Group Leader<\/h1><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<\/div>![\"\"](\"http:\/\/research.phys.cmu.edu\/deserno\/wp-content\/uploads\/sites\/6\/2021\/08\/Deserno-1-400x500-1.png\" "\\"Deserno-1-400x500\\"")
<\/span>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\tMarkus Deserno<\/h3>\n
Professor of Physics<\/p>\n
PhD 2000<\/span><\/a> (Max-Planck-Institute for Polymer Research<\/a><\/span> & University of Mainz<\/a><\/span><\/span>, Germany)<\/span><\/p>\nDepartment of Physics
Carnegie Mellon University
5000 Forbes Avenue
Pittsburgh, PA 15213, USA<\/p>\n
office:<\/span> Wean Hall 6319; email:<\/span> deserno@andrew.cmu.edu<\/a><\/p>\nI am interested in theoretical and computational biophysics, with a particular focus on lipid membranes. Computationally I use coarse-grained models of membranes, especially those of low resolution, and theoretically I apply a wide spectrum of techniques, ranging from continuum mechanics and differential geometry to statistical field theory.<\/p><\/div>\n\t\t\t<\/div>
\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\tFollow<\/span><\/a><\/li>Follow<\/span><\/a><\/li>Follow<\/span><\/a><\/li>\n\t\t\t<\/ul>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\tCurrent members<\/h1><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<\/a><\/p>\nSeamus Gallagher<\/h4><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<\/div>![\"\"](\"http:\/\/research.phys.cmu.edu\/deserno\/wp-content\/uploads\/sites\/6\/2024\/02\/Seamus-Gallagher.jpeg\" "\\"Seamus-Gallagher\\"")
<\/span>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\tIn his thesis project, Seamus investigates membrane fusion\u2014specifically how it is affected by the presence of lipids that increase the value of the Gaussian curvature modulus. Developing coarse-grained lipid models whose mean and Gaussian moduli are well controlled, the impact of \"negative Gaussian curvature lipids\" on fusion can be systematically studied. This has far-reaching implicatiions for drug delivery based on lipid nanoparticles.<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div>
\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<\/a><\/p>\nMalavika Varma<\/h4><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<\/div>![\"\"](\"http:\/\/research.phys.cmu.edu\/deserno\/wp-content\/uploads\/sites\/6\/2021\/08\/Malavika-Varma.jpeg\" "\\"Malavika-Varma\\"")
<\/span>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\tIn her graduate work, Malavika investigates the role cholesterol plays in the biophysics of asymmetric lipid membranes. She uses coarse-grained simulations and simple elastic models to understand how partitioning differences between the leaflets in conjunction with differential stress determines cholesterol's distribution.<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div>
\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<\/a><\/p>\nFarid Khuri-Makdisi<\/h4><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<\/div>![\"\"](\"http:\/\/research.phys.cmu.edu\/deserno\/wp-content\/uploads\/sites\/6\/2024\/02\/Farid-Khuri-Makdisi.png\" "\\"Farid-Khuri-Makdisi\\"")
<\/span>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\tFarid is an undergraduate student who has been working on two projects: he assisted Malavika Varma in a project that develops ternary mixtures in the coarse-grained lipid Cooke model that are capable of exhibiting Lo<\/sub>-Ld<\/sub> phase coexistence. Farid is also developing coarse grained models for conical \"nano-hats\" that can bind with their inside to membranes\u2014a project connected to a collaboration with the lab of Rebecca Taylor<\/a>.<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\tAlumni<\/h1><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<\/a><\/p>\nSamuel L. Foley<\/h4>\n
(2023)<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>
\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\tSam graduated with a Ph.D. thesis entitled \"Mechanics and Thermodynamics of Differentially Stressed Lipid Membranes: Theory and Coarse-Grained Simulation<\/strong>.\" In his first important paper he devised a procedure by which lipids in the coarse grained Cooke model can be kept on the side they started out with, thus enabling the simulation of asymmetric membranes (even with sizable differential stress) in this highly coarse-grained system [J. Chem. Theory Comput. 16<\/strong>, 7195\u20137206 (2020)<\/span><\/a>]. Using this model, he showed that the fluid-gel transition of membranes changes in the presence of differential stress becomes very interesting (permitting phase coexistence in each leaflet even at a fixed temperature and net (zero) tension), and he developed a very neat theory for this that takes its inspiration from two coupled van der Waals gases [Biophys. J. 121<\/strong>, 2997\u20133009 (2022)<\/a>]. He is also lead author on a nice mini-review that summarizes many of our recent asymmetry findings [Emerg. Top. Life Sci. 7<\/strong>, 95\u2013110 (2023)<\/a>]. And in his final thesis project Sam developed a method by which we can simulate membranes whose area and curvature are free to relax in simualtion\u2014a feat he accomplished by cutting the usual periodic boundary conditions open along one direction and bandaging the resulting open edges with a patch we call \"sticky tape\".<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<\/a><\/p>\nMuhammed F. Erg\u00fcder<\/h4>\n
