Internally fixed lipid vesicle

An internally fixed lipid vesicle, comprising:

• a lipid membrane and a gelated interior, wherein the internally fixed lipid vesicle is generated by a process comprising:
• (i) providing a precursor lipid vesicle that contains an aqueous interior enclosed by a precursor lipid membrane, wherein the precursor lipid membrane of the precursor lipid vesicle is non-permeable to a crosslinker, the precursor lipid vesicle being an isolated cell or virus;
• (ii) permeabilizing the precursor lipid membrane transiently to generate a permeable vesicle;
• (iii) contacting the permeable vesicle with an inactive activatable crosslinker, whereby the inactive activatable crosslinker enters the permeable vesicle, wherein the inactive activatable crosslinker is a monomer or polymer;
• (iv) allowing the permeable vesicle to return to a non-permeable vesicle;
• (v) removing any extravesicular crosslinker;
• and
• (vi) activating the inactive activatable crosslinker to allow crosslinking to occur inside the non-permeable vesicle, whereby an internally fixed lipid vesicle containing a gelated interior is generated, wherein the lipid membrane of the internally fixed lipid vesicle is substantially identical to the precursor lipid membrane in one or more of membrane fluidity, membrane protein mobility, sensitivity to a surfactant, membrane permeability, membrane content, surface charge, and biological function.