Enzymes and Other Proteins Entrapped in Sol-Gel Materials

Avnir, David; Braun, Sergei; Lev, Ovadia; Ottolenghi, Michael

doi:10.1021/cm00046a008

Cited by 836 publications

(518 citation statements)

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“…We do so by using the sol-gel materials methodology for enzyme entrapment [1]. Sol-gel entrapped enzymes [2][3][4] have already been shown to provide significant thermal stability [5][6][7][8], stability to extreme pH values [9][10][11], and stability to non-native environments [12][13][14]. In these earlier studies the protectability was attributed to the encaging itself [15]; here we extend these observations by showing protection against an oxidant due to active chemical scavenging of the destructive chemical by the matrix.…”

Section: Introductionsupporting

confidence: 64%

Erratum to: Preserving the activity of enzymes under harsh oxidizing conditions: sol–gel entrapped alkaline phosphatase exposed to bromine

Frenkel-Mullerad

Ben-Knaz

Avnir

2014

J Sol-Gel Sci Technol

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Chemically reactive sol-gel matrices hold the ability of protecting entrapped enzymes from destruction by external harsh chemicals. We show this concept by exposing alkaline phosphatase (AlP) to a strong oxidizing agent-bromine. In solution, AlP is immediately destroyed by this oxidant. When AlP was entrapped in hybrid silica sol-gel materials carrying double bonds, the reactivity of AlP was preserved after exposure to bromine under conditions which totally destroy it in solution. The matrices studied were vinylated and allylated silicas, and their protectability was compared to n-alkylated silicas and to silica itself. For instance, the reactivity of AlP entrapped in allylated silica after exposure to 25.6 mM bromine solution is 40 times higher than its reactivity when entrapped in pure silica; and in solution the enzyme is totally destroyed at this concentration. Molecular level mechanisms for these observations are proposed.Keywords Sol-gel Á Sol-gel preserved enzymes Á Oxidizing agent Á Ormosil BackgroundAlkaline phosphatase (AlP), like most other enzymes, is totally destructed when exposed to a strong oxidant such as bromine. Here we show how to protect an enzyme when exposed to such conditions. We do so by using the sol-gel materials methodology for enzyme entrapment [1]. Sol-gel entrapped enzymes [2-4] have already been shown to provide significant thermal stability [5][6][7][8], stability to extreme pH values [9][10][11], and stability to non-native environments [12][13][14]. In these earlier studies the protectability was attributed to the encaging itself [15]; here we extend these observations by showing protection against an oxidant due to active chemical scavenging of the destructive chemical by the matrix. Thus when the enzyme is entrapped within sol-gel derived olefinated silicas, and then exposed to bromine solution, the double bonds react with the bromine, and protect the enzyme. By comparing this mode of protection to entrapments in non-reactive matrices-sol-gel derived silicas and sol-gel-derived alkylated silicas-we were able to evaluate the weights of the bromine scavenging and of the physical entrapment to the protection of the enzyme; we find that this relative weight depends on the alkyl and alkenyl chain. Thus, the hybrid sol-gel material we used was based on vinyl (CH 2 =CH-Si; VTS; here and below we use the name of the monomer as the name of the material), or allyl (CH 2 =CH-CH 2 -Si; ATS). In earlier studies we showed these olefinated sol-gel materials are highly reactive towards bromine, undergoing in water an hydrobromination reaction [16,17] which proceeds according to Markovnikov's rule [18], as shown in Scheme 1, resulting in a bromohydrin and HBr. The formation of an acid is an environmental change that the entrapped enzyme can withstand. We recall that we showed that sol-gel entrapped alkaline phosphataseThe online version of the original article can be found under

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Section: Introductionsupporting

confidence: 64%

Erratum to: Preserving the activity of enzymes under harsh oxidizing conditions: sol–gel entrapped alkaline phosphatase exposed to bromine

Frenkel-Mullerad

Ben-Knaz

Avnir

2014

J Sol-Gel Sci Technol

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“…Sol-gel synthesis of inorganic gels in conditions as harmless as possible is such an option. Silica sol-gel materials have been developed starting with the 1990's as a versatile and viable alternative to classical immobilization methods (Avnir et al, 1994;Reetz et al, 2000, Reetz et al, 2003. The sol-gel synthesis of silica gels is a chemical synthesis of amorphous inorganic solids starting from metal-organic precursors (Si(OCH 3 ) 4 or Si(OC 2 H 5 ) 4 being the most commonly used) which undergo numerous catalytic hydrolysis and condensation reactions that can be written schematically as follow (Brinker & Scherer, 1990;Park & Clark, 2002 …”

Section: Sol-gel Entrapment -A Versatile Tool For Enzyme Immobilizationmentioning

confidence: 99%

“…entrapment in silica gels by sol-gel route is now history (Avnir et al, 1994;Gill & Ballesteros, 2000;Livage et al, 2001;Retz et al, 2000). Application of sol-gel technique in biosensing has been a logical consequence (Kunzelmann & Bottcher., 1997;de Marcos et al, 1999;Wang, 1999).…”

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confidence: 99%

Sol-gel technology in enzymatic electrochemical biosensors for clinical analysis

Preda¹,

Bizerea²,

Vlad-Oros³

2011

Biosensors for Health, Environment and Biosecurity

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“…However, due to the crowded environment of the living cell, excluded volume effects play a significant role in the function, stability, and interactions of individual macromolecules. To create a crowded microenvironment, many researchers have started to encapsulate model proteins in silica glass using a sol-gel technique [57]. This sol-gel glass encapsulation is performed at room temperature, and the chemical conditions during processing do not denature most biomolecules, which makes this an attractive method of immobilizing the enzyme.…”

Section: Protein Folding In Confinementmentioning

confidence: 99%

Chemistry in nanochannel confinement

Gardeniers

2009

Anal Bioanal Chem

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This review addresses the questions of whether it makes sense to use lithographically defined nanochannels for chemistry in liquids, and what it is possible to learn from experiments on that topic. The behavior of liquids in different classes of pores (categorized according to their size) is reviewed, with a focus on chemical reactions and protein dynamics. A number of interesting phenomena are discussed for nanochannels with feature sizes that are manufacturable with modern photolithography-based fabrication technology. The use of spectroscopic methods to investigate chemistry in nanochannels, where both spectroscopic method and nanochannels are integrated into a single device, will be evaluated.

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Enzymes and Other Proteins Entrapped in Sol-Gel Materials

Cited by 836 publications

References 4 publications

Erratum to: Preserving the activity of enzymes under harsh oxidizing conditions: sol–gel entrapped alkaline phosphatase exposed to bromine

Erratum to: Preserving the activity of enzymes under harsh oxidizing conditions: sol–gel entrapped alkaline phosphatase exposed to bromine

Sol-gel technology in enzymatic electrochemical biosensors for clinical analysis

Chemistry in nanochannel confinement

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