Nanotechnology in respiratory medicine
© Omlor et al. 2015
Received: 27 January 2015
Accepted: 20 May 2015
Published: 29 May 2015
Like two sides of the same coin, nanotechnology can be both boon and bane for respiratory medicine. Nanomaterials open new ways in diagnostics and treatment of lung diseases. Nanoparticle based drug delivery systems can help against diseases such as lung cancer, tuberculosis, and pulmonary fibrosis. Moreover, nanoparticles can be loaded with DNA and act as vectors for gene therapy in diseases like cystic fibrosis. Even lung diagnostics with computer tomography (CT) or magnetic resonance imaging (MRI) profits from new nanoparticle based contrast agents. However, the risks of nanotechnology also have to be taken into consideration as engineered nanomaterials resemble natural fine dusts and fibers, which are known to be harmful for the respiratory system in many cases. Recent studies have shown that nanoparticles in the respiratory tract can influence the immune system, can create oxidative stress and even cause genotoxicity. Another important aspect to assess the safety of nanotechnology based products is the absorption of nanoparticles. It was demonstrated that the amount of pulmonary nanoparticle uptake not only depends on physical and chemical nanoparticle characteristics but also on the health status of the organism. The huge diversity in nanotechnology could revolutionize medicine but makes safety assessment a challenging task.
KeywordsNanoparticles Lung Airways Nanotoxicology Biodistribution Nanomedicine
Applications of nanotechnology in therapeutics and diagnostics
Although clinical application of nanotechnology in therapeutics and diagnostics is still rare, there are multiple promising candidates for future use in the field of respiratory medicine.
Nanoparticle based drug delivery also offers potential in other fields of respiratory medicine. In experiments with tuberculosis infected guinea pigs, it was demonstrated that inhaled alginate nanoparticles encapsulating isoniazid, rifampicin, and pyrazinamide showed better bioavailability and higher efficiency than oral drug medication . Similar results were presented by Pandey et al. with the three antitubercular drugs encapsulated in poly (DL-lactide-co-glycolide) nanoparticles . Moreover, another study demonstrated that pirfenidone loaded nanoparticles have higher anti-fibrotic efficacy in the treatment of mice with bleomycin-induced pulmonary fibrosis than dissolved pirfenidone .
Like viruses, nanoparticles can be used as vectors for genes. But in contrast to viruses, they are less immunogenic and have higher DNA transport capacity. In a study, DNA loaded polyethylenimine nanoparticles were used in order to treat lipopolysaccharide induced acute lung injury in mice. After intravenous injection of the nanoparticles, the beta2-Adrenic Receptor genes in the nanoparticles led to a short lived transgene expression in alveolar epithelia cells. As a result the 5-day survival rate improved from 28 % to 64 %. The severity of the symptoms measured by alveolar fluid clearance, lung water content, histopathology, bronchioalveolar lavage cellularity, protein concentration, and inflammatory cytokines was also significantly attenuated . DNA loaded nanoparticles are also promising candidates in the treatment of cystic fibrosis. It was shown in a clinical trial that nasal application of DNA nanoparticles is safe and evidently leads to vector gene transfer . One major problem in this context is to overcome the mucus barrier. In a recent study, it was demonstrated that densely PEG-coated DNA nanoparticles can rapidly penetrate extracorporeal human cystic fibrosis and extracorporeal mouse airway mucus. In addition, those particles exhibited better gene transfer after intranasal administration to mice than conventional carriers .
Nanoparticles have the potential to improve pulmonary x-ray diagnostics. Folic acid-modified dendrimer-entrapped gold nanoparticles were utilized as imaging probes for targeted CT imaging. In in-vitro and in-vivo tests, the nanoparticles were trapped in the lysosomes of folic acid receptor expressing lung adenocarcinoma cells (SPC-A1). It was possible to detect the tumor cells by micro-CT imaging after nanoparticle uptake. In addition, it was also shown that the particles possess good biocompatibility, with no impact on cell morphology, viability, cell cycle, and apoptosis . Nanoparticles can also be used to enhance MR diagnostics of lung tissue. In experiments with intratracheal administration of Gadolinium-DOTA nanoparticles in mice, signal enhancements in several organs including the lung were measured with ultrashort-echo-time-proton-MRI. The signal change over time in the different organs demonstrated the passage of the nanoparticles from the lung to the blood, then to the kidneys, and finally to the bladder .
