# Lattice matching enables construction of CaS@NaYF4 heterostructure with synergistically enhanced water resistance and luminescence for antibiotic detection

## TL;DR

A new CaS-based material with improved water resistance and luminescence is developed for detecting antibiotics.

## Contribution

A lattice-matching strategy creates a CaS:Ce3+@NaYF4 heterostructure with enhanced water resistance and luminescence.

## Key findings

- The CaS:Ce3+@NaYF4 heterostructure effectively protects the core from degradation in water.
- The material enables ultrasensitive detection of kanamycin with a detection limit of 7.8 nM.
- The aptasensor successfully detects kanamycin in tap water and milk samples.

## Abstract

Rare earth (RE)-doped CaS phosphors have been widely used as light-emitting components in various fields. Nevertheless, the application of nanosized CaS particles is still significantly limited by their poor water resistance and weak luminescence. Herein, a lattice-matching strategy is developed by growing an inert shell of cubic NaYF4 phase on the CaS luminescent core. Due to their similarity in crystal structure, a uniform core–shell heterostructure (CaS:Ce3+@NaYF4) can be obtained, which effectively protects the CaS:Ce3+ core from degradation in aqueous environment and enhances its luminescence intensity. As a proof of concept, a label-free aptasensor is further constructed by combining core–shell CaS:Ce3+@NaYF4 and Au nanoparticles (AuNPs) for the ultrasensitive detection of kanamycin antibiotics. Based on the efficient FRET process, the detection linear range of kanamycin spans from 100 to 1000 nM with a detection limit of 7.8 nM. Besides, the aptasensor shows excellent selectivity towards kanamycin antibiotics, and has been successfully applied to the detection of kanamycin spiked in tap water and milk samples, demonstrating its high potential for sensing applications.

The online version contains supplementary material available at 10.1007/s00604-024-06568-x.