Development of Local Anesthetic Sensor

1.局麻药敏感电极：用含有离子对、邻苯二甲酸二辛酯和四氢呋喃的PVC膜包裹直径为0.8mm的铜丝制成涂丝电极。2.灵敏度：传感器对浓度范围为10 μ mol/L ~ 10 μ mol/L的局麻药具有灵敏度<-6>，<-2>检测限为10 μ mol/L<-8>，电极对质子化局麻药浓度的变化符合Henderson-Hasselbalch方程。温度影响能斯特斜率。3.选择性：体内无离子影响电极电位。电极的局麻药疏水性越强，受其他局麻药分子的干扰就越小。4.与白蛋白的相互作用：白蛋白本身不影响电极的基线电位。由于与白蛋白结合后，电极电位随游离麻醉剂分子的减少而变化，因此很容易得到一个白蛋白分子上局麻药的结合位点数。5.体内研究：根据二室模型分析，兔体内V_1=0.111/kg，V_2=0.121/kg，<12>k_1 =1.88/min，k_2 =0.88/min，<21>k_3 <10>=1.88/min。6.局部麻醉药代谢产物的影响：利多卡因代谢产物影响电极电位。MEGX和羟基利多卡因的选择性均为1 × 10 ~ 4<0.6-0.8>。

1.Local anesthetic-sensitive electrodes : The coated-wire electrodes wereprepared by coating copper wires (0.8mm in diameter) with membranes of PVC matrix included the ion pairs, dioctylphtalate, and tetrahydrofuran. A microelectrodes (0.05mm in diameter) were also developed.The reference electrode was made of Ag/AgCl connecting a normal saline agar bridge.2.Sensitivity : These sensors were sonsitive to local anesthetics of concentration range 10^<-6> to 10^<-2> mol/L.The detecting limitation was 10^<-8> mol/L.The electrodes rsponded to the concentrationchanges of protonated form of local anesthetics according to the Henderson-Hasselbalch equation. Temperature influenced the Nernstian-slopes.3.Selectivity : No ions in the body affected the electrode potentials. The more hydrophobic the electrode's localanesthetic, the less it is interfered with by other local anesthetic molecules.4.Interaction with albumin : Albumin itself did not affect the baseline potential of the electrode. As the electrode potential changed with the decreasein free anesthetic molecules after binding with albumin, it's easy to get the number of binding sites for local anesthetics on one albumin molecule. Five dibucaine molecules binds on one albumin molecule.5.In vivo study : According to the two compartment model analysis, V_1=0.111/kg, V_2=0.121/kg, k_<12>=1.88/min, k_<21>=0.88/min, k_<10>=1.88/min in rabbit study. The concentrations from our sensor agreed with those from HPLC analysis.6.Effects of metabolites of local anesthetics : The metabolites of lidocaine influenced the electrode potentials. The selectivities of MEGX and hydroxylidocaine were 1*10^<0.6-0.8>.