Toxicological aspects of nanomaterials
Toxic effects of nanoparticles are a major concern in pulmonary medicine. Especially ultrafine particles of low soluble, low toxic materials like titanium dioxide, carbon black, and polystyrene are overall more toxic and inflammatory than fine particles of the same material. This applies to both synthesized nanoparticles and natural dusts . For nano related toxicity multiple mechanisms seem to be important. In the following, the interaction with the immune system, the creation of oxidative stress, and toxic effects on the genome are taken a closer look at. In order to correlate toxic effects with nanoparticle properties, it is necessary to thoroughly characterize the selected nanoparticles prior to administration.
The most commonly used methods to characterize nanoparticles for toxicology studies are transmission electron microscopy (TEM) for size, morphology, and agglomeration, dynamic light scattering (DLS) for the size distribution of the particles, zeta potential measurement for nanoparticle surface charge, and x-ray diffraction (XRD) for the particles’ crystal structure. In some cases such as gold and silver nanoparticles, UV-vis spectroscopy can be used to determine size and size distribution due to a special size dependent optical activity . Ideally, nanoparticle characterization is repeated after administration as changes of the nanoparticles during the application process are possible. In in-vitro experiments, nanoparticles are usually applied by mixing with cell culture medium. The dissolved components of the medium, especially the ions, lead to agglomeration and precipitation of many nanoparticles, causing significant changes in their physicochemical properties. Similar effects are to be expected when nanoparticles come into contact with surfactant or other biological fluids. It was shown, that some nanoparticles tend to form protein coronae in biological systems .
Effects on immune system and inflammation
Oxidative stress and catalysis
Oxidative stress induction in respiratory tissue by different nanoparticles
(BEAS-2B and A549 lung cells)
(BEAS-2B and A549 lung cells)
Another important type of toxicity caused by nanoparticles is genotoxicity. A common method to quantify genotoxicity is the comet assay, which uses electrophoresis to detect DNA strand breaks. This assay was used in a recent study to check whether intratracheal instilled fullerene C60 nanoparticles induced DNA damage in male rats. However, despite inflammatory responses and hemorrhages in the alveoli of the C60 treated rats, there was no significant increase in fractured DNA in their lung cells. Therefore, it was concluded that even at inflammation inducing doses, fullerene C60 nanoparticles have no potential for DNA damage in the lung cells of rats . Similarly, another study demonstrated that intratracheal instillation of anatase TiO2 nanoparticles on rats did not result in genotoxicity. None of the TiO2 groups showed an increase in fractured DNA while the positive control with ethyl methanesulfonate exhibited significant increases . In contrast to those results, Kyjovska ZO et al. found that even in low doses, where no inflammation occurs, Printex 90 carbon black nanoparticles induce genotoxicity in mice. There was no inflammation, cell damage and acute phase response, which means that the increased DNA strand breaks are related to direct DNA damage caused by the nanoparticles . On the other hand, a recent study suggests that CeO2 nanoparticles may be even used as antioxidant and anti-genotoxic agents in the lung. After treatment with the oxidative stress-inducing agent KBrO3, BEAS-2B cells pretreated with the CeO2 nanoparticles showed significantly less intracellular ROS as well as a reduction in DNA damage compared to non-pretreated cells .
Research on the biodistribution of nanoparticles requires tracking of the applied nanoparticles in the test animal. Conventional light microscopy is not able to detect nanoparticles because of Abbe’s law. Therefore, electron microscopic imaging is often required. However, light microscopy can be used to describe the nanoparticle induced changes in the cell morphology without being able to see the nanoparticles themselves. Additionally, nanoparticles can be indirectly made detectable in light microscopy by a method called autometallography. This is a silver staining that can be used to increase the size of several types of nanoparticles like gold, silver, and some metal sulfides and selenides in the histological section . This technique was used to detect silver nanoparticles in the olfactory bulb and lateral brain ventricles of mice that had been intranasally treated with 25 nm silver nanoparticles .
Particle deposition and resorption in the respiratory tract
Over the last decade, major breakthroughs in nanotechnology have been achieved. It is only a matter of time before new nano based drugs reach respiratory medicine. Especially the fields of targeted drug delivery, gene therapy, and hyperthermia offer great potential for modern drugs. On the other hand the increased use of nanomaterials in all fields of life also bears the risk of exposure through inhalation. It is therefore essential to understand pulmonary toxicology of nanomaterials in all its facets. However, it is still very unclear why the toxic effects of nanoparticles in the respiratory tract are so inhomogeneous and not well predictable. In this context, not only local reactions of lung and airways but also nanoparticle uptake and distribution in the organism are important factors and therefore fields of current research. As only few nanoparticle compositions have been tested, it is questionable whether those results can be easily adapted to other nanoparticles. Because of the continuously increasing diversity of engineered nanoparticles, toxicology can hardly keep pace with the safety assessment of future products. Therefore, more attention should be set on this wide field of research.
