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

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1346
Author(s):  
Andreas Breitwieser ◽  
Uwe B. Sleytr ◽  
Dietmar Pum
Keyword(s):  
Carbon Nanotubes ◽  
Covalent Modification ◽  
Silica Layer ◽  
Medical Sciences ◽  
Lysinibacillus Sphaericus ◽  
Wide Range ◽  
Catalytic Sites ◽  
Multi Walled Carbon Nanotubes ◽  
Pristine Mwnts ◽  
Walled Carbon Nanotubes

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.

scholarly journals Fabrication and Characterization of Polylactic Acid Electrospun Scaffolds Modified with Multi-Walled Carbon Nanotubes and Hydroxyapatite Nanoparticles

Biomimetics ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 43
Author(s):  
Athanasios Kotrotsos ◽  
Prokopis Yiallouros ◽  
Vassilis Kostopoulos
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Polylactic Acid ◽  
Physical And Mechanical Properties ◽  
Polymeric Materials ◽  
Cost Effective ◽  
Electrospinning Process ◽  
Wide Range ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

The solution electrospinning process (SEP) is a cost-effective technique in which a wide range of polymeric materials can be electrospun. Electrospun materials can also be easily modified during the solution preparation process (prior SEP). Based on this, the aim of the current work is the fabrication and nanomodification of scaffolds using SEP, and the investigation of their porosity and physical and mechanical properties. In this study, polylactic acid (PLA) was selected for scaffold fabrication, and further modified with multi-walled carbon nanotubes (MWCNTs) and hydroxyapatite (HAP) nanoparticles. After fabrication, porosity calculation and physical and mechanical characterization for all scaffold types were conducted. More precisely, the morphology of the fibers (in terms of fiber diameter), the surface properties (in terms of contact angle) and the mechanical properties under the tensile mode of the fabricated scaffolds have been investigated and further compared against pristine PLA scaffolds (without nanofillers). Finally, the scaffold with the optimal properties was proposed as the candidate material for potential future cell culturing.

scholarly journals Amplitude modulator of Multi-walled Carbon nanotubes/Chitin in the C-band region

2021 ◽  
Vol 2075 (1) ◽  
pp. 012005
Author(s):  
N H Muhamad Apandi ◽  
H Ahmad ◽  
M H Ibrahim ◽  
F Ahmad
Keyword(s):  
Carbon Nanotubes ◽  
Regression Line ◽  
Optical Signal ◽  
Linear Region ◽  
Peak Intensity ◽  
Wide Range ◽  
All Optical ◽  
Multi Walled Carbon Nanotubes ◽  
Amplitude Modulator ◽  
Walled Carbon Nanotubes

Abstract In ultrafast all-optical signal processing, the all-optical method is crucial, and all-fiber technique offers a wide range of applications in optical communications. This study investigated the amplitude modulation using multi-walled carbon nanotubes (MWCNTs) embedded into chitin as saturable absorber (SA). The MWCNTs-chitin SA is fabricate using a liquid phase exfoliation method to reduce complexity and produce an excellent material quality. In this paper, an optical amplitude modulator produced a linear region with a regression line of the peak intensity at pump power range from 17.92 mW to 67.92 mW with modulation efficiency of 0.50 dB/mW.

Dielectrophoretic Assembly of Organized Carbon Nanotubes and Thin Films

2010 ◽  
Author(s):  
Pengfei Li ◽  
Wei Xue
Keyword(s):  
Thin Films ◽  
Carbon Nanotubes ◽  
Nanoelectromechanical Systems ◽  
Experimental Conditions ◽  
Energy Devices ◽  
Nanotube Bundles ◽  
Wide Range ◽  
Multi Walled Carbon Nanotubes ◽  
Controlled Deposition ◽  
Walled Carbon Nanotubes

In this paper, we investigate the dielectrophoretic assembly of organized carbon nanotube (CNT) and CNT thin films. Both single-walled carbon nanotubes (SWNTs) and multi-walled carbon nanotubes (MWNTs) are employed in our experiments. Electrodes with “teeth”-like patterns are fabricated to study the influence of electrode width on CNT deposition and alignment. The entire fabrication process is compatible with optical lithography based techniques. Therefore, the fabrication cost is low and the resulting devices are inexpensive. SWNT and MWNT solutions are prepared with different concentrations. The alignment of SWNT/MWNT thin films and small bundles are achieved under the optimized experimental conditions. The electrical properties of these samples are characterized. The results demonstrate that the controlled deposition of CNT thin films using dielectrophoresis is highly repeatable. The alignment of small nanotube bundles can only be achieved using narrow electrodes and low-concentration solutions. Our investigation shows that it is possible to deposit a controllable amount of CNTs in desirable locations using dielectrophoresis. This research has the potential to enable the development of practical and inexpensive CNT devices that can be used in a wide range of applications: nanoelectronics, nano-bioelectronics, nanoelectromechanical systems (NEMS), and energy devices.

scholarly journals Cytotoxicity Effects of Water-Soluble Multi-Walled Carbon Nanotubes Decorated with Quaternized Hyperbranched Poly(ethyleneimine) Derivatives on Autotrophic and Heterotrophic Gram-Negative Bacteria

