BioLab F device is one of the modules of the distributed measuring system Biolab and is intended for measurement of 3 selected electrical, pressure or flow signals from experiments on isolated hearts of small animals.

BioLab system was designed for biosignal measurements in laboratory and experimental clinics. It consists of a set of intelligent sensors that are connected over the Ethernet network to a host PC working as a controlling and data processing unit. Each sensor contains specific measuring module for conditioning of signals from particular biophysical experiment and a controlling module based on Analog Devices ADμC812 microcontroller. 

BioLab-F device is used with the Langendorff measuring system and enables to measure triples of selected biosignals such as electrogram, blood pressure and drug dosage and to determine their required biophysical parameters. Programs for signal processing and evaluation include amplitude, shape, time and frequency or correlation analysis and were developed in the MATLAB environment.

The Langendorff measuring system is suitable for „in-vitro“ investigations on isolated hearts of small animals, such as rat, guinea-pig or hamster. It is used for evaluation of potential responses of myocardial cells evoked by pharmacological stimulation. For evaluation of biophysical parameters from the experimental setup, BioLab-F device is attached to electrical outputs of electrodes, blood pressure sensors and flowmeters of the above mentioned system and enables long time monitoring and digital recording of the measured experimental data and their subsequential advanced off-line processing.

BioLab-F device was designed as a 3-channel sensor and allows signal monitoring and recording in two modes:

• electrogram from the heart (ECG) and two pressure signals (ventricular pressure PS1 and pressure PS2) or
• electrogram from the heart (ECG), left ventricular pressure (PS1) and drug dosage (DD).

In the second case, the drug dosage signal DD is recorded instead of PS2 pressure and the third channel of BioLab-F device is switched from the pressure sensor to the output of a drop-type flowmeter. Sampling frequency for all three signals is 1 kHz or 500 Hz.

Controlling module of the BioLab F device is built around an ADµC812 microcontroller with necessary interface. To connect the sensor to the modular system over the Ethernet network, a RS232C to TCP/IP converter is used. To guarantee safety of the experiment, BioLab F module is galvanically separated from the Ethernet network by optical isolation. The module is powered by a Li-ion cell that allows several hours of uninterrupted operation. In practical applications, intelligent power management allows working time of the cell up to tens of days. The module can by operated also during the battery charging from the power line 230V / 50 Hz, eventually even from the power line (without using the Li-ion cell).

Graphical User Interface system for signal processing and analysis of measured signals was developed in Matlab environment. The results of signal analysis are automatically generated, their format can be modified by the user and inserted into a final protocol of the experiment. In signal windows, electrogram signal ECG, pressure signals PS1, PS2, their derivations or signal of drug dosage DD can be seen.               

As an example, it is possible to display selected part of ECG signal with its spectrogram, or three-dimensional projection of spectrogram PSD (t,f). Combination of these alternative displays can be used for more detailed study of signal dynamics and their characteristic features.

BioLab-F device was developed within a bilateral project for the Institute for Heart Research and is in use in the Institute of Experimental Pharmacology, Slovak Academy of Sciences.