Doped Carbon Nanotubes Research Articles

Acoustic emission based experimental study on mechanical properties and damage analysis of carbon nanotube reinforced fiber shotcrete

Fiber shotcrete support is an important method for initial support in tunneling, slope, and foundation pit projects. However, the strength of fiber shotcrete is affected by the substantial number of irregularly dispersed pores and microcracks due to the constraints of the spraying process, surrounding rock conditions, and construction environment. Therefore, to improve the mechanical properties of fiber shotcrete, this paper proposes the addition of carbon nanotubes (CNTs) to mixed alkali-resistant glass fiber-reinforced shotcrete (AR-GFRS). Mechanical experiments were used to examine the impact of CNT admixture and curing time on the strength of AR-GFRS. The acoustic emission (AE) properties and damage patterns of CNT glass fiber shotcrete (CNGC) specimens were examined using the AE monitoring technique. Scanning electron microscopy, or SEM, was used to analyze the specimens' microscopic characteristics. Research shows: (1) At 0.2 wt% CNT doping, the compressive strength and the split tensile strength of CNGC specimens were enhanced to peak values. (2) An increment in the ratio of CNT to the overall mass led to an increase and then a decrease in the values of the CNGC intensity and AE characterization parameters. (3) Combined with the RA-AF analysis, CNGC specimens showed more than 80 % of shear damage, so CNGC damage mode was more stable shear damage. (4) It was found by SEM that the incorporation of CNT promoted the production of hydration products and enhanced the homogeneity of the specimens. The results of this study add innovative ideas and references for the use of CNT-reinforced fiber shotcrete.

Potassium doping of vertically aligned multi-walled carbon nanotubes.

Alkali metal doping of multi-walled carbon nanotubes is of great interest, both fundamentally to explore the effect of dopants on quasi-one-dimensional electrical systems and for energy applications such as alkali metal storage. We present an investigation with complementary photoemission and Raman spectroscopies, fully carried out in an ultra-high vacuum, to unveil the electronic and vibrational response of a forest of highly aligned multi-walled carbon nanotubes by in situ potassium doping. The charge donation by the alkali adatoms induces a plasmon mode, and the density of states undergoes an energy shift consistent with electron donation and band filling of the multi-walled carbon nanotube band structure. The π-states in the valence band and the Raman peaks unveil an evolution that can be ascribed to charge donation and partially to a tensile strain exerted by the K adatoms on the carbon lattice. All these effects are thermally reversible, fostering these materials as a potential system for electronic charge harvesting.

Novel ratiometric electrochemical aptasensor based on broad-spectrum aptamer recognition for simultaneous detection of penicillin antibiotics in milk

To effectively monitor multi-residues of penicillin antibiotics (PENs) in milk, we developed a novel ratiometric electrochemical aptasensor enabling simultaneous detection of PENs. The aptasensor employed a broad-spectrum aptamer as a recognition element, niobium carbide functionalized with methylene blue (Nb2C-MB) as a reference signal generator, and a ferrocene-labeled aptamer (Fc-Apt) as an output signal. Electrodes were modified with Fe-N-C doped carbon nanotubes (Fe-N-C-CNTs) to amplify detection signals further. During detection, Fc-Apt binding to PENs decreased Fc current intensity (IFc) and increased MB current intensity (IMB). The simultaneous detection of PENs was achieved using IMB/IFc as a quantitative signal. Under optimal conditions, a good linear relationship between IMB/IFc and antibiotic concentration was observed, indicating the aptasensor had a robustness. The limits of detection of aptasensor for four penicillin antibiotics and their mixed targets were 0.093–0.191 nM. This work provides a new approach to multi-residue detection of the same class of antibiotics.

