高分子 Vol.62 No.6
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特集 イメージングと高分子
展望 COVER STORY: Highlight Reviews
超音波セラノスティックス
Ultrasound Theranostics
丸山 一雄
Kazuo MARUYAMA
<要旨> セラノスティックス(Theranostics)とはtherapeutics(治療)とdiagnostics(診断)の両機能を有するシステムである。超音波造影ガスを封入したバブルリポソームは、超音波造影による診断のみならず、キャビテーションによる治療を可能とするセラノスティックス製剤として期待される。
Keywords: Ultrasound / Theranostics / Micro Bubble / Liposome / DDS / Gene Delivery
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両親媒性ブロックコポリマーを用いる腫瘍の可視化
Development of Tumor Imaging Agents Consisting of Amphiphilic Block Copolymers
三木 康嗣
Koji MIKI
<要旨> 両親媒性ブロックポリマーが形成する自己集合体は腫瘍集積性が高いため、腫瘍造影剤の母体として注目されている。造影剤分子の特性を活かす自己集合体を設計・構築することで、造影剤の性能を向上させることができ、高コントラストな腫瘍の可視化につながる。本稿では、最近の例を中心に高性能な高分子造影剤の開発について概説する。
Keywords: Tumor Imaging / Contrast Agent / Polymeric Self-Assembly / Amphiphilic Block Copolymer
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動的な自己集合性ナノ粒子によるタンパク質活性のシグナルOFF/ONイメージング
Detection and Imaging of Protein Activity with Dynamic Self-Assembling Turn-on Nanoprobes
高岡 洋輔・浜地 格
Yousuke TAKAOKA, Itaru HAMACHI
<要旨> 細胞や生物個体にはさまざまなタンパク質が存在し、その発現と分解が常に制御されて機能を発揮している。これらのタンパク質の動的な変化を、網羅的あるいは特異的に検出できる自己集合性ナノ材料が近年注目を集めている。本稿では、タンパク質の構造や活性を、シグナルのOFF/ONスイッチングで検出するナノ材料について、最近の研究を紹介する。
Keywords: Protein / 19F-NMR/MRI / Fluorescence / Imaging / Nanoparticle / Supramolecular Chemistry
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トピックス COVER STORY: Topics and Products
アプタマーを用いる化学伝達物質イメージング
Chemical Transmitter Imaging Using Aptamer Sensor
山東 信介
Shinsuke SANDO
<要旨> Nucleic acid aptamer is a functional biopolymer that can bind to target molecules. Because of high affinity and specificity to targets in water, there has been an attention on application of aptamers to biosensors. However, cellular application has been very limited. We have applied fluorescent aptamer sensors for molecular imaging of chemical transmitters, especially those working in brain. The fluorescent aptamer sensor, which was anchored in live cell surfaces, functioned as a biosensor for fluorescence imaging of chemical molecules at the cell surface. By using the cell-surface anchored fluorescent aptamer sensor, we achieved a real-time imaging of chemical transmitter dynamics released from rat astrocyte cells. This approach could expand the research field of aptamer biosensors.
Keywords: Fluorescence Imaging / Chemical Sensor / Chemical Transmitter / Aptamer / Cell Surface
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高分子MRI造影剤の開発研究
Developments of Macromolecular MRI Contrast Agents
唐澤 悟・古賀 登
Satoru KARASAWA, Noboru KOGA
<要旨> We report herein our approaches using macromolecules and assemblies carrying metal and organic spins as magnetic resonance image (MRI) contrast agents. Core-shell type hyperbranched polymers carrying manganese complexes (HPS200-8-MnDO3A-DEA), and lipophilic urenylbenzene derivatives (EgnCmU-TEMPO) and DNA oligomers incorporated stable organic radical, TEMPO, were prepared as macromolecular MRI contrast agents. A HPS polymer, HPS200-8-MnDO3A-DEA, was evaluated by in vivo MRI measurement and revealed to function as an MRI agent. EgnCmU-TEMPO derivatives having PEG and alkyl chains exhibited LCST phenomena in water and were found to have the relaxivity in response to heat and pH. Furthermore, TEMPO-DNA micelle locating TEMPO near a core of micelle was found to have the relaxivity higher than that for GdDOTA at 42 MHz and 1.0 T.
Keywords: MRI Contrast Agents / Maclomolecules / Manganese / TEMPO / Organic Spin / Relaxivity
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ナノサイズベシクル“PICsome”を用いた生体イメージングとナノ生理学の可能性
Development of Nano-Sized Polyion Complex Vesicle “PICsomes” and its Application to Bioimaging and Nano-Physiology
岸村 顕広
Akihiro KISHIMURA
<要旨> To gain more insights of structural and physicochemical features of sick parts in our body, we need to investigate our body from the nanoscopic viewpoint. Some appropriate tools are required for this purpose, or nano-physiology, particularly to visualize the affected part at the nanoscopic level. Recently, we have developed polyion complex vesicles “PICsomes” mainly based on the electrostatic interaction between oppositely charged block copolymers. Remarkable features of PICsomes were demonstrated, such as unilamellar structure with uniform thickness, tunable size over the range of 100-400 nm, easy loading of water-dispersible materials, semi-permeability, excellent blood circulation in mice, and so on. Detailed biodistribution of PICsomes with different sizes was examined in tumor-bearing mice. Critical size of nanocarriers (~150 nm) discriminating the permeability into normal and tumor tissues was determined by the use of long-circulating PICsomes as a ruler. This result clearly shows potential utility of PICsomes in the filed of “nano-physiology”, considering the compatibility of PICsomes with various bioimaging probes.
Keywords: Drug Delivery System / Block Copolymers / Vesicles / Polyion Complexes / Bioimaging / Nano-Physiology
 
