Masking nanoparticle surfaces for sensitive and selective colorimetric detection of proteins.
We have developed a convenient and efficient colorimetric detection system for protein targets using aptamer-gold nanoparticle conjugates. We take advantage of the correlation between the catalytic properties and the exposed surface area of the nanoparticles, which is inversely proportional to the amount of the aptamer-bound protein targets. As the concentration of the protein target increases, the nanoparticle surface area becomes more masked, thus increasing the reduction time of 4-nitrophenol for the color change. We also reduce the detection time by either redesigning the aptamer sequences or regulating their density. This detection system is highly selective, discriminating the target protein even at a concentration 1000 times higher than the limit of detection (LOD). Importantly, to the best of our knowledge, the LOD with the unaided eye in this work is the lowest for a colorimetric detection system using lysozyme as a model protein (16 nM). Lysozyme in chicken egg whites is directly analyzed using our detection system, whose results are in excellent agreement with the enzyme-linked immunosorbent assay (ELISA) analysis.
Department of Materials Science and Engineering, Korea University , Seoul 136-713, Republic of Korea.
Byung-Ho
BH
Kim
In Seon
IS
Yoon
Jae-Seung
JS
Lee
D001483:Base Sequence; D003124:Colorimetry / Q000379:methods*; D017931:DNA Primers; D006046:Gold / Q000737:chemistry; D057230:Limit of Detection; D053768:Metal Nanoparticles; D011506:Proteins / Q000032:analysis*; D013499:Surface Properties
D017931:DNA Primers; D011506:Proteins; D006046:Gold