Targeted Local Delivery via Fiber‐Embedded Flexible Microchannels Integrated with Film‐Based Implantable Probes

Abstract This study presents the development of a fiber‐embedded drug‐delivery channel for implantable microprobe applications, marking the first functional drug delivery system based on flexible liquid crystal polymer (LCP) probes. The innovative design integrates fibers to create a monolithic probe that enables site‐selective drug delivery and electrical stimulation/recording with minimal increase in device thickness. The fabrication process leverages monolithic thermal bonding, eliminating complex patterning and etching steps. Kevlar fibers are sandwiched between LCP film‐based microelectrode array (MEA) probes, facilitating both active and passive fluid transport via gaps around the fiber bundle and capillary wicking within the fiber bundle itself. A custom jig and specific thermal lamination process are developed to bond electrode‐patterned LCP films with fiber‐containing films, preserving the integrity of the fragile MEA during fabrication. The fluid transport properties of the channel are characterized under wet and dry conditions to determine capacity and maximum limits. MEAs with 64 electrodes are fabricated, and their electrical impedances are measured at 1 kHz. The integrated device is successfully implanted into a mice brain, and the delivery of microliter‐range chemicals is experimentally verified.