One-step synthesis of fluorescent silicon quantum dots (Si-QDs) and their application for cell imaging

Novel fluorescent silicon quantum dots (Si-QDs) were synthesized by a one-step hydrothermal procedure using (3-aminopropyl) trimethoxysilane (APTES) as a silicon source and sodium ascorbate (SA) as a reducing agent. This synthetic strategy is straightforward, efficacious and low-cost. The as-synthesized Si-QDs featured narrow size distribution, intense purple-blue fluorescence with a photoluminescence quantum yield (PL QY) of 21%, complete water solubility, and favorable biocompatibility. Moreover, the resultant Si-QDs present robust stability in different circumstances, such as for long-term storage in air, in a wide pH range of 2-12 and under continuous UV irradiation, and they also do not respond to some metal ions. Their superior stability and safety render Si-QDs applicable as fluorescent probes in biomedical applications. The use of Si-QDs as an optical probe is illustrated by fluorescent imaging of IE8 cells.