Toxicity Of Carbon Nanotubes Research Articles

Low Toxicological Impact of Commercial Pristine Multi-Walled Carbon Nanotubes on the Yeast Saccharomyces cerevisiae.

Carbon nanotubes (CNTs) have attracted the attention of academy and industry due to their potential applications, being currently produced and commercialized at a mass scale, but their possible impact on different biological systems remains unclear. In the present work, an assessment to understand the toxicity of commercial pristine multi-walled carbon nanotubes (MWCNTs) on the unicellular fungal model Saccharomyces cerevisiae is presented. Firstly, the nanomaterial was physico-chemically characterized, to obtain insights concerning its morphological features and elemental composition. Afterwards, a toxicology assessment was carried out, where it could be observed that cell proliferation was negatively affected only in the presence of 800 mg L−1 for 24 h, while oxidative stress was induced at a lower concentration (160 mg L−1) after a short exposure period (2 h). Finally, to identify possible toxicity pathways induced by the selected MWCNTs, the transcriptome of S. cerevisiae exposed to 160 and 800 mg L−1, for two hours, was studied. In contrast to a previous study, reporting massive transcriptional changes when yeast cells were exposed to graphene nanoplatelets in the same exposure conditions, only a small number of genes (130) showed significant transcriptional changes in the presence of MWCNTs, in the higher concentration tested (800 mg L−1), and most of them were found to be downregulated, indicating a limited biological response of the yeast cells exposed to the selected pristine commercial CNTs.

Combination of Mussel Inspired Method and “Thiol-Michael” Click Reaction for Biocompatible Alginate-Modified Carbon Nanotubes

Carbon nanotubes (CNTs) have attracted great interest in biomedical fields. However, the potential toxicity and poor dispersion of CNTs have greatly limited its application. In this work, a mussel-inspired method combined with the “thiol-Michael” click reaction was used to modify the surface of CNT and improve its properties. Firstly, a CNT was treated with dopamine, and then alginate grafted with L-cysteine was anchored onto the surface of CNT via click reaction, which realized the long-time dispersion of CNT in water. Furthermore, the in vitro test also demonstrated that the alginate may improve the biocompatibility of CNT, and thus may broaden the application of CNT in the biomedical field.

The combined toxicity and mechanism of multi-walled carbon nanotubes and nano zinc oxide toward the cabbage.

The natural environment is a complex system, and there is never only one kind of nanomaterial entering the environment. However, many studies only considered the plant toxicity of one kind of nanomaterial and do not consider the influence of two or more kinds of nanomaterials on plant toxicity. Multi-walled carbon nanotubes (MWCNTs) and zinc oxide nanoparticles (ZnO NPs) are two common and widely used nanomaterials in water environment, so these two kinds of nanomaterials were chosen to explore the effects of their combined toxicity on cabbage. This study investigated the toxicity of MWCNTs combined with ZnO NPs on cabbage by measuring the length of roots and stems, chlorophyll content, oxidative stress, antioxidant enzyme activity, metal element content, and root scanning electron microscopy. The toxicity of single MWCNTs toward cabbage was attributed to direct oxidative damage, while the toxicity of single ZnO NPs toward cabbage was due to the high level of zinc concentration. Moreover, ZnO NPs (10 mg/L) ameliorated MWCNTs toxicity toward cabbage by improving the activity of antioxidant enzymes. ZnO NPs (50 and 100 mg/L) because of the high content of zinc disrupted the balance of other metals in the plant and increased the toxicity of MWCNTs. In conclusion, the combined toxicity of different concentrations and types of nanomaterials should be considered for a more accurate assessment of environmental risks.

Safe-by-design strategies for lowering the genotoxicity and pulmonary inflammation of multiwalled carbon nanotubes: Reduction of length and the introduction of COOH groups

Potentially, the toxicity of multiwalled carbon nanotubes (MWCNTs) can be reduced in a safe-by-design strategy. We investigated if genotoxicity and pulmonary inflammation of MWCNTs from the same batch were lowered by a) reducing length and b) introducing COOH-groups into the structure. Mice were administered: 1) long and pristine MWCNT (CNT-long) (3.9 μm); 2) short and pristine CNT (CNT-short) (1 μm); 3) CNT modified with high ratio COOH-groups (CNT-COOH-high); 4) CNT modified with low ratio COOH-groups (CNT-COOH-low). MWCNTs were dosed by intratracheal instillation at 18 or 54 μg/mouse (∼0.9 and 2.7 mg/kg bw). Neutrophils numbers were highest after CNT-long exposure, and both shortening the MWCNT and addition of COOH-groups lowered pulmonary inflammation (day 1 and 28). Likewise, CNT-long induced genotoxicity, which was absent with CNT-short and after introduction of COOH groups. In conclusion, genotoxicity and pulmonary inflammation of MWCNTs were lowered, but not eliminated, by shortening the fibres or introducing COOH-groups.

