Research Interests
Cellular membranes are vital components of biological cells. They form a protective layer that is impermeable to most molecules, and that plays an important role in mediating transport processes and protein organization.
How does spatial order emerge in cellular membranes? It has become clear that phospholipids and sterols play a major role in the lateral organization in such membranes. Using computer simulations and analytical models we explore the patterns that can emerge spontaneously in multicomponent membranes.
In addition to lateral composition heterogeneities, cell membranes can contribute to the organization of membrane proteins through the behavior of their shape deformations. When proteins bind to membranes they locally change elastic properties and limit the range of accessible fluctuations. We investigate how these effects can result in the structured assembly of membrane proteins.
Metal nanoaprticles cross-linked with double-stranded DNA can form a wide range of aggregates that exhibit many surprising and useful properties. Precise control over the aggregate structure is required to tune the mechanical and optical properties of these new materials. Such control can be achieved by carefully designing the nucleic acid sequence of the DNA cross linkers. Technology that allows to synthesize DNA with nearly arbitrary sequence is now readily available.
Even more advanced materials can be constructed when one uses control parameters in addition to DNA sequence. We are currently exploring the utility of photoswitch-modified DNA in the directed and reversible aggregation of metal nanoparticle aggregates. Incorporating azobenzene moieties into DNA provides control over the assembly process that can be easily exercised by light. This element of control is sensitive to the nucleic acid sequence, which opens the door for several DNA sensing applications.
Would you like to learm more about our work?
People
Lutz Maibaum
Shushan He
Nihit Pokhrel
Raymond Jin
Yongtian Luo
James Ludwig
Jesse Prelesnik
Felix Leeb
News
Resolving Cholesterol-Phospholipid Interactions
Cholesterol has strong effects on the properties of phospholipid bilayers. For example, it induces ordering of the phospholipids’ alkyl tails. Felix’s new paper, featured on the BPS Blog, describes the spatial range of such effects.
Phase behavior of spherical vesicles
Vesicles are small, spherical objects made of phospholipid bilayers. Yongtian’s paper, published in the Journal of Chemical Physics, describes how this geometry changes the thermodynamic behavior of the phospholipids.
When do lipids (de-)mix?
Whether or not a mixture of multiple lipids forms a homogeneous bilayer is an important, and surprisingly difficult, problem in membrane biophysics. Shushan’s recent paper describes a new method that allows the accurate calculation of mixing phase-diagrams from coarse-grained simulations.
How do small molecules cross biological membranes?
Small molecules often cross biological membranes by translocation. Multiple computational methods can be used to study this process. Nihit’s work addresses which of these methods works best (and why!), as you can read in this preprint.
Kayla’s work on membrane-mediated protein interactions
When proteins bind to cell membranes they affect local membrane properties. In particular, the membrane can no longer fluctuate the way a free membrane would: the proteins suppress membrane fluctuations, which is entropically unfavorable. This results in a membrane-mediated interaction among membrane-bound proteins. You can read more about this effect in Kayla’s recent paper, which Read more about Kayla’s work on membrane-mediated protein interactions[…]
Addie’s paper on photoswitch-modified DNA is published
Addie’s work on understanding the sequence dependence of azobenzene quantum yield in DNA, a collaboration with the Ginger group, has been published in the Journal of Physical Chemistry Letters. You can access the paper though this link.
Addie and Nihit win prestigious departmental awards
Addie and Nihit were recognized with prestigious awards for their outstanding contributions to the department: Addie received the Lyle H. Jensen Graduate Fellowship, and Nihit earned the Usha and S. Rao Varanasi Endowed Diversity Scholarship in Chemistry. Congratulations!