Bilayered near-infrared fluorescent nanoparticles based on low molecular weight PEI for tumor-targeted in vivo imaging
To improve the tumor fluorescent imaging results in vivo, bilayered nanoparticles encapsulating a lipophilic near-infrared (NIR) fluorescent dye 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindotri-carbocyanine iodide (DiR) were prepared using low molecular weight stearic acid-grafted polyethyleneimine and hyaluronic acid (DiR-PgSHA nanoparticles), which were investigated as a novel NIR fluorescent nano-probe for in vivo tumor-targeted optical imaging. These nanoparticles were characterized by transmission electron microscopy (TEM), infrared (IR) spectra, UV-visual absorption, and fluorescent emission spectra. Their cytotoxicity in vitro and hepatotoxicity in vivo were tested by MTT assay and histological study, respectively. In vivo NIR fluorescence imaging of the DiR-PgSHA nanoparticles was performed using a Carestream imaging system. The DiR-PgSHA nanoparticles were sphere shaped with a diameter of approximately 50 nm according to the TEM images. The DiR-PgSHA nanoparticles had a low cytotoxicity in vitro according to the MTT assay and low hepatotoxicity in vivo as determined in histological studies. The fluorescent emission of DiR-PgSHA nanoparticles was stable in pH values of 5–9 in solution, with only slight blue-shifts of the emission maxima at the basic pH range. The DiR-PgSHA nanoparticles exhibited a substantial tumor-targeting ability in the optical imaging with the use of tumor-bearing mice. These results demonstrated that the DiR-PgSHA nanoparticle is an excellent biocompatible nano-probe for in vivo tumor-targeted NIR fluorescence imaging with a potential for clinical applications.
KeywordsNear-infrared Fluorescence Nanoparticle Tumor-targeting In vivo imaging
This study was supported by National Basic Research Program 973 of China (No. 2010CB732603 and No. 2011CB707903), the National Nature Science Foundation of China (Nos. 81271686 and 81228011), the grants of Shaanxi province science and technology and innovation project (Nos. 2011KTCL03-07), US National Institutes of Health Grant (R01 CA121830 S1), K-INBRE (P20 GM103418), and Kansas Bioscience Authority Rising Star Award (to L. X.).
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