Nanomaterials

Our medical research library holds 12 studies published in Nanomaterials (2019–2026). Each entry links to the study's record on PubMed and, where there is one, to the publisher's page and a free full text. 12 have an abstract, the authors' own summary as PubMed records it: open "Abstract" to read it.

About the journal

• Publisher: MDPI AG
• Published: 2010 to the present, Switzerland
• Language: English
• ISSN: 2079-4991 (electronic)
• Its record in the NLM Catalog

2020s

• Dose-Response Relationships for Lung Tumor and Pleural Mesothelioma Induction by Repetitive Intratracheal Instillation of a Multiwalled Carbon Nanotube, MWCNT-7, in Rats: Comparison with Inhalation Carcinogenicity Based on Lung Burden. A. Maeno, M. Hojo, Y. Sakamoto, et al. 2026;16(16). PubMed · Publisher · Free full text

  Abstract

  The multiwalled carbon nanotube, MWCNT-7, is carcinogenic to rat lungs when inhaled over the course of 2 years, but does not induce pleural mesothelioma. In contrast, intratracheal instillation of MWCNT-7 causes both lung tumors and pleural mesotheliomas. To explore the possibility of the use of the intratracheal instillation technique in risk characterization, we administered this widely used reference material using instillation to male F344 rats at doses of 0.0175, 0.07, 0.28, or 0.42 mg/kg once per week for 13 weeks, followed by an observation period of 91 weeks and compared the dose-response toxicological data with the 2-year inhalation study. Lung tumors and pleural mesotheliomas were induced in a dose-dependent manner (the 0.42 mg/kg group was excluded from analysis of lung tumor formation). The lung burden of MWCNT-7 at week 13 was dose-dependent: 0.0302, 0.191, 0.98, and 1.369 mg/lung in the 0.0175, 0.07, 0.28, and 0.42 mg/kg groups, respectively. The number of fibers in the pleural lavage fluid was also dose-dependent. The no-observed-adverse-effect-level (NOAEL) of MWCNT-7's carcinogenicity was 0.0302 mg/lung based on no significant lung tumor induction and no mesothelioma induction in the 0.0175 mg/kg group. When compared based on lung burden, the dose-response relationship and NOAEL of lung tumor induction resembled those in the 2-year inhalation study, offering the possibility of the application of this protocol for risk characterization.

• Comparative Carcinogenicity of Double-Walled Carbon Nanotubes of Different Lengths Administered by Intratracheal Installation into Rat Lungs. O.H.M. Ahmed, D.M. Saleh, W.T. Alexander, et al. 2025;15(18). PubMed · Publisher · Free full text

  Abstract

  We previously carried out an in vivo 2-year study to assess the potential toxicity/carcinogenicity of double-walled carbon nanotubes (DWCNTs) in a rat lung. We found that administration of DWCNTs by intratracheal-intrapulmonary spraying (TIPS) at a dose of 0.5 mg/rat induced the development of lung tumors in 7 of 24 treated rats while 1 of 21 untreated rats and 1 of 25 vehicle treated rats developed lung tumors. In the current study, we administered DWCNTs of different lengths, 1.5 µm, 7 µm, and 15 µm, to rats by TIPS to investigate the possible effect of the length of this thin, flexible CNT on toxicity/carcinogenicity in rat lungs. Rats were administered DWCNTs with lengths of 1.5 µm (D1.5), 7 µm (D7), and 15 µm (D15) by TIPS once every other day over the course of two weeks for a total of eight administrations. The total dose administered was approximately 22 × 1012 fibers per rat, corresponding to 0.0504 mg for D1.5, 0.232 mg for D7, and 0.504 mg for D15. Another group of rats was administered 0.5 mg MWCNT-7, a known carcinogen. Animals were killed at weeks 6 and 104 (4 and 102 weeks after the final TIPS administration). The mean survival time of the rats in the untreated, vehicle, D1.5, D7, and D15 groups was 99 to 104 weeks. One rat in the D1.5 group and one rat in the D15 group died before week 75. The remaining rats in the untreated, vehicle, D1.5, D7, and D15 groups were included in the final assessment of lung toxicity/carcinogenicity. In contrast, 11 rats in the MWCNT-7 group died before week 75 due to the development of malignant mesothelioma. Due to the much shorter survival time of the rats treated with MWCNT-7, accurate assessment of lung proliferative lesions in this group was not possible. At week 6, an increase in alveolar macrophages and granulation tissue foci in the alveoli was observed in all DWCNT administered groups. The alveolar epithelial cell PCNA index was also significantly increased in the D7 and D15 groups. Increases in alveolar macrophages, granulation tissue foci, and the alveolar epithelial cell PCNA index were observed in all DWCNT-treated groups at the final sacrifice. The incidences of lung tumors were 0/13, 0/12, 4/12, 3/8, and 2/10 in the untreated, vehicle, D1.5, D7, and D15 groups, respectively. In agreement with our previous study, the DWCNTs tested in the present study were carcinogenic in the rat lung. In addition, we present evidence that DWCNT fiber length may possibly have an effect on DWCNT-induced carcinogenicity in rat lungs.

