Research Information System
LANGMUIR, vol.38, no.17, pp.5188-5196, 2022 (SCI-Expanded)
We report carboxy-terminated silicon quantum dots(SiQDs) that exhibit high solubility in water due to the high molecularcoverage of surface monolayers, bright light emission with highphotoluminescence quantum yields (PLQYs), long-term stability inthe PL property for monitoring cells, less toxicity to the cells, and a highphotothermal response. We prepared water-soluble SiQDs by thethermal hydrosilylation of 10-undecenoic acid on their hydrogen-terminated surfaces, provided by the thermal disproportionation oftriethoxysilane hydrolyzed at pH 3 and subsequent hydrofluoric etching.The 10-undecanoic acid-functionalized SiQDs (UA:SiQDs) showedlong-term stability in hydrophilic solvents including ethanol and water(pH 7). We assess their interaction with live cells by means of cellularuptake, short-term toxicity, and, for thefirst time, long-term cytotoxicity.Results show that UA:SiQDs are potential candidates for theranostics,with their good optical properties enabling imaging for more than 18 days and a photothermal response having a 25.1%photothermal conversion efficiency together with the direct evidence of cell death by laser irradiation. UA:SiQDs have lowcytotoxicity with full viability of up to 400 mu g/mL for the short term and a 50% cell viability value after 14 days of incubation at a 50 mu g/mL concentration