Adsorption and separation of lead ions in phosphoric acid by co-doped carbon nanotubes with sulfur, oxygen, and manganese

The purpose of this study was to prepare a novel and efficient adsorbent for the removal of trace Pb(II) from phosphoric acid. Manganese oxide/sulfur-oxygen doped carbon nanotube composites (CNTs-S-O-Mn) were prepared from multi-walled carbon nanotubes modified with nitric acid, mercaptoacetic acid, acetic anhydride, concentrated sulfuric acid and potassium permanganate. Characterisation revealed that CNTs-S-O-Mn contained hydroxyl, sulphonate groups, MnO and Mn3O4. At 298 K, 15.362 mg·L-1 initial concentration of lead ions, and 18.4 % phosphoric acid concentration, the adsorption capacity of the composites for lead ions was 38.65 mg·g−1, which was higher than that of the unmodified CNTs, 8.04 mg·g−1. The adsorption kinetic data at 298 K conformed to the quasi-second-order kinetic equation, R2 = 0.997; 298, adsorption isotherms at 308 and 318 K conformed to the Langmuir equation, R2 = 0.990–––0.991. The adsorption capacity increased with decreasing phosphoric acid concentration. In this system, the adsorption is affected by a certain concentration of lead ions. Adsorption occurs via chemisorption and is exothermic. Sulfonic acid groups and hydroxyl groups on manganese oxides play an important role in the adsorption of Pb (II) through surface complexation with Pb (II). These results indicate that the removal of trace Pb (II) from phosphoric acid by modified carbon nanotubes is feasible, revealing a new use of carbon nanotubes for phosphoric acid purification.

Alleviating Ni electron depletion of Ni phthalocyanine by doping electron-deficient boron in CNTs support for enhanced CO2 electroreduction

Dispersed nickel phthalocyanine (NiPc) on carbon nanotubes (CNTs) is the promising electrocatalyst for carbon dioxide reduction (CO2RR), but the strong interfacial electron interaction causes Ni electron depletion, limiting CO2RR performance. Herein, engineering the heteroatom doping in CNTs is proposed to alleviate electron depletion of Ni sites toward effective CO2RR. Boron heteroatoms induce electron-enriched Ni sites in NiPc/B-CNTs compared to phosphorus, nitrogen, and fluorine doped catalysts, resulting in superior CO2RR performance. Impressively, the NiPc/B-CNTs presents high CO Faraday efficiency (FECO) of >98 % from −20 to −80 mA cm−2 and excellent stability up to 37 h with sustained FECO of > 90 % in neutral electrolyte. Theoretical and experimental investigation reveals that implanting B heteroatoms alleviates Ni electron depletion via weakening electron transfer from NiPc to CNTs and thus reduces reaction barrier of *COOH formation, facilitating CO2RR. This study highlights importance of modifying carbon substrate in development of supported molecular catalysts for practical applications.

Evaluation of absorption behavior of Streptozocin anti-cancer drug on Cr doped Carbon Nanotube (5,5) using DFT theoretical method

In this study, the physicochemical characteristics of the adsorption of the anticancer drug Streptozocin (STZ, Zanosar) on the extern surface of Cr-doped carbon nanotube (CNTCr) have been investigated. Optimization all structures were performed using the DFT method at the mpw1pw91/6-311G level of theory. The energies, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), the density of states (DOS), the distribution of electric charges, and the dipole moments have been calculated to investigate the physical chemistry behaviors of the structures. As well as, the molecular descriptors such as electrophilicity (ω), chemical potential (μ), chemical hardness (h) and chemical softness (S) of compounds were investigated. Examination of the intramolecular and intermolecular bonds indicates that the adsorption of the drug on the nanotube surface has been taking place. Also, the calculated adsorption energy was negative and indicates that the adsorption is thermodynamically possible. All the obtained results of the theoretical calculations have shown that CNTCr is suitable for delivering the anti-cancer drug STZ.

