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Lung toxicity of carbon nanotubes (CNTs) is matter of concern since very long time. However, their mechanism of toxicity is still not yet well defined. In this work, the role of structural defects as organic stressors of CNTs able to trigger their potential toxicity is investigated. Four commercial CNTs, with different carbon purity grade, are morphologically characterized by transmission electron microscopy (TEM) and the relative amount of structural defects are estimated through Raman spectroscopy, by measuring the intensity ratio D/G (I D /I G ). The oxidative potential of CNTs is evaluated with cytochrome-C assay and reactive oxygen species (ROS) detection. Data show that CNTs with larger amounts of structural defects (higher I D /I G ratio) induce an increased ROS generation and consequent cytotoxicity and cellular damage, shown by TEM images of CNTs-cells interaction. Raman analyses of cells exposed to CNTs point out that the spectra of the CNTs inside the cells show no differences with respect of the signal recorded for cell-free CNTs, evidencing their biopersistence in lung cells. Raman spectra cannot provide direct indication of the existence of metals as impurity. It follows that the intensity ratio I D /I G can be taken as a predictive marker of the toxicity of a given CNT., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Traumatic Brain Injury, one of the significant causes of mortality and morbidity, affects worldwide and continues to be a diagnostic challenge. The most desirable and partially met clinical need is to simultaneously detect the disease-specific-biomarkers in a broad range of readily available body fluids on a single platform with a rapid, low-cost, ultrasensitive and selective device. Towards this, an array of interdigitated microelectrodes was fabricated on commercially existing low-cost single-side copper cladded printed-circuit-board substrate followed by the bioelectrodes preparation through covalent immobilization of brain injury specific biomarkers on carboxylic functionalized multi-walled carbon nanotubes embedded polypyrrole nanocomposite modified interdigitated microelectrodes. Subsequently, the immunological binding events were transduced as the normalized change in bioelectrode resistance with and without the target analyte via current-voltage analysis. As proof of concept, current-voltage responses were primarily recorded using a conventional probe station, and later, a portable handheld-electronic-readout was developed for the point-of-care application. The data compilation and analysis were carried out using the in-house developed android-based mobile app. Notably, the smartphone powered the readout through a PL-2303 serial connector, avoiding integrating power sources with the readout. Further, this technology can be adapted to other point-of-care biosensing applications., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

In this study, top-down syntheses of carbon dots (CDs) from four different carbon precursors, namely, carbon nano powders, graphite, graphene, and carbon nanotubes, were carried out. Systematic study demonstrated that the optical properties and surface functionalities of the CDs were quite similar and mainly influenced by the synthesis method, while the sizes, morphologies, chemical compositions, and core structures of the CDs were heavily influenced by the carbon precursors. On the basis of these studies, the formation processes and structural models of these four top-down CDs were proposed. The cell cytotoxicity and photothermal conversion efficiency of these CDs were also carefully evaluated, demonstrating their potential applications in photothermal therapy.

Using biocompatible polymer nanofibrous conduits with a controlled drug delivery have attracted much attention for peripheral nerve regeneration. This work was aimed at preparing electrospun poly (l-lactide-co-D, l-lactide) (PLDLLA) containing multi-walled carbon nanotubes (MWCNTs) and 4-aminopyridine (4-AP)-loaded molecularly imprinted nanoparticles (MIP 4-AP ) as well as evaluating their performance in in vitro and in vivo assessments. After synthesis of MIP 4-AP based on poly (methacrylic acid) with imprinting factor of 1.78, it was incorporated into the PLDLLA/MWCNTs nanofibers to optimize. By adjusting the process variables, the average diameter and electrical conductivity of the nanofibrous sample were 92 nm and 2870 × 10 -7  S cm -1 , respectively. Afterward, 4-AP release of the optimum sample showed the presence of MIP 4-AP leading to initial burst release decrease and plateau level postpone up to 96 h. Moreover, the culture results of PC12 as neuroblastoma cell line on optimal PLDLLA/MWCNTs/MIP 4-AP nanofibrous sample revealed the highest cell proliferation without cytotoxicity compared to neat nanofibers. Eventually, the animal model experiment exhibited that the conductive conduit based on the optimum sample was able to repair the rat's sciatic nerve after four weeks in accordance with sciatic function index and histological studies., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Carbon nanotubes (CNTs) have attracted significant interest for various applications owing to their superior physicochemical properties. The unzipping of multi-walled carbon nanotubes was accomplished by strong acid treatment. The solution of unzipped carbon nanotubes (u-CNTs) was homogeneous and stable. The u-CNTs were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis. The dimensions and morphologies of the synthesized u-CNTs were examined by transmission electron microscopy and scanning electron microscopy. The u-CNTs exhibited increased zeta potential and diameter compared with pure CNTs. A decrease in the thermal stability was observed in the u-CNTs compared with pure CNTs. The u-CNTs exhibited better biocompatibility than pure CNTs in the presence of bone marrow-derived mesenchymal stem cells, showing improved biocompatibility. The u-CNT-treated media generated lower amounts of reactive oxygen species than pure CNTs. Enhanced mineralization was observed in the u-CNT-treated groups compared with the pure CNTs and the control, indicating its better osteogenic potential. The upregulation of osteogenic-associated gene markers in u-CNT groups compared with pure CNTs confirms their superior osteogenic potential. Thus, u-CNTs are potential candidates for tissue engineering applications, especially bone tissue., (© 2021 Wiley Periodicals LLC.)

Carbon nanotubes (CNTs) are cylindrical nanostructures and have unique properties, including flexibility, electrical conductivity, and biocompatibility. We focused on CNTs fabricated with the carbon nanotube yarns (cYarn) as a possible substrate promoting peripheral nerve regeneration with these properties. We bridged a 15 mm rat sciatic nerve defect with five different densities of cYarn. Eight weeks after the surgery, the regenerated axons crossing the CNTs, electromyographical findings, and muscle weight ratio of the lower leg showed recovery of the nerve function by interfacing with cYarn. Furthermore, the sciatic nerve functional index (SFI) at 16 weeks showed improvement in gait function. A 2% CNT density tended to be the most effective for nerve regeneration as measured by both histological axonal regeneration and motor function. We confirmed that CNT yarn promotes peripheral nerve regeneration by using it as a scaffold for repairing nerve defects. Our results support the future clinical application of CNTs for bridging nerve defects as an off-the-shelf material., (© 2021. The Author(s).)

Myocardial infarction of cardiomyocytes is a leading cause of heart failure (HF) worldwide. Since heart has very limited regeneration capacity, cardiac tissue engineering (TE) to produce a bioactive scaffold is considered. In this study, a series of polyurethane solutions (5-7%wt) in aqueous acetic acid were prepared using electrospinning. A variety of Polyurethane (PU)/Chitosan (Cs)/carbon nanotubes (CNT) composite nanofibrous scaffolds with random and aligned orientation were fabricated to structurally mimic the extracellular matrix (ECM). Electrospun nanofibers were then characterized using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), water contact angle, degradation studies, tensile tests, electrical resistance measurement and cell viability assay. The biocompatibility of electrospun random and aligned nanofibrous scaffolds with H9C2 Cells was confirmed. The results revealed that fabricated PU/Cs/CNT composite nanofibrous scaffolds were electro-conductive and aligned nanofibers could be considered as promising scaffolds with nano-scale features for regeneration of infarcted myocardium., Competing Interests: Declaration of competing interest The authors certify that there is no conflict of interest in this study., (Copyright © 2021. Published by Elsevier B.V.)

