Destabilizing Interactions in Human Telomeric G-Quadruplex Multimers.

G-Quadruplexes are secondary structures that may form in G-rich nucleic acid sequences. The extended overhang at the ends of human telomeres has the potential to form multiple G-Quadruplexes that are crucial in regulating key biological processes. Here, we employ small-angle X-ray scattering-guided extremely coarse-grained simulations to provide a picture of the arrangement of G-Quadruplexes in long telomeric sequences.

Polymeric Properties of Telomeric G-Quadruplex Multimers: Effects of Chemically Inert Crowders.

G-quadruplexes are noncanonical DNA structures rather ubiquitous in the human genome, which are thought to play a crucial role in the development of the majority of cancers. Here, we present a novel coarse-grained approach in modeling G-quadruplexes that accounts for their structural flexibility. We apply it to study the polymeric properties of G-quadruplex multimers, with and without crowder molecules, to mimic in vivo conditions.

Relating the length of a magnetic filament with solvophobic, superparamagnetic colloids to its properties in applied magnetic fields.

The idea of creating polymer-like structures by crosslinking magnetic nanoparticles (MNPs) opened an alternative perspective on controlling the rheological properties of magnetoresponsive systems, because unlike suspensions of self-assembled MNPs, whose cluster sizes are sensitive to temperature, magnetic filaments (MFs) preserve their initial topology. Considering the length scales characteristic of single-domain nanoparticles used to create MFs, the MNPs can be both ferro- and superparamagnetic. Moreover, steric or electrostatic stabilization might not fully screen van der Waals interactions.

Rheology of a Nanopolymer Synthesized through Directional Assembly of DNA Nanochambers, for Magnetic Applications.

We present a numerical study of the effects of monomer shape and magnetic nature of colloids on the behavior of a single magnetic filament subjected to the simultaneous action of shear flow and a stationary external magnetic field perpendicular to the flow. We find that based on the magnetic nature of monomers, magnetic filaments exhibit a completely different phenomenology. Applying an external magnetic field strongly inhibits tumbling only for filaments with ferromagnetic monomers.

Nanopolymers for magnetic applications: how to choose the architecture?

Directional assembly of nanoscale objects results in morphologies that can broadly be classified as supra-molecular nanopolymers. Such morphologies, given a functional choice of the monomers used as building blocks, can be of ubiquitous utility in optical, magnetic, rheological, and medical applications. These applications, however, require a profound understanding of the interplay between monomer shape and bonding on one side, and polymeric properties - on the other.

Divalent Multilinking Bonds Control Growth and Morphology of Nanopolymers.

Assembly of nanoscale objects into linear architectures resembling molecular polymers is a basic organization resulting from divalent interactions. Such linear architectures occur for particles with two binding patches on opposite sides, known as Janus particles. However, unlike molecular systems where valence bonds can be envisioned as pointlike interactions nanoscale patches are often realized through multiple molecular linkages.

Correction: Characterisation of the magnetic response of nanoscale magnetic filaments in applied fields.

Correction for 'Characterisation of the magnetic response of nanoscale magnetic filaments in applied fields' by Deniz Mostarac et al., Nanoscale, 2020, DOI: .

Characterisation of the magnetic response of nanoscale magnetic filaments in applied fields.

Incorporating magnetic nanoparticles (MNPs) within permanently crosslinked polymer-like structures opens up the possibility for synthesis of complex, highly magneto-responsive systems. Among such structures are chains of prealigned magnetic (ferro- or super-paramagnetic) monomers, permanently crosslinked by means of macromolecules, which we refer to as magnetic filaments (MFs). In this paper, using molecular dynamics simulations, we encompass filament synthesis scenarios, with a compact set of easily tuneable computational models, where we consider two distinct crosslinking approaches, for both ferromagnetic and super-paramagnetic monomers.