2020 ◽  
Vol 13 (10) ◽  
pp. 293
Author(s):  
Nikolaos S. Heliopoulos ◽  
Georgia Kythreoti ◽  
Kyriaki Marina Lyra ◽  
Katerina N. Panagiotaki ◽  
Aggeliki Papavasiliou ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Heterotrophic Bacterium ◽  
Photosynthetic Apparatus ◽  
Covalent Modification ◽  
Water Soluble ◽  
Cyanobacterial Blooms ◽  
Hyperbranched Poly ◽  
Cytotoxicity Studies ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Oxidized multi-walled carbon nanotubes (oxCNTs) were functionalized by a simple non-covalent modification procedure using quaternized hyperbranched poly(ethyleneimine) derivatives (QPEIs), with various quaternization degrees. Structural characterization of these hybrids using a variety of techniques, revealed the successful and homogenous anchoring of QPEIs on the oxCNTs’ surface. Moreover, these hybrids efficiently dispersed in aqueous media, forming dispersions with excellent aqueous stability for over 12 months. Their cytotoxicity effect was investigated on two types of gram(−) bacteria, an autotrophic (cyanobacterium Synechococcus sp. PCC 7942) and a heterotrophic (bacterium Escherichia coli). An enhanced, dose-dependent antibacterial and anti-cyanobacterial activity against both tested organisms was observed, increasing with the quaternization degree. Remarkably, in the photosynthetic bacteria it was shown that the hybrid materials affect their photosynthetic apparatus by selective inhibition of the Photosystem-I electron transport activity. Cytotoxicity studies on a human prostate carcinoma DU145 cell line and 3T3 mouse fibroblasts revealed that all hybrids exhibit high cytocompatibility in the concentration range, in which they also exhibit both high antibacterial and anti-cyanobacterial activity. Thus, QPEI-functionalized oxCNTs can be very attractive candidates as antibacterial and anti-cyanobacterial agents that can be used for potential applications in the disinfection industry, as well as for the control of harmful cyanobacterial blooms.

scholarly journals Investigating of a wide range of concentrations of multi-walled carbon nanotubes on germination and growth of castor seeds (Ricinus communis L.)

2017 ◽  
Vol 57 (3) ◽  
pp. 228-236 ◽  
Author(s):  
Zahra Fathi ◽  
Ramazan-Ali Khavari Nejad ◽  
Homa Mahmoodzadeh ◽  
Taher Nejad Satari
Keyword(s):  
Carbon Nanotubes ◽  
Ricinus Communis ◽  
Germination Rate ◽  
Dry Weight ◽  
Seedling Vigor ◽  
Vigor Index ◽  
Wide Range ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Germination And Growth

Abstract Carbon nanotubes act as regulators of plant germination and growth and are able to change the morphology and physiology of plant cells. The castor plant (Ricinus communis L.) belongs to the Euphorbiaceae family and is a very important medicinal plant. The aim of this study was to investigate the effect of 10 different concentrations of multi-walled carbon nanotubes (MWCNTs) (2, 5, 10, 20, 50, 75, 100, 125, 250 and 500 μg · ml−1) alongside the control under laboratory conditions on the germination and growth of castor seedlings. The results demonstrated that the maximum percentage of germination (96.7%) and relative germination percentage (100%) were found in the concentrations of 50 and 100 μg · ml−1, respectively, and the highest germination rate (53.3%) and the mean germination time (4.6 days) was seen in the concentration of 75 μg · ml−1. However, no statistically significant differences were found between the different concentrations in any of the germination factors. In the concentration of 100 μg · ml−1, there was a significant increase in the seedling vigor index I (400) when compared with the concentrations of 5 and 10 μg · ml−1. The maximum seedling vigor index II (11.3) was found in the concentration of 100 μg · ml−1 and was significantly different from the control and all applied concentrations. The length of radicle in the 100 and 125 μg · ml−1 had a significant increase when compared with the control and the concentrations of 10 and 50 μg · ml−1. The maximum seedling length (4.6 cm) was seen in the concentration of 100 μg · ml−1 where there was a significant increase with 10 μg · ml−1. Moreover, in the 100 μg · ml−1 concentration, the largest number of rootlets (8.6) was seen and when compared with the control and concentrations of 5, 10 and 50 μg · ml−1, there was a statistically significant increase. The maximum wet weight (0.3 g) and dry weight (0.1 g) of seedlings were obtained in the concentration of 100 μg · ml−1 and when compared with the control, there was a significant increase. It was found that in all factors related to the growth of seedlings, the concentrations of 10 and 50 MWCNTs had an inhibitory effect on the response index. The MWCNTs concentration of 100 μg · ml−1 was considered as the optimum concentration in the growth stage of castor seedlings.

Preparation and Characterization of Aluminium Nanocomposites Based on MWCNT

2014 ◽  
Vol 550 ◽  
pp. 30-38
Author(s):  
S. Sivananthan ◽  
S. Gnanasekaran ◽  
Jerold Samuel C. Samson
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Metal Matrix ◽  
High Strength ◽  
Light Weight ◽  
Matrix Composites ◽  
Wide Range ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Metal Matrix Composites (MMC) has wide range of engineering applications such as high strength, temperature, stiffness, yield strength and modulus of rigidity. Among the metals, aluminium is widely used due to its light weight. However, the electrical conductivity of aluminium is low when compared with copper. This paper deals with the development of aluminium nanocomposites based on Multi Walled Carbon Nanotubes (MWCNT) in order to enhance the electrical resistivity of aluminium. Morphology and electrical properties of the nanocomposites has been analyzed and compared with aluminium.

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