Plastic and nonmetallic article shaping or treating: processes – Mechanical shaping or molding to form or reform shaped article – Shaping against forming surface
Reexamination Certificate
1999-09-29
2001-12-18
Tentoni, Leo B. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Mechanical shaping or molding to form or reform shaped article
Shaping against forming surface
C264S320000, C264S322000, C264S328100, C264S337000, C264S338000
Reexamination Certificate
active
06331266
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method of manufacturing a device, and particularly, a micro-device. More particularly, the invention is directed to a method of molding a micro-device for medical use.
BACKGROUND OF THE INVENTION
There has been an increase in interest in processes for the manufacture of small devices in the field of biological and biochemical analysis. The manufacture of devices used for analytical testing uses techniques similar to those used in the electronics industry. Examples of these manufacturing techniques include photolithography and wet chemical etching. The devices are often made from solid substrates such as silicon and glass.
Microanalytical devices have been used for performing various analytical reactions. For example, U.S. Pat. No. 5,498,392 to Wilding et al. discloses a mesoscale device having microfabricated fluid channels and chambers in a solid substrate for the performance of nucleic acid amplification reactions. U.S. Pat. No. 5,304,487 to Wilding et al. discloses a mesoscale device having a cell handling region for detecting an analyte in a sample. The microchannels and chambers have a cross-sectional dimension ranging from 0.1 micron to 500 microns. U.S. Pat. No. 5,885,470 to Parce et al. discloses a microfluidic transport device made from a polymeric substrate having fluid channels that can be a few microns wide.
The prior processes for microfabrication of polymeric substrates typically involve stamp molding or embossing. These processes often require the use of a release agent or coating on the molding surface.
There has also been an increased interest in microneedle injection for the transdermal delivery of various drugs. The microneedle devices can have a plurality of microneedles with a length of a few hundred microns. These devices are usually made from silicon or other metals using etching methods. Although effective, the resulting microneedle devices are expensive to manufacture and are difficult to produce in large numbers. One example of a microneedle device for delivering a drug to a patient is disclosed in U.S. Pat. No. 5,879,326 to Godshall et al.
Microneedle drug delivery devices are able to penetrate the stratum corneum of the skin with less irritation. The stratum corneum is a complex structure of compacted keratinized cell remnants having a thickness of about 10-30 microns and forms a waterproof membrane to protect the body from invasion by various substances and the outward migration of various compounds. The delivery of drugs through the skin is enhanced by either increasing the permeability of the skin or increasing the force or energy used to direct the drugs through the skin.
One method of delivering drugs through the skin is by forming micropores or cuts through the stratum corneum. By penetrating the stratum corneum and delivering the drug to the skin in or below the stratum corneum, many drugs can be effectively administered. The devices for penetrating the stratum corneum generally include a plurality of micron size needles or blades having a length to penetrate the stratum corneum without passing completely through the epidermis. Examples of these devices are disclosed in U.S. Pat. No. 5,879,326 to Godshall et al.; U.S. Pat. No. 5,250,023 to Lee et al.; and WO 97/48440.
The prior methods and apparatus for the manufacture of micro-devices for medical use has exhibited some success but is generally time consuming and expensive. Accordingly, a continuing need exists in the industry for an improved method for the manufacture of micro-devices.
SUMMARY OF THE INVENTION
The present invention is directed to a method of manufacturing devices, such as, micro-devices for medical and other uses. The method and apparatus of the invention are suitable for molding plastic devices having micron and submicron features. The medical micro-devices are devices having channels, needles, points or other structural features having dimensions ranging from less than 1 micron to several hundred microns in length or width. Examples of micro-devices that can be molded in accordance with the present invention include analytical microchannel devices, microneedles, pipettes and the like. Analytical microchannel devices, for example, can include microchannels having a diameter ranging from about 0.5 microns to about 500 microns.
In one embodiment of the invention, the micro-device is used for penetrating or abrading the stratum corneum of the skin and for the transdermal delivery of a substance, such as a drug or pharmaceutical agent, through the abraded area. The device includes a plurality of microneedles for abrading and preparing a delivery site on the skin to enhance the delivery of a substance through the stratum corneum of the skin to a sufficient depth where the substance can be absorbed and utilized by the body.
Accordingly, a primary object of the invention is to provide a method for efficiently manufacturing a micro-device from plastic or other materials.
Another object of the invention is to provide a method of molding a micro-device from a polymeric material using a mold capable of molding submicron-size features which can be readily removed from the mold surface.
A further object of the invention is to provide a method of molding a micro-device from a polymeric material in a cost-efficient manner.
A further object of the invention is to provide a cost efficient method of manufacturing a device having microneedles of several microns in length.
Another object of the invention is to provide a method of molding a device having a plurality of microneedles having a length of about 5 to 250 microns.
A further object of the invention is to provide a method of manufacturing by injection molding a device having a plurality of microneedles with a needle density of about 4 to about 100 needles per mm
2
.
A still further object of the invention is to provide a method of molding a micro-device having micron or submicron molded details without the use of a release agent on the mold surface.
Another object of the invention is to provide a mold assembly having a silicon molding surface for injection molding, compression molding or embossing to form a device having a plurality of molded micron or submicron features that can be easily removed from the mold without a release agent.
Still another object of the invention is to provide a method of molding a micro-device using a mold assembly having a mold cavity and silicon molding member attached to the mold assembly within the mold cavity.
The objects of the invention are further achieved by providing a method of molding a device having micron or submicron size features in a mold without the use of a release agent. The mold includes a mold member made of silicon or other material with suitable release properties and having a contoured surface defining an impression of the desired device for molding the micron or submicron size features from a polymeric material. The silicon mold member has a reverse image for molding the features where the molding surface can have recesses or peaks ranging from about 0.5 micron to several hundred microns in length.
The objects of the invention are substantially achieved by providing a method of making a device comprising providing a mold section with a recess defining a mold cavity where the mold cavity has a bottom wall and a silicon mold member disposed therein. The silicon mold member has a contoured surface facing the mold cavity. A hot polymeric material is introduced into the mold cavity to fill the mold cavity and the recesses in the silicon mold member to form a molded device. The mold assembly is then cooled and the molded device is removed from the mold cavity.
The objects, advantages and other salient features of the invention will become apparent from the following detailed description which, taken in conjunction with the annexed drawings, discloses preferred embodiments of the invention.
REFERENCES:
patent: 4614630 (1986-09-01), Pluim, Jr.
patent: 5250023 (1993-10-01), Lee et al.
patent: 5304487 (1994-04-01), Wilding
patent: 54
Monahan Larry A.
Powell Kenneth G.
Sage, Jr. Burton H.
Becton Dickinson and Company
Tentoni Leo B.
Wark, Esq. Allen W.
LandOfFree
Process of making a molded device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process of making a molded device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process of making a molded device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2590357