Solubilization of carbon nanotubes (CNTs) is a fundamental technique for the use of CNTs and their conjugates as nanodevices and nanobiodevices. In this work, we demonstrate the preparation of CNT suspensions with "green" detergents made from coconuts and bamboo as fundamental research in CNT nanotechnology. Single-walled CNTs (SWNTs) with a few carboxylic acid groups (3-5%) and pristine multi-walled CNTs (MWNTs) were mixed in each detergent solution and sonicated with a bath-type sonicator. The prepared suspensions were characterized using absorbance spectroscopy, scanning electron microscopy, and Raman spectroscopy. Among the eight combinations of CNTs and detergents (two types of CNTs and four detergents, including sodium dodecyl sulfate (SDS) as the standard), SWNTs/MWNTs were well dispersed in all combinations except the combination of the MWNTs and the bamboo detergent. The stability of the suspensions prepared with coconut detergents was better than that prepared with SDS. Because the efficiency of the bamboo detergents against the MWNTs differed significantly from that against the SWNTs, the natural detergent might be useful for separating CNTs. Our results revealed that the use of the "green" detergents had the advantage of dispersing CNTs as well as SDS.

Single-walled carbon nanotubes (SWCNTs) emerge as promising novel carbon-based nanoparticles for use in biomedicine, pharmacology and precision agriculture. They were shown to penetrate cell walls and membranes and to physically interact and exchange electrons with photosynthetic complexes in vitro. Here, for the first time, we studied the concentration-dependent effect of foliar application of copolymer-grafted SWCNTs on the structural and functional characteristics of intact pea plants. The lowest used concentration of 10 mg L -1 did not cause any harmful effects on the studied leaf characteristics, while abundant epicuticular wax generation on both leaf surfaces was observed after 300 mg L -1 treatment. Swelling of both the granal and the stromal regions of thylakoid membranes was detected after application of 100 mg L -1 and was most pronounced after 300 mg L -1 . Higher SWCNT doses lead to impaired photosynthesis in terms of lower proton motive force generation, slower generation of non-photochemical quenching and reduced zeaxanthin content; however, the photosystem II function was largely preserved. Our results clearly indicate that SWCNTs affect the photosynthetic apparatus in a concentration-dependent manner. Low doses (10 mg L -1 ) of SWCNTs appear to be a safe suitable object for future development of nanocarriers for substances that are beneficial for plant growth.

High-performance flexible strain sensors are urgently needed with the rapid development of wearable intelligent electronics. Here, a bifiller of carbon nanotubes (CNTs) and graphene (GR) for filling flexible porous polydimethylsiloxane (CNT-GR/PDMS) nanocomposites is designed and prepared for strain-sensing applications. The typical microporous structure was successfully constructed using the Soxhlet extraction technique, and the connected CNTs and GR constructed a perfect three-dimensional conductive network in the porous skeleton. As a result, the stretchability and sensitivity of the CNT-GR/PDMS-based strain sensors were well regulated based on the porous structure and the typical synergistic conductive network. Based on the destruction effect of the brittle synergistic conductive network located in the outer and inner layers of the cell skeleton and the contact effect between adjacent cells in different strain ranges, the prepared CNTs-GR/PDMS-based strain sensor exhibited superior gauge factors of 182.5, 45.6, 70.2, and 186.5 in the 0-3, 3-57, 57-90, and 90-120% strain regions, respectively. In addition, this material also exhibited an ultralow detection limit (0.5% strain), a fast response time (60 ms), good stability and durability (10,000 cycles), and frequency-/strain-dependent sensing performances, making it active for the detection of various external environments. Finally, the prepared porous CNTs-GR/PDMS-based strain sensor was attached to the skin to detect various human motions, such as wrist bending, finger bending, elbow bending, and knee bending, thereby demonstrating wide application prospects in smart wearable devices.

Doxorubicin (DOX), a recognized anticancer drug, forms stable associations with carbon nanotubes (CNTs). CNTs when properly functionalized have the ability to anchor directly in cancerous tumors where the release of the drug occurs thanks to the tumor slightly acidic pH. Herein, we study the armchair and zigzag CNTs with Stone-Wales (SW) defects to rank their ability to encapsulate DOX by determining the DOX-CNT binding free energies using the MM/PBSA and MM/GBSA methods implemented in AMBER16. We investigate also the chiral CNTs with haeckelite defects. Each haeckelite defect consists of a pair of square and octagonal rings. The armchair and zigzag CNT with SW defects and chiral nanotubes with haeckelite defects predict DOX-CNT interactions that depend on the length of the nanotube, the number of present defects and nitrogen doping. Chiral nanotubes having two haeckelite defects reveal a clear dependence on the nitrogen content with DOX-CNT interaction forces decreasing in the order 0N > 4N > 8N. These results contribute to a further understanding of drug-nanotube interactions and to the design of new drug delivery systems based on CNTs.

In anaerobic bioreactors, the electrons produced during the oxidation of organic matter can potentially be used for the biological reduction of pharmaceuticals in wastewaters. Common electron transfer limitations benefit from the acceleration of reactions through utilization of redox mediators (RM). This work explores the potential of carbon nanomaterials (CNM) as RM on the anaerobic removal of ciprofloxacin (CIP). Pristine and tailored carbon nanotubes (CNT) were first tested for chemical reduction of CIP, and pristine CNT was found as the best material, so it was further utilized in biological anaerobic assays with anaerobic granular sludge (GS). In addition, magnetic CNT were prepared and also tested in biological assays, as they are easier to be recovered and reused. In biological tests with CNM, approximately 99% CIP removal was achieved, and the reaction rates increased ≈1.5-fold relatively to the control without CNM. In these experiments, CIP adsorption onto GS and CNM was above 90%. Despite, after applying three successive cycles of CIP addition, the catalytic properties of magnetic CNT were maintained while adsorption decreased to 29 ± 3.2%, as the result of CNM overload by CIP. The results suggest the combined occurrence of different mechanisms for CIP removal: adsorption on GS and/or CNM, and biological reduction or oxidation, which can be accelerated by the presence of CNM. After biological treatment with CNM, toxicity towards Vibrio fischeri was evaluated, resulting in ≈ 46% detoxification of CIP solution, showing the advantages of combining biological treatment with CNM for CIP removal.

Present study described a sensitive and efficient method for determination of heterocyclic aromatic hydrocarbons using multiwalled carbon nanotubes modified magnetic polyamido-amine dendrimers (MNPs@PAMAM-Gn@MWCNTs) as adsorbent for magnetic solid-phase extraction (MSPE) coupled with gas chromatography-triple quadrupole mass spectrometer (GC-MS/MS). Some pivotal parameters including PAMAM generation, adsorbent dosage, adsorption time, elution time and volume, pH and humic acid concentration were investigated to achieve the best adsorption efficiencies. Under the optimal conditions, 7-methylquinoline, dibenzothiophene and carbazole had good linearity in the concentration range of 0.005-20 μg L  -   1 , 9-methylcarbazole, 4-methyldibenzothiophene and 4,6-dimethyl dibenzothiophene had good linearity in the concentration range of 0.001-20 μg L  -   1 . All the correlation coefficients were higher than 0.996. The detection limits of the targets were in the range of 2.2 × 10 -4 -1.8 × 10 -3  μg L  -   1 with precisions less than 8.28% (n = 6). The enrichment factors were in the range of 141-147. The spiked recoveries were in the range of 87.0%-115.1% (n = 3). These results indicated that the method could be a reliable alternative tool for monitoring trace heterocyclic aromatic hydrocarbons in environmental water samples., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The retention behavior of a series of acidic drugs, namely ketoprofen (KET), naproxen (NAP), diclofenac (DIC), and ibuprofen (IBU), on the heat-resisting ZORBAX 300SB-C 18 column, was studied thermodynamically using high-temperature liquid chromatography (HTLC). A perfect correlation of the compounds' lipophilicity and the calculated thermodynamic indicators evidenced its contribution to the retention behavior. Besides, the steric fitting has a subsidiary effect on IBU retention. Isocratic HTLC separation of the four compounds was achieved using an aqueous mobile phase containing 30% acetonitrile-0.2% acetic acid-0.2% triethylamine at 60 °C. This method has been utilized to monitor the adsorption efficiency of multiwalled carbon nanotubes (MWCNTs) for the removal of the four NSAIDs from water. Different variables affecting the remediation process have been optimized such as the time of contact, pH, ionic strength, temperature, and the mass of MWCNTs. The kinetics and thermodynamics of the adsorption were investigated. The adsorption was evidenced to take place via pseudo-second-order kinetics and the intraparticle diffusion is the rate-controlling step. The thermodynamic investigation showed that the adsorption process is exothermic and enthalpy-driven, and the adsorption is more extensive at a lower temperature. The MWCNTs showed excellent adsorption efficiency of about 76.4 to 97.6% at the optimum conditions. The obtained results are promising and encouraging for the full-scale application of MWCNTs for remediation of NSAIDs-related water pollution. The green analytical chemistry metric "AGREE" and the analytical eco-scale score tool confirmed that the developed protocol is greener and more favorable to the environment and user than most of the reported literature., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021. Published by Elsevier B.V.)

