Addition Of Multi-walled Carbon Nanotubes Research Articles

Advanced anaerobic digestion by co-immobilization of anaerobic microbes and conductive particles in hydrogel for enhanced methane production performance

Recent research has increasingly focused on the enhancement of anaerobic digestion (AD) through direct interspecies electron transfer (DIET) facilitated by conductive particles (CP). Although this approach can significantly accelerate the AD process, the contact efficiency between CPs and AD microbes is relatively low due to the flow of water in a dispersed condition, leading to possible DIET inefficiency. In this study, a unique approach involving the “co-immobilization” of anaerobic microbes and multi-walled carbon nanotubes (MWCNTs) as CP into a hydrogel matrix was developed to improve the AD process. The advantages of this method include improved contact efficiency between microbes and CPs for enhanced DIET, and increased CP retention within the reactor, thereby omitting the need to compensate for CP washout. The methane production rate for the co-immobilized hydrogel was 2.5-fold and 1.9-fold faster than that of the control (dispersed sludge) and conventional DIET (dispersed sludge with MWCNT addition), respectively. Microbial analysis indicated the enrichment of functional microbes such as Anaerolineacea, Sedimentibacteraceae, Rhodocyclaceae, and Methanothrichaceae, which could be involved in the DIET under co-immobilized conditions. These results demonstrate the potential of the proposed method for realizing an advanced continuous AD process through improved DIET.

On the Effect of Fibre Orientation and MWCNTs on the Strain‐Sensing Performance of TPU/PANI Electrospun Nanofibres

ABSTRACTThe increasing demand for flexible electromechanical devices with superior stretchability, durability, thermal stability and sensitivity has driven the development of new smart functional materials to replace conventional semiconductors. This study utilises combining electrospinning and in situ polymerisation to fabricate four types of thermoplastic polyurethane/polyaniline (TPU/PANI) nanofibrous membranes with varied fibre orientation and multiwalled carbon nanotubes (MWCNTs) incorporation. The combined effects of material composition and fibre alignment on strain‐sensing performance were systematically explored. All membranes exhibited stable, symmetric ohmic behaviour under strain, with current decreasing as strain increased. Remarkable repeatability and stability were observed in cyclic current–time tests. MWCNTs addition significantly enhanced conductivity, with aligned fibres further boosting performance. Gauge factor (GF) measurements revealed that aligned TPU/PANI mats had GFs of 7 (0%–18% strain) and 14.3 (18%–40%), while aligned TPU/MWCNTs/PANI mats had GFs of 5.2 (0%–13%) and 7.3 (13%–40%). Random TPU/PANI mats showed GFs of 13.9 (0%–11%) and 23.3 (11%–40%) and random TPU/MWCNTs/PANI mats had GFs of 13.9 (0%–19%) and 24.7 (19%–40%). Each configuration demonstrated suitability for specific applications, with random TPU/MWCNT/PANI mats exhibiting the best overall performance. This research provides critical insights into optimising flexible strain sensors by tuning both material composition and fibre orientation.

Conductive Graphene–Polyethylene Terephthalate Composite Yarns with Synergistic Multiwalled Carbon Nanotube Additives by Melt‐Spinning

Conductive graphene yarns are pivotal for embedding electronic and intelligent capabilities into fabrics. The study presents successful fabrication of conductive graphene–polyethylene terephthalate (PET) composite yarns with synergistic multiwalled carbon nanotube (MWCNT) additives through the melt‐spinning process, a widely used industrial method for polymer yarn manufacturing. The integration of MWCNTs significantly improves yarns’ electrical conductivity, achieving nearly a 100‐fold increase compared to MWCNT–PET composite yarns. The electrical performance of these yarns is primarily determined by interfacial contacts between conducting nanomaterials, which can be conceptualized as quantum tunneling barriers with multiple molecular energy levels at their extremities. Employing the Simmons model, the current–voltage characteristics is analyzed through a segmented fitting approach to extract critical barrier parameters. The equivalent barrier height and width remain constant across variations in applied voltage, nanomaterial concentration, and temperature. However, the effective total contact area increases significantly with higher nanomaterial contents, thereby substantially boosting the yarns’ electrical conductivity. The larger graphene size (≈200 nm) in comparison with the MWCNT diameter (≈5 nm) results in a substantially greater interfacial area at graphene–MWCNT contacts compared to MWCNT–MWCNT contacts. This disparity in contact area is the primary factor contributing to synergistic enhancement of electrical conductivity in graphene–PET composite yarns.

