Upconversion nanoparticles (UCNPs) represent a group of NPs that can convert near-infrared (NIR) light into ultraviolet and visible light, thus possess deep tissue penetration power with less... Show moreUpconversion nanoparticles (UCNPs) represent a group of NPs that can convert near-infrared (NIR) light into ultraviolet and visible light, thus possess deep tissue penetration power with less background fluorescence noise interference, and do not induce damage to biological tissues. Due to their unique optical properties and possibility for surface modification, UCNPs can be exploited for concomitant antigen delivery into dendritic cells (DCs) and monitoring by molecular imaging. In this study, we focus on the development of a nano-delivery platform targeting DCs for immunotherapy and simultaneous imaging. OVA 254-267 (OVA24) peptide antigen, harboring a CD8 T cell epitope, and Pam3CysSerLys4 (Pam3CSK4) adjuvant were chemically linked to the surface of UCNPs by amide condensation to stimulate DC maturation and antigen presentation. The OVA24-Pam3CSK4-UCNPs were thoroughly characterized and showed a homogeneous morphology and surface electronegativity, which promoted a good dispersion of the NPs. In vitro experiments demonstrated that OVA24-Pam3CSK4-UCNPs induced a strong immune response, including DC maturation, T cell activation, and proliferation, as well as interferon gamma (IFN-gamma) production. In vivo, highly sensitive upconversion luminescence (UCL) imaging of OVA24-Pam3CSK4-UCNPs allowed tracking of UCNPs from the periphery to lymph nodes. In summary, OVA24-Pam3CSK4-UCNPs represent an effective tool for DC-based immunotherapy. Show less
Feng, Y.S.; Chen, H.R.; Wu, Y.N.; Que, I.; Tamburini, F.; Baldazzi, F.; ... ; Zhang, H. 2020
Side effect is one of the main factors affecting the success of cancer therapies in clinic. Patients treated with photodynamic therapy (PDT) suffer mainly from the phototoxicity due to the... Show moreSide effect is one of the main factors affecting the success of cancer therapies in clinic. Patients treated with photodynamic therapy (PDT) suffer mainly from the phototoxicity due to the relatively long time blood circulation of the tumor enrichment and they have also to be protected from background light for days after the treatment. Here we introduce a new design of nanophotosensitizers in which the luminescence upconversion nanoparticles loaded with photosensitizers are self-assembled into a nanoball with the aid of a specific pH-sensitive polymer layer containing overloaded photosensitizers and quenching molecules. This design makes the therapy function "off/on" possible, i.e. only imaging during the circulation of the nanoballs ascribing to the near-infrared (NIR) photon upconversion of the nanoballs and the pH-sensitive shell. Activation of PDT solely occurs once the nanoballs are taken up by the cancer cells due to the acidic microenvironment. This design prevents effectively the photodamage of the photosensitizers during enrichment and targeting process of tumor, as validated in vitro and in vivo, which enables imaging-guided PDT treatment of deep-seated tumor in a much more relax and comfortable way for patients. This patient-friendly nanomaterial construction strategy can also be extended to other therapies. Show less
