The matched chromophore pair that enables FRET detection–engineered for optimal spectral overlap and clinical tissue compatibility.
Effective FRET requires significant spectral overlap between donor emission and acceptor excitation. Too little overlap yields weak energy transfer; too much creates spectral bleed-through artifacts.
The ATTO488/Alexa594 pair used in QF-ProLoading... was selected for: (1) large Forster radiusLoading... (5.83 nm), (2) minimal direct acceptor excitation, (3) compatibility with FFPE tissue autofluorescence, and (4) stable lifetime properties for FLIMLoading... detection.
The Matching Problem: For FRET to work, the donor must emit light that the acceptor can absorb. Their spectra must "overlap" appropriately.
Simple Analogy: Like a radio transmitter and receiver—they must be tuned to compatible frequencies to communicate.
In iFRETLoading... and aFRETLoading..., donor and acceptor chromophores are conjugated to primary antibodies targeting each protein of interest. When PD-1 and PD-L1 are interacting, the antibody-bound chromophores come close enough for FRET.
TSALoading... can boost signal-to-noise by depositing multiple chromophores at each antibody binding site, enabling detection in challenging tissue contexts while preserving the proximity requirement.
How Labels Are Attached: QF-Pro uses species-specific secondary antibodies carrying the donor or acceptor. This allows flexibility in choosing primary antibodies while maintaining consistent FRET pair chemistry.
Advantage: Researchers can use their preferred primary antibodies; the secondary antibodies provide the optimized FRET pair.