Study on the electromagnetic wave absorption performance of dual-loss type composite MWCNT/CIP/GF/EP

Abstract The electromagnetic properties of single-loss glass fiber (GF) absorbing composites with the addition of multi-walled carbon nanotube (MWCNT) particles and single-loss glass fiber (GF) absorbing composites with the addition of carbonyl iron powder (CIP) particles in the X-band were studied. Using CST electromagnetic simulation combined with experiments, dual-loss multi-walled carbon nanotube/carbonyl iron powder/glass fiber/epoxy (MWCNT/CIP/GF/EP) resin absorbing composites were designed and prepared. The effects of thickness ratio and periodic layering on the absorbing properties of dual-loss glass fiber absorbing composites were investigated. The results show that by changing the thickness ratio and periodic layering, the impedance matching and attenuation characteristics of the dual-loss glass fiber absorbing composites can be altered, thereby affecting the overall absorbing performance. The optimal group exhibited a maximum reflection loss of -55.3 dB at 8.5 GHz, with an effective absorption bandwidth of 3.0 GHz, covering 71.4% of the X-band.

On the influence of multi-walled carbon nanotube additives on the rheology of hydrocarbon-based drilling fluids

On the influence of multi-walled carbon nanotube additives on the rheology of hydrocarbon-based drilling fluids

Evaluation of Fracture Durability and Wear Resistance Properties for Orthopaedic Implant Application

Hydroxyapatite (HA) coated metallic substrates are commonly used for load-bearing orthopedic implants. In the present work Titanium grade 2 and Titanium grade 5 substrates were coated with hydroxyapatite and hydroxyapatite reinforced with 5% (by wt.) multiwalled carbon nanotubes (MCNT) separately using plasma spray coating. The wear behavior of these coated substrates was studied with the simulated body fluid (SBF) having a pH between 7.20 to 7.40. Fracture toughness and wear resistance of HA reinforced with 5 % (by wt.) MCNT composite coating was found to be higher as compared to pure HA coating. This improvement is by virtue of inherent mechanical properties and the crack bridging effect offered by MCNT. The addition of MCNT also helped in restricting crack propagation in the coatings. As evident from SEM images, abrasive and adhesive wear mechanism were observed which reduces greatly with reinforcement of MCNT.

Structural and morphological studies of g-C3N4-functionalized MWCNTs nanocomposite for sunlight-responsive photocatalytic activity

Photocatalytic degradation of organic contaminants has been proven to be one of the greatest economical and efficient techniques to address environmental pollution problems. Multi-walled carbon nanotubes (MWCNTs)/g-C3N4 (GCN) nanocomposites (NCs) were synthesized by a hydrothermal process aided by ultrasound to produce active photocatalysts. The effective synthesis of GCN, MWCNTs, and MWCNTs/GCN NCs was confirmed by X-ray diffraction (XRD) patterns. The fabrication of GCN nanosheets (NSs), the nanotubular structure of MWCNTs, and a network of neuron-like structures for MWCNTs/GCN NCs were all revealed by structural and morphological characterization. The elemental mapping of NCs containing the suitable quantity of MWCNTs revealed a uniform distribution of the sample's component elements. When the optical properties of the fabricated nanomaterials were examined by employing UV–visible spectroscopy, the results revealed a blue shift (a shift of maximum absorption to the UV region), which suggests that the addition of MWCNTs increased the band-gap energy. The behaviour of e––h+ pair recombination was revealed by measuring the charge carrier movement and trapping efficiency using photoluminescence (PL) spectroscopy. Crystal violet (CV) dye was photocatalytically degraded using prepared NCs in the presence of sunlight, and the synergistic effects of GCN and MWCNTs were examined. With a degradation efficiency of 99.32 %, MWCNTs/GCN NCs demonstrated the best sunlight-irradiated photocatalytic activity for CV degradation. The degradation of CV was discovered to follow pseudo-first-order kinetics. Throughout five consecutive studies, the NCs demonstrated the highest levels of catalytic efficiency and recyclability, with 5 % reduced degrading activities. The trapping tests showed that the primary reactive species involved in the breakdown of CV were the •O2– and •OH radicals.