An eclectic approach to monitor and manage the disposal of carbon nanotubes.

Nanotechnology, in general, and nanomaterials in particular, have conferred and are continuing to confer many benefits to mankind, just as the advent of "plastics" did in previous generations. In the case of carbon nanotubes, which can be produced in vast quantities, documented methods to manage this carbon nanotube waste by recycling and or safe disposal are so minimal that it is a matter of great concern that the paucity of studies on managing carbon nanotube waste may lead to complacency. The latter could be a trigger for human illnesses, through poor handling of carbon nanotube waste. The present study investigated ways to manage recycling and disposal of waste carbon nanotubes and a limited study of some aspects of the toxicity of waste carbon nanotubes in the environment. An eclectic approach was adopted for this study, involving an application and analysis of questionnaires, to ascertain the current practices used by practitioners in carbon nanotube research, as well as experimental work to determine the potential toxicity of carbon nanotubes. This investigation was undertaken to determine if a change from current practice is warranted in the light of the potential toxicity of carbon nanotubes (CNTs). Analysis of the questionnaires revealed the use of differing practices for the recycling and disposal of engineered nanomaterials (ENMs), implying that there is a dire need for a uniform code of practice. The toxicity study showed that carbon nanotubes did not kill earthworms in soil. However, worms were observed to be highly sensitive to increased concentrations of carbon nanotubes. The leaching in a soil column test showed that the movement of carbon nanotubes was inhibited, being confined mainly to the topmost layers of the soil. This is taken to imply that the water table is safe from possible contamination by CNTs.

Evaluation of the combined toxicity of multi-walled carbon nanotubes and cadmium on earthworms in soil using multi-level biomarkers

The coexistence of multi-walled carbon nanotubes (MWCNTs) with cadmium (Cd) in soil may cause the combined biological effects, but few study reported about their joint toxic effects on earthworms. Therefore, this study investigated the effects of sub-lethal levels of MWCNTs (10, 50, 100 mg/kg) and Cd (2.0, 10 mg/kg) on earthworms Eisenia fetida for 14 days. The changes in multi-level biomarkers of growth inhibition rate, cytochrome P450 isoenzymes (CYP1A2, 2C9 and 3A4), and small molecular metabolites (metabolomics) were determined. The toxic interaction between MWCNTs and Cd was characterized by the combination of the biomarker integration index (BRI), joint effect index concentration addition index (CAI), and the effect concentration addition index (EAI). The results showed that the single MWCNTs exposure caused insignificant change in most biomarkers, while the combined exposure of MWCNTs (50–100 mg/kg) and 10 mg/kg Cd led to significant changes in ten most important metabolites identified by metabolomics and activities of CYP1A2, 2C9, and 3A4. Compared with the toxicity of Cd alone, the combined toxicity of the mixture was significantly reduced. According to the integration of BRI and CAI/EAI, a clearly antagonistic interaction at relatively low effects was observed between MWCNTs and Cd. The responses of multiple biomarkers suggest the toxic action mode of the mixture on earthworms was related to the oxidative injury, and the disruption of amino acid, purine, and pyrimidine metabolism, and the urea cycle.

The combined toxicity and mechanism of multi-walled carbon nanotubes and nano copper oxide toward freshwater algae: Tetradesmus obliquus

Nanoparticles (NPs) are widely used for their special physical properties and released into the natural environment. When two types of NPs exist in the same environment, the presence of one type of NP may affect the properties of the other type of NP. This study investigated the toxic effects of multi-walled carbon nanotubes (MWCNTs) and copper oxide nanoparticles (CuO NPs) on Tetradesmus obliquus. Both NPs had toxic effects on algae, and the toxic effects of MWCNTs were significantly stronger than CuO NPs which the 96-hr median effective concentration to algae were 33.8 and 169.2 mg/L, respectively. Oxidative stress and cell membrane damage were the main reasons for the toxicity of NPs to algae, and they were concentration-dependent, and the existence of CuO NPs in some groups reduced cell membrane damage caused by MWCNTs which may because that CuO NPs formed heteroaggregation with MWCNTs, reducing the contact of nanoparticles with cell membranes, then reducing physical damage. Scanning electron microscopy (SEM) and transmission electron microscope (TEM) results indicated cell damage, the heteroaggregation of MWCNTs-CuO NPs and obvious nanoparticles internalization. In some groups, the presence of CuO NPs significantly reduced reactive oxygen species (ROS) level induced by MWCNTs. However, for the highest concentration group, the ROS level was much higher than that of the two NPs alone treatment groups, which might be related to the high concentration of MWCNTs promoting the internalization of CuO NPs. MWCNTs and CuO NPs affected and interacted with each other, causing more complex toxic effects on aquatic organisms.

