Biology subjects

Talbot, H.

Publications and source records attributed to Talbot, H..

7 recordsLinked to original sources

bioRxiv2026

Multi-dimensional DNA nanostructures isothermally assembled in hydrated ionic liquids

DNA nanostructures can be tailored to perform a wide variety of functions, with continued interest in biological applications. Some aspects of DNA nanostructure assembly can hinder the ability of nanostructures to be useful in physiological environments. Typical assembly methods employ magnesium ions to stabilize the structure, which leave the structure susceptible to damage by nucleases in body fluids. Further, DNA nanostructure assembly typically involves a thermal annealing protocol in which DNA strands are heated in a specific buffer to a high temperature and cooled slowly at specific rates, preventing convenient encapsulation of temperature-sensitive guest molecules. In this work, we demonstrate the assembly of a wide variety of DNA nanostructures and 3D crystals in a hydrated ionic liquid (choline dihydrogen phosphate, CDHP) instead of magnesium at constant moderate temperatures, thus avoiding thermal annealing. CDHP-assembled structures show enhanced biostability against a variety of nucleases. Molecular dynamics simulations show that choline ions stabilize DNA nanostructures by a direct and close-range interaction in contrast to the predominantly water-mediated interactions of Mg2+, leading to enhanced nuclease resistance in CDHP-containing environments. CDHP-assembled structures do not affect the viability of HepG2 cells and show higher cell internalization. Overall, this work develops a potential method to construct more biostable DNA nanostructures and 3D crystals in a simple one pot process. Assembly of DNA nanostructures under isothermal conditions is desirable for scaffolding biomolecules and to reduce the need for thermal annealing instruments, allowing nanostructure preparation in low-resource settings.

biophysics↗

bioRxiv2025

Paranemic cohesion of DNA molecules in different counter ions at room and physiological temperatures

Isothermal assembly allows the construction of DNA nanostructures at constant moderate temperatures. Further, assembly of DNA nanostructures in different counter ions expands their utility in various applications. In this work, we demonstrate the isothermal assembly of paranemic crossover (PX) DNA motifs in magnesium (Mg2+), calcium (Ca2+) and strontium (Sr2+) at 20 {degrees}C and 37 {degrees}C. Further, we study how differences in design affect the assembly of 4-stranded and 2-stranded PX molecules.

synthetic biology↗

bioRxiv2025

Peptide nucleic acid (PNA) and DNA hybrid three-way junctions and mesojunctions

Three-way junctions are simple and fundamental structural motifs that impart the typical branching property in most DNA nanostructures. While conventional three-way DNA junctions are well-known, mesojunctions are relatively unexplored. Here, we report the synthesis of peptide nucleic acid (PNA)/DNA hybrid three-way conventional and mesojunctions, containing a 14 bp duplex DNA arm and two PNA/DNA hybrid arms. We show that the PNA/DNA mesojunction can be assembled in magnesium-free buffers containing low concentrations of calcium or sodium salts. PNA/DNA hybrid junctions and mesojunctions showed higher thermal stability compared to the DNA versions. Further, PNA/DNA hybrid junctions assembled in sodium exhibited higher nuclease resistance against DNase I. Our results pave the way for PNA/DNA hybrid three-way junctions to be integrated into complex DNA nanostructure designs to improve their structural and enzymatic stability.

synthetic biology↗

bioRxiv2024

Influence of metal ions on the isothermal self-assembly of DNA nanostructures

DNA nanostructures are typically assembled by thermal annealing in buffers containing magnesium. We demonstrate the assembly of DNA nanostructures at constant temperatures ranging from 4 {degrees}C to 50 {degrees}C in solutions containing different metal ions. The choice of metal ions and the assembly temperature influence the isothermal assembly of several DNA motifs and designed three-dimensional DNA crystals. Molecular dynamics simulations show more fluctuations of the DNA structure in select monovalent ions (Na+ and K+) compared to divalent ions (Mg2+ and Ca2+). A key highlight is the successful assembly of DNA motifs in nickel-containing buffer at temperatures below 40 {degrees}C, otherwise unachievable at higher temperatures, or using an annealing protocol. DNA nanostructures isothermally assembled in different ions do not affect the viability of fibroblasts, myoblasts, and myotubes and or the immune response in myoblasts. The use of ions other than the typically-used magnesium holds key potential in biological and materials science applications that require minimal amounts of magnesium.

bioengineering↗

bioRxiv2023

Unusual Structural Properties of Switchback DNA

Synthetic DNA motifs form the basis of nucleic acid nanotechnology, and their biochemical and biophysical properties determine their applications. Here, we present a detailed characterization of switchback DNA, a globally left-handed structure composed of two parallel DNA strands. Compared to a conventional duplex, switchback DNA shows lower thermodynamic stability and requires higher magnesium concentration for assembly but exhibits enhanced biostability against some nucleases. Strand competition and strand displacement experiments show that component sequences have an absolute preference for duplex complements instead of their switchback partners. Further, we hypothesize a potential role for switchback DNA as an alternate structure in sequences containing short tandem repeats. Together with small molecule binding experiments and cell studies, our results open new avenues for switchback DNA in biology and nanotechnology.

bioengineering↗

bioRxiv2023

Self-assembly of DNA nanostructures in different cations

The programmable nature of DNA allows the construction of custom-designed static and dynamic nanostructures, and assembly conditions typically require high concentrations of magnesium ions which restricts their applications. In other solution conditions tested for DNA nanostructure assembly, only a limited set of divalent and monovalent ions have been used so far (typically Mg2+ and Na+). Here, we investigate the assembly of DNA nanostructures in a wide variety of ions using nanostructures of different sizes: a double-crossover motif (76 bp), a three-point-star motif ([~]134 bp), a DNA tetrahedron (534 bp) and a DNA origami triangle (7221 bp). We show successful assembly of a majority of these structures in Ca2+, Ba2+, Na+, K+ and Li+ and provide quantified assembly yields using gel electrophoresis and visual confirmation of a DNA origami triangle using atomic force microscopy. We further show that structures assembled in monovalent ions (Na+, K+ and Li+) exhibit up to a 10-fold higher nuclease resistance compared to those assembled in divalent ions (Mg2+, Ca2+ and Ba2+). Our work presents new assembly conditions for a wide range of DNA nanostructures with enhanced biostability.

synthetic biology↗

bioRxiv2020

ZeBraInspector, a whole organism screening platform enabling volumetric analysis of zebrafish brain white matter

In recent years, the zebrafish has become a well-established laboratory model. We describe here the ZeBraInspector (ZBI) platform for high-content 3D imaging (HCI) of 5 dpf zebrafish eleuthero-embryos (EEs). This platform includes a mounting method based on 3D-printed stamps to create a grid of wells in an agarose cast, facilitating batch acquisitions with a fast-confocal laser scanning microscope. We describe reference labeling in cleared fish with a fluorescent lipophilic dye. Based on this labeling, the ZBI software registers EE 3D images, making it possible to visualize numerous identically oriented EEs on a single screen, and to compare their morphologies and any fluorescent patterns at a glance. High-resolution 2D snapshots can be extracted. ZBI software is therefore useful for diverse high-content analyses (HCAs). Following automated segmentation of the lipophilic dye signal, the ZBI software performs volumetric analyses on whole EEs and their nervous system white matter. Through two examples, we illustrate the power of these analyses for obtaining statistically significant results from a small number of samples: the characterization of a phenotype associated with a neurodevelopmental mutation, and of the defects caused by treatments with a toxic anti-cancer compound.

neuroscience↗