Selective chemical doping of carbon nanotube conductors to reduce contact resistance with copper in ultrasonic welds

Electrochemical devices such as batteries, fuel cells, and capacitors employing a carbon nanotube (CNT) electrode can be improved by lowering the contact resistance between CNTs and metallic contacts. The current work investigates two simultaneous strategies to enhance the contact by using chemical doping of CNTs with potassium tetrabromoaurate (KAuBr4) and ultrasonic welding to a metal foil. The specific contact resistivity was measured using the transfer length method (TLM) to evaluate CNT test structures having ultrasonically welded Cu contacts with and without KAuBr4 doping. Purified CNT-Cu samples had a specific contact resistivity of 5.4 mΩ cm2, whereas the KAuBr4 doped CNT-Cu samples were 2.2 mΩ cm2. Confirmation of selective doping to the weld region was made using measured differences in the emissivity of purified and KAuBr4 doped CNTs, which were 0.84 and 0.56, respectively. The lower contact resistance from KAuBr4 doped CNT-Cu ultrasonic welds also reduced the extent of Joule heating beyond the contact region when applying increasing current to failure in a 2-terminal test structure. The benefit of selectively doped CNT-Cu welds was demonstrated across rectangular ribbon and electrode form factors up to an area of 6 cm × 8 cm (typical of electrochemical pouch-cell current collectors). Each form factor showed a 1.5× reduction in peak temperature when selective doping of the CNTs was performed prior to ultrasonic welding of the Cu contact. Thus, the combination of selective doping and ultrasonic welding demonstrates a viable method to fabricate low electrical resistance between CNT electrodes and metallic contacts for electrochemical devices.

Photoinduced Dynamics of a Single-Walled Carbon Nanotube with a sp3 Defect: The Importance of Excitonic Effects.

Herein, we employed linear-response time-dependent functional theory nonadiabatic dynamic simulations to explore the photoinduced exciton dynamics of a chiral single-walled carbon nanotube CNT(6,5) covalently doped with a 4-nitrobenzyl group (CNT65-NO2). The results indicate that the introduction of a sp3 defect leads to the splitting of the degenerate VBM/VBM-1 and CBM/CBM+1 states. Both the VBM upshift and the CBM downshift are responsible for the experimentally observed redshifted E11* trapping state. The simulations reveal that the photoinduced exciton relaxation dynamics completes within 500 fs, which is consistent with the experimental work. On the other hand, we also conducted the nonadiabatic carrier (electron and hole) dynamic simulations, which completely ignore the excitonic effects. The comparison demonstrates that excitonic effects are indispensable. Deep analyses show that such effects induce several dark states, which play an important role in regulating the photoinduced dynamics of CNT65-NO2. The present work demonstrates the importance of including excitonic effects in simulating photoinduced processes of carbon nanotubes. In addition, it not only rationalizes previous experiments but also provides valuable insights that will help in the future rational design of novel covalently doped carbon nanotubes with superior photoluminescent properties.

Application of a novel deep eutectic solvent modified carbon nanotube for pipette-tip micro solid phase extraction of 6-mercaptopurine

Background6-mercaptopurine (6-MP) is a chemotherapy drug mainly used to treat leukemia. It is a persistent organic pollutant and can remain in the environment for a long period of time. The presence of 6-MP in the environment poses a number of hazards and needs to be assessed to monitor its potential risk to human health and the environment. However, due to its trace amount in complicated matrices, a clean-up and preconcentration step before its determination is compulsory.ResultsAs a highly efficient adsorbent for the extrication of 6-mercaptopurine (6-MP), a novel carbon nanotube doped with camphor: decanoic acid deep eutectic solvent was synthesized and applied as a packing material for the pipette-tip micro solid phase extraction sorbent of 6-MP from tap, wastewater and seawater samples before its spectrophotometric determination. Characteristics and structure of this adsorbent was fully investigated. Factors affecting extraction, including type and volume of the eluent, ionic strength and pH of the sample solution, amount of adsorbent, and number of extraction and elution cycles were optimized using one-factor-at-a-time and response surface methodologies. The method was found to be linear in the range of 1 to 1000 µg/L with a limit of detection and quantification of 0.2 and 0.7 µg/L, respectively. Reproducibility as relative standard deviation was better than 4.6%.ConclusionApplication of deep eutectic solvent modified carbon nanotube indicated suitable microextraction results and good potential for rapid extraction of trace amounts of 6-MP from different aqueous samples. The amount of sample required for the analysis was less than 10 mL and only 1.5 mg of the adsorbent was used. The total analysis time, including extraction was less than 15 min and the adsorbent could be used for at least 10 times, without significantly losing its adsorption ability. Compared to using unmodified usual carbon nanotubes, deep eutectic solvent doped carbon nanotubes showed 19.8% higher extraction ability.

