Scheme 1

The synthesis process of EA-CDs and bioimaging experiments."

Fig 1

(a) TEM, HRTEM images and size statistical distribution diagram of EA-CDs in aqueous solution; (b) Raman spectrum (λex = 532 nm), (c) FT-IR transmission spectrum of EA-CDs; (d) Cu Kα XRD pattern, (e) XPS survey spectrum of EA-CDs; High-resolution (f) C 1s, (g) N 1s, and (h) O 1s XPS peaks of EA-CDs."

Fig 2

(a) UV-Vis absorption (red), Photoluminescence Excitation Spectroscopy (PLE) (black), and Photoluminescence Spectroscopy (PL) (blue) spectra of EA-CDs; (b) the fluorescence emission spectra of EA-CDs excited at various wavelengths; Fluorescence variation of the EA-CDs as a function of (c) pH; (d) thermal; (e) irradiation time; and (f) concentration of NaCl."

Fig 3

CLSM images of onion epidermal tissues treated with EA-CDs at different concentrations and incubation times. These vertical panels show optical images of onion epidermal cells at different incubation time (30, 60, and 120 min) under the same EA-CDs concentration; while the horizontal panels show the optical images treated with different concentrations (0, 25, and 50 μg·mL−1) of EA-CDs at the same incubation time. Red channel parameters: λex = 561 nm; λem = 600−800 nm. Scale bar, 100 μm."

Fig 4

CLSM images of onion epidermal tissues treated with 25 μg mL−1 EA-CDs for 240 min. The following picture is an enlarged view of the white area in the above picture. Red channel parameters: λex = 561 nm; λem = 600−800 nm. Scale bar, 100 μm."

Fig 5

Bioimaging of Saccharomyces cerevisiae using EA-CDs (10 μg mL−1). EA-CDs display successful microbial labeling with red fluorescence. Scale bar, 40 μm."

Fig 6

In vivo bioimaging of zebrafish larvae treated with EA-CDs. (a) Zebrafish larvae were incubated with 10 μg mL−1 (left panel) and (b) 100 μg mL−1 (right panel) EA-CDs, followed by Z-stack confocal imaging across multiple focal planes (Z = 1 to Z = 10), Scale bar, 200 μm."