• Comparative Gene Expression Analysis of Malignant Mesothelioma and Lung Adenocarcinomas Induced by Multi-Walled Carbon Nanotube-7 and Double-Walled Carbon Nanotubes in Rats: Distinct Molecular Signatures and Canonical Pathways. M. Gi, S. Suzuki, D.M. Saleh, et al. 2025;15(23). PubMed · Publisher · Free full text

  Abstract

  Although numerous experimental studies have demonstrated the carcinogenic potential of multi-walled carbon nanotubes (MWCNTs) in lungs, the underlying molecular mechanisms-especially gene expression changes associated with different tumor types-remain poorly characterized. To elucidate the molecular signatures associated with MWCNT-induced carcinogenesis, we performed microarray-based gene expression profiling of rat lung tumors induced by MWCNT-7, including both adenocarcinoma (ADC) and malignant mesothelioma (MM), as well as ADCs induced by two types of double-walled CNTs (DWCNTs) differing in fiber length (1.5 µm and 7 µm). Hierarchical clustering revealed that the MWCNT-7-induced MM exhibited a gene expression profile distinct from the ADCs. The ADCs induced by the DWCNTs and the ADC induced by MWCNT-7 shared several pathways that were distinct from those of the MWCNT-7 induced MM. The distinct pathways upregulated in the ADCs versus the MM support the conclusion that MWCNT-induced ADCs arise through distinct biological mechanisms compared to MWCNT-induced MMs and identified tumor-type-specific biomarker candidates: complement factor I (CFI) and secreted phosphoprotein 1 (SPP1) for ADCs, and fibronectin 1 (FN1) for MM. In addition, the gene expression profiles of the ADCs induced by the three fiber types indicate that both types of thin flexible DWCNTs used in the present study promoted a number of carcinogenic pathways in the rat lung that were also promoted by MWCNT-7, which is a class 2B carcinogen. These results support the conclusion that DWCNTs are carcinogenic in the rat lung and highlight the importance of further assessments of the potential lung carcinogenicity of inhaled thin flexible CNTs.

• Comparison of Lung Inflammatory and Transcriptional Responses in Mice and Rats Following Pulmonary Exposure to a Fiber Paradigm-Compatible and Non-Compatible MWCNT. L.A. Saarimäki, P.H. Danielsen, K.B. Knudsen, et al. 2025;15(17). PubMed · Publisher · Free full text

