A Smart DNA Tetrahedron That Isothermally Assembles or Dissociates in Response to the Solution pH Value Changes

This communication reports a DNA tetrahedron whose self-assembly is triggered by an acidic environment. The key element is the formation/dissociation of a short, cytosine (C)-containing, DNA triplex. As the solution pH value oscillates between 5.0 and 8.0, the DNA triplex will form and dissociate that, in turn, leads to assembly or disassembly of the DNA tetrahedron, which has been demonstrated by native polyacrylamide gel electrophoresis (PAGE). We believe that such environment-responsive behavior will be important for potential applications of DNA nanocages such as on-demand drug release

Artificial, Parallel, Left-Handed DNA Helices

This communication reports an engineered DNA architecture. It contains multiple domains of half-turn-long, standard B-DNA duplexes. While each helical domain is right-handed and its two component strands are antiparallel, the global architecture is left-handed and the two component DNA strands are oriented parallel to each other

DNA Nanostructures-Mediated Molecular Imprinting Lithography

This paper describes the fabrication of polymer stamps using DNA nanostructure templates. This process creates stamps having diverse nanoscale features with dimensions ranging from several tens of nanometers to micrometers. DNA nanostructures including DNA nanotubes, stretched λ-DNA, two-dimensional (2D) DNA brick crystals with three-dimensional (3D) features, hexagonal DNA 2D arrays, and triangular DNA origami were used as master templates to transfer patterns to poly­(methyl methacrylate) and poly­(l-lactic acid) with high fidelity. The resulting polymer stamps were used as molds to transfer the pattern to acryloxy perfluoropolyether polymer. This work establishes an approach to using self-assembled DNA templates for applications in soft lithography

Self-Assembly of Responsive Multilayered DNA Nanocages

Here we report the assembly of multilayered DNA nanocages. The layers can be separated in response to a chemical cue, ATP. This is an effort to increase the structural complexity of DNA nanocages. The structures have been characterized by native polyacrylamide gel electrophoresis, atomic force microscopy, and cryogenic electron microscopy. We envision that the layer-by-layer assembly strategy used in this study can be easily applied to other DNA nanocages to form Russian-doll-like semisolid structures, while the chemically activated layer separation makes a contribution to the development of “smart” DNA nanocages

Reversibly Switching the Surface Porosity of a DNA Tetrahedron

The ability to reversibly switch the surface porosity of nanocages would allow controllable matter transport in and out of the nanocages. This would be a desirable property for many technological applications, such as drug delivery. To achieve such capability, however, is challenging. Herein we report a strategy for reversibly changing the surface porosity of a self-assembled DNA nanocage (a DNA tetrahedron) that is based on DNA hydridization and strand displacement. The involved DNA nanostructures were thoroughly characterized by multiple techniques, including polyacrylamide gel electrophoresis, dynamic light scattering, atomic force microscopy, and cryogenic electron microscopy. This work may lead to the design and construction of stimuli-responsive nanocages that might find applications as smart materials

Retrosynthetic Analysis-Guided Breaking Tile Symmetry for the Assembly of Complex DNA Nanostructures

Current tile-based DNA self-assembly produces simple repetitive or highly symmetric structures. In the case of 2D lattices, the unit cell often contains only one basic tile because the tiles often are symmetric (in terms of either the backbone or the sequence). In this work, we have applied retrosynthetic analysis to determine the minimal asymmetric units for complex DNA nanostructures. Such analysis guides us to break the intrinsic structural symmetries of the tiles to achieve high structural complexities. This strategy has led to the construction of several DNA nanostructures that are not accessible from conventional symmetric tile designs. Along with previous studies, herein we have established a set of four fundamental rules regarding tile-based assembly. Such rules could serve as guidelines for the design of DNA nanostructures

A new glycoprotein SPG-8700 isolated from sweet potato with potential anti-cancer activity against colon cancer

