1,721,120 research outputs found
Clay-based drug-delivery systems: what does the future hold?
No full textClays for drug delivery have been used from ancient time due to the large availability
of clay minerals and their unprecedented properties. The empirical use of nanoclays
from the past is converted in a stimulating scientific task aimed at building up
nanoarchitectonic vehicles for drug delivery in a targeted and stimuli-responsive
fashion. Here the historical aspects are discussed; next the modern examples of
applications of different clay-based materials are discussed. A special focus is given to
halloysite clay nanotubes, which are an emerging and very promising nanomaterial for
drug-delivery purposes due to its special morphology and unique chemical properties.
Advantages and limitations of these natural nanomaterials are critically discussed
pointing out the future perspectives and directions for further research
Nanocomposite based on Multi-Macrocyclic Receptors and Halloysite for Volatile Organic Compounds Capture
No full textVolatile organic compounds (VOCs) are chemicals released to the atmosphere by natural and anthropogenic sources. VOCs are hazardous air pollutants and promote formation of photochemical smog. Variety of chemicals released from pharmaceutical industry includes priority pollutants like benzene, toluene, and dichloromethane. The aim of this work was at designing, preparing and characterizing from the physico-chemical view-point a pseudo nano-sponge with low environmental impact for pollutant removal. As adsorbent material, a nanocomposite based on nanoclay and cucurbiturils, which are biocompatible materials, were investigated. Clay minerals (e.g. montmorillonite and kaolin) are important components of soils and sediments. Many have strong sorption affinities, large specific surface areas and high cation exchange capacities. These aluminosilicates have been tested since more than 40 years ago in the removal of toxic metals or organic pollutants. Among the aluminosilicates, halloysite (Al2Si2O5(OH)4 ·nH2O) is a special nano-geomaterial because of its tubular morphology, high porosity and tunable surface chemistry which enabled it to be utilized as a promising adsorbent for various organic pollutants. Cucurbiturils are cyclic polymers of glycourils which can exhibit similar host–guest chemistry as cyclodextrins. There are different homologues of cucurbiturils among which CB[8] selected in this work can hold small gas molecules, aliphatic and aromatic guests. The adsorption capability of hybrid nano-sponge was investigated and correlated to the structural feature of the adsorbent sustainable nanomaterial. Toluene was selected as contaminant prototyp
1,2,3-Oligotriazoles modified halloysite nanotubes as potential active biological species: synthesis and characterization
Full text linkIn the last years, the development of nano-formulations for cancer treatment represents one of the major
challenges of the scientific research. The prodrug strategy, that combines chemotherapeutic agents with
nanocarriers such as halloysite nanotubes (HNTs), is a promising strategy both to improve the biological
activity of the drug molecules and to reduce the side effects of drugs. Herein we report the synthesis and
characterization of a HNTs prodrug based on 1,2,3-triazole units covalently linked to HNTs external surface,
bearing different positively charged moieties, which could present interesting pharmacological activities
A competitive reactivity study on the oxidative cyclization of thiosemicarbazones into 1,3,4-thiadiazolidines
Full text linkAbstract
In order to obtain useful insights on the mechanism of formation of 2(3H)-imino-1,3,4-thiadiazoles by
oxidative cyclization of aldehyde thiosemicarbazones with Cu(II) or Fe(III) salts, a competitive reactivity study
was performed on a suitable set of diversely substituted substrates, by means of HPLC techniques. This
approach enabled to exploit Hammett’s equation without performing otherwise difficult-to-run kinetic
experiments. The results presented herein support the hypothesis that the formation of the thiadiazole ring is
induced by the attack of the oxidizing Lewis acid metal cation onto the imine-like nitrogen atom of the
thiosemicarbazone substrate. Beyond mechanistic interpretation, the paper particularly focuses onto the
methodological issues implied
Effects of solvent-free microwave extraction on the chemical composition of essential oil of Calamintha nepeta (L.) Savi compared with the conventional production method
No full textBiocompatible poly(N -isopropylacrylamide)-halloysite nanotubes for thermoresponsive curcumin release
