Search results for "Lease"

An Overview of Functionalized Graphene Nanomaterials for Advanced Applications

2021

Interest in the development of graphene-based materials for advanced applications is growing, because of the unique features of such nanomaterials and, above all, of their outstanding versatility, which enables several functionalization pathways that lead to materials with extremely tunable properties and architectures. This review is focused on the careful examination of relationships between synthetic approaches currently used to derivatize graphene, main properties achieved, and target applications proposed. Use of functionalized graphene nanomaterials in six engineering areas (materials with enhanced mechanical and thermal performance, energy, sensors, biomedical, water treatment, and c…

A synergic nanoantioxidant based on covalently modified halloysite–trolox nanotubes with intra-lumen loaded quercetin

2016

We describe the preparation and properties of the first example of a synergic nanoantioxidant, obtained by different functionalizations of the external surface and the inner lumen of halloysite nanotubes (HNTs). Trolox, a mimic of natural α-tocopherol, was selectively grafted on the HNT external surface; while quercetin, a natural polyphenolic antioxidant, was loaded into the inner lumen to afford a bi-functional nanoantioxidant, HNT–Trolox/Que, which was investigated for its reactivity with transient peroxyl radicals and a persistent 1,1-diphenyl-2-picrylhydrazyl (DPPH˙) radical in comparison with the corresponding mono-functional analogues HNT–Trolox and HNT/Que. Both HNT–Trolox and HNT/Q…

Covalently modified halloysite clay nanotubes: synthesis, properties, biological and medical applications

2017

Halloysite (HNT) is a promising natural nanosized tubular clay mineral that has many important uses in different industrial fields. It is naturally occurring, biocompatible, and available in thousands of tons at low cost. As a consequence of a hollow cavity, HNT is mainly used as nanocontainer for the controlled release of several chemicals. Chemical modification of both surfaces (inner lumen and outer surface) is a strategy to tune the nanotube's properties. Specifically, chemical modification of HNT surfaces generates a nanoarchitecture with targeted affinity through outer surface functionalization and drug transport ability from functionalization of the nanotube lumen. The primary focus …

INJECTABLE HYDROGEL BASED ON A NOVEL AMPHIPHILIC HYALURONIC ACID DERIVATIVE FOR CONTROLLED DRUG RELEASE

2015

A chitosan/silica hybrid 3D scaffold for simultaneous entrapment of two different hydrophilic substances

2022

We report the preparation of a hybrid chitosan/silica three-dimensional (3D) scaffold loaded simultaneously with two model hydrophilic substances, ibuprofen sodium salt and erioglaucine disodium salt. The first substance is entrapped in situ during the preparation of chitosan submillimetric beads by ionotropic gelation with sodium triphosphate, while the latter is post-loaded during the scaffold formation. Controlled release experiments carried out under neutral conditions demonstrate that the presence of nanostructured silica within the polymer matrix retards the release of both hydrophilic substances and increases the structure stability of the scaffold. Release profiles can be fitted to …

Salt release monitoring with specific sensors in "in vitro" oral and digestive environments from soft cheeses

2012

International audience; The objective of the present work is to demonstrate the interest and the feasibility of the measurement of NaCl concentrations in soft cheeses and in particular an in vitro digestion process by the use of chemical sensors. The analyzed matrices were the commercial Italian mozzarella cheeses and domestic cheese base models. The classification of mozzarellas was performed according to their salinity, while the breakdown of cheese base models has been followed both at initial steps of digestion in artificial mouth dispositive mimicking the oral sphere and in a gut-imitating digester (TIM-1). During the breakdown of soft cheese in the digester, the estimated values for N…

Incorporation of dynamic boronate links and Ag nanoparticles into PVA hydrogels for pH-Regulated and prolonged release of methotrexate

2021

Abstract In this study, pH-responsive hydrogels based on PVA-boronate crosslinks were prepared via a simple route and used for controlled and targeted delivery of anticancer drug methotrexate. A double network (DN) hydrogel composed of didiol-boronate/PVA complex as the first network and PVA crystallites generated by a freeze-thaw process as the second one was developed. The swelling of PVA-boronate DN hydrogels demonstrated high sensitivity to multiple stimuli including the pH, temperature, and ionic strength of the media thanks to the dynamic boronate links in the first network. Moreover, unlike previously reported hydrogels based on the boronate linkages, the new DN hydrogels preserved t…

EPR DOSIMETRY IN A MIXED NEUTRON AND GAMMA RADIATION FIELD

2004

Suitability of Electron Paramagnetic Resonance (EPR) spectroscopy for criticality dosimetry was evaluated for tooth enamel, mannose and alanine pellets during the 'international intercomparison of criticality dosimetry techniques' at the SILENE reactor held in Valduc in June 2002, France. These three materials were irradiated in neutron and gamma-ray fields of various relative intensities and spectral distributions in order to evaluate their neutron sensitivity. The neutron response was found to be around 10% for tooth enamel, 45% for mannose and between 40 and 90% for alanine pellets according their type. According to the IAEA recommendations on the early estimate of criticality accident a…

INULIN-BASED HYDROGELS: RHEOLOGICAL EVALUATION AND IN VITRO DRUG RELEASE STUDIES

2012

Halloysite Nanotubes Coated by Chitosan for the Controlled Release of Khellin

2020

In this work, we have developed a novel strategy to prepare hybrid nanostructures with controlled release properties towards khellin by exploiting the electrostatic interactions between chitosan and halloysite nanotubes (HNT). Firstly, khellin was loaded into the HNT lumen by the vacuum-assisted procedure. The drug confinement within the halloysite cavity has been proved by water contact angle experiments on the HNT/khellin tablets. Therefore, the loaded nanotubes were coated with chitosan as a consequence of the attractions between the cationic biopolymer and the halloysite outer surface, which is negatively charged in a wide pH range. The effect of the ionic strength of the aqueous medium…