The project for the development and delivery of a fully automated microdialysis system with the implementation of an electrochemical sensor for the online monitoring of biologically active compounds was implemented in cooperation with the Theoretical Institutes of the Faculty of Medicine of Palacký University in Olomouc.
The microdialysis system consisted of three main parts:
- infusion dose dispenser (microdialysis pumps)
- evaluation unit
- detection flow cell
The infusion dose dispenser was made up of a casing containing the control electronics, a module for wired and wireless communication with the service PC or tablet, the mechanical part of the infusion dose dispenser, a stepper motor, a mechanical solution to the conversion of the propulsion power from the stepper motor into the driving piston system, and the actual driving piston. The driving piston was complemented with an extension kit for the positioning of a wide range of Hamilton injections from which the infusion solution was directly administered to the whole system.
The thoughtful mechanical design of the dose dispenser and the application of an internal stepping of the pump secured the actual ability of continual dosing within a range from 0.1 µl/min to 10 ml/min with the use of 5ml-volume syringes. The use of smaller syringes (2.5, 1, or 0.5 ml) could achieve very good results of continual dosing even at lower perfusion speeds.
The driving piston was furnished with a syringe piston detection function enabling, to move the piston to its working position, the use of much higher speeds and, thus, make work with the dose dispenser much more effective and faster.
The evaluation unit was made up of a special-design casing containing the control and evaluation electronics for supplying the detection flow cell with power, for converting and evaluating the measured signals, and for the communication with the control PC.
The detection flow cell was made up of a special-design casing with an microelectrochemical sensor suitable for in vivo analysis and monitoring of NO and other biologically active compounds. The power supply output from the microelectrochemical sensor was detected through an inbuilt potentiostat and, after amplification, was sent to the evaluation unit of the microdialysis system.