Lai W, Hu Z, Fang Q (2013) The Concerns on Biosafety of Nanomaterials. JSM Nanotechnol Nanomed 1(2): 1009.

Nanomaterials, with sizes range from 0.1 to 100 nm, are similar to many biomacromolecules and organelles. When the size of a material decreases to nanometer level, small size effect, surface effect, quantum size effect and quantum tunneling effect will play significant roles, and enable nanomaterials with new properties, such as the increasing hardness and strength, super paramagnetism, strong surface adsorption capacity, chemical reactivity and quantum properties.

Today, various kinds of nanomaterials have been used in commercial and industrial products. ZnO and TiO2 nanoparticles are widely used on cellulosic fabrics for UV-protection purpose [1,2]. A lot of cosmetics and skin products contain ZnO and TiO2 nanoparticles as sun-screening active ingredients [3,4], together with nano silver, gold and other inorganic nano-structured materials to gain antimicrobial activity [5-7]. Nanoscale CeO2 can serve as fuel additives and reduce fuel consumption, CO2 emissions, and particulate emissions [8,9]. Al?O? nanoparticles are widely used in plastic, rubber and ceramic to reinforcing and toughening the products. Nanotechnology and nanomaterials are also very promising in improving the diagnosis, treatment and monitoring of many diseases. Studies have shown that incorporation of nanotechnology in medicine increases solubility, stability, targeting, biocompatibility, permeability and controllability of drugs and vaccines [10-12].

Despite the increasing interest and effort in the development and application of nanomaterials, there are increasing concerns about their potential toxicity. In fact, the number of nanomedicine being approved for clinical is limited [13,14]. A lot of uncertainties remain as how nanoparticles interact with biomacromolecules after entering into the human body; how they accumulate, degrade and finally leave the body; how different organs, tissues and the circulation system are affected. There are reports that nanomaterials can cause damage to cells by generating reactive oxygen species which will result in DNA damage, lipid peroxidation and protein denaturation [15-17]. In addition, proteins and nucleic acids may stick to nanoparticals upon their entrance into the cells [18-22], interfering metabolic pathways and ultimately cell death.

A number of in vivo and in vitro studies have been performed to assess the potential toxicity of nanomaterials. At cellular level, methods that are generally used include cell morphology analysis, tissue staining, cell viability assay, ROS analysis, NO assay, LDH or MTT assay, cell cycle analysis and cytokine (IF8, IL-6 or TNFalpha etc.) release test. These assays are carried out to explore how the size, shape, and surface properties of nanoparticles affect cell viability and their in vivo distribution, cellular uptake, subcellular location, metabolism and degradation [10,20,23-26]. In vivo studies showed that nanomaterials can accumulate in many organs, for instance, liver, spleen, lung or kidney, depending on their characteristics and how they are administrated [27]. Oxidative stress are detected in cells exposed to nanomaterials such as Ag [28], Au [29], copper and copper oxide [30], TiO2 [31], ZnO [32], CeO2 [33], Al?O? [34], carbon nanotube [35,36] and et al. Recently, genomic and proteomic technologies have also been applied to study the biological effects and toxicity of nanomaterials [37]. These high throughput analysis provide a more comprehensive view of how molecules in the biological network response to the presence of nanoparticles. Genomic instability [38-40], inflammatory response [41,42], apoptosis [43], protein phosphorylation [44,45] are found to be affected by exposure to nanomaterials.

Despite the efforts on the studies of nanomaterial safety, there remain a lot of problems. Firstly, these studies are not systematic, most studies use only one cell line or one tissue of the animal models. The methods reported are different and therefore no comparisons can be made among different materials and studies. Secondly, most studies report observations on cellular or tissue level, there are still not enough studies on how nanomaterials interact with biomolecules and finally the mechanism leads to toxicity or biological effects. The third concern is that among these studies there are contradictory results in the evaluation of toxicity of the same kind nanomaterials. One example is that nano Au was observed to show both causing oxidative stress [46] and antioxidative stress [47,48]. And this happens to CeO2 [49] and carbon nanotube [50] too. Factors including different concentration, administration procedures, fabrication and processing of nanoparticles and other details can all lead to inconsistent results

