Effect of Cannabis Smoke Condensate on C. albicans Growth and Biofilm Formation.

The most common use of cannabis is smoking. The oral ecosystem, among other constituents, can be deregulated by the presence of cannabis smoke in the oral cavity. We evaluated the effect of cannabis smoke condensate (CSC) on the behavior of Candida albicans, a common yeast found in the oral cavity. The yeast was first cultured with different concentrations of CSC, and its growth was evaluated. The transition from the blastospore to the hyphal form and the hyphae size were assessed after 3 and 6 h, along with biofilm formation after 72 h of contact with CSC. The response of C. albicans to oxidative (H2O2) stress was also examined. Our results show that CSC contained high amounts of THC (about 1055 ppm), CBN (63 ppm), and CBG (about 47 ppm). The presence of various concentrations of CSC in the culture medium increased C. albicans growth. CSC also contributed to increases in both the hyphal length and biofilm mass. Following oxidative stress (H2O2 at either 100 or 500 µM), CSC prevented the damaging effect of H2O2 on both C. albicans shape and growth. These findings support clinical observations demonstrating that cannabis may promote C. albicans growth and oral candidiasis.

Sequential delivery of synergistic drugs by silica nanocarriers for enhanced tumour treatment.

Herein hybrid silica nanoparticles have been engineered to direct the sequential delivery of multiple chemotherapeutic drugs in response to external stimuli such as variations in pH. The nanocarriers consist of conventional MCM-41-type nanoparticles, which have been functionalised with an organic ligand (or stalk) grafted onto the external surface. The stalk is designed to "recognise" a complementary molecule, which serves as a "cap" to block the pores of the nanoparticles. First, camptothecin is introduced into the pores by diffusion prior to capping the pore apertures via molecular recognition. The cap, which is a derivative of 5-fluorouracil, serves as a second cytotoxic drug for synergistic chemotherapy. In vitro tests revealed that negligible release of the drugs occurred at pH 7.4, thus avoiding toxic side effects in the blood stream. In contrast, the stalk/cap complex is destabilised within the endolysosomal compartment (pH 5.5) of cancer cells, where release of the drugs was demonstrated. Furthermore, this environmentally responsive system exhibited a synergistic effect of the two drugs, where the pH-triggered release of the cytotoxic cap followed by diffusion-controlled release of the drug cargo within the pores led to essentially complete elimination of breast cancer cells.

Selective Separation and Preconcentration of Scandium with Mesoporous Silica.

Separation and preconcentration of scandium (Sc) were successfully achieved using a mesoporous silica support that showed good selectivity for this element. Unmodified mesoporous silica materials were used as an extracting medium in a solid-liquid extraction (SLE) process. Selectivity, extraction capacity, kinetics of extraction, and reusability under acidic conditions were investigated. The results demonstrate the potential of unmodified mesoporous silica materials for the selective separation and preconcentration of Sc. As no chelating ligand was grafted on the silica surface, which is often the case for most solid-phase extraction media for metal-ion separation, the experimental data allow us to hypothesize that the accessible silanols on the material surface are responsible for the selective Sc extraction. This interesting feature would drastically decrease the cost of solid-liquid extraction systems by using unmodified mesoporous silica materials. Moreover, a leachate solution obtained from a real rare-earth element ore was used to determine the performances of the proposed materials in a packed column configuration. The maximum Sc adsorption on the silica material surfaces is moderate (1 mg/g), but it is balanced by a great concentration factor (more than 100 times). The extraction performances are potentially promising, both in terms of selectivity and preconcentration, under the acidic conditions tested.

Functionalization of Mesoporous Carbon Materials for Selective Separation of Lanthanides under Acidic Conditions.

