technologies and therapeutics at Novartis Institutes for Biomedical Research, Inc. His research goals include developing next generation platform drug delivery devices for patient centric delivery of monoclonal antibodies, proteins, and peptides.

Anand Subramony of MedImmune

Anand Subramony of MedImmune

anand

The talk is free and open to the entire Johns Hopkins community. RSVP to Camille Mathis by emailing her at cmathis@jhu.edu.

 

Undergraduate symposium showcases multidisciplinary research

Undergraduate students affiliated with Johns Hopkins Institute for NanoBioTechnology (INBT) laboratories hosted their annual research symposium on Nov 10 at the Homewood campus. Five students gave oral presentations and 30 students presented posters during the half-day event designed to showcase multidisciplinary work from across INBT affiliated laboratories.

Winners Allie Zito, Joey Li and Hayley Strasburger

Symposium winners Allie Zito, Joey Li and Hayley Strasburger.

Talks were given during the first part of the symposium. Oral presenters included Damian Cross and Aseem Jain, who shared a talk about Perileve: A novel method for refractory ascites; James Shamul, who spoke about a Novel Micellar Drug Delivery System using Poly (Beta-amino ester)-Poly (ethylene glycol) copolymer; Michael Pozin, who presented Heat Transfer Modeling for Femoroplasty Procedure; and Hayley Strasburger, who described how Noggin inhibits bmp signaling in oligodendrocytes progenitor cells to repress trans-differentiation into astrocytes.

During the second half of the symposium, poster presenters talked to volunteer judges comprised of INBT staff and alumni. There were three poster categories: concept, overall and crowd favorite. While the volunteer judges evaluated the first two groups, crowd favorite was voted on by every attendee by texting a poster number to a certain phone number. Winners included in the Concept category Victor Tang (1st) and Allie Zito (2nd). In the overall category, Hayley Strasburger (1st) and Joey Li (2nd) were the inners. Allie Zito also won crowd favorite.

15000596_10154704353192277_9071690777271476868_oThe event was funded by the Office of the Provost and given organizational support by INBT. Thanks and acknowledgement to everyone who came out to the symposium, to the judges who took time away from their work to provide feedback, the Office of the Provost for funding the event and to INBT, especially Camille Mathis, Ellie Boettinger-Heasley, Tom Fekete, and Gregg Nass.

 

 

 

15000732_10154704352202277_8373453166163285809_o

Undergraduate symposium showcases ‘frontiers in medicine’

Johns Hopkins Institute for Nanobiotechnollgy’s Undergraduate Research Symposium, presented by the INBT Undergraduate Research Leadership, is scheduled for Thursday, November 10 from noon to 5 p.m. in the Glass Pavilion on the Homewood campus. The theme of the symposium is Frontiers in Medicine: Biological and Engineering Research. The event features invited student speaker talks, a poster session, an awards ceremony and light lunch.

Student Talks include the following: James Shamul, “Novel Micellar Drug Delivery System Using Poly(β-amino ester)–Poly(ethylene glycol) Copolymer;” Damian Cross, “Perileve: A Novel Management Method for Refractory Ascites;”Hayley Strasburger, “Noggin inhibits bmp signaling in oligodendrocyte progenitor cells to repress transdifferentiation into astrocytes; and Michael Pozin, “Heat Transfer Modeling for Femoroplasty Procedure.”

Please direct any questions to inbt.undergrads@gmail.com.

13091930_553937484814832_2524163206956623228_n

INBT’S undergraduate research symposium is Nov 10 in the Glass Pavilion

Agenda

12:00 pm: Check in
12:45 pm: Welcome
1:00 pm: Student Talks
2:00 pm: 1st Poster Session
3:15 pm: 2nd Poster Session
4:30 pm: Awards

 

 

A

Nanofiber technology rebuilds soft tissue damage

Patients with soft tissue damage will experience dramatic improvements with LifeSprout Tissue Regenerative Matrix (TRM). Hai-Quan Mao (Professor, MSE/INBT ChemBE), collaborating with Johns Hopkins School of Medicine faculty specialists Justin Sacks and Sashank Reddy, developed the technology that combines a tissue-plumping hydrogel with a cell-supporting nanofiber framework. Resulting tissue repairs are individualized and have a reduced chance of scarring, as well as being scar and inflammation free. The Louis B. Thalheimer Funds grant, among other funds, will help move LifeSprout TRM from prototype to pre-clinical testing and FDA approval.

 Nanofibers expand to fill the space left behind by tissue damage.

Nanofibers expand to fill the space left behind by tissue damage.