Metal organic framework (MOF)-derived carbon nanostructures (MDC) synthesized by either calcinations or carbonization or pyrolysis are emerging as attractive materials for a wide range of applications like batteries, super-capacitors, sensors, water treatment, etc. But the process of transformation of MOFs into MDCs is time-consuming, with reactions requiring inert atmospheres and reaction time typically running into hours. In this manuscript, we report the transformation of 1,4-diazabicyclo[2.2.2]octane, (DABCO)-based MOFs into iron nitride nanoparticles embedded in nitrogen-doped carbon nanotubes by simple, fast and facile microwave pyrolysis. By using graphene oxide and carbon fiber as microwave susceptible surfaces, three-dimensional nitrogen-doped carbon nanotubes vertically grown on reduced graphene oxide (MDNCNT@rGO) and carbon fibers (MDCNT@CF), respectively, were obtained, whose utility as anode material in sodium-ion batteries (MDNCNT@rGO) and for EMI (electromagnetic interference) shielding material (MDCNT@CF) is reported.

Lead contamination in drinking and natural water has reached alarming concentrations, thus necessitating the development of accurate and rapid determination systems for Pb(II) in aqueous systems. Two hyphenated flow injection-solid phase extraction- FAAS (FI-SPE-FAAS) systems using oxidized and m-phenylenediamine functionalized multiwalled carbon nanotubes for Pb(II) preconcentration from industrially contaminated real water samples have been proposed. The chemical and hydrodynamic parameters affecting Pb(II) sorption/desorption were optimized. The effect of common interfering ions in water was also studied. Different figures of merit such as preconcentration factor (> 70), detection limit (≤ 1.5 µg L -1 ), and relative standard deviation (≤ 1.3%) were achieved at the preconcentration time of 120 s for both the preconcentration systems. The method was applied to industrially contaminated real water samples and the spike recovery tests were carried out using standard Pb(II) solution traceable to NIST. The proposed method was validated using standard reference material 1640a supplied by NIST Gaithersburg, MD, USA., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021. Published by Elsevier B.V.)

Flexible paper-based sensors may be applied in numerous fields, but this requires addressing their limitations related to poor thermal and water resistance, which results in low service life. Herein, we report a paper-based composite sensor composed of carboxylic carbon nanotubes (CCNTs) and poly- m -phenyleneisophthalamide (PMIA), fabricated by a facile papermaking process. The CCNT/PMIA composite sensor exhibits an ability to detect pressures generated by various human movements, attributed to the sensor's conductive network and the characteristic "mud-brick" microstructure. The sensor exhibits the capability to monitor human motions, such as bending of finger joints and elbow joints, speaking, blinking, and smiling, as well as temperature variations in the range of 30-90 °C. Such a capability to sensitively detect pressure can be realized at different applied frequencies, gradient sagittas, and multiple twists with a short response time (104 ms) even after being soaked in water, acid, and alkali solutions. Moreover, the sensor demonstrates excellent mechanical properties and hence can be folded up to 6000 times without failure, can bear 5 kg of load without breaking, and can be cycled 2000 times without energy loss, providing a great possibility for a long sensing life. Additionally, the composite sensor shows exceptional Joule heating performance, which can reach 242 °C in less than 15 s even when powered by a low input voltage (25 V). From the perspective of industrialization, low-cost and large-scale roll-to-roll production of the paper-based sensor can be achieved, with a formed length of thousands of meters, showing great potential for future industrial applications as a wearable smart sensor for detecting pressure and temperature, with the capability of electric heating.

Carbon nanohorns (CNHs), a type of nanocarbon, have been studied for the application of drug delivery systems (DDSs) because they are easily functionalized, support bone regeneration, can be used to perform photohyperthermia, have low toxicity, and are easily phagocytosed by macrophages. To take advantage of these features of CNHs, we developed a DDS for the local treatment of bone metastasis by loading the antibone resorption drug ibandronate (IBN) onto CNHs. The poor adsorption of IBN onto CNHs due to the weak hydrophilic-hydrophobic interaction was overcome by using calcium phosphates (CaPs) as mediators. In the fabrication process, we used oxidized CNH (OxCNH), which is less hydrophobic, onto which IBN was coprecipitated with CaP from a labile supersaturated CaP solution. OxCNH-CaP-IBN composite nanoparticles exerted stronger cell-suppressive effects than OxCNH and IBN in both murine macrophages (RAW264.7 cells) and osteoclasts (differentiated from RAW264.7 cells). OxCNH-CaP-IBN composite nanoparticles were efficiently phagocytosed by macrophage cells, where they specifically accumulated in lysosomes. The stronger cell-suppressive effects were likely due to intracellular delivery of IBN, i.e., the release of IBN from OxCNH-CaP-IBN composite nanoparticles via dissociation of CaP in the acidic environment of lysosomes. Our findings suggest that OxCNH-CaP-IBN composite nanoparticles are potentially useful for the local treatment of metastatic bone destruction.

Molecular magnets attached to carbon nanotubes (CNT) are being studied as potential candidates for developing spintronic and quantum technologies. However, the functionalization routes used to develop these hybrid systems can drastically affect their respective physiochemical properties. Due to the complexity of this systems, little work has been directed at establishing the correlation between the degree of functionalization and the magnetic character. Here, we demonstrate the chemical functionalization degree associated with molecular magnet loading can be utilized for controlled tuning the magnetic properties of a CNT-lanthanide hybrid complex. CNT functionalization degree was evaluated by interpreting minor Raman phonon modes in relation to the controlled reaction conditions. These findings were exploited in attaching a rare-earth-based molecular magnet (Gd-DTPA) to the CNTs. Inductively coupled plasma mass spectrometry, time-of-flight secondary ion mass spectrometry and super conducting quantum interference device (SQUID) measurements were used to elucidate the variation of magnetic character across the samples. This controlled Gd-DTPA loading on the CNT surface has led to a significant change in the nanotube intrinsic diamagnetism, showing antiferromagnetic coupling with increase in the Weiss temperature with respect to increased loading. This indicates that synthesis of a highly correlated spin system for developing novel spintronic technologies can be realized through a carbon-based hybrid material.

Graphene and phospholipids are widely used in biosensing and drug delivery. This paper studies the mechanical and electronic properties of a composite based on two graphene flakes and dipalmitoylphosphatidylcholine (DPPC) phospholipid molecules located between them via combination of various mathematical modeling methods. Molecular dynamics simulation showed that an adhesion between bilayer graphene and DPCC increases during nanoindentation of the composite by a carbon nanotube (CNT). Herewith, the DPPC molecule located under a nanotip takes the form of graphene and is not destroyed. By the Mulliken procedure, it was shown that the phospholipid molecules act as a "buffer" of charge between two graphene sheets and CNT. The highest values of electron transfer in the graphene/DPPC system were observed at the lower indentation point, when the deflection reached its maximum value.

