The cytosolic innate immune sensor cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway is crucial for priming adaptive antitumour immunity through antigen-presenting cells (APCs). Natural agonists such as cyclic dinucleotides (CDNs) activate the cGAS-STING pathway, but their clinical translation is impeded by poor cytosolic entry and serum stability, low specificity, and rapid tissue clearance. Here, we developed an ultrasound (US)-guided cancer immunotherapy platform using nanocomplexes composed of 2’3’ cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) electrostatically bound to biocompatible branched cationic biopolymers that are conjugated onto APC-targeting microbubbles (MBs). The nanocomplex-conjugated MBs engaged with APCs and efficiently delivered cGAMP into the cytosol via sonoporation, resulting in activation of cGAS-STING and downstream proinflammatory pathways that efficiently prime antigen-specific T cells. This bridging of innate and adaptive immunity inhibited tumour growth in both localized and metastatic murine cancer models. Our findings demonstrate that targeted local activation of STING in APCs under spatiotemporally US stimulation results in systemic antitumour immunity and improves the therapeutic efficacy of checkpoint blockade, thus paving the way toward novel image-guided strategies for targeted immunotherapy of cancer.

The success of messenger RNA therapeutics largely depends on the availability of delivery systems that enable the safe, effective and stable translation of genetic material into functional proteins. Here we show that extracellular vesicles (EVs) produced via cellular nanoporation from human dermal fibroblasts, and encapsulating mRNA encoding for extracellular-matrix α1 type-I collagen (COL1A1) induced the formation of collagen-protein grafts and reduced wrinkle formation in the collagen-depleted dermal tissue of mice with photoaged skin. We also show that the intradermal delivery of the mRNA-loaded EVs via a microneedle array led to the prolonged and more uniform synthesis and replacement of collagen in the dermis of the animals. The intradermal delivery of EV-based COL1A1 mRNA may make for an effective protein-replacement therapy for the treatment of photoaged skin.Recent developments in messenger RNA-modification techniques have enhanced the therapeutic efficiency of mRNA delivery and its potential for near-term clinical applications, including protein-replacement therapy and vaccination against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus 1,2 . However, the intrinsic inability and potential immunogenicity of mRNAs require that they be encapsulated within delivery vehicles. Current mRNA-delivery modalities centre on the usage of lipid nanoparticle (LNP) carriers for encapsulation and