Analyzing the Reinforcement of Multiwalled Carbon Nanotubes in Vulcanized Natural Rubber Nanocomposites Using the Lorenz–Park Method

In this study, multiwalled carbon nanotubes (MWCNTs) were incorporated into vulcanized natural rubber (VNR) matrixes to create nanocomposites with improved mechanical, thermal, and electrical properties. The interfacial interaction of the MWCNTs with the VNR matrix was quantitatively evaluated based on the crosslink density value calculated using the Flory–Rehner methodology. Various rheometric parameters were influenced by the addition of the MWCNTs, including minimum torque (ML), maximum torque (MH), and scorch time (tS1). The MWCNTs significantly enhanced the vulcanization of the composites based on the VNR matrix. This study highlights the impact of MWCNTs on crosslink density, improving mechanical properties and reducing swelling in the VNR matrix. We discovered that the MWCNTs and the VNR matrix interact strongly, which improved the mechanical properties of the matrix. The MWCNTs improved the hardness, tensile strength, and abrasion resistance of the VNR/MWCNT nanocomposites. Based on dynamic mechanical analysis, MWCNT incorporation improved stiffness as indicated by a change in storage modulus and glass transition temperatures. The addition of MWCNTs to the VNR/MWCNT nanocomposites significantly improved their electrical properties, reaching a percolation threshold where conductive pathways were formed, enhancing their overall conductivity. Overall, this study demonstrates the versatility and functionality of VNR/MWCNT nanocomposites for a variety of applications, including sensors, electromagnetic shielding, and antistatic blankets.

UV/thermal dual-cured MWCNTs composites for pipeline rehabilitation: Mechanical properties and damage analysis

Deformation and damage in underground pipelines remain challenging to monitor over the long term due to sensor degradation caused by corrosive substances present in the pipelines. This study investigates the potential of incorporating multi-walled carbon nanotubes (MWCNTs) into ultraviolet-cured-in-place pipe (UV-CIPP) material, a widely adopted trenchless repair technique, to enhance performance and enable deformation monitoring. A UV/thermal dual-curing strategy is introduced to mitigate the significant reduction in light transmittance caused by the inclusion of MWCNTs in the composite material. The addition of MWCNTs led to a 94.86 % reduction in light transmittance through glass fibers. However, this issue was effectively resolved through the incorporation of thermal curing, allowing for the production of ultra-high-strength composites using only three layers of fibers within a short curing time. Under optimal conditions (0.2 wt% MWCNTs with the impregnation layer on top), the flexural strength and modulus reached 442.75 MPa and 15.58 GPa, respectively, marking improvements of 14.01 % and 45.2 % over the base material. Additionally, the hardness on the composite's backside increased by 10.95 % compared to the front, indicating enhanced reinforcement. The tensile strength of braided glass fibers improved by 42.31 % and 197.54 % with the addition of 0.2 wt% and 1.0 wt% MWCNTs, respectively. Failure modes varied based on the location of the sensing layer, but all specimens eventually failed due to resin cracking, delamination of the MWCNTs-impregnated layer, and fiber fractures. The UV/thermal dual-cured composite material developed for pipeline rehabilitation in this study exhibits ultra-high strength and shows significant potential for multifunctional sensing applications.

