Peristaltic piezoelectric micropump system for biomedical applications.

This study presents a peristaltic piezoelectric micropump system to transport deionized water and whole blood, and deliver phosphated buffered saline (PBS) into the vein of a rat, thus simulating insulin injections for diabetes. The proposed system comprises a micropump, a 12 V battery, an ATmega 8535 microprocessor, a 12-180 V DC-to-DC converter based on transformerless technology, three differential amplifiers, an IC 7805, a phase controller, an A/D converter, a keyboard and an LCD module. The system can generate step-function signals of the 3-, 4-, and 6-phase actuation sequences with voltages of up to 228 Vpp (+/-114 V) and frequencies ranging from 10 Hz to 100 kHz, as the inputs for the pump. It is portable and programmable with a package size of 22x12.8x9 cm. Additionally, a protocol of the PEOU (N-(triethosilylpropyl)-O-polyethylene oxide urethane) coating is developed to form a self-assembly monolayer, thus increasing the hemocompatibility of the micropump, and keeping blood flowing smoothly through the micropump without blocking. This study performs the circuit testing and fluid pumping, and reveals the effects of actuation sequences and liquid on pump performance. The flow rates for pumping DI water and whole blood are 16.6-121.6 microl/min and 8.6-50.2 microl/min, respectively when the voltages are changed from 80 Vpp (+/-40 V) to 140Vpp (+/-70 V). And the maximum backpressures are 3.2 and 1.8 kPa for DI water and whole blood at 150 V(pp) (+/-75 V), respectively. The mean artery pressure (MAP) and heart rates of the rate are 63-69 mmHg and 266-279 beats/min, respectively, throughout the injection process, indicating an insignificant change in physiological reactions of rats.