Improving the Thermal Stability of Bacteriophages Through the Novel Use of Ensilication®

Ensilication is a sol-gel method whereby silanol groups are electrostatically bound to positively charged amino acid groups on the surface of the target biomolecule. The end result is the formation of a rigid silica shell around the target preventing it from physically unfolding due to temperature increases. This means that the ensilicated protein can be stored and transported without the cold chain. Here we propose the modification and use of our Ensilication method to improve the long-term thermal stability of bacteriophages K and MS2 at room temperature. Analytical techniques and in vitro bacterial culture will verify the ability and efficacy of the Ensilication method. We believe that the results from this study will prevent the need for cold chain of transportation and storage normally required for the use of bacteriophage therapeutics. In addition to this, we aim to visualise the Ensilication process for the first time, using electron microscopy.
The data shows how bacteriophages were ensilicated and stored for long periods of time at room temperature while retaining their infectivity. Across the study phage K showed a loss of approximately 4 log in concentration. Considering how unstable the phages are at room temperature, both the ensilicated phages showed much greater resilience to extreme temperatures. No additional loss of titre after being heated at 90 ˚C for 30 minutes was observed when compared to loss already known from the Ensilication process.
Although Ensilication results in an immediate loss of 4 log titre of the ensilicated bacteriophage, the survival of the phages at room temperature compared to native lysates proves that ensilicated samples can remain viable for use for extended periods of time without refrigeration.