Toxicity of amine-functionalized single-carbon nanotube (NH2 f-SWCNT) to Channel Catfish (Ietalurus Punetaus): Organ pathologies, oxidative stress, inflammation, and apoptosis

The rapid development of carbon nanotubes (CNTs) in the field of fish disease control and prevention raises concerns about the toxicity and safe use in fish. This study was performed to assess the effect on histological changes, oxidative stress related markers in response to various concentrations of amine-functionalized single carbon nanotubes (NH2 f-SWCNT) (1, 10 and 100 mg kg−1 fish) in Channel Catfish (Ietalurus Punetaus) for up to 10 days. Moreover, pro-inflammatory cytokine genes and apoptotic genes were analyzed to obtain a better understanding of molecular mechanism of NH2 f-SWCNT induced toxicity. As a result, intraperitoneal (i.p.) administration of NH2 f-SWCNT caused dose-dependent and time-dependent injuries in the sampled tissues. In comparison with the control groups, decrease of catalase (CAT) activity and superoxide dismutase (SOD), and increase of malondialdehyde (MDA) and lactin dehydrogenase (LDH) were observed in all treatments. Real-time PCR assay showed inflammatory response with dose-dependent increase of tumor necrosis factor alpha (TNFα) and transient increase of interleukin 1β (IL-1β) in the liver. NH2 f-SWCNT administration induced increase of p38 as well as caspase-3 in all treatments compared to the control groups, indicating the involvement of p38-MAPK cascade and caspase-3 cascade in liver cell apoptosis. Overall, we conclude that NH2 f-SWCNT exert effects by direct injury and indirectly oxidative stress, resulting in inflammation and apoptosis, which provides data for understanding of the biological mechanisms underlying the toxicity of CNTs in fish.

Purification use and toxicity of paramagnetic short multi-walled carbon nanotubes

ABSTRACT Carbon nanotubes (CNT) have high surface area and absorption capabilities and the absorption capacity of multi-walled CNTs (MWNTs) enables paramagnetic nanotubes to be obtained by absorbing iron salts. Characterization of paramagnetic MWNTs was performed with TEM, FTIR, DSC, and VSM. Paramagnetic CNTs are used for the purification of water from heavy metals and plastic originated compounds. Most of the PVC-based materials contain phthalate acid esters (PAE) which have considerable effects on human health. In this study, MWNTs were used for removing diethyl phthalate (DEP) from methanol after their toxicity evaluation. Concentration-dependent absorption of 494, 1461, and 2950 ppm, respectively, were measured from the mixture containing 13.3, 33.3, and 66.6% DEP in 40 mg paramagnetic MWNT solution. Although it was concluded that magnetic nanotubes would exhibit significant toxic effects compared to untreated MWNTs, GC-MS results were showed a reliable absorption capacity of magnetic nanotubes for purification applications. The results demonstrated that the use of magnetic MWNTs for the extraction of PAEs is an efficient way from liquids.

Advanced Development of Carboxylic Acid Functionalized Multiwall Carbon Nanotubes as Safe Inhalation Drug Carrier