Chitinase-3-like protein 1
Cationic shell-cross-linked knedel-like
Dynamic light scattering
Epidermal growth factor receptor
Enhanced permeability and retention
Magnetic resonance imaging
Non-small-cell lung carcinoma
Prostate-specific membrane antigen
Reactive oxygen species
Transmission electron microscopy
Tumor necrosis factor alpha
This work was supported by the foundation “Stiftung Bergmannshilfswerks Luisenthal” to Prof. Q.T. Dinh.
- Oberdorster G, Maynard A, Donaldson K, Castranova V, Fitzpatrick J, Ausman K, et al. Principles for characterizing the potential human health effects from exposure to nanomaterials: elements of a screening strategy. Part Fibre Toxicol. 2005;2:8.View ArticlePubMedPubMed CentralGoogle Scholar
- Nanotechnologies -- Terminology and definitions for nano-objects -- Nanoparticle, nanofibre and nanoplate, ISO/TS 27687:2008. [Accessed March 30, 2015]. Iso.org . 26-1-2012. Ref Type: Electronic Citation
- Grzelczak M, Vermant J, Furst EM, Liz-Marzan LM. Directed self-assembly of nanoparticles. ACS Nano. 2010;4:3591–605.View ArticlePubMedGoogle Scholar
- Hobbs SK, Monsky WL, Yuan F, Roberts WG, Griffith L, Torchilin VP, et al. Regulation of transport pathways in tumor vessels: role of tumor type and microenvironment. Proc Natl Acad Sci U S A. 1998;95:4607–12.View ArticlePubMedPubMed CentralGoogle Scholar
- Sanna V, Pala N, Sechi M. Targeted therapy using nanotechnology: focus on cancer. Int J Nanomedicine. 2014;9:467–83.PubMedPubMed CentralGoogle Scholar
- Ahn HK, Jung M, Sym SJ, Shin DB, Kang SM, Kyung SY, et al. A phase II trial of Cremorphor EL-free paclitaxel (Genexol-PM) and gemcitabine in patients with advanced non-small cell lung cancer. Cancer Chemother Pharmacol. 2014;74:277–82.View ArticlePubMedPubMed CentralGoogle Scholar
- Karra N, Nassar T, Ripin AN, Schwob O, Borlak J, Benita S. Antibody conjugated PLGA nanoparticles for targeted delivery of paclitaxel palmitate: efficacy and biofate in a lung cancer mouse model. Small. 2013;9:4221–36.View ArticlePubMedGoogle Scholar
- Yu B, Tai HC, Xue W, Lee LJ, Lee RJ. Receptor-targeted nanocarriers for therapeutic delivery to cancer. Mol Membr Biol. 2010;27:286–98.View ArticlePubMedPubMed CentralGoogle Scholar
- Libutti SK, Paciotti GF, Byrnes AA, Alexander Jr HR, Gannon WE, Walker M, et al. Phase I and pharmacokinetic studies of CYT-6091, a novel PEGylated colloidal gold-rhTNF nanomedicine. Clin Cancer Res. 2010;16:6139–49.View ArticlePubMedPubMed CentralGoogle Scholar
- Aurimmune CYT-6091 phase II clinical trial planned [Accessed March 30, 2015]. 17-9-2014. Ref Type: Online Source
- A Phase 2 Study to Determine the Safety and Efficacy of BIND-014 (Docetaxel Nanoparticles for Injectable Suspension) as Second-line Therapy to Patients With Non-Small Cell Lung Cancer. [Accessed March 30, 2015]. ClinicalTrials.gov . 23-1-2015. Ref Type: Electronic Citation.
