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*** We are hiring! ***

1) PhD projects: Several projects are available for students from various backgrounds including physics, chemistry (polymer chemistry, physical chemistry, or biochemistry), and biology (molecular), bioengineering, pharmacology or related subjects.
If you are not admitted to a graduate program at 91�ֿ�, yet: Please be aware that at US universities, students need to be accepted to a graduate program, do some courses and pass a “candidacy exams” prior to starting full-time research for their PhD project. Typically, you will also be a teaching assistant in a course or lab during the semester. If your previous degree is not in Physics, you may also check the graduate programs of the "Biomedical Sciences" program, particularly the Cell & Molecular Biology program, or the Material Science Graduate Program.

2) Undergraduate or graduate students for individual investigation, rotation, honor's theses or sophomore research projects. Students do not necessarily have to be Physics majors, and a background in Chemistry, Biochemistry, Computer Science and Molecular Biology is also highly welcome. Students just need to have a broader interest in single-molecule biophysics, molecular biology or biochemistry. Several projects are available depending on the student's backgrounds. Inquire for more information.

Lab News:

3/2023: TLS receives early teanure and will be promoted to associate professor effective next fall.

2/2023: Sarvinaz is admitted to the BMS graduate program. Congrats!

2/2023: Welcome our latest lab member, Angelina Felicitas Martinez, our new highspeed AFM. She quickly made new friends.

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​ 8/2021: We received a major 5-year award from the National Institutes of Health (NIGMS R35) for this project.​

8/2022: We received an instrumentation grant for a highspeed Atomic force microscope

3/2021: Our lab recently received an NSF EAGER award for developing our DNA-lipid nanodiscs into tools for single-molecule cryo-EM tools for membrane proteins.

Research Focus

​Why DNA?

​DNA is a unique polymer. It is the information storage molecule of all known life forms, but can also be used to build up complex, artificial structures that are not found in Biology. Our group is leveraging this programmability to engineer nanoscale architectures and tools for applications in Biophysics and Structural Biology. Moreover, we study fundamental mechanical properties of DNA that govern biological processes including transcription, gene regulation and packing in the nucleus.

​DNA-Lipid Nanodiscs as Tools for Single-Molecule Cryo-EM of Membrane Proteins

​A main focus of our group is to develop molecular tools that allow to study membrane proteins (MPs), which are among the most important, but least understood components of cells. All cells are surrounded by lipid membranes that are almost impermeable for water, salts or nutrients that cells need. For this reason, a large number of membrane protein(MPs) are inserted into the membranes that control cellular functions such as material transport, sensing, intercellular communication, cell adhesion, and energy conversion. MPs are also the targets for many therapeutic drug molecules. Knowledge of the molecular structure of MPs is necessary to understand the underlying molecular mechanisms of their function and can guide the development of therapeutic drugs for many common diseases. However, MPs are difficult to study and therefore the molecular structure of most MPs is still unknown. The goal of this project is to develop broadly applicable new tools using DNA nanotechnology that will facilitate solving MP structures with cryo-electron microscopes. .

Biophysics of Tightly Bent DNA

The nucleus of a human cell is only few micrometers long, but has to accommodate 2 meters of DNA. For this reason, cellular DNA is compacted in complex ways with DNA-binding proteins such as histones or by supercoiling to accommodate the limited available space. DNA compacting and the resulting high local curvature also plays a role in the regulation of gene expression and to protect DNA from mechanical damage.
Although DNA is arguably the best studied molecule in biophysics, the mechanics and dynamics of tightly bent DNA molecules such as DNA minicircles are not fully understood yet. Our lab combines experimental approaches including atomic force microscopy (AFM), single-molecule FRET (incollaboration with Hamza Balci's lab) and coarse grained molecular dynamics simulations (in collaboration with John Portman's lab) to discover exciting new behaviors of tightly bent DNA and intrinsically curved DNA sequences.

Other Research Interests

The projects below were primarily done in my previous lab in Dresden and are currently on ice until the group grows further.

DNA-Based Plasmonic Devices

The field of plasmonics exploits the interaction of light with nanoscale metallic structures to confine, guide and manipulate light on scales below the diffraction limit. Plasmonic structures exhibit significant potential for applications including quantum optics, sensing, and short-distance optical communication (a). Towards this goal, we demonstrated the precise, robust, and high-yield assembly of gold nanoparticles on DNA origami templates (b). 

More recently, we realized energy propagation through such a self-assembled waveguide to a fluorescent nanodiamond and out coupling of energy. We analyzed the waveguiding at a single-device level by electron energy loss spectroscopy (c) and cathodoluminescence imaging spectroscopy. Our work visually demonstrates the realization of nanometer-precise light manipulation and energy conversion. .

Finally, these closely spaced gold nanoparticles create a strong plasmonic hotspot for the sensing of molecules.

Triangulated DNA Origami and Nanomechanical Actuators

In the macroscopic world, stiff and material-efficient structures such as construction cranes and high voltage transmission towers are usually built from triangulated wireframe structures. We extended the DNA origami concept to generate a series of triangulated trusses. These provide defined cavities that we seek to fill with functional elements.

