Aptamer-Modified Gold Nanoparticles for Colorimetric Determination of Platelet-Derived Growth Factors and Their Receptors

Abstract

We have developed a highly specific sensing system for platelet-derived growth factors (PDGFs) and platelet-derived growth factor receptors (PDGFR) that uses gold nanoparticles (GNPs). We synthesized GNPs modified with an aptamer (Apt-GNPs) that is specific to PDGFs and used them to detect PDGFs by monitoring the changes in the color and extinction of the Apt-GNPs that occur as a result of aggregation. The color of the Apt-GNPs changes from red to purple at low concentrations (<400 nM), but changes only slightly at higher concentrations (>400 nM). We found that the sensitivity of the Apt-GNPs for the three PDGFs is highly salt-dependent, with an optimum condition of 200 mM NaCl. We obtained biphasic curves when plotting of the ratios of the extinction coefficients of the Apt-GNPs at 650 and 530 nm against the concentrations of PDGF-AA at various concentrations of Apt-GNPs. The linear ranges of the increases and decreases in this extinction ratio are 2.5-10 and 10-20 nM, respectively, for 0.42 nM Apt-GNPs and 25-75 and 75-200 nM, respectively, for 8.4 nM Apt-GNPs. When using 8.4 nM Apt-GNPs, the corresponding linear ranges of the increases and decreases in this extinction ratio are 15-100 and 100-400 nM, respectively, for PDGF-AB and 35-150 and 150-400 nM, respectively, for PDGF-BB. In addition, we have developed a homogeneous assay to detect the PDGF receptor-beta (PDGFR-beta) at concentrations as low as 3.2 nM, on the basis of the competition between the Apt-GNPs and PDGFR-beta for PDGF-BB. The results we present in this paper imply that there are practical applications of Apt-GNPs in protein analysis and cancer diagnosis.

Peptide antisense nanoparticles

“…For example, DNA-Au NPs have been used for the detection of nucleic acids (10)(11)(12)(13)(14)(15), small molecules (16,17), metal ions (18), ultrasensitive detection of proteins (19)(20)(21)(22)(23)(24), and intracellular mRNA (25). In addition, these materials have been used in the synthesis of crystalline materials with predefined structures (26,27).…”

Aptasensors for biosecurity applications

“…[39] In the presence of platelet-derived growth factor (PDGF) protein targets, the aptamer-AuNP system begins to aggregate. Subsequently, changes to both the color and extinction of the AuNP, due to changes in aggregation states, can be monitored in real time (Fig.…”

Cancer cell sensing and therapy using affinity tag-conjugated gold nanorods

“…The colour of the nanoparticles also changes depending on the absorption maxima variations. This tuneability of the optical absorption facilitates various biomedical applications including, but not limited to, colorimetric detection assays for proteins [15][16][17][18], DNAs [18][19][20][21] and cancer cells [22] that operate in the visible range; photothermal therapy [23][24][25][26][27][28], photoacoustic imaging (PAI) [29][30][31][32][33][34] and heat-induced drug delivery [35] that operate in the NIR range.…”