Controlled release liposomes and methods of use

1 . A liposome comprising a trigger polypeptide, a lipid layer, and a compartment surrounded by the lipid layer,

wherein the lipid layer comprises saturated lipids and unsaturated lipids,

wherein a plurality of the saturated lipids comprise a trigger polypeptide,

and wherein three trigger polypeptides form a triple helix.

2 . The liposome of claim 1 wherein the unsaturated lipid is polymerized.

3 . The liposome of claim 1 wherein the triggering polypeptide comprises an amino acid repeat region.

4 . The liposome of claim 1 wherein the amino acid repeat region comprises (GPX)n, wherein X is 4-hydroxyproline, proline, or a homolog thereof, and n is at least 3.

5 . The liposome of claim 1 wherein the triggering polypeptide comprises a peptide bond that is cleaved by a gelatinase-A.

6 . The liposome of claim 1 wherein the triggering polypeptide comprises a peptide bond that is cleaved by a gelatinase-B.

7 . The liposome of claim 1 wherein the compartment comprises a compound.

8 . The liposome of claim 7 wherein the compound is an inhibitor of gelatinase-A, gelatinase-B, or the combination thereof.

9 . A composition comprising the liposome of claim 1 and a pharmaceutically acceptable carrier.

10 . A liposome comprising a trigger polypeptide, a lipid layer, and a compartment surrounded by the lipid layer,

wherein the lipid layer comprises polymerized saturated lipids and unsaturated lipids,

wherein a plurality of the saturated lipids comprise a trigger polypeptide,

wherein the compartment comprises a compound,

and wherein cleavage of a peptide bond within the trigger polypeptide results in release of the compound from the liposome.

11 . The liposome of claim 10 wherein three trigger polypeptides form a triple helix.

12 . A composition comprising the liposome of claim 10 and a pharmaceutically acceptable carrier.

13 . A method for inhibiting activity of an enzyme comprising:

providing a liposome comprising a trigger polypeptide present on the surface of the liposome, a lipid layer, and a compartment surrounded by the lipid layer, wherein the trigger polypeptide comprises a peptide bond that is cleaved by a first enzyme, wherein three trigger polypeptides form a triple helix, and wherein the compartment comprises an inhibitor of a second enzyme;

exposing the liposome to the enzyme, wherein the first enzyme cleaves the peptide bond and the liposome releases the inhibitor, and wherein the inhibitor inhibits the activity of the second enzyme.

14 . The method of claim 13 wherein the first and second enzymes are present in vivo.

15 . The method of claim 13 wherein first and second enzymes are gelatinase-A or gelatinase-B.

16 . A method for treating a disease comprising:

administering to a patient having or at risk of having a disease an effective amount of a composition comprising a liposome, wherein the liposome comprises a targeting polypeptide present on the surface of the liposome, a lipid layer, and a compartment surrounded by the lipid layer, wherein the targeting polypeptide comprises a peptide bond that is cleaved by an enzyme, wherein three trigger polypeptides form a triple helix, and wherein the compartment comprises a compound; and

decreasing a symptom of the disease.

17 . The method of claim 16 wherein the compound is an inhibitor of the enzyme.

18 . The method of claim 16 wherein the enzyme is gelatinase-A or gelatinasae-B.

19 . A method for detecting an enzyme comprising:

administering to a patient an effective amount of a composition comprising a liposome, wherein the liposome comprises a targeting polypeptide present on the surface of the liposome, a lipid layer, and a compartment surrounded by the lipid layer, wherein the targeting polypeptide comprises a peptide bond that is cleaved by an enzyme, wherein three trigger polypeptides form a triple helix, and wherein the compartment comprises an imaging compound; and

detecting the presence of the imaging compound in the patient.