博士論文概要

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Graduate School of Advanced Science and Engineering, Waseda University

博士論文概要

Doctor Thesis Synopsis

論文題目

The Effects of TiO 2 Nanoparticles on Cellular Responses

申請者 (Applicant Name)

Qingqing SUN

スンチンチン

Department of Nanoscience and Nanoengineering, Research on Nanobiomaterials

December, 2017

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1 Abstract

Nanotechnology is an interdisciplinary branch of science that integrates biology, physics, chemistry, and engineering.

Nanotechnology enables the production of materials and devices with novel structures and unique physical and chemical properties. Furthermore, advances in medical science nanotechnology have led to the development of titanium dioxide (TiO2), silver, silica, and gold nanomaterials suitable for biomedical applications. TiO2 nanoparticles (NPs) were the earliest industrial products and are one of the most highly manufactured nanomaterials in the world, according to the U.S. National Nanotechnology Initiative. TiO2 nanoparticles have generated considerable interest for use in a variety of applications, such as drug delivery, diagnostics, imaging, sunscreens, catalysts, paints, and food additives. The widespread use of TiO2 nanoparticles in daily life has led to the belief that they are generally safe and non-toxic.

However, nanoparticles can be incorporated in the human body through three main pathways: gastrointestinal, dermal, and pulmonary absorption. Once inside the body, nanoparticles can stimulate the production of reactive oxygen species (ROS), damage DNA, and ultimately induce apoptosis, cytotoxicity and affect cell mobility. Therefore, designing suitable nanoparticles exhibiting a high degree of biocompatibility is critically important.

Furthermore, how to evaluate if nanoparticles were safe or not played vital role in the safe nanoparticle design. Some studies simply evaluate NPs from the low and high cell viability after treatment with cells, which cause big problems to the future NPs design for safe usage. High cell viability of NPs is not equal to be safe and low cell viability of NPs is possible to be improved. To solve these problems, NPs should be studies from the different parameters which affected different cellular receptors, cellular uptake pathways, and stimulated different signaling transduction and cellular response. Through these detailed information, we could track the NPs after exposure to cells and detected their safety all-roundly, and finally improve the NPs properties for safe usage in our daily life. Therefore, our work chose two NPs parameters, sizes and doses, and focused on their effects on cellular responses in the aim of improve the safe usage of NPs. Based on these, our work was divided into five chapters.

First chapter:

In this part, we describe the introduction of TiO2 NPs and their applications in our daily life, and then the internalization pathways of TiO2 NPs to human and the safety problems induced by them. Besides that, we introduce the NPs parameters and cellular responses after NPs exposure, and the reported study progress about the NPs parameters and cellular responses. Finally, we put forward the problems to be solved in our work and how to solve them.

Second chapter:

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In this chapter, the problems to be solved is about the doses of NPs and cellular response. We describe the importance of doses to cells and problems to be solved about doses of NPs. Then through the different cellular responses between the low and high doses, we analyze and study the mechanisms of different cellular responses, and finally concluded the importance of doses of NPs and provide useful information on the safe usage of NPs in our daily life.

Third chapter:

This part of work describes the sizes effects of TiO2 NPs on cellular responses. First, we put forward the problems to be solved about the sizes of NPs, and the strategies to solve the problems. Next, we prepared the uniform NPs with different sizes and characterized NPs to confirm the successful preparation of uniform NPs. Third, the uniform NPs were used to study the relationship between sizes and apoptosis, including the cell viability assay, the apoptosis and caspase 3 activities assays to confirm the size-dependent apoptosis induced by NPs. Forth, we found the mechanisms of size- dependent apoptosis. Finally, our work showed size-dependent apoptosis and provides information to decrease side effects of NPs for safe usage through optimizing NPs sizes.

Forth chapter:

This work focused on the effects of NPs sizes on cell migration. We introduce the cell migration and their function and importance to mammal cells. Then, the mechanisms of cell migration are introduced, including the receptors and molecular that control and affect cell migration, and the changes of focal adhesions during the movement of cells, and the effects of cell skeleton on cell migration. Following that, the reported studies about the effects of NPs on cell migration are introduced and then we put forward the aim of the study in this work and the hypothesis that the endocytosis of NPs affected integrin beta 1 trafficking and then decreased the expression of integrin beta 1, and thus inhibited cell migration. Then the cell migration, the endocytosis trafficking of NPs and integrin beta 1 and pFAK, and the quantification and observation of integrin beta 1, pFAK, and F-actin were checked to find the relationship and mechanisms of size-dependent inhibition of cell migration. Finally, our work showed size-dependent inhibition of cell migration, which provide important reference for future safe NPs design by controlling sizes of NPs.

