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A New Method for Dispersing Pristine Carbon Nanotubes Using Regularly Arranged S-Layer Proteins

Homogeneous and stable dispersions of functionalized carbon nanotubes (CNTs) in aqueous solutions are imperative for a wide range of applications, especially in life and medical sciences. Various covalent and non-covalent approaches were published to separate the bundles into individual tubes. In th...

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Autores principales: Breitwieser, Andreas, Sleytr, Uwe B., Pum, Dietmar
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8161383/
https://www.ncbi.nlm.nih.gov/pubmed/34065322
http://dx.doi.org/10.3390/nano11051346
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author Breitwieser, Andreas
Sleytr, Uwe B.
Pum, Dietmar
author_facet Breitwieser, Andreas
Sleytr, Uwe B.
Pum, Dietmar
author_sort Breitwieser, Andreas
collection PubMed
description Homogeneous and stable dispersions of functionalized carbon nanotubes (CNTs) in aqueous solutions are imperative for a wide range of applications, especially in life and medical sciences. Various covalent and non-covalent approaches were published to separate the bundles into individual tubes. In this context, this work demonstrates the non-covalent modification and dispersion of pristine multi-walled carbon nanotubes (MWNTs) using two S-layer proteins, namely, SbpA from Lysinibacillus sphaericus CCM2177 and SbsB from Geobacillus stearothermophilus PV72/p2. Both the S-layer proteins coated the MWNTs completely. Furthermore, it was shown that SbpA can form caps at the ends of MWNTs. Reassembly experiments involving a mixture of both S-layer proteins in the same solution showed that the MWNTs were primarily coated with SbsB, whereas SbpA formed self-assembled layers. The dispersibility of the pristine nanotubes coated with SbpA was determined by zeta potential measurements (−24.4 +/− 0.6 mV, pH = 7). Finally, the SbpA-coated MWNTs were silicified with tetramethoxysilane (TMOS) using a mild biogenic approach. As expected, the thickness of the silica layer could be controlled by the reaction time and was 6.3 +/− 1.25 nm after 5 min and 25.0 +/− 5.9 nm after 15 min. Since S-layer proteins have already demonstrated their capability to bind (bio)molecules in dense packing or to act as catalytic sites in biomineralization processes, the successful coating of pristine MWNTs has great potential in the development of new materials, such as biosensor architectures.
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spelling pubmed-81613832021-05-29 A New Method for Dispersing Pristine Carbon Nanotubes Using Regularly Arranged S-Layer Proteins Breitwieser, Andreas Sleytr, Uwe B. Pum, Dietmar Nanomaterials (Basel) Article Homogeneous and stable dispersions of functionalized carbon nanotubes (CNTs) in aqueous solutions are imperative for a wide range of applications, especially in life and medical sciences. Various covalent and non-covalent approaches were published to separate the bundles into individual tubes. In this context, this work demonstrates the non-covalent modification and dispersion of pristine multi-walled carbon nanotubes (MWNTs) using two S-layer proteins, namely, SbpA from Lysinibacillus sphaericus CCM2177 and SbsB from Geobacillus stearothermophilus PV72/p2. Both the S-layer proteins coated the MWNTs completely. Furthermore, it was shown that SbpA can form caps at the ends of MWNTs. Reassembly experiments involving a mixture of both S-layer proteins in the same solution showed that the MWNTs were primarily coated with SbsB, whereas SbpA formed self-assembled layers. The dispersibility of the pristine nanotubes coated with SbpA was determined by zeta potential measurements (−24.4 +/− 0.6 mV, pH = 7). Finally, the SbpA-coated MWNTs were silicified with tetramethoxysilane (TMOS) using a mild biogenic approach. As expected, the thickness of the silica layer could be controlled by the reaction time and was 6.3 +/− 1.25 nm after 5 min and 25.0 +/− 5.9 nm after 15 min. Since S-layer proteins have already demonstrated their capability to bind (bio)molecules in dense packing or to act as catalytic sites in biomineralization processes, the successful coating of pristine MWNTs has great potential in the development of new materials, such as biosensor architectures. MDPI 2021-05-20 /pmc/articles/PMC8161383/ /pubmed/34065322 http://dx.doi.org/10.3390/nano11051346 Text en © 2021 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Breitwieser, Andreas
Sleytr, Uwe B.
Pum, Dietmar
A New Method for Dispersing Pristine Carbon Nanotubes Using Regularly Arranged S-Layer Proteins
title A New Method for Dispersing Pristine Carbon Nanotubes Using Regularly Arranged S-Layer Proteins
title_full A New Method for Dispersing Pristine Carbon Nanotubes Using Regularly Arranged S-Layer Proteins
title_fullStr A New Method for Dispersing Pristine Carbon Nanotubes Using Regularly Arranged S-Layer Proteins
title_full_unstemmed A New Method for Dispersing Pristine Carbon Nanotubes Using Regularly Arranged S-Layer Proteins
title_short A New Method for Dispersing Pristine Carbon Nanotubes Using Regularly Arranged S-Layer Proteins
title_sort new method for dispersing pristine carbon nanotubes using regularly arranged s-layer proteins
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8161383/
https://www.ncbi.nlm.nih.gov/pubmed/34065322
http://dx.doi.org/10.3390/nano11051346
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