- Hrkach J, Von HD, Mukkaram AM, Andrianova E, Auer J, Campbell T, et al. Preclinical development and clinical translation of a PSMA-targeted docetaxel nanoparticle with a differentiated pharmacological profile. Sci Transl Med. 2012;4:128ra39.View ArticlePubMedGoogle Scholar
- Natale R, Socinski M, Hart L, Lipatov O, Spigel D, Gershenhorn B, et al. 41 Clinical activity of BIND-014 (docetaxel nanoparticles for injectable suspension) as second-line therapy in patients (pts) with Stage III/IV non-small cell lung cancer. Eur J Cancer. 2014;50, Supplement 6:19.View ArticleGoogle Scholar
- Ahmad Z, Sharma S, Khuller GK. Inhalable alginate nanoparticles as antitubercular drug carriers against experimental tuberculosis. Int J Antimicrob Agents. 2005;26:298–303.View ArticlePubMedGoogle Scholar
- Pandey R, Sharma A, Zahoor A, Sharma S, Khuller GK, Prasad B. Poly (DL-lactide-co-glycolide) nanoparticle-based inhalable sustained drug delivery system for experimental tuberculosis. J Antimicrob Chemother. 2003;52:981–6.View ArticlePubMedGoogle Scholar
- Trivedi R, Redente EF, Thakur A, Riches DW, Kompella UB. Local delivery of biodegradable pirfenidone nanoparticles ameliorates bleomycin-induced pulmonary fibrosis in mice. Nanotechnology. 2012;23:505101.View ArticlePubMedGoogle Scholar
- Sadhukha T, Wiedmann TS, Panyam J. Inhalable magnetic nanoparticles for targeted hyperthermia in lung cancer therapy. Biomaterials. 2013;34:5163–71.View ArticlePubMedPubMed CentralGoogle Scholar
- Morton JG, Day ES, Halas NJ, West JL. Nanoshells for photothermal cancer therapy. Methods Mol Biol. 2010;624:101–17.View ArticlePubMedGoogle Scholar
- Efficacy Study of AuroLase Therapy in Subjects With Primary and/or Metastatic Lung Tumors. [Accessed March 30, 2015]. ClinicalTrials.gov. 23-9-2014. Ref Type: Electronic Citation.
- Lin EH, Chang HY, Yeh SD, Yang KY, Hu HS, Wu CW. Polyethyleneimine and DNA nanoparticles-based gene therapy for acute lung injury. Nanomedicine. 2013;9:1293–303.PubMedGoogle Scholar
- Konstan MW, Davis PB, Wagener JS, Hilliard KA, Stern RC, Milgram LJ, et al. Compacted DNA nanoparticles administered to the nasal mucosa of cystic fibrosis subjects are safe and demonstrate partial to complete cystic fibrosis transmembrane regulator reconstitution. Hum Gene Ther. 2004;15:1255–69.View ArticlePubMedGoogle Scholar
- Suk JS, Kim AJ, Trehan K, Schneider CS, Cebotaru L, Woodward OM, et al. Lung gene therapy with highly compacted DNA nanoparticles that overcome the mucus barrier. J Control Release. 2014;178:8–17.View ArticlePubMedPubMed CentralGoogle Scholar
- Wang H, Zheng L, Peng C, Shen M, Shi X, Zhang G. Folic acid-modified dendrimer-entrapped gold nanoparticles as nanoprobes for targeted CT imaging of human lung adencarcinoma. Biomaterials. 2013;34:470–80.View ArticlePubMedGoogle Scholar
- Bianchi A, Lux F, Tillement O, Cremillieux Y. Contrast enhanced lung MRI in mice using ultra-short echo time radial imaging and intratracheally administrated Gd-DOTA-based nanoparticles. Magn Reson Med. 2013;70:1419–26.View ArticlePubMedGoogle Scholar
- Stone V, Johnston H, Clift MJ. Air pollution, ultrafine and nanoparticle toxicology: cellular and molecular interactions. IEEE Trans Nanobiosci. 2007;6:331–40.View ArticleGoogle Scholar
- Chen Y, Preece JA, Palmer RE. Processing and characterization of gold nanoparticles for use in plasmon probe spectroscopy and microscopy of biosystems. Ann N Y Acad Sci. 2008;1130:201–6.View ArticlePubMedGoogle Scholar
- Nel AE, Madler L, Velegol D, Xia T, Hoek EM, Somasundaran P, et al. Understanding biophysicochemical interactions at the nano-bio interface. Nat Mater. 2009;8:543–57.View ArticlePubMedGoogle Scholar
- Dwivedi PD, Tripathi A, Ansari KM, Shanker R, Das M. Impact of nanoparticles on the immune system. J Biomed Nanotechnol. 2011;7:193–4.View ArticlePubMedGoogle Scholar
- Saputra D, Yoon JH, Park H, Heo Y, Yang H, Lee EJ, et al. Inhalation of carbon black nanoparticles aggravates pulmonary inflammation in mice. Toxicol Res. 2014;30:83–90.View ArticlePubMedPubMed CentralGoogle Scholar
