Fabrication of Double Emission Enhancement Fluorescent Nanoparticles with Combined PET and AIEE Effects

• Published in: Molecules (Basel, Switzerland) Switzerland), 2020-12, Vol.25 (23), p.5732
• Main Authors: Wu, Hsing-Ju, Chang, Cheng-Chung
• Format: Article
• Language: English
• Subjects: A549 Cells; Aggregates; aggregation-induced emission enhancement (AIEE); Biomarkers; Biomarkers - metabolism; Cell Line, Tumor; Core-shell particles; Coupling agents; Dengue fever; Diagnostic Imaging - methods; double emission enhancement (DEE); Drug carriers; Drug Carriers - chemistry; Drug delivery; Dyes; Electron transfer; Emissions; Fabrication; Fluorescence; Fluorescent Dyes - chemistry; fluorescent silica nanoparticles (FSN); HeLa Cells; Humans; Image Enhancement - methods; Nanomaterials; Nanoparticles; Nanoparticles - chemistry; Naphthalimides - chemistry; Optical properties; photoinduced intramolecular electron transfer (PET); Quantum dots; Reagents; Silica; Silicon Dioxide - chemistry; Solvents; Solvents - chemistry; Spectrometry, Fluorescence - methods; Stöber method
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules25235732

The major challenge in the fabrication of fluorescent silica nanoparticles (FSNs) based on dye-doped silica nanoparticles (DDSNs) is aggregation-caused fluorescence quenching. Here, we constructed an FSN based on a double emission enhancement (DEE) platform. A thio-reactive fluorescence turn-on molecule, -butyl-4-(4-maleimidostyryl)-1,8-naphthalimide (CS), was bound to a silane coupling agent, (3-mercaptopropyl)-trimethoxysilane (MPTMS), and the product -butyl-4-(3-(trimethoxysilyl-propylthio)styryl)-1,8-naphthalimide (CSP) was further used to fabricate a core-shell nanoparticle through the Stöber method. We concluded that the turn-on emission by CSP originated from the photoinduced electron transfer (PET) between the maleimide moiety and the CSP core scaffold, and the second emission enhancement was attributed to the aggregation-induced emission enhancement (AIEE) in CSP when encapsulated inside a core-shell nanoparticle. Thus, FSNs could be obtained through DEE based on a combination of PET and AIEE effects. Systematic investigations verified that the resulting FSNs showed the traditional solvent-independent and photostable optical properties. The results implied that the novel FSNs are suitable as biomarkers in living cells and function as fluorescent visualizing agents for intracellular imaging and drug carriers.