Search results for "Silica nanoparticle"
showing 10 items of 59 documents
Finely Tuned Temperature-Controlled Cargo Release Using Paraffin-Capped Mesoporous Silica Nanoparticles
2011
[EN] Trapped: Mesoporous silica nanoparticles were loaded with a fluorescent guest and functionalized with octadecyltrimethoxysilane. The alkyl chains interact with paraffins, which build a hydrophobic layer around the particle (see picture). Upon melting of the paraffin, the guest molecule is released, as demonstrated in cells for the guest doxorubicin. The release temperature can be tuned by choosing an appropriate paraffin. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Nanoparticles coated by chloramphenicol in hydrogels as a useful tool to increase the antibiotic release and antibacterial activity in dermal drug de…
2023
Abstract Background Nanocarriers for antibacterial drugs became hopeful tools against the increasing resistance of bacteria to antibiotics. This work focuses on a comprehensive study of the applicability and therapeutic suitability of dermal carbopol-based hydrogels containing chloramphenicol carried by various nanoparticles (AuNPs and SiNPs). Methods The different forms of carbopol-based drugs for dermal use were obtained. Five different concentrations of chloramphenicol and two types of nanoparticles (silica and gold) in carbopol-based ointments were tested. The influence of different carbopol formulations with nanocarriers on the rheological properties as well as the release profile of a…
Diffusive equilibrium properties of O2 in amorphous SiO2 nanoparticles probed via dependence of concentration on size and pressure
2014
An experimental study on the diffusive equilibrium value of interstitial O2 in silica nanoparticles was carried out on samples with average particles diameter 40, 14, and 7 nm. The investigation was performed by measuring the concentration of interstitial O2 by Raman and photoluminescence techniques. The dependence of diffusive equilibrium concentration on pressure and temperature was investigated in the pressure range from 0.2 to 76 bar and in the temperature range from 98 to 244 °C. The equilibrium concentration of interstitial O2 follows Henry’s law at pressures below 13 bar whereas a departure from this model is observed at higher pressures. In particular, O2 concentration saturates abo…
Effects induced by UV laser radiation on the blue luminescence of silica nanoparticles
2013
The effects induced on the blue luminescence centered around 2.8 eV, characteristic of silica nanoparticles, were investigated by monitoring its intensity during and after exposure to the third and the fourth harmonic of a Nd:YAG pulsed laser. The luminescence trend is found to be dependent on the UV photon energy: 3.50 eV photons induce a partial bleaching followed by a recovery in the post-irradiation stage; 4.66 eV photons cause a total bleaching permanent after the irradiation. These results are interpreted as the conversion of luminescent defects towards stable and metastable configurations.
SURFACE MODIFICATION OF EAA WITH FUNCTIONALIZED SILICA NANOPARTICLES
2009
Nanosensor for Sensitive Detection of the New Psychedelic Drug 25I-NBOMe.
2020
[EN] This work reports the synthesis, characterization, and sensing behavior of a hybrid nanodevice for the detection of the potent abuse drug 25I-NBOMe. The system is based on mesoporous silica nanoparticles, loaded with a fluorescent dye, functionalized with a serotonin derivative and capped with the 5-HT2A receptor antibody. In the presence of 25I-NBOMe the capping antibody is displaced, leading to pore opening and rhodamine B release. This delivery was ascribed to 5-HT2A receptor antibody detachment from the surface due to its stronger coordination with 25I-NBOMe present in the solution. The prepared nanodevice allowed the sensitive (limit of detection of 0.6 mm) and selective recogniti…
A Biocatalytic Nanomaterial for the Label-Free Detection of Virus-Like Particles
2017
International audience; The design of nanomaterials that are capable of specific and sensitive biomolecular recognition is an on-going challenge in the chemical and biochemical sciences. A number of sophisticated artificial systems have been designed to specifically recognize a variety of targets. However, methods based on natural biomolecular detection systems using antibodies are often superior. Besides greater affinity and selectivity, antibodies can be easily coupled to enzymatic systems that act as signal amplifiers, thus permitting impressively low detection limits. The possibility to translate this concept to artificial recognition systems remains limited due to design incompatibilit…
Defect-related visible luminescence of silica nanoparticles
2013
The high photon emissivity in the visible spectral range is one of the most relevant phenomena emerging from the reduction of silica down to nanoscale; hence it is promising for the development of optical nanotechnologies (down converter, probes, display). It is well accepted that the origin of this luminescence is related to the high specific surface (~100 m2/g) that favors the formation of optically active defects at the nanosilica surface. With the aim to clarify the role of specific luminescent defects, here we report a detailed study of spectral and decay features by time-resolved photoluminescence spectra under a visible-UV tunable laser excitation. Our study is carried out on differe…