Abstract: The novel uses of the phospholipid-coated microcrystal in the delivery of water-soluble biomolecules such as polypeptides and proteins. The proteins are rendered insoluble by complexation and the resulting material forms the solid core of the phospholipid-coated particle. Alternatively, the proteins, bio-molecules or drugs can be entrapped in water-soluble form between the membranous layers of the coated microcrystal. All types of phospholipid microcrystals can incorporate 5 nm to 10 um diameter iron oxide particles to allow for manipulation by magnetic fields. Water-soluble bio-molecules including proteins, peptides, and drugs can be entrapped and retained with long shelf life in liposomes at high concentrations, provided that the phospholipid concentration is greater than 10% (w/v) such that greater than 50% of the system volume is enclosed within phospholipid membranes. Both the phospholipid-coated microcrystal and the phospholipid-coated microdroplet can be used as vaccine adjuvants.