The fused-deposition modeling (FDM) process is carried out at an elevated temperature, preventing the addition of biological factors, drugs, bioactive compounds, etc, during fabrication. To overcome this disadvantage, a 3D interlinked porous polylactic acid (PLA) scaffold was fabricated by FDM, followed by the embedding of a polycaprolactone (PCL) scaffold into the pores of the PLA at room temperature, yielding a PLA-PCL scaffold. In addition, PLA-PCL scaffolds with nanohydroxyapatite (PLA-PCL-nHAP) and multiwalled carbon nanotubes (PLA-PCL-MWCNT) were also fabricated. Here, the FDM-fabricated PLA scaffold functions as the structural component, whereas the embedded PCL scaffold acts as the functional component, which provides a the ability to functionalize the scaffolds with the desired chemical or biological materials. The embedding process is straightforward, cost effective, and does not require sophistication. A mechanical characterization of the scaffolds suggests that the Young's modulus of the PLA-PCL scaffold (16.02 MPa) was higher than that of the FDM-fabricated PLA (9.98 MPa) scaffold, by virtue of embedded PCL matrix. In addition, finite element analysis showed that the von Mises stress on a mandible with scaffolds was 4.04 MPa, whereas for a mandible with a defect, it was 6.7 MPa, confirming the stress distribution efficiency and mechanical stability of these scaffolds. Furthermore, field emission-scanning electron microscope analysis implied the presence of interlinked porous structures with pore diameters of 50 µm to 300 µm. X-ray diffraction results revealed an increased crystallinity (%) in the embedded models (PLA-PCL, PLA-PCL-nHAP and PLA-PCL-MWCNT), compared to a PLA printed scaffold. Additionally, Raman analysis revealed that the embedding process did not cause chemical alterations in the polymeric chains. In vitro analysis with human osteoblasts demonstrated the osteoconductive nature of the scaffold, which supported mineralization. In brief, the advantage of our model is that it helps to overcome the difficulties of manufacturing a filament with the desired additives for FDM, and offers the ability to incorporate the desired concentrations of heat-labile bioactive molecules during the embedding process at ambient temperatures.

Objective: This study aimed to investigate the effects of multiwalled carbon nanotubes (MWCNTs) on cytotoxicity and tumor metastasis in ovarian cancer cells, and further explored its mechanism., Results: MWCNTs significantly inhibited cell viability and the clone number, increased the cell number of S phage, promoted cell apoptosis, as well as suppressed cell migration and invasion, and damaged the structure of actin cytoskeleton in a dose-dependent manner in SKOV3. Moreover, MWCNTs treatment obviously damaged the structure of actin cytoskeleton of SKOV3, and inhibited the activities of mitochondrial electron transfer chain complexes I-V., Conclusions: MWCNTs might influence the assembly of actin cytoskeleton by disrupting mitochondrial function, thereby inhibiting migration and invasion of SKOV3., Methods: The characterization of MWCNTs was analyzed by UV visible light absorption spectroscopy and transmission electron microscopy. SKOV3 cells were exposed to different doses of MWCNTs. Then, in vitro cytotoxicity of MWCNTs was evaluated by MTT assay, colony-forming assay, cell cycle, and cell apoptosis assay. Moreover, the effects of MWCNTs on cell migration and invasion as well as actin cytoskeleton were explored in SKOV3 cells. Furthermore, the mitochondrial membrane potential and the activities of mitochondrial electron transfer chain complexes I-V were measured.

Here, we report that multi-walled carbon nanotubes (MWCNTs) can promote plant root hair growth in the species analyzed in this study; however, low and excessive concentrations of MWCNTs had no significant effect or even an inhibiting influence. Further results show that MWCNTs can enter rapeseed root cells. Meanwhile, nitrate reductase (NR)-dependent nitric oxide (NO) and ethylene syntheses, as well as root hair formation, were significantly stimulated by MWCNTs. Transcription of root hair growth-related genes were also modulated. The above responses were sensitive to the removal of endogenous NO or ethylene with a scavenger of NO or NO/ethylene synthesis inhibitors. Pharmacological and molecular evidence suggested that ethylene might act downstream of NR-dependent NO in MWCNTs-induced root hair morphogenesis. Genetic evidence in Arabidopsis further revealed that MWCNTs-triggered root hair growth was abolished in ethylene-insensitive mutants ein2-5 and ein3-1 , and NR mutant nia1/2 , but not in noa1 mutant. Further data placed NO synthesis linearly before ethylene production in root hair development triggered by MWCNTs. The above findings thus provide some insights into the molecular mechanism underlying MWCNTs control of root hair morphogenesis.

In the current study, eco-structured and efficient removal of the veterinary fluoroquinolone antibiotic sarafloxacin (SARA) from wastewater has been explored. The adsorptive power of four agro-wastes (AWs) derived from pistachio nutshells (PNS) and Aloe vera leaves (AV) as well as the multi-walled carbon nanotubes (MWCNTs) has been assessed. Adsorbent derived from raw pistachio nutshells (RPNS) was the most efficient among the four tested AWs (%removal '%R' = 82.39%), while MWCNTs showed the best adsorptive power amongst the five adsorbents (%R = 96.20%). Plackett-Burman design (PBD) was used to optimize the adsorption process. Two responses ('%R' and adsorption capacity ' q e ') were optimized as a function of four variables (pH, adsorbent dose 'AD' (dose of RPNS and MWCNTs), adsorbate concentration [SARA] and contact time 'CT'). The effect of pH was similar for both RPNS and MWCNTs. Morphological and textural characterization of the tested adsorbents was carried out using FT-IR spectroscopy, SEM and BET analyses. Conversion of waste-derived materials into carbonaceous material was investigated by Raman spectroscopy. Equilibrium studies showed that Freundlich isotherm is the most suitable isotherm to describe the adsorption of SARA onto RPNS. Kinetics' investigation shows that the adsorption of SARA onto RPNS follows a pseudo-second order (PSO) model.

A simple and efficient separation method of carrier-free 47 Sc from neutron irradiated titanium target using a novel chitosan-acrylic acid/multiwalled carbon nanotubes (CS-AA/MWCNTs) composite was established. The synthesis of the CS-AA/MWCNTs composite was achieved using gamma radiation-induced template polymerization. The grafting efficiency (GE%) of AA on CS onto the surface of f-MWCNTs reached a maximum of~84% under the optimized conditions (30 wt% CS, 1.0 wt% AA, 0.15 wt% f-MWCNTs, >0.2 wt% N,N'-Methylenebisacrylamide (NMBA), and irradiation dose ~25 kGy). Different analyses (FT-IR, SEM, TGA and DTA) were examined for confirming the structural morphology and mechanical properties of the new synthesized composite. Interestingly, the CS-AA/MWCNTs composite depicted a selective adsorption of Sc(III) rather than Ti(IV) ions at pH 5 with adsorption efficiency of ~93.93%. The ionic exchange separation of no-carrier-added (NCA) 47 Sc(III) from irradiated TiO 2 target on CS-AA/MWCNTs composite packed column efficiently eluted 47 Sc(III) by 91 ± 0.8% using 1 M HCl solution. The quality control tests (radionuclidic, radiochemical, and chemical purities) for the eluted 47 Sc(III) clarified its high purity and validity for cancer theranostics., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Multi-walled carbon nanotubes (MWCNT) play a synergistic role with conducting polymer in practical applications such as biological sensing. In this paper, multi-walled carbon nanotube and polypyrrole (PPy) composites were prepared on a fiber surface for the first time, and their morphology and electrical properties were characterized. Compared with PPy-coated fiber, the presence of carbon nanotubes induced the growth of large areas of PPy nanowires. In addition, fiber organic electrochemical transistors (FECTs) based on PPy and MWCNT were assembled, showing a higher on/off ratio, better stability, and greater flexibility. The lactate biosensor based on FECTs exhibits high sensitivity, with a correlation coefficient of R = 0.9889, quick response time of 0.6-0.8 s, a wide linear response range of 1 nM-1 mM, and excellent selectivity for lactate. Furthermore, the lactate concentration in human sweat was successfully detected by a FECT-based sensor. The hybrid fibers can be easily woven and placed on fabric simply by stitching. This favorable performance of the FECT-based sensor makes it suitable for noninvasive sensing of lactate. Therefore, it provides a promising platform for future use in healthcare and detection applications. Graphical abstract.