A comprehensive approach for doping selection and assessment in porous materials for hydrogen storage: CNTs study case

Identifying a nanostructure suitable for hydrogen storage presents a promising avenue for the secure and cost-effective utilization of hydrogen as a green energy source. This study introduces a systematic approach for selecting optimal doping on porous materials, emphasizing the intricate interplay between doping with the material's structure and the interaction between doping and hydrogen. Our proposed approach serves as a framework for evaluating and predicting the performance of doped materials. To validate the efficacy of our strategy, we conduct a comprehensive investigation in carbon nanotubes (CNTs). Applying our criteria, we systematically screen several dopants in CNTs. The results highlight Cu-doped CNTs as promising candidates for hydrogen storage applications. Focusing on Cu-doped CNTs, we analyze binding energy, charge transfer, partial density of states (PDOS), and desorption temperature to assess the performance of modified CNTs. Additionally, we explore the feasibility of doped CNTs featuring various sizes of copper clusters and the effect on the release temperature, i.e., complete regeneration. The findings indicate that incorporating 5 to 6% copper impurity onto CNT surfaces renders these nanostructures highly applicable for reversible hydrogen storage near ambient conditions.

Enhancing piezoelectric performance of CNTs through B and N substitution under combined mechanical loads: insights from MD simulations

The piezoelectric properties of carbon nanotubes (CNTs) doped with boron (B) and nitrogen (N) were studied using the classical molecular dynamics (MD) simulation software package large scale atomic/molecular massively parallel simulator. The interactions among the nanotube atoms C, N, and B were calculated using the Tersoff potential. MD simulations were performed to observe the changes in the piezoelectric coefficient of the doped CNTs under loading conditions like tension, torsion, and a combination of both. We considered a wide range of chirality to determine the influence of structural variation on the piezoelectric effect. The study revealed that B-CNTs exhibit superior piezoelectric coefficients compared to N-CNTs, indicating the significant role of dopant type. Moreover, under tensile loading, zigzag-oriented B-CNTs showed higher piezoelectric coefficients with a maximum e33 = 0.2441 C m−2, whereas under torsional loading, armchair-oriented B-CNTs showed enhanced response with a maximum e36 = 0.0564 C m−2. A notable observation was that under combined loading conditions (tensile and torsional), the piezoelectric behavior of the B-CNTs was dependent on the nanotube’s chirality and did not yield a linear additive response. The polarization induced under combined loading in most of the doped CNTs is significantly higher than the sum of polarization generated under tensile and torsional loading conditions. This behavior suggests that the overall piezoelectric effect under combined loading can be enhanced, which emphasizes the need for an approach to optimize the mechanical loading condition. The results showcase the potential of B-/N-CNTs to be engineered for efficient performance by demonstrating that tailored mechanical loading can enhance the piezoelectric responses in doped CNTs, opening a pathway for highly functional and efficient nanoscale piezoelectric devices.

