Sulforaphane is a naturally occurring active substance found in vegetables that is known for its potential in preventing and treating cancer. This compound has demonstrated promising effects in inhibiting the growth of various types of cancer, including esophageal, lung, colon, breast, and liver cancer. However, its instability towards pH and heat limits its application in the medical and food industries. To address this challenge, novel drug delivery systems have been developed to improve the stability and efficacy of sulforaphane, making it a more suitable candidate for clinical use in cancer research. In this study, nanocomposite materials were prepared using multi-walled carbon nanotubes (MWCNTs) and chitosan (CS) as base materials, with polydopamine (PDA) acting as a bridge material. The synthesized composite materials were used as drug carriers for the release of sulforaphane. The results of the study showed that the drug loading increased with an increase in the concentration of sulforaphane, indicating that the nanocomposite materials were effective in delivering and releasing the drug. Moreover, a positive correlation was observed between the drug loading and the thickness of the PDA layer. These findings suggest that the use of MWCNTs, CS, and PDA in the development of drug delivery systems can enhance the stability and efficacy of sulforaphane, potentially leading to improved cancer treatment outcomes.

A glassy carbon electrode modified with a composite consisting of electrodeposited chitosan and carboxylated multi-walled carbon nanotubes (e-CS/MWCNTs/GCE) was used as a working electrode for simultaneous determination of dopamine (DA), serotonin (5-HT) and melatonin (MT), which were related to circadian rhythms. The electrochemical characterizations of the working electrode were carried out via electrochemical impedance spectroscopy and chronocoulometry. It was found that electrochemical modification method, that was cyclic voltammetry, may can cause continuous CS polymerization on MWCNTs surface to form a dense membrane with more active sites on the electrode, and the electrochemically active surface area of e-CS/MWCNTs/GCE obtained was about 7 times that of GCE. The electrochemical behaviour of DA, 5-HT and MT on working electrode were carried out via differential pulse voltammetry and cyclic voltammetry. The results showed that e-CS/MWCNTs/GCE solved the problem that the bare electrode could not detect three substances simultaneously, and can catalyze oxidation potential difference as low as 0.17 V of two substances reaction at the same time, indicating very good electrocatalytic activity. By optimizing the detection conditions, the sensor showed a good linear response to DA, 5-HT and MT in the range of 20-1000 μmol/L, 9-1000 μmol/L and 20-1000 μmol/L, and the detection limits were 12 μmol/L, 10 μmol/L and 22 μmol/L (S/N = 3), respectively. In addition, the proposed sensor was successfully applied to the simultaneous detection of DA, 5-HT and MT in human saliva samples.

In this study, gold nanoparticles (AuNPs) were synthesised using green chemistry to decorate multi-walled carbon nanotubes (MWCNTs) made from walnut shells transmission electron microscopy, field-emission scanning electron microscopy (FESEM), atomic force microscopy and fourier transforms infrared spectroscopy were used to diagnose MWCNTs and AuNPs. MWCNT-COOAu, MWCNT-COO and MWCNT-Au were diagnosed by Raman, energy dispersive X-ray analysis and FESEM. The effect of AuNPs, MWCNT-COO, MWCNT-COOAu and MWCNT-Au on pure and serum alkaline phosphatase (ALP) enzyme activity was studied in vitro using the enzyme-substrate 4-nitrophenyl disodium orthophosphate. For pure enzymes, Vmax slightly increased as the concentration of MWCNT-Au, MWCNT-COOAu and MWCNTCOO increased, whereas the Vmax values decreased as the concentration of AuNPs increased. The inhibition type for all NPs varied. For serum ALP enzyme, the Vmax values for Au-based NPs decreased as the concentration of NPs increased. The Vmax values exceeded the standard value at the concentrations of 25, 50 and 75 ppm for MWCNT-Au and MWCNT-COOAu, whereas the Vmax values increased over the standard value for all concentrations of AuNPs.

Single-walled carbon nanotube (SWNT) has gained significant interest as a transducer in various electrochemical sensing devices due to their unique structure, compatibility with biomolecules, and excellent electronic properties. As-prepared SWNTs are usually a mixture of semiconducting and metallic ones. Despite of the higher content of semiconducting components in mixed SWNTs, metallic properties are predominantly expressed due to the bundling issue of the SWNT during the fabrication process, limiting the applicability to bio-transistor application. Here, we present a multi-scale semiconducting electronic film of SWNTs as a transducing platform for electrochemical field-effect-transistor (eFET) suitable for the sensitive detection of subtle biological modulation. A genetically engineered filamentous M13 phage showing strong binding affinity toward SWNTs on its body surface was used as a biological material, allowing us to fabricate a large-scale transparent semiconducting nanocomposite. As the relative ratio of SWNT to M13 phage decreases, the on–off ratio of SWNT electronic film increases by 1200%. To show broad applicability, the multi-scale SWNT nanomesh-based eFET is applied for monitoring a variety of biological reactions in association with enzymes, aptamers, and even cyanobacteria. The biomimetic electronic material system with the capability of transducing biological responses at a large scale over a broad dynamic range holds excellent promise for biosensors, biofuel cells, and environment monitoring.

