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Research Paper | Biology | India | Volume 3 Issue 11, November 2014

Design of Aptamer-Gold Nanoparticles Based Colorimetric Assay for the Early Diagnosis of Breast Tumor

Nandita P. Agnihotri | Mangla Bhide

Abstract: Combinatorial chemistry techniques based on the SELEX methodology were used for the identification of the specific aptamers. We have developed a highly specific colorimetric assay for breast tumor antigen (CA 15-3) that uses aptamer-gold nanoparticles (Apt-GNPs) conjugate, to combine the selectivity and affinity of aptamers and the spectroscopic advantages of gold nanoparticles to allow for the sensitive detection of CA 15-3. We have synthesized an Apt-GNPs conjugate that is specific to CA 15-3 and we used this conjugate system to detect CA 15-3 by monitoring the changes in the color and UV-vis extinction spectra of the Apt-GNPs that occur due to the aggregation of Goldnanoparticles. In this colorimetric assay we found, at very low concentration of CA 15-3 i. e.30 units the red color of Apt-GNPs conjugate turned purple and at higher concentration of CA 15-3 i. e. >500 units there were very less extent of aggregation, which is not visible as a change in color. We have checked the change in flocculation intensity in the presence of different concentration of CA 15-3 by UV-vis extinction spectra. The results obtained in this assay would be much helpful in the practical applications of Apt-GNPs conjugate and breast tumor diagnosis.

Keywords: Aptamer, Goldnanoparticle, Breast Tumor, colorimetric assay, CA 15-3

Edition: Volume 3 Issue 11, November 2014,

Pages: 1703 - 1707