| Due to accelerating pace of life,more and more people suffer from diseases of the gastrointestinal. And Helicobacter pylori colonizes the mucus layer of the human stomach is the culprit for many gastrointestinal diseases. So far, the treatment of gastrointestinal diseases caused by Helicobacter pylori mainly through drug sterilization to inhibit bacterial infection. But drug sterilization eradication rate in clinic is low. In addition, drug resistance of bacteria become stronger along with the abuse of antibiotics.Blue light sterilization as a physical sterilization method, has the advantages of high efficiency, safety, no drug resistance and so on. In vitro and clinical experimental results shown that the specific wavelength of blue light can effectively kill Helicobacter pylori with high eradication rate. However, this technology is currently limited to clinical experiments for gastrointestinal application. Moreover, the phototherapy equipments have many deficiencies, such as large volume, invasive, patient discomfort. A miniaturized blue light sterilization technology based on light-emitting diode(LED) is addressed in this thesis, and a micro therapy device is designed. And the design changes the way for blue light sterilization to kill the Helicobacter pylori in human gastric parasitic area and makes it noninvasive, smaller in size. The main contributionsof this thesis are shown as follows:1. Fasting phase gastric area phototherapy model is discussed and effects of gastric motility are analysed. Through the analysis of the structure and motions of gastric fasting period, ideal phototherapy model for gastric area and design of light source are argued. And the light source for phototherapy is simulated as well.2. A micro device for blue light sterilization based on LED is designed. The micro sterilizing device is mainly constituted by LED phototherapy module, pH sensor module, main control and wireless communication module, battery and power management module.The device adopts a solution based on pH sensing to start and stop phototherapy work. By measuring the pH and tracking the position, the control of the state is realized3. The pH sensing module is aspecial emphasis the device with important functions. A number of experiments are conducted to test the measurement accuracy. With the supporting of experiment data, the measurement curve is fitted. The response time of pH sensor and start-stop function are tested. The performances completely satisfy the requests of the design. In order to improve the ability to resist interference and the measurement accuracy, a de-noising method based on improved ensemble empirical mode decomposition by automatic reconstruction is proposed.4. Several sets of power tests are measured to verify whether the device meets the design requirements. The efficiency of phototherapy module in different driving current and the efficiency of the system with different output powers of phototherapy module are tested. The power consumption of each function module is tested as well. The results shown that the device meets the technical specifications.The blue light sterilization technology studied in this thesis is mainly tagerted to kill the gastric Helicobacter pylori in the gastric fasting period and effect a cure. It performs as a noninvasive micro device which has the preponderance of safety and efficiency. Further research and perfection of this blue light sterilization technology will greatly improve the value of blue light sterilization phototherapy in clinical application. |