Fifth chapter:

The conclusion of our work is introduced. Our work studied the effects of doses and sizes of NPs and found the relative responses and explained the relationships between doses and sizes and their relative responses from the molecular mechanisms. The first part showed that high dosed decreased cell viability, but low doses of NPs promoted cell proliferation through inducing the aggregation of hepatocyte growth factor receptor (HGFR), which recruit more

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signaling molecules to strength the signaling transduction pathways and promote cell proliferation. The second part showed size-dependent apoptosis caused by NPs. Size of NPs affects cellular uptake pathways and then cellular uptake ratios, which stimulated size-dependent activities of caspase 3 and finally induced size-dependent apoptosis. The third part displayed size-dependent inhibition of cell migration by affecting the endocytosis of integrin beta 1. Larger NPs promoted more internalization of integrin beta 1 and pFAK with NPs. And then the endocytic NPs, integrin beta 1 and pFAK was transferred to lysosome for degradation, which decreased expression of integrin beta 1 and pFAK and thereafter affect F-actin expression and structure, and finally inhibited cell migration. Therefore, our work provides useful information for future safe NPs design with decreased side effects through controlling NPs sizes and doses.

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No.

1

早稲田大学博士（工学）学位申請研究業績書

(List of research achievements for application of doctorate (Dr. of Engineering), Waseda University)

氏名(Qingqing SUN)

印( )

（

As of April, 2018

）種類別

(By Type)

題名、発表・発行掲載誌名、発表・発行年月、連名者（申請者含む）

(theme, journal name, date & year of publication, name of authors inc. yourself)

Paper

○ Uniform TiO2 nanoparticles induce apoptosis in epithelial cell lines in a size-dependent manner

Biomaterials Science 5 (5), 2017, 1014-1021 DOI: 10.1039/c6bm00946h.

Q Sun, T Ishii, K Kanehira, T Sato, A Taniguchi

○Low doses of TiO2-polyethylene glycol nanoparticles stimulate proliferation of hepatocyte cells

Science and Technology of advanced materials, 17 (1), 2016, 669-676 DOI: 10.1080/14686996.2016.1239499

Q Sun, K Kanehira, A Taniguchi

Studies of Silk Fibroin/Poly (Lactic-Co-Glycolic Acid) Scaffold, Prepared by Thermally Induced Phase Separation, as a Possible Wound Dressing. Science of Advanced Materials 8 (5), 2016, 1045-1052

Y Liu*, Q Sun, S Wang, J Fan, A Chen, W Wu. (Equally first co-author)

Preparation of SF/PLGA Scaffold with Microporous-Nano/Microfibrous Architecture by Thermal Induced Phase Separation. Science of Advanced Materials 7 (11), 2015, 2380-2387 Y Liu*, Q Sun, S Wang, J Fan, A Chen, W Wu. (Equally first co-author)

Preparation of methotrexate-loaded, large, highly-porous PLLA microspheres by a high- voltage electrostatic antisolvent process. Journal of Materials Science: Materials in Medicine 24 (8), 2013, 1917-1925

AZ Chen, YM Yang, SB Wang, GY Wang, YG Liu, Q Sun

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No.

2

早稲田大学博士（工学）学位申請研究業績書

(List of research achievements for application of doctorate (Dr. of Engineering), Waseda University)

種類別By Type

題名、発表・発行掲載誌名、発表・発行年月、連名者（申請者含む）

(theme, journal name, date & year of publication, name of authors inc. yourself)

Presentation Oral Presentations

1. 2017.11第12回ナノバイオメディカル学会（奨励赏，筑波，日本）

Qingqing Sun, A. Taniguchi

2. 2017.08 IUMRS-ICAM（京都，日本）

3. 2017.01第26回インテリジェント材料・システムシンポジウムプログラ（東京，日

本）

Poster presentations

1. 2017.01 つくば医工連携フォーラム（研究奨励赏，筑波，日本）

2. 2016.11日本バテリアル学会シンポジウム（福岡，日本）

3. 2016.10 NIMS week（東京，日本）

4. 2016.06 NanoCentre Annual Conference 2016（ International conference , Adelaide, Australia）

5. 2016.03 MANA International Symposium（筑波，日本）

6. 2015.11 日本バイオマテリアル学会シンポジウム2015（京都，日本）

7. 2015.07 The 6th Waseda-NIMS International Symposium（東京，日本）

8. 2015.03 MANA International Symposium（筑波，日本）

博 士 論 文 概 要

Graduate School of Advanced Science and Engineering, Waseda University