Inventory of advantages of time-resolved fluorescent microspheres
Time resolved fluorescent microspheres, as a special functional microsphere, are polystyrene microspheres with rare earth ion complexes embedded inside. The rare earth ions embedded inside are generallyEu3+Tb3+Sm3+And Dy3+It is associated with certain ligands such as β- After the formation of complexes with ketones and aromatic amines, they can absorb ultraviolet light and emit strong lightRare earth ion characteristic fluorescence.
The advantages of time-resolved fluorescent microspheres also stem from their internal embedding process and the characteristics of fluorescent dyes (rare earth ion complexes).
>>>Internal embedding process<<<
Time resolved fluorescent microspheres are embedded with fluorescent dyes inside, which can effectively prevent the leakage of fluorescent dyes and ensure optimal surface activity when coupled with biomolecules.
Each microsphere is embedded with countless fluorescent molecules, effectively improving the fluorescence intensity and analytical sensitivity.
>>>Rare earth ion complexes<<<
Due to the low luminescence efficiency of rare earth ions, they form complexes with ligands with high absorption coefficients. The ligands absorb the laser and transition to the excited state, transferring energy to the rare earth ions. When the rare earth ions receive the transferred energy, they are excited to the resonance level and emit fluorescence during the transition back to the ground state, exhibiting strong rare earth ion characteristic fluorescence.
▲ Luminescence mechanism of rare earth ion complexes
(S0 is the ground state of the ligand, S1 is the lowest excited singlet state of the ligand, T1 is the excited state of the ligand, and En is the excited state of rare earth ions)
Based on the above microsphere structure and luminescence mechanism, time-resolved fluorescent microspheres have the following characteristics compared to ordinary fluorescent microspheres:
Internal embedding process
--Dye free surface for easy coupling
• •fluorescence intensity
--Compared to ordinary red or green fluorescent microspheres, the fluorescence intensity is higher
• •stokes shift
--Larger than ordinary fluorescent microspheres (mostly above 250nm)
• •half life
--Long fluorescence lifetime and strong anti-interference ability
The time-resolved fluorescence lifetime is usually around 100 μ The fluorescence lifetime of rare earth complexes is several orders of magnitude higher than that of ordinary fluorescent microspheres, due to the fact that the luminescence of rare earth complexes is caused by the energy transfer of ligand excited states
• •stability
--The stability of rare earth ion complexes is higher than that of ordinary fluorescence, and the inter batch differences are more stable
At present, the most common time-resolved fluorescent microspheres contain rare earth element europium (Eu) embedded inside,POCT is mainly used in personal health management, clinical applications, infectious disease and major epidemic detection, on-site law enforcement testing (such as alcohol testing, drug testing, forensic toxicology testing), and food safety testingThe development of fluorescent quantitative immunochromatographic test strip products, combined with fluorescence quantitative detectors, can achieve rapid quantitative detection of different indicators.