(2022)<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>
\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\tMuhammed received his PhD with a thesis on \"Algorithmic Improvements for Extracting Lipid Bilayer Elastic Moduli from Height and Director Fluctuations<\/strong>.\" He examined the way that elastic membrane moduli are typically extracted in Molecular Dynamics simulations and investigated the (many) statistical and systematic unceryainties that arise in this process. He first provided computational support to the theoretocal work of Mert Terzi, which proposed a consistent quadratic theory of bilayer curvature elasticity that includes both shape and tilt [J. Chem. Phys. 151, 164108 (2019)<\/a>] and later spearheaded the investigation that examined in detail the systematic dependencies of elastic moduli on details of the continuum mapping [J. Chem. Phys. 154<\/strong>, 214103 (2021)<\/a><\/span>].<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<\/a><\/p>\nAmirali Hossein<\/h4>\n
(2021)<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>
\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\tAmirali graduated with a Ph.D. thesis entitled \"Investigation of Mechanical Properties of Asymmetric Lipid Bilayers via Coarse-Grained Simulation<\/strong>.\" He used coarse grained simulations (Martini model) combined with elasticity theory to examine the consequences of lipid membrane asymmetry. His first paper [Biophys. J. 118<\/strong>, 624\u2013642 (2020)<\/a>] made a big impact in the community: he showed that the interplay between lipid intrinsic curvature and packing can give rise to a difference in mechanical tension between the two membrane leaflets\u2014a condition he termed \"differential stress<\/em>\". He in particular showed that beyond some critical value this stress all by itself can drive a stiffening transition in membranes. He followed this up in a second paper that investigated the relation between this transition and the membrane's main phase transition [J. Chem. Phys. 154<\/strong>, 014704 (2021)<\/a>], a topic later pursued in more detail by Sam Foley, with Amirali also contributing [Biophys. J. 121<\/strong>, 2977\u20133009 (2022)<\/a>]. Amirali is also a co-author on a nice mini-review that summarizes many of these findings [Emerg. Top. Life Sci. 7<\/strong>, 95\u2013110 (2023)<\/a>].<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<\/a><\/p>\nDaniel Glazer<\/h4>\n
(2019)<\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>
\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\tDaniel was an undergrad student who investigated fluctuations of membtane buckles far away from the weakly-deformed regime. Specifically, he investigated the second variation of the planar Euler-buckling functional, which leads to Lam\u00e9 functions.<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div>
\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<\/a><\/p>\nDerek Hamersly<\/h4>\n
(2019)<\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>
\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\tDerek was an undergrad who ran simulations of Cooke-model asymmetric membranes. He was especially interested in what happens when they gets close to their gel transition.<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div>
\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<\/a><\/p>\nFred Dauphin<\/h4>\n
(2019)<\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>
\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\tFred was an undergrad who worked with us on the phase behavior of asymmetric lipid membranes.<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div>
\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<\/a><\/p>\nVikranth Mallikarjun<\/h4>\n
(2019)<\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>
\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\tVikranth was a high school summer student who worked with us on coarse-grained simulations of asymmetric lipid membranes.<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div>
\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<\/a><\/p>\nYiheng Zhang (\u5f20\u4e00\u6052)<\/h4>\n
(2017\u20132018)<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>
