Abstract:
The invention relates to a method of fabricating a microneedle array in a substrate, a drug delivery device comprising one or more microneedles extending upwards from the front surface of the substrate, the microneedles having a generally conical-shaped body defined by a plurality of surfaces sloping upwards from a relatively broad base to a tip, and one or more substances coating the microneedles, the one or more substances being operable to be administered to a patient, wherein the tips of the one or more microneedles are sufficiently sharp to penetrate an outer layer of the skin of the patient, and a method of administering one or more substances to a patient using the device.
Abstract:
The present invention provides a microneedle incorporating a base that is broad relative to a height of the microneedle, to minimize breakage. The microneedle further includes a fluid channel and a beveled non-coring tip. Preferably arrays of such microneedles are fabricated utilizing conventional semiconductor derived micro-scale fabrication techniques. A dot pattern mask is formed on an upper surface of a silicon substrate, with each orifice of the dot pattern mask corresponding to a desired location of a microneedle. Orifices are formed that pass completely through the substrate by etching. A nitride pattern mask is formed to mask all areas in which a nitride layer is not desired. A nitride layer is then deposited on the bottom of the silicon substrate, on the walls of the orifice, and on the top of the silicon substrate around the periphery of the orifice. The nitride layer around the periphery of the orifice is offset somewhat, such that one side of the orifice has a larger nitride layer. Anisotropic etching is used to remove a substantial portion of the substrate, creating a plurality of angular, blunt, and generally pyramidal-shaped microneedles. A subsequent removal of the nitride layer, followed by an isotropic etching step, softens and rounds out the blunt angular microneedles, providing generally conical-shaped microneedles. The uneven nitride layer adjacent the orifice ensures that the microneedles will include a beveled tip. Such microneedle arrays are preferably incorporated into handheld diagnostic and drug delivery systems.
Abstract:
This invention relates to a method for locally depositing coatings on microtip apex. The technical procedures are listed as following. (1) Using parting layer to cover the tip body and only leave the apex protruded A parting layer was deposited on the entire microtip sample surface. The film thickness is thicker than the height of microtip. By thinning the parting layer, the tip apex was exposed, but the body remains being covered. The height of the exposed tip apex can be controlled by adjusting the thinning parameters. (2) Surface cleaning and passivation treatment Surface cleaning and passivation treatment are performed on the apex of the microtip according to actual needs. (3) Coating Based on actual needs, a selected functional thin film is coated on the microtip sample. (4) Remove the parting layer to form the locally coated tip By using an etchant that only react with the parting layer but not the microtip and the coated material, the parting layer can selectively removed, leave a locally coated microtip. Using the aforementioned method, it is able to perform surface cleaning and locally thin film depositing on microtip apex.
Abstract:
A method of providing a microprojection (180) on the surface of a first material, the microprojection having a base portion adjacent the first material and a remote, or a tip portion, and a duct (182) at least in a region of the tip portion and the method comprising micro-machining the first material to provide the micro-projection duct. Various uses of the microprojection are also disclosed including light guides and cuvettes from micro-analytical systems, microneedles for transdermal fluid delivery or the like.
Abstract:
Microneedle arrays are fabricated by providing a sacrificial mold including a substrate and an array of posts, preferably solid posts, projecting therefrom. A first material is coated on the sacrificial mold including on the substrate and on the array of posts. The sacrificial mold is removed to provide an array of hollow tubes projecting from a base. The inner and outer surfaces of the array of hollow tubes are coated with a second material to create the array of microneedles projecting from the base. The sacrificial mold may be fabricated by fabricating a master mold, including an array of channels that extend into the master mold from a face thereof. A third material is molded into the channels and on the face of the master mold, to create the sacrificial mold. The sacrificial mold then is separated from the master mold. Alternatively, wire bonding may be used to wire bond an array of wires to a substrate to create the sacrificial mold. The first material preferably is coated on the sacrificial mold by plating. Prior to plating, a plating base preferably is formed on the sacrificial mold including on the substrate and on the array of posts. The inner and outer surfaces of the array of hollow tubes preferably are coated with the second material by overplating the second material on the inner and outer surfaces of the array of hollow tubes.
