단일벽 탄소나노튜브로 기능화된 정전용량 기반 액면 감지 센서

초록

The demand for automated liquid handling systems equipped with high-precision pipetting technology is rapidly increasing. Among the various liquid level detection (LLD) technologies, capacitive LLD (cLLD) has been widely adopted, owing to its rapid response and biocompatibility. Therefore, developing highly sensitive cLLD electrodes is essential for enhancing the signal response at the air/liquid interface significantly. Herein, we describe a highly sensitive cLLD electrode modified using single-walled carbon nanotubes (SWCNTs) for high-precision liquid handling. This SWCNT-modified electrode achieved enhanced capacitive characteristics by optimizing the inter-electrode distance, because of minimized electrolyte resistance and accelerated charge transfer. Furthermore, the SWCNT-modified electrode exhibited superior charge-transfer properties compared to multi-walled carbon nanotube (MWCNT) and reduced graphene oxide (rGO)-modified electrodes, owing to its high aspect ratio and large surface area. In the performance evaluation, the SWCNT-modified electrode demonstrated an approximately 1.6 × higher capacitance change compared to bare electrodes, enabling highly sensitive LLD. The proposed cLLD technology is expected to advance the use of automated liquid handling systems in cell culture, nucleic acid analysis preparation, drug efficacy evaluation, etc.

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