1

Urea Assay KitBy: Sajad Rafatiyan

2

Content• Importance of urea• Urease• Applications• Biosensor• Companies• Carriers• Immobilization methods• Mechanism• References

3

Urea

• Normal concentration at blood 3.6-8.9 mol/L• Urea is primarily produced in the liver and secreted by the kidneys.

Urea is the major end product of protein catabolism in animals. It is the primary vehicle for removal of toxic ammonia from the body.• Urea determination is very useful for the medical clinician to assess

kidney function of patients.

4

• Increased urea levels are associated with nephritis, renal ischemia, urinary tract obstruction, and certain extrarenal diseases, e.g., congestive heart failure, liver diseases and diabetes.

• Decreased levels indicate acute hepatic insufficiency or may result from over-vigorous parenteral fluid therapy.

5

Urease

• E.C. 3.5.1.5• Optimum pH = 7.4• Optimum Temperature = 60° C • Nickel dependent• Need Mg and Co in in-vitro

6

7

Microbial Biochemical Test

8

9

Biosensor• it consist of a biocatalyst which is connected to a transducer, this

transducer can convert a biological signal to an electrical signal and measure it.

• Have different parts:• Biocatalyst• Transducer• Amplifier• Signal processor

10

11

12

Application of biosensor• Medical diagnoses• Environmental analysis• Food quality determination• Drug-Chemical industry• etc…

13

Urea biosensor• Narang and et. Al made a new protocol for entrapping urease in soil

gel film in 1994.They use cilica sol -gel electrode for measuring urea with Potentiometric method. It is more thermostable than free urease.

• Lee and et. Al designed conductometric biosensor for serum's urea basis on immobilized urease on sol-gel electrode IDA in 2000. it can detected urea in low dilution.IDA is a good conductometric. This biosensor show really good stability (63% on 25 days).

14

• Narang and collaborators made a new protocol for entrapping urease in soil gel film in 1994.They use cilica sol -gel electrode for measuring urea with Potentiometric method. It is more thermostable than free urease.

• Lee and collaborators designed conductometric biosensor for serum's urea basis on immobilized urease on sol-gel electrode IDA in 2000. it can detected urea in low dilution.IDA is a good conductometric. This biosensor show really good stability (63% on 25 days).

15

Companies• Sigma

• Abnova

• Ceymen chemical

16

carriers• Polyacrylamide• Nylon• DEAE• Sepharose• Cellulose• Celica

17

Immobilization• Adsorption

• Cross-link

• Entrapment (sol-gel)

18

19

20

21

22

Standard Curve in 96-well plate assay

23

24

Refrences• Anthony P.F. Turner, B. D. (2003). Advannces in biosensors:

Perspectives in biosensors (Vol. v.5). Elsevier.• Zawada, R. J. (2009). Quantitive determination of urea concentrations

in cell culture medium. Biochem, 87, 541-544.• www.sigmaaldrich.co• www.abnova.com/promotions• www.caymanchem.com• www.cellbiolabs.com

25

Thank you for you attention