A New Biomaterial for Vaccination: an Aqueous ZIF-8 Crystal Growth to Preserve Antigens and Enhance the Immune Activation

Biomaterials encompass a broad range of applications for medical treatment and can be on the macroscale, such as heart valves or hip implants, to the microscale and nanoscale, such as stitches, dental fillings or particles for drug delivery. For the last thirty years, biomaterials with sustained release properties have been investigated as a method to improve the delivery of vaccines. Vaccines are considered one of the most significant inventions in the human history, as it has prevented hundreds of millions of deaths since its invention and is the main cause for extending the human life expectancy. However, a major issue with current methods of vaccination is their low stability at room temperature and the requirement for multiple injections to produce an immune response strong enough to develop long-term memory. For these reasons, the “cold chain” infrastructure keeps them refrigerated from manufacturer to clinic, ensuring the epitopes in the proteinaceous vaccines do not unfold. Any failures in this process can lead to the loss of billions of dollars and, even with this system, the proteinaceous material will denature over time. On top of that, the necessity of multiple injections to provide immunity it is clear how heavily we rely on the cold chain. To solve these issues, biomaterials with sustained release properties has been employed to “cage” proteins within a stabilizing polymer network that prevents conformational changes and enables storage at room temperature. Herein, methods to encapsulate proteinaceous material under aqueous conditions within zeolitic imidazole framework-8 (ZIF-8), a well-studied metal organic framework, is investigated for it’s ability to activate the immune system in mice and protect vaccines from denaturation.