\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\tYiheng visited us as an exchange student between the fall of 2017 and the fall of 2018. Back then, he was working towards his PhD in the group of Zhanchun Tu<\/a> at Beijing Normal University, interested in the dynamics of active matter. While working here, Yiheng developed a theoretical framework to study the motion of topological defects in active liquid crystals confined to the surface of a sphere. In fact, he could basically boil down the problem to a set of ordinary differential equations satisfied by the defects and their orientation, which he then published [Phys. Rev. E\u00a0102<\/strong>, 012607 (2020)<\/a><\/span>]. Fun fact: he has also worked on first integrals of the axisymmetric membrane shape equation [Chinese Physics B 27<\/strong>, 038704 (2018)<\/a><\/span>], which he published with Zach<\/a> and Zhanchun.<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<\/a><\/p>\nM. Mert Terzi<\/h4>\n
(2014\u20132018)<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>
\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\tMert graduated with a thesis on \"Curvature-Tilt Theories of Lipid Membranes<\/strong>.\" He used covariant differential geometric techniques, combined with thin plane continuum elasticity, to systematically construct energy functionals for fluid lipid membranes. Following a famous paper by Hamm and Kozlov<\/a><\/span>, he reproduces their results, but argued for the existence of an additional tilt-curvature coupling term [J. Chem. Phys. 147<\/strong>, 084702 (2017)<\/a><\/span>]. Mert later found out that there are even more quadratic terms missing, as outlined in a (hopefully!) consistent functional he proposed two years later [J. Chem. Phys. 151<\/strong>, 164108 (2019)<\/a><\/span>] (tested numerically by Muhammed Erg\u00fcder<\/a>), and he had a first stab at bi-quadratric terms (quadratic in tilt and curvature) [CISM lecture notes 577<\/strong><\/a><\/span>]. In an additional project, Mert investigated the Poisson ratio of membranes, showing it to be very close to \u03bd = \u00bd, but with a possibly intriguing dependence on membrane depth [Soft Matter 15<\/strong>, 9085\u20139092 (2019)<\/a><\/span>].<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t<\/a><\/p>\nPablo V\u00e1zquez-Montejo<\/h4>\n
(2014\u20132015)<\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>
\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\tPablo joined as a postdoc, having just graduated with Jemal Guven<\/a>. He is an expert in filament\/membrane elasticity and differential geometry, and he was instrumental in two exciting projects, both done in collaboration with Zach<\/a>. In the first, Pablo investigated the shapes taken by close elastic filaments constricted to reside on the surface of an infinite cylinder, in particular their stability and the forces constraining them to the surface [Phys. Rev. E 91<\/strong>, 063203 (2015)<\/a><\/span>]. In the second project, Pablo investigated the binding energetics of open filaments (with a net spontaneous curvature) binding to the neck region of a catenoid [Biophys. J. 111<\/strong>, 2470\u20132480 (2016)<\/a><\/span>]. If in particular the filaments can change their length (being coupled to a reservoir of \"monomers\" of chemical potential \u03bc), their length and constriction force becomes complicated functions of the ratio between neck- and filament curvature, with multiple interesting implications to the (im-)possibility of dynamin-mediated membrane fission being driven entirely by passive processes.<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t
<\/span>\n\t\t\t<\/div>\n\t\t\t<\/div>Markus Deserno<\/h3>\n
Professor of Physics<\/p>\n
PhD 2000<\/span><\/a> (Max-Planck-Institute for Polymer Research<\/a><\/span> & University of Mainz<\/a><\/span><\/span>, Germany)<\/span><\/p>\n Department of Physics office:<\/span> Wean Hall 6319; email:<\/span> deserno@andrew.cmu.edu<\/a><\/p>\n I am interested in theoretical and computational biophysics, with a particular focus on lipid membranes. Computationally I use coarse-grained models of membranes, especially those of low resolution, and theoretically I apply a wide spectrum of techniques, ranging from continuum mechanics and differential geometry to statistical field theory.<\/p><\/div>\n\t\t\t<\/div> <\/a><\/p>\n In his thesis project, Seamus investigates membrane fusion\u2014specifically how it is affected by the presence of lipids that increase the value of the Gaussian curvature modulus. Developing coarse-grained lipid models whose mean and Gaussian moduli are well controlled, the impact of \"negative Gaussian curvature lipids\" on fusion can be systematically studied. This has far-reaching implicatiions for drug delivery based on lipid nanoparticles.<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div> In her graduate work, Malavika investigates the role cholesterol plays in the biophysics of asymmetric lipid membranes. She uses coarse-grained simulations and simple elastic models to understand how partitioning differences between the leaflets in conjunction with differential stress determines cholesterol's distribution.