Chen YC(1), Smith T(2), Hicks RH(2), Doekhie A(1), Koumanov F(3), Wells SA(4), Edler KJ(1), van den Elsen J(3), Holman GD(3), Marchbank KJ(5), Sartbaeva A(1).
(1) Department of Chemistry, Claverton Down, Bath, BA2 7AY, UK.
(2) Centre for Sustainable Chemical Technologies, Bath, BA2 7AY, UK.
(3) Department of Biology and Biochemistry, Claverton Down, Bath, BA2 7AY, UK.
(4) Department of Chemical Engineering, University of Bath, Bath, BA2 7AY, UK.
(5) The Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK.
Biological substances based on proteins, including vaccines, antibodies, and enzymes, typically degrade at room temperature over time due to denaturation, as proteins unfold with loss of secondary and tertiary structure. Their storage and distribution therefore relies on a “cold chain” of continuous refrigeration; this is costly and not always effective, as any break in the chain leads to rapid loss of effectiveness and potency. Efforts have been made to make vaccines thermally stable using treatments including freeze-drying (lyophilisation), biomineralisation, and encapsulation in sugar glass and organic polymers. Here for the first time we show that proteins can be enclosed in a deposited silica “cage”, rendering them stable against denaturing thermal treatment and long-term ambient-temperature storage, and subsequently released into solution with their structure and function intact. This “ensilication” method produces a storable solid protein-loaded material without the need for desiccation or freeze-drying. Ensilication offers the prospect of a solution to the “cold chain” problem for biological materials, in particular for vaccines.
PMID: 28436442 [Indexed for MEDLINE]