Abstract: Devices and methods are disclosed to provide hybrid, modular systems for the constitutive delivery of appropriate dosages of active factor to a subject and, in some instances, to specific anatomical regions of the subject. The systems include a cell reservoir containing living cells capable of secreting an active agent, which is preferably adapted for implantation within the body of the subject and further includes at least one semipermeable membrane, whereby the transplanted cells can be nourished by nutrients transported across the membrane while at the same time protected from immunological, bacterial, and viral assault. The systems further include a pumping means, which can be implantable or extracorporeal, for drawing a body fluid from the subject into the cell reservoir and for actively transporting the secreted biological factors from the cell reservoir to a selected region of the subject.

Abstract: Methods and devices are disclosed for the delivery of a neurotransmitter from an implanted, neurotransmitter-secreting cell culture to a target region in a subject. The cell culture is maintained within a biocompatible, semipermeable membrane which permits the diffusion of the neurotransmitter therethrough while excluding viruses, antibodies, and other detrimental agents present in the external environment from gaining access. Implantable cell culture devices are disclosed, some of which may be retrieved from the subject, replaced or recharged with new, neurotransmitter-secreting cell cultures, and reimplanted.

Abstract: Devices and methods for transmitting neural signals from a proximal stump of a transected nerve to a prosthetic apparatus are disclosed employing microelectrodes, preferably conductive fiber networks, capable of sensing electrical signals from a nerve and transmitting such signals to a prosthetic apparatus; and a semipermeable guidance channel disposed about the microelectrodes. The channels include an opening adapted to receive the proximal stump of a transected nerve, such that the channel promotes the growth of the stump and the formation of an electrical connection between the transected nerve and the microelectrode.

Abstract: Medical devices employing semipermeable materials, such as acrylic copolymers, polyurethane isocyanate, and other biocompatible semipermeable polymers, are disclosed for use as guidance channels in regenerating nerves. The devices can be formed by tubular semipermeable conduits adapted to receive the ends of a severed or damaged nerve. The tubular conduits define lumens through which axons can regenerate to restore motor and/or sensory functions. The guidance materials are chosen such that they are capable of allowing the diffusion of nutrients and other metabolites to the regenerating nerve site while excluding fibroblasts and other scar-forming cells. In particular, tubular channels which have a smooth inner surface and longitudinally oriented trabeculae result in significantly larger regenerated nerve cables and higher numbers of regenerated myelinated axons.

Abstract: A catheter including a support suitable for insertion into a body organ, a transducer carried by the support, the transducer including a flexible piezoelectric polymeric membrane, and a pair of surface electrodes mounted on the membrane, the support including a rigid portion defining a flexure cavity inside the catheter, the membrane being mounted on the rigid support portion to permit free flexing of the membrane into and out of the cavity, one surface of the membrane communicating with the cavity, the other surface of the membrane being exposed to the exterior of the catheter to receive and flex in response to pressure variations in the organ, and an electrical cable for transmitting from the electrodes to external circuitry electrical signals produced by said flexure.

Abstract: A cell culture device for use, e.g., as an artificial pancreas, featuring, in various aspects, a semipermeable tube wrapped about a spool and mounted within a cylinder to form a cell culture compartment; an inlet and an outlet strand of the semipermeable tube being wrapped to form alternating adjacent coils to provide improved convective transport; and the semipermeable tube being wrapped to form helical coils to provide improved conductive transport.

Abstract: A cell culture device for use, e.g., as an artificial pancreas, featuring, in various aspects, a tightly wound spiral tube snugly fit in a cavity to form a cell culture compartment, the spiral being eccentrically offset in the cavity to reduce the volume of the compartment, a sloped passage in the body with an end of the tube extending through the passage to the innermost spiral without bending sharply, the ends of the spiral tube communicating with ports on the same side of the body, and a wall of the cavity facing the spiral and being spaced from the tube to form an end of the compartment to provide for simplified cell loading.

Abstract: Methods and devices are disclosed for the delivery of a neurotransmitter from an implanted, neurotransmitter-secreting cell culture to a target region in a subject. The cell culture is maintained within a biocompatible, semipermeable membrane which permits the diffusion of the neurotransmitter therethrough while excluding viruses, antibodies, and other detrimental agents present in the external environment from gaining access. Implantable cell culture devices are disclosed, some of which may be retrieved from the subject, replaced or recharged with new, neurotransmitter-secreting cell cultures, and reimplanted.