As a new area and many nanomaterials are newly engineered, standardized preparation and characterization methods of many nanomaterials are not available. With the development of nanomaterials and nanotechonolgy, there is a great need to set up regulations and standards based on comprehensive studies on biosafety and bioeffects of nanomaterials. It is critical to develop a systematic and standardized method that is accurate and repeatable for the analysis of the biological effects and safety of nanomaterials at tissue, cell and molecular levels. The method should start with a comprehensive and detail characterization of each nanomaterial before in vitro/vivo analysis, which includes dimensions, compositions, purity, surface charges et al. The method should be applicable to the analysis of most nanomaterials. In addition, a series of dosage and exposure time to nanomaterials should be designed to monitor the effects. This will allow comparisons of toxicity of different nanomaterials to same cells and tissues, and therefore facilitate the standardized regulations for nanomaterial safety

With the increasing interest in nanomaterials and concern of their biological effects and safety, more efforts are being invested in these fields of studies. It is promising that in the near future a systematic and accurate method to evaluate the safety of nanoparticles will be developed and consents on by fields of nanomaterials. This will in turn improve the regulations and standards of nanomaterials preparation, processing, characterization and application.

This work is supported by Chinese Academy of Science 100 plan awarded to QF and ZH.

1. Farouk A, Sharaf S, Abd El-Hady MM. Preparation of multifunctional cationized cotton fabric based on TiO2 nanomaterials. Int J Biol Macromol. 2013; 61C: 230-237.

2. El-Hady MM, Farouk A, Sharaf S. Flame retardancy and UV protection of cotton based fabrics using nano ZnO and polycarboxylic acids. Carbohydr Polym. 2013; 92: 400-406.

3. Schmid K, Riediker M. Use of nanoparticles in Swiss Industry: a targeted survey. Environ Sci Technol. 2008; 42: 2253-2260.

4. Nohynek GJ, Dufour EK, Roberts MS. Nanotechnology, cosmetics and the skin: is there a health risk? Skin Pharmacol Physiol. 2008; 21: 136- 149.

5. Selvam S, Rajiv Gandhi R, Suresh J, Gowri S, Ravikumar S, Sundrarajan M. Antibacterial effect of novel synthesized sulfated β-cyclodextrin crosslinked cotton fabric and its improved antibacterial activities with ZnO, TiO2 and Ag nanoparticles coating. Int J Pharm. 2012; 434: 366- 74.

6. Hebeish AA, Abdelhady MM, Youssef AM. TiO2 nanowire and TiO2 nanowire doped Ag-PVP nanocomposite for antimicrobial and selfcleaning cotton textile. Carbohydr Polym. 2013; 91: 549-559.

7. Dastjerdi R, Montazer M. A review on the application of inorganic nano-structured materials in the modification of textiles: focus on anti-microbial properties. Colloids Surf B Biointerfaces. 2010; 79: 5-18.

8. Park B, Donaldson K, Duffin R, Tran L, Kelly F, Mudway I, et al. Hazard and risk assessment of a nanoparticulate cerium oxide-based diesel fuel additive - a case study. Inhal Toxicol. 2008; 20: 547-566.

9. Cassee FR, van Balen EC, Singh C, Green D, Muijser H, Weinstein J, et al. Exposure, health and ecological effects review of engineered nanoscale cerium and cerium oxide associated with its use as a fuel additive. Crit Rev Toxicol. 2011; 41: 213-229.

10. Fröhlich E. The role of surface charge in cellular uptake and cytotoxicity of medical nanoparticles. Int J Nanomedicine. 2012; 7: 5577-5591.

11. You C, Han C, Wang X, Zheng Y, Li Q, Hu X, et al. The progress of silver nanoparticles in the antibacterial mechanism, clinical application and cytotoxicity. Mol Biol Rep. 2012; 39: 9193-9201.

12. Doll TA, Raman S, Dey R, Burkhard P. Nanoscale assemblies and their biomedical applications. J R Soc Interface. 2013; 10: 20120740.

13. Eifler AC, Thaxton CS. Nanoparticle therapeutics: FDA approval, clinical trials, regulatory pathways, and case study. Methods Mol Biol. 2011; 726: 325-338.

14. Ventola CL. The nanomedicine revolution: part 3: regulatory and safety challenges. P T. 2012; 37: 631-639.

15. Zhang WX, Karn B. Nanoscale environmental science and technology: challenges and opportunities. Environ Sci Technol. 2005; 39: 94A-95A.

