Microfabricated Microneedles for Gene and Drug Delivery

Abstract

By incorporating techniques adapted from the microelectronics industry, the field of microfabrication has allowed the creation of microneedles, which have the potential to improve existing biological-laboratory and medical devices and to enable novel devices for gene and drug delivery. Dense arrays of microneedles have been used to deliver DNA into cells. Many cells are treated at once, which is much more efficient than current microinjection techniques. Microneedles have also been used to deliver drugs into local regions of tissue. Microfabricated neural probes have delivered drugs into neural tissue while simultaneously stimulating and recording neuronal activity, and microneedles have been inserted into arterial vessel walls to deliver anti-restenosis drugs. Finally, microhypodermic needles and microneedles for transdermal drug delivery have been developed to reduce needle insertion pain and tissue trauma and to provide controlled delivery across the skin. These needles have been shown to be robust enough to penetrate skin and dramatically increase skin permeability to macromolecules.

Microfabricated needles for transdermal delivery of macromolecules and nanoparticles: Fabrication methods and transport studies

“…2 offer a number of practical advantages. First, fabrication of metal and polymer microneedles should be less expensive and readily scalable to mass production because: (i) metal and polymer raw materials are widely available and generally less expensive than silicon wafers, (ii) the electroplating and polymer molding techniques used to make these needles can be set up in a conventional manufacturing environment without the need for cleanroom facilities, and (iii) the fabrication techniques we developed involve relatively simple single-step molding operations, which contrasts with most other published methods that require more complex multistep fabrication schemes (24).…”

Approaches and Challenges of Engineering Implantable Microelectromechanical Systems (MEMS) Drug Delivery Systems for in Vitro and in Vivo Applications

“…As suggested by Praunitz et al [26], mirconeedles will increase the skin permeability to a wide range of molecules and nanoparticle formulations. There are a broad range of microneedles which include silicon microprobes, glass microcapillaries, and silicon/polysilicon microhypodermic needles that can be used for cellular, local and systemic delivery [27]. These microneedles are integrated into either reservoir type or matrix type patches, which can then be applied onto the skin for transdermal drug delivery.…”

Enabling topical immunization via microporation: a novel method for pain-free and needle-free delivery of adenovirus-based vaccines

“…Other devices that are being developed to deliver vaccines to the epidermis include, ballistic particle delivery ('gene gun'), microprojections, electroporation and liquid jet injectors. [7][8][9][10] There are no clear criteria at this point to identify the optimal device for epidermal delivery, however, the flexibility, reproducibility, and ease of use of the microporation technology makes it highly attractive for this application.…”