Publications related to Tuning knot abundance in semiflexible chains with crowders of different sizes: a Monte Carlo study of DNA chains

Capsizing due to friction-induced twist in the failure of stopper knots

Pedro Miguel Nunes Pereira de Almeida Reis, Paul Johanns

We investigate the failure mechanism of stopper knots, with a particular focus on the figure -8 knot as a representative example. Stopper knots are widely used in climbing, sailing, racket stringing, and sewing to maintain tension in ropes, strings, or thr ...

Elsevier2024

Mechanics of Physical Knots: From Filaments in Contact to Surgical Suturing

Paul Johanns

In this thesis, we study the mechanics of tight physical knots. Knots are omnipresent in surgery, climbing, and sailing, with disastrous consequences when the filament or the rope fails to perform its function. Even if the importance of mechanical analysis ...

EPFL2023

The strength of surgical knots involves a critical interplay between friction and elastoplasticity

Paul Grandgeorge, Pedro Miguel Nunes Pereira de Almeida Reis, Paul Johanns, Changyeob Baek

Knots are the weakest link in surgical sutures, serving as mechanical ligatures between filaments. Exceeding their safe operational limits can cause fatal complications. The empirical nature of present guidelines calls for a predictive understanding of the ...

AMER ASSOC ADVANCEMENT SCIENCE2023

Computational Exploration of Multistable Elastic Knots

Mark Pauly, Michele Vidulis, Yingying Ren

We present an algorithmic approach to discover, study, and design multistable elastic knots. Elastic knots are physical realizations of closed curves embedded in 3-space. When endowed with the material thickness and bending resistance of a physical wire, t ...

2023

Achieving high hybridization density at DNA biosensor surfaces using branched spacer and click chemistry

Mounir Driss Mensi, Sandrine Gerber, Lucas Mayoraz, Perrine Agnes Edith Robin, Alireza Kavand

The COVID-19 pandemic has highlighted the necessity to develop fast, highly sensitive and selective virus detection methods. Surface-based DNA-biosensors are interesting candidates for this purpose. Functionalization of solid substrates with DNA must be pr ...

2023

A field-capable rapid plant DNA extraction protocol using microneedle patches for botanical surveying and monitoring

Sebastian Maerkl, Jonathan Selz, Nicolas Rémi Adam

PremiseA novel protocol for rapid plant DNA extraction using microneedles is proposed, which supports botanic surveys, taxonomy, and systematics. This protocol can be conducted in the field with limited laboratory skills and equipment. The protocol is vali ...

WILEY2023

Development of multiplexed single-molecule imaging techniques to study chromatin invasion dynamics of chromatin effector proteins

Kristina Makasheva

DNA-binding proteins physically interact with the DNA and directly affect genomic functions. The eukaryotic genome is compacted into chromatin, limiting the DNA access to nuclear factors. In this Ph.D. thesis, I explored the dynamic mechanisms, that allow ...

EPFL2023

Exploring the inner workings of the clove hitch knot

Paul Grandgeorge, Pedro Miguel Nunes Pereira de Almeida Reis, Paul Johanns, Tomohiko Sano, Changyeob Baek

We perform a combined experimental and computational investigation of the clove hitch knot. We develop a physical model for the clove hitch by tying an elastic rod onto a rigid cylinder. In the experiments, we characterize the mechanical performance, geome ...

ELSEVIER2022

Polydimethylsiloxane microstructure-induced acoustic streaming for enhanced ultrasonic DNA fragmentation on a microfluidic chip

Thomas Lehnert, Martinus Gijs, Lin Sun

Next-generation sequencing (NGS) is an essential technology for DNA identification in genomic research. DNA fragmentation is a critical step for NGS and doing this on-chip is of great interest for future integrated genomic solutions. Here we demonstrate fa ...

ROYAL SOC CHEMISTRY2022

The shapes of physical trefoil knots

John Maddocks, Paul Grandgeorge, Pedro Miguel Nunes Pereira de Almeida Reis, Paul Johanns, Tomohiko Sano, Changyeob Baek

We perform a compare-and-contrast investigation between the equilibrium shapes of physical and ideal trefoil knots, both in closed and open configurations. Ideal knots are purely geometric abstractions for the tightest configuration tied in a perfectly fle ...