16. Lanone S, Boczkowski J. Biomedical applications and potential health risks of nanomaterials: molecular mechanisms. Curr Mol Med. 2006; 6: 651-663.

17. Hoshino A, Hanada S, Yamamoto K. Toxicity of nanocrystal quantum dots: the relevance of surface modifications. Arch Toxicol. 2011; 85: 707-720.

18. Arvizo RR, Giri K, Moyano D, Miranda OR, Madden B, McCormick DJ, et al. Identifying new therapeutic targets via modulation of protein corona formation by engineered nanoparticles. PLoS One. 2012; 7: e33650.

19. Lai ZW, Yan Y, Caruso F, Nice EC. Emerging techniques in proteomics for probing nano-bio interactions. ACS Nano. 2012; 6: 10438-10448.

20. Tenzer S, Docter D, Rosfa S, Wlodarski A, Kuharev J, Rekik A, et al. Nanoparticle size is a critical physicochemical determinant of the human blood plasma corona: a comprehensive quantitative proteomic analysis. ACS Nano. 2011; 5: 7155-7167.

21. Zhang H, Burnum KE, Luna ML, Petritis BO, Kim JS, Qian WJ, et al. Quantitative proteomics analysis of adsorbed plasma proteins classifies nanoparticles with different surface properties and size. Proteomics. 2011; 11: 4569-4577.

22. Walczyk D, Bombelli FB, Monopoli MP, Lynch I, Dawson KA. What the cell “sees” in bionanoscience. J Am Chem Soc. 2010; 132: 5761-5768.

23. Kumar V, Kumari A, Guleria P, Yadav SK. Evaluating the toxicity of selected types of nanochemicals. Rev Environ Contam Toxicol. 2012; 215: 39-121.

24. Albanese A, Tang PS, Chan WC. The effect of nanoparticle size, shape, and surface chemistry on biological systems. Annu Rev Biomed Eng. 2012; 14: 1-16.

25. Kim ST, Saha K, Kim C, Rotello VM. The role of surface functionality in determining nanoparticle cytotoxicity. Acc Chem Res. 2013; 46: 681- 691.

26. Karakoti AS, Hench LL, Seal S. The potential toxicity of nanomaterials— The role of surfaces. JOM. 2006; 58: 77-82.

27. Almeida JP, Chen AL, Foster A, Drezek R. In vivo biodistribution of nanoparticles. Nanomedicine (Lond). 2011; 6: 815-835.

28. Prasad RY, McGee JK, Killius MG, Suarez DA, Blackman CF, Demarini DM, et al. Investigating oxidative stress and inflammatory responses elicited by silver nanoparticles using high-throughput reporter genes in HepG2 cells: Effect of size, surface coating, and intracellular uptake. Toxicol In Vitro. 2013; 27: 2013-21.

29. Li JJ, Hartono D, Ong CN, Bay BH, Yung LY. Autophagy and oxidative stress associated with gold nanoparticles. Biomaterials. 2010; 31: 5996-6003.

30. Triboulet S, Aude-Garcia C, Carriere M, Diemer H, Proamer F, Habert A, et al. Molecular responses of mouse macrophages to copper and copper oxide nanoparticles inferred from proteomic analyses. Mol Cell Proteomics. 2013; .

31. Wang J, Ma J, Dong L, Hou Y, Jia X, Niu X, et al. Effect of anatase TiO2 nanoparticles on the growth of RSC-364 rat synovial cell. J Nanosci Nanotechnol. 2013; 13: 3874-3879.

32. Alarifi S, Ali D, Alkahtani S, Verma A, Ahamed M, Ahmed M, et al. Induction of oxidative stress, DNA damage, and apoptosis in a malignant human skin melanoma cell line after exposure to zinc oxide nanoparticles. Int J Nanomedicine. 2013; 8: 983-993.

33. Cheng G, Guo W, Han L, Chen E, Kong L, Wang L, et al. Cerium oxide nanoparticles induce cytotoxicity in human hepatoma SMMC7721 cells via oxidative stress and the activation of MAPK signaling pathways. Toxicol In Vitro. 2013; 27: 1082-1088.

