Fundamental study of measurement of low concentration hydrogen sulfide in sera using carbon nanotube

Abstract

The study presented in this thesis was aimed to gain the fundamental knowledge regarding the mechanism of H2S measurement in sera by using carbon nanotubes (CNT) and fluorescence response. Characterization techniques such as Raman spectroscopy, X-ray absorption spectroscopy (XAS) and confocal laser scanning microscopy (CLSM) were employed to achieve this goal. The model system used for this study was composed of H2S, distilled water, two major serum proteins (albumin and globulin), serum, hemoglobin, and CNT.

The results of this study showed that: (1) Two major serum proteins (albumin and globulin) are physically adsorbed on the sidewall of the CNTs; while H2S is adsorbed on the defect site of the CNTs. (2) Presence of the proteins on the CNTs did not affect the CNT’s adsorption of H2S. (3) Using CLSM with the incident wavelength of 514 nm and the emission wavelength of 530 to 580 nm to acquire the fluorescence response of the H2S adsorbed on the CNTs is a reliable approach to measure H2S in sera. (4) Single-wall carbon nanotubes (SWNTs) outperform multi-wall carbon nanotubes (MWNTs) in measurement sensitivity. (5) Presence of hemoglobin in a H2S solution did not affect the measurement of H2S with CNTs and CLMS.

The study described in this thesis has provided new knowledge of the interaction behaviors of CNTs with H2S and major proteins in sera along with the mechanism which governs these behaviors. Such knowledge is very useful to further advance the CNT approach to sensing H2S in sera and water solution and to further extend the approach to sensing H2S in other mammalian tissues such as blood.