Fabrication and in vitro test of a microsyringe

This paper presents the fabrication of a microsyringe, which can be attached to the end of a microintravascular endoscope for drug injection. The syringe consists of a drug chamber and an actuator chamber, which are separated by a silicone rubber membrane. The drug chamber is filled with liquid drug by the membrane actuation caused by the vaporization and condensation of the working liquid in the actuator chamber. The liquid drug, less than 1 mu l, is ejected through a nozzle by the bubbles generated from the electrolysis of the working liquid. The syringe is fabricated by micromachining. The deflection of membrane for the each method has been measured. The liquid ejection volume has been measured from the video images captured during the electrolysis of the electrolyte. The average speed at nozzle from 0.1 to 1 s is about 0.14 m/s. Further, the successful operation of the microsyringe under the normal blood pressure was verified. (C) 2000 Elsevier Science S.A. All rights reserved.