Abstract:
The present invention provides a microneedle incorporating a base that is broad relative to a height of the microneedle, to minimize breakage. The microneedle further includes a fluid channel and a beveled non-coring tip. Preferably arrays of such microneedles are fabricated utilizing conventional semiconductor derived micro-scale fabrication techniques. A dot pattern mask is formed on an upper surface of a silicon substrate, with each orifice of the dot pattern mask corresponding to a desired location of a microneedle. Orifices are formed that pass completely through the substrate by etching. A nitride pattern mask is formed to mask all areas in which a nitride layer is not desired. A nitride layer is then deposited on the bottom of the silicon substrate, on the walls of the orifice, and on the top of the silicon substrate around the periphery of the orifice. The nitride layer around the periphery of the orifice is offset somewhat, such that one side of the orifice has a larger nitride layer. Anisotropic etching is used to remove a substantial portion of the substrate, creating a plurality of angular, blunt, and generally pyramidal-shaped microneedles. A subsequent removal of the nitride layer, followed by an isotropic etching step, softens and rounds out the blunt angular microneedles, providing generally conical-shaped microneedles. The uneven nitride layer adjacent the orifice ensures that the microneedles will include a beveled tip. Such microneedle arrays are preferably incorporated into handheld diagnostic and drug delivery systems.
Abstract:
An array of hollow microneedles is constructed of molded plastic, in which a micro-machining technique is used to fabricate the molds used in a plastic microforming process. The molds are detachable and can be re-used. The preferred process for making the plastic arrays of microneedles is a microinjection technique. In the microinjection method, a molten plastic substance is injected between two micro-machined molds that contain microhole and micropillar arrays. Once the desired shape of the microneedle array has been formed, the mold and the plastic material are cooled down. Next, the molds are separated and the plastic microneedle array is detached from the mold structures.
Abstract:
A method for manufacturing microneedle structures is disclosed using soft lithography and photolithography, in which micromold structures made of a photoresist material or PDMS are created. The micromold manufacturing occurs quite quickly, using inexpensive materials and processes. Once the molds are available, using moldable materials such as polymers, microneedle arrays can be molded or embossed in relatively fast procedures. In some cases a sacrificial layer is provided between the forming micromold and its substrate layer, for ease of separation. The microneedles themselves can be solid projections, hollow nullmicrotubes,null or shallow nullmicrocups.null Electrodes can be formed on the microneedle arrays, including individual electrodes per hollow microtube.
Abstract:
A device, preferably a micro-device, is molded from a plastic material by injection molding, compression molding or embossing. A microabrader can be molded having microneedles for abrading the stratum corneum of the skin to form an abraded site in the tissue for enhancing drug delivery. The micro-device is molded using a mold assembly having a silicon molding surface. The silicon molding surface can include a recess corresponding to the desired shape and length of the microneedles. The silicon molding surface enables micron and submicron size features to be molded from polymeric materials without the polymeric material adhering to the mold surface. Micro-devices having molded features having micron and submicron dimensions can be rapidly produced without the use of a release agent.
Abstract:
A first embodiment microneedle array is constructed of silicon and silicon dioxide compounds using MEMS technology and standard microfabrication techniques to create hollow cylindrical individual microneedles. The resulting array of microneedles can penetrate with a small pressure through the stratum corneum of skin to either deliver drugs or to facilitate interstitial fluid sampling through the hollow microneedles into the epidermis. The delivery of drugs and sampling of fluids can be performed by way of passive diffusion (time release), instantaneous injection, or iontophoresis. In a second embodiment, an array of hollow (or solid) microneedles is constructed of plastic or some other type of molded or cast material. An electric field may be used to increase transdermal flow rate, and the microneedles can be effectively combined with the application of an electric field between an anode and cathode attached to the skin which causes a low-level electric current. As a drug delivery system, the microneedle array includes electrodes that apply an electric potential to the skin between the electrode locations. One of the electrode assemblies is filled with an ionized drug, and the charged drug molecules move into the body due to the applied electric potential. As a body-fluid sampling system, the microneedle array also includes electrodes to assist in moving fluid from the body into a receiving chamber, and which further includes a bioelectrochemical sensor to measure the concentration of a particular substance.