Dual-emitting persistent luminescence-based Ratiometric Aptasensor without complementary-strand and in-situ...

Rapid quantification of bioactive lactoferrin (LF) is crucial for food safety and nutrition. We present a ratiometric aptasensor that couples an LF-specific aptamer with dual-emission ZnGa₂O₄:Cr_0.0001 persistent-luminescence nanoparticles (520 nm and 714 nm) for accurate determination of bioactive LF. Cy dye, used instead of conventional quencher-labeled cDNA, suppresses the 714 nm signal via resonance energy transfer. Upon LF existence, LF competes with the aptamer-Cy interaction, releasing Cy and restoring the 714 nm emission proportionally, while 520 nm signal remains constant for internal calibration. The sensor eliminates hybridization and in-situ excitation, cutting cost and complexity. It offers a 600-1100 ng mL^-1 linear range, 56.24 ng mL^-1 detection limit and excellent selectivity. Bioactive LF in dairy products and nutrition fortifier was quantified with 96.5%-102.3% recoveries, and various thermal-caused inactivation rates were also accurately mapped, validating the sensor for quality-control applications.