Enhancement of photothermal toxicity and lung targeting delivery of Au nanorods via heparin-based nanogelElectronic supplementary information (ESI) available: Synthesis and characterization of heparin-PEI-LA nanogel and AuNRs-nanogel complexes in vitro, the protocol to prepare AuNRs-nanogel complexes. See DOI: 10.1039/c4ra16012f

In this study, we report a synthesis of a surface modified heparin-based nanogel using d , l -alpha-lipoic acid. Heparin-PEI-LA nanogel could exist stably in aqueous solution with uniform size distribution. Transmission electron microscopy (TEM) observation showed that the developed heparin-PEI-LA nanogel could adsorb gold nanorods to form AuNRs-nanogel complexes with the aid of a reducing agent such as DTT. Then, the photothermal conversion efficiency and photothermal conversion for killing tumor cell in vitro of these nanogel complexes were detected. The improved cellular killing efficiency of AuNRs-nanogel might be due to an increased cellular uptake of gold nanorods in vitro . Moreover, Cy-7-labelled heparin-PEI-LA nanogel could be enriched in the lungs suggesting the potential use of the nanogel system for targeting the delivery of gold nanorods and a great potential application in the tumor photothermal therapy. The scheme of preparation of heparin-PEI-LA nanogel used for the adsorption of Au nanorods.