<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div> <\/a><\/p>\n Farid is an undergraduate student who has been working on two projects: he assisted Malavika Varma in a project that develops ternary mixtures in the coarse-grained lipid Cooke model that are capable of exhibiting Lo<\/sub>-Ld<\/sub> phase coexistence. Farid is also developing coarse grained models for conical \"nano-hats\" that can bind with their inside to membranes\u2014a project connected to a collaboration with the lab of Rebecca Taylor<\/a>.<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div> <\/a><\/p>\n (2023)<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div> Sam graduated with a Ph.D. thesis entitled \"Mechanics and Thermodynamics of Differentially Stressed Lipid Membranes: Theory and Coarse-Grained Simulation<\/strong>.\" In his first important paper he devised a procedure by which lipids in the coarse grained Cooke model can be kept on the side they started out with, thus enabling the simulation of asymmetric membranes (even with sizable differential stress) in this highly coarse-grained system [J. Chem. Theory Comput. 16<\/strong>, 7195\u20137206 (2020)<\/span><\/a>]. Using this model, he showed that the fluid-gel transition of membranes changes in the presence of differential stress becomes very interesting (permitting phase coexistence in each leaflet even at a fixed temperature and net (zero) tension), and he developed a very neat theory for this that takes its inspiration from two coupled van der Waals gases [Biophys. J. 121<\/strong>, 2997\u20133009 (2022)<\/a>]. He is also lead author on a nice mini-review that summarizes many of our recent asymmetry findings [Emerg. Top. Life Sci. 7<\/strong>, 95\u2013110 (2023)<\/a>]. And in his final thesis project Sam developed a method by which we can simulate membranes whose area and curvature are free to relax in simualtion\u2014a feat he accomplished by cutting the usual periodic boundary conditions open along one direction and bandaging the resulting open edges with a patch we call \"sticky tape\".<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div> <\/a><\/p>\n (2022)<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div> Muhammed received his PhD with a thesis on \"Algorithmic Improvements for Extracting Lipid Bilayer Elastic Moduli from Height and Director Fluctuations<\/strong>.\" He examined the way that elastic membrane moduli are typically extracted in Molecular Dynamics simulations and investigated the (many) statistical and systematic unceryainties that arise in this process. He first provided computational support to the theoretocal work of Mert Terzi, which proposed a consistent quadratic theory of bilayer curvature elasticity that includes both shape and tilt [J. Chem. Phys. 151, 164108 (2019)<\/a>] and later spearheaded the investigation that examined in detail the systematic dependencies of elastic moduli on details of the continuum mapping [J. Chem. Phys. 154<\/strong>, 214103 (2021)<\/a><\/span>].<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div> <\/a><\/p>\n (2021)<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div> Amirali graduated with a Ph.D. thesis entitled \"Investigation of Mechanical Properties of Asymmetric Lipid Bilayers via Coarse-Grained Simulation<\/strong>.\" He used coarse grained simulations (Martini model) combined with elasticity theory to examine the consequences of lipid membrane asymmetry. His first paper [Biophys. J. 118<\/strong>, 624\u2013642 (2020)<\/a>] made a big impact in the community: he showed that the interplay between lipid intrinsic curvature and packing can give rise to a difference in mechanical tension between the two membrane leaflets\u2014a condition he termed \"differential stress<\/em>\". He in particular showed that beyond some critical value this stress all by itself can drive a stiffening transition in membranes. He followed this up in a second paper that investigated the relation between this transition and the membrane's main phase transition [J. Chem. Phys. 154<\/strong>, 014704 (2021)<\/a>], a topic later pursued in more detail by Sam Foley, with Amirali also contributing [Biophys. J. 121<\/strong>, 2977\u20133009 (2022)<\/a>]. Amirali is also a co-author on a nice mini-review that summarizes many of these findings [Emerg. Top. Life Sci. 7<\/strong>, 95\u2013110 (2023)<\/a>].<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div> (2019)<\/div>\n\t\t\t<\/div>\n\t\t\t<\/div> Daniel was an undergrad student who investigated fluctuations of membtane buckles far away from the weakly-deformed regime. Specifically, he investigated the second variation of the planar Euler-buckling functional, which leads to Lam\u00e9 functions.<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div> (2019)<\/div>\n\t\t\t<\/div>\n\t\t\t<\/div> Derek was an undergrad who ran simulations of Cooke-model asymmetric membranes. He was especially interested in what happens when they gets close to their gel transition.