New functional mesoporous carbon sorbents were successfully synthesized to overcome some issues of solid-liquid extraction (e.g., selectivity, extraction capacity, and reusability under acidic conditions) in production of pure lanthanides (Ln). Wet-oxidation technique was performed to increase the surface reactivity of pristine ordered mesoporous carbon (OMC), and, in a second step, a surface modification using diglycolamide-based (DGA-based) selective ligands toward Ln was performed. Two types of ligands were tested: the first contains a long spacer (e.g., between carbon support and chelating function), and the second has a shorter one. These materials have been characterized by X-ray photoelectron spectroscopy (XPS), low-angle X-ray diffraction (XRD), thermogravimetric analysis, nitrogen sorption, transmission electron microscopy (TEM), and scanning electron microscopy (SEM). These analyses confirmed that the carbon mesostructure was maintained after organo-functionalization of the surface and showed the covalent attachment of selective ligands. These new materials, and especially the system with a short spacer between the ligand and the surface, reveal unique Ln selectivity profiles with improved extraction performances for the recovery of lanthanides, in terms of both selectivity and adsorption capacity, and unprecedented stability under acidic conditions.

Functionalization of mesoporous materials for lanthanide and actinide extraction.

Among the energy sources currently available that could address our insatiable appetite for energy and minimize our CO2 emission, solar, wind, and nuclear energy currently occupy an increasing portion of our energy portfolio. The energy associated with these sources can however only be harnessed after mineral resources containing valuable constituents such as actinides (Ac) and rare earth elements (REEs) are extracted, purified and transformed into components necessary for the conversion of energy into electricity. Unfortunately, the environmental impacts resulting from their manufacture including the generation of undesirable and, sometimes, radioactive wastes and the non-renewable nature of the mineral resources, to name a few, have emerged as challenges that should be addressed by the scientific community. In this perspective, the recent development of functionalized solid materials dedicated to selective elemental separation/pre-concentration could provide answers to several of the above-mentioned challenges. This review focuses on recent advances in the field of mesoporous solid-phase (SP) sorbents designed for REEs and Ac liquid-solid extraction. Particular attention will be devoted to silica and carbon sorbents functionalized with commonly known ligands, such as phosphorus or amide-containing functionalities. The extraction performances of these new systems are discussed in terms of sorption capacity and selectivity. In order to support potential industrial applications of the silica and carbon-based sorbents, their main drawbacks and advantages are highlighted and discussed.

Mesoporous-Silica-Functionalized Nanoparticles for Drug Delivery.

The ever-growing interest for finding efficient and reliable methods for treatment of diseases has set a precedent for the design and synthesis of new functional hybrid materials, namely porous nanoparticles, for controlled drug delivery. Mesoporous silica nanoparticles (MSNPs) represent one of the most promising nanocarriers for drug delivery as they possess interesting chemical and physical properties, thermal and mechanical stabilities, and are biocompatibile. In particular, their easily functionalizable surface allows a large number of property modifications further improving their efficiency in this field. This Concept article deals with the advances on the novel methods of functionalizing MSNPs, inside or outside the pores, as well as within the walls, to produce efficient and smart drug carriers for therapy.

A designed 5-fluorouracil-based bridged silsesquioxane as an autonomous acid-triggered drug-delivery system.

Two new prodrugs, bearing two and three 5-fluorouracil (5-FU) units, respectively, have been synthesized and were shown to efficiently treat human breast cancer cells. In addition to 5-FU, they were intended to form complexes through H-bonds to an organo-bridged silane prior to hydrolysis-condensation through sol-gel processes to construct acid-responsive bridged silsesquioxanes (BS). Whereas 5-FU itself and the prodrug bearing two 5-FU units completely leached out from the corresponding materials, the prodrug bearing three 5-FU units was successfully maintained in the resulting BS. Solid-state NMR ((29) Si and (13) C) spectroscopy show that the organic fragments of the organo-bridged silane are retained in the hybrid through covalent bonding and the (1) H NMR spectroscopic analysis provides evidence for the hydrogen-bonding interactions between the prodrug bearing three 5-FU units and the triazine-based hybrid matrix. The complex in the BS is not affected under neutral medium and operates under acidic conditions even under pH as high as 5 to deliver the drug as demonstrated by HPLC analysis and confirmed by FTIR and (13) C NMR spectroscopic studies. Such functional BS are promising materials as carriers to avoid the side effects of the anticancer drug 5-FU thanks to a controlled and targeted drug delivery.