Microneedles Formed Vertically Within A Semiconductor Substrate

University of California System: University of California, Berkeley
posted on 05/28/2009

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Traditionally, needles for biomedical applications have been fabricated from stainless steel. Recently techniques have been developed for forming needles from semiconductor materials, usually in the horizontal plane of a semiconductor substrate. Researchers at the University of California, Berkeley have developed an improved needle fabrication method, whereby needles are formed vertically in a semiconductor substrate.

Using standard microfabrication techniques, needles may be formed with various vertical slopes and the needle tips may be formed in a variety of shapes. For example, a combination of isotropic and anisotropic etching is used to produce needles with steep vertical walls, while istropic etching alone is used to produce needles wth sloping vertical walls that terminate in wide bases to withstand relatively large lateral forces. Needles of various lengths and diameters may be formed; representative dimensions are 200 microns in length and 25 microns in diameter.

Regents’ patent rights in the vertically-formed needles includes the method of forming the needles and the needles formed thereby.

Transdermal drug delivery
Injection or extraction of gases, fluids or suspensions
Needle arrays may be used to pattern a structure
Interface with instrumentation

Needles may be formed with various slopes and tip shapes for specific applications
Needle arrays may be fabricated
Produces low cost and highly reproducible structures