Water-soluble silicon nanocrystals as NIR luminescent probes for time-gated biomedical imaging. Issue 14 (31st March 2020)

• Record Type: Journal Article
• Authors: Romano, Francesco; Angeloni, Sara; Morselli, Giacomo; Mazzaro, Raffaello; Morandi, Vittorio; Shell, Jennifer R.; Cao, Xu; Pogue, Brian W.; Ceroni, Paola
• Is Part Of: Nanoscale. Volume 12:Issue 14(2020)
• Page Start: 7921
• Page End: 7926
• Publication Date: 2020-03-31
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/d0nr00814a
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : In vivo studies demonstrated tumor accumulation of luminescent SiNCs, 48 hours clearance and a 3-fold improvement of signal-to-noise ratio in time-gated imaging compared to steady-state acquisition, demonstrating their potentiality for luminescence guided surgery. Abstract : Luminescent probes based on silicon nanocrystals (SiNCs) have many advantages for bioimaging compared to more conventional quantum dots: abundancy of silicon combined with its biocompatibility; tunability of the emission color of SiNCs in the red and NIR spectral region to gain deeper tissue penetration; long emission lifetimes of SiNCs (hundreds of μs) enabling time-gated acquisitions to avoid background noise caused by tissue autofluorescence and scattered excitation light. Here we report a new three-step synthesis, based on a low temperature thiol–ene click reaction that can afford SiNCs, colloidally stable in water, with preserved bright red and NIR photoluminescence (band maxima at 735 and 945 nm for nanocrystals with diameters of 4 and 5 nm, respectively) and long emission lifetimes. Their luminescence is insensitive to dioxygen and sensitive to pH changes in the physiological range, enabling pH sensing. In vivo studies demonstrated tumor accumulation, 48 hours clearance and a 3-fold improvement of the signal-to-noise ratio compared to steady-state imaging.