Multi-walled carbon nanotubes are engineered nanomaterials (ENMs) that have a fiber-like structure which may be a concern for the development of cellular senescence. Premature senes-cence, a state of irreversible cell cycle arrest, is implicated in the pathogenesis of chronic lung dis-eases such as pulmonary fibrosis (PF). However, the crosstalk between downstream pathways mediating fibrotic and senescent responses of MWCNTs is not well defined. Here, we exposed human bronchial epithelial cells (BEAS2B) to MWCNTs for up to 72 hours and demonstrate that MWCNTs increase reactive oxygen species production (ROS) accompanied by inhibition of cell growth and proliferation. In addition, exposure resulted in the increase of p21 protein and senes-cence associated β-galactosidase (SA β-gal) activity. We also determined that co-exposure with the cytokine, transforming growth factor-β (TGF-β) exacerbated cellular senescence indicated by increased protein levels of p21, p16, and γH2A.X Furthermore, the production of fibronectin and plasminogen activator inhibitor (PAI-1) was significantly elevated with the co-exposure compared to MWCNTs or TGF-β alone. Together, this suggests that the senescence potential of MWCNTs may be enhanced by pro-fibrotic mediators in the surrounding microenvironment.

In this paper we propose a simple procedure to obtain multi-walled carbon nanotubes (MWCNT) decorated with TiO₂-Ag nanoparticles (MWCNT-TiO₂-Ag). MWCNT were decorated with TiO2-Ag via combined functionalisation with -OH and –COOH groups and polymer wrapping technique using poly(allylamine hydrochloride) (PAH). TiO₂ modified Ag nanoparticles were synthesized through Pechini method using mixture of acetylacetonate-modified titanium (IV) isopropoxide with silver nitrate (the Ag+/Ti4+ atomic ratio, is 0.5, 1,0, 1.5, 2.0 and 2.5 %, respectively) and the L(+)-ascorbic acid, as reducing agents. XRD analysis revealed the formation of nanocomposite containing CNT, TiO₂ (anatase and rutile) and Ag. By SEM was evidenced the presence of the nanoparticles on MWCNT surface. The increases of the ratio between Ag⁺ and Ti⁴⁺ decrease the band gap energy of the samples. In Raman spectra the characteristic vibration of the TiO₂, Ag and C atoms of graphite are identified. The photocatalytic activity of the MWCNT-TiO₂-Ag nanocomposite was assessed by examining the degradation of Allura red (E129) aqueous solution under UV irradiation. The dye photodegradation process follows a pseudo – first – order kinetic with respect to the Langmuir – Hinshelwood reaction mechanism.

The dopamine and uric acid are primary products of purine metabolism and they coexist in serum and the extracellular fluid of the central nervous system. Some diseases of the human body are due to abnormal levels of uric acid and dopamine. Thus, the clinical diagnosis of some diseases needs a sensitive and simultaneous analysis of uric acid and dopamine. In this study, a novel conductive composite film containing multi-walled carbon nanotubes (MWTs) with cooper phthalocyanine attached to acrylate polymer (MWCNTs-CuMAPC-PnBA) was fabricated and dropped on a glassy carbon electrode and used for the simultaneous determination of Uric Acid (UA) and dopamine (DA). The modified glassy carbon electrode showed satisfactory electrocatalytic activity toward dopamine and uric acid. Low detection limits were achieved at 0.174 µM of DA and 6.87 µM of UA and the linear detection ranges of DA and UA are 5-200 µM and 20-250 µM respectively. The proposed sensing system based on the modified GCE offers promising results for rapid, cost-effective and selective simultaneous detection of uric acid and dopamine. Also, the complex modified electrode showed satisfactory results to detecting simultaneously UA and DA in real human samples (human Urine) via the standard addition method.

