Test structures for studying flexible interconnect supported by carbon nanotube scaffolds

Cardiovascular disease is currently the top global cause of death, however, research into new therapies is in decline. Tissue engineering is a solution to this crisis and in combination with the use of carbon nanotubes (CNTs), which have drawn recent attention as a biomaterial, could facilitate the development of more dynamic and complex in vitro models. CNTs’ electrical conductivity and dimensional similarity to cardiac extracellular proteins provide a unique opportunity to deliver scaffolds with stimuli that mimic the native cardiac microenvironment in vitro more effectively. This systematic review aims to evaluate the use and efficacy of CNTs for cardiac tissue scaffolds and was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Three databases were searched: PubMed, Scopus, and Web of Science. Papers resulting from these searches were then subjected to analysis against pre-determined inclusion and quality appraisal criteria. From 249 results, 27 manuscripts met the criteria and were included in this review. Neonatal rat cardiomyocytes were most commonly used in the experiments, with multi-walled CNTs being most common in tissue scaffolds. Immunofluorescence was the experimental technique most frequently used, which was employed for the staining of cardiac-specific proteins relating to contractile and electrophysiological function.

Carbon nanotubes (CNTs) possess exceptional mechanical, thermal, and electrical properties, facilitating their use as reinforcements or additives in various materials to improve the properties of the materials. Furthermore, chemically modified CNTs can introduce novel functionalities. In the medical field, biomaterials are expected to be developed using CNTs for clinical use. Biomaterials often are placed adjacent to bone. The use of CNTs is anticipated in these biomaterials applied to bone mainly to improve their overall mechanical properties, for applications such as high-strength arthroplasty prostheses or fixation plates and screws that will not fail. In addition, CNTs are expected to be used as local drug delivery systems (DDS) and/or scaffolds to promote and guide bone tissue regeneration. However, studies examining the use of CNTs as biomaterials still are in the preliminary stages. In particular, the influence of CNTs on osteoblastic cells or bone tissue is extremely important for the use of CNTs in biomaterials placed in contact with bone, and some studies have explored this. This review paper clarifies the current state of knowledge in the context of the relationship between CNTs and bone to determine whether CNTs might perform in biomaterials in contact with bone, or as a DDS and/or scaffolding for bone regeneration.

Carbon nanotubes (CNT) are highly versatile materials, with an enormous potential for biomedical applications. Their properties are dependent upon production process and may be modified by subsequent chemical treatment. Carbon nanotubes can be used to improve polymers’ composites mechanical properties. Its tailoring allows for the creation of anisotropic nanocomposites (Kanagaraj et al, 2007; Koerner et al, 2004; Pulskamp et al, 2007; Sen et al, 2004). Due to their semi conductive behaviour, its usage may provide electrical stimulation (Grunlan et al, 2004; Huang et al, 2003). The use of CNT as translocators in drug-delivery systems or in image diagnosis has also been suggested (Bianco et al, 2005; Cherukuri et al, 2004). High tumour accumulation of single-walled CNT (SWCNT) has been described, anticipating the possibility of further therapeutic uses (Liu et al, 2007). There are several studies on gas, temperature, pressure, glucose, chemical force and resonator mass sensors based on CNT (Barone et al, 2005; Barone et al, 2005b; Collins et al, 2000; Hrapovic et al, 2004; Kong et al, 2000; Lee et al, 2007; Lin et al, 2005; Perez et al, 2005; Wood et al, 1999; Yan et al, 2007; Yang et al, 2006; Yun et al, 2007). In face of recent studies, special attention has been drawn into promising orthopaedic use of CNT for improving tribological behaviour and material mechanical properties. However, and considering the conductive properties of CNT the range of orthopaedic application may broaden up, since it is known that electrical fields as small as 0,1 mV/cm may enhance osteoblastic proliferation locally (Brighton et al, 1992). CNT based electrodes could be considered for integrating implantable orthopaedic devices. CNT have been reported to have direct and distinct effects on osteoblasts and osteoclasts metabolic functions (Narita et al, 2009; Sirivisoot et al, 2007; Tutak et al, 2009). CNT have been discovered in 1991 (IIjima, 1991), but seem to have been around for quite a long time, since they were detected in gas combustion streams like the ones in normal households stoves (Murr et al, 2004). The fact that CNT are small enough to be inhaled has

Νέα προσέγγιση στην παρακολούθηση της αναπτυσσόμενης βλάβης υπό μηχανική φόρτιση σε ινώδη σύνθετα υλικά με μήτρα ενισχυμένη με νανοσωληνίσκους άνθρακα

