Biology subjects

Rothfischer, F.

Publications and source records attributed to Rothfischer, F..

3 recordsLinked to original sources

bioRxiv2026

Magnetic DNA Origami Nanorotors

Self-assembled DNA nanostructures show great promise as functional devices, highly configurable materials, and in nanorobotics. Magnetic control can provide a powerful actuation mechanism in a broad range of contexts, since it affords a high-level of external control, it is biocompatible, and orthogonal to chemical or electrical stimuli. Here we demonstrate magnetic molecular nanoactuators by leveraging the unique site-specificity of DNA origami to assemble highly anisotropic magnetic nanocubes on high-aspect ratio DNA origami bundles. We traced and controlled 100s of our DNA origami nanorotors at the single-rotor level and demonstrated their programmable magnetic clamping and controlled rotation under uniform and rotating magnetic fields. By varying the population and inter-particle spacing of the nanocubes, magnetic torque values in the order of 10-100 pN nm are achieved at field strengths < 10 mT. Monte Carlo simulations reveal that assembly of nanocubes on DNA origami rotors leads to collective magnetic properties, with numerically estimated torque values in good agreement with the experiments. Our magnetic nanorotors offer a foundation for biocompatible nanorobotics, as well as high-throughput magnetic force and torque tweezers.

biophysics↗

bioRxiv2024

From Brownian to deterministic motor movement in a DNA-based molecular rotor

Molecular devices that have an anisotropic, periodic potential landscape can be operated as Brownian motors. When the potential landscape is cyclically switched with a chemical reaction or an external force, such devices can harness random Brownian fluctuations to generate directed motion. Recently, directed Brownian motor-like rotatory movement was demonstrated with an electrically switched DNA origami rotor with designed, ratchet-like obstacles. Here, we demonstrate that also the intrinsic anisotropy of DNA origami rotors that originally were not designed as Brownian motor devices is sufficient to result in motor movement. We show that for low amplitudes of an external switching field such devices operate as Brownian motors, while at higher amplitudes the movement is better described by the deterministic motion of an overdamped electrical motor. We characterize the amplitude and frequency dependence of the movements in both regimes, showing that after an initial steep rise the angular speed peaks and drops for excessive driving amplitudes and frequencies. The characteristics of the rotor movement are well described by a simple stochastic model of the system.

biophysics↗

bioRxiv2021

Synthetic cell-based materials extract positional information from morphogen gradients

Dynamic biomaterials composed of synthetic cellular structures have the potential to adapt and functionally differentiate guided by physical and chemical cues from their environment. Inspired by developing biological systems, which efficiently extract positional information from chemical morphogen gradients in the presence of environmental uncertainties, we here investigate the analogous question: how well can a synthetic cell determine its position within a synthetic multicellular structure? In order to calculate positional information in such systems, we created and analyzed a large number of replicas of synthetic cellular assemblies, which were composed of emulsion droplets connected via lipid bilayer membranes. The droplets contained cell-free two-node feedback gene circuits that responded to gradients of a genetic inducer acting as a morphogen. We found that in our system, simple anterior-posterior differentiation is possible, but positional information is limited by gene expression noise, and is also critically affected by the temporal evolution of the morphogen gradient and the life-time of the cell-free expression system contained in the synthetic cells. Using a 3D printing approach, we demonstrate morphogen-based differentiation also in larger tissue-like assemblies.

synthetic biology↗