An Amperomertic Uric Acid Biosensor Based on Immobilization of Uricase onto Polyaniline-multiwalled Carbon Nanotube Composite Film

Figures & data

Figure 1. Chemical reaction involved in immobilization of uricase on to PANI/MWCNT Composites.

Figure 2. (2a) Scanning electron micrograhs of PANI deposited on ITO coated glass plate (2b) Scanning electron micrograhs of MWCNT/PANI deposited on ITO coated glass plate (2c) Scanning electron micrograhs of MWCNT/PANI/uricase deposited on ITO coated glass plate.

Scheme 1. Schematic diagram of the uric acid biosensor.

Figure 3. Scheme of electron flow and current generation in uric acid biosensor employing Uricase/MWCNT/PANI/ITO electrode.

Table 1. Effect of various serum substances on response of Uricase biosensor employing Bacillus and Vigna uricase/MWCNT/PANI/ITO electrode

Compound added	Final concentration (Physiological conc.) g/L	*% Relative response uricase/MWCNT/PANI bound electrode
None	–	100
Glucose	0.90	78.6
Pyruvate	0.01	81.6
Cholesterol	2.00	75.0
Urea	0.10	89.0
EDTA	2mmoles	92.0
AscorbicAcid	3.4mmol/l	93.3
Bilirubin	>0.44mg	72.9

Standard assay conditions were used, except for the addition of above compounds individually in the reaction mixture at their physiological concentrations.

*Indicates the value mentioned below is mean value of experiment performed in triplicate.

Figure 4. Calibilration curve for uric acid biosensor with uricase/MWCNT/PANI/ITO electrode.

Figure 5. Correlation between serum uric acid values of diseased individuals determined by standard colorimetric method employing free enzyme (x-axis) and the present by biosensor employing Bacillus uricase/MWCNT/PANI/ITO electrode method (y-axis) (n=60), regression equation being y = 0.969x − 0.046.

Table 2. A comparison of present uric acid biosensor with earlier reported amperometric biosensors

Sr.No	Matrix	Immobilization method	Response time (Sec)	Detection limit (mM)	Linearity (mM)	Interference of ascorbic acid	Stability (days)	Reference
1.	Polyaniline	Electrochemical entrapment	10	–	0.005–1.0	No	60	[31]
2.	Ir-modified carbon electrode	Screen printing	24.7–40.8	0.01	0.1–0.8	Insignificant	10	[32]
3.	MWCNT with SnO2 nanoparticle on GCE	Adsorption	–	–	0.001–0.5	No	20
4.	Polypyrrole	Crosslinking	330	0.005	0.005–1.0	Yes	35	[27]
6.	ZnO nanorodes	Crosslinking	–	0.002	0.005–1	No	20	[14]
8.	Polyaniline	Crosslinking	60	0.01	0.01–0.7	No	126	[15]
9.	Polypyrrole & polyaniline	Electrochemical entrapment	70	–	0.002–0.08	–	28	[10]
10.	Bacillus uricase/PANI/MWCNT/ITO electrode(present electrode)	Covalent	8	0.005	0.005–0.6	No	90	Present

Figure 6. Effect of storage at 4°C on the response of biosensor employing uricase/MWCNT/PANI/ITO electrode.

Kan J., Pan X., Chen C. (2004). Biosens Bioelectron 19(12): 1635.

 PubMed Web of Science ®Google Scholar

Luo Y.C., Do J.S., Liu C. (2006). Biosens Bioelectron 22(4): 482.

 PubMed Web of Science ®Google Scholar

Cete S., Yasar A., Arslan F. (2006). Artif Cells Blood Substit Immobil Biotechnol 34(3): 367.

 PubMedGoogle Scholar

Zhang F., Wang X., Shiyun A.I., Sun Z., Wan Q., Zlu Z., Xian Y., Jin L. (2004). Anal Chim Acta 519(2): 155.

 Web of Science ®Google Scholar

Arora K., Sumana G., Saxena V., Gupta R.K., Gupta S.K., Yakhmi J.V., Pandey M.K., Chand S., Malhotra B.D. (2007). Anal Chim Acta 594(1): 17–23.

 PubMed Web of Science ®Google Scholar

Arslan F. (2008). Sensors, 8: 5492.

 PubMed Web of Science ®Google Scholar