Development of Local Anesthetic Sensor

1.局部麻醉敏感电极：采用直径0.8mm的铜丝包覆含离子对、二辛酯、四氢呋喃的PVC基质膜制备包覆丝电极。还研制了直径为0.05mm的微电极。参考电极由Ag/AgCl制成，连接生理盐水琼脂桥。灵敏度：这些传感器对浓度范围为10^<-6>至10^<-2> mol/L的局麻药敏感。检测限为10^<-8> mol/L。根据Henderson-Hasselbalch方程，电极对局麻药质子化形式的浓度变化有响应。温度对能氏斜率有影响。选择性：体内无离子影响电极电位。电极的局部麻醉剂越疏水，它受到其他局部麻醉剂分子的干扰就越少。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，电极电位随游离白蛋白分子的减少而变化，因此可以很容易地得到局部麻醉剂在一个白蛋白分子上的结合位点数。5个二布卡因分子与一个白蛋白分子结合。体内实验：根据双室模型分析，家兔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。传感器测得的浓度与HPLC分析结果一致。局麻药代谢物的作用：利多卡因代谢物影响电极电位。MEGX和羟利多卡因的选择性为1*10^<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>.