Background: Multiwall Carbon Nanotubes (MWCNTs) have innovative characteristic features strongly associated with nanotechnology and drug delivery applications. Objectives: The current work was performed with an objective to assess the inhalation toxicity of multi-walled carbon nanotubes. Methods: Functionalization of multi-walled carbon nanotubes was carried out by the initial basic treatment with hydrochloric acid and nearly assessed by Infrared (IR) spectroscopy, mass spectroscopy, and Transmission electron microscopy (TEM) in comparison with pure multi-walled carbon nanotubes. The acute inhalation toxicity of these functionalized and pure multi-walled carbon nanotubes was assessed in Wistar rats. The parameters: hematology, liver function test, kidney function test, and histopathology observed, evaluated and interpreted for the toxicity study. Results: The functionalized multi-walled carbon nanotubes and pure multi-walled carbon nanotubes were nearly assessed by IR spectroscopy, mass spectroscopy, and TEM. The assessments affirmed and anticipated that the pure multi-walled carbon nanotube undergoes successful functionalization. Results obtained showed a remarkable difference in the ranges of hemoglobin and platelet. The acute inhalation toxicity study did not show any toxicity of functionalized multi-walled carbon nanotubes when compared to pure multi-walled carbon nanotubes. The results of acute inhalation toxicity studies did not show any significant changes also not demonstrated hazard potential in rats following acute exposures to the functionalized multi-walled carbon nanotubes and there is no significant toxicity. Because of basic treatment during functionalization all impurity gets removed. During functionalization addition of oxygen containing group and removal of carbon dioxide group occurs. Conclusion: Functionalized multi-walled carbon nanotubes can prove to be a novel, safe, and non-toxic carrier for the delivery of drugs by inhalation route.

Chronic toxicity of Multi-walled carbon nanotubes in human pleural mesothelial cells

Objective: To explore the chronic toxicity and its potential mechanism of multi-walled carbon nanotube (MWCNT) in human pleural mesothelial cells. Methods: A sustainable exposure of MeT-5A cells to MWCNT at 10 μg/cm(2) for one year was conducted in 2016. During the exposure, the cell images and cell proliferation was recorded every 4 weeks. The cell apoptosis, cell cycle, cell migration and cell invasion were compared between the control cells and the cells after MWCNT exposure. Finally, the gene expression was screened with Affymetrix clariom D assay, and some of the significantly differential expressed genes was verified by RT-PCR. Results: Compared with the control group, the proliferation ability of the cells in the 1-year exposed group was significantly increased, and the rate of proliferation was about 2-3 times as that in the Control Group (F=481.32, P<0.05) . MeT-5A cells all showed cell cycle arrest effect, which showed the increase of G1 phase and the decrease of s phase and G2 phase (F=14.94, P<0.05) . The apoptosis rate of cells in the treated group was significantly higher than that in the control group after 6 months (F=15.12, P<0.05) , but the early apoptosis rate and the total apoptosis rate of cells in the treated group were not significantly different from those in the control group after 1 year (F=3.97, P<0.05) . The cell migration and invasion were both promoted by MWCNT. Furthermore, the differentially expressed genes was screened, to find 2, 878 genes with more than 2 folds changes. To further verified, RT-PCR was conducted with PIK3R3、WNT2B、VANGL2、ANXA1, and their expression changes were consistent with above. Conclusion: MWCNT might have a carcinogenic potential to MeT-5A cells after the long term exposure.

Apigenin ameliorates oxidative stress and mitochondrial damage induced by multiwall carbon nanotubes in rat kidney mitochondria.

The toxicity of carbon nanotubes (CNTs) toward the mitochondria of the kidney is not fully recognized and still needs further research. Apigenin (APG) is known as a flavonoid compound and natural antioxidant. The purpose of this study was to assess the ameliorative role of APG against multiwall CNT(MWCNT)-induced kidney toxicity in rats. The animals were administrated with APG (10 mg/kg) for 2 weeks and then were exposed to MWCNTs (5 mg/m3 ) in pure and impure forms (10 and 100 nm) for 5 h/dayand 5 days/week. Then, mitochondria were isolated from the kidney tissue and mitochondrial toxicity parameters were measured. Decreases in succinate dehydrogenaseactivity have been reported in all groups exposed to MWCNTs. Results indicated that MWCNTs in both forms and sizes were able to increase the generation of reactive oxygen species, decline mitochondrial membrane potential, induce mitochondrial swelling, and release cytochrome c in isolated kidney mitochondria. The pretreatment of APG decreased all the abovementioned mitochondrial damage and oxidative stress parameters induced by both pure and impure MWCNTs. Our results showed that MWCNTs have the ability to enter the body, subsequently, cross cellular barriers, and reach the kidney as a sensitive organ, which can resultin mitochondrial damage in kidney cells including renal tubular cells. In addition, APG can be an effective nutritional antioxidant regimen against MWCNT-induced kidney damage.

