Study Of A Novel Fluorescent Probe Based On Semiconductor Quantum Dots/Polymer Composites For Nitric Oxide Detection

Nitric oxide (NO) is one of the smallest and simplest biologically active molecules in nature with unique chemistry. NO is an important messenger molecule and regulates a variety of biological processes, such as the regulation of diverse physiological and pathophysiological mechanisms in cardiovascular relaxation, neverous transmission and immunological responses. Accurate and rapid detection of NO is of great significance for understanding these biological functions in the fields of the life science, preclinical medicine and clinical medcine. Fiber optic sensing technology is a newly developing detection method due to the high sensitivity, short response time, anti-electromagnetic interference, low cost, easy to operate and real-time detection. Fiber optic bio-sensors have been widely used in the fields of the environment monitoring, food industry, clinical medicine and biological engineering, which represent the development trend of a new generation of sensors. Fiber optic sensors were developed to monitor NO recently owing to the high sensitivity, short response time and in vivo detection.This thesis was financially supported by the National Natural Science Foundation of China (NO.50802069) and State Key Laboratory of Advanced Technology for Materials Synthesis and Processing (Wuhan University of Technolgoy)(NO.2012-KF-2). We synthesized CdS/PMMA nanocomposites and CdSe/PMMA nanocomposites as the NO sensitive materials. A novel fiber optic sensor for detection of NO was designed and quantum dots/polymer composites were used to detect NO. We studied its sensing properties. The main contents include:(1) CdS/PMMA nanocomposites were synthesized by a novel method and characterized by XRD, IR, UV-Vis, DSC, TEM etc. The sensing mechanism between CdS/PMMA nanocomposites and NO was studied. The standard curve of CdS/PMMA reacted with NO was obtained.(2) CdSe/PMMA nanocomposites were synthesized by the blending method and characterized by XRD, IR, UV-Vis, TEM etc. The sensing mechanism between CdSe/PMMA nanocomposites and NO was studied. The result showed that the fluorescence intensity of CdSe/PMMA was sensitive to NO.(3) A novel fiber optic sensor was developed for determination of NO using CdSe QDs. The sensitive membrane was prepared from cellulose acetate (CA) embedded with CdSe QDs. Under the optimum experimental conditions, a liner calibration (R2=0.9908) range was from1×10-7to1×10-6mol·L-1with the detection limit of1×10-8mol·L-1. This result indicated that the sensor was suitable for NO detection in biological system.