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In this paper, near-infrared (NIR) light responsive polyelectrolyte multilayer capsules (PE/Au NRs@Dox) were successfully synthesized by layer-by-layer techniques. Gold nanorods with aspect ratio of 3.9, and a longitudinal absorbance peak at 765nm were prepared using seed-mediated method which used the cationic surfactant cetyltrimethylammonium bromide (CTAB) as a soft template and structure-guiding agent. Sequential layers of polyanions (sodium polystyrene sulfonate (PSS)) and polycations (poly diallyldimethylammonium chloride (PDADMAC)) were followed by adsorption of three BSA/PSS bilayers. The doxorubicin (Dox) is loaded by the electrostatic interaction. The release of Dox from the swelling polyelectrolyte complex PE/Au NRs@Dox was induced by the heat generated from gold nanorods under laser irradiation. Moreover, the in vitro cytotoxicity of PE/Au NRs@Dox and the doxorubicin release from the composites were investigated.

Cell adhesion molecule integrin αvβ3 is an excellent target for tumor interventions because of its unique expression on the surface of several types of solid tumor cells and on almost all sprouting tumor vasculatures. In this manuscript, we describe the synthesis of near-infrared (NIR) fluorochrome ICG-Der-02-labeled dimeric cyclic RGD peptides (ICG-Der-02-c(RGDyK)2) for in vivo tumor integrin targeting. The optical properties and structure of the probe were intensively characterized. Afterwards, the integrin specificity of the fluorescent probe was tested in vitro for receptor binding assay and fluorescence microscopy and in vivo for subcutaneous MDA-MB-231 and U87MG tumor targeting. The results indicated that after labeling RGD peptide, the optical properties of ICG-Der-02 showed no obvious change. Besides, in vitro and in vivo tumor targeting experiment indicated that the ICG-Der-02-c(RGDyK)2 probe with high integrin affinity showed excellent tumor activity accumulation. Noninvasive NIR fluorescence imaging is able to detect tumor integrin expression based upon the highly potent RGD peptide probe.