Introduction: The need for biocompatible and bioactive scaffolds to accelerate the regeneration and repair of fractured bones has been considered for bone tissue engineering applications during recent decades. The new methods were developed to produce scaffolds to improve the tissue quality, size of cavities, control the porosity and increase the scaffold compressive strength under different loads. The presence of compounds such as hydroxyapatite (HA), which contains calcium and phosphorus ions, is essential for bone marrow transplantation. The use of carbon nanotubes can be considered to improve mechanical, chemical and biological properties, much like bone collagen. However, the construction of bio-nanocomposite scaffold which includes all of the above properties is very important in accelerating bone repair and also in reducing the problems of using other conventional scaffold methods. Materials and Methods: In this paper, the fabrication of a bio-nanocomposite scaffold with a three-dimensional printing method, digital light processing (DLP) has been investigated. The used compounds of photopolymer resin, carbon nanotubes and hydroxyapatite are solvent by ultrasonic and magnet stirrer, then a scaffold model designed in SOLIDWORKS software applied to the DLP 3D printer. Results: The addition of single wall carbon nanotubes (SWCNT) increases the compressive strength of the samples more than two times, beside it leads to an increase in the porosity of the samples due to the addition of SWCNTs. The scaffold porosity was recorded around 75 and 85%, which is associated with a proper compressive strength around 2 -4 MPa. Addition of 2.5 to 5 wt% SWCNT to HA and photopolymer resin can leads to a better mechanical performance compared to the pure sample. Conclusion: The results obtained from this work showed that the above process was successful methodology in preparation of novel scaffold bio-nanocomposites using DLP technique for using in bone tissue engineering.

A critical review of the recent progress on carbon nanotubes-based nanogenerators

Carbon Nanotubes (CNTs) grown on substrates are potential electron sources in field emission applications. Several studies have reported the use of CNTs in field emission devices, including field emission displays, X-ray tube, electron microscopes, cathode-ray lamps, etc. Also, in recent years, conventional cold field emission cathodes have been realized in micro-fabricated arrays for medical X-ray imaging. CNT-based field emission cathode devices have potential applications in a variety of industrial and medical applications, including cancer treatment. Field emission performance of a single isolated CNT is found to be remarkable, but the situation becomes complex when an array of CNTs is used. At the same time, use of arrays of CNTs is practical and economical. Indeed, such arrays on cathode substrates can be grown easily and their collective dynamics can be utilized in a statistical sense such that the average emission intensity is high enough and the collective dynamics lead to longer emission life. The authors in their previous publications had proposed a novel approach to obtain stabilized field emission current from a stacked CNT array of pointed height distribution. A mesoscopic modeling technique was employed, which took into account electro-mechanical forces in the CNTs, as well as transport of conduction electron coupled with electron–phonon induced heat generation from the CNT tips. The reported analysis of pointed arrangements of the array showed that the current density distribution was greatly localized in the middle of the array, the scatter due to electrodynamic force field was minimized, and the temperature transients were much smaller compared to those in an array with random height distribution. In the present paper we develop a method to compute the emission efficiency of the CNT array in terms of the amount of electrons hitting the anode surface using trajectory calculations. Effects of secondary electron emission and parasitic capacitive nonlinearity on the current-voltage signals are accounted. Field emission efficiency of a stacked CNT array with various pointed height distributions are compared to that of arrays with random and uniform height distributions. Effect of this parasitic nonlinearity on the emission switch-on voltage is estimated by model based simulation and Monte Carlo method.

Composites based on the nickel-containing biopolymer complex Ni(20%)-NaPG , possessing catalytic properties in the reaction of hydrogen evolution were obtained and studied. When creating the composite, TUBALL carbon nanotubes were introduced into it to increase reactivity and electrical conductivity. Cyclic voltammetry showed that the use of carbon nanotubes with the Ni(20%)-NaPG complex in catalytic inks provides a decrease in the overpotential of the hydrogen evolution reaction by 65 mV relative to the unmodified glassy carbon electrode. The amplitude of the cathode current at a potential of -1.5 V on the electrode with carbon nanotubes and the Ni(20%)-NaPG complex is 2.34 times higher relative to the unmodified glassy carbon electrode. A comparison was also made of the overpotential of the hydrogen evolution reaction of composites with nanotubes and composites made using VULCAN XC72 carbon black, which is widely used in the creation of electrocatalyst electrodes. The surface morphology of the modified electrodes before and after the introduction of nanotubes was studied using scanning electron microscopy. It was shown that a developed structure was formed on the surface of glassy carbon with a composite containing carbon nanotubes, where nanotubes with an average thickness of 15-20 nm are visible. The elemental composition of the surface of the modified electrodes, obtained using energy-dispersive X-ray spectroscopy, showed the presence of nickel and sodium, which are present in the complex. The results obtained showed a significant increase in the current in the region of hydrogen evolution due to the use of carbon nanotubes as conductive structures in the composite catalytic ink with the biopolymer complex Ni(20%)-NaPG , which confirms the prospects of the chosen research direction.

