Research On Cell Network-and Tis-sue-based Sensors For Spatio-temporal Analysis Of Olfactory Signals

Biological neural network is a huge and complicated system, which comprises abundant highly organized and interactional neurons. The neuronal electrical activities in the neural network take on distinctive spatio-temporal characteristics. Investigating the electrophysiological properties of multi-neurons in cell-networks or tissues is sig-nificant for the study of information processing and conduction in neural networks. With the development of micro-electro-mechanical systems (MEMS) technology, mi-croelectrode array (MEA) and field effect transistor (FET) array have developed rap-idly for their synchronously multi-channel measurement, presenting obvious advan-tages in the study of neural networks. Thereinto, the cell network- and tissue-based biosensors by combining multi-cells or tissues with MEA have gained extensive ap-plication, and become the important technique for spatio-temporal analysis of neuronal signals.In usual olfaction study, patch clamp recoding technique and optic imaging tech-nique are the primary electrophysiological measurement methods. Patch clamp tech-nique is not convenient for spatio-temporal analysis of neural network for it can not realize synchronous multi-site measurement. While, optic imaging technique has tox-icity on cells, so it is not fit for long-term measurement. With the characteristics of long-term, scatheless and synchronous multi-site measurement, MEA is used to build up the olfactory cell network- or tissue-based biosensors, which are of great impor-tance for acquiring and analyzing the olfactory spatio-temporal information. In the present study, using in vitro olfactory neurons and tissues as the sensing elements, we developed the cell network-based and tissue-based biosensors with MEA to investigate the spatio-temperal characteristics of cell networks and tissues, principally analyze the signals detected from each layer of the olfactory bulb.The major contents and contributions of this thesis are as follows:1. We profoundly studied the olfactory epithelium cell network-based and olfac- tory bulb cell network-based biosensor. With the spatio-temporal characteristics of electrophysiological under acetic acid, butanedione and high K+ stimulation analyzed, the detecting capability of the olfactory epithelium cell network-based biosensor was investigated. Results indicate that this cell network-based biosensor can distinguish the responses under different conditions and olfactory receptor neurons selectively re-sponse to odors. This research provides the experimental basis for designing the elec-tronic nose and exploring the odor discrimination mechanism. Using the OB neu-ron-based biosensor, we investigated the neural signal characteristics in the presence of different dosages of glutamic acid (Glu). Results showed that Glu can make the olfac-tory signals oscillate and amplify, which are the important characteristics of odor dis-crimination and signal processing.2. Due to self-beating of cardiomyocytes, we designed in vitro cardiac tis-sue-based biosensor. It was found that delay time is the important parameter of cardiac propagation analysis. Because MEA can realize multi-site synchronous measurement, we reviewed the action of cardiovascular drugs at different positions. This research is very significant to study novel tissue-based biosensor for target-administrating in clinic. This research provided the basis and effective method for designing the OB slice-based biosensor. In addition, the difference and characteristics of the cardiac tissue-based biosensor and the OB slice-based biosensors were also presented in the present thesis.3. An OB slice-based biosensor was developed for the first time, which is used to analyze the oscillation signals and information conduction in the each layer of the OB slice. According to mordality of OB and spacial distribution of signals, we found that the olfactory information was received in olfactory nerve layer (ONL) and glomerulus layer (GL), and transferred to mitral cell layer (MCL) and granule cell layer (GCL) through external plexiform layer (EPL), and then output from MCL and GCL. With cross-correlation analysis, we investigated the spatio-temporal characteristics of the responses before and after using Glu, and found that some biological contacts and synapses mediated by Glu receptor maybe exist between layers of OB slice. Moreover, results showed that different frequency oscillation appeared in the different layers of OB slice, which contains signal temporal property.