Method of Delivering Therapeutics and Imaging Agents to the Brain by Nanoparticles that Cross the Blood Brain Barrier

Abstract

Described herein are methods of delivering a nanoparticle to the brain of a subject by administering to the subject a nanoparticle having a nanoparticle core and a targeting agent. A variety of targeting agents may serve to promote delivery of the described nanoparticle. For example, the targeting agent may include a ligand specific for a receptor expressed by brain endothelial cells and a linker that connects the ligand to the external surface of the nanoparticle core. Additionally, the linker can promote disassociation of the ligand from the nanoparticle when inside a cell.

What is claimed: 
     
         1 . A method of delivering a nanoparticle to the brain of a subject comprising administering to the subject a nanoparticle having a nanoparticle core and a targeting agent, wherein said targeting agent includes a ligand specific for a receptor expressed by brain endothelial cells and a linker that connects the ligand to the nanoparticle core, wherein said linker causes dissociation of the ligand from the nanoparticle when inside a brain endothelial cell, and wherein said ligand is conjugated to the external surface of the nanoparticle core through the linker. 
     
     
         2 . The method of  claim 1 , wherein:
 the surface of the nanoparticle core comprises any one of cationic mucic acid polymers (cMAP), poly(lactic-co-glycolic acid) (PLGA), chitosan, synthetic polymers such as polyethyleneimine, dendrimers, gold, or iron oxide;   the ligand is any one of transferrin, an antibody specific for the transferrin receptor, a polypeptide that specifically binds to the transferrin receptor, insulin, an antibody specific for the insulin receptor, a polypeptide that specifically binds to the insulin receptor, insulin-like growth factor 1, an antibody specific for the insulin-like growth factor receptor 1, a polypeptide that specifically binds to the insulin-like growth factor receptor 1, apolipoprotein E, angiopep-2, an antibody specific for low density lipoprotein receptor or lipoprotein receptor-related protein, a polypeptide that specifically binds to low density lipoprotein receptor or lipoprotein receptor-related protein; an antibody specific for diphtheria toxin receptor, or a polypeptide that specifically binds to diphtheria toxin receptor; and   the linker comprises a nitrophenyl boronic acid when unbound to the nanoparticle and a forms a nitrophenyl boronic ester when bound to the nanoparticle.   
     
     
         3 . The method of  claim 2 , wherein the nanoparticle core comprises cationic mucic acid polymer (cMAP) having the structure: 
       
         
           
           
               
               
           
         
       
       wherein m is any whole number between 5 and 50. 
     
     
         4 . The method of  claim 3 , wherein m is any one of 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or 16. 
     
     
         5 . The method of  claim 1 , wherein the linker of the targeting agent further comprises a polyethylene glycol (PEG) polymer between said nitrophenyl boronic acid and said ligand. 
     
     
         6 . The method of  claim 5 , wherein the linker has the structure: 
       
         
           
           
               
               
           
         
       
       where n is any whole number between 2 and 2000 and R is a functional group selected from a primary amine, azide, alcohol, thiol, aldehyde, or carboxylic acid. 
     
     
         7 . The method of  claim 6 , wherein the targeting agent is 
       
         
           
           
               
               
           
         
       
       and n is any whole number between 2 and 2000. 
     
     
         8 . The method of  claim 7 , wherein n is any whole number from about 110 to about 150. 
     
     
         9 . The method of  claim 1 , wherein:
 the surface of the nanoparticle core comprises poly(lactic-co-glycolic acid) (PLGA) polymers,   the ligand is any one of transferrin, an antibody specific for the transferrin receptor, a polypeptide that specifically binds to the transferrin receptor, insulin, an antibody specific for the insulin receptor, a polypeptide that specifically binds to the insulin receptor, insulin-like growth factor 1, an antibody specific for the insulin-like growth factor receptor 1, a polypeptide that specifically binds to the insulin-like growth factor receptor 1, apolipoprotein E, angiopep-2, an antibody specific for low density lipoprotein receptor or lipoprotein receptor-related protein, a polypeptide that specifically binds to low density lipoprotein receptor or lipoprotein receptor-related protein; an antibody specific for diphtheria toxin receptor, or a polypeptide that specifically binds to diphtheria toxin receptor; and   the linker comprises a PEG polymer.   
     
     
         10 . The method of  claim 9 , wherein the PEG polymer is conjugated to the ligand via a disulfide bond or a polypeptide having an enzyme cleavage site. 
     