We report the use of face mask materials as a carbon precursor for the synthesis of multi- and single-walled carbon nanotubes (CNTs) in an open-loop chemical recycling process. Novel surgical mask precursors were suspended in toluene and injected into a chemical vapor deposition reactor previously optimized for CNT production using liquid injection. The CNTs were collected and characterized using resonant Raman spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) before being turned into fibrils that were tested for electrical conductance. Once confirmed and repeated for statistical accuracy, a CNT-based Ethernet cable was manufactured and tested using iPerf3 for uplink and downlink speeds exceeding broadband standards worldwide. Radial breathing modes from Raman spectroscopy indicate single walled CNTs (SWCNTs) with diameters ranging from 0.8 to 1.55 nm and this matches well with TEM observations of SWCNTs with 1.5 nm diameter. This work pushes the horizon of feedstocks useful for CNT and SWCNT production in particular; this work demonstrates upcycling of materials fated for disposal into materials with positive net value and plenty of real-world applications.

An electrical double-layer capacitor is fabricated with biomass-derived activated carbon (AC) and multi-walled carbon nanotubes (MWCNTs), which are synthesized from Pongamia pinnata fruit shell and its seed oil, respectively. The activated carbon is produced by the chemical activation process at varying carbonization temperatures from 600 to 900 °C for 5 h at a rate of 10 min in an N2 atmosphere. The surface area of activated carbon and MWCNTs is 1170 m2 g− 1 and 216 m2 g− 1, respectively. The total pore volumes of activated carbon and MWCNTs are 1.51 cm3 g− 1 and 0.5907 cm3 g− 1, respectively. The as-prepared AC and MWCNTs are characterized by surface area analysis Brunner–Emmett–Teller method (BET), X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopic analysis, field emission scanning electron microscopy, high-resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy. The electrochemical performances of AC-AC, MWCNTs-MWCNTs and AC-MWCNTs (25:75) symmetric electrodes are studied by cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy. The AC-MWCNTs (25:75) single electrode performance is also studied in two different electrolytes, such as 0.5 M Na2SO4 and 0.5 M H2SO4. The fabricated AC-MWCNTs (25:75) symmetric supercapacitor cell exhibits excellent electrochemical performance in 0.5 M Na2SO4. It shows a specific capacitance of 55.51 Fg− 1, energy density 4.852 Wh Kg− 1 and power density of 199.18 W Kg− 1 at a current density of 1 Ag− 1 in the voltage window of 0–1.8 V. The AC-AC and AC-MWCNTs (25:75) symmetric supercapacitor electrodes show outstanding performance.

본 연구는 다중벽 탄소나노튜브(MWCNT)로 보강된 복합재 구조의 동적 해석을 다루었다. Mori-Tanaka 모델을 기반으 로 MWCNT 중량 비율, 패널의 곡률, 그리고 CNT의 임의 배열이 복합재의 동적거동에 미치는 상호작용을 연구하였다. 본 연구 결과는 CNT의 부피함유비율의 변화에 따른 복합재의 유효탄성계수를 예측하는 기존 문헌결과와 비교하여 검증하였다. 수치해 석 예제는 복합재의 동적 특성을 평가함에 있어서 MWCNT 보강의 불규칙한 배열 또는 기울어진 방향으로 배치된 효과에 대한 중요성을 제시하였다.

Individual multi-walled carbon nanotubes (MWCNTs) were exposed to the electron beam of 200 kV energy and high resolution transmission electron micrographs were recorded at several time intervals. Interestingly, the nucleation of diamond nanoparticles with in the highly disordered MWCNT matrix upon electron-irradiation is observed. This happens without any assistance of high pressures and temperatures. High pressure X-ray diffraction experiments were performed on core/shell structures which suggest that even the closed structures of carbon resist any inward pressure, thereby ruling out the possibility of a hypothetical internal pressure under the electron irradiation conditions. Our experiments suggest that the transformation of graphitic carbon into diamond in the size window of a few nanometers is possible due to the stability of the diamond and a selective dissolution effect of 200 kV electrons on graphite. A mechanism for the same is proposed.