Dimetallic praseodymium-cobalt carbon nanotubes as highly efficient electrocatalyst for oxygen reduction reaction

In this study, six bimetallic rare earth (RE = La, Ce, Pr, Nd, Sm, Eu) cobalt nitrogen doped carbon nanotubes (RECo-NCNTs) were synthesized with g-C3N4 derivative method. These RECo-NCNTs were characterized by SEM, BET, XPS, XRD and Raman. In addition, their catalytic performances for oxygen reduction reaction (ORR) had also been tested. The introduction of rare earths did not destroy the structure of nanotubes but apparently change their ORR performances. The PrCo-NCNTs showed the significant improvement in catalytic ability for ORR (onset potential of 0.95 V and half-wave potential of 0.79 V), which is very close to that of commercial 20 % Pt/C. Moreover, PrCo-NCNTs exhibits an excellent catalytic stability (no activity decay after 10000st cycles) and an outstanding methanol toxic tolerance. Assembled in metal–air batteries (Zn-air, Al-air and Mg-air), the PrCo-NCNTs electrode also presents high power densities and discharge voltages.

High-temperature adsorption of nitrogen dioxide for stable, efficient, and scalable doping of carbon nanotubes

This work is devoted to a novel efficient strategy for single-walled carbon nanotube doping employing heat treatment with nitrogen dioxide (NO2). Unlike numerous reports of unstable NO2 doping at room temperature, our method combines high efficiency and stability, enabled by its temperature-dependent adsorption on the nanotube surface. We reveal that doping stability increases with the treatment temperature reaching maxima at 300 °C avoiding any detrimental effect on nanotube structure and optical transmittance. As a result, we demonstrate doped carbon nanotube transparent conductive films exhibiting competitive performance (in respect to films treated with other dopants) with a less than 50% drop in conductive characteristics for over a year. Thermo-programmed desorption analysis and X-ray photoelectron spectroscopy confirm the preferential formation of long-living adsorbed nitrogen species, such as NO3-groups, as a result of high-temperature treatment. We believe the current work provides a basis for the robust and technologically efficient doping of single-walled carbon nanotubes and related structures at industrial scales, as the developed method could be easily coupled with a continuous technology of carbon nano materials production.

Optimization of Carbon Nanotube Doped Glass Fiber Reinforced Composite Material Using Taguchi Based Critic-CoCoSo Method

Bu makale, çok duvarlı karbon nanotüp (ÇDKNT) ile takviye edilmiş cam elyaf takviyeli polimer (CETP) kompozitlerin işleme verimliliğini, Taguchi ve Critic-CoCoso yöntemiyle değerlendirmesini sunmaktadır. Çalışmada delik delme işlemlerinde, farklı oranlarda çok duvarlı karbon nano tüp katkılı CETP malzemelerin, farklı takım tipiyle, işleme parametrelerinin, yüzey pürüzlülüğü, delaminasyon ve itme kuvveti üzerindeki etkileri araştırılmıştır. Deneyler Taguchi L27 ortogonal dizilimine göre planlanarak her bir kontrol parametresinin çıktılar üzerindeki etkileri S/N oranı yöntemiyle belirlenmiştir. 
 Yapılan çalışmada, CETP matrix composite materials ın işlenmesinde kullanılan parametrelerin optimum değerlerinin belirlenmesi amaçlanmıştır. Elde edilen çıktı sayısının birden fazla olması, farklı ve çelişkili cevap değerlerinin birbirleri üzerindeki etkilerinin de dikkate alınmasını gerektirmektedir. Bu sebeple bütün çıktıların tek bir amaç fonksiyonu olarak değerlendirilebilmesi için uygulamada sıklıkla kullanılan çok kriterli karar verme yöntemleri (ÇKKV) kullanılmaktadır. Önce tüm çıktı değerlerinin minimizasyonunu sağlamak için veriler Critic yöntemiyle ağırlıklandırılmış daha sonra da, çok kriterli karar verme yöntemlerinden CoCoSo yöntemi kullanılarak karşılaştırmalı analizi yapılmıştır.

