Biomimetic chitosan-mediated synthesis in heterogeneous phase of bulk and mesoporous silica nanoparticles

Both bulk and mesoporous silica nanoparticles can be obtained in the form of granular aggregates using chitosan flakes as additive under very soft biomimetic reaction conditions.Puchol Estors, Victoria, [email protected] ; El Haskouri, Jamal, [email protected] ; Latorre Saborit, Julio, [email protected] ; Beltran Porter, Aurelio, [email protected] ; Beltran Porter, Daniel, [email protected] ; Amoros del Toro, Pedro Jose, [email protected]

Use of Silica Based Materials as Modulators of the Lipase Catalyzed Hydrolysis of Fats under Simulated Duodenal Conditions

The effect of silica materials and their functionalization in the lipase catalyzed fat hydrolysis has been scarcely studied. Fifteen silica materials were prepared and their effect on the fat hydrolysis was measured, under simulated duodenal conditions, using the pH-stat method. The materials are composed of the combination of three supports (Stöber massive silica nanoparticles, Stöber mesoporous nanoparticles and UVM-7) and four surface functionalizations (methyl, trimethyl, propyl and octyl). In addition, the non-functionalized materials were tested. The functional groups were selected to offer a hydrophobic character to the material improving the interaction with the fat globules and the lipase. The materials are able to modulate the lipase activity and their effect depending on the support topology and the organic covering, being able to increase or reduce the fat hydrolysis. Depending of the material, relative fat hydrolysis rates of 75 to 140% in comparison with absence of the material were obtained. The results were analyzed by Partial Least Square Regression and suggest that the alkyl modified mesopores are able to improve the fat hydrolysis, by contrast the non-porous nanoparticles and the textural pores tend to induce inhibition. The effects are more pronounced for materials containing long alkyl chains and/or in absence of taurodeoxycholate

Very high titanium content mesoporous silicas

Titanium content in mesoporous titanosilicate catalysts has been modulated up to a minimum Si/Ti value of 1.9 by using complexing agents able to coordinate both Si and Ti atoms and harmonize the reactivity of the resulting precursors avoiding subsequent phase segregation and leading to chemically very homogeneous materials.El Haskouri, Jamal, [email protected] ; Beltran Porter, Aurelio, [email protected] ; Beltran Porter, Daniel, [email protected] ; Amoros del Toro, Pedro Jose, [email protected]

Supramolecular self-assembling in mesostructured materials through charge tuning in the inorganic phase

Supramolecular self-assembling of organic CTA+ micelles and inorganic [VO(H2O)PO4]n^q-2 2D-anions for the isolation of hexagonal mesostructured materials can be reached by charge tuning in the inorganic phase through the adjustment of the vanadium mean oxidation state.El Haskouri, Jamal, [email protected] ; Cabrera Medina, Saul, [email protected] ; Beltran Porter, Aurelio, [email protected] ; Alamo Serrano, Jaime, [email protected] ; Beltran Porter, Daniel, [email protected] ; Amoros del Toro, Pedro Jose, [email protected]

A new method for fluoride determination by using fluorophores and dyes anchored onto MCM-41

A new colourimetric and fluorimetric method for fluoride determination in aqueous samples based on the specific reaction between fluoride and silica has been developed and applied on real samples.Descalzo Lopez, Ana Belen, [email protected] ; El Haskouri, Jamal, [email protected] ; Beltran Porter, Daniel, [email protected] ; Amoros del Toro, Pedro Jose, [email protected]

Tuning the pore size from micro- to meso-porous in thermally stable aluminophosphates

Thermally stable porous aluminophosphates (ICMUV-3) with P/Al molar ratios in the range 0.15 <= P/Al <= 0.75 and showing continuously adjustable pore sizes from 13 to 37 Å have been prepared through a surfactant-assisted procedure without changing the surfactant length and/or addition of organic expansors.Cabrera Medina, Saul, [email protected] ; El Haskouri, Jamal, [email protected] ; Beltran Porter, Aurelio, [email protected] ; Beltran Porter, Daniel, [email protected] ; Amoros del Toro, Pedro Jose, [email protected]

Highly active hydrogenation catalysts based on Pd nanoparticles dispersed along hierarchical porous silica covered with polydopamine as interfacial glue

New catalysts based on Pd(0) nanoparticles (Pd NPs) on a bimodal porous silica of the UVM-7/polydopamine (PDA) support have been synthesized following two preparative strategies based on the sequential or joint incorporation of two components of the composite (Pd and PDA). We analyzed the role played by the PDA as 'interfacial glue' between the silica scaffold and the Pd NPs. The catalysts were tested for the hydrogenation of 4-nitrophenol using (NEt4)BH4 as the hydrogenating agent. In addition to the palladium content, the characterization of the catalysts at the micro and nanoscale has highlighted the importance of different parameters, such as the size and dispersion of the Pd NPs, as well as their accessibility to the substrate (greater or lesser depending on their entrapment level in the PDA) on the catalytic efficiency. Staged sequential synthesis has led to better catalytic results. The most active Pd(0) centers seem to be Pd NPs of less than 1 nm on the PDA surface. The efficiency of the catalysts obtained is superior to that of similar materials without PDA. A comprehensive comparison has been made with other catalysts based on Pd NPs in a wide variety of supports. The TOF values achieved are among the best described in the literature

Chromogenic Chemodosimeter Based on Capped Silica Particles to Detect Spermine and Spermidine

[EN] A new hybrid organic-inorganic material for sensing spermine (Spm) and spermidine (Spd) has been prepared and characterized. The material is based on MCM-41 particles functionalized with an N-hydroxysuccinimide derivative and loaded with Rhodamine 6G. The cargo is kept inside the porous material due to the formation of a double layer of organic matter. The inner layer is covalently bound to the silica particles, while the external layer is formed through hydrogen and hydrophobic interactions. The limits of detection determined by fluorimetric titration are 27 mu M and 45 mu M for Spm and Spd, respectively. The sensor remains silent in the presence of other biologically important amines and is able to detect Spm and Spd in both aqueous solution and cells.This research was funded by Spanish Government (RTI2018-100910-B-C42 and RTI2018100910-B-C44 (MCUI/AEI/FEDER, UE) and grant GRISOLIAP/2019/023.Barros, M.; López-Carrasco, A.; Amorós, P.; Gil Grau, S.; Gaviña, P.; Parra Alvarez, M.; El Haskouri, J.... (2021). Chromogenic Chemodosimeter Based on Capped Silica Particles to Detect Spermine and Spermidine. Nanomaterials. 11(3):1-12. https://doi.org/10.3390/nano1103081811211

Towards the Loewenstein limit (Si/Al = 1) in thermally stable mesoporous aluminosilicates

The use of complexing agents to generate polynuclear precursor species containing both Al and Si allows the synthesis of thermally stable mesoporous aluminosilicates including solely tetrahedrally coordinated aluminium, in which the Si/Al ratio can be modulated down to a minimum Si/Al value of 1.06(4).Cabrera Medina, Saul, [email protected] ; El Haskouri, Jamal, [email protected] ; Latorre Saborit, Julio, [email protected] ; Beltran Porter, Aurelio, [email protected] ; Beltran Porter, Daniel, [email protected] ; Amoros del Toro, Pedro Jose, [email protected]