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PEG修飾デンドリマーを利用したX線CT、MRI
X-Ray CT and MRI Using PEGylated Dendrimers
児島 千恵
Chie KOJIMA
<要旨> There are a lot of imaging techniques such as X-ray CT (computed tomography) and MRI (magnetic resonance imaging). Imaging agents with small molecular weight are rapidly excluded from the body, whereas macromolecular imaging agents are more useful. Dendrimers are synthetic globular macromolecules with well-defined structure, multiple terminal groups and inner space. Additionally, polyethylene glycol (PEG) modification to dendrimers is indispensable for biomedical applications. In this paper, X-ray CT imaging and MRI based on PEGylated dendrimers are shown. First, we prepared gold nanoparticle (Au NP)-loaded PEGylated dendrimers for X-ray CT imaging. Interestingly, Au NP has photo-thermogenic property, which is applicable to photothermal therapy. Thus, Au NP-loaded PEGylated dendrimers are useful in both, therapy and diagnosis, named theragnosis. Next, we prepared Gd-chelate-conjugated PEGylated dendrimers. This dendrimer shows higher MR signals than the chelate itself. Blood pool and heart were enhanced by the Gd-chelate-conjugated PEGylated dendrimer. Because some imaging probes can be attached to the dendrimers, dendrimers are potent multimodal imaging agents.
Keywords: Dendrimer / PEGylation / X-Ray CT / MRI / In Vivo Imaging
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グローイングポリマー Polymer Science and I: A Personal Account
たまには妥協せずに
Sometimes We have to Hold Our Ground
矢貝 史樹
Shiki YAGAI
<要旨> From my experience living and working with an Indian student for two months, I learned new discoveries elude us if we compromise our goals.
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高分子科学最近の進歩 Front-Line Polymer Science
天然ゴムのナノマトリックス構造と物性
Nanomatrix Structure and Properties of Natural Rubber
河原 成元
Seiichi KAWAHARA

<要旨> Nanomatrix structure, consisting of a dispersoid of a major component and a matrix of a minor component, was formed in natural rubber, after removal of all proteins from the rubber. It was found to be a unique nano-phase separated structure by both field-emission scanning electron microscopy equipped with focused ion beam (FIB-SEM) and transmission electron micro-tomography (TEMT). Dramatic increases in mechanical properties and proton-conductivity were associated with the formation of the nanomatrix structure. Based on the results, the nanomatrix of non-rubber components such as proteins and phospholipids was found to be inherently formed in natural rubber, in which natural rubber particles of about 1μm in average diameter were dispersed. It was proven that the nanomatrix structure played an important role in the outstanding mechanical properties of natural rubber. Some applications of the nanomatrix structure were shown for composites of natural rubber with inorganic fillers.
Keywords: Natural Rubber / Nanomatrix Structure / Nanomatrix / Proteins / Phospholipids / Latex / Terminal Units / Graft-Copolymerization

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