Modern high-resolution scanning electron microscopes (SEM), equipped with field emission guns (FEGs), designed to operate at low acceleration voltage, have opened new opportunities to study conductive or insulating systems, without conductive coating. Better electron sources, optics, vacuum, and detectors allow high-resolution SEM to serve as a powerful characterization and analytical tool, and provide invaluable information about structure-property relations of nanomaterials and related applications. Slight specimen charging can be exploited to enhance contrast between different materials and phases, with minimum imaging artifacts. Optimization of charging effects and improved micrograph contrast are essential for the study of different-scale features in ceramics, polymers, organic materials, and thermally fixed liquids, including in biological research. The operating SEM parameters can be adjusted to a specific specimen based on prior knowledge of interaction of the electron beam with similar specimens, and the type of information one wishes to acquire. In this work we examined the effect of the acceleration voltage and the use of different detectors on the contrast formation in several types of specimens, focusing on materials formed mainly of carbon and oxygen, with low inherent contrast in the SEM. That includes cryogenic SEM (cryo-SEM) to study emulsions in their native state. We also studied by cryo-SEM carbon nanotubes (CNTs) dispersed in water and dissolved in superacid. HR-SEM at room temperature was performed on CNT films, deposited on glass. We show how micrograph contrast changes with different detectors, at different acceleration voltages. Judicious selection of the SEM operation parameters leads to optimal picture contrast between domains of different composition., (Copyright © 2020 Elsevier B.V. All rights reserved.)

In this paper, nicotine (NIC) was detected by cyclic voltammetry (CV) using a modified glassy carbon (GC) electrode. To do this, the surface of the GC electrode was modified by hybrid nanofiber obtained from the electrospinning method. Hybrid nanofibers were produced through the dispersion of carboxylated multi-walled carbon nanotube (MWCNT-COOH) as an inorganic component in the chitosan (CS) polymer matrix as an organic component. The nanofibers showed unique morphology and high surface area value. With the increase of functionalized carbon nanotube content in the nanofibers, the mean pore diameter and average nanofiber diameter increased. The electrochemical properties of nanofibers towards the sensing of NIC were investigated by the CV method. NIC was irreversibly reduced with the use of a CS/MWCNT-COOH electrode, a controlled process with two protons and two electrons. An oxidation signal at lower potential with higher current was obtained for NIC with the use of a polymer-modified electrode compared to a GC electrode. This was as a result of the electrocatalytic effect of the hybrid nanofibers due to the ability of carbon nanotubes to increase the rate of electron transfer. Under optimum conditions, the oxidation of NIC occurred at 0.82 eV with a pH of 7.4. The linear calibration curve was in the concentration range of 0.1-100 μM NIC (R 2 = 0.9987) with a detection limit of 30 nM. For 100 parallel 10 μM NIC diagnoses for five replicates, 97.2% with a standard deviation of 4.08 maintained their stability over the first cycle. This indicates that the CS/MWCNT-COOH electrode has excellent reproducibility and stability.

Purpose: Although single-walled nanotubes (SWNTs) with functional groups have been suggested as a potential nanomedicine to treat neuronal disorders, effective routes to administer SWNTs have not been compared thus far. The blood-brain barrier is a considerable challenge for the development of brain-targeting drugs, and therefore functionalized SWNT routes of administration have been needed for testing Parkinson's disease (PD) treatment. Here, effective administration routes of functionalized SWNTs were evaluated in PD mouse model., Methods: Three different administration routes were tested in PD mouse model. Functionalized SWNTs were injected directly into the lateral ventricle three days before (Method 1) or after (Method 2) 6-hydroxydopamine (6-OHDA) injection to compare the protective effects of SWNTs against dopaminergic neuronal death or functionalized SWNTs were injected intravenously at three and four days after 6-OHDA injection (Method 3). Asymmetric behaviors and histological assessment from all animals were performed at two weeks after 6-OHDA injection., Results: Ventricular injections of SWNTs both before or after 6-OHDA exposure protected dopaminergic neurons both in the substantia nigra and striatum and alleviated rotational asymmetry behavior in PD mice. Moreover, intravenous administration of SWNTs three and four days after 6-OHDA injection also prevented neuronal death and PD mice behavioral impairment without apparent cytotoxicity after six months post-treatment., Conclusion: Our study demonstrates that functionalized SWNTs could effectively protect dopaminergic neurons through all administration routes examined herein. Therefore, SWNTs are promising nanomedicine agents by themselves or as therapeutic carriers to treat neuronal disorders such as PD., Competing Interests: The authors report no conflicts of interest in this work., (© 2020 Kim et al.)

The porous chitosan/carboxylated carbon nanotubes composite aerogels (CS-CCN) with different CCN contents were prepared for the efficient removal of U(VI) from aqueous solution. The successful formation of CS-CCN aerogels with highly porous structure was confirmed by different characterizations (such as SEM, TEM, XRD, etc.). The sorption capacity of the aerogels depends on CCN content, which has significant impact on the porous structure and the sorption ability of the aerogels. The CS-CCN aerogels were found to be very effective for U(VI) sorption: the maximum mono-layer sorption capacity for CS-CCN2 aerogel reached 307.5 mg/g at pH 5.0 and 298 K. The chemisorption or surface complexation through sharing of O/N lone pair electrons on the active sites (carboxylic and amine groups) was responsible for U(VI) sorption, which is confirmed by the IR and XPS analysis. Meanwhile, the good-fitting of both sorption kinetics by pseudo-second-order model and sorption isotherms by Langmuir model also indicates chemisorption mechanism. The thermodynamic data suggest that U(VI) sorption on CS-CCN aerogel is endothermic and spontaneous. The unique characteristics such as high sorption capacity, fast kinetic, and easy recovery from solution make CS-CCN aerogels be very efficient sorbents for the treatment of radioactive wastewater., Competing Interests: Declaration of competing interest The authors certify that they have NO affiliations with or involvement in any organization or entity with any financial interest (such as honoraria; educational grants; participation in speakers’ bureaus; membership, employment, consultancies, stock ownership, or other equity interest; and expert testimony or patent-licensing arrangements), or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript., (Copyright © 2020. Published by Elsevier B.V.)

Based on a hybrid carbon nanotube composite, a novel electrochemical sensor with high sensitivity and selectivity was designed for the simultaneous determination of dopamine (DA) and uric acid (UA). The hybrid carbon nanotube composite was prepared by ultrasonic assembly of carboxylated multi-walled carbon nanotube (MWCNT-COOH) and hydroxylated single-walled carbon nanotube (SWCNT-OH). And the hybrid (MWCNT-COOH/SWCNT-OH) composite was characterized by field emission scanning electron microscopy (FE-SEM) and Fourier transform infrared (FT-IR) spectroscopy. The electrochemical performances of MWCNT-COOH/SWCNT-OH composite modified glassy carbon electrode (MWCNT-COOH/SWCNT-OH/GCE) were analyzed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). Under the optimum experimental conditions, the as-prepared sensor showed high sensitivity and selectivity for DA and UA. The calibration curves obtained were linear for the currents versus DA and UA concentrations in the range 2-150 μM, and limits of detection (LODs) were calculated to be 0.37 μM and 0.61 μM (signal-to-noise ratio of 3, S/N = 3), respectively. The recoveries of DA and UA in bovine serum samples at MWCNT-COOH/SWCNT-OH/GCE were in the range 96.18-105.02%, and relative standard deviations (RSDs) were 3.34-7.27%. The proposed electrochemical sensor showed good anti-interference ability, excellent reproducibility and stability, as well as high selectivity, which might provide a promising platform for determination of DA and UA., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2020 Elsevier Inc. All rights reserved.)

