Minimally Invasive Technique Based on Ultraslow Ultrafiltration To Collect and Store Time Profiles of Analytes

A device is described to collect and store continuously time profiles of analytes over periods of 24 h suitable to sample freely moving individuals (humans and animals). The device consists of a hollow fiber ultrafiltration probe, a long capillary and a nonmechanical unit (a disposable medical syringe) driven by vacuum to withdraw fluid. The principle is that at low rates (<100 nL/min), sample fluid is collected through the ultrafiltration probe into the capillary. A time resolution of less than 5 min over a 24-h collection and storage period was achieved for lactate and glucose. To illustrate an in vivo application, devices were fixed under the wing of freely moving broiler chickens, with subcutaneous or intravenous probe placements. The device can be produced as a disposable, and it may become applied for ex vivo and in vitro monitoring.