TEM images of (a and b) Alen-CDs, (c) Alen-EDA-CDs, and (d) FT-IR spectra of alendronate, Alen-CDs, and Alen-EDA-CDs.

(a) XPS spectra for N_1s and (b) ³¹P-NMR spectra.

(a) UV-vis spectra of alendronate, Alen-CDs, and Alen-EDA-CDs; (b) fluorescence spectrum of Alen-CDs; and (c) fluorescence intensities of Alen-CDs and Alen-EDA-CDs

Confocal microscopy images (60×, ex; 405 nm/em; 440–470 nm) of HeLa cells treated with 300 μg mL⁻¹ Alen-CDs and Alen-EDA-CDs: (a) control group, (b) Alen-CDs, and (c) Alen-EDA-CDs.

Fluorescence images of CDHA scaffolds treated with Alen-CDs (300 μg mL⁻¹) and Alen-EDA-CDs (300 μg mL⁻¹) at 37 °C for 12 h.

Fluorescence images of rat femurs treated with Alen-CDs (300 μg mL⁻¹) and Alen-EDA-CDs (300 μg mL⁻¹) at 37 °C for 12 h.

Confocal microscopy images for 6 dpf head skeleton of zebrafish larvae treated with (a and a′) Alen-CDs, (b and b′) Alen-EDA-CDs, and (c and c′) Alizarin Red S. Abbreviations of bones: hyomandibula (hm), opercle (op), ceratobranchial 5 (cb5), cleithrum (cl), entopterygoid (en), branchiostegal ray1 (br1), branchiostegal ray2 (br2). Scale bar = 100 μm.

Confocal microscopy images of zebrafish larvae with (a and a′) Alen-CDs, (b and b′) Alen-EDA-CDs, and (c and c′) Alizarin Red S at 7 dpi. Abbreviations of bones: hyomandibula (hm), opercle (op), cleithrum (cl), entopterygoid (en), branchiostegal ray1 (br1), branchiostegal ray2 (br2).

Schematic illustration of fluorescence imaging via specific affinity for CDHA scaffolds (in vitro), rat femur (ex vivo), and live zebrafish (in vivo) of Alen-CDs.

Schematic illustration of the synthesis and bone affinity of Alen-CDs and Alen-EDA-CDs.