Fundamental research on design of nano-device using self-oscillating gel

作为一种新型的仿生聚合物，我们一直在利用振荡化学反应来研究具有自振荡功能的聚合物。我们成功地利用Belousov-Zhabotinsky(BZ)反应开发了一种新型的自振荡聚合物和凝胶。自振荡聚合物由聚N-异丙基丙烯酰胺(PNIPAAm)组成，其中Ru(Bpy)_3作为BZ反应的催化剂。在反应物(丙二酸、溴酸钠和硝酸)的共存下，聚合物在没有外部刺激开关的情况下，经历了自发的循环不溶变化或溶胀-脱胀变化(在凝胶的情况下)。为了使聚合物在生理条件下在不使用非生物相关的BZ底物的情况下发生自振荡，我们一直在尝试构建一种内置系统，其中将有机酸以外的底物加入到聚合物本身中。作为第一步，丙烯酰胺-2-甲基丙烷…在聚(NIPAAm-co-Ru(Bpy)_3)中引入了更多的磺酸(AMPS)作为pH控制点。作为下一步，我们尝试将氧化剂引入聚合物中。方法将带正电基团的丙烯酰胺丙基三甲基氯化铵(MAPTAC)引入聚(NIPAAm-co-Ru(Bpy)_3)中，作为阴离子氧化剂(溴酸根)的捕获点。通过离子交换将溴酸根离子引入含MAPTAC的聚合物中。使用该共聚物，只有在有机酸存在的情况下才能实现自振荡。为了合成一种在生理条件下工作的具有自拍功能的人工生物机器，我们开发了另一种可由ATP分解的化学能驱动的自振荡凝胶。以肌酸激酶为固定化基团，制备了含磷酸基团的阴离子聚合物凝胶。当凝胶浸泡在ATP溶液中时，凝胶中的酶反应发生，钙离子浓度周期性变化。因此，凝胶会自主地重复膨胀和消胀。较少

As a novel biomimetic polymer, we have been studying the polymer with an automonous self-oscillating function by utilizing oscillating chemical reactions. We succeeded in developing a novel self-oscillating polymer and gels by utilizing the Belousov-Zhabotinsky (BZ) reaction. The self-oscillating polymer is composed of poly(N-isopropylacrylamide) (PNIPAAm), in which Ru(bpy)_3 is incorporated as a catalyst for the BZ reaction. Under the coexistence of the reactants (malonic acid, sodium bromate, and nitric acid), the polymer undergoes spontaneous cyclic soluble-insoluble changes or swelling-deswelling changes (in the case of gel) without any on-off switching of external stimuli. To cause the self-oscillation of the polymer under physiological condition without utilizing non-biorelated BZ substrates, we have been attempting to construct the build-in system where the substrates other than organic acid are incorporated into the polymer itself. As the first step, acrylamide-2-methylpropanes … More ulfonic acid (AMPS) was incorporated into the poly(NIPAAm-co-Ru(bpy)_3) as the pH-control site. As the next step, we have attempted to introduce the oxidizing agent into the polymer. Methacrylamidopropyltrimethylammonium chloride (MAPTAC) with a positively charged group was incorporated into the poly(NIPAAm-co-Ru(bpy)_3) as a capture site for an anionic oxidizing agent (bromate ion). The bromate ion was introduced into the MAPTAC-containing polymer through ion-exchange process. By using the copolymer, self-oscillation only in the presence of organic acid was achieved. To synthesize an artificial biomachine with self-beating function which acts under physiological condition, we have developed another self-oscillating gel that can be driven by chemical energy of ATP decomposition. Anionic polymer gel with phosphoric groups, in which creatine kinase was immobilized, was prepared. When the gel was immersed in the ATP solution, the enzymatic reaction occurs in the gel and the concentration of calcium ion changes periodically. As a result, the gel repeats swelling and deswelling autonomously. Less