34. Alshatwi AA, Subbarayan PV, Ramesh E, Al-Hazzani AA, Alsaif MA, Alwarthan AA. Aluminium oxide nanoparticles induce mitochondrialmediated oxidative stress and alter the expression of antioxidant enzymes in human mesenchymal stem cells. Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2013; 30: 1-10.

35. Shvedova AA, Pietroiusti A, Fadeel B, Kagan VE. Mechanisms of carbon nanotube-induced toxicity: focus on oxidative stress. Toxicol Appl Pharmacol. 2012; 261: 121-133.

36. Haniu H, Matsuda Y, Usui Y, Aoki K, Shimizu M, Ogihara N, et al. Toxicoproteomic evaluation of carbon nanomaterials in vitro. J Proteomics. 2011; 74: 2703-2712.

37. Larguinho M, Baptista PV. Gold and silver nanoparticles for clinical diagnostics - From genomics to proteomics. J Proteomics. 2012; 75: 2811-2823.

38. Li JJ, Lo SL, Ng CT, Gurung RL, Hartono D, Hande MP, et al. Genomic instability of gold nanoparticle treated human lung fibroblast cells. Biomaterials. 2011; 32: 5515-5523.

39. de Lima R, Seabra AB, Durán N. Silver nanoparticles: a brief review of cytotoxicity and genotoxicity of chemically and biogenically synthesized nanoparticles. J Appl Toxicol. 2012; 32: 867-879.

40. Oesch F, Landsiedel R. Genotoxicity investigations on nanomaterials. Arch Toxicol. 2012; 86: 985-994.

41. Ganguly K, Upadhyay S, Irmler M, Takenaka S, Pukelsheim K, Beckers J, et al. Impaired resolution of inflammatory response in the lungs of JF1/Msf mice following carbon nanoparticle instillation. Respir Res. 2011; 12: 94.

42. Teeguarden JG, Webb-Robertson BJ, Waters KM, Murray AR, Kisin ER, Varnum SM, et al. Comparative proteomics and pulmonary toxicity of instilled single-walled carbon nanotubes, crocidolite asbestos, and ultrafine carbon black in mice. Toxicol Sci. 2011; 120: 123-135.

43. Horie M, Kato H, Fujita K, Endoh S, Iwahashi H. In vitro evaluation of cellular response induced by manufactured nanoparticles. Chem Res Toxicol. 2012; 25: 605-619.

44. Ge Y, Bruno M, Wallace K, Winnik W, Prasad RY. Proteome profiling reveals potential toxicity and detoxification pathways following exposure of BEAS-2B cells to engineered nanoparticle titanium dioxide. Proteomics. 2011; 11: 2406-2422.

45. Prasad RY, Chastain PD, Nikolaishvili-Feinberg N, Smeester L, Kaufmann WK, Fry RC. Titanium dioxide nanoparticles activate the ATM-Chk2 DNA damage response in human dermal fibroblasts. Nanotoxicology. 2013; 7: 1111-1119.

46. Pan Y, Bartneck M, Jahnen-Dechent W. Cytotoxicity of gold nanoparticles. Methods Enzymol. 2012; 509: 225-242.

47. Menchón C, Martín R, Apostolova N, Victor VM, Alvaro M, Herance JR, et al. Gold nanoparticles supported on nanoparticulate ceria as a powerful agent against intracellular oxidative stress. Small. 2012; 8: 1895-1903.

48. Barathmanikanth S, Kalishwaralal K, Sriram M, Pandian SR, Youn HS, Eom S, et al. Anti-oxidant effect of gold nanoparticles restrains hyperglycemic conditions in diabetic mice. J Nanobiotechnology. 2010; 8: 16.

49. Hosseini A, Baeeri M, Rahimifard M, Navaei-Nigjeh M, Mohammadirad A, Pourkhalili N, et al. Antiapoptotic effects of cerium oxide and yttrium oxide nanoparticles in isolated rat pancreatic islets. Hum Exp Toxicol. 2013; 32: 544-553.

50. Herzog E, Byrne HJ, Casey A, Davoren M, Lenz AG, Maier KL, et al. SWCNT suppress inflammatory mediator responses in human lung epithelium in vitro. Toxicol Appl Pharmacol. 2009; 234: 378-390.