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The need for simultaneous data recording from multiple channels and synchronization of correlation data processing in conventional patch-clamp on microelectrode arrays / chips with many data capture points corresponding to single channel ionic kinetic processes of individual cells leads to the idea that adaptive variation of the local potential registration conditions in multichannel devices without signal preprocessing in real time is impossible. Moreover, the advisability of direct registration coupling with the model realization for kinetic identification of the process during patch-clamp can be realized only in case of their synchronization. We propose here such a measurement system. Using MATLAB / SIMULINK we provided the signal recording to the sound card via a specially designed converter. The ion channel models used for comparison with the really obtained kinetic data were to operate in real time. It was shown that with the input unit from the audio input) the model operates in real time; in alternative registration schemes it was also possible to achieve a real-time mode in Windows by intercepting the interrupts from the processor. However, a sound card possesses a limited number of channels, which contradicts the idea of multi-channel data registration in conventional patch-clamp methods from arrays, and thus a hardware realization of multi-channel data acquisition and processing in real time irrespective from a sound card or an audio-input hardware emulation is required. There is a known «SIMULINK REAL-TIME» technology, based on computers like «xPC TargetBox» connected to the Windows-terminal operating as a host machine with a preloaded configuration MATLAB + SIMULINK (+ xPC Target) for actuator control and post-processing of data obtained from the sensors with the interface commutation through analog-to-digital converting units to the real time target machine / targetbox with the latter provided with a real time operating system (RTOS) like FreeDOS and xPC Target kernel, a kernel-level package transfer utility and a driver package xPC Target. As a consequence the above configuration allows to obtain maximum information from the experimental runs with the real-time data processing. We propose to apply this approach for the implementation of multi-channel conventional patch-clamp. For this purpose the registration channels should be commutated through the conversion units to the real-time machine interfaces. The technical implementation of this principle is not a significant problem, but varies depending on the target real time computer. Thus the "Modular" model in its standard version has 7 slots for input-output modules, in a minimal (small) modification - 6 and in the extended (large) one - 13. The modification type depends on the required number of input-output modules determined by the nomenclature of labs-on-a-chip / electrode matrix, and, consequently, by the studied samples. Furthermore, the connection of the general-purpose input-output modules is possible through RS232 / 422 / 485 (up to 115 kbit / с), commonly used for interfacing the host machine and the target computer. We have also tested a compact "Mobile" model with SPP / EP / ECP - IEEE1284 parallel port as a real machine, but it is somewhat inferior in performance to the stationary modification, and thus can not be recommended for massively work. n order to facilitate the user interaction with the system for biologists without special computer skills in MATLAB or SIMULINK and those who prefer not to deal in real time technologies, a special software shell was designed - an autonomous graphical user interface with the GUI in an MATLAB independent window. Despite the fact that as a result of the above procedure the total size of the software increases by some hundreds of megabytes as compared with the code file size (due to the necessity to transfer the corresponding libraries to the PC without preinstalled MathWorks), the control ease for the operator unfamiliar with high-level programming fully covers this drawback.
№ | Имя | Описание | Имя файла | Размер | Добавлен |
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1. | Полный текст | Conventional Patch-Clamp Techniques For Multi-channel Lab-On-A-Chip Signal Registration Using Real Time Target Machine Interfaces and in situ Real-Time Digital Signal Processing and Modeling | Conventional_patch-clamp_techniques_for_multi-channel_lab-o… | 81,9 КБ | 3 декабря 2014 [gradov] |