A method is described for the functionalization of magnetic carbon nanotubes to recognize aristolochic acid Ⅰ and Ⅱ. 3-Glycidyloxypropyltrimethoxysilane was used as a coupling agent to immobilize adenine on a solid support. The morphology and structure of adenine-coated magnetic carbon nanotubes was investigated using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and a vibrating sample magnetometer (VSM). The adsorption performance of the adenine-coated magnetic carbon nanotubes was evaluated via adsorption isotherms, the kinetics and selectivity tests. The adsorption capacity of the adenine-functionalized sorbent for aristolochic acid Ⅰ was determined to be 24.5 μg mg -1 . By combining magnetic solid phase extraction with HPLC detection, a method was developed to enrich and detect aristolochic acids used in traditional Chinese medicine. A satisfactory recovery (92.7 - 97.5% for aristolochic acid Ⅰ and 92.6 - 99.4% for aristolochic acid Ⅱ) and an acceptable relative standard deviation (<4.0%) were obtained., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier B.V.)

With the increase in demand, artificially planting Chinese medicinal materials (CHMs) has also increased, and the ensuing pesticide residue problems have attracted more and more attention. An optimized quick, easy, cheap, effective, rugged and safe (QuEChERS) method with multi-walled carbon nanotubes as dispersive solid-phase extraction sorbents coupled with surface-enhanced Raman spectroscopy (SERS) was first proposed for the detection of deltamethrin in complex matrix Corydalis yanhusuo . Our results demonstrate that using the optimized QuEChERS method could effectively extract the analyte and reduce background interference from Corydalis . Facile synthesized gold nanoparticles with a large diameter of 75 nm had a strong SERS enhancement for deltamethrin determination. The best prediction model was established with partial least squares regression of the SERS spectra ranges of 545~573 cm -1 and 987~1011 cm -1 with a coefficient of determination ( R 2 ) of 0.9306, a detection limit of 0.484 mg/L and a residual predictive deviation of 3.046. In summary, this article provides a new rapid and effective method for the detection of pesticide residues in CHMs.

The effectiveness of carbon nanotubes (CNT) deagglomeration by rapid expansion of supercritical suspensions (RESS) in nitrogen and carbon dioxide fluids was studied in this work. Two different mechanisms of deagglomeration were proposed for these two fluids at various temperature and pressure conditions. Ultrasound attenuation spectroscopy was applied as an express method of determining median diameter and aspect ratio of CNTs. At least twofold reduction of the diameter was shown for CNT bundles processed by RESS technique. Aspect ratio of processed CNTs, calculated from acoustic attenuation spectra, increased to 340. These results were in a good agreement with atomic force microscopy data.

This study focused on preparation of calcium alginate/single-walled carbon nanotube modified by glucose (CA/SWCNT-Gl) and its application as a carrier for the drug delivery system. This bionanocomposite was synthesized by using ultrasonication as a green method. Several quantitative ratios of the SWCNTs-Gl and the alginate were applied to the assessment of formulation for the curcumin entrapment. It was optimized by employing at 1:1 the SWCNTs-Gl to calcium alginate ratio. The structure of calcium alginate/SWCNTs-Gl was characterized by FTIR, XRD, SEM, EDX, TEM, DLS and TGA techniques. The nanocomposite as a carrier was examined for measurement of entrapment efficiency, loading capacity and release study for curcumin as a hydrophobic drug. The release of curcumin from carrier-curcumin have been measured in the pH 4.5 and pH 7.5 which revealed a fast release during the first hours followed by a gradual drug release. The outcomes indicated that the nanocomposite had great potential as a carrier and enabled for drug delivery systems. Further, the carrier displayed good antibacterial activity against Bacillus cereus and Escherichia coli. Likewise, better antibacterial activity of carrier-curcumin was observed in comparison with curcumin ones., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Covalent organic frameworks (COFs) can be classified as emerging porous crystalline polymers with extremely high porosity and surface area size, and good thermal stability. These properties have awakened the interests of many areas, opening new horizons of research and applications. In the Analytical Chemistry field, COFs have found an important application in sample preparation approaches since their inherent properties clearly match, in a good number of cases, with the ideal characteristics of any extraction or clean-up sorbent. The review article is meant to provide a detailed overview of the different COFs that have been used up to now for sample preparation (i.e., solid-phase extraction in its most relevant operational modes-conventional, dispersive, magnetic/solid-phase microextraction and stir-bar sorptive extraction); the extraction devices/formats in which they have been applied; and their performances and suitability for this task.

Colon cancer is the third major cancer contributor to mortality worldwide. Nanosized particles have attracted attention due to their possible contribution towards cancer treatment and diagnosis. Photodynamic therapy (PDT) is a cancer therapeutic modality that involves a light source, a photosensitizer and reactive oxygen species. Carbon nanotubes are fascinating nanocarriers for drug delivery, cancer diagnosis and numerous potential applications due to their unique physicochemical properties. In this study, single walled carbon nanotubes (SWCNTs) were coupled with hyaluronic acid (HA) and chlorin e6 (Ce6) coated on the walls of SWCNTs. The newly synthesized nanobiocomposite was characterized using ultraviolet-visible spectroscopy, Fourier transform electron microscopy (FTIR), X-ray diffraction analysis (XRD), particle size analysis and zeta potential. The loading efficiency of the SWCNTs-HA for Ce6 was calculated. The toxicity of the nanobiocomposite was tested on colon cancer cells using PDT at a fluence of 5 J/cm 2 and 10 J/cm 2 . After 24 h, cellular changes were observed via microscopy, LDH cytotoxicity assay and cell death induction using annexin propidium iodide. The results showed that the newly synthesized nanobiocomposite enhanced the ability of PDT to be a photosensitizer carrier and induced cell death in colon cancer cells.

Flexible electronic devices with strain sensing and energy storage functions integrated simultaneously are urgently desirable to detect human motions for potential wearable applications. This paper reports the fabrication of a cotton/carbon nanotube sheath-core yarn deposited with polypyrrole (PPy) for highly multifunctional stretchable wearable electronics. The microscopic structure and morphology of the prepared sheath-core yarn were characterized by scanning electron microscopy and Fourier transform infrared spectrometry. A mechanical experiment demonstrated its excellent stretchable capacity because of its unique spring-like structure. We demonstrate that the sheath-core yarn can be used as wearable strain sensors, exhibiting an ultrahigh strain sensing range (0-350%) and excellent stability. The sheath-core yarn can be used in highly sensitive real time monitoring toward both subtle and large human motions under different conditions. Furthermore, the electrochemical performance of the sheath-core yarn was characterized by cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. The measured areal capacitance was 761.2 mF/cm 2 at the scanning rate of 1 mV/s. The method of spinning technology may lead to new exploitation of CNTs and PPy in future wearable electronic device applications.

Based on the exceptional and new opened biosensing possibilities of self-propelled micromotors, a micromotor-based immunoassay (MIm) has smartly been designed for C-reactive protein (CRP) determination in plasma of preterm infants with sepsis suspicion. The design of the micromotors involved the electrosynthesis of a carbon-based outer layer (for antibody functionalization), an intermediate Ni layer (for magnetic guidance and stopped flow operations) and PtNPs inner catalytic layer (for catalytic bubble propulsion). Micromotors biofunctionalization on the outer layer (using carbon black (CB), reduced graphene oxide (rGO) and multi-walled carbon nanotubes (MWCNTs), and biocompatible propulsion capabilities, were carefully studied. Magnetic rGO/Ni/PtNPs micromotors exhibited the most efficient and reproducible (CV = 9%) anti-CRP functionalization, controlled stopped-flow operations as well as efficient bubble propulsion (1% H 2 O 2 , 1,5% NaCh, speed 140 μm s -1 ). Analytical performance of MIm was excellent, allowing the direct (without dilution), sensitive (LOD = 0.80 μg/mL), and accurate CRP determination (E r  = 1%) in hardly available preterm babies' plasma samples with suspected sepsis using very low volumes (<10 μL) and in just 5 min of on-the-fly bioassay. Overall, the results obtained allowed the fast and reliable sepsis diagnostics in preterm babies' individuals with suspected sepsis, not only proving the usefulness of the approach as its potential utilization as point-of-care device for clinical analysis but drawing new horizons in extremely low sample volumes-based diagnostics., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

