Dumbbell-like upconversion nanoparticles synthesized by controlled epitaxial growth for light-heat-color tri-modal sensing of carcinoembryonic antigen.

Accurate quantitative analysis of tumor markers in a wide linear range has important practical significance towards complex clinical samples in cancer identification and monitoring of tumor development stages, but remains challenging. Herein, three-layer dumbbell-like upconversion nanoparticles NaErF:Tm@NaYF@NaNdF (labeled as UCNPs) combined with G-quadruplex (G) DNAzyme are reported for tri-modal sensing of carcinoembryonic antigen (CEA) in a wide range using upconversion luminescence (UCL), photothermal and catalysis signal readouts. Initially, dumbbell-like UCNPs were controlled synthesized by a three-dimensional epitaxial growth strategy through tuning the concentration of Nd precursors. After surface functionalization, Gzyme-UCNPs-cDNA/Apt-MB was subsequently fabricated by biotin-streptavidin interaction and DNA hybridization. Quantitative detection of CEA was achieved by competitive interaction and magnetic separation, and the intensities of tri-modal signals (light, heat and catalysis-based chrominance) of dissociative probes are linearly related to the concentration of CEA. The results showed that the tri-modal sensing method exhibited a wide linear range (0.005-2000 ng/mL) and low limit of detection (LOD) across three models: the luminescence model (0.005-50 ng/mL, LOD = 0.910 pg/mL), the catalysis model (10-1000 ng/mL, LOD = 0.387 ng/mL), and the temperature model (50-2000 ng/mL, LOD = 1.114 ng/mL). These findings suggest that the tri-modal sensing platform is suitable for use in the analysis of a wide range of complex and diverse clinical samples.