The effects of MWCNT-STF on the impact resistance of fibre metal laminates

Fibre metal laminates (FMLs) have been widely used in the aerospace and transportation industries, due to their excellent impact and fatigue resistance. However, it is challenging to further improve the impact resistance of FMLs. In this study, shear thickening fluids (STFs) with different ratios of silicon nanoparticles to polyethylene glycol (PEG) were first produced to obtain the STF with optimized performance. Then, multiwalled carbon nanotubes (MWCNTs) were added to the STF to produce MWCNT-STF to further improve its shear thickening behaviour. The rheological test results have shown that the MWCNT-STF with the composition ratio of 30 wt% PEG200+0.2 wt% MWCNTs+69.8 wt% SiO2 demonstrates the best shear thickening function, with the peak viscosity being enhanced by 365 % but the critical shear rate reduced by 69 % compared with the original STF. The MWCNT-STF was then impregnated to Kevlar fabric by ultrasonic impregnation process. The experimental results show that MWCNTs contribute the best adhesion to Kevlar fabric when the ratio of MWCNT-STF to alcohol is 1:2, with the optimal add-on ratio as 53 %. The yarn pulling-out tests show that the addition of MWCNTs to STF improves the friction between the fabric yarns, which in turn increases their shear resistance. Then STF and MWCNT-STF Kevlar fabrics were integrated to FML manufacturing. The quasi-static perforation tests indicate that MWCNT-STF helps improve the specific energy absorption of the MWCNT-STF FMLs by up to 16 %, but with limited impact on the peak perforation force. More effectively, the low velocity impact tests show that the 3/2 FMLs made with 1, 2, and 3 layers of MWCNT-STF Kevlar fabric have an enhancement on their peak impact force by 20, 36 and 38 %, while on specific energy absorption by 30, 40 and 42 %, respectively, compared to 3/2 STF FMLs counterparts.

Synergistic effect of nickel and graphite powders on the thermoelectric properties of ultra-high-performance concrete containing steel fibers and MWCNTs

The study investigates the influence of multi-walled carbon nanotubes (MWCNTs) and conductive powders, namely nickel powder (NP) and graphite powder (GP), on the mechanical and thermoelectric properties of ultra-high-performance concrete (UHPC). Flowability tests indicate that the addition of MWCNTs and conductive powders affects the flow diameter, with higher concentrations resulting in decreased flowability. Thermalgravimetric analysis and Fourier transform infrared spectroscopy reveal that the enhancement of the hydration reaction by 0.1 % MWCNTs in UHPC reaches saturation at this concentration. Pore structure analysis demonstrates a reduction in porosity and a denser structure upon the addition of 0.1 % MWCNTs. Mechanical tests indicate that the incorporation of 0.1 % MWCNTs enhances compressive and tensile strengths, whereas the introduction of 0.3 % MWCNTs diminishes the mechanical performance. Moreover, the electrical conductivity and thermoelectric effect are enhanced with the addition of MWCNTs and conductive powders. However, a decline in thermoelectric effect is observed when 0.3 % MWCNTs are added, although the conductivity remained high. The optimal thermoelectric performance is achieved with the combination of 0.3 % MWCNTs and 5 % NP, yielding a maximum power factor (PF) of 2148.2 μW/m·K2 and a figure of merit (ZT) of 4.9 × 10⁻7.

Carbon nanotube manipulates crystallization kinetics and viscoelastic behavior of PP/EBC blends

AbstractPolypropylene (PP) offers numerous benefits to industrial applications due to its excellent processability and cost‐effectiveness. However, the widespread utilization of this commodity thermoplastic is constrained by its inherently low‐impact resistance. Herein, we suggest a ternary system with the addition of ethylene‐butene copolymer (EBC) and multiwalled carbon nanotubes (MWCNTs) to improve the overall performance of PP. We unveil the role of MWCNTs on the crystalline behavior of the PP/EBC blends when various ratios are considered. The calculated half‐time crystallization from the Avrami equation indicates that 1.5 wt% MWCNTs accelerate the crystallization of the PP/EBC blend nearly threefold. The formation of a semisolid microstructure is also reported using the rheological measurements. An upturn in complex viscosity, along with a frequency‐independent storage modulus, indicates strong interactions between MWCNTs and polymer chains. We confirm such robust interactions by employing temperature ramp sweep on the prepared nanocomposites as the decomposition temperature of the materials shifts to higher values. The dynamic mechanical analysis further interprets the role of MWCNTs as compatibilizers by bridging the gap between the glassy temperature of PP and EBC components.Highlights Theoretical prediction of the MWCNTs localization in the PP/EBC blends. Depicting the solid‐like behavior and viscosity upturn of PP/EBC/MWCNTs. Decelerating polymer chain relaxation led by nucleation role of MWCNTs. Formation of larger and more imperfect crystals upon the addition of MWCNTs. Faster crystallization kinetics in the PP/EBC/MWCNTs nanocomposites.

