Optogenetic Neural Prosthetic System Multi-physical Field Coupling Analyzing Model And Its Applications

Optogenetic neural prosthetics is an integrated novel technology which aims at fully or partly repairing of dysfunctional neural functions,which provides new scientific approaches to the therapy and repair of neural dysfunctions,disorders and neurodegenerative diseases.With optogenetic neural stimulation the core technology,optogenetic neural prosthetics is consisted of three entities which are neural prosthetics,optogenetics and opto-electro neural interface.These three entities are of quite different areas and backgrounds,so the development of optogenetic neural prosthetics is restricted by the lack of the full theoretic model as well as the simulation tool.In this thesis we research the optogenetic neural prosthetic system?OGNPS?multi-physical-field interacting model?OGNPS-MPCM?and its numerical analyzing program.We determine the core parameters of the model through experiments.By means of the model and the numerical analyzing program,we provide useful tool for design and optimization of the OGNPS.In the thesis we initially establish the OGNPS-MPCM including the sub-models of the lightwave circuits and light implantation,the optogenetic neural physiology and the OGNPS thermal effects,by analyzing the energy transfer and exchange of the physical fields in the optogenetic neural prosthetic process.OGNPS-MPCM is able to describe the whole process of energy transfer from the electric driving,to the optical stimulation,light-induced neural spiking and the systematic thermal energy eventually.Sequentially we research the numerical analyzing algorithms for OGNPS-MPCM.We define,and then code three types of numerical analyzing modules,10 solvers and their I/O parameters and data.In the following we demonstrate OGNPS-MPCM numerical analysis modules and optimize the calculating parameters through experimental work.We implement light penetration and lateral scattering experiment on rodent brain slice to investigate the difference of local optical stimulus profile in the tissue generated by different light emitting outlets on the optrode.The test results demonstrate the feasibility of the lightwave circuits and light implantation model and provide optimized parameters for optical analysis.We also implement a LED-based optrode thermal effect experiment.The test results demonstrate the feasibility of the thermal effect model and provide proper parameters for thermal analysis.Lastly we implement a ChR2 photocurrent experiment on optogenetic neurons.The test results demonstrate the feasibility of the optogenetic neural physiology model and provide proper parameters for neural physiological analysis.All the work above provide design and optimization tool for OGNPS research and development.In the next part we propose a passive adjustment method allowing spatial adjustment of local optical stimulus by changing the pattern at the output facet of optical waveguide.We analyze the feasibility of the method based on OGNPS-MPCM simulating program.The difference of neuronal response to adjustable optical stimulus is demonstrated,while the lateral resolution of local optical stimulus is improved.We also propose a passive adjustable optogenetic neural stimulating optrode based on SoS-PLC optical waveguide and obtain an optimized optrode with cross section of 17.8?m×7.8?m.The optimized optrode is fabricated and tested,the results show it is able to selectively stimulate TE₀₀,TE₁₀,TE₂₀ and TE₁₁ modes.Being coincident with simulations,clear adjustable mode pattern<5?m can be observed in the test and it is able to maintain for 100?m in the tissue.In the last part of the thesis,we propose a detailed scheme of active-implanting OGNPS consisted of GaN-?LED opto-electro-integrated optrode array,remote controller and implant controller.We fabricate and test the GaN-?LED to obtain its spectrum,light emitting radiation pattern opto-electro characterizations and external quantum efficiency.We propose that the core problem of active-implanting OGNPS and optrode is the trade-off between thermal and optical power.In the end we simulate a 8-stimulating-point GaN-?LED opto-electro-integrated optrode to obtain its best performance and optimized scheme under thermal restriction condition.