A label-free electrochemical progesterone (P4) aptasensor was successfully developed by covalently immobilizing NH 2 -functionalized P4-specific aptamer on the electrode surface. The NiO-Au hybrid nanofibers were synthesized by the electrospinning technique. GQDs-NiO-AuNFs nanocomposite was prepared by dispersing of electrospun NiO-AuNFs in the as-synthesized graphene quantum dots (GQDs) solution and stirring for 24 h. Novel GQDs-NiO-AuNFs nano-architecture in combination with functionalized multiwalled carbon nanotubes (f-MWCNTs) were further utilized to modify screen printed carbon electrode (SPCE) in order to construct an effective immobilization matrix with plenty of carboxylic functional groups. The stepwise assembly process of the designed aptasensor was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The aptamer-progesterone complex formation led to a hindered electron transfer reaction on the sensing interface, which decreased the redox probe peak current. Based on of this, progesterone could be quantitatively detected by monitoring the decrease of differential pulse voltammetric (DPV) responses of [Fe(CN) 6 ] 3-/4- peak current with increasing the progesterone concentration. Under optimized experimental parameters, the aptasensor exhibited a dynamic concentration range from 0.01 to 1000 nM and a detection limit of 1.86 pM. The proposed aptasensor was successfully employed for the determination of progesterone in human serum samples and pharmaceutical formulations., Competing Interests: Declaration of Competing Interest The authors confirm that this article content has no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The routinely used enzymes, antibodies, and nucleic acids-based biosensors for detection of Staphylococcus aureus are often overwhelmed by limited selectivity, sensitivity, high cost, and inability to discriminate between live/dead cells. This necessitates the development of an ultra-sensitive, stable, and selective electrochemical biosensor capable of discriminating live S. aureus in a mixture of live/dead cells in food samples. The current study reports the development of an electrochemical biosensor through the immobilization of bacteriophage in surface-modified bacterial cellulose (BC) matrix. BC being highly porous and fibrous, offers a high surface area for the impregnation of carboxylated multiwalled carbon nanotubes (c-MWCNTs) and allows high-density phage immobilization. Surface modification of BC/c-MWCNTs with polyethyleneimine (PEI) provides a positive charge that facilitates oriented phage immobilization. FE-SEM and FT-IR analyses confirmed the development of BC/c-MWCNTs-PEI-phage bio-interface. Confocal microscopy analysis showed 11.7 ± 1.2 phage particles⋅μm -2 immobilized in the BC matrix and showed anti-staphylococcal activity by producing clear lytic zone and reduced bacterial growth. Differential pulse voltammetry (DPV) analysis detected 3 CFU⋅mL -1 and 5 CFU⋅mL -1 of S. aureus in phosphate buffer saline (PBS) and milk, respectively, within 30 min at neutral pH and showed stability over 6-weeks at 4 °C. The biosensor showed high specificity for S. aureus, both in pure and mixed cultures of non-host bacteria, and effectively discriminated live S. aureus in a mixture of live/dead cells. The developed biosensor represents a simple, sensitive, specific, and accurate tool for early detection of S. aureus in food samples., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Bacterial biofilm is an obstacle for wound healing because it can affect the epithelialization, development of granular cells, and other regular inflammatory procedures. It plays the role of safeguarding pathogens from antiseptics and antibiotics. In this respect, this research work aims to develop heteroatom (N, F, P/B) incorporated multi-walled carbon nanotubes (MWCNT), such as NFP-MWCNT and NFB-MWCNT, which can maximize the wound healing efficacy via destroying the wound pathogen and biofilms. NFP-MWCNT and NFB-MWCNT were obtained using self-assembling ionic liquids (ILs) such as BMIM-PF 6 and BMIM-BF 4 in an acid-functionalized MWCNT (A-MWCNT) suspension, followed by pyrolysis in a nitrogen atmosphere. The composite formation was established by FTIR, XRD, RAMAN, EDX mapping, and XPS spectroscopy. TEM and SEM analyses confirmed the bamboo stick-like morphology. During this reaction, IL molecules might be cross-linked with A-MWCNT via hydrogen bonding and ionic interaction, with further pyrolysis producing the defects with doping of N, F, P, or B elements. Finally, they were assessed for their antibiofilm activity against typical bacterial strains such as K. pneumoniae, P. aeruginosa, E. coli (Gram-negative), and B. subtilis (Gram-positive), using a quantitative estimation approach. The results revealed greater effectiveness of NFB-MWCNT and NFP-MWCNT, compared to pristine MWCNT. The antibiofilm activity of NFP-MWCNT and NFB-MWCNT was associated with their specific surface chemistry (due to the presence of N, F, P/B heteroatoms), and their nanosize. Moreover, the synthesized material was examined for its wound-healing ability in Wistar rats. The results proved that cells cultured on NFB-MWCNT and NFP-MWCNT displayed exceptional healing ability. The different electronegativity between the heteroatoms creates the surface charge that inhibits the biofilm formation, leading to healing the wounds together with the heteroatom mineral source for mouse fibroblast regeneration and granulation. This is the first study in which the role of different heteroatoms incorporated into MWCNT is examined in the context of antibiofilm-associated wound-healing ability., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier B.V.)

Polylactic acid (PLA) is a biodegradable and biocompatible polyester derived from renewable resources like corn starch, presenting great potential in clinical applications like tissue engineering, implants and drug delivery systems. However, the intrinsic brittleness restricts its real applications. In this work, PLA nanocomposites were prepared by incorporating a small amount of carboxyl functionalized multi-walled carbon nanotubes (CNTs) and surface compatabilized montmorillonite (MMT) via technologies of freeze-drying and masterbatch-based melt blending. In the resulting nanocomposites, a well-distributed nano-filler network with microstructures of 1-D CNTs/2-D MMT platelets is formed favored by the enhanced interfacial interaction between the organic modified fillers with PLA matrix. Thanks to the well dispersed organic modified nanofillers, a large number of microcracks and extremely stretched PLA matrix are induced during tensile process, dissipating amounts of energy. As a result, the filler networks reinforce PLA with increment of 19% in modulus, remarkably increase by 13.8 times in toughness relative to PLA control without sacrificing strength. Thus, the PLA nanocomposites with excellent properties prepared through the facile and effective route possess broad prospect in biomedical applications., (Copyright © 2020. Published by Elsevier B.V.)

Herein we propose cellulose acetate/carbon nanotube/silver nanoparticles (CA/CNT/Ag) nanofiber composite for antibacterial applications. The nanofiber composite are expected to avoid harmful effects of silver (i.e. argyria and argyrosis) owing to anchoring of silver nanoparticles on carbon nanotubes (CNTs) and embedding of the composite inside cellulose acetate (CA) matrix. The carbon nanotubes/silver nanoparticles (CNT/Ag) nanocomposite localized inside the CA polymer matrix allow minimal/no direct contact of silver nanoparticles with human cells and are expected to show reduced silver leaching. The cellulose acetate (CA) nanofibers loaded with silver nanoparticles anchored multiwall carbon nanotubes (CNT/Ag) were fabricated by electrospinning. The samples were studied with scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), Fourier transform infra-red spectroscopy (FTIR), tensile strength tests and antibacterial assays. Synthesis of the CNT/Ag nanocomposite was confirmed with XPS, XRD, EDS and TEM analysis. SEM images showed regular morphology of the CA/CNT/Ag nanofiber composites. TEM images depicted anchoring of silver nanoparticles on CNTs and embedding of CNT/Ag in the CA nanofiber matrix. The antibacterial test results demonstrated excellent antibacterial performance of the CA/CNT/Ag. The CA/CNT/Ag samples ensured effective bacterial growth inhibition on agar plates, in liquid medium (optical density, OD 590nm ) (for 48 h) and in bactericidal assay (relative cell viability, %). Our results suggested CA/CNT/Ag composite nanofibers as potential candidate for safer antibacterial applications., Competing Interests: Declaration of competing interest None., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Aim: This study determined the optimum gamma irradiation dosage to sterilize sodium hyaluronate (HY), single-walled carbon nanotubes (SWCNT), multi-walled carbon nanotubes (MWCNT) and CNT functionalized with HY (HY-SWCNT and HY-MWCNT), evaluated the structural integrity of the materials and assessed whether sterilized materials kept biological properties without affecting renal function., Main Methods: Materials were submitted to dosages of 100 gγ to 30 Kgγ and plated onto agar mediums for colony forming units (CFUs) counting. Sterilized samples were inoculated with 10 7 Bacillus clausii, submitted again to gamma irradiation, and plated in agar mediums for CFUs counting. Scanning electron microscope was used for structural evaluation of sterilized materials. Tooth sockets of rats were treated with sterilized materials for bone formation assessment and renal function of the animals was analyzed., Key Findings: The optimum gamma dosage for sterilization was 250 gγ for HY and 2.5 Kgγ for the other materials without meaningful structural changes. Sterilized materials significantly increased bone formation (p < 0.05) and they did not compromise renal function and structure., Significance: Gamma irradiation efficiently sterilized HY, SWCNT, MWCNT, HY-SWCNT and HY-MWCNT without affecting structural aspects while maintaining their desirable biological properties., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2020 Elsevier Inc. All rights reserved.)