<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div> (2019)<\/div>\n\t\t\t<\/div>\n\t\t\t<\/div> Fred was an undergrad who worked with us on the phase behavior of asymmetric lipid membranes.<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div> (2019)<\/div>\n\t\t\t<\/div>\n\t\t\t<\/div> Vikranth was a high school summer student who worked with us on coarse-grained simulations of asymmetric lipid membranes.<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div> <\/a><\/p>\n (2017\u20132018)<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div> Yiheng visited us as an exchange student between the fall of 2017 and the fall of 2018. Back then, he was working towards his PhD in the group of Zhanchun Tu<\/a> at Beijing Normal University, interested in the dynamics of active matter. While working here, Yiheng developed a theoretical framework to study the motion of topological defects in active liquid crystals confined to the surface of a sphere. In fact, he could basically boil down the problem to a set of ordinary differential equations satisfied by the defects and their orientation, which he then published [Phys. Rev. E\u00a0102<\/strong>, 012607 (2020)<\/a><\/span>]. Fun fact: he has also worked on first integrals of the axisymmetric membrane shape equation [Chinese Physics B 27<\/strong>, 038704 (2018)<\/a><\/span>], which he published with Zach<\/a> and Zhanchun.<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div> <\/a><\/p>\n (2014\u20132018)<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div> Mert graduated with a thesis on \"Curvature-Tilt Theories of Lipid Membranes<\/strong>.\" He used covariant differential geometric techniques, combined with thin plane continuum elasticity, to systematically construct energy functionals for fluid lipid membranes. Following a famous paper by Hamm and Kozlov<\/a><\/span>, he reproduces their results, but argued for the existence of an additional tilt-curvature coupling term [J. Chem. Phys. 147<\/strong>, 084702 (2017)<\/a><\/span>]. Mert later found out that there are even more quadratic terms missing, as outlined in a (hopefully!) consistent functional he proposed two years later [J. Chem. Phys. 151<\/strong>, 164108 (2019)<\/a><\/span>] (tested numerically by Muhammed Erg\u00fcder<\/a>), and he had a first stab at bi-quadratric terms (quadratic in tilt and curvature) [CISM lecture notes 577<\/strong><\/a><\/span>]. In an additional project, Mert investigated the Poisson ratio of membranes, showing it to be very close to \u03bd = \u00bd, but with a possibly intriguing dependence on membrane depth [Soft Matter 15<\/strong>, 9085\u20139092 (2019)<\/a><\/span>].<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div> (2014\u20132015)<\/div>\n\t\t\t<\/div>\n\t\t\t<\/div> Pablo joined as a postdoc, having just graduated with Jemal Guven<\/a>. He is an expert in filament\/membrane elasticity and differential geometry, and he was instrumental in two exciting projects, both done in collaboration with Zach<\/a>. In the first, Pablo investigated the shapes taken by close elastic filaments constricted to reside on the surface of an infinite cylinder, in particular their stability and the forces constraining them to the surface [Phys. Rev. E 91<\/strong>, 063203 (2015)<\/a><\/span>]. In the second project, Pablo investigated the binding energetics of open filaments (with a net spontaneous curvature) binding to the neck region of a catenoid [Biophys. J. 111<\/strong>, 2470\u20132480 (2016)<\/a><\/span>]. If in particular the filaments can change their length (being coupled to a reservoir of \"monomers\" of chemical potential \u03bc), their length and constriction force becomes complicated functions of the ratio between neck- and filament curvature, with multiple interesting implications to the (im-)possibility of dynamin-mediated membrane fission being driven entirely by passive processes.<\/p><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div>
Carnegie Mellon University
5000 Forbes Avenue
Pittsburgh, PA 15213, USA<\/p>\n\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t
Current members<\/h1><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div>
Seamus Gallagher<\/h4><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>
<\/span>\n\t\t\t<\/div>\n\t\t\t<\/div>Malavika Varma<\/h4><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>
<\/span>\n\t\t\t<\/div>\n\t\t\t<\/div>Farid Khuri-Makdisi<\/h4><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>
<\/span>\n\t\t\t<\/div>\n\t\t\t<\/div>Alumni<\/h1><\/div>\n\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div>
Samuel L. Foley<\/h4>\n
Muhammed F. Erg\u00fcder<\/h4>\n
Amirali Hossein<\/h4>\n
Daniel Glazer<\/h4>\n
Derek Hamersly<\/h4>\n
Fred Dauphin<\/h4>\n
Vikranth Mallikarjun<\/h4>\n
Yiheng Zhang (\u5f20\u4e00\u6052)<\/h4>\n
M. Mert Terzi<\/h4>\n
Pablo V\u00e1zquez-Montejo<\/h4>\n