bioRxiv Science⌕ Search

Biology subjects

Karfusehr, C.

Publications and source records attributed to Karfusehr, C..

3 recordsLinked to original sources

Vesicle-templated self-assembly of freestanding multi-μm DNA shells

In the quest to create increasingly complex synthetic cell-mimicking systems, a wide range of DNA nanostructures have been developed to coat, permeabilize, sculpt, or otherwise functionalize lipid vesicles. In a complementary strategy, DNA architectures have been used as scaffolds to direct the growth of lipid membrane vesicles. Here we introduce a simple and broadly applicable method to realize freestanding, membrane-mimicking DNA shells: DNA shells are first assembled on the outer surface of giant unilamellar vesicles and then liberated by surfactant-mediated liposome removal. The resulting structures faithfully retain the geometry of their membrane template. We demonstrate the approach with two distinct classes of DNA tectons: a complex barrel-shaped DNA origami with programmable inter-subunit interactions, and a simple nanostar-inspired motif composed of only eleven oligonucleotides. The site-specific addressability of the former enable the rational design of binding interfaces, as demonstrated by controlled multilayer formation. The success of both strategies underscores the generality of our approach and the feasibility of creating shell-like compartments from different DNA architectures. This method enables the construction of tunable, DNA-only containers spanning the size range of eukaryotic cells, offering a fundamentally new type of compartmentalization for bottom-up synthetic biology.

synthetic biology↗

Self-assembled cell-scale containers made from DNA origami membranes

DNA origami provides a methodology for the sequence-programmable generation of precisely defined molecular nanostructures with sizes of order 100 nm. A new frontier for the field is the generation of superstructures made from DNA origami subunits, which requires other self-assembly strategies than those used for DNA origami itself. Challenges faced by current approaches include the increasing complexity, cost and development time for the structures and off-target assembly. Here, we demonstrate how radially symmetric origami subunits that are inspired by the structure and interactions of lipids organize into giant DNA origami monolayer membranes that can be readily programmed to form vesicles or hollow tubes with diameters ranging from 100 nm to over 1 {micro}m. DNA origami membranes are an unprecedented approach for compartmentalization that opens up new possibilities for bottom-up biology and cell-scale soft robotics.

synthetic biology↗

Collagen breaks at weak sacrificial bonds taming its mechanoradicals

Collagen is a force-bearing, hierarchical structural protein important to all connective tissue. In tendon collagen, high load even below macroscopic failure level creates mechanoradicals by homolytic bond scission, similar to polymers. The location and type of initial rupture sites critically decide on both the mechanical and chemical impact of these micro-ruptures on the tissue, but are yet to be explored. We here use scale-bridging simulations supported by gel electrophoresis and mass spectrometry to determine breakage points in collagen. We find collagen crosslinks, as opposed to the backbone, to harbor the weakest bonds, with one particular bond in trivalent crosslinks as the most dominant rupture site. We identify this bond as sacrificial, rupturing prior to other bonds while maintaining the materials integrity. Also, collagens weak bonds funnel ruptures such that the potentially harmful mechanoradicals are readily stabilized. Our results suggest this unique failure mode of collagen to be tailored towards combatting an early onset of macroscopic failure and material ageing.

biophysics↗