Dendritic Fibrous Colloidal Silica Internally Cross-linked by Bivalent Organic Cations: An Efficient Support for Dye Removal and the Reduction of Nitrobenzene Derivatives.

We designed a new unique amphoteric monodisperse colloid with a large complex internal structure, in which silica surfaces are bridged with an organic cross-linker. The rationale was that such colloids would be excellent adsorbents for cationic and anionic dyes and, when doped with noble metal nanoparticles, would be an excellent catalyst for the reduction of a variety of organic compounds. In the first step, the organo-silica bridging agent (bivalent organic cross-linkers) DABCO-S (silanated DABCO) was prepared through a simple nucleophilic substitution reaction between (3-chloropropyl)triethoxysilane and bivalent 1,4-diazabicyclo[2.2.2]octane (DABCO) (a strong base). In the second step, a DABCO-S bridge was introduced into dendritic fibrous nanostructured colloidal silica (DFNS) under open-vessel reflux conditions. We refer to the product obtained by incorporating DABCO-S in DFNS as DDS. The unique characteristics of DFNS are completely preserved in this new type of periodic mesoporous organo-silica-DFNS. The produced nanocomposite has a high surface area of about 807 m2 g-1, a large pore volume of 1.9 cm3 g-1, and a bimodal pore size distribution, with small 2.5 nm pores and large 30 nm pores. As such, DDS is an efficient adsorbent for dye removal from wastewater. The results show that DDS can adsorb positive and negative dyes such as methylene blue, orange II sodium salt (OR), and procion red mx-58 (PR) with a capacity of 678, 3192, and 3190 mg dye/g adsorbent. Introducing silver nanoparticles in situ into DDS leads to a composite with excellent accessibility of reactants to the Ag surface, resulting in an efficient catalytic reduction of nitro aromatic compounds (NACs) in aqueous media.

Hybrid Aerogel Nanocomposite of Dendritic Colloidal Silica and Hairy Nanocellulose: an Effective Dye Adsorbent.

In this study, a new type of silica-cellulose hybrid aerogel was synthesized through a green and facile chemical cross-linking process. In a first step, dendritic fibrous nanostructured (colloidal) silica particles (DFNS) were prepared by a simple hydrothermal technique. Then, the surface of DFNS particles was functionalized with amine groups using 3-aminopropyltriethoxysilane to produce DFNS-NH2. In a second step, bifunctional hairy nanocellulose (BHNC) particles were functionalized with both aldehyde and carboxylic groups. The aldehyde groups of BHNC and the amine groups of DFNS-NH2 chemically reacted through a Schiff base reaction to form a hybrid hydrogel nanocomposite. Therefore, no external cross-linker is required in the synthesis. This hybrid aerogel is very lightweight and highly porous with a density of 0.107 g mL-1 and a porosity of 93.0 ± 0.4%. It has a large surface area of 350 m2 g-1, a large pore volume of 0.23 cm3 g-1, and a small pore size of 3.9 nm. The developed aerogel contains both positively and negatively charged functional groups and is a highly efficient substrate for dye adsorption from water, for both cationic and anionic organic dyes. These aerogels were found to have an outstanding adsorption capacity toward methylene blue (MB) as a cationic dye and methyl orange (MO) as an anionic dye. The results show that the aerogels can adsorb MB and MO with a capacity of 270 and 300 mg dye/g adsorbent, respectively.

A green, catalyst-free synthesis of pyrazolopyranopyrimidines in polyethylene glycol as a biodegradable medium at ambient temperature.

A facile, efficient and environmentally safe strategy for the synthesis of pyrazolopyranopyrimidines via one-pot, four-component reaction of hydrazine hydrate, barbituric acid, ethyl acetoacetate, and aromatic aldehydes in polyethylene glycol (PEG) as a safe solvent in the absence of catalyst at ambient temperature has been described. The advantages of the present protocol, such as simplicity, mild conditions, high yields of products, straightforward workup procedure, a green and biodegradable reaction medium, make this new process an attractive to current methodologies.

Synergistic chemo-photothermal therapy using gold nanorods supported on thiol-functionalized mesoporous silica for lung cancer treatment.

Cancer therapy necessitates the development of novel and effective treatment modalities to combat the complexity of this disease. In this project, we propose a synergistic approach by combining chemo-photothermal treatment using gold nanorods (AuNRs) supported on thiol-functionalized mesoporous silica, offering a promising solution for enhanced lung cancer therapy. To begin, mesoporous MCM-41 was synthesized using a surfactant-templated sol-gel method, chosen for its desirable porous structure, excellent biocompatibility, and non-toxic properties. Further, thiol-functionalized MCM-41 was achieved through a simple grafting process, enabling the subsequent synthesis of AuNRs supported on thiol-functionalized MCM-41 (AuNR@S-MCM-41) via a gold-thiol interaction. The nanocomposite was then loaded with the anticancer drug doxorubicin (DOX), resulting in AuNR@S-MCM-41-DOX. Remarkably, the nanocomposite exhibited pH/NIR dual-responsive drug release behaviors, facilitating targeted drug delivery. In addition, it demonstrated exceptional biocompatibility and efficient internalization into A549 lung cancer cells. Notably, the combined photothermal-chemo therapy by AuNR@S-MCM-41-DOX exhibited superior efficacy in killing cancer cells compared to single chemo- or photothermal therapies. This study showcases the potential of the AuNR@S-MCM-41-DOX nanocomposite as a promising candidate for combined chemo-photothermal therapy in lung cancer treatment. The innovative integration of gold nanorods, thiol-functionalized mesoporous silica, and pH/NIR dual-responsive drug release provides a comprehensive and effective therapeutic approach for improved outcomes in lung cancer therapy. Future advancements based on this strategy hold promise for addressing the challenges posed by cancer and transforming patient care.