Enhancing Liquid Crystal Properties through Nanoparticle Doping: A Mini Review

Liquid crystals doped with nanoscale particles have recently acquired popularity, improving their capabilities and applications. The impact of doping metallic and metal-oxide nanoparticles as well as other nanoparticles in liquid crystals is presented in this brief review. Silver nanoparticles (Ag NPs) have an effect on phase transitions, molecular alignment and electrical properties such as threshold voltage and response time. The optical tilt and electro-optical characteristics of gold nanoparticles (Au NPs) are improved. Metal-oxide nanoparticles such as MgO, ZnO, Al2O3, CuO and SiO2 enhance dielectric properties, mitigate screening effects, increase birefringence, and reduce light leakage. Doping carbon nanotubes (CNTs) influences impedance, optical transmittance and electro-optical properties. The review aims to study the effects of nanoparticle doping on liquid crystal features such as phase transitions, molecular alignment, electrical and optical properties, dielectric behavior, and impedance. A better understanding of these modifications can lead to more applications for liquid crystal in areas such as sensors, displays, optoelectronics, and photovoltaics.

Complex chemistry of carbon nanotubes toward efficient and stable p-type doping

Developing efficient and stable carbon nanotube (CNT) doping techniques and elucidating their chemistry is essential for their further implementation in electronic and energy devices. Here, protonic acids and lithium salts are employed as p-type inducers and stabilizers of the doped state, respectively. Leveraging the electron-withdrawing capability of protons, protonic acids can easily induce heavily p-doped states in CNTs. Anionic species from the acids attach to the positively charged CNTs to achieve charge compensation. Introducing lithium salts with bulky, charge-delocalized anions to the p-doped CNTs results in an anion replacement driven by the free energy gain. The newly formed complexes demonstrate outstanding thermal stability in air, enduring a temperature of 100 °C for over a year. The chemical hardness of the applied anion effectively explains the difference in stability of the doped CNTs, indicating that the doping process and its stabilization can be understood and controlled through complex chemistry.

Study on the adsorption of 2,4-dichlorophenoxyacetic acid on silver doped carbon nanotube using tight-binding quantum chemical method

The GFN2-xTB tight-binding quantum chemical method was utilized to investigate the adsorption ability of 2,4-dichlorophenoxylacetic acid (2,4-D) on pristine single-walled carbon nanotube (CNT) and silver-doped carbon nanotube (Ag-CNT). The effects of solvents (water, methanol, and acetonitrile) on the adsorption process were evaluated via the linear Poisson-Boltzmann analysis algorithm. The analysis of ionization energy, electron affinity, and global electrophilic indexes indicates that Ag doping alters the electronic properties of CNT through the formation of Ag-C chemical bonds. While the adsorption process of 2,4-D on pristine CNT is primarily of a physical nature, the adsorption on Ag-CNT involves chemical adsorption facilitated by the formation of Ag-Cl and Ag-O bonds. Contributions from non-covalent interactions (such as π-π stacking, van der Waals interactions, etc.) were analysed and clarified through the computation of the reduced density gradient. Our findings suggest that Ag-CNT has significant potential as a material for the adsorption and remediation of 2,4-D.

A microelectrode electrochemical sensing platform based on heteroatoms doped carbon nanotubes arrays with peroxidase-like activity for in-situ detection in live cell

In this work, we developed a new strategy to fabricate a series of transition metallic nanoparticles (NPs) embedded on B, N co-doped carbon nanotubes (CNTs) arrays modified flexible carbon fiber electrodes (M@BNCNTs/CF, M = Co, Fe, Ni) via facile inkjet printing assisted with chemical vapor deposition using Ionic liquid as solvent of printing ink and heteroatom dopants. Furthermore, Pt NPs via impregnation-thermal reduction process was anchored on the surface of Co@BNCNTs/CF (Pt–Co@BNCNTs/CF), which holds enhanced peroxidase-like activity and could be directly used as freestanding electrode to detect H2O2, exhibiting a low detection limit of 0.19 μM with wide linear range (0.5 μM–9.4 mM), and high sensitivity (1679 μA cm−2 mM−1). The excellent sensing performance of Pt–Co@BNCNTs/CF is attributed to the Pt, Co NPs anchored on CNTs with great catalytic activity, and the doping B, N would cause graphitic carbon with more defects to improve its inherent reactivity toward H2O2. Besides, CNTs arrays with high surface area also enlarge the exposure of active sites. Moreover, the Pt–Co@NBCNTs/CF microelectrode has been successfully applied in monitoring H2O2 secreted from human colonic cancer cells and normal colonic epithelial cells, which could offer crucial data for distinguishing various cell types and identifying cancer cells from normal cells. This work opens a new horizon to fabricate flexible miniaturized sensing device for extracellular analysis and offers an extended strategy to fabricate other metallic NPs embedded in heteroatoms doped CNTs functionalized flexible fiber electrode, by choosing diverse metal ions and ILs as inkjet printing precursors.