This review article explores the use of carbon nanotubes (CNTs) as material enhancers in construction and their advantages. It emphasizes ongoing research to gather accurate data on CNT-enhanced material properties and their role in creating more efficient and stronger building materials. The various methods of obtaining and incorporating CNTs into building materials, including chemical vapor deposition and electric arc synthesis, are discussed. A comparative analysis of building materials with and without CNTs is presented to examine their characteristics. The article also discusses future prospects for CNTs in various industries. The study aims to investigate experimental methods for obtaining CNTs, their properties, and their introduction into building materials. The research methodology involves studying literature sources, analyzing experimental results, and examining the structural, mechanical, and electronic properties of CNTs. Analytical methods based on scientific articles and publications related to CNTs in construction were used to ensure the article's reliability, validity, completeness, and objectivity. The research highlights CNTs' potential as material enhancers in construction, owing to their unique mechanical properties, such as high strength, stiffness, and corrosion resistance. Specific studies demonstrating the use of CNTs to increase the strength of concrete and other construction materials are provided, indicating the promising application of CNTs in future construction projects. However, technical challenges must be addressed, and appropriate standards and regulations should be developed before practical implementation.

Carbon nanotubes have a lot of applications in mechanical fields. This is because nanomaterials have many superior mechanical properties such as very high strength-to-weight ratio, high modulus-to-weight ratio, high corrosion resistance, and super intelligence properties, which make them as smart materials. One of these attractive applications is the use of carbon nanotubes in vehicle brake friction material. Therefore, the fabrication and testing processes of these nanomaterials should be performed carefully to evaluate their mechanical, tribological, and noise properties. In this paper, friction material mixed with carbon nanotubes have been fabricated with different carbon nanotube contents and the same fabrication parameters. The carbon nanotubes have been produced using the conventional submerged arc discharge technique. The produced friction materials have been cut into pieces with standard sizes and then tested mechanically and tribologically. The results of tests have illustrated that the addition of carbon nanotubes into the friction materials could improve their mechanical properties (hardness, strength, and modulus) and also could enhance their tribological properties (wear rate and friction coefficient). Moreover, the tests showed that the presence of carbon nanotubes in friction materials could reduce the noise, vibration of the friction materials, and reduce the temperature rise due to the effect of friction, which means that the carbon nanotubes could raise the thermal conductivity of friction material, while the friction coefficient has stayed within the allowable standard limits (0.35–0.45). Surface morphology shows that the presence of carbon nanotubes in the friction materials could help to avoid surface friction cracks or fins within the normal operating conditions. The good combination of mechanical and tribological properties was obtained at 0.5% carbon nanotubes.

This article reviews the impact of carbon nanotubes on analytical science, and the main current and future applications of carbon nanotubes in this field. Given that it is necessary to solubilize carbon nanotubes for many applications, we consider the procedures developed to achieve this. The use of carbon nanotubes in analytical chemistry as a target analyte and as an analytical tool is also discussed. Chromatographic and electrophoretic methods used to separate and characterize carbon nanotubes are presented. The use of carbon nanotubes as an analytical tool in filters and membranes, as sorbent material for solid phase extraction, in electrochemical (bio)sensors, and in separation methods is discussed. It is clear that while nanotubes are being tested for use in many different fields, their truly enormous potential has yet to be realized in analytical chemistry.

