Search results for "nanoparticle"

A l-glutamate-responsive delivery system based on enzyme-controlled self-immolative arylboronate-gated nanoparticles

2019

We report herein a L-glutamate (L-Glu)-responsive delivery system. It consists of Janus Au–mesoporous silica (MS) nanoparticles functionalized with L-glutamate oxidase on the Au face and with self-immolative arylboronate derivatives as caps on the MS face. The MS face is additionally loaded with a cargo. The delivery paradigm is based on the recognition of L-Glu by the enzyme and the subsequent formation of H2O2, which induces the cleavage of the self-immolative gate and the uncapping of the pores. Given the importance of L-Glu as a key neurotransmitter, we hope that these findings will help in designing new therapeutic strategies for nervous system diseases.

Nanoparticles as Enzyme Mimics

2013

Frontispiece: A Step into the Future: Applications of Nanoparticle Enzyme Mimics

2018

Space Charge Dynamics in Nanostructured Epoxy Resin

2008

The results of a comparative analysis performed on specimens of nanostructured epoxy resins obtained by different filler concentrations are reported in this paper. The specimens were prepared by dispersion of bohemite nanoparticles into a cycloaliphatic epoxy resin cross linked under UV. Dielectric properties, in particular space charge accumulation, are measured as a function of nanofiller content. Results indicate that space charge build up and charge mobility are affected largely by filler content. Concentrations of nanofiller of 5-7 wt% show a significant decrease of the space charge with respect to the base epoxy-resin and an increased mobility of negative carriers .

Triboelectrification of nanocomposites using identical polymer matrixes with different concentrations of nanoparticle fillers

2021

In this study, we investigate triboelectrification in polymer-based nanocomposites using identical polymer matrixes containing different concentrations of nanoparticles (NPs). The triboelectric surface charge density on polymer layers increased as the difference in nanoparticle filler concentration between the two triboelectric layers escalated, despite the fact that the polymer matrix was the same in both layers. This effect was observed in tests of various polymer types and filler NPs. Our mechanical experiments and finite element analysis simulations confirmed that polymeric triboelectrification is related to the surface viscoelastic deformation that occurs during mechanical contact and …

Multifunctional polymer-derivatized γ-Fe2O3 nanocrystals as a methodology for the biomagnetic separation of recombinant His-tagged proteins

2008

Abstract Multifunctional polymer-derivatized superparamagnetic iron oxide (γ-Fe2O3) nanoparticles were prepared for biomagnetic separation of histidine-tagged recombinant proteins building up a faster and efficient method for protein separation by making use of their intrinsic magnetic properties. Using polymer bound γ-Fe2O3 nanocrystals, a 6× histidine-tagged recombinant protein (silicatein) with a molecular weight of 24 kDa has been isolated and purified. The supermagnetic iron oxide nanocrystals were characterized by transmission electron microscopy (TEM), high-resolution TEM (HRTEM), SQUID and Mossbauer and the polymer functionalization of the γ-Fe2O3 nanocrystals was monitored by UV–vi…

A Step into the Future: Applications of Nanoparticle Enzyme Mimics.

2018

We describe elementary concepts, up-to-date developments, and perspectives of the emerging field of nanoparticle enzyme mimics (so-called "nanozymes") at the interface of chemistry, biology, materials, and nanotechnology. The design and synthesis of functional enzyme mimics is a long-standing goal of biomimetic chemistry. Metal complexes, polymers and engineered biomolecules capturing the structure of natural enzymes or their active centers have been made to achieve high rates and enhanced selectivities. Still, the design of new "artificial enzymes" that are not related to proteins but with capacity of production and stability at industrial level, remains a goal. Inorganic nanoparticles bea…

Interactions Between Blood Proteins and Nanoparticles Investigated Using Molecular Dynamics Simulations

2019

In the development of new therapeutic agents based on nanoparticles it is of fundamental importance understanding how these substances interact with the underlying biological milieu. Our research is focussed on simulating in silico these interactions using accurate atomistic models, and gather from these information general pictures and simplified models of the underlying phenomena. Here we report results about the interactions of blood proteins with promising hydrophilic polymers used for the coating of therapeutic nanoparticles, about the salt dependent behavior of one of these polymers (poly-(ethylene glycol)) and about the interactions of blood proteins with silica, one of the most used…

Optical properties of different polymer thin films containing in situ synthesized Ag and Au nanoparticles

2009

Here we report on the in situ synthesis of Ag and Au nanoparticles inside several polymer matrixes by solid-state chemical reduction of a metallic salt. Poly(ethyleneimine) (PEI), poly(hydroxyethyl methacrylate) (PHEMA), poly(vinylpyrrolidone) (PVP), novolak, poly(4-vinylphenol) (P4VP), poly(4-vinylphenol)-co-(methyl methacrylate) (P4VP-co-MMA) and poly(styrene-co-allyl alcohol) (PS-co-AA) were able to reduce Ag(I) and Au(III) to the corresponding nanoparticles during the baking process. The nanoparticle diameters of Ag and Au were found to range from 2 to 25 nm. TEM also indicated a uniform distribution of nanoparticles embedded in the thin film. This approach is suitable for controlling t…

Maghemite polymer nanocomposites with modulated magnetic properties

2007

A method is presented for the production of maghemite polymer nanocomposites with modulated magnetic properties. Magnetic nanocomposites prepared using this method show regular variation in the magnetic blocking temperature from 2 K to 300 K, and variation in the saturation magnetization from 0 to 50 emu g � 1 (Fe2O3). The method is based on the in situ formation of maghemite nanoparticles in nitrogen-base polymer matrixes. The particle size can be varied regularly from 1.5 nm to 16 nm by changing the ratio of iron loading in the polymer and/or the Fe(II)/Fe(III) ratios. The particles are isolated and uniformly distributed within the matrix. The mate