Effective synthesis of nitrogen doped carbon nanotubes over transition metal loaded mesoporous catalysts for energy storage of supercapacitor applications

Abstract In the present work, the nitrogen doped carbon nanotubes (NCNTs) were prepared over various transition metal loaded mesoporous SBA-15 catalysts by the CVD method for supercapacitor application. Mesoporous Siliceous SBA-15 support and transition metals (Cr, Fe, Co, Ni and Cu) loaded SBA-15 (M/SBA-15) catalysts were prepared through hydrothermal and wet impregnation process, respectively. The catalytic performance of all the prepared catalysts were evaluated by synthesizing NCNTs by CVD at 800 °C using triethylamine as the precursor. The NCNTs produced over Ni/SBA-15 have an outstanding specific capacitance of 263 F g−1 at 0.5 A g−1 in 1.0 M H2SO4 aqueous solution according to the electrochemical investigations because of its increased nitrogen content of 3.2 at.%. Furthermore, a two-electrode based symmetric device was construct and tested. The fabricated device showed the specific capacitance of 113 F g−1 at 0.5 A g−1 with high energy density of 10 W h Kg−1 at the power density of 333 W kg−1. The NCNT showed 96 % of capacitance retention even after 1000 cycles. The synergism of high nitrogen content and bamboo-like graphitized structure resulted in excellent specific capacitance, better cycle life and rate performance of the prepared NCNTs as supercapacitor electrode.

Effect of Surface Chemistry on Hemolysis, Thrombogenicity, and Toxicity of Carbon Nanotube Doped Thermally Sprayed Hydroxyapatite Implants.

Assessing blood compatibility is crucial before in vivo procedures and is considered more reliable than many in vitro tests. This study examines the physiochemical properties and blood compatibility of bioactive powders ((0.5-2 wt % carbon nanotube (CNT)/alumina)-20 wt %)) produced through a heterocoagulation colloidal technique followed by ball milling with hydroxyapatite (HAp). The 1 wt % CNT composite demonstrated a surface charge ∼5 times higher than HAp at pH 7.4, with a value of -11 mV compared to -2 mV. This increase in electrostatic charge is desirable for achieving hemocompatibility, as evidenced by a range of blood compatibility assessments, including hemolysis, blood clotting, platelet adhesion, platelet activation, and coagulation assays (prothrombin time (PT) and activated partial thrombin time (aPTT)). The 1 wt % CNT composite exhibited hemolysis ranging from 2 to 7%, indicating its hemocompatibility. In the blood clot investigation, the absorbance values for 1-2 wt % CNT samples were 0.927 ± 0.038 and 1.184 ± 0.128, respectively, indicating their nonthrombogenicity. Additionally, the percentage of platelet adhered on the 1 wt % CNT sample (∼5.67%) showed a ∼2.5-fold decrement compared to the clinically used negative control, polypropylene (∼13.73%). The PT and aPTT experiments showed no difference in the coagulation time for CNT samples even at higher concentrations, unlike HAC2 (80 mg). In conclusion, the 1 wt % CNT sample was nontoxic to human blood, making it more hemocompatible, nonhemolytic, and nonthrombogenic than other samples. This reliable study reduces the need for additional in vitro and in vivo studies before clinical trials, saving time and cost.