Packed hybrid silica nanoparticles as sorbents with thermo-switchable surface chemistry and pore size for fast extraction of environmental pollutants

Jadhav, Sushilkumar A.; Nisticò, Roberto; Magnacca, Giuliana; Scalarone, Dominique Maria

doi:10.1039/c7ra11869d

Cited by 28 publications

(11 citation statements)

References 39 publications

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“…Figure A shows the ATR-FTIR spectra of the native and immobilized enzyme. The silica particles display a broad peak at 1070 cm –1 , resulting from asymmetric vibrations of Si–O . The enzyme immobilization results in new peaks, particularly the amide I band (1600–1700 cm –1 ) related to C–O stretching vibrations and the amide II band (1510–1580 cm –1 ) related to N–H bending. , New peaks between 3000 and 3700 cm –1 are indicative of N–H stretching and side-chain stretching. , In addition, zeta potential measurements reveal surface charge inversion, confirming the successful deposition of layers (Figure B).…”

Section: Results and Discussionmentioning

confidence: 81%

“…The silica particles display a broad peak at 1070 cm −1 , resulting from asymmetric vibrations of Si−O. 50 The enzyme immobilization results in new peaks, particularly the amide I band (1600−1700 cm −1 ) related to C−O stretching vibrations and the amide II band (1510−1580 cm −1 ) related to N−H bending. 51,52 New peaks between 3000 and 3700 cm −1 are indicative of N−H stretching and sidechain stretching.…”

Section: ■ Introductionmentioning

confidence: 99%

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Improving β-Galactosidase-Catalyzed Transglycosylation Yields by Cross-Linked Layer-by-Layer Enzyme Immobilization

Alavijeh

Meyer

Gras

et al. 2020

ACS Sustainable Chem. Eng.

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The biotransformation of lactose into gut-bioactive glycans catalyzed by βgalactosidase can give economic value to lactose-rich side streams generated in the food or dairy industry. Herein, we study the immobilization of the commercially used β-galactosidase from Bacillus circulans onto silica particles using an enzyme immobilization technology involving a cross-linked layer-by-layer encapsulation method. The immobilized β-galactosidase was used for the synthesis of Nacetyllactosamine (LacNAc) as an important precursor for numerous bioactive compounds and a prebiotic in itself. Techniques including molecular analysis, enzyme activity determination, secondary structure analysis, thermodynamic characterization as well as the determination of thermal and operational stability were conducted to characterize the immobilized enzyme. Changes in the activity of the enzyme after immobilization were attributed to possible changes in electrostatic, covalent and protein-protein interactions. Immobilization significantly improved enzymatic LacNAc yield compared to the free enzyme. In turn, this improved the economics and the sustainability of the process. The immobilized enzyme encapsulated in multilayer films was significantly more stable in the presence of divalent cations and its thermostability also substantially increased, with the thermal denaturation activation energy increasing from 53 kJ mol -1 to 294 kJ mol -1 . The immobilized enzyme was successfully reused in eight consecutive reaction cycles with no significant reduction in the LacNAc yield. The improved transgalactosylation yield and productivity, higher stability and reusability obtained with this immobilization method provide new opportunities for industrial applications.

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Section: Results and Discussionmentioning

confidence: 81%

Section: ■ Introductionmentioning

confidence: 99%

Improving β-Galactosidase-Catalyzed Transglycosylation Yields by Cross-Linked Layer-by-Layer Enzyme Immobilization

Alavijeh

Meyer

Gras

et al. 2020

ACS Sustainable Chem. Eng.

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“…Upon heating above the lower critical solution temperature (LCST), the PNIPAM chains grafted on the particles undergo a typical reversible transition from water soluble hydrophilic coils to water insoluble hydrophobic globules [16][17][18]. This transition of the polymer transforms the silica surface into a surface with switchable properties, which is hydrophilic at normal (or room) temperatures and hydrophobic at elevated temperatures [19]. In addition, thermoresponsive polymers grafted on the surface of silica particles modify their packing behaviour and improve their stability [19].…”

Section: Introductionmentioning

confidence: 99%

“…This transition of the polymer transforms the silica surface into a surface with switchable properties, which is hydrophilic at normal (or room) temperatures and hydrophobic at elevated temperatures [19]. In addition, thermoresponsive polymers grafted on the surface of silica particles modify their packing behaviour and improve their stability [19]. In packed particle beds porosity is formed by the inter-particle voids.…”

Section: Introductionmentioning

confidence: 99%

Thermally triggered on demand permeability of hybrid silica beds made of packed thermoresponsive organo-silica microparticles

Jadhav¹,

Spalletta²,

Scalarone³

2019

Express Polym. Lett.

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This work reports the preparation and testing of porous beds made from packed vinylated silica microparticles (SiMPs) grafted with thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) and exhibiting on demand thermally triggered permeability. PNIPAM-grafted hybrid SiMPs with diameters of 1.40-1.55 µm were synthesized and characterized with Attenuated Total Reflection Fourier Transform Infrared Spetroscopy (ATR-FTIR), Thermogravimetric Analysis (TGA), Flow Particle Image Analysis (FPIA) and Scannning Electron Miscroscopy (SEM) to elucidate their composition and morphology. The PNIPAM-grafted SiMPs were used to prepare thermoresponsive beds of dimensions 1×0.5×0.5 cm inside filtration tubes. The thermo-regulated permeability of solutions of selected model compounds, namely caffeine, ketoprofen, orange II, bromocresol green and cresol red across the hybrid beds was tested by calculating the retention percentage of the model compounds at temperatures below and above the lower critical solution temperature (LCST) of PNIPAM. The results showed a clear control over the permeability of the packed hybrid beds mediated by external temperature changes. This control was achieved by virtue of the switchable nanovalves created by the thermoresponsive PNIPAM present in the inter-particle voids of the packed beds.

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“…In this context, surface coating with a layer of sol-gel silica to construct core-shell structures has been used as a general method to improve the stability of the inner nanoparticles. [21][22][23][24][25][26][27][28] For example, Tong et al reported the use of poly(1-vinylimidazole)-graed Fe 3 O 4 @SiO 2 particles with improved stability as reusable adsorbents for the removal of Hg 2+ in waste water. 25 The protective ability of silica shells depends on their permeability to species that attack the inner nanoparticles.…”

Section: Introductionmentioning

confidence: 99%

Anomalous effect of the aging degree on the ionic permeability of silica shells

Wang

Chen

et al. 2018

RSC Adv.

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Packed hybrid silica nanoparticles as sorbents with thermo-switchable surface chemistry and pore size for fast extraction of environmental pollutants

Abstract: Thermoresponsive poly(N-isopropylacrylamide)-grafted silica nanoparticles were synthesized and used to prepare solid phase extraction sorbents with switchable pore size and surface chemistry for temperature-regulated extraction of water pollutants.

Cited by 28 publications

References 39 publications

Improving β-Galactosidase-Catalyzed Transglycosylation Yields by Cross-Linked Layer-by-Layer Enzyme Immobilization

Improving β-Galactosidase-Catalyzed Transglycosylation Yields by Cross-Linked Layer-by-Layer Enzyme Immobilization

Thermally triggered on demand permeability of hybrid silica beds made of packed thermoresponsive organo-silica microparticles

Anomalous effect of the aging degree on the ionic permeability of silica shells

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