Studies on Photothermal Effect in Nanofluidic Channel Toward Ultrasensitive Detection of Nonfluorescent Molecules Using Differential Interference Contrast Thermal Lens Microscope

H. Shimizu, K. Mawatari, T. Kitamori
The University of Tokyo, JP

Keywords: nanofluidics, photothermal spectroscopy


Absorption spectroscopy in nanofluidic channel was investigated for ultrasensitive detection of nonfluorescent molecules in nanospace. Recently, chemical analysis systems have been rapidly miniaturized from microspace to nanospace, which requires ultrasensitive detection of a broad range of molecules. Therefore, we have previously developed differential interference contrast thermal lens microscope (DIC-TLM) utilizing absorption and thermal relaxation (photothermal effect) for nonfluorescent molecules. Furthermore, the detection limit of the DIC-TLM was verified to be ~100 molecules level. However, heat transfer between the sample and nanochannel has remained as a problem to optimize its sensitivity. In this paper, photothermal effect in nanochannel has been studied using computational and experimental method. This paper will greatly contribute to creation of novel nanofluidic devices because the DIC-TLM is the first candidate to measure absorbance in nanospace.