Often it takes years to bring a new technology through the approval process from bench top to bedside. However, because this technology uses materials that have been previously approved by the FDA, the time to clinical use should be shortened.

Watch this video by Johns Hopkins video storyteller Renee Fischer on LifeSprout Tissue Regenerative Matrix. Read more about the technology here on the Rising To the Challenge website.

Cell Dynamics in Health and Disease symposium

Screen Shot 2016-10-25 at 5.38.43 PMThe Institute for Basic Biomedical Sciences, Center for Cell Dynamics at the Johns Hopkins School of Medicine presents the symposium “Cell Dynamics in Health and Disease” on Thursday, November 17 from 9 a.m. to 5:30 p.m. in the Mountcastle Auditorium located in the Preclinical Teaching Building, 725 N. Wolfe Street on the medical campus.  The program includes invited faculty and guest expert speakers followed by a wine and cheese poster session.

The full agenda, which includes speakers from Harvard Medical School, UC-San Francisco, New York University, University of Pennsylvania, as well as Johns Hopkins University School of Medicine, can be viewed here.

Highlighted talks include the following:

  • 9:20 AM Opening Keynote Speaker
    “Physiology and Pharmacology of Microtubule Dynamics”
    Tim Mitchison, PhD
    Hasib Sabbagh Professor of Systems Biology
    Harvard Medical School
  • 10:45 AM “Regulation of RNA granule dynamics by intrinsically disordered proteins”
    Geraldine Seydoux, PhD
    Sheldon Professor in Medical Discover
    Department of Molecular Biology and Genetics
    Johns Hopkins University School of Medicine
  • 11:15 AM “Reverse Engineering Polarity Network Wiring”
    Lani Wu, PhD
    Professor
    Department of Pharmaceutical Chemistry
    University California, San Francisco
  • 11:45 AM “Toward Total Synthesis of Cell Function and Its Biomedical Applications”
    Takanari Inoue, PhD
    Associate Professor
    Department of Pharmacology and Molecular Sciences
    Department of Biological Chemistry and Biomedical Engineering
    Center for Cell Dynamics
    Johns Hopkins University School of Medicine
  • 1:15 PM “Microtubule Mechanics in the Beating Heart”
    Ben Prosser, PhD
    Assistant Professor
    Department of Physiology
    University of Pennsylvania
  • 1:45 PM “How Cells Count: Molecular Control of Centriole Duplication”
    Andrew Holland, PhD
    Assistant Professor
    Department of Molecular Biology and Genetics
    Johns Hopkins University School of Medicine
  • 2:15 PM “Cellular and Molecular Forces That Drive Metastases”
    Andrew Ewald, PhD
    Associate Professor
    Department of Cell Biology
    Center for Cell Dynamics
    Johns Hopkins University School of Medicine
  • 3:15 PM Closing Keynote Speaker
    “Forming the Next Generation”
    Ruth Lehman, PhDAkshay
    Director
    Skirball Institute
    Professor
    Department of Cell Biology
    New York University

Registration is required at this link and early registrants receive a souvenir Center for Cell Dynamics t-shirt, while supplies last. Poster submissions may also be submitted on the registration form. The t-shirt design is shown here!

Nanofiber coating prevents infections on prosthetic joints

One challenge with surgical implants is the risk of bacterial infection. Now researchers from Johns Hopkins Institute for NanoBioTechnology and the Johns Hopkins School of Medicine have developed a nano fiber coating that may help solve this problem. 

READ MORE FROM THE SCHOOL OF MEDICINE PRESS RELEASE BELOW.

unnamed-3

A titanium implant (blue) without a nanofiber coating in the femur of a mouse. Bacteria are shown in red and responding immune cells in yellow. Credit: Lloyd Miller/Johns Hopkins Medicine

In a proof-of-concept study on mice, scientists at The Johns Hopkins University show that a novel coating they made with antibiotic-releasing nanofibers has the potential to better prevent at least some serious bacterial infections related to total joint replacement surgery.

A report on the study, published online the week of Oct. 24 in Proceedings of the National Academy of Sciences, was conducted on the rodents’ knee joints, but, the researchers say, the technology would have “broad applicability” in the use of orthopaedic prostheses, such as hip and knee total joint replacements, as well pacemakers, stents and other implantable medical devices. In contrast to other coatings in development, the researchers report the new material can release multiple antibiotics in a strategically timed way for an optimal effect.

“We can potentially coat any metallic implant that we put into patients, from prosthetic joints, rods, screws and plates to pacemakers, implantable defibrillators and dental hardware,” says co-senior study author Lloyd S. Miller, M.D., Ph.D., an associate professor of dermatology and orthopaedic surgery at the Johns Hopkins University School of Medicine.

