PURPOSE: To detect and measure a vital material such as urea with high sensitivity by providing aluminum to an FET gate part and immobilizing the vital material to the aluminum surface.
CONSTITUTION: The anodized aluminum 15 is formed to a gate part of 20μm gate length and 1mm gate width of the ISFET structure which is provided with a source region 12 and a drain region 13 on a P-type silicon substrate 10 and has an SiO2 film 14 of 1,000 thickness obtd. by thermal oxidation for 30min at 950W1,000°C on the surface. An immobilized enzyme film 16 is further provided to about 20μm thickness on the ISFET surface to which the anodized aluminum is provided as the gate. The formation of said enzyme film 16 is executed by activating ISFET by 10% γ-APTES and coating a soln. which is prepd. by adding 10μl aq. 50% glutaraldehyde soln. to a soln. mixture composed of urease and bovine serum albumin thereon and effecting reaction for a whole day and night at 4°C. The urea sensor is thus obtd.
YAGISHITA AKIO
YANO EI
SUGAMA AKIO
NAKANE NAOMI
