ped as a noninvasive alternative to injections, though low absorption through the skin has limited these patches to select compounds such as nicotine and steroids. Enter the microneedles - micron sized needles capable of delivering drugs beneath the skin with the absorptive powers of injections and without their painful pricks.One might ask, why must we deliver nanometer sized drugs through millimeter sized needles? There is no reason for this size disparity in most cases, and microneedles hold the promise of drug injection at a fine level that bypasses our nerves and saves us from the dreaded prick feeling. Feats in microengineering have finally led to reliant manufacturing of these microneedles to the point where several labs across the country have been able to test these needles in animal models fot the delivery of traditional injection medications like insulin.
The most common method through which these microneedles have been used is through a patch attached to the needle array. Once the patch is placed over the body, the needes can penetrate the shallow layers of skin and commense the injection of drugs. The actual injection can be controlled in a number of ways, from simple diffusion to iontophoresis to polymer control. In iontophoresis, an electrical gradient causes the drug molecules to move in a desired direction. This can be controlled through electric systems on the patch for time control of drug release. Polymers are complex proteins used in drug delivery systems that can act to release drugs due to a timing mechanism or action from external cues.
Today, microneedles can be microfabricated into many designs from many materials including silicon and metal. Studies have shown that patches covered with these needles cause no pain and are, in fact, indistinguishable from normal patches by human subjects. The needles have already been proven successful in animal models and may someday help provide much preferable solutions to injection for medications like insulin.
(FIGURE from mems.gatech.edu)
The most common method through which these microneedles have been used is through a patch attached to the needle array. Once the patch is placed over the body, the needes can penetrate the shallow layers of skin and commense the injection of drugs. The actual injection can be controlled in a number of ways, from simple diffusion to iontophoresis to polymer control. In iontophoresis, an electrical gradient causes the drug molecules to move in a desired direction. This can be controlled through electric systems on the patch for time control of drug release. Polymers are complex proteins used in drug delivery systems that can act to release drugs due to a timing mechanism or action from external cues.
Today, microneedles can be microfabricated into many designs from many materials including silicon and metal. Studies have shown that patches covered with these needles cause no pain and are, in fact, indistinguishable from normal patches by human subjects. The needles have already been proven successful in animal models and may someday help provide much preferable solutions to injection for medications like insulin.
(FIGURE from mems.gatech.edu)
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