QF-Pro uses FLIM-FRET to measure protein-protein interactions at 1-10nm resolution directly in tissue. The only platform that turns colocalization into confirmed molecular engagement.
FLIM-FRET provides ground-truth confirmation of protein proximity at 1-10nm—turning colocalization from a statistical inference into a physical measurement.
Multiplex imaging platforms such as CODEX, PhenoCycler, Vectra, MIBI, and IMC generate rich spatial data—but pixel-level colocalization does not prove molecular interaction. Two proteins can share a pixel yet be 200nm apart. QF-Pro resolves this ambiguity by measuring energy transfer that only occurs when molecules are within nanometers of each other.
Diffraction-limited imaging shows overlap; QF-Pro confirms whether colocalized signals represent genuine protein-protein interaction at the molecular scale. Convert probability into certainty.
Add a FRET-based validation layer to any multiplex panel. Confirm that marker co-expression translates to functional engagement—an independent measurement that strengthens publication-quality data.
Unlike binary colocalization calls, FLIM-FRET provides continuous FRET efficiency values proportional to interaction strength—enabling dose-response, threshold, and correlation analyses.
Colocalization analysis tells you two markers occupy the same region. QF-Pro tells you they are physically interacting. This distinction matters for spatial biology researchers validating interaction hypotheses, multiplex platform developers benchmarking colocalization accuracy, antibody manufacturers confirming functional binding in tissue, and pharmaceutical teams building companion diagnostics that require interaction-level evidence.
Current companion diagnostics measure protein presence, not function. A protein can be highly expressed but inactive, or low-expressed but highly engaged.
Immunohistochemistry (IHC) measures how much protein is present, but cannot determine if proteins are actually interacting.
FLIM-FRET technology measures actual protein-protein interactions at molecular scale.
In a retrospective study of 135 NSCLC patients treated with immune checkpoint inhibitors, QF-Pro measurement of PD-1/PD-L1 interaction fundamentally outperformed expression-based biomarkers.
Meanwhile, PD-L1 expression (TPS ≥50%) showed no significant correlation with survival (P=0.162). The functional biomarker identified 24% of patients who would have been excluded by expression-only criteria.
Source: Journal of Clinical Oncology, 2023. Sanchez-Magraner et al.
n=135 NSCLC patients treated with anti-PD-1/PD-L1 therapy.
The QF-Pro platform is backed by extensive peer-reviewed research demonstrating clinical utility across multiple cancer types and biomarker targets.
135 patients. High interaction: 31 months OS. Low interaction: 10 months OS. P<0.0001.
2025"Double high" (both CTLA-4/CD80 + PD-1/PD-L1): 35 months median OS. Neither predicted chemo response.
2022First CTLA-4/CD80 measurement at 1-10nm resolution. Checkpoint interaction did NOT correlate with ligand expression.
2020Established two-site cell-cell amplified FRET method for PD-1/PD-L1 in melanoma and NSCLC.
2017Activation: HR=0.228, P=0.002. Expression: HR=1.390, P=0.548. Function predicts; expression does not.
2022Comprehensive review of PKC, Akt/PKB, HER2-HER3, PD-1/PD-L1 applications in precision medicine.
A 42-minute guided tour of FLIM-FRET functional proteomics — from the physics of energy transfer to clinical validation in 135 NSCLC patients. Interactive chapter guide with 40 topics linked directly to the glossary.
QF-Pro combines precision optics, time-resolved detection, and advanced algorithms to measure molecular interactions directly in tissue.
Measures fluorescence lifetime changes caused by energy transfer between interacting proteins.
Learn about FLIM →FRET only occurs when proteins are within nanometers of each other—confirming direct molecular interaction.
Learn about FRET Efficiency →Dual-antibody coincidence detection provides inherent specificity for true protein-protein interactions.
Learn about iFRET →Structured journeys through key topics, with narrative context that explains why each concept matters and how they connect.
The physics of FLIM-FRET: from fluorescence lifetime to clinical measurement.
5 conceptsWhy measuring function beats measuring expression—the paradigm shift.
5 conceptsThe molecular brakes of immunity and how immunotherapy releases them.
5 conceptsSignaling molecules that drive cancer—and why activation state matters.
5 conceptsFrom patient tissue to molecular measurement—the practical workflow.
3 conceptsWhere science meets patient care—diseases, outcomes, and impact.
5 conceptsA comprehensive reference covering FLIM-FRET technology, spatial proteomics, and their applications in cancer research. Built to support understanding of functional biomarkers.
A distance-dependent quantum mechanical process where energy transfers non-radiatively from an excited donor fluorophore to an acceptor fluorophore. FRET efficiency is inversely proportional to the sixth power of the distance between molecules, making it exquisitely sensitive to molecular proximity at the 1-10nm scale.
Explore the technology behind functional biomarkers and see how QF-Pro is transforming precision oncology.
