Synthesis of broad-spectrum tunable photoluminescent organosilicon nanodots from lac dye for cell imaging

Abstract

To further develop the fluorescence detecting application of lac dye, a novel organosilicon nanodots LSiNDs was synthesized via a simple one-step hydrothermal reaction between lac dye and organic silane. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy demonstrated that the LSiNDs are rich in abundant oxygen-containing functional groups (silicon-oxygen, hydroxyl, and amide groups) and have a polyaromatic structure. The LSiNDs demonstrated a broad-spectrum tunable photoluminescent performance with a narrow size distribution (2.6 ± 0.9 nm). They can emit blue, green, orange, and red fluorescence from 420 nm to 900 nm by varying the excitation wavelengths. In particular, it can emit fluorescence between 770 nm and 900 nm in the near infrared region, which has the advantages of strong tissue penetration and little autofluorescence interference. In addition to their excellent stability and biocompatibility, LSiNDs have a fluorescence quantum yield of up to 49% at 350 nm excitation. Finally, the LSiNDs have been effectively applied as a sensitive fluorescent probe for HepG2 live cell imaging. So, this work expands on how lac dye can be used in fluorescence imaging and other fields of biology.