A peristaltic pump-based apparatus for capturing circulating tumor cells (CTCs) from blood is provided that includes a feedback control architecture that uses models of pump operation and measures of internal pressure fluctuations of the pump (e.g., in the form time-varying and/or position-dependent pressure oscillation data) to adjust pump operating characteristics that smooth pump operation, thereby improving viscosity and consistency of fluid flowing through the pump to a connected microfluidic capture device.

Provided herein is a system for delivering a therapeutic composition to a patient, including: a container configured to hold a therapeutic composition; at least one powered drive in operative connection with the container; a plurality of sensors including at least two of (i) a pressure sensor, (ii) a flow sensor, (iii) a counting sensor, (iv) a site sensor, (v) a temperature sensor, (vi) a chemical sensor, and (vii) at least one physiological sensor; and at least one processor programmed or configured to receive the data from the plurality of sensors and, control the at least one powered drive to inject the therapeutic composition into the patient at a desired flow rate whose magnitude depends on the data received from the plurality of sensors.