Fluorescence imaging is a very powerful tool to identify abnormalities in tissues, though it is limited by two factors: (1) the strong absorption and scattering of visible wavelengths of light by mammalian tissues; and (2) the native fluorescence that often overwhelms signals from the probe fluorophore.  This presentation discusses two features of luminescent silicon nanoparticles that can be used to improve the fidelity and resolution of in vivo and in vitro imaging: two-photon excitation and time-gated imaging of the long-lived excited state of quantum-confined silicon. Time-gated imaging is enabled by the long-lived (microseconds) excited state of silicon, allowing suppression of the nanosecond-scale interference from tissue autofluorescence. Furthermore, the dyes commonly used as NIR or two-photon imaging agents often have limited stability and they can display various toxic side effects. By contrast, silicon shows substantially greater photo-stability under one- or two-photon imaging conditions and it displays remarkably low toxicity. This presentation will discuss the use of photoluminescent porous Si nanoparticles as imaging agents, and it will also describe how various molecular targeting groups can improve fidelity of in vivo images

Porous silicon nanoparticles as luminescent probes

256th National Meeting (2018)

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