An ultrasensitive quantum dots fluorescent polarization immunoassay based on the antibody modified Au nanoparticles amplifying for the detection of adenosine triphosphate

Optical Aptasensors for Adenosine Triphosphate

“…Similar to many other fluorescent ATP aptasensors mentioned above, ATP detection is based on fluorescence quenching when ATP binds to the aptamer and releases the intercalated Hoechst33258 into solution 64 . In addition, QDs in conjugation with fluorescence polarization immunoassay (FPIA) were explored for ATP detection 65 . FPIA is based on the principle that the fluorescence polarization value will be higher when the fluorophore has a bigger volume (weight) and slower rotation.…”

“…With this principle in mind, He et al immobilized an aptamer onto CdS QDs. In the presence of ATP, the immobilized aptamer and another aptamer modified with an antigen (mouse anti-digoxin antigen) bind to ATP 65 . The fluorescence signal is amplified when the antibody, anti-digoxin immobilized to gold nanoparticles binds to the entire complex, resulting in the formation of a very big conjugate and hence drastically lowers the rotation of the conjugate thus producing a much higher fluorescence polarization value.…”

Recent progress in nanomaterial-enhanced fluorescence polarization/anisotropy sensors

“…Furthermore, the proposed approach could also be extended to detect other antigen-antibody immune complexes by using the respective antigens and corresponding antibodies. Subsequently, the same group demonstrated another ultrasensitive CdSe/CdS QDsbased FPIA system [78] for adenosine triphosphate (ATP) detection by means of anti-digoxin-Au NPs amplification. As demonstrated in Fig.…”

Panoply of Fluorescence Polarization/Anisotropy Signaling Mechanisms for Functional Nucleic Acid-Based Sensing Platforms

“…Figure a,ii depicts another kind of amplified assay based on the split aptamer. One strand is labeled by a core–shell quantum dot while the other fragment is tethered to a digoxin molecule . Addition of the target is responsible for the formation of the ternary complex, which subsequently binds to gold nanoparticles conjugated to an antidigoxin antibody via the antigen–antibody bridge.…”