Enhanced Stability and Controlled Delivery of MOF-Encapsulated Vaccines and Their Immunogenic Response In Vivo.

Vaccines have an innate tendency to lose their structural conformation upon environmental and chemical stressors. A loss in conformation reduces the therapeutic ability to prevent the spread of a pathogen. Herein, we report an in-depth study of zeolitic imidazolate framework-8 and its ability to provide protection for a model viral vector against denaturing conditions. The immunoassay and spectroscopy analysis together demonstrate enhanced thermal and chemical stability to the conformational structure of the encapsulated viral nanoparticle. The long-term biological activity of this virus-ZIF composite was investigated in animal models to further elucidate the integrity of the encapsulated virus, the biosafety, and immunogenicity of the overall composite. Additionally, histological analysis found no observable tissue damage in the skin or vital organs in mice, following multiple subcutaneous administrations. This study shows that ZIF-based protein composites are strong candidates for improved preservation of proteinaceous drugs, are biocompatible, and are capable of controlling the release and adsorption of drugs in vivo.

Regulating the Uptake of Viral Nanoparticles in Macrophage and Cancer Cells via a pH Switch.

Controlling the uptake of nanomaterials into phagocytes is a challenging problem. We describe an approach to inhibit the cellular uptake by macrophages and HeLa cells of nanoparticles derived from bacteriophage Qß by conjugating negatively charged terminal hexanoic acid moieties onto its surface. Additionally, we show hydrazone linkers can be installed between the surface of Qß and the terminal hexanoic acid moieties, resulting in a pH-responsive conjugate that, in acidic conditions, can release the terminal hexanoic acid moiety and allow for the uptake of the Qß nanoparticle. The installation of the "pH switch" did not change the structure-function properties of the hexanoic acid moiety and the uptake of the Qß conjugates by macrophages.