Search results for "nanostructures"

Computational Study of Nanosized Drug Delivery from Cyclodextrins, Crown Ethers and Hyaluronan in Pharmaceutical Formulations

2015

Abstract The problem in this work is the computational characterization of cyclodextrins, crown ethers and hyaluronan (HA) as hosts of inclusion complexes for nanosized drug delivery vehicles in pharmaceutical formulations. The difficulty is addressed through a computational study of some thermodynamic, geometric and topological properties of the hosts. The calculated properties of oligosaccharides of D-glucopyranoses allow these to act as co-solvents of polyanions in water. In crown ethers, the central channel is computed. Mucoadhesive polymer HA in formulations releases drugs in mucosas. Geometric, topological and fractal analyses are carried out with code TOPO. Reference calculations are…

Carbohydrate nanocarriers in biomedical applications: functionalization and construction

2015

The specific targeting of either tumor cells or immune cells in vivo by carefully designed and appropriately surface-functionalized nanocarriers may become an effective therapeutic treatment for a variety of diseases. Carbohydrates, which are prominent biomolecules, have shown their outstanding ability in balancing the biocompatibility, stability, biodegradability, and functionality of nanocarriers. The recent applications of sugar (mono/oligosaccharides and/or polysaccharides) for the development of nanomedicines are summarized in this review, including the application of carbohydrates for the surface-functionalization of various nanocarriers and for the construction of the nanocarrier its…

Racemic and Optically Pure Heptahelicene-2-carboxylic Acid: Its Synthesis and Self-Assembly into Nanowire-Like Aggregates

2010

Heptahelicene-2-carboxylic acid was effectively synthesised from suitably functionalised naphthalene building blocks. Methoxy-substituted 1,1'-ethyne-1,2-diylbis(2-but-3-yn-1-ylnaphthalene) was cyclised in the presence of CpCo(CO)(2)/PPh(3) to 2-methoxy-7,8,11,12-tetrahydroheptahelicene, which was converted into heptahelicen-2-yl trifluoromethanesulfonate. This reactive intermediate underwent Pd(OAc)(2)/dppp-catalysed methoxycarbonylation reaction to provide, after hydrolysis, heptahelicene-2-carboxylic acid. The racemate was resolved into enantiomers by semipreparative HPLC on a chiral column. The helicity of (+)-(P)-heptahelicene-2-carboxylic acid was assigned by correlating its CD spectr…

Hydrogen peroxide sensing with horseradish peroxidase-modified polymer single conical nanochannels.

2011

Inspired from the funtioning and responsiveness of biological ion channels, researchers attempt to develop biosensing systems based on polymer and solid-state nanochannels. The applicability of these nanochannels for detection/sensing of any foreign analyte in the surrounding environment depends critically on the surface characteristics of the inner walls. Attaching recognition sites to the channel walls leads to the preparation of sensors targeted at a specific molecule. There are many nanochannel platforms for the detection of DNA and proteins, but only a few are capable of detecting small molecules. Here, we describe a nanochannel platform for the detection of hydrogen peroxide, H(2)O(2)…

Self-Assembled DNA-Based Structures for Nanoelectronics

2023

Recent developments in structural DNA nanotechnology have made com-plex and spatially exactly controlled self-assembled DNA nanoarchitectureswidely accessible. The available methods enable large variety of differ-ent possible shapes combined with the possibility of using DNA structuresas templates for high-resolution patterning of nano-objects, thus openingup various opportunities for diverse nanotechnological applications. TheseDNA motifs possess enormous possibilities to be exploited in realization ofmolecular scale sensors and electronic devices, and thus, could enable fur-ther miniaturization of electronics. However, there are arguably two mainissues on making use of DNA-based electroni…

Reconfigurable DNA Origami Nanocapsule for pH-Controlled Encapsulation and Display of Cargo

2019

DNA nanotechnology provides a toolbox for creating custom and precise nanostructures with nanometer-level accuracy. These nano-objects are often static by nature and serve as versatile templates for assembling various molecular components in a user-defined way. In addition to the static structures, the intrinsic programmability of DNA nanostructures allows the design of dynamic devices that can perform predefined tasks when triggered with external stimuli, such as drug delivery vehicles whose cargo display or release can be triggered with a specified physical or chemical cue in the biological environment. Here, we present a DNA origami nanocapsule that can be loaded with cargo and reversibl…

Catalytic activity of palladium-based nanostructures in the conversion of simple olefinic hydro- and chlorohydrocarbons from first principles

2011

The interplay between cooperativity and diversity in model threshold ensembles

2014

The interplay between cooperativity and diversity is crucial for biological ensembles because single molecule experiments show a significant degree of heterogeneity and also for artificial nanostructures because of the high individual variability characteristic of nanoscale units. We study the cross-effects between cooperativity and diversity in model threshold ensembles composed of individually different units that show a cooperative behaviour. The units are modelled as statistical distributions of parameters (the individual threshold potentials here) characterized by central and width distribution values. The simulations show that the interplay between cooperativity and diversity results …

Glyphosate Sensor Based on Nanostructured Water-Gated CuO Field-Effect Transistor

2022

This research presents a comparative analysis of water-gated thin film transistors based on a copper oxide (CuO) semiconductor in the form of a smooth film and a nanostructured surface. A smooth CuO film was deposited through reactive magnetron sputtering followed by annealing in atmosphere at a temperature of 280 (Formula presented.) C. Copper oxide nanostructures were obtained by hydrothermal synthesis on a preliminary magnetron sputtered 2 nm thick CuO precursor followed by annealing at 280 (Formula presented.) C. An X-ray diffraction (XRD) analysis of the samples revealed the presence of a tenorite (CuO) phase with a predominant orientation of (002). Scanning electron microscopy (SEM) a…

Near-Infrared-Responsive Choline-Calix[4]arene-Gold Nanostructures for Potential Photothermal Cancer Treatment

2022

The development of novel chemical approaches for the fabrication of gold nanostructures with localized surface plasmon resonance (LSPR) falling in the near-infrared (NIR) region is one challenging topic in nanomaterials science. Due to their optical and photothermal properties triggered by light excitation in the therapeutic window (λmax = 650-1300 nm), gold-based nanostructures are appealing candidates in anticancer nanomedicine. Here, we report a novel method to prepare water-dispersible gold nanostructures with NIR-LSPR (λmax = 600-1000 nm) properties. The gold nanostructures were achieved in a single step by an unconventional method using NADH as a reducing agent and an amphiphilic chol…