Karakteristik Pembakaran Droplet Campuran Metil Oleat – Etanol dengan Penambahan Multi -Walled Carbon Nanotubes

This research intended to investigate the combustion characteristics of methyl oleic – ethanol blend with OH functionalized multi-walled carbon nanotubes (MWCNT-OH) addition. Methyl oleic is an unsaturated fatty acid methyl ester, which is a constituent of various biodiesels. The observed fuel was a mixture of Methyl oleic with 20% vol of ethanol. MWCNT-OH content was varied by 100 ppm, 200 ppm, 300 ppm, 400 ppm, and 500 ppm (wt based). The presence of ethanol in the droplets is intended to promote the microexplosion phenomenon, generating smaller droplets and a shorter burning time. The experimental results show that the MWCNT-OH addition on the droplet of Methyl oleic – ethanol blend decreased the ignition delay and droplet burning time, while the constant burning rate and droplet temperature (and flame temperature) were increased. Reducing ignition delay time due to the higher thermal conductivity of nanofluid droplets results in more effective heat absorption from the environment and better heat transport inside the droplet. Hence, droplet vaporization, flammable mixture formation and ignition occur in a shorter time. Furthermore, this condition encourages a higher burning rate and a lower droplet burning time. The higher droplet and flame temperatures are related to the higher heating value of the methyl oleic – ethanol – MWCNT-OH mixture and higher droplet burning rate, which results in a higher heat release rate.

Optimization of Al6061 Nanocomposites Production Reinforced with Multiwalled Carbon Nanotubes

This study investigates the impact of multi-walled carbon nanotubes (MWCNTs) on the microstructure and mechanical properties of Al6061 nanocomposites. The MWCNTs were uniformly dispersed in the aluminum alloy matrix using ultrasonication following cold pressing and sintering in a vacuum. The effect of the sintered temperature on the microstructure and mechanical properties of the nanocomposites was evaluated. The addition of MWCNTs resulted in grain refinement, with the nanocomposites exhibiting smaller and more uniformly distributed grains than the pure Al6061 matrix, particularly at lower sintering temperatures of 580 and 600 °C. The nanocomposites also demonstrated an increase in hardness, with peak values observed at 580 °C, primarily due to the effective dispersion of MWCNTs, which restrict dislocation movement and reinforce grain boundaries. While higher sintering temperatures led to significant grain growth and less uniform hardness distribution, lower temperatures favored finer grain structures and more homogeneous hardness profiles. The results suggest that the optimal sintering temperature for achieving the best balance between microstructure and mechanical properties is 580 °C. However, the study also highlights the need for optimized dispersion techniques to achieve a more uniform distribution of MWCNTs.

Combined toxicity of multiwall carbon nanotubes and cadmium on rice (Oryza sativa L.) growth in soil

The comprehensive effects of nanoparticles and coexisting heavy metals on plant growth are still unclear, especially in soil medium. The single and combined effects of multiwall carbon nanotubes (MWCNTs) and cadmium (Cd) on rice (Oryza sativa L.) growth were examined in this study through a 4 months pot experiment in 2022. Rice plants were exposed to different concentrations of MWCNTs (100 and 500 mg kg−1) in the presence of 5.0 mg kg−1 Cd stress. At the tillering stage, the 500 mg kg−1 MWCNTs addition reduced plant height by 8.0% and increased soluble protein content in the leaves by 13.7%, demonstrating that a single MWCNTs had a slight negative impact on rice growth. When exposed to Cd stress, the inclusion of 500 mg kg−1 MWCNTs led to a 6.7%–9.0% decrease in bioavailable Cd level in soil, resulting in considerable reductions in Cd content in roots (23.4%–29.9%), shoots (24.5%–28.3%) and grains (28.3%–66.2%). Compared to the single Cd treatment, the O. sativa L. leaves treated with Cd and MWCNTs (500 mg kg−1) had considerably reduced levels of malondialdehyde (MDA), soluble protein, and activities of antioxidant enzymes (POD, CAT, and SOD). The findings of this study indicated that appropriate concentrations of MWCNTs application in soil could alleviate Cd-induced toxicity on rice growth.

