Research On Olfactory And Gustation Biosensor Based On The Technology Of Genetic Engineering

The olfactory system of animals is an extremely acuminous chemistry sensor.It combines olfactory epithelium recognized the specific odor molecules which transferred the external odor stimulation to the olfactory cortex of the brain through olfactory bulb.This response and transmission process has a high sensitivity and specificity.The detection of odor molecules in vivo is mainly based on patch clamp technology and optical imaging technology.The patch clamp technology requires high operation skill,and has certain limitations on recording a large number of neuron group signals.Optical imaging technology is relatively lower in accuracy,and the background noise is relatively larger.Our research group has firstly proposed the concept of in vivo implantable biological electronic nose.The olfactory system of Sprague-Dawley(SD)rat was used to detect odor molecules and analyze neural response signals of olfactory bulb,so as to preliminarily classify and recognize odor molecules.In vivo implantable electronic nose can record the response signals of multiple neurons to odor molecules at the same time by using multi-channel electrodes.The biomimetic olfactory and gustatory sensor in vitro mainly composed of two parts,the first part is the sensitive element,mainly included the olfactory and gustatory receptor cell and the specific receptor protein.The other is the secondary transducer that can get the target detection and response produced by the sensitive element and make physical chemical signals easier to handle and analysis,such as electrical signals,such as impedance changes.Finally,the sensor and the signal processing related electronic circuit and instrument part are combined to form a complete detection system,so these bionic olfactory taste sensors have some unique advantages of the biological olfactory system,such as high sensitivity,low detection limit,good selectivity and so on.The main work and innovations are listed as following:1.This paper first introduced the concept of biomimetic olfactory and gustatory sensors and summarized the development status of the biomimetic olfactory and gustatory sensor in recent years.The development of biomimetic olfactory and gustatory sensor is mainly described from two aspects:in vitro biomimetic and in vivo electronic nose.Then the structure of olfactory system,cell differentiation and olfactory information transmission of olfactory sensory system were analyzed.The olfactory conduction mechanism about the main olfactory system was emphasized from cellular level and molecular level,also represented the intracellular conduction mechanism of cell of different kind of olfactory sense receptors,the function of different kind of cells in olfactory bulb and their projection in cerebral olfactory cortex.2.In this paper,an in vivo implantable olfactory electronic nose system model is proposed and the signal analysis of two different air supply modes,namely,long time continuous and short time intermittent air supply.Because of the synaptic connection between mitral cells and olfactory sensory neurons in the olfactory bulb and the synaptic connection between mitral cells and granulosa cells,the response of mitral cells to odor molecules has two different patterns,namely excitatory response and inhibitory response.The connection between each mitral cell and the olfactory sensory neurons with specific olfactory receptors lead to the fact that the mitral cells have certain specificity in the corresponding odor molecules.Through the analysis of the odor response signals,the specificity of the response is found.3.In this paper,in vivo biological electronic nose based on transgenic mice and brain-machine interface technology was designed,which overcame the disadvantages of early detection and used the fluorescence expression of transgenic mice to achieve fixed-point implantation of in vivo biological electronic nose,greatly improving the specificity and repeatability of odor detection.MEA silicon electrode can record the changes of extracellular electric potential of M72 olfactory sensory neurons of awake mice to different odor stimuli in real time for a long time.M72-IRES-tauGFP transgenic mice can be used as an indicator target to assist the implantation of electrodes due to their advantages in GFP protein expression.Experimental results show that the system has high sensitivity and stability in detecting and identifying odor molecules.In terms of detection of specific odor,electronic nose in vivo has a high specific response to odor molecules containing benzene rings.In explosive detection,the minimum detection limit can reach 10-5 M.4.This project is the first time to realize the simultaneous detection of smell and taste model.Human neuroblastoma cell line SH-SY5Y cells,which have been induced and transfected with receptors in vitro,are used as sensitive components to recognize odors,bitterness and toxicity.Using genetic engineering cells has a bitter taste and olfactory receptors at the same time,combined with MEAs sensors and cell impedance sensor for the secondary sensor,by recording specific odor molecules and bitter molecules caused by the activation of G protein coupled receptors on the cell membrane signals,and cell morphology change,proposed versatile bioengineered cell-based biomimetic sensor for the first time.At the same time,the cell impedance sensor can also detect the toxic effects of bitter substances on cells at high concentrations.