Silicon nanoparticles represent a new class of imaging agents with emission lifetimes in the 1 to 100 microsecond range. This important timescale--many cellular transport processes, neuronal transmission events, and biochemical reactions occur on microsecond timescales--offers opportunities for silicon nanoparticle probes to be deployed for such imaging problems. Furthermore, when in contact with cellular conditions, the emission spectrum from silicon nanoparticles evolves on a much longer timescale (minutes to days) based on slow oxidation and dissolution of the nanostructure. This presentation will discuss the photophysical properties that enable time-gated and related imaging modalities, and it will discuss chemical modifications that can be deployed to allow porous Si nanoparticles to traffic between the cellular surface (via peptide targeting) and the cell interior (via membrane fusogenic coatings) to improve fidelity of in vitro and in vivo images.
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