Flexible biosensors on spirally rolled micro tube for cardiovascular in vivo monitoring.

New flexible biosensors on a spirally rolled micro tube have been designed, fabricated and characterized for microcatheter-based cardiovascular in vivo monitoring. With this new microfabrication method, sensors, wires and circuits can be fabricated first on the flexible polymer substrate (Kapton film) and then rolled spirally to make micro tubes with different diameters. This approach provides a unique method for mounting multiple sensors on both the inside and outside the tube. So, the new spirally rolled polymer tube flexibly conceives physical, biomedical and physiological microsensors, elevating most problems arisen from wiring and assembling of microsensors in conventional microcatheters. As a demonstration vehicle, we fabricated glucose biosensors on the 25 microm thick Kapton film first, then the film was spirally rolled to make a polymer micro tube with the glucose sensors on the inside wall of the tube. To verify the performance of the spirally rolled glucose biosensor, we characterized it both in a planar unrolled and rolled conditions and compared their performances. The spirally rolled glucose sensors showed good performance in the typical glucose concentration range in human blood from 60 mg/dL to 120 mg/dL with different rolled diameters at different working temperature.