Slime molds response to carbon nanotubes exposure: from internalization to behavior

Carbon nanotubes (CNTs) offer attractive opportunities due to their physical, electrical, mechanical, optical, and thermal properties. They are used in a wide range of applications and are found in numerous consumer products. On the downside, their increasing presence in the environment poses potential threats to living organisms and ecosystems. The aim of this study was to evaluate the toxicity of double-walled carbon nanotubes (DWCNTs) on a new model system: the acellular slime mold Physarum polycephalum. Despite its ecological significance, its simplicity of organization, and its behavioral complexity, exposure of such organisms to nanoparticles has been poorly investigated. Slime molds were exposed to DWCNTs using three routes of exposure (topical, food, environment). We first demonstrated that DWCNTs were rapidly internalized by slime molds especially when DWCNTs were mixed with the food or spread out in the environment. Secondly, we showed that a 6-week exposure to DWCNTs did not lead to bioaccumulation nor did it lead to persistence in the slime molds when they entered a resting stage. Thirdly, we revealed that 2 days following exposure, DWCNTs were almost entirely excreted from the slime molds. Lastly, we uncovered that DWCNTs exposure altered the migration speed, the pseudopods formation, and the expansion rate of the slime molds. Our results extend our current knowledge of CNTs cytotoxicity and introduce P. polycephalum as an ideal organism for nanotoxicology.

Toxicity and environmental impact of multi-walled carbon nanotubes to nitrogen-fixing bacterium Azotobacter chroococcum

With the large-scale production and wide applications of carbon nanotubes (CNTs), they are inevitably entering the environment and bringing unknown threats to environmental organisms. Nitrogen-fixing bacteria dominate 80% of the nitrogen fixation in nitrogen cycle. Herein, we investigated the toxicity and environmental impact of multi-walled CNTs (MWCNTs) to nitrogen-fixing bacterium Azotobacter chroococcum. MWCNTs slightly inhibited the growth of A. chroococcum and induced small increase of death rate at high concentrations. MWCNTs did not penetrate the cell walls of A. chroococcum and no cytoplasm loss was observed. MWCNTs were only observed surrounding the A. chroococcum cells. According to oxidative stress assays, MWCNTs induced meaningful oxidative damage at 0.5 mg/mL after 6 d exposure, but the oxidative damage diminished at 14 d. MWCNTs did not affect the nitrogen fixation activity of A. chroococcum and the soil nitrogen contents. Our findings provided the fundamental data for the environmental safety of CNTs to nitrogen-fixing bacteria.

Carbon nanotubes: A review on risks assessment, mechanism of toxicity and future directives to prevent health implication

Carbon nanotubes (CNTs) have tremendous applications in almost every walk of life; however, their harmful impacts on humans and the environment are not well addressed. CNTs have been used in various applications ranging from medical science to different engineering branches, to ease human life. Generally, the toxicological profile of CNTs under laboratory conditions cannot be assessed primarily in medical science due to the inconsistent availability of cytotoxic study data. CNT toxicity has been affected by many physicochemical properties (e.g., size, type of functionalization), concentration, the extent of exposure, mode of exposure, and even the solvents/medium used to dissolve/disperse CNTs for their application. These inconsistencies arise due to the variation in synthesis methods as well as the mode of their human exposure. Besides their unlimited use in various fields, most of CNT toxicity aspects and mechanisms remain uncertain. Additionally, in-depth knowledge of CNTs toxicity is scarce, and the available literature shows dissimilarities in experimental data and exposure studies. To understand the toxicological issues, it is the need of the hour to provide insight into the published data, post-exposure studies, and various factors that may damage the cells due to CNTs toxicity. This review article analyses the hazardous potential through toxicological implications and summarizes the detailed mechanism(s) of CNTs studied on the different model organisms, including human cell lines. In this review article, we hypothesized that thorough knowledge of various aspects, as mentioned above, helps us design and develop possible strategies to reduce the toxicity of nanomaterial to make them safer and secure for humanity’s betterment.

Biomedical application of carbon nanotubes (CNTs) in vulnerable parts of the body and its toxicity study: A state-of-the-art-review

Carbon nanotubes are known for its distinctive, newer generation, unique materials for its appealing properties. They have excellent high surface area, high biocompatibility, and flexibility, electrical, mechanical and thermal properties which can be customized and functionalized on the basis of the materials. The use of such materials in biomedical field is on demand. The application of carbon nanotubes in biomedicines has been saving the lives of human race. When CNTs merged with organic materials developed better alternative in the field of biomedicines. In present review the applications of carbon nanotubes in biomedical field has been discussed with special references to sensitive area of the body. These diagnostic applications cover nervous tissue regeneration, neural scaffolds, Myocardial Conduction, and tissue engineering, cancer treatment etc. Toxicities of CNTs and factors effective to carbon nanotube applications were discussed in the review.

