Hepatitis B virus detection increased using gold nanoparticle immunosensor

(Nanowerk News) Researchers from University of Tehran succeeded in designing and production of an immunosensor based on nanotechnology to increase the rate and accuracy of the detection of hepatitis B virus existing in patients’ blood serum.
In this research ("Gold nanoparticle based capacitive immunosensor for detection of hepatitis B surface antigen"), gold nanoparticles were used to increase the sensitivity of the immunosensor. The sensor is able to detect at least 10 ng/mL of hepatitis B surface antigen. Results of the research can be used in the production of immunosensors with high quality for the detection of various types of viruses, and the sensors can be used in diagnosis tests in hospitals.
The immunosensor was produced in three phases. At first, the second type antigen was connected to gold nanoparticles. Then, gold nanoparticles were coated by an insulating molecule layer (mercapto alkyl ended to carboxylic acid) through self-arrangement method. Afterwards, carboxylic acid functional groups were chemically activated to connect the antigen to the nanoparticles. The antigen connected to gold nanoparticles and stabilized on the initial antigen formed complex on gold electrodes, and changed the capacity of the capacitor.
Gold nanoparticles were used in this research to increase the sensitivity of the immunosensor, and the secondary antigen was stabilized on the surface of gold nanoparticles. Due to the large size of the nanoparticles, the secondary antigen connected to gold nanoparticles creates noticeable changes in dielectric layer and the capacity of the capacitor. In addition to increasing the sensitivity, it decreases the detection limit to about 10 ng/mL.
Source: INIC