A method of continuously regulating external gas pressure on a variable volume container for the delivery of fluids to a microfluidic device and analysis of particles based upon relative presence or absence of at least one particle characteristic. The system, which may include an electronic maintenance apparatus that may be in the form of a hand-held digital computer, allows a user to capture and store images, sound, andor error codes and related text or voice data and other information concerning the system or object being maintained. The actuator is based on an electrochemical cells and may be a conducting polymer based actuator. The invention may help reduce or eliminate the need for blood drawing, sending the sample to a blood lab and having to wait for a result.