No full textThe grafting of poly(N-isopropylacrylamide) (PNIPAAM) onto the halloysite external surface is proposed in order to obtain a novel thermoresponsive drug carrier for curcumin delivery. The new nanomaterial is characterized by means of FT-IR spectroscopy, thermogravimetric analysis, and SEM investigations. A high density of polymer chain was achieved at the nanoparticle surface. The PNIPAAM dehydration phenomenon was observed in water above 32 °C that is nearly coincident with the lower critical solution temperature for the polymer. The colloidal stability as well as the wettability of the obtained nanomaterial may be triggered by temperature stimuli. In vitro tests simulating the gastro-intestinal transit demonstrated that the proposed delivery system allows a targeted release of curcumin, preventing its degradation in an acidic medium. We synthesized a new hybrid nanoparticle that is very promising for several applications due to the copresence of a biocompatible region, to the temperature response, and to the hollow cavity, which can load active species
SYNTHESIS AND CHARACTERIZATION BY THERMOGRAVIMETRIC ANALYSIS OF A NEW DRUG DELIVERY SYSTEM BASED ON HALLOYSITE NANOTUBES
No full textCHEMICAL MODIFICATIONS OF HALLOYSITE NANOTUBES FOR THE DEVELOPMENT OF SMART NANOMATERIALS
No full textHalloysite nanoclays (HNTs) are promising nanomaterials because of their versatile properties, such as hollow tubular morphology and tunable surface chemistry. HNTs are biocompatible, no toxic and abundantly available at low cost. Due to these characteristics HNTs are suitable for development of hybrid sustainable materials, which are perspective for wastewater remediation, green packaging and drug delivery. HNTs are quite polydisperse in size with a length of ca. 1 m, while the external diameter and the lumen range between 50-80 nm and 10-15 nm, respectively. Chemically, halloysite is composed of gibbsite octahedral sheet (Al-OH) groups on the inner surface and siloxane (Si−O−Si) groups on the external surface. This different chemistry allows the selective modification of HNTs surfaces. We performed several chemical functionalization of HNTs materials to confer properties valuable in specific applications.
The HNTs inner lumen was modified to generate an hydrophobic microenvironment for the solubilization of compounds sparingly soluble in water (aromatic and aliphatic oils). Oppositely, the outer surface hydrophobization was employed to create reverse inorganic micelles to be used as dispersant for hydrophilic compounds (such as CuSO4·5H2O) in a confined environment within an organic solvent.
Grafting chemically modified cyclodextrin units onto the nanotube surface endowed to obtain a singular nanoparticle with double cavity (HNTs and cyclodextrin lumen). The obtained materials were characterized to investigate the structure and colloidal stability in aqueous dispersions. The grafted cyclodextrins were modified with thiosaccharide
pendants, to mimic the binding of sugars to proteins and the glyco-cluster effect for cellular recognition events. Drug-loading and delivery abilities were tested by using curcumin, a common naturally occurring anticancer agent
Metodo per la preparazione di nanocompositi antibatterici
No full textLa presente invenzione riguarda un materiale polimerico con proprietà antibatteriche e antifungine, detto materiale polimerico avente adeso sulla sua superficie un nanomateriale costituito da nanotubi di allosite (HNTs) antimicrobici. Un tale materiale polimerico antimicrobico/antifungino viene preparato attraverso l’applicazione di un metodo procedurale semplice ed economico. Oltre che l’evidente applicazione in campo biomedicale, le caratteristiche metodologiche di questa invenzione ne consentono la diffusione in vari ambiti applicativi comuni, come ad esempio l’active food packaging. Il trattamento proposto prevede 10 l’introduzione di una modifica solo superficiale del PVC e può quindi essere verosimilmente integrato in un processo produttivo come ultima fase di trattamento senza alterare gli stadi di processo precedenti
Co-loaded cardanol/triazole-halloysite system: characterization of the supramolecular complex and evaluation of its antiproliferative activity
No full textHalloysite nanotubes modified with triazolium salts
(f-HNT) were found to be
promising drug carriers for biological molecules [1
].
In this work we report data about f-HNT as carrier
for cardanol, a molecule with
interesting biological activity [2]. The interactio
n between cardanol and f-
HNT was highlighted by HPLC, FTIR spectroscopy, TGA
, water contact
angle measurements and SEM investigations.
Release of cardanol from the system and cytotoxic e
ffect of the complex f-
HNT/Card on hepatocarcinoma cell lines were, also,
evaluated. The obtained
results put forward the use of halloysite as drug c
arrie
- …
