Thermoplasmonic-Triggered Release of Loads from DNA-Modified Hydrogel Microcapsules Functionalized with Au Nanoparticles or Au Nanorods

Microcapsules consisting of hydrogel shells cross-linked by glucosamine–boronate ester complexes and duplex nucleic acids, loaded with dyes or drugs and functionalized with Au nanoparticles (Au NPs) or Au nanorods (Au NRs), are developed. Irradiation of Au NPs or Au NRs results in the thermoplasmonic heating of the microcapsules, and the dissociation of the nucleic acid cross-linkers. The separation of duplex nucleic acid cross-linkers leads to low-stiffness hydrogel shells, allowing the release of loads. Switching off the light-induced plasmonic heating results in the regeneration of stiff hydrogel shells protecting the microcapsules, leading to the blockage of release processes. The thermoplasmonic release of tetramethylrhodamine-dextran, Texas Red-dextran, doxorubicin-dextran (DOX-D), or camptothecin-carboxymethylcellulose (CPT-CMC) from the microcapsules is introduced. By loading the microcapsules with two different drugs (DOX-D and CPT-CMC), the light-controlled dose release is demonstrated. Cellular experiments show efficient permeation of Au NPs/DOX-D or Au NRs/DOX-D microcapsules into MDA-MB-231 cancer cells and inefficient uptake by MCF-10A epithelial breast cells. Cytotoxicity experiments reveal selective thermoplasmon-induced cytotoxicity of the microcapsules toward MDA-MB-231 cancer cells as compared to MCF-10A cells. Also, selective cytotoxicity towards MDA-MB-231 cancer cells upon irradiation of the Au NPs- and Au NRs-functionalized microcapsules at λ = 532 or 910 nm is demonstrated.