| Summary: | 碩士 === 國立臺灣海洋大學 === 光電科學研究所 === 98 === In this thesis, we present the studies of using surface enhanced Raman spectroscopy (SERS) to measure and analyze the glucose concentration in human blood. Our method is based on the following procedures: (1) High-aspect nanochannels of anodic aluminum oxide (AAO) substrates are used to filter blood cells and large biomolecules in whole blood sample. The 200nm-diameter and 200m-long AAO channels can filter the blood and exclude the interference of fluorescence and other complicated Raman signals of large proteins. (2) The filtered blood sample is then covered on the backside of the AAO substrate, which is coated with a nanometer thickness of silver film. The silver coated AAO surface provides metallic nanostructures that can greatly enhance the Raman signals of the filtered blood due to the SERS effect.
In this method, only several micro-liters of the blood sample is required. This quantity is suitable for obtaining blood samples from the blood collection needle. With few blood amounts and the AAO-SERS substrate, we got different Raman intensities from different thickness of silver and gold nanostructures by using a 780 nm laser. The optimal condition for SERS on a 200-nm-diameter AAO substrate is silver film with 10 nm thickness. We confirmed that the SERS signals at 1133cm-1 and 494cm-1 can be used to indicate the glucose concentrations. We found positive correlation between the change of SERS signals and the concentration of glucose. The detectable glucose concentration is in the range between 60mg/dl to 360mg/dl, which is suitable for the point-of-care application of the diabetic.
From the measurement, we also found that SERS signals were strongly dependent on the preservation of the blood samples. The Raman signal at 725cm-1 which is related to the Adenine was greatly affected by the preservation ways of blood samples. For room-temperature preservation, the 725cm-1 peak significantly increased with time. For 4oC condition, the change of 725cm-1 peak was small. This 725cm-1 SERS peak may be used to indicate the healthy condition of the blood sample.
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