This work is devoted to the study of phase transition processes in nanostructured ceramics of the Y 2 O 3 /TiO 2 -Y 2 TiO 5 type doped with carbon nanotubes as a result of thermal annealing, as well as to the assessment of the prospects of the effect of phase composition on photocatalytic activity. By the method of X-ray phase analysis, it was found that an increase in the annealing temperature leads to the formation of the orthorhombic phase Y 2 TiO 5 , as well as structural ordering. Based on the obtained UV spectra, the band gap was calculated, which varies from 2.9 eV (initial sample) to 2.1 eV (annealed at a temperature of 1000 °C). During photocatalytic tests, it was established that the synthesized nanostructured ceramics Y 2 O 3 /TiO 2 -Y 2 TiO 5 doped CNTs show a fairly good photocatalytic activity in the range of 60-90% decomposition of methyl orange.

Dopamine homeostasis is an important clinical diagnostic index, because an abnormal level in the human body is closely related to certain serious diseases. Herein, a novel electrochemical sensing platform based on gold nanobipyramid/multi-walled carbon nanotube hybrids (AuNBP/MWCNTs) is developed to detect dopamine in human fluids. Using field emission scanning electron microscopy, it is observed that AuNBPs of about 60 nm with two pyramids are well dispersed on the surface of MWCNTs. Energy-dispersive X-ray spectrometry, X-ray diffraction and X-ray photoelectron spectroscopy confirm that AuNBPs are self-assembled onto the surface of MWCNTs to form the hybrids. Cyclic voltammetry reveals that the AuNBP/MWCNTs exhibit good electrocatalytic activity toward dopamine oxidation owing to the synergistic effects of AuNBPs and MWCNTs. In addition, both cyclic voltammetry and differential pulse voltammetry display three well-resolved and distinct oxidation peaks on the AuNBP/MWCNT-modified glassy carbon electrode. Based on AuNBP/MWCNTs, the newly developed electrochemical sensor is used to detect dopamine in the presence of ascorbic acid and uric acid over a wide linear range from 50 nM to 2.7 mM and a low detection limit of 15 nM (at S/N = 3). The electrochemical sensor can also be applied for the quantitative analysis of dopamine in real samples. Graphical abstract A novel electrochemical sensing platform based on gold nanobipyramid/multi-walled carbon nanotube hybrids (AuNBP/MWCNTs) was proposed to detect dopamine in the presence of ascorbic acid and uric acid.

Currently, there is a lack of ultrasensitive diagnostic tool to detect some diseases such as ischemic stroke, thereby impacting effective and efficient intervention for such diseases at an embryonic stage. In addition to the lack of proper detection of the neurological diseases, there is also a challenge in the treatment of these diseases. Carbon nanotubes have a potential to be employed in solving the theragnostic challenges in those diseases. In this study, carbon nanotubes were successfully synthesized for potential application in the detection and treatment of the neurological diseases such as ischemic stroke. Vertically aligned multiwalled carbon nanotubes (VA-MWCNTs) were purified with HCl, carboxylated with H 2 SO 4 :HNO 3 (3:1) and acylated with SOCl 2 for use in potential targeting studies and for the design of a carbon-based electrode for possible application in the diagnosis of neurological diseases, including ischemic stroke. MWCNTs were washed, extracted from the filter membranes and dried in a vacuum oven at 60 °C for 24 h prior to functionalization and PEGylation. CNTs were characterized by SEM, TEM, OCA, DLS, CV and EIS. The HCl-treated CNT obtained showed an internal diameter, outer diameter and thickness of 8 nm, 34 nm and 75 µm, while these parameters for the H 2 SO 4 -HNO 3 -treated CNT were 8 nm, 23 nm and 41µm, respectively. PEGylated CNT demonstrated zeta potential, polydispersive index and particle size distribution of 6 mV, 0.41 and 98 nm, respectively. VA-MWCNTs from quartz tube were successfully purified, carboxylated, acylated and PEGylated for potential functionalization for use in targeting studies. For designing the carbon-based electrode, VA-MWCNTs on silicon wafer were successfully incorporated into epoxy resin for diagnostic applications. Functionalized MWCNTs were nontoxic towards PC-12 neuronal cells. In conclusion, vertically super-aligned MWCNTs have been successfully synthesized and functionalized for possible theragnostic biomedical applications in neurological disorders such as ischemic stroke., Competing Interests: The authors declare no conflicts of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript and in the decision to publish the results.

Compared to transmission systems based on shafts and gears, tendon-driven systems offer a simpler and more dexterous way to transmit actuation force in robotic hands. However, current tendon fibers have low toughness and suffer from large friction, limiting the further development of tendon-driven robotic hands. Here, we report a super tough electro-tendon based on spider silk which has a toughness of 420 MJ/m 3 and conductivity of 1,077 S/cm. The electro-tendon, mechanically toughened by single-wall carbon nanotubes (SWCNTs) and electrically enhanced by PEDOT:PSS, can withstand more than 40,000 bending-stretching cycles without changes in conductivity. Because the electro-tendon can simultaneously transmit signals and force from the sensing and actuating systems, we use it to replace the single functional tendon in humanoid robotic hand to perform grasping functions without additional wiring and circuit components. This material is expected to pave the way for the development of robots and various applications in advanced manufacturing and engineering.

Functionalized multi-walled carbon nanotubes have been extensively gained popularity in pancreatic cancer gene therapy. LyP-1, a peptide, has been proved to specifically bind pancreatic cancer cells. The potential therapeutic effect of LyP-1-conjugated functionalized multi-walled carbon nanotubes in treating pancreatic cancer is still unknown. In this study, LyP-1-conjugated functionalized multi-walled carbon nanotubes were successfully synthesized, characterized and showed satisfactory size distribution and zeta potential. Compared with functionalized multi-walled carbon nanotubes, cellular uptake of LyP-1-functionalized multi-walled carbon nanotubes was shown to be increased. Compound of LyP-1-functionalized multi-walled carbon nanotubes and MBD1siRNA showed superior gene transfection efficiency. Moreover, LyP-1-fMWNTs/MBD1siRNA complex could significantly decrease the viability and proliferation and promoted apoptosis of pancreatic cancer cells in vitro. Further xenograft assays revealed that the tumour burden in the nude mice injected with LyP-1-functionalized multi-walled carbon nanotubes/MBD1siRNA was significantly relieved. The study demonstrated that LyP-1-functionalized multi-walled carbon nanotubes/MBD1siRNA could be a promising candidate for tumour active targeting therapy in pancreatic cancer., (© 2020 The Authors. Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.)