Abstract: A simple tissue biosensor for measuring Na+ channel blocks such as tetrodotoxin(TTX) has been developed. The membrane of frog bladder has Na+ channels which control the passage of Na+. It is well known that TTX blocks Na+ channels. The tissue biosensor consists of a Na+ electrode integrated within a TTX solution. The tip of the electrode was covered with frog bladder membrane sandwiched between two sheets of cellulose acetate membrane, and the electrode was set in a TTX solution. The solution of pNa=4 NaCl was injected in the TTX solution and the output of the electrode allowed to stabilize. TTX was injected into the sensor system and measured from the inhibition ratio of the sensor peak output. One assay took approx 5min. The lower limit of detection was 0.0002μg/ml. The continuous detention of TTX was feasible for 250h in the presence of 0.003% NaN3. A linear correlation was obtained between TTX activities in fugu muscles detected by methods of TTX sensor and mouse assay.

Key words:  , fugu； tetrodotoxin； biosensor； detection；