第81回フロンティア材料研究所講演会（Minoru Taya教授）
| 開催日時 | 2018年12月17日 16:00~17:00 |
|---|---|
| 開催場所 | R2棟6F 大会議室 |
| 主催 | フロンティア材料研究所 |
| 連絡先 | 細田 秀樹 教授 (E-Mail: hosoda.h.aa@m.titech.ac.jp 内線: 5057) |
プログラム等
講演者 ： Minoru Taya教授
（CIMS Nabtesco Endowed Chair Professor, University of Washington）
講演題目： 「Design of nanorobotics based on FePd nanohelices for cancer treatment」
Nanohelices are key building blocks for biological materials with some examples being the protein and the double helix of DNA. Nanohelix actuators are also seen in some biological species; for example, rapid stalk coiling (thus rapid shrinkage) of Vorticella convallaria seems to be driven not by just external Ca2+ ions but also intracellular Ca2+ storage site1-4. Recently three chemists are honored as Nobel Laureates in Chemistry, in 2016 for their pioneering work on design of synthetic molecular motor machines which exhibit both translational and rotational motions under redox reactions and also light-driven stimulus5-7. Despite the promising future in using bioinspired design of molecular machine and nanohelix engineering, the processing of such synthetic molecular elements and nanohelices in high yield is still in its infancy. Exact control of molecular motors under redox reactions is NOT available.
Taya group studied the actuation mechanisms associated with bulk FSMA Fe70Pd30(hereafter FePd) to find that the key mechanism of actuation of FePd actuators is stress-induced martensite (SIM) phase transformation under applied magnetic field (either constant or gradient field)1. Scientific challenge is lack of the phase transformation diagram of nano-sized FSMA active materials where the martensite start temperature (Ms) is expected to be shifted toward lower temperature, which is NOT desired for end-users of the FePd NRs, particularly in biomedical applications. Fortunately, as-processed FePd nanomaterials (both nanowires(NWs)and nanohelices(NHs)) possess residual stress, which would promote SIM phase transformation, even at desired room temperature use condition. Recently, we have explored new NR based on flexible FSMA FePd NHs, which have been successfully processed. Our FePd NR is composed of a single FePd NH (tail) and FePd NW (head) attached in series. The FePd NR can swim under an applied rotational magnetic field, and it can vibrate under an oscillating magnetic field which is verified by our recent molecular dynamics model8. Use of FePd based NRs under applied magnetic field is much more controllable as compared with the above organic molecular machines. We are currently using FePd NH based untethered NRs as treatment of difficult-to-cure cancer cells where targeted cells are expected to undergo cell damage (apoptosis/necrosis) by mechanical stress-induced cell death (MSICD).
For this talk, I will discuss on several models to support the above phase transformation behavior and nano-motions of FePd nanomaterials (NWs and NHs); thermodynamics model, dislocation punching model and molecular dynamic model, and also on the preliminary results of MSICD of two kinds of breast cancer cells under oscillating mechanical stress loading.
References
[1] Taya, M., Van Volkenburgh, E., Mizunami, M. and Nomura, S., 2016, Bioinspired actuators and sensors, Cambridge University Press.
[2] Amos, W.B., 1972, J. Cell. Sci., 10, 95-122.
[3] Katoh, K. and Naitoh, Y., 1994, J. Exp. Biology, 189, 163-177.
[4] Misra, G. Dickenson, R.B., Ladd, A.J.C., 2010, Biophysical J., 98, 2923-2932.
[5] Anelli, P.L., Spencer, N., Stoddart, J., 1991, J. Am. Chem. Soc., 113 (3), 5131-5133.
[6] Livoreil, A. Dietrich-Buchecker, C.O., Sauvage, J.P., 1994, J. Am. Chem. Soc.,116(20), 9399-9400.
[7] Koumura, N., Zijlstra, R.W., Delden, R.A. van, Harada, N., Feringa, B.L., 1999, Nature, 401(6749), 152-155.
[8] Taya, M., Xu, C., Matsuse, T., Muraishi, T., 2017, J. Appl. Phys., 121, 154302.