  Abstract

  Inhalation of multi-walled carbon nanotubes (MWCNTs) poses potential health risks due to their structural similarity to asbestos and their ability to induce chronic lung inflammation, fibrosis, and lung cancer in animal models. This study investigated the pulmonary inflammatory and transcriptomic responses of two distinct MWCNTs-NM-401 (long, rigid) and NM-403 (short, thin)-in rats and mice using intratracheal instillation at matched dose levels at two post-exposure time points. Both MWCNTs induced acute neutrophilic inflammation and dose-dependent transcriptomic alterations in both species, with NM-403 eliciting a stronger response. Transcriptomic profiling revealed a substantial overlap in differentially expressed genes across materials and species, particularly at the early time point. Fibrosis-associated genes were upregulated in both species, with more persistent expression observed in rats. Acute phase response genes, including Orosomucoid 1 and Lipocalin 2 were commonly induced, while Serum Amyloid A3 and Orosomucoid 2 were selectively upregulated in mice. Functional enrichment analyses showed conserved activation of immune and inflammatory pathways. Our findings show that even short, non-fiber-like MWCNTs can provoke potent and persistent pulmonary effects, challenging assumptions based solely on MWCNT properties. Despite differences in long-term responses, the overall inflammatory and transcriptional profiles showed strong interspecies concordance, suggesting that both rats and mice are relevant models for assessing MWCNT-induced pulmonary toxicity.

• Dissolution Reaction and Surface Modification of UICC Amosite in Mimicked Gamble's Solution: A Step towards Filling the Gap between Asbestos Toxicity and Its Crystal Chemical Features. A. Pacella, P. Ballirano, M.C. Di Carlo, et al. 2023;13(22). PubMed · Publisher · Free full text

  Abstract

  This study focuses on the dissolution process and surface characterization of amosite fibres following interaction with a mimicked Gamble's solution at a pH of 4.5 and T = 37 °C, up to 720 h. To achieve this, a multi-analytical approach was adopted, and the results were compared to those previously obtained on a sample of asbestos tremolite and UICC crocidolite, which were investigated under the same experimental conditions. Combining surface chemical data obtained by XPS with cation release quantified by ICP-OES, an incongruent behaviour of the fibre dissolution was highlighted for amosite fibres, similarly to asbestos tremolite and UICC crocidolite. In particular, a preferential release of Mg and Ca from the amphibole structure was observed, in agreement with their Madelung site energies. Notably, no Fe release from amosite fibres was detected in our experimental conditions (pH of 4.5 and atmospheric pO2), despite the occurrence of Fe(II) at the M(4) site of the amphibole structure, where cations are expected to be rapidly leached out during mineral dissolution. Moreover, the oxidation of both the Fe centres initially present on the fibre surface and those promoted from the bulk, because of the erosion of the outmost layers, was observed. Since biodurability (i.e., the resistance to dissolution) is one of the most important toxicity parameters, the knowledge of the surface alteration of asbestos possibly occurring in vivo may help to understand the mechanisms at the basis of its long-term toxicity.

• Synthesis of Ni-Doped Tremolite Fibers to Help Clarify the Aetiology of the Cytotoxic Outcome of Asbestos. A. Bloise, E. Giorno, D. Miriello, et al. 2023;13(8). PubMed · Publisher · Free full text

  Abstract

  Asbestos fibers act as complex crystal-chemical reservoirs susceptible of releasing potentially toxic elements (such as ions impurities) into the lung cellular environment during permanency and dissolution. To comprehend the exact pathological mechanisms that are triggered upon inhalation of asbestos fibers, in vitro studies on possible interactions between the mineral and the biological system have been carried out mostly by using natural asbestos. However, this latter comprises intrinsic impurities such as Fe2+/Fe3+ and Ni2+ ions, and other eventual traces of metallic pathogens. Furthermore, often, natural asbestos is characterized by the co-presence of several mineral phases, fiber dimensions of which are randomly distributed in width and in length. For these reasons, it is albeit challenging to precisely identify toxicity factors and to define the accurate role of each factor in the overall pathogenesis of asbestos. In this regard, the availability of synthetic asbestos fibers with accurate chemical composition and specific dimensions for in vitro screening tests would represent the perfect tool to correlate asbestos toxicity to its chemico-physical features. Herein, to palliate such drawbacks of natural asbestos, well-defined Ni-doped tremolite fibers were chemically synthesized in order to offer biologists adequate samples for testing the specific role of Ni2+ in asbestos toxicity. The experimental conditions (temperature, pressure, reaction time and water amount) were optimized to produce batches of asbestos fibers of the tremolite phase, with uniformly distributed shape and dimensions and a controlled content of Ni2+ metal ions.

