Internally fixed lipid vesicle

An internally fixed lipid vesicle generated by a method comprising:

• (i) providing a precursor lipid vesicle that contains an aqueous interior enclosed by a precursor lipid membrane, wherein the precursor lipid vesicle is non-permeable to a crosslinker;
• (ii) permeabilizing the precursor lipid vesicle transiently to generate a permeable vesicle;
• (iii) contacting the permeable vesicle with an inactive activatable crosslinker, whereby the inactive activated crosslinker enters the permeablized vesicle;
• (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 reaction to occur inside the non-permeable vesicle, whereby an internally fixed lipid vesicle is generated;
• wherein the internally fixed lipid vesicle has a lipid membrane that is substantially identical to the precursor lipid membrane in one or more characteristics.