Multi-walled carbon nanotubes (MWCNTs) grown by chemical vapor deposition retain the residual catalyst particles from which the growth occurred, which are considered a detriment to MWCNTs’ performance, especially electrical conductivity. The first direct measurements have been made of the electrical transport through the catalyst cap into the MWCNT using nanoscale 2-point-probe to determine the effects of the catalyst particle’s size and the diameter ratio with its associated MWCNT on the electrical transport through the catalyst cap as compared to the inherent conductivity of the MWCNT. The MWCNT diameter is independent of the catalyst size, but the ratio of the catalyst cap diameter to MWCNT diameter (DC/DNT) determines the conduction mechanism. Where DC/DNT is greater than 1 the resulting I–V curve is near ohmic, and the conduction through the catalyst ( RC+NT) approaches that of the MWCNT (RNT); however, when the DC/DNT < 1 the I–V curves shift to rectifying and RC+NT > > RNT. The experimental results are discussed in relation to current crowding at the interface between catalyst and nanotube due to an increased electric field.

In this study, epoxy composites were reinforced with multi-walled carbon nanotubes and fused silica particles, dispersing the fillers within the epoxy resin based on a simple physical method using only shear mixing and ultrasonication. The hybrid composite specimens with 0.6 wt% of carbon nanotubes and 50 wt% of silica particles showed improved mechanical properties, with increase in tensile strength and Young’s modulus up to 12 and 37%, respectively, with respect to those of the baseline specimens. The experimental results showed that the low thermal expansion of the silica particles improved the thermal stability of the composites compared with that of the baseline specimen, whereas the thermal expansion slightly increased, due to the increased heat transfer from the exterior to the interior of specimens by the carbon nanotube filler. The coefficient of thermal expansion of the hybrid composite specimen reinforced with 0.6 wt% of carbon nanotubes and 50 wt% of silica particles was decreased by 25%, and the thermal conductivity was increased by about 84%, compared with those of the baseline specimen.

Multi-walled carbon nanotubes (MWNTs) are suitable for delivering large biomolecules with lower cytotoxicity values and low prime cost. Surface modifications of MWNTs affect interaction with cells and proteins. Oxidation with strong acids decreases cytotoxicity of CNTs and increases protein-loading capacity. Here, after oxidation, TEM images revealed more aligned structure and carboxylated groups at the surface which decreases toxicity. Functionalized MWNTs showed more gradual degradation than the pristine MWNTs and mass loss increased by 2% in the same temperature range. Raman spectroscopy corrected graphitic structure with characteristic D and G bands at 1330 and 1579 cm−1 and increased intensity after oxidation. FTIR spectroscopy peaks at 1443 cm−1, 1560, 1640 cm−1, 2100–2200 cm−1 and 3426 cm−1 are ascribed to C–O–C vibrational stretch, C=C bonds, vibration of C≡C bonds and stretch of hydroxyl groups, respectively. The sonicationdriven dispersion of in phosphate-buffered saline, distilled water and cell culture medium were detected by UV–vis–NIR spectroscopy, water-dispersed functionalized MWNTs revealed the highest absorbance value. Cytotoxicity of MWNTs was investigated before and after functionalization in breast cancer (MDA-MB-231) and human vein endothelial (HUVEC) cells. Relatively low-toxicity results were obtained in functionalized MWNTs and cellular uptake of MWNTs were corrected with fluorescent imaging of cells and cell lysates. Protein-loading capacity of fsMWNTs (functionalized short-length multi-walled carbon nanotubes) was evaluated by using bovine serum albumin (BSA) and with an equal amount of fsMWNTs and BSA; 36% binding yield was obtained. Protein corona after covalent functionalization potentially lowered cytotoxicity up to 6%.

The carboxylated multi-walled carbon nanotubes (MWCNTs–COOH) were used as adsorbent for the separation of flavonoids (naringin and rutin) from bitter orange peel. The influence of the parameters such as, pH values, contact time, and desorption conditions was investigated. The samples were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, derivative thermogravimetric, scanning electron microscopy, UV–Vis spectroscopy, and high-performance liquid chromatography. After separation and desorption process, the eluent was injected for chromatography analysis. Under the optimal conditions, experimental results showed that the extraction efficiency of rutin was higher than naringin and other compounds. Moreover, the desorption percentage of flavonoids was calculated 83.6% after four cycles. This research confirmed that this method for separation of flavonoids is simple and less cost. In addition, the separated flavonoids can be used as antioxidant for the future applications.

Effects of multi-walled carbon nanotube (MWCNT) type and flow type (shear and elongational flow) on the electrical conductivity of polycarbonate (PC)/MWCNT nanocomposites were investigated. Two different MWCNTs produced a huge difference in electrical conductivity in an injection molded PC/MWCNT nanocomposite. It was observed that MWCNTs having a higher aspect ratio provide much lower electrical conductivity in injection molded PC/MWCNT nanocomposites while the conductivities of compression molded samples from two different MWCNTs were the same. We found that this is due to a difference in the deformability of the two MWCNTs. Nanocomposite samples prepared at a higher extensional rate and shear rate showed lower electrical conductivity. This is attributed to flow induced orientation of the MWCNTs. The experimental results were discussed in relation to variation in the tube–tube contact due to the change of the MWCNT orientation.

