Biomembranes provide a dynamic substrate for the biomolecular interactions that underlie spatial organization, signaling, and global response in cells. One important function of lipid membranes is compartmentalization, a fundamental feature of all cells and a powerful enabler of cellular complexity.
Increasing knowledge about the composition and dynamics of cell membranes in combination with advances in recombinant protein expression and methods for forming synthetic membranes have enabled a new approach to the study of biomembranes: the construction of cell-like bioassemblies.
Reconstructing important aspects of cellular function from the bottom up using component biological parts is an emerging area of research that has the capacity to fundamentally test our understanding of biomembranes and enable the design of biosynthetic hybrid devices that could revolutionize biodetection, therapeutics, and bioenergy.
Our research group is approaching the construction of simplified cell-like bioassemblies by using unique strategies for synthesis, assembly, and characterization.
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Through our synthesis lab, we can create a wide range of lipid architectures with coupled functions that are tuned to specific experimental conditions. Molecular-recognition sites, metal chelators, optical reporters, polymerizable groups, fluorocarbons, isotopic labels, semiconductors, and photoswitches have been incorporated into amphiphiles to generate lipid assemblies with novel structures and functions and to enable the dynamic characterization of membrane organization.
We assemble model membranes, including supported lipid bilayers and small-to-giant unilamellar vesicles. We study membrane architectures, such as microdomains, rafts, buds, and tubules, by using cell-like lipid mixtures and synthetic functionalized lipids. We also use microfluidic vesicle encapsulation to encapsulate complex biochemical mixtures and aggregates inside unilamellar lipid vesicles so that we can create cell-like model systems.
We use a variety of optical characterization techniques, including wide-field and scanning confocal microscopy. A unique capability of our lab is time-resolved multispectral confocal microscopy, which simultaneously measures fluorescence spectra and lifetimes. Confocal microscopy can also record the photon-by-photon history of the fluorescence characteristics of single molecules. This imaging approach enables us to probe chemical environments (e.g., polarity and viscosity) within our samples and also perform multiparameter fluctuation correlation measurements for diffusion studies.