Research and Development of Nanoparticle Characterization Methods

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2 Research and Development of Nanoparticle Characterization Methods Project Outline This project aims at development of a risk evaluation method based on scientific knowledge for manufactured nanoparticles such as carbon nanotubes, fullerenes and titanium oxide. Background and Objectives Even with the same chemical composition, manufactured nanoparticles can show considerably different physicochemical characteristics depending on their structure. Because of this, conventional risk-analysis methods that have been commonly used for typical chemical substances may not be directly applied to manufactured nanoparticles. Also, as nanotechnology itself is in an advanced yet still developing technology field, characterization techniques have yet to be sufficiently established for manufactured particles. This research and development project, therefore, first focuses on the collection and compilation of relevant findings on the potential effects of manufactured nanoparticles of concern that may impact human health and/or the environment. The primary purpose of this project is to develop (1) characterization methods for manufactured nanoparticles to derive physicochemical characteristics required for risk assessment, (2) exposure assessment methods including analysis techniques to identify environmental concentrations, environmental emission sources, and fates and behaviors in the environment, and (3) basic hazardous property evaluation methods to eventually establish risk assessment methods applicable to manufactured nanoparticles using these methods. Activities Exposure assessment methods that include characterization techniques, environmental concentrations, environmental emission sources, and analysis of fates and behaviors in the environment, which are the basis of hazard evaluation, exposure analysis and risk assessment for manufactured nanoparticles such as carbon nanotubes, fullerenes, titanium oxides, etc. will be developed. These basic hazard evaluation methods will be useful for practical use and meet international standards. Risk assessment for nanoparticles will also be carried out using the new methods to eventually provide recommendations for administrative bodies and companies to properly manage manufactured nanoparticles. 1 Development of characterization methods for manufactured nanoparticles 2 Development of exposure evaluation methods for nanoparticles 3 Development of hazard evaluation methods for manufactured nanoparticles 4 Development of a framework for risk evaluation management Project Outline Period: FY2006-FY2010, FY2007 Budget: 430 million yen Project Organization

3 Unique Feature of This Project (Key Strategy) Pioneer work on evaluation for manufactured nanoparticles, including an entire process from preparation and characterization through animal tests. Hazard evaluation using the biaxial approach instead of conventional stepwise evaluation Horizontal line : An entire hazard evaluation test from in vitro through in vivo stages will be carried out for several manufactured nanoparticles of concern with respect to human health and their influence on humans will be extrapolated. Vertical line : At the same time, the potential hazard of manufactured nanoparticles from a wide variety of materials will be evaluated through in vitro tests. The relative hazard potential will be estimated, and the results will be analyzed and then compared to the properties of manufactured nanoparticles. 2

4 Characterization Methods for Manufactured Nanoparticles Targets Preparation technologies for manufactured nanoparticles Development of technologies regarding aerosol generation and dispersion into liquid Preparation and publication of sample preparation manuals to collect data for exposure analysis and manuals for hazard evaluation tests Characterization technologies for manufactured nanoparticles Development of measurement and calibration technologies for particle size distribution and concentration of manufactured nanoparticles from 1nm to 100nm using practical methods Development of technology to statistically analyze the shape and size of manufactured nanoparticles such as carbon nanotubes, fullerenes and titinium oxides in tissue samples from electron microscope images Development of a method to measure the filter capture efficiency of manufactured nanoparticles in air Development of calibration technologies to eliminate errors due to the shape and material of manufactured nanoparticles Preparation and publication of a manual for all of the technologies mentioned above Research themes (1) Development of preparation technologies for manufactured nanoparticles Technologies for aerosol generation and dispersion into liquid necessary for exposure analysis and hazard evaluation tests for manufactured nanoparticles will be developed. Test sample preparation manuals will be drawn up, and methods to evaluate the capture efficiency of aerosol nanoparticles will be developed and compiled in a manual. (2) Development of characterization methods for manufactured nanoparticles in media Precise and reliable methods, including equipment calibration technologies, for measuring particle concentration by weight and number in such media as air, liquid, living organisms and dosage carrier, as well as surface area, particle size, particle size distribution, shape, particle component and degree of aggregation will be developed for hazard evaluation tests and exposure evaluation of manufactured nanoparticles. Characterization methods for manufactured nanoparticles for exposure analysis and hazard evaluation tests will also be compiled in a manual. In addition, physicochemical properties of manufactured nanoparticles necessary for evaluation will be measured. Development of characterization technologies and sample preparation technologies for nanoparticles 3