• Do Carbon Nanotubes and Asbestos Fibers Exhibit Common Toxicity Mechanisms?. S.S. Gupta, K.P. Singh, S. Gupta, et al. 2022;12(10). Review PubMed · Publisher · Free full text

  Abstract

  During the last two decades several nanoscale materials were engineered for industrial and medical applications. Among them carbon nanotubes (CNTs) are the most exploited nanomaterials with global production of around 1000 tons/year. Besides several commercial benefits of CNTs, the fiber-like structures and their bio-persistency in lung tissues raise serious concerns about the possible adverse human health effects resembling those of asbestos fibers. In this review, we present a comparative analysis between CNTs and asbestos fibers using the following four parameters: (1) fibrous needle-like shape, (2) bio-persistent nature, (3) high surface to volume ratio and (4) capacity to adsorb toxicants/pollutants on the surface. We also compare mechanisms underlying the toxicity caused by certain diameters and lengths of CNTs and asbestos fibers using downstream pathways associated with altered gene expression data from both asbestos and CNT exposure. Our results suggest that indeed certain types of CNTs are emulating asbestos fiber as far as associated toxicity is concerned.

• Occupational Exposure to Carbon Nanotubes and Carbon Nanofibres: More Than a Cobweb. E. Bergamaschi, G. Garzaro, G. Wilson Jones, et al. 2021;11(3). Review PubMed · Publisher · Free full text

  Abstract

  Carbon nanotubes (CNTs) and carbon nanofibers (CNFs) are erroneously considered as singular material entities. Instead, they should be regarded as a heterogeneous class of materials bearing different properties eliciting particular biological outcomes both in vitro and in vivo. Given the pace at which the industrial production of CNTs/CNFs is increasing, it is becoming of utmost importance to acquire comprehensive knowledge regarding their biological activity and their hazardous effects in humans. Animal studies carried out by inhalation showed that some CNTs/CNFs species can cause deleterious effects such as inflammation and lung tissue remodeling. Their physico-chemical properties, biological behavior and biopersistence make them similar to asbestos fibers. Human studies suggest some mild effects in workers handling CNTs/CNFs. However, owing to their cross-sectional design, researchers have been as yet unable to firmly demonstrate a causal relationship between such an exposure and the observed effects. Estimation of acceptable exposure levels should warrant a proper risk management. The aim of this review is to challenge the conception of CNTs/CNFs as a single, unified material entity and prompt the establishment of standardized hazard and exposure assessment methodologies able to properly feed risk assessment and management frameworks.

• Biocompatibility and Carcinogenicity of Carbon Nanotubes as Biomaterials. K. Aoki, N. Saito. 2020;10(2). Review PubMed · Publisher · Free full text

  Abstract

  With the development of nanotechnology in recent years, there have been concerns about the health effects of nanoparticles. Carbon nanotubes (CNTs) are fibrous nanoparticles with a micro-sized length and nano-sized diameter, which exhibit excellent physical properties and are widely studied for their potential application in medicine. However, asbestos has been historically shown to cause pleural malignant mesothelioma and lung cancer by inhalation exposure. Because carbon nanotubes are also fibrous nanotubes, some have raised concerns about its possible carcinogenicity. We have reported that there is no clear evidence of carcinogenicity by local and intravenous administration of multi-walled CNTs to cancer mice models. We firmly believe that CNTs can be a safe, new, and high-performance biomaterials by controlling its type, site of administration, and dosage.

