Search results for "Mesoporous silica"
showing 10 items of 135 documents
Determination of the chemical warfare agents Sarin, Soman and Tabun in natural waters employing fluorescent hybrid silica materials
2017
[EN] A novel mesoporous silica material containing boron-dipyrromethene (BODIPY) moieties (I) is employed for the detection of nerve agent simulants (NASs) and the organophosphate nerve or chemical warfare agents (CWAs) Sarin (GB), Soman (GD), and Tabun (GA) in aqueous environments. The reactive BODIPY dye with an optimum positioned hydroxyl group undergoes acylation reactions with phosph(on)ate substrates, yielding a bicyclic ring. Due to aggregation of the dyes in water, the sensitivity of the free dye in solution is very low. Only after immobilization of the BODIPY moieties into the silica substrates is aggregation inhibited and a sensitive determination of the NASs diethyl cyanophosphon…
Loading and release of the complex [Pt(DTBTA)(DMSO)Cl]Cl·CHCl3 with the 2,2′-dithiobis(benzothiazole) ligand into mesoporous silica and studies of an…
2018
Abstract Synthetic delivery systems have great potential for overcoming problems associated with systemic toxicity that accompanies chemotherapy with the use of cisplatin and family of platinum anticancer drugs. Mesoporous silicates have been studied in context of drug delivery and drug targeting. In this paper we report the studies of loading and release of a platinum complex, [Pt(DTBTA)(DMSO)Cl]Cl∙CHCl3 (1) where DTBTA = 2,2′-dithiobis(benzothiazole), that was recently synthesized and structurally characterized. Evaluation in vitro of antitumor activity against a human breast cancer cell line (MCF-7) showed a very potent activity of complex(1). Therefore, we thought to incorporate this co…
Target Transportation of Auxin on Mesoporous Au/SiO2 Nanoparticles as a Method for Somaclonal Variation Increasing in Flax (L. usitatissimum L.)
2017
Development of methods for direct delivery of different bioactive substances into the cell is a promising and intensively approached area of research. It has become a subject of serious research for multidisciplinary team of scientists working in such areas as physics, biology, and biotechnology. Plant calluses were grown on medium supplemented with different nanoparticles to be used as a model for biotechnological research. Gold nanoparticles with mesoporous silica coating were used as hormone carriers, since they possess many of critical properties required for cellular transportation instrument. Some of those properties are great biocompatibility and controlled release of carried molecul…
Bimodal porous silica nanomaterials as sorbents for an efficient and inexpensive determination of aflatoxin M1 in milk and dairy products
2020
Abstract An extraction procedure was developed for the determination of aflatoxin M1 in milk and dairy products. A sorbent based on UVM-7 mesoporous silica was used as solid phase for the sample clean-up, and the analyte determination was carried out by HPLC coupled to a fluorescence detector. The material architecture was characterized by transmission electronic microscopy, X-ray diffraction, 29Si NMR and nitrogen adsorption-desorption. After the optimization of extraction parameters, the influence of the matrix has been evaluated, obtaining recoveries in the range 78–105% for whole and skimmed milk and yogurt matrix. The reusability of the material was also proved. The sensitivity of the …
Cyclam-functionalized silica-modified electrodes for selective determination of Cu(II)
2009
Cyclam derivatives have been grafted via 1, 2 or 4 silylated arms to the surface of mesoporous silica and the resulting materials have been incorporated into carbon paste electrodes and applied to the preconcentration electroanalysis of Cu(II). Sensitive and selective detection of the target analyte was achieved owing to the attractive binding properties of this macrocyclic ligand towards Cu(II) species. Various parameters likely to affect the preconcentration and detection steps have been studied, including pH of the accumulation medium, composition of the detection solution, structure and composition of the adsorbent, accumulation time, or presence of potentially interfering species. In p…
Comparison of silica-based materials for organophosphorus pesticides sampling and occupational risk assessment.
2020
Abstract A novel air sampler has been designed containing a sorbent based on UVM-7 mesoporous silica doped with Ti. The sorbent has been applied for the determination of organophosphorus pesticides in occupational air, followed by gas chromatography with mass spectrometry detection. Thus, several silica materials with different structures (mesoporous UVM-7 and microporous xerogels) were synthesized, and modified with the addition of Ti and Fe. The structure of these materials was proved by transmission electronic microscopy, energy-dispersive X-ray, X-ray diffraction, nitrogen adsorption-desorption and UV–Vis and Raman spectroscopy. The potential of these materials for the retention of pest…
Understanding the role of Ti-rich domains in the stabilization of gold nanoparticles on mesoporous silica-based catalysts
2018
3 Tablae, 14 Figures.-- Supplementary material.-- © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
Borate-driven gatelike scaffolding using mesoporous materials functionalised with saccharides.
2009
We report the development of an MCM-41 mesoporous support that is functionalised with saccharides at the pore outlets and contains the dye [Ru(bipy)(3)](2+) in the pores (solid S1; bipy = 2,2'-bipyridyl). For this hybrid system, the inhibition of mass transport of the dye from the pore voids to the bulk solution in the presence of borate is demonstrated in water at neutral pH. The formation of the corresponding boroester derivative is related to the selective reaction of borate with the appended saccharides. This control is selective and only anion borate, among several anions and cations, can act as a molecular tap and inhibit the delivery of the entrapped guest. Additionally, the S1-borat…
Development of controlled release systems of biocides for the conservation of cultural heritage
2017
Abstract The presence of microorganisms is one of the main causes of monument deterioration. Biocides are usually applied after or before restoration in order to prevent or slow down microbial growth. Frequent applications are necessary leading to increased costs and high risks to humans and the environment. The aim of this study is the design of novel controlled release systems comprising a biocide loaded into a mesoporous silica. Pristine MCM41 as well as MCM41 functionalised with carboxy- (MCM41-COOH) and amino-groups (MCM41-NH2) were used. Biotin T and New Des 50, two commercial formulations, were chosen as biocides. The biocide encapsulation was performed adding the mesoporous silica t…
Formulation of Mesoporous Silica Nanoparticles for Controlled Release of Antimicrobials for Stone Preventive Conservation
2020
The biotic deterioration of artifacts of archaeological and artistic interest mostly relies on the action of microorganisms capable of thriving under the most disparate environmental conditions. Thus, to attenuate biodeterioration phenomena, biocides can be used by the restorers to prevent or slow down the microbial growth. However, several factors such as biocide half-life, its wash-out because of environmental conditions, and its limited time of action make necessary its application repeatedly, leading to negative economic implications. Sound and successful treatments are represented by controlled release systems (CRSs) based on porous materials. Here, we report on the design and developm…