Engineering bioactive MWCNT-reinforced hydroxyapatite coatings on Ti29Nb5Zr alloy by plasma electrolytic oxidation method: A comprehensive approach to dental implant surface optimization

Titanium-niobium-zirconium (TiNbZr) alloys represent a promising class of newly developed titanium-based biomaterials, engineered to exhibit superior properties for biomedical applications. This study investigates the influence of hydroxylated multi-walled carbon nanotubes (MWCNTs) on the surface properties of hydroxyapatite coatings prepared by the plasma electrolytic oxidation (PEO) method for implant applications. The optimal concentration of MWCNTs in the PEO coating was determined based on the superior surface, electrochemical, and biological properties obtained. The incorporation of MWCNTs led to an enhancement in surface roughness from Ra 0.06 ± 0.02 to Ra 0.618 ± 0.03 µm, improved wettability with a decrease in contact angle from 63.03° ± 1.1–28.29° ± 0.07, and a reduction in elastic modulus from 77.20 ± 2.26 GPa to 54.50 ± 2.22 GPa. Furthermore, electrochemical corrosion resistance analysis revealed an increase in inner passivation resistance up to 2.24 × 10 ×7 Ω.cm2 with the addition of MWCNTs. Antibacterial activity analysis demonstrated that the optimal concentration of MWCNTs resulted in a 3.1-fold and 2.7-fold reduction in E. coli and S. aureus bacteria, respectively, compared to uncoated samples. Cell viability against MC3T3-E1 cells showed a 25 % higher viability with MWCNTs than uncoated substrates.

Experimental investigation of performance, emission, and combustion characteristics of a diesel engine using blends of waste cooking oil-ethanol biodiesel with MWCNT nanoparticles

In this study, blends of 5 % and 10 % ethanol with waste cooking oil biodiesel are mixed with Multi-Walled Carbon Nanotubes (MWCNT) at a concentration of 30 ppm. MWCNTs, known for their high surface area and unique properties, are added to potentially enhance combustion efficiency and reduce emissions. These blends are then tested in a diesel engine to evaluate their performance, emission and combustion characteristics using Design of experiment technique. After conducting various experiments and analyses, the blend of 20 % biodiesel, 10 % ethanol, and 30 ppm MWCNT was identified as the most optimal due to its favorable engine characteristics. Brake Thermal Efficiency (BTE) was increased from 3.1 % to 3.4 % with the addition of MWCNTs, indicating enhanced fuel efficiency. Moreover, average Fuel Consumption is decreased from 2.2 % to 2.5 %, suggesting improved fuel utilization. Using MWCNT 30 ppm in B20 ethanol blends (MWCNT 30 ppm B20+E10) resulted in 35 % reduction in nitrogen oxide (NOx) emissions, 37 % reduction in CO emissions and 39 % reduction in HC emissions. Hence MWCNTs demonstrated effectiveness in mitigating harmful exhaust emissions The optimized values for all parameters fall within acceptable ranges, indicated successful optimization using Response surface methodology. Additionally, statistical analysis reveals that the machine learning- XGBoost model outperformed all other advanced machine learning models across all tested metrics, including MSE, MAE, and R-square.

