mikronåle

Microneedles, or mikronålar, are tiny needles designed for transdermal delivery and sampling. They are typically 25 to 900 micrometers in length, short enough to avoid stimulating nerve endings in the deeper dermis while still breaching the stratum corneum. This enables drug or vaccine delivery through the skin with minimal pain compared to conventional injections.

There are several microneedle designs. Solid microneedles create microchannels when pressed into the skin. Coated microneedles carry a drug coated on their surface, which dissolves after insertion. Hollow microneedles form a channel for liquid delivery. Dissolvable or swellable microneedles are made from polymers or sugars that dissolve or retract in the skin, releasing their payload.

Materials vary: silicon and metals such as stainless steel or titanium; polymers such as PLGA, polyvinylpyrrolidone, carboxymethyl cellulose, or hyaluronic acid; and sometimes sugars. Manufacturing methods include lithography and etching for solid silicon needles, micro-molding, hot embossing, and 3D printing for polymer types.

Applications span medicine and cosmetics. In medicine, microneedles are explored for vaccines, insulin and other peptides, analgesics, and biologics, enabling self-administration and improved stability. In cosmetics, they are used to enhance delivery of anti-aging compounds and other actives and to assist skin microcirculation and collagen production in some devices.

Advantages include reduced pain, avoidance of first-pass metabolism, potential for self-administration, and improved patient adherence. Limitations include small dose capacity, variable skin properties, risk of infection if aseptic technique is not followed, and higher manufacturing costs for certain designs. Regulatory status varies by jurisdiction and product type; some microneedle devices have cleared regulatory pathways for specific indications, while many are still in clinical trials.