Carbon nanotubes (CNTs) hold the promise of delivering exceptional mechanical properties and multifunctional characteristics due to their unique physiochemical properties and prospective applications in various nanotechnologies. However, current techniques of CNTs fabrication cannot produce homogenous CNTs, and this prevents the widespread use of CNTs. Ever-increasing interest in applying CNTs in many different fields has led to continued efforts to develop dispersion and functionalization techniques. Techniques for separating bundles of CNTs into homogeneous dispersion are still under development. The preparation of effective dispersions of CNTs presents a major impediment to the extension and utilization of CNTs. CNTs intrinsically tend to bundle and/or aggregate. The prevention of such behavior has been explored by testing various techniques to improve the dispersibility of CNTs in a variety of solvents. There are mainly two approaches to obtain a good quality dispersion; chemical functionalization and physical interactions. The chemical functionalization technique has been found effective, but deteriorates the intrinsic properties of CNTs through the introduction of defects in the wall. Physical blending approaches with the ultrasound and high speed shearing have been proven capable of debundling CNTs and stabilizing individual CNTs while maintaining their integrity and intrinsic properties. Contemporary methods for dispersion of CNTs in aqueous media are discussed and most attention is paid to molecular dynamics simulation techniques and other physical techniques, as well as to the use of various surfactants and polymers.

While heavy metals (HM) have been considered in recent decades to be the most common and problematic pollutants, the expansion of the list of pollutants due to the active use of carbon nanotubes (CNT) raises new questions about the benefit and harm of HM released to nature individually or fixed on CNT walls. A pot experiment was conducted to compare the effect of two classes of potential pollutants-metal salts of Pb, Mn, Cu, Zn, Cd, and Ni; and functionalized CNTs with COOH, MnO2, Fe3O4, and MnO2-Fe3O4-applied in soil, on the elemental transfer, the bioactive compounds accumulation, and the antioxidant activity in lettuce. While CNTs mainly increased the elemental transfer from soil to leaves, HM salts strongly obstructed it. In the presence of CNTs, the antioxidant activity in lettuce leaves correlated with the transfer of elements from soil to root and from root to leaves. The excess of HMs in soil induced a greater variation of the polyphenols quantity and antioxidant activity than the excess of CNTs. It might be assumed that lettuce perceived HMs as a more aggressive stressor than CNTs and more strongly activated the defense mechanism, showing the reduction of the element transfer and enhancing of total polyphenol production and antioxidant activity.

BackgroundThe intrinsic physicochemical properties of carbon nanotubes (CNTs) make them unique tools in nanotechnology. Their elemental composition, resilience, thermal properties, and surface reactivity make CNTs also of undisputed interest in biotechnology. In particular, their extraordinary ability to capture biomolecules on their surface makes them essential in this field. The proteins adsorbed on the CNTs create a biological coating that endows them the ability to interact with some cell receptors, penetrate membranes or interfere with cell biomechanics, thus behaving as an active bio-camouflage. But some of these proteins unfold, triggering an immune response that unpredictably changes the biological activity of CNTs. For this reason, the control of the biocorona is fundamental in the nanobiotechnology of CNTs.ResultsUsing TEM and AFM here we demonstrate a significant increase in CNTs diameter after protein functionalization. A quantitative analysis using TGA revealed that between 20 and 60% of the mass of functionalized nanotubes corresponds to protein, with single-walled CNTs capturing the highest amounts. To qualitatively/quantitatively characterize these biocoatings, we studied the biochemical "landscape" of the proteins captured by the different nanotubes after functionalization under various conditions. This study revealed a significant variability of the proteins in the corona as a function of the type of nanotube, the functionalization temperature, or the time after exposure to serum. Remarkably, the functionalization of a single type of CNT with sera from various human donors also resulted in different protein landscapes. Given the unpredictable assortment of proteins captured by the corona and the biological implications of this biocoating, we finally designed a method to genetically engineer and produce proteins to functionalize nanotubes in a controlled and customizable way.ConclusionsWe demonstrate the high unpredictability of the spontaneous protein corona on CNTs and propose a versatile functionalization technique that prevents the binding of nonspecific proteins to the nanotube to improve the use of CNTs in biomedical applications.

The clinical application of carbon nanotube (CNT) based solutions has sparked debate within the scientific community, primarily due to concerns about their non-biodegradability, potential long-term toxicity and bioaccumulation in organs and tissues. A significant challenge in evaluating the health risks of CNTs is the lack of standardized guidelines for reliably assessing CNT concentrations in biological systems. Here, we explore the use of time-resolved Raman spectroscopy in association with partial least square (PLS) regression models to detect and quantify CNTs in biological systems. This study included a comprehensive assessment of the structural and chemical characteristics of different types and sources of CNTs. The results revealed that separate PLS models must be developed for each CNT source, as the same CNT type from different suppliers exhibited unique principal components due their varying characteristics. This study highlights the benefits of utilizing the unique Raman signature of CNTs in combination with PLS models to establish a standardized method for detecting and quantifying CNTs, potentially opening precedents for the regulatory frameworks concerning clinical use of CNTs.