US Patent 6902931 Controlled reversible poration for preservation of biological materials

A preservation method for biological material having cell membranes includes reversibly porating the cell membranes; loading a bio-protective agent having bio-preservation properties to a predetermined intracellular concentration; preparing the bio-protective agent loaded biological material for storage; storing the biological material; recovering the stored biological material from storage; and reversing the cell membrane poration. H5 α-toxin, a genetically engineered mutant of Staphylococcus aureus α-hemolysin, may be used as a porating agent. Non-permeating sugars such as trehalose and sucrose may be used as the bio-protective agent.