Evaluation of a sol particle immunoassay for pregnancy detection

Assembly and Degradation of Inorganic Nanoparticles in Biological Environments

“…1,4 By modification of the Au NP surface with molecules that upon presence of specific binding partners in solution caused agglutination, i.e., cross-linking of the NPs, colorimetric assays for immunoassays were developed. 5,6 Decades later, the same concept was applied for ultrasensitive colorimetric detection of DNA. 7 In the direction of cellular staining, antibody modified Au NPs have been applied as contrast agents for transmission electron microscopy (TEM) imaging.…”

“…Early examples in this direction were agglutination and cellular staining assays . In the case of agglutination assays, if Au NPs were brought closely together, light-excited surface plasmons could couple, which changed the color of the Au NP suspension. , By modification of the Au NP surface with molecules that upon presence of specific binding partners in solution caused agglutination, i.e., cross-linking of the NPs, colorimetric assays for immunoassays were developed. , Decades later, the same concept was applied for ultrasensitive colorimetric detection of DNA . In the direction of cellular staining, antibody modified Au NPs have been applied as contrast agents for transmission electron microscopy (TEM) imaging .…”

Optical Sensing of Small Ions with Colloidal Nanoparticles

“…61 Quickly, the technique was improved such that the color read-out taken by the naked eye gave correct results with more than 99% confidence. 58,60 Mirkin and co-workers applied the "coupled plasmon resonance technique" to DNA detection, 62 in which plasmonic NPs are modified with oligonucleotides. 62,63 Presence of cDNA in solution links the NPs, and in turn, the LSPR shifts.…”

“…In this way, the presence of ions can be observed in the LSPR spectrum. , Higher specificity can be achieved by using the key–lock interaction of biological receptor–ligand pairs as recognition elements. This effect has been used in immunoassays already in the early 1980s. − Gold nanoparticles were functionalized with two different monoclonal antibodies against human chorionic gonadotropin (HCG, present in the urine of pregnant women). When the Au NPs were dissolved in urine of pregnant women, a color change could be observed in a spectroscopic setup .…”

“…When the Au NPs were dissolved in urine of pregnant women, a color change could be observed in a spectroscopic setup . Quickly, the technique was improved such that the color read-out taken by the naked eye gave correct results with more than 99% confidence. , Mirkin and co-workers applied the “coupled plasmon resonance technique” to DNA detection, in which plasmonic NPs are modified with oligonucleotides. , Presence of cDNA in solution links the NPs, and in turn, the LSPR shifts . The same idea can be used for the detection of ions.…”