By introducing single-stranded regions edges of the wireframe trusses, the structures are heavily deformed due to the entropic spring forces contracting the single-stranded region. The gaps can be filled by a gap filling polymerase (such as the T4 polymerase) or the addition of the missing oligonucleotides, thus creating a nanomechanical actuator.

Outlook: This principle shall be the basis for stimuli-responsive mechanical nano devices in photonics or for applications in molecular biology. Moreover, we wish to determine biophysical properties such as their bending and torsional stiffness with super-resolution microscopy or optical tweezers.

Stabilizing DNA Structures for Nanomedicine

A main drawback of structural DNA nanotechnology is the instability of structures in biological environments. We developed a protection strategy based on block copolymer micellization which stabilizes DNA structures in biological or low-salt environments.

Outlook: We will use this protection to enhance DNA-based nanomedicines.

“Next-Generation” DNA Synthesis Methods

Synthetic oligonucleotides (short single-stranded DNA) and genes (long double-stranded DNA) are the main cost factor for many studies in DNA nanotechnology, genetics and synthetic biology. Inexpensive chip-synthesized oligonucleotide libraries can contain hundreds of thousands of distinct sequences, however only at sub-femtomole quantities per strand. We developed a selective oligonucleotide amplification method based on rolling circle amplification (RCA) with a 10-1000-fold cost-reduction compared to synthetic oligonucleotides or competing amplification methods such as PCR.

Outlook: We have recently extended our method for de novo gene synthesis. This will allow us to design custom scaffolds, and testing design principles that influence the folding kinetics and yields.

Group

Current group members (chronological):

• Praneetha Sundar Prakash: PhD candidate, Biomedical Sciences PhD Program
• Soumya Chandrasekhar: PhD candidate, Chemical Physics Interdisciplinary Program
• Sarvinaz Hajiyeva: PhD candidate, Biomedical Sciences PhD Program
• Daniel Hollis: Undergraduate research assistant
• Thomas Swope: Research assistatant, MS Physics
• Rachel Bricker: Undergraduate research assistant, Physics
• Pranav Srinivasan: Undergraduate research assistant, Physics
• Dr. Fatemeh Fadaei: Postdoc

Alumni, Their Next Career Steps and Current Positions if Known:

Former Postdocs

• 2021-2023    Dr. Sanjai Karanth: Postdoc at Fraunhofer Institute Freising, Germany
• 2019               Prof. Yusuke Sato: Associate Professor at Kyushu Institute of Technology, Japan
• 2019               Dr. Parastoo Maleki: Postdoc at University of Texas, Austin
• 2018-2019    Prof. Dr. Diana Goncalves-Schmidt: Assistant Professor at 91�ֿ�

Former PhD Students (Defended)

• 2014-2018    Prof. Dr. Fatih Nadi Gür: Postdoc at LMU Munich, now assistant professor at Shanghai Jiao Tong University
• 2014-2019    Dr. Michael Matthies: Postdoc at Arizona State University, now Postdoc at TU Munich
• 2014-2019    Dr. Nayan P. Agarwal: Postdoc at Massachusetts Institute of Technology (MIT),
• 2015-2019    Dr. Bastian Joffroy: Scientist at DKMS Dresden
• 2015-2019    Dr. Katarina Iric: Postdoc at TU Dresden, now scientist at Nanogami

Former Master’s Students

• 2021-2023    Draven Houser: Applications engineer at Presco Inc.
• 2019-2020    Alamgir Kabir: now PhD student, Toledo/Ohio
• 2017-2018    Olga Aftenieva: PhD candidate at TU Dresden
• 2016-2017    Dr. Shikhar Gupta: PhD at Leipzig University, now GenZ Capital
• 2016-2017    Dr. Foram M. Joshi:  PhD at TU Dresden, now bioengineer at Parallel Bio (Boston)
• 2015-2016    Dr. Jingjing Ye: PhD at University of Leipzig, now Product Manager at ZEISS Microscopy (Shanghai)
• 2015-2016    Eric Wiener: PhD candidate at U. Leipzig
• 2014-2015    Dr. Hafesudeen Sahabudeen: PhD at TU Dresden
• 2014-2015    Dr. Yavuz Uca. PhD candidate at Charite Berlin
• 2014-2015    Dr. Michael Matthies: stayed in group for PhD thesis
• 2014-2015    Dr. Nayan Agarwal: stayed in group for PhD thesis

Former Research Assistants and Lab Managers

• 2022-2023    Philip Dudones:  PhD candidate at Case Western Research University (Physics)
• 2022-2023    Holly Matthews: PhD candidate at Michigan State University (Physics)
• 2019-2021     Brady Weber: Lab manager in Biology department.
• 2018               Chloe Jones, PhD candidate
• 2017                Dr. Ashwin Natarajan Karthick, PhD at Aalto University, now postdoc at Max Delbrück Center, Berlin.
• 2017-2018    Kristin Joffroy: Staff Scientist at DKMS Dresden
• 2014-2016    Simon Ahrens: Technician and Lab Manager, Paternity leave

Further Reading

For more information, I recommend this 3-hour lecture (iBiology) by William Shih:

or a current review on structural DNA nanotechnology such as: