434910 Layer-By-Layer Nanoparticles for Delivery of Second Window Near-Infrared Probes in Vivo

Thursday, November 12, 2015: 10:10 AM
253A (Salt Palace Convention Center)
Li Gu1, Xiangnan Dang2, Jifa Qi3, Angela M. Belcher2 and Paula T. Hammond4, (1)Koch Institute for Integrative Cancer Research, MIT, Cambridge, MA, (2)Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, (3)Material Science and Engineering, MIT, Cambridge, MA, (4)Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA

Second window near-infrared (NIR-II) imaging provides fluorescence-based anatomical information deep to skin as NIR-II light (1000 nm to 1700 nm) features deep tissue penetration, reduced tissue scattering, and negligible tissue autofluorescence. NIR-II fluorescence imaging probes; including down-conversion particles, quantum dots, single-walled nanotubes, and organic dyes, are formulated in biocompatible layer-by-layer (LbL) nanoparticles. 150 - 200 nm size range is obtained and hyaluronic acid is used as outer layer for extended blood circulation. Systemic delivery of LbL nanoparticles in Balb/c mice demonstrates that down-conversion particles have least autofluorescence due to its relative longer emission wavelength (>1500 nm). Organic dyes with emission at 1100 nm show most autofluorescence and elevated tissue scattering. Both quantums dots and single-walled nanotubes give moderate autofluorescence and tissue scattering. Pharmacokinetics studies of the LbL probes indicate that layer-by-layer formulation extends the blood circulation with half-life from 14 ~ 23 hrs. Tissue histology suggests none of the LbL probes present major toxicity. A further imaging involving orthotopic ovarian tumor is conducted using down-conversion particles due to its relative low autofluorescence. At 96 hrs, tumor is visualized in deep intraparatoneal cavity with high resolution. In this work, we present a first example of head-to-head comparison of all current NIR-II probes using LbL formulation. In vivo imaging performance is evaluated and suggests NIR-II imaging is versatile and robust technique for biomedical applications.

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