Streamlined Synthesis of Dual-Emissive Fluorescent Silicon Quantum Dots (SiQDs) for Cell Imaging

Description:
One of the current challenges for working with nanomaterials in bioapplications is having a biocompatible (non-toxic) tool and producing stable, intense fluorescence for bioimaging. To address these challenges, we have developed a streamlined and one-pot synthetic route, based on the hydrothermal method, for generating silicon-based quantum dots (SiQDs). Part of our unique approach to designing the SiQDs was to incorporate (3-aminopropyl) triethoxysilane (APTES), which is an amphipathic molecule with hydroxyl and amine functional groups available for modification. To reduce the toxicity of APTES, we chose glucose as a reducing agent for the reaction. The resulting SiQDs produced potent, stable, dual-emissive fluorescence emission peaks, one is in the visible range and the other is in the near-infrared (NIR) range. Both peaks could be used as distinct fluorescence signals for bioimaging. The physical and optical properties of the SiQDs were determined under a range of environmental conditions. The morphology, surface composition, and electronic structure of SiQDs were characterized using a high resolution-transmission electronic microscope (HR-TEM), energy dispersive X-ray spectrometer (EDS), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS). The stability of the SiQDs was evaluated under a wide range of pHs. The biocompatibility and imaging potential of the SiQDs were tested in several cell lines. The SiQDs displayed different subcellular localizations in different cell types and during cell division. The results demonstrated that SiQDs is a promising non-toxic labeling tool for a wide variety of cell types, with the added advantage of having dual emission peaks in visible and NIR ranges for bioimaging.

Speaker: Di Sun - University of North Dakota
My name is Di Sun, and I'm a Ph.D. student under the supervision of professor Julia Zhao at the University of North Dakota. My research focuses on developing novel fluorescent-based nanoparticles and their biological applications, including bioimaging, drug delivery, and cancer therapy.