Selective detection of 17β-estradiol in water using an upconversion luminescence–based Förster resonance energy transfer aptasensor

Consistent exposure to 17β-estradiol (E₂) through water and food sources poses considerable health risks, necessitating the development of sensitive E₂ detection methods. Herein, an E₂ nanosensor based on Förster resonance energy transfer (FRET) was developed by immobilizing amino-SiO₂-modified upconversion nanoparticles core–shell structures functionalized with E₂-specific aptamers on graphene oxide (GO) nanosheets. The aptamers adsorbed onto GO via π–π stacking interactions, facilitating the FRET-induced upconversion luminescence (UCL) quenching. Upon E₂ addition, the aptamers detached from GO surface, restoring the UCL intensity. The as-developed nanosensor exhibited a strong linear response to E₂ concentrations in the range of 10–200 ng/mL with a detection limit of 6.39 ng/mL. Furthermore, the high recovery rates (88–98 %) of the sensor validated its reliability. Thus, the fabricated sensor demonstrated excellent potential for the accurate detection of E₂ in aqueous environments.