Detection of gold nanoparticles using an immunoglobulin-coated piezoelectric sensor

Since the existence of nanoparticles in our environment has already attracted considerable attention due to their possible toxic impact on biological systems, the field detection of nanoparticles is becoming a technology that will be much in need. We have constructed a piezoelectric sensor with an antibody-coated electrode. The antiserum can bind gold nanoparticles with a high degree of selectivity and sensitivity. The biosensor thus constructed can detect 4, 5, or 6 nm gold nanoparticles (GNPs) depending on the coated antiserum. The sensitivity for the detection of 5 nm GNPs was 10.3 +/- 0.9 ng Hz(-1), with the low limit of detection at 5.5 ng. A quartz crystal microbalance (QCM) sensor was capable of detecting GNPs and other types of nanoparticle, such as ZnO, or Fe3O4. The current study provides, for the first time, a platform for detecting nanoparticles in a convenient, economical manner.