2021

m6A methylation potentiates cytosolic dsDNA recognition in a sequence-specific manner

Andrea Ablasser, Muhammet Fatih Gülen

Nucleic acid sensing through pattern recognition receptors is critical for immune recognition of microbial infections. Microbial DNA is frequently methylated at the N-6 position of adenines (m6A), a modification that is rare in mammalian host DNA. We show ...

ROYAL SOC2021

Sequence-dependent structural properties of B-DNA: what have we learned in 40 years?

John Maddocks, Daiva Petkeviciute, Paolo Carloni, Marco Pasi, Rahul Sharma

The structure of B-DNA, the physiological form of the DNA molecule, has been a central topic in biology, chemistry and physics. Far from uniform and rigid, the double helix was revealed as a flexible and structurally polymorphic molecule. Conformational ch ...

Springernature2021

Finite Element Modeling of Tight Elastic Knots

Paul Grandgeorge, Pedro Miguel Nunes Pereira de Almeida Reis, Paul Johanns, Tomohiko Sano, Changyeob Baek

We present a methodology to simulate the mechanics of knots in elastic rods using geometrically nonlinear, full three-dimensional (3D) finite element analysis. We focus on the mechanical behavior of knots in tight configurations, for which the full 3D defo ...

2020

Redox Properties of Native and Damaged DNA from Mixed Quantum Mechanical/Molecular Mechanics Molecular Dynamics Simulations

Ursula Röthlisberger, Ivano Tavernelli, Polydefkis Diamantis

The redox properties of two large DNA fragments composed of 39 base pairs, differing only by an 8-oxoguanine (8oxoG) defect replacing a guanine (G), were investigated in physiological conditions using mixed quantum mechanical/molecular mechanical (QM/MM) m ...

AMER CHEMICAL SOC2020

Establishing a Ternary System for Optical Monitoring of DNA-Protein Interactions with Single-Walled Carbon Nanotubes

Shang-Jung Wu

DNA-protein interactions lie at the crux of life's essential processes. As such, various technologies have been developed to characterize these interactions. The distinct advantages of these technologies can be leveraged to study different facets of these ...

EPFL2020

Innovative Techniques and Strategies for a Reliable High-Throughput Genotoxicity Assessment

Pauline Franz

Damage to DNA is a central mechanism to the initiation of carcinogenesis. As a consequence, precise DNA damage detection is essential for an effective risk assessment of xenobiotics and constitutes a powerful tool for human biomonitoring and early stage ca ...

AMER CHEMICAL SOC2020

Experimenting with knots

Giovanni Dietler

Knots are interesting objects to experiment since their topological properties are combined with mechanical properties, fluid mechanics or dynamical properties like unknotting under the excitation of the thermal energy. Knots play also a role in biology be ...

SPRINGER HEIDELBERG2019

Exploring on Protein-DNA interactions

Alexandra Styliani Kalantzi

A variety of DNA-binding proteins organizes the chromosomal DNA and regulates gene transcription, and DNA replication and recombination. In particular, for gene regulation there is a category of DNA-binding proteins, the transcription factors, which can de ...

EPFL2019

Engineering a stable future for DNA-origami as a biomaterial

Hale Bila, Maartje Martina Cornelia Bastings, Eva Eugene Kurisinkal

DNA as a biomaterial has evoked great interest as a potential platform for therapeutics and diagnostics and as hydrogel scaffolds due to the relative ease of programming its robust and uniform shape, site-specific functionality and controlled responsive be ...

ROYAL SOC CHEMISTRY2019

Neighbor predation linked to natural competence fosters the transfer of large genomic regions in Vibrio cholerae

Christian Iseli, Nicolas Jean Philippe Guex, Noémie Matthey, Melanie Blokesch, Candice Stoudmann, Sandrine Stutzmann

Natural competence for transformation is a primary mode of horizontal gene transfer. Competent bacteria are able to absorb free DNA from their surroundings and exchange this DNA against pieces of their own genome when sufficiently homologous. However, the ...

2019