- Ibricevic A, Guntsen SP, Zhang K, Shrestha R, Liu Y, Sun JY, et al. PEGylation of cationic, shell-crosslinked-knedel-like nanoparticles modulates inflammation and enhances cellular uptake in the lung. Nanomedicine. 2013;9:912–22.PubMedPubMed CentralGoogle Scholar
- Yang D, Zhao Y, Guo H, Li Y, Tewary P, Xing G, et al. [Gd@C(82)(OH)(22)](n) nanoparticles induce dendritic cell maturation and activate Th1 immune responses. ACS Nano. 2010;4:1178–86.View ArticlePubMedPubMed CentralGoogle Scholar
- Shurin MR, Yanamala N, Kisin ER, Tkach AV, Shurin GV, Murray AR, et al. Graphene oxide attenuates Th2-type immune responses, but augments airway remodeling and hyperresponsiveness in a murine model of asthma. ACS Nano. 2014;8:5585–99.View ArticlePubMedPubMed CentralGoogle Scholar
- Salem AK. A promising CpG adjuvant-loaded nanoparticle-based vaccine for treatment of dust mite allergies. Immunotherapy. 2014;6:1161–3.View ArticlePubMedGoogle Scholar
- Wang H, Joseph JA. Quantifying cellular oxidative stress by dichlorofluorescein assay using microplate reader. Free Radic Biol Med. 1999;27:612–6.View ArticlePubMedGoogle Scholar
- Li Q, Hu X, Bai Y, Alattar M, Ma D, Cao Y, et al. The oxidative damage and inflammatory response induced by lead sulfide nanoparticles in rat lung. Food Chem Toxicol. 2013;60:213–7.View ArticlePubMedGoogle Scholar
- Li B, Ze Y, Sun Q, Zhang T, Sang X, Cui Y, et al. Molecular mechanisms of nanosized titanium dioxide-induced pulmonary injury in mice. PLoS One. 2013;8, e55563.View ArticlePubMedPubMed CentralGoogle Scholar
- Lai X, Wei Y, Zhao H, Chen S, Bu X, Lu F, et al. The effect of Fe O and ZnO nanoparticles on cytotoxicity and glucose metabolism in lung epithelial cells. J Appl Toxicol. 2015;35(6):651–64.View ArticlePubMedGoogle Scholar
- Ema M, Tanaka J, Kobayashi N, Naya M, Endoh S, Maru J, et al. Genotoxicity evaluation of fullerene C60 nanoparticles in a comet assay using lung cells of intratracheally instilled rats. Regul Toxicol Pharmacol. 2012;62:419–24.View ArticlePubMedGoogle Scholar
- Naya M, Kobayashi N, Ema M, Kasamoto S, Fukumuro M, Takami S, et al. In vivo genotoxicity study of titanium dioxide nanoparticles using comet assay following intratracheal instillation in rats. Regul Toxicol Pharmacol. 2012;62:1–6.View ArticlePubMedGoogle Scholar
- Kyjovska ZO, Jacobsen NR, Saber AT, Bengtson S, Jackson P, Wallin H, et al. DNA damage following pulmonary exposure by instillation to low doses of carbon black (Printex 90) nanoparticles in mice. Environ Mol Mutagen. 2015;56(1):41–9.View ArticlePubMedGoogle Scholar
- Rubio L, Annangi B, Vila L, Hernandez A, Marcos R: Antioxidant and anti-genotoxic properties of cerium oxide nanoparticles in a pulmonary-like cell system. Arch Toxicol 2015. doi:10.1007/s00204-015-1468-y
- Danscher G. Autometallography. A new technique for light and electron microscopic visualization of metals in biological tissues (gold, silver, metal sulphides and metal selenides). Histochemistry. 1984;81:331–5.View ArticlePubMedGoogle Scholar
- Genter MB, Newman NC, Shertzer HG, Ali SF, Bolon B. Distribution and systemic effects of intranasally administered 25 nm silver nanoparticles in adult mice. Toxicol Pathol. 2012;40:1004–13.View ArticlePubMedGoogle Scholar
- Semmler-Behnke M, Kreyling WG, Lipka J, Fertsch S, Wenk A, Takenaka S, et al. Biodistribution of 1.4- and 18-nm gold particles in rats. Small. 2008;4:2108–11.View ArticlePubMedGoogle Scholar
- Choi HS, Ashitate Y, Lee JH, Kim SH, Matsui A, Insin N, et al. Rapid translocation of nanoparticles from the lung airspaces to the body. Nat Biotechnol. 2010;28:1300–3.View ArticlePubMedPubMed CentralGoogle Scholar
- Hussain S, Vanoirbeek JA, Haenen S, Haufroid V, Boland S, Marano F, et al. Prior lung inflammation impacts on body distribution of gold nanoparticles. Biomed Res Int. 2013;2013:923475.PubMedPubMed CentralGoogle Scholar
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