Preliminary Studies On Biosensors For Extracorporeal Continuous Monitoring

Electrochemical biosensor has been widely used in the field of medicine, food and environment. It has the properties of high selectivity, convenient to use, and fast detection speed. It is the most common way to detect glucose and lactate. However, it also has some drawbacks: It is little complicate; it needs drawing a droplet of blood with a finger-prick test; we can only detect one kind of sample with one biosensor.In recent years, people pay much attention to their health, so the portable detection device had been developed rapidly and wearable smart devices are very popular. In this paper glucose biosensor and lactate biosensor were made by modifying with different kind of mediators. The screen printed electrode was modified with glucose oxidase and lactate oxidase to manufacture relevant biosensor as preliminarily research to fabricate extracorporeal continuous biosensor on tattoo base paper or other softness paper.First, 1,1'-dimethylferrocene toluidine blue and tetrathiafulvalene were used as mediator to fabricate glucose biosensor. 1,1'-dimethylferrocene and tetrathiafulvalene biosensor have a wide linear range. Toluidine blue biosensor has a lower oxidize potential so it has a high resistance to interference. 1,1'-dimethylferrocene biosensor has a linear range from 1 to 10.4 mM; the corresponding regression equation of the linear plot respectively is I/?A=1.016c+0.1776, R2=0.992;the sensitivity was thus estimated as 1.016 ?A m M⁽-10;the detection limit is 25.04 ?M?S/N=3?. Toluidine blue biosensor has a linear range from 0 to 6.5 m M; the corresponding regression equation of the linear plot respectively is I/?A =4.736c+1.457, R=0.99; the sensitivity was thus estimated as 4.736 ?A mM⁽-10; the detection limit is 19.5 ?M?S/N=3?. Tetrathiafulvalene biosensor has a linear range from 0 to 17.2 mM; the corresponding regression equation of the linear plot respectively is I/?A=3.6780c-7.1078, R2=0.998; the sensitivity was thus estimated as 3.678 ?A mM⁽-10; the detection limit is 25.19 ?M?S/N=3?.Second, tetrathiafulvalene toluidine blue and prussian blue were used as mediator to fabricate lactate biosensor. Tetrathiafulvalene and toluidine blue biosensors detect the oxidation current while prussian blue biosensor detects the reduction current. However, they have similar linear range. Tetrathiafulvalene biosensor has a linear range from 0 to 7.8 mM; the corresponding regression equation of the linear plot respectively is I/?A=7.158c+6.042,R=0.992; The sensitivity was thus estimated as 7.158?A mM⁽-10; the detection limit is 34.76 ?M?S/N=3?. Toluidine blue biosensor has a linear range from 1 to 7 mM; the corresponding regression equation of the linear plot respectively is I/?A=6.9485c+1.1362,R=0.990; The sensitivity was thus estimated as 6.9485 ?A mM⁽-10; the detection limit is 13.00 ?M?S/N=3?. Prussian blue biosensor has a linear range from 0 to 7.5 mM; the corresponding regression equation of the linear plot respectively is I/?A=-0.341c-0.252,R2=0.993; the sensitivity was thus estimated as 0.3418 ?A m M⁽-10;the detection limit is 0.62 m M?S/N=3?.Third, glucose electrochemical biosensor and lactate electrochemical biosensor were made on screen printed electrode. It is the preliminarily research of non-invasion continuous monitoring biosensor. The glucose electrochemical biosensor has a linear range from 0 to 12.6 mM; the corresponding regression equation of the linear plot respectively is I/?A =4.218c+2.749,R2=0.99; the sensitivity was thus estimated as 4.218 ?A m M⁽-10;the detection limit is 31.99 ?M?S/N=3?. The lactate electrochemical biosensor has a linear range from 0 to 6 mM; the corresponding regression equation of the linear plot respectively is I/?A=9.768c+1.492, R2=0.99; the sensitivity was thus estimated as 9.768 ?A m M⁽-10; the limit of detection is 83.70 ?M?S/N=3?.