<p>A new small molecule glycoprotein SPG-8700 with potential anti-colorectal cancer activity was firstly separated by tracking of bioactivity from a new sweet potato variety Zhongshu-1. Matrix-assisted laser desorption ionization mass spectrometry, high-performance liquid chromatography and amino acid analyzer were applied separately to determine the molecular weight and compositions of this glycoprotein. Flow cytometry analysis and western blotting analysis were employed to explore it’s mechanism of the anti-colorectal cancer. The molecular weight of glycoprotein was 8703.8D (SPG-8700). Relative sugar and protein contents in SPG-8700 were 73.4 and 26.6%, comprising more than 6 types of sugars (mannose, rhamnose, glucuronic acid, glucose, galactose and arabinose with a proportion of 1:6.9:7.3:1.5:46:21). Further results indicated that SPG-8700 promoted apoptosis in HCT-116 cells through regulating the expression of Bcl-2 and Bax and had no effect on the growth of normal cells.</p

Supra-Nanoparticle Functional Assemblies through Programmable Stacking

The quest for the by-design assembly of material and devices from nanoscale inorganic components is well recognized. Conventional self-assembly is often limited in its ability to control material morphology and structure simultaneously. Here, we report a general method of assembling nanoparticles in a linear “pillar” morphology with regulated internal configurations. Our approach is inspired by supramolecular systems, where intermolecular stacking guides the assembly process to form diverse linear morphologies. Programmable stacking interactions were realized through incorporation of DNA coded recognition between the designed planar nanoparticle clusters. This resulted in the formation of multilayered pillar architectures with a well-defined internal nanoparticle organization. By controlling the number, position, size, and composition of the nanoparticles in each layer, a broad range of nanoparticle pillars were assembled and characterized in detail. In addition, we demonstrated the utility of this stacking assembly strategy for investigating plasmonic and electrical transport properties

Supra-Nanoparticle Functional Assemblies through Programmable Stacking

The quest for the by-design assembly of material and devices from nanoscale inorganic components is well recognized. Conventional self-assembly is often limited in its ability to control material morphology and structure simultaneously. Here, we report a general method of assembling nanoparticles in a linear “pillar” morphology with regulated internal configurations. Our approach is inspired by supramolecular systems, where intermolecular stacking guides the assembly process to form diverse linear morphologies. Programmable stacking interactions were realized through incorporation of DNA coded recognition between the designed planar nanoparticle clusters. This resulted in the formation of multilayered pillar architectures with a well-defined internal nanoparticle organization. By controlling the number, position, size, and composition of the nanoparticles in each layer, a broad range of nanoparticle pillars were assembled and characterized in detail. In addition, we demonstrated the utility of this stacking assembly strategy for investigating plasmonic and electrical transport properties

Table_1_The causal effect of HbA1c on white matter brain aging by two-sample Mendelian randomization analysis.XLSX

BackgroundPoor glycemic control with elevated levels of hemoglobin A1c (HbA1c) is associated with increased risk of cognitive impairment, with potentially varying effects between sexes. However, the causal impact of poor glycemic control on white matter brain aging in men and women is uncertain.MethodsWe used two nonoverlapping data sets from UK Biobank cohort: gene-outcome group (with neuroimaging data, (N = 15,193; males/females: 7,101/8,092)) and gene-exposure group (without neuroimaging data, (N = 279,011; males/females: 122,638/156,373)). HbA1c was considered the exposure and adjusted “brain age gap” (BAG) was calculated on fractional anisotropy (FA) obtained from brain imaging as the outcome, thereby representing the difference between predicted and chronological age. The causal effects of HbA1c on adjusted BAG were studied using the generalized inverse variance weighted (gen-IVW) and other sensitivity analysis methods, including Mendelian randomization (MR)-weighted median, MR-pleiotropy residual sum and outlier, MR-using mixture models, and leave-one-out analysis.ResultsWe found that for every 6.75 mmol/mol increase in HbA1c, there was an increase of 0.49 (95% CI = 0.24, 0.74; p-value = 1.30 × 10−4) years in adjusted BAG. Subgroup analyses by sex and age revealed significant causal effects of HbA1c on adjusted BAG, specifically among men aged 60–73 (p-value = 2.37 × 10−8).ConclusionPoor glycemic control has a significant causal effect on brain aging, and is most pronounced among older men aged 60–73 years, which provides insights between glycemic control and the susceptibility to age-related neurodegenerative diseases.</p