Carboxylated multi-wall carbon nanotubes (MWCNTs-COOH) have been used as efficient adsorbents for the removal of picric acid from aqueous solutions under stirring and ultrasound conditions. Batch experiments were conducted to study the influence of the different parameters such as pH, amount of adsorbents, contact time and concentration of picric acid on the adsorption process. The kinetic data were fitted with pseudo-first order, pseudo-secondorder, Elovich and intra-particle diffusion models. The kinetic studies were well described by the pseudo-second-order kinetic model for both methods. In addition, the adsorption isotherms of picric acid from aqueous solutions on the MWCNTs were investigated using six two-parameter models (Langmuir, Freundlich, Tempkin, Halsey, Harkins-Jura, Fowler- Guggenheim), four three-parameter models (Redlich-Peterson, Khan, Radke-Prausnitz, and Toth), two four-parameter equations (Fritz-Schlunder and Baudu) and one five-parameter equation (Fritz-Schlunder). Three error analysis methods, correlation coefficient, chi-square test and average relative errors, were applied to determine the best fit isotherm. The error analysis showed that the models with more than two parameters better described the picric acid sorption data compared to the two-parameter models. In particular, the Baudu equation provided the best model for the picric acid sorption data for both methods.

In this study, Fe-Ni bimetallic catalyst supported on kaolin is prepared by a wet impregnation method. The effects of mass of kaolin support, pre-calcination time, pre-calcination temperature and stirring speed on catalyst yields are examined. Then, the optimal supported Fe-Ni catalyst is utilised to produce multi-walled carbon nanotubes (MWCNTs) using catalytic chemical vapour deposition (CCVD) method. The catalysts and MWCNTs prepared using the optimal conditions are characterized using high resolution transmission electron microscope (HRTEM), high-resolution scanning electron microscope (HRSEM), electron diffraction spectrometer (EDS), selected area electron diffraction (SAED), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), and X-ray diffraction (XRD). The XRD/EDS patterns of the prepared catalyst confirm the formation of a purely crystalline ternary oxide (NiFe2O4). The statistical analysis of the variance demonstrates that the combined effects of the reaction temperature and acetylene flow rate predominantly influenced the MWCNT yield. The N2 adsorption (BET) and TGA analyses reveal high surface areas and thermally stable MWCNTs. The HRTEM/HRSEM micrographs confirm the formation of tangled MWCNTs with a particle size of less than 62 nm. The XRD patterns of the MWCNTs reveal the formation of a typical graphitized carbon. This study establishes the production of MWCNTs from a bi-metallic catalyst supported on kaolin.

The reportedly synergistic effects of carbon nanotubes (CNTs) and graphene hybrids have prompted strong demand for an efficient modifier to enhance their dispersion. Here, we investigated the ability of poly(acrylonitrile) (PAN) to overcome the van der Waals interaction of multi-walled CNTs (MWCNTs) and graphene by employing a simple wrapping process involving ultrasonication and subsequent centrifugation of PAN/MWCNT/graphene solutions. The physical wrapping of MWCNTs and graphene with PAN was investigated for various PAN concentrations, in an attempt to simplify and improve the polymer-wrapping process. Transmission electron microscopy analysis confirmed the wrapping of the MWCNTs and graphene with PAN layers. The interaction between the graphitic structure and the PAN molecules was examined using proton nuclear magnetic resonance, ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and Raman spectroscopy. The obtained results revealed that the cyano groups of the PAN molecules facilitated adhesion of the PAN molecules to the MWCNTs and graphene for polymer wrapping. The resulting enhanced dispersion of MWCNTs and graphene was verified from zeta potential and shelf-life measurements.

탄소나노튜브(MWCNT)는 그 구조적 특징에 따라 열적, 기계적 안정성이 우수하며 고분자 매트릭스 내에 소량만 첨가하여도 향상된 물성을 얻을 수 있다. 그러나 탄소나노튜브를 고분자 복합체에 응용 시 분산이 필수적으로 요구되기 때문에 전처리 기술이 필요하다. 본 연구에서는 PEO 막의 CO2 투과도 향상을 위해 PEO/EVA 혼합물에 산처리를 통해 표면에 친수성기가 도입된 다중벽 탄소나노튜브(MWCNT-COOH)를 첨가하여 PEO/EVA/MWCNT 혼성막을 제조하였다. 제조된 혼성막의 특성을 FT-IR, TGA, SEM 분석으로 확인하였다.