Institute of Multidisciplinary Research for Advanced Materials, Tohoku University


LAST UPDATE 2021/05/09

  • 研究者氏名
    Researcher Name

    ダオ・ティ・ゴック・アン DAO Thi Ngoc Anh
    助教 Assistant Professor
  • 所属
    Professional Affiliation

    Institute of Multidisciplinary Research for Advanced Materials, Tohoku University

    マテリアル・計測ハイブリッド研究センター 有機・バイオナノ材料研究分野
    Materials-Measurement Hybrid Research Center, Organic-and Bio-Nanomaterials
  • 研究キーワード
    Research Keywords

    Inorganic Chemistry
    Polymer Chemistry
    Hybrid Nanoparticles
    Drug Delivery
Research Subject

Designing and Modification of Heterogeneous Nanoparticles for Biosensing Applications. Degradation and Stability of Highly Functional Protein Materials. 

研究の背景 Background

(1) Plasmonic metallic nanoparticles (NPs) have been explored extensively in terms of their fundamental and practical applications such as for optoelectronic devices, optical metamaterials, sensors, and solar cells, etc. Au and Ag as (nano) plasmonic metals have become very attracted because Ag provides high enhanced-Raman activity, while the Au provides excellent chemical stability and a great reactivity with sulfur containing biomolecules, which has inevitably leaded to the combination of Au and Ag in a single NP system.
(2) One of the most amazing things about natural spider silk is its unparalleled tensile strength in combination with extendibility, surpassing steel and rivaling even Kevlar [1]. The ability to manufacture and manipulate synthetic spider silk would lead to the development of many new materials that are lightweight but incredibly tough, finding use in the medical field, transportation and many other areas. While we can now synthesize spider silk at large scales and start to gain success over the spinning process of artificial fibers, there is still a lack in understanding for how to avoid degradation of the material in ambient conditions.

研究の目標 Outcome

(1) Au@Ag core@shell NPs were successfully synthesized with uniform morphology and tunable size, composition and plasmonic property, through a straightforward citrate reduction and the products don’t require complicated treatment process for further uses. Au@Ag core-shell NPs were demonstrated to have better chemical stability than pure Ag NPs and very high SERS activity. Moreover, Ag in the shell also could suppress the galvanic replacement reaction allowing the formation of double shell (Au@Ag)@Au NPs without any defects or gaps in the structure, due to the electron transfer effect from Au core to Ag shell.
(2) A multi-dimensional analysis were applied while analyzing the change in the physicochemical characteristics of the spider silk during the degradation. The results were traced using a statistical approach based on the spectral expression of correlation coefficients, to systematically obtain the overall alteration of spider silk during degradation in both compositional and conformational aspects.

研究図Research Figure

Fig. 1. STEM image of (A) Au@Ag NPs and Au@Ag@ Au double shell NPs; (B-D) EDS elemental mapping images of Au@Ag NPs. (Right) Illustration of electron transfer effect from Au to Ag in heterogeneous NPs. Fig. 2. (Top) Illustration of creation of Raman active NP assemblies and usage of NPs in SERS technique;
(bottom) Raman spectra of Au@Agx
[from bottom to top, x = 0.4, 1.0, 2.2, and 3.6 nm (blue curve)] and (Au@Ag3.6)@Au (red curve) NP
assemblies created by using ATT. Fig. 3. (Lower) A series of NMR spectra for recombinant spider silk degraded at 200 C under dry air and (upper) the corresponding correlation coefficient spectrum.

文献 / Publications

Polym. Degrad. Stab. 2018, 153, 37–46; Carbon 2018, 113, 109–117; Appl. Cat. A: Gen. 2018, 549, 60–67; Polym. Degrad. Stab. 2017, 144, 264–269; Polym. Chem. 2017, 8, 1049–1060; Sensors 2013, 13, 7813; Adv. Colloid Interface Sci. 2012, 185-186, 14–33; Appl. Phys. Lett. 2011, 99, 073107.