5 Exposure Evaluation Methods for Nanoparticles Targets Emission scenario Environmental behavior model Exposure evaluation Research themes Preparation of emission scenario documents, including information on the emission amount for thirty categories of manufactured nanoparticles classified by type and application Development of an environmental behavior model to analyze the dynamic behavior of manufactured nanoparticles in a workplace environment and local emission sources Evaluation of exposure in a workplace environment and local emission sources and publication of the results (1) Development of emission scenarios Emission scenarios for manufactured nanoparticles classified by type and application will be constructed by collecting information and interviewing suppliers and customers regarding emission sources. The quantitative emission factors of major emission sources will be estimated by actual measurement and computer simulation. Future emission amounts will also be predicted by referring to technology and market forecasts. (2) Environmental behavior modeling Parameters necessary for analyzing the behavior of manufactured nanoparticles emitted into air will be extracted for the case of a workplace environment and local emission source sites. Methods to obtain the needed parameters using laboratory experiments and computer simulation will also be developed with an environmental behavior model which can explain the behavior of manufactured nanoparticles in the environment using the extracted parameters. The model will be verified by comparing simulated test results and field monitoring data in the environment. (3) Development of exposure evaluation technologies Typical manufactured nanoparticles in a workplace environment and local emission sources will be selected by considering differences in particle features, environmental behavior and evaluation results. Exposure levels will be evaluated on the basis of estimated emission amounts and concentrations, which will be obtained from analysis of emission scenarios, environmental behavior modeling and concentrations actually measured during field monitoring. Exposure assessment for nanoparticles Exposure assessment during the lifecycle of nanoparticles 4

6 Hazard Evaluation Methods for Manufactured Nanoparticles Targets Hazard evaluation test Application of conventional hazard evaluation test methods to manufactured nanoparticles to understand their characteristics and publication of test results, test methods and characterization methods Identification of latent responses to manufactured nanoparticles which could affect human health and the environment and clarification of the mechanism and relationship between dosage and reaction Clarification of procedures for sample pre-treatment, dosage, observation after dosage, compiling results and requirements for characterization in each process, based on the features of manufactured nanoparticles Development of a movement model for manufactured nanoparticles in vivo, methods which could complement or modify conventional evaluation tests, and new evaluation methods if necessary, and publication in a document Inhalation test apparatus Development of an inhalation test apparatus for manufactured nanoparticles Latent human influence of manufactured nanoparticles Development of a proposal for a concept to extrapolate hazard evaluation results of animal tests to human health as potential influences Research themes (1) Development of a hazard evaluation test for manufactured nanoparticles The problems of conventional test methods for inhalation exposure, tracheal instillation and dermal exposure will be investigated, and literature regarding hazard tests for manufactured nanoparticles will be collected and analyzed. The conventional hazard evaluation method will be adapted for application to manufactured nanoparticles to understand their characteristics and specific responses to nanoparticles will be confirmed and verified. The mechanisms and relationships between dosage and response will be analyzed as well. Technology which can simulate the movement of manufactured nanoparticles in vivo, methods which can complement or modify conventional hazard evaluation tests, and any necessary new hazard evaluation methods will also be developed. (2) Development of an inhalation exposure apparatus (or experiment equipment) A system to transport air containing manufactured nanoparticles with uniform distribution and concentration to an exposure chamber for in vivo tests will be designed. Technologies for continuous measurement of particle size distribution and concentration in air during inhalation tests will also be developed. An inhalation exposure test apparatus will then be constructed and applied to manufactured nanoparticles. (3) Research to extrapolate the results of hazard evaluation to the human body Hazard evaluation results obtained in this project and additional information from literature will be used to clarify potential problems when hazard information derived from animal tests is extrapolated to the human body, and the basic concept for handling such problems will be proposed. A Framework for Risk Evaluation Management Targets Detailed risk evaluation Development of a framework for risk evaluation of manufactured nanoparticles which this project should treat and extraction of problems, evaluation of risk regarding the possibility of latent influence of manufactured nanoparticles on the human body and environment, summarizing of the ways to properly manage such risk, and disclosing them Social acceptance Formulation and publication of a vision for social acceptance of nanotechnologies using manufactured nanoparticles Research themes (1) Detailed risk evaluation for manufactured nanoparticles Several suitable manufactured nanoparticles from metal, metal oxide and carbon derivatives will be selected by taking into account their production and/or consumption amount as well as future value, and information concerning the influence of manufactured nanoparticles on human health and the environment will be collected from literature and analyzed. Detailed risk assessment of the selected manufactured nanoparticles will be carried out after characterization, exposure evaluation and hazard evaluation. During the risk assessment process, facts based on scientific evidence, hypotheses and extrapolation due to lack of knowledge, judgment, data fluctuation, uncertainty and other factors will be specified and dealt with separately. The state of concern regarding manufactured nanoparticles will be reflected as well. Peer review performed by outside experts will also be utilized in order to achieve a fair assessment. In addition to risk assessment, a concept for appropriate manufactured nanoparticle risk management will be developed using the research results outlined below for the social acceptance of nanotechnologies. (2) Research on social acceptance of nanotechnologies Social acceptance of nanotechnologies that use manufactured nanoparticles will be studied in terms of cultural diversity, social and economic benefit, detriment and benefit, social system, morals, natural science, and social science. A vision will be formulated for the purpose of advancing industry use and realizing a safe and secure life while also maximizing the social benefits offered by using nanotechnologies. 5

7 Developed inhalation test system The above show the inhalation test system. The nanosize particles are generated using a pressurized particle generator and then transported to the inhalation chamber via diffusion dryers. The size distribution and number are monitored at points prior to and inside the inhalation chamber. During a preliminary test, it was ascertained that particle size and number remained stable and unchanged for a month. 6

8 New Energy and Industrial Technology Development Organization Biotechnology and Medical Technology Development Department 19F MUZA Kawasaki Central Tower, 1310, Omiya-cho, Saiwai-ku Kawasaki City, Kanagawa JAPAN Tel: Fax: