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Ch77-I044963.fm Page 381 Tuesday, August 1, 2006 9:45 PM
Page 381
Tuesday, August
1, 2006
9:45 PM
Ch77-I044963.fm
381
381
FABRICATION OF A MICRO NEEDLE MADE OF
BIODEGRADABLE POLYMER MATERIAL
T. Aoki, H. Izumi and S. Aoyagi

Kansai University
3-3-35, Yamate-cho, Suita, Osaka 564-8680, Japan

ABSTRACT
The aim of this paper is the development of a micro needle made of biodegradable polymer (Poly
Lactic Acid, called as PLA). This device is applicable to a blood test system for diabetics. The needle
having the size of 1000 j^m length, 64 ^m height and 127 j^m width has been developed.
Biodegradable polymer naturally degrades itself in tissues; therefore this material is safe for human
body and environment. To achieve the purpose of this study, we have focused on the establishment of
wet chemical etching process and micro-molding processes for PLA. The resistively of PLA against
common chemical etching solutions and dry etching gases is also investigated.

KEYWORDS

Micro needle, PLA(Poly Lactic Acid), Wet chemical etching, Micro-molding, Chemical resistively

INTRODUCTION
Recently, the number of diabetics is increasing in advanced countries, especially in Japan, according to
the change of life-style and the increase of aged people. It is reported by some reference that the ratio
of diabetics (including the suspect of it) is about 10% in Japan. To make matters worse, the generation
of diabetics is becoming younger. They have to collect their blood for the glucose level measurement
at least twice a day, which is indispensable for health monitoring. In this blood collection, they feel
pain and fear when needle is pricked. A commercial needle is usually straight and made of metal at
present state. The new type needle decreasing pain and fear is strongly desired now. On the contrary, a
human being has almost no pain and no fear when he is bitten by a mosquito. The diameter of
mosquito's needle is about 30 um, which is small enough to circumvent the pain spots of a human skin.
And also, mosquito's needle has a jagged shape and it can easily cut out skins with vibration. A jagged
shaped needle has a merit of decreasing the contact area between the surface of the needle and the
dermis of a skin during insertion [1]. Therefore it is considered that the needle can be easily inserted
into a skin with vibration. Several micro needles have been reported for biomedical applications, such
as drug delivery [2], measurement of cortical biopotentials, etc. However, it is difficult to form a
three-dimensional jagged needle shape by micromachining technique. The aim of
this paper is to develop such shaped micro needle made of biodegradable polymer, which is assumed