Modulation On Electrophysiological Function Of Neuron By Near-infrared Laser And Study Of The Optical Coherence Tomography Imaging Technology

Biomedical optics has become more and more important in both clinical and fundamental biological studies in recent years. Optical method is very suitable and important for bioengineering study due to its low damage, noninvasive and very good temporal and spatial resolution as an imaging tool. Therefore biomedical optics will be developed and used widely in biomedical engineering.This thesis is mainly focused on how does laser irradiation affect electrophysiological function of biological tissue and how to use the optical imaging method to monitor the changes of biological tissue. In order to study the electrophysiological function, a patch clamp technique was employed to monitor the function changes of the voltage sensitive sodium (Na) and potassium (K) channel under laser stimulation. In order to detect biological tissue structure changes, an Optical Coherence Tomography(OCT) technique was chosen to image in an endoscope way.The achievements of this thesis:A980nm low-power continues wave (CW) near-infrared laser was employed to stimulate the hippocampal neurons of SD mouse in vitro. By using a patch-clamp technology the electrophysiological function of neurons was recorded and analyzed by a PULSE software, which was provided by the Heka company. Furthermore the mechanisms of low power CW near infrared light stimulating neuron electrophysiology function was investigated from the perspective of both the whole cell Na current and single channel recording. The main mechanism of laser modulation was ascribed to photothermal effect.We designed and built a swept source OCT system and fabricated an intravascular OCT endoscope. Then the OCT system was integrated with fluorescence intensity imaging system and an integrated endoscope was designed for diagnosis of atherosclerosis plaque. With this integrated system we can obtain the cross section images of vessel wall and as well as bimolecular information together. In order to make this system more practical in clinical applications, a triple modalities imaging system was built. Ultrasound imaging system was combined together with the OCT and fluorescence dual modalities imaging system. Ex-vivo human coronary artery images demonstrated that this triple modalities system would be suitable for the early detection of atherosclerosis plaques.