Enhanced Tribological Properties of Nanolubricants with Multiwalled Carbon Nanotube Additives

Abstract This study aims to achieve novel tribological properties by utilizing industrial-type multiwalled carbon nanotubes (MWCNTs) as lubrication additives in 20W-50 engine oil, in parts per million (ppm). Nanolubricants consisting of various amounts of MWCNTs were prepared and subjected to ball-on-disk tests to observe tribological characteristics. For ball-on-disk tests, friction coefficient data were obtained during testing, whereas wear characteristics were achieved from test samples through imaging and processing methods. Spectroscopic analyses were done to collect additional data about the existence of MWCNTs on the friction surfaces. The data acquired were analyzed according to theoretical bases. It has been found that the best results as antiwear properties are obtained at 600-ppm MWCNT addition by a wear decrease of 81.02 % and decreased severity of wear tracks, where antifriction characteristics were found to be enhanced at 200 ppm by a friction coefficient decrease of 8.07 %. However, 600-ppm MWCNT addition also constitutes a limit value whereby further addition can cause an increase in the wear of friction pairs. It has been shown that MWCNTs can enhance antifriction and antiwear properties even in ppm-level amounts, which can be considered as lower amounts of nanoadditives when compared to the literature and can present economically suitable lubrication solutions.

Facile and controllable hybrid-nanoengineering of MWCNTs/Au@ZIF-8 and AuPt@CeO2 based sandwich electrochemical aptasensor for AFB1 determination in foods and herbs

Herein, a sandwich electrochemical sensing strategy for aflatoxin b1 (AFB1) detection based on hybrid-nanoengineering was presented. First, Au nanoparticle was doped into zeolitic imidazolate framework-8 (ZIF-8) to form Au@ZIF-8 by in-situ growth method, followed by multi-walled carbon nanotubes (MWCNTs) addition to synthesize MWCNTs/Au@ZIF-8 via self-assembly. The structural “confinement effect” of ZIF-8 afforded a microenvironment for Au nanoparticles and SMCNTs in a certain spatial region, giving MWCNTs/Au@ZIF-8 excellent electrochemical property as the substrate material. In addition, Au-Pt bimetallic nanoparticle, which exhibited excellent stability and catalytic activity was loaded on the hollow cerium oxide (CeO2) to form AuPt@CeO2 nanoparticle through one-step aqueous phase reduction. Owning to its high surface-to-volume ratio, satisfied electron transfer efficiency and biocompatibility, massive toluidine blue (TB) and AFB1 antibody (Ab) could be modified on the AuPt@CeO2 to form AuPt@CeO2-Ab-TB, which acted as signal tag for the ultrasensitive assay of AFB1. The proposed electrochemical sensing system exhibited wide detection range (2 × 10-5 − 20 ng/mL) and low detection limit (2.13 fg/mL), which has been successfully applied to AFB1 determination in four real samples. The hybrid nanoengineering presented in this work is an active attempt to prepare high-performance substrate material and signal tag, which provides a new insight for the development of highly sensitive and specific electrochemical sensing systems.

Reinforcing β-tricalcium phosphate scaffolds for potential applications in bone tissue engineering: impact of functionalized multi-walled carbon nanotubes

Beta-tricalcium phosphate (β-TCP) scaffolds manufactured through the foam replication method are widely employed in bone tissue regeneration. The mechanical strength of these scaffolds is a significant challenge, partly due to the rheological properties of the original suspension. Various strategies have been explored to enhance the mechanical properties. In this research, β-TCP scaffolds containing varying concentrations (0.25–1.00 wt%) of multi-walled carbon nanotubes (MWCNT) were developed. The findings indicate that the addition of MWCNTs led to a concentration-dependent improvement in the viscosity of β-TCP suspensions. All the prepared slurries exhibited viscoelastic behavior, with the storage modulus surpassing the loss modulus. The three time interval tests revealed that MWCNT-incorporated β-TCP suspensions exhibited faster structural recovery compared to pure β-TCP slurries. Introducing MWCNT modified compressive strength, and the optimal improvement was obtained using 0.75 wt% MWCNT. The in vitro degradation of β-TCP was also reduced by incorporating MWCNT. While the inclusion of carbon nanotubes had a marginal negative impact on the viability and attachment of MC3T3-E1 cells, the number of viable cells remained above 70% of the control group. Additionally, the results demonstrated that the scaffold increased the expression level of osteocalcin, osteoponthin, and alkaline phosphatase genes of adiposed-derived stem cells; however, higher levels of gene expersion were obtained by using MWCNT. The suitability of MWCNT-modified β-TCP suspensions for the foam replication method can be assessed by evaluating their rheological behavior, aiding in determining the critical additive concentration necessary for a successful coating process.