We have established earlier a cell line from the human limbal area to study cell growth and response to the toxic effects of antibiotics used in ophthalmology. In the recent work, the effect of multi-walled carbon nanotubes (MWCNTs) in cornea damage was investigated in vitro and in vivo in mice. In the in vitro experiments, the physiological effects of multi-walled carbon nano-tube (MWCNT) bundles on corneal wound healing were mimicked in vitro by a reepithelization limbal stem cell model. Murine in vivo experiments were performed with intact, non-functionalized MWCNTs to confirm the validity of in vitro tests. The MWCNTs of 10 -30 nm outer diameter at low concentration (5 µg/ml) did not interfere with the wound healing of the damaged limbal cell monolayer. Higher than 50 µg/ml concentrations: a) generated MWCNT aggregates, b) restrained the movement and prolonged the time of wound healing, c) increased the amplitudes of the oscillations of the cells, and d) resulted in scar formation affecting both cor-neal function and refraction. Chromatin condensation, a sensitive test of the viability of cells, including limbal stem cells revealed that the presence of a low concentration of nanotubes (5 µg/ml), did not significantly affect the viability of limbal cells. Chromatin condensation was completed and metaphase chromosomes were seen at higher MWCNT concentration proving that their aggregates did not affect the viability of limbal cells. This concentration of MWCNTs (5 µg/ml) did impact neither the reepithelization in vitro nor in vivo in the scratched eyes of mice. Scar formation took place at higher than 50 µg/ml concentrations and the healing of the cornea was prevented by the lack of movement of increasingly larger macroaggregates. In vivo murine experiments vali-dated in vitro monolayer regrowth followed by time-lapse microscopy portraying realistically the reepithelization of the damaged cornea that process was gradually slowed down by macro aggregate formation and caused the scarring of the cornea.

This research illustrates modification of multi-walled carbon nanotubes (MWCNT) by ZrO2/Pb to construct nanocomposites (MWCNT/ZrO2/Pb-NCs) by simple precipitation technique and subsequently examine its ability for adsorption of Amido black (AB) and Eosin B (EB) dyes in binary system. The present nanocomposites investigation by FESEM, XRD, FTIR, and EDX analysis, reveal its as-synthesized crystalline nature with cubic morphology and average particle size 30–50 nm. The present nano-adsorbent represent high efficiency for AB and EB adsorption from aqueous solution, while dependency of variables including pH, initial concentration of dyes, contact time and MWCNT/ZrO2/Pb-NCs mass were analyzed by central composite design (CCD). The predicted maximum removal percentage was 95% removal for both dyes is consequence of adjustment of operational conditions at pH of 6.0; 0.05 g MWCNT/ZrO2/Pb-NCs; 15 min stirring at 15 mg L-1 for both dyes. The Langmuir as applicable for representation and description of reveal data of adsorption with adsorption capacity of 15.46 and 16.92 mg g-1 for AB and EB, respectively. Pseudo-first order model owing to its high correlation coefficient and closeness of experimental and theoretical data well represented behavior of corresponding adsorption system. Mechanism examination strongly proof high contribution of external mass transference as the main rate-controlling step. The successful regeneration of MWCNT/ZrO2/Pb-NCs suggested their usefulness in wastewater treatment and its ability of environmental management.

Premature failure and degradation of layers are the main problems for transportation infrastruc-ture. Addressing these issues necessitates implementing structural health monitoring (SHM) for transportation layers. This strategic approach is instrumental in mitigating maintenance expenses, prolonging the operational lifespan, and preventing accidents resulting from abrupt layer col-lapse. To this end, this research investigated the stress/strain and damage detection capabilities of a self-sensing cementitious composite developed for potential utilization in the construction of an intelligent subgrade layer. The prepared self-sensing cementitious composite consisted of 10% cement and hybrid conductive fillers, including multiwalled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) in sand. Initial findings reveal that the electrical resistivity of the composite is significantly affected by the concentration of MWCNTs/GNPs, with a minimum concentration of more than 0.5% needed to achieve a responsive cementitious composite. More-over, the piezoresistive analysis indicates that an increase in the concentration of MWCNTs/GNPs and stress levels leads to an improvement in the stress/strain sensing perfor-mance. When the self-sensing cementitious composite is subjected to equivalent stress levels, variations in the FCR exhibit an increasing trend with decreasing resilient modulus, stemming from a decrease in stiffness due to the increased concentration of MWCNTs/GNPs. Additionally, the EIS analysis demonstrates a contraction for the Nyquist curves under compressive ramp loading prior to failure, followed by the expansion of these curves postfailure. Scanning electron microscopy (SEM) images visually showcase the bridging effects of MWCNTs and the filling ef-fects of GNPs within the composite structure.