DENDRIMER-GOLD NANOPARTICLE HYBRIDS FOR BIOMEDICAL APPLICATIONS

摘要

We attempted to produce a new type of functional nanomaterials using combination of dendrimers and gold nanoparticles (GNPs) for biomedical applications We loaded gold nanoparticles into the interior of thermosensitive oligoethylene glycol-modified PAMAM dendrimers by reducing AuCl_4 ions with NaBH_4 in the dendrimer interior. We found that the GNP-loaded dendrimers exhibited aggregation and dissolution responding to the ambient temperature below and above the cloud point. The dendrimers with hydrophobic surface associates strongly with the cells above the LCST and kills efficiently by photo-induced heat generation. We also prepared hybrid dendrimers consisting of a gold nanorod (GNR) core and PEG-modified PAMAM (PEG-PAMAM) dendrons by adding PEG-PAMAM G3 dendrimers with cystamine core at various timings during the GNR growing reaction. The GNR-core PEG-PAMAM G3 dendrimer exhibited excellent heat-generation capability under near-infrared light irradiation. The GNR-core PEG-PAMAM G3 dendrimer injected into mice tumor tissues significantly increased the temperature of the tumor when irradiated with near infrared light, resulting in decreased tumor volume. In addition, we prepared GNR hybridized with PEG-modified PAMAM dendrimers having doxorubicin (DOX). We found that these PEG-dendrimer-DOX-GNR hybrids were able to kill tumor cells through the synergy of DOX-derived chemo-effect and GNR-derived photothermal effect under near infrared irradiation. These dendrimer-GNP hybrids might be useful as a new type of nanomaterial for biomedical applications such as drug delivery and nanomedicine.