카본나노튜브와 금속 나노입자를 이용한 전기화학 (바이오)센서의 개발

Abstract

단일막 탄소나노튜브는 뛰어난 전기적, 기계적, 열적, 광학적 성질을 바탕으로, 최근 전극 재료로 각광을 받고 있다. 특히 탄소나노튜브의 우수한 광학투명도와 전기전도도를 기반으로 한 박막 형태의 전도성 투명재료로서의 적용은 전자공학, 촉매 및 센서 등에 널리 응용되고 있다. 탄소나노튜브를 전극으로 이용한 센서는 예전부터 사용해온 탄소 전극보다 더욱더 좋은 감도, 낮은 검출 한계와 빠른 전자전달 특성을 나타낸다. 또한 탄소나노튜브는 금속 나노입자와의 결합을 통해 낮은 전압에서 바이오/케미컬 분자의 환원반응 및 산화반응을 검출할 수 있게 되고 전기화학적 감도를 향상시키는 전기화학센서 개발의 가능성을 제시하였다. 본 연구에서 우리는 탄소나노튜브와 금속 나노입자를 이용하여 전기화학센서를 개발하였다. 우선, 전기화학 증착법을 이용하여 탄소나노튜브 기판 위에 환원제와 보호제 없이 입체적인 꽃모양의 백금 입자를 제작하였다. 백금 입자의 형태와 크기는 가하는 전압과 감광성 고분자의 패턴크기에 따라 조절이 가능하고 백금 입자가 패턴된 탄소나노튜브 필름은 전기화학적 센서로 적용하여 메탄올, 에탄올과 혈당을 측정하였다. 또한, 탄소나노튜브 필름을 마크로플루이딕 시스템에 접목시켜 금속 입자를 합성하고 전기화학분석을 통해 실시간으로 타겟 물질을 측정하는 방법을 제시하였다. 금속 나노입자는 전기화학적 증착법을 이용하여 마이크로 플루이딕 칩안에서 원하는 위치에 합성할 수 있었고 전기화학적 촉매물질로 사용하여 혈당과 중금속 물질 (As)의 함량을 정확히 측정하였다. 마지막으로, 탄소나노튜브 필름을 이용하여 마이크로플루이딕 pH센싱 칩을 개발하였다. 탄소나노튜브 박막은 작업전극으로 사용하는 동시에 pH 센싱 막으로도 사용되었다. 반도체 성질을 띄는 탄소나노튜브가 pH값이 변함에 따라 전자구조가 변하게 되는 특성을 이용하여 탄노나노튜브 작업전극과 Ag/AgCl 기준전극 사이의 전압차를 측정하는 방법으로 탄소나노튜브 필름을 pH 전극으로서의 활용도 제시하였다.|Single-walled carbon nanotubes (SWCNTs) have been the focus of significant research as promising electrode materials due to their remarkable electrical, mechanical, thermal, and optical properties. Due to these outstanding properties, SWCNT films have been employed as a new class of optically transparent and electrically conductive materials in electronics, catalysis, and sensing applications. CNT-based sensors generally have higher sensitivity, lower detection limits, faster electron transfer kinetics than traditional carbon electrodes. Moreover, the utility of novel metal nanoparticles to modify SWCNT electrode surface suggests the possibility of developing electrochemical sensors for bio/chemical molecules. The electrocatalytic properties of metal nanoparticles could decrease overpotential of some reductions or oxidations and further enhance the electrochemical responses greatly. In this dissertation, we developed electrochemical sensors based on SWCNT and metal nanoparticles. First, three-dimensional flower-like platinum particles were fabricated directly on flexible, transparent SWCNT films using a simple electrochemical method without the addition of a reducing or protecting agent. The size, shape, and uniformity of the platinum structures were effectively controlled by adjusting the applied potential, the pattern size of the photoresist polymer, and the deposition time. The as-prepared platinum particles-patterned SWCNT film was successfully used as an electrochemical sensor to detect methanol, formic acid and glucose. Furthermore, we report a novel method for in situ synthesis and integration of nanostructures within the microfluidic device and then real-time target monitoring by electroanalytical methods. Gold nanoparticles were directly fabricated on SWCNT electrode by electrochemical deposition at accurate position of working electrode within sealed microfluidic channels, and used as electrocatalytic materials for non-enzymatic glucose detection and suitable sensing surfaces for ultratrace As(III) detection. Finally, microfluidic pH-sensing chip was fabricated by integration with SWCNT film. The SWCNT thin film acted both as an electrode and a pH sensitive membrane. A pair of miniature SWCNT working electrode and Ag/AgCl reference electrode generated electrical potentials in solutions by electronic structure change in semiconducting SWCNTs responding to their pH level.; Single-walled carbon nanotubes (SWCNTs) have been the focus of significant research as promising electrode materials due to their remarkable electrical, mechanical, thermal, and optical properties. Due to these outstanding properties, SWCNT films have been employed as a new class of optically transparent and electrically conductive materials in electronics, catalysis, and sensing applications. CNT-based sensors generally have higher sensitivity, lower detection limits, faster electron transfer kinetics than traditional carbon electrodes. Moreover, the utility of novel metal nanoparticles to modify SWCNT electrode surface suggests the possibility of developing electrochemical sensors for bio/chemical molecules. The electrocatalytic properties of metal nanoparticles could decrease overpotential of some reductions or oxidations and further enhance the electrochemical responses greatly. In this dissertation, we developed electrochemical sensors based on SWCNT and metal nanoparticles. First, three-dimensional flower-like platinum particles were fabricated directly on flexible, transparent SWCNT films using a simple electrochemical method without the addition of a reducing or protecting agent. The size, shape, and uniformity of the platinum structures were effectively controlled by adjusting the applied potential, the pattern size of the photoresist polymer, and the deposition time. The as-prepared platinum particles-patterned SWCNT film was successfully used as an electrochemical sensor to detect methanol, formic acid and glucose. Furthermore, we report a novel method for in situ synthesis and integration of nanostructures within the microfluidic device and then real-time target monitoring by electroanalytical methods. Gold nanoparticles were directly fabricated on SWCNT electrode by electrochemical deposition at accurate position of working electrode within sealed microfluidic channels, and used as electrocatalytic materials for non-enzymatic glucose detection and suitable sensing surfaces for ultratrace As(III) detection. Finally, microfluidic pH-sensing chip was fabricated by integration with SWCNT film. The SWCNT thin film acted both as an electrode and a pH sensitive membrane. A pair of miniature SWCNT working electrode and Ag/AgCl reference electrode generated electrical potentials in solutions by electronic structure change in semiconducting SWCNTs responding to their pH level.