Surgeons and biomedical engineers have for years looked for better ways —including antibiotic coatings — to reduce the risk of infections that are a known complication of implanting artificial hip, knee and shoulder joints.

Every year in the U.S., an estimated 1 to 2 percent of the more than 1 million hip and knee replacement surgeries are followed by infections linked to the formation of biofilms — layers of bacteria that adhere to a surface, forming a dense, impenetrable matrix of proteins, sugars and DNA. Immediately after surgery, an acute infection causes swelling and redness that can often be treated with intravenous antibiotics. But in some people, low-grade chronic infections can last for months, causing bone loss that leads to implant loosening and ultimately failure of the new prosthesis. These infections are very difficult to treat and, in many cases of chronic infection, prostheses must be removed and patients placed on long courses of antibiotics before a new prosthesis can be implanted. The cost per patient often exceeds $100,000 to treat a biofilm-associated prosthesis infection, Miller says.

Major downsides to existing options for local antibiotic delivery, such as antibiotic-loaded cement, beads, spacers or powder, during the implantation of medical devices are that they can typically only deliver one antibiotic at a time and the release rate is not well-controlled. To develop a better approach that addresses those problems, Miller teamed up with Hai-Quan Mao, Ph.D., a professor of materials science and engineering at the Johns Hopkins University Whiting School of Engineering, and a member of the Institute for NanoBioTechnology, Whitaker Biomedical Engineering Institute and Translational Tissue Engineering Center.

Over three years, the team focused on designing a thin, biodegradable plastic coating that could release multiple antibiotics at desired rates. This coating is composed of a nanofiber mesh embedded in a thin film; both components are made of polymers used for degradable sutures.

To test the technology’s ability to prevent infection, the researchers loaded the nanofiber coating with the antibiotic rifampin in combination with one of three other antibiotics: vancomycin, daptomycin or linezolid. “Rifampin has excellent anti-biofilm activity but cannot be used alone because bacteria would rapidly develop resistance,” says Miller. The coatings released vancomycin, daptomycin or linezolid for seven to 14 days and rifampin over three to five days. “We were able to deploy two antibiotics against potential infection while ensuring rifampin was never present as a single agent,” Miller says.

The team then used each combination to coat titanium Kirschner wires — a type of pin used in orthopaedic surgery to fix bone in place after wrist fractures — inserted them into the knee joints of anesthetized mice and introduced a strain of Staphylococcus aureus, a bacterium that commonly causes biofilm-associated infections in orthopaedic surgeries. The bacteria were engineered to give off light, allowing the researchers to noninvasively track infection over time.

Miller says that after 14 days of infection in mice that received an antibiotic-free coating on the pins, all of the mice had abundant bacteria in the infected tissue around the knee joint, and 80 percent had bacteria on the surface of the implant. In contrast, after the same time period in mice that received pins with either linezolid-rifampin or daptomycin-rifampin coating, none of the mice had detectable bacteria either on the implants or in the surrounding tissue.

“We were able to completely eradicate infection with this coating,” says Miller. “Most other approaches only decrease the number of bacteria but don’t generally or reliably prevent infections.”

After the two-week test, each of the rodents’ joints and adjacent bones were removed for further study. Miller and Mao found that not only had infection been prevented, but the bone loss often seen near infected joints — which creates the prosthetic loosening in patients — had also been completely avoided in animals that received pins with the antibiotic-loaded coating.

Miller emphasized that further research is needed to test the efficacy and safety of the coating in humans, and in sorting out which patients would best benefit from the coating — people with a previous prosthesis joint infection receiving a new replacement joint, for example.

The polymers they used to generate the nanofiber coating have already been used in many approved devices by the U.S. Food and Drug Administration, such as degradable sutures, bone plates and drug delivery systems.

In addition to Miller and Mao, the study’s authors are Alyssa Ashbaugh, Xuesong Jiang, Jesse Zheng, Andrew Tsai, Woo-Shin Kim, John Thompson, Robert Miller, Jonathan Shahbazian, Yu Wang, Carly Dillen, Alvaro Ordonez, Yong Chang, Sanjay Jain, Lynne Jones and Robert Sterling of The Johns Hopkins University.

Funding for this work was provided by a Nexus Award from the Johns Hopkins Institute for Clinical and Translational Research, which has been funded by the National Center for Advancing Translational Sciences and the National Institutes of Health Roadmap for Medical Research.

by Shawna Williams, shawna@jhmi.edu and Lauren Nelson, laurennelson@jhmi.edu

For press inquiries related to INBT, contact Mary Spiro, mspiro@jhu.edu