• Three-Year Study of Markers of Oxidative Stress in Exhaled Breath Condensate in Workers Producing Nanocomposites, Extended by Plasma and Urine Analysis in Last Two Years. D. Pelclova, V. Zdimal, M. Komarc, et al. 2020;10(12). PubMed · Publisher · Free full text

  Abstract

  Human data concerning exposure to nanoparticles are very limited, and biomarkers for monitoring exposure are urgently needed. In a follow-up of a 2016 study in a nanocomposites plant, in which only exhaled breath condensate (EBC) was examined, eight markers of oxidative stress were analyzed in three bodily fluids, i.e., EBC, plasma and urine, in both pre-shift and post-shift samples in 2017 and 2018. Aerosol exposures were monitored. Mass concentration in 2017 was 0.351 mg/m3 during machining, and 0.179 and 0.217 mg/m3 during machining and welding, respectively, in 2018. In number concentrations, nanoparticles formed 96%, 90% and 59%, respectively. In both years, pre-shift elevations of 50.0% in EBC, 37.5% in plasma and 6.25% in urine biomarkers were observed. Post-shift elevation reached 62.5% in EBC, 68.8% in plasma and 18.8% in urine samples. The same trend was observed in all biological fluids. Individual factors were responsible for the elevation of control subjects' afternoon vs. morning markers in 2018; all were significantly lower compared to those of workers. Malondialdehyde levels were always acutely shifted, and 8-hydroxy-2-deoxyguanosine levels best showed chronic exposure effect. EBC and plasma analysis appear to be the ideal fluids for bio-monitoring of oxidative stress arising from engineered nanomaterials. Potential late effects need to be targeted and prevented, as there is a similarity of EBC findings in patients with silicosis and asbestosis.

2010s

• Critical Admission Temperature of H₂ and CH₄ in Nanopores of Exchanged ERI Zeolites. K. Quiroz-Estrada, M.Á. Hernández, C. Felipe-Mendoza, et al. 2019;9(2). PubMed · Publisher · Free full text

  Abstract

  Due to the nanoporous nature of zeolitic materials, they can be used as gas adsorbents. This paper describes the effect of critical admission temperature through narrow pores of natural ERI zeolites at low levels of coverage. This phenomenon occurs by adsorption of CH₄ and H₂ on pores in natural erionite. The zeolite was exchanged with aqueous solutions of Na⁺, Mg2+, and Ca2+ salts at different concentrations, times, and temperatures of treatment. Experimental data of CH₄ and H₂ adsorption were treated by the Langmuir equation. Complementarily, the degree of interaction of these gases with these zeolites was evaluated by the evolution of isosteric heats of adsorption. The Ca2+ and Mg2+ cations favor the adsorption phenomena of H₂ and CH₄. These cations occupy sites in strategic positions Ca1, Ca2, and Ca3, which are located in the nanocavities of erionite zeolites and K2 in the center of 8MR. Following the conditions of temperature and the exchange treatment, ERICa2 and ERINa3 samples showed the best behavior for CH₄ and H₂ adsorption.

• Risk Analysis of Cellulose Nanomaterials by Inhalation: Current State of Science. J.D. Ede, K.J. Ong, M. Goergen, et al. 2019;9(3). Review PubMed · Publisher · Free full text

  Abstract

  Cellulose nanomaterials (CNs) are emerging advanced materials with many unique properties and growing commercial significance. A life-cycle risk assessment and environmental health and safety roadmap identified potential risks from inhalation of powdered CNs in the workplace as a key gap in our understanding of safety and recommended addressing this data gap to advance the safe and successful commercialization of these materials. Here, we (i) summarize the currently available published literature for its contribution to our current understanding of CN inhalation hazard and (ii) evaluate the quality of the studies for risk assessment purposes using published study evaluation tools for nanomaterials to assess the weight of evidence provided. Our analysis found that the quality of the available studies is generally inadequate for risk assessment purposes but is improving over time. There have been some advances in knowledge about the effects of short-term inhalation exposures of CN. The most recent in vivo studies suggest that short-term exposure to CNs results in transient inflammation, similarly to other poorly soluble, low toxicity dusts such as conventional cellulose, but is markedly different from fibers with known toxicity such as certain types of multiwalled carbon nanotubes or asbestos. However, several data gaps remain, and there is still a lack of understanding of the effects from long-term, low-dose exposures that represent realistic workplace conditions, essential for a quantitative assessment of potential health risk. Therefore, taking precautions when handling dry forms of CNs to avoid dust inhalation exposure is warranted.

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