Gated Luminescence Imaging of Silicon Nanoparticles.

TitleGated Luminescence Imaging of Silicon Nanoparticles.
Publication TypeJournal Article
Year of Publication2015
AuthorsJoo J, Liu X, Kotamraju VRamana, Ruoslahti E, Nam Y, Sailor MJ
JournalACS Nano
Volume9
Issue6
Pagination6233-41
Date Published2015 Jun 23
ISSN1936-086X
Abstract

The luminescence lifetime of nanocrystalline silicon is typically on the order of microseconds, significantly longer than the nanosecond lifetimes exhibited by fluorescent molecules naturally present in cells and tissues. Time-gated imaging, where the image is acquired at a time after termination of an excitation pulse, allows discrimination of a silicon nanoparticle probe from these endogenous signals. Because of the microsecond time scale for silicon emission, time-gated imaging is relatively simple to implement for this biocompatible and nontoxic probe. Here a time-gated system with ∼10 ns resolution is described, using an intensified CCD camera and pulsed LED or laser excitation sources. The method is demonstrated by tracking the fate of mesoporous silicon nanoparticles containing the tumor-targeting peptide iRGD, administered by retro-orbital injection into live mice. Imaging of such systemically administered nanoparticles in vivo is particularly challenging because of the low concentration of probe in the targeted tissues and relatively high background signals from tissue autofluorescence. Contrast improvements of >100-fold (relative to steady-state imaging) is demonstrated in the targeted tissues.

DOI10.1021/acsnano.5b01594
Alternate JournalACS Nano
PubMed ID26034817