Polymeric Valves for Controlled Drug Delivery
Background: Biochips can be used in vitro or in vivo to deliver small, controlled amounts of chemicals or other molecules at controlled times and rates. Current delivery release mechanisms include electrochemical dissolution of thin anode membranes covering microreservoirs filled with drug. The metal valves, which are irreversible, consist of thin suspended non-porous layers that can be electrochemically dissolved or disintegrated by water electrolysis. Another mechanism involves sphincter configuration valves made of a blend of redox polymer and hydrogel. The blend is electropolymerized within an array of holes, which open and close corresponding to the shrinking and swelling of the polymer actuator. Neither method has all the following features: high diffusion efficiency; quick response; reversible open and close; minimum leakage in the closed position; low power consumption; and biocompatibility. Technology: Researchers at the University of California have developed a micro- release technology with the aforementioned features. The method relies on micro reservoirs covered with polymer based valves which serve as the gates to these reservoirs. The valve is a layered structure made in the shape of a flap anchored on one side of the reservoir opening. The substrate which consists of one or more reservoirs could be any structures facilitating the actuation and release, like a flat surface, or a hollow cylinder structure.
In contrast to the irreversible membrane valves system in the past, the reversibility of this invention dramatically elongates the life time of the whole system. Less than 1 actuating volt is required during the manipulation of release process and no energy needed to hold the valve in any desired position, which makes the invention consume much less energy than an electrochemical corrosion or thermal actuation approach. Compared to the sphincter configuration valves, the invention has less leakage in the closed position and is more biocompatible due to the materials adopted. In the invention, flapping the bilayers back and forth will help to create convection and help induce a more efficient transport of the drugs from the reservoirs. Application: The applications are not limited to drug delivery. Any liquids or gases could be released for any purpose. For example, releasing some of the gases contained in reservoirs will help change the buoyancy and adjust the position of a solid system in a liquid environment. Covering any expensive or backup devices and components like sensors for protection is another use.
Type of Offer:
« More Biotech Patents