Assessment of the Skin and Heart Tissue Damage Following Inhalation of Carbon Nanotubes in Wistar Rats Using Isolated Mitochondria

The unique properties of carbon nanotubes (CNTs) have led to their use in various fields. But, the toxicity of CNTs has been reported in biological and environmental systems. The aim of this research is to study the effect of multi-wall carbon nanotubes (MWCNTs) through inhalation chamber on the mitochondrial damage and oxidative stress using the mitochondria obtained from the skin and heart. Rats were exposed to 5 mg/m3 of MWCNTs (10 nm) aerosol for 5 hours /day, 5 days/week for 2 weeks in a whole-body exposure chamber. After 2-weeks exposure, Heart and skin mitochondria were evaluated for evaluation of toxicity parameters. The results showed that nanoparticles significantly decreased mitochondrial succinate dehydrogenase (SDH) activity and increased the level of reactive oxygen species (ROS), collapse in mitochondria membrane potential (MMP), swelling in mitochondria, and cytochrome release. In conclusion, we suggested that 5 mg/m3 of MWCNTs (10 nm) induce ROS mediated cytotoxicity by directly targeting mitochondria in both skin and heart tissue.

Toxicity of poly-dispersed single-walled carbon nanotubes on bone marrow derived Hematopoietic Stem and Progenitor Cells

This study has explored the effect of acid-functionalized single-walled carbon nanotubes (AF-SWCNTs) on Hematopoietic Stem and Progenitor Cell (HSPCs) in mouse bone marrow. Administration of AF-SWCNTs induced a significant decline in the live-cell recovery from bone marrow. Lin-negative Stem cell enriched HSPCs internalized AF-SWCNTs that remained localized in cytoplasmic areas. Incubation of HSPCs with AF-SWCNTs resulted in induction of cell death, inhibition of cell cycle, and induction of reactive oxygen species (ROS) as well as the expression of Caspase 3, 7 and 9 enzymes. In vitro culture with a cytokine cocktail (SCF, GM-CSF, IL3, IL6, IL7) induced differentiation of HSPCs into lymphocytes and myeloid cells, that was inhibited in presence of AF-SWCNTs. Relative recoveries of lymphocytes specifically B lymphocytes, was significantly reduced by AF-SWCNT-treatment, whereas the relative recovery of myeloid cells remained unaltered. These results suggest that AF-SWCNTs have significant toxic effects on HSPCs and differentially suppress the ontogeny of lymphoid and myeloid cells.

Organ Specific Toxicity of Single and Multi-Walled Carbon Nanotubes: A Review

Carbon nanotubes are one of the most widely investigated carbon structures because of variety of physicochemical features offered by them. Their dimensions, surface chemistry and functionalization opportunities make them exceptional carrier for targeted drug delivery gene therapy, diagnosis and cell imaging. Both single and multi-walled CNTs have been functionalized for therapeutic applications. However, these structures have been associated with potential in vitro and in vivo cytotoxic effects. Such toxicities have been described to involve both cellular and subcellular mechanisms. Major organs that have shown significant CNTs related toxic effects include lungs, brain, heart, kidney, liver and skin. This review focuses on the potential toxicological effects of single and multi-walled carbon nanotubes and functionalization on these organs and associated mechanisms of toxicity

Antimicrobial and anti-adhesive properties of carbon nanotube-based surfaces for medical applications: a systematic review.

SummaryAlthough high-performance carbon materials are widely used in surface engineering, with emphasis on carbon nanotubes (CNTs), the application of CNT nanocomposites on medical surfaces is poorly documented. In this study, we aimed to evaluate the antimicrobial and anti-adhesive properties of CNT-based surfaces. For this purpose, a PRISMA-oriented systematic review was conducted based on predefined criteria and 59 studies were selected for the qualitative analysis. Results from the analyzed studies suggest that surfaces containing modified CNTs, and specially CNTs conjugated with different polymers, exhibited strong antimicrobial and anti-adhesive activities. These composites seem to preserve the CNT toxicity to microorganisms and promote CNT-cell interactions, as well as to protect them from nonspecific protein adsorption. However, CNTs cannot yet compete with the conventional strategies to fight biofilms as their toxicity profile on the human body has not been thoroughly addressed. This review can be helpful for the development of new engineered medical surfaces.