Modular targeted liposomal delivery system

Abstract

A liposome including a fusogenic liposome, a linking moiety and a targeting moiety. The fusogenic liposome is a lipid bilayer encapsulating contents. The linking moiety is electrostatically bound to the lipid bilayer, and the targeting moiety is covalently bound to the linking moiety. The liposome may also include a stabilizing moiety interposed between the linking and targeting moieties, and covalently bound to both. Alternatively, the stabilizing and targeting moieties may be covalently bound to separate linking moieties, the linking moieties being electrostatically bound to the lipid bilayer.

1 - 9 . (canceled)  
   
   
       10 . A method of introducing a bioactive agent into the cytoplasm of a cell, said method comprising: 
 a) preparing a fusogenic liposome, said fusogenic liposome comprising a lipid bilayer encapsulating a bioactive agent;    b) electrostatically linking a targeting moiety to said fusogenic liposome through a linking moiety to form a targeted liposome;    c) contacting said targeted liposome with a cell;    d) dissociating said targeting moiety from at least a portion of the lipid bilayer of said targeted liposome to form an exposed lipid bilayer portion;    e) interacting said exposed lipid bilayer portion of said targeted liposome with the membrane of said endosome such that said bioactive agent is released into the cytoplasm of said cell.    
   
   
       11 . The method of  claim 10 , further comprising the steps of electrostatically linking a stabilizing moiety to said fusogenic liposome, and dissociating said stabilizing moiety from said at least a portion of the lipid bilayer contemporaneously with said dissociating of said targeting moiety.  
   
   
       12 . (canceled)  
   
   
       13 . The method of claim  1   1 , wherein said stabilizing moiety is at least one moiety selected from the group consisting of polyethylene glycol, polyvinylpyrolidone, a dextran, a polyamino acid, methyl-polyoxazoline, polyglycerol, poly(acryloyl morpholine), and polyacrylamide.  
   
   
       14 . The method of  claim 10 , wherein the lipid bilayer comprises an N-acylphosphatidylethanolamine (NAPE).  
   
   
       15 . The method of  claim 10 , wherein said targeting moiety is at least one moiety selected from the group consisting of a vitamin, transferrin, an antibody, sialyl Lewis X antigen, hyaluronic acid, mannose derivatives, glucose derivatives, cell specific lectins, galaptin, galectin, lactosylceramide, a steroid derivative, an RGD sequence, EGF, EGF-binding peptide, urokiase receptor binding peptide, a thrombospondin-derived peptide, an albumin derivative and a combinatorial molecule.  
   
   
       16 . The method of claims  10 , wherein said linking moiety is at least one moiety selected from the group consisting of polylysine, protamine, polyethyleneimine, polyarginine, polyacrylate, a spermine derivative, cytochrome c, an annexin, heparin sulfate, an aminodextran, polyaspartate, polyglutamate, a polysialic acid, and poly(2-ethylacrylic acid).  
   
   
       17 . The method of  claim 10 , wherein the bioactive agent is selected from the group consisting of a nucleic acid, an antiviral agent, an antibacterial agent, an antifungal agent, an antimetabolic agent, an antineoplastic agent, a sterol, a carbohydrate, an amino acid, a peptides, a protein, a dye, a radiolabel, a radiopaque compound, a fluorescent compound, a mydriatic compound, a bronchodilator and a local anesthetic.  
   
   
       18 . The method of  claim 16 , wherein the bioactive agent is a condensed nucleic acid.