Internally fixed lipid vesicle

A method of generating an internally fixed lipid vesicle, comprising:

• 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;
• permeabilizing the precursor lipid membrane transiently to generate a permeable vesicle;
• 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;
• allowing the permeable vesicle to return to a non-permeable vesicle;
• removing any extravesicular crosslinker;
• and
• 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, and wherein the internally fixed lipid vesicle has a lipid membrane that 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.