RSM process optimization of biodiesel production from rapeseed oil and waste corn oil in the presence of green and novel catalyst.

In the scenario of global warming and pollution, the green synthesis and use of biodiesel has acquired utmost priority. Due to several limitations of homogeneous catalysis, organobase immobilized heterogeneous catalyzed production of biodiesel has come out as a favored route. The present report demonstrates the design and synthesis of Peganum harmala spice seed extract modified GO-CuFe2O4 (SSE@GO-CuFe2O4) nanocomposite as an organobase functionalized high surface area magnetic nanocatalyst. Pistachio leaves were used in the green reduction of precursor salts to synthesize CuFe2O4 NPs. The as-synthesized nanomaterial was characterized physicochemically by Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-Ray analysis (EDX), elemental mapping, transmission electron microscopy (TEM), X-Ray diffraction (XRD), thermogravimetric analysis (TGA) and vibrating sample magnetometer techniques (VSM). Subsequently, the catalyst was explored in the efficient synthesis of biodiesels by trans-esterification of two substrates, the rapeseed oil and waste corn oil. The optimum conditions for biodiesel production were determined through response surface methodology based on Box-Behnken design including the study of calibration curves and 3D contour plots. Easy separation and workup, use of green medium, excellent reused for several times and short reaction time are outstanding benefits of this study.

Biotemplated Hollow Mesoporous Silica Particles as Efficient Carriers for Drug Delivery.

We designed three types of hollow-shaped porous silica materials via a three-step biotemplate-directed method: porous hollow silica nanorods, hollow dendritic fibrous nanostructured silica (DFNS), and ultraporous sponge-like DFNS. The first step was making a biotemplate, for which we used cellulose nanocrystals (CNCs), consisting of rod-shaped nanoparticles synthesized by conventional acid hydrolysis of cellulose fibers. In a second step, core-shell samples were prepared using CNC particles as hard template by two procedures. In the first one, core-shell CNC-silica nanoparticles were synthesized by a polycondensation reaction, which exclusively took place at the surface of the CNCs. In the second procedure, a typical synthesis of DFNS was conducted in a bicontinuous microemulsion with the assistance of additives. DFNS was assembled on the surface of the CNCs, giving rise to core-shell CNC-DFNS structures. Finally, all of the silica-coated CNC composites were calcined, during which the CNC was removed from the core and hollow structures were formed. These materials are very lightweight and highly porous. All three structures were tested as nanocarriers for drug delivery and absorbents for dye removal applications. Dye removal results showed that they can adsorb methylene blue efficiently, with ultraporous sponge-like DFNS showing the highest adsorption capacity, followed by hollow DFNS and hollow silica nanorods. Furthermore, breast cancer cells show a lower cell viability when exposed to doxorubicin-loaded hollow silica nanorods compared with control or doxorubicin cultures, suggesting that the loaded nanorod has a greater anticancer effect than free doxorubicin.

Poly(ethylene glycol) grafted onto Dowex resin: an efficient, recyclable, and mild polymer-supported phase transfer catalyst for the regioselective azidolysis of epoxides in water.

In this study, an efficient method was designed to graft poly(ethylene glycol) effectively onto commercial Dowex resin. The catalytic efficiency of the copolymer obtained as a new solid-liquid phase transfer catalyst was studied. It was proved that this organocatalyst is an efficient heterogeneous catalyst for regioselective azidolysis of epoxide in water and gave azidohydrin in excellent yield under mild reaction conditions. The polymeric catalyst was easily recovered by simple filtration and showed no appreciable loss of activity when recycled several times.

ß-Cyclodextrin engineered γ-Fe2O3@ hydroxyapatite nanocomposite as a novel scaffold for the synthesis of phenacyl derivatives.

Magnetic hydroxyapatite (HAp) is being widely investigated for various applications in medical engineering and nanocomposite for transformation reaction. The present work describes an efficient procedure for the synthesis of phenacyl derivatives employing a novel, green and magnetically retrievable nanocomposite via the grafting of ß-cyclodextrin moieties on the magnetic hydroxyapatite surface, γ-Fe2O3@HAp-CD. The structure and composition of the nanocomposite was performed by different methods and analyzed by Infrared Spectroscopy (FT-IR), Field Emission Scanning Electron Microscopy (FE-SEM), transmission electron microscopy (TEM), Thermo-Gravimetric Analysis (TGA), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and Brunauer Emmett Teller (BET) and vibrating sample magnetometry (VSM). Our results indicate that conjugation with ß-CD improves the catalytic activity in the reaction.