     
         11 . The method of  claim 10 , wherein the nanoparticle core comprises PLGA having the structure: 
       
         
           
           
               
               
           
         
       
       wherein x and y are independently any whole number between 5 and 500. 
     
     
         12 . The method of  claim 11 , wherein x and y are independently any one of 40, 45, 50, 55, or 60. 
     
     
         13 . The method of  claim 12 , wherein the nanoparticle core comprising PLGA is conjugated to a PEG linker and has the structure: 
       
         
           
           
               
               
           
         
       
       and z is any whole number between 2 and 2000 and x and y are independently any whole number between 5 and 500, and R is selected from a primary amine, azide, alcohol, thiol, aldehyde, or carboxylic acid. 
     
     
         14 . The method of  claim 13 , wherein z is any whole number from about 110 to about 150 and x and y are 50. 
     
     
         15 . The method of  claim 14 , wherein the targeting agent is 
       
         
           
           
               
               
           
         
       
       and z is any whole number from about 110 to about 150 and x and y are 50. 
     
     
         16 . The method of  claim 1 , wherein:
 the surface of the nanoparticle core comprises any one of cationic mucic acid polymers (cMAP), poly(lactic-co-glycolic acid) (PLGA), chitosan, synthetic polymers such as polyethyleneimine, dendrimers, gold, or iron oxide;   the ligand is any one of transferrin, an antibody specific for the transferrin receptor, a polypeptide that specifically binds to the transferrin receptor, insulin, an antibody specific for the insulin receptor, a polypeptide that specifically binds to the insulin receptor, insulin-like growth factor 1, an antibody specific for the insulin-like growth factor receptor 1, a polypeptide that specifically binds to the insulin-like growth factor receptor 1, apolipoprotein E, angiopep-2, an antibody specific for low density lipoprotein receptor or lipoprotein receptor-related protein, a polypeptide that specifically binds to low density lipoprotein receptor or lipoprotein receptor-related protein; an antibody specific for diphtheria toxin receptor, or a polypeptide that specifically binds to diphtheria toxin receptor; and   the linker comprises a diamino ketal conjugated to PEG.   
     
     
         17 . The method of  claim 1 , wherein the linker includes a disulfide bond that can be reduced to cause dissociation of the ligand from the nanoparticle when the nanoparticle is inside a brain endothelial cell. 
     
     
         18 . The method of  claim 1 , wherein the linker includes a polypeptide or chemical bond that can be enzymatically cleaved to cause dissociation of the ligand from the nanoparticle when the nanoparticle is inside a brain endothelial cell. 
     
     
         19 . The method of  claim 1 , wherein the linker includes a hydrolyzable chemical bond that can be disrupted at low pH to cause dissociation of the ligand from the nanoparticle when the nanoparticle is inside a brain endothelial cell. 
     
     
         20 . The method of  claim 1 , wherein the linker includes a chemical bond having a pKa that can be disrupted at low pH to cause dissociation of the ligand from the nanoparticle when the nanoparticle is inside a brain endothelial cell. 
     
     
         21 . The method of  claim 19 , wherein low pH is a value from about 6.8 to about 2.0. 
     
     
         22 . The method of  claim 21 , wherein low pH is a value from about 5.5 to about 2.5. 
     
     
         23 . The method of  claim 21 , wherein low pH is a value from about 5.5 to about 4.0. 
     
     
         24 . The method of  claim 19 , wherein the surface of the nanoparticle core comprises poly(lactic-co-glycolic acid) (PLGA). 
     
     
         25 . The method of  claim 19 , wherein the surface of the nanoparticle core comprises cationic mucic acid polymers (cMAP). 
     
     
         26 . The method of  claim 19 , wherein the surface of the nanoparticle core comprises gold. 
     
     
         27 . The method of  claim 1 , wherein:
 the surface of the nanoparticle core comprises the surface of the nanoparticle core comprises any one of cationic mucic acid polymers (cMAP), poly(lactic-co-glycolic acid) (PLGA), chitosan, synthetic polymers such as polyethyleneimine, dendrimers, gold, or iron oxide;   the ligand is any one of transferrin, an antibody specific for the transferrin receptor, a polypeptide that specifically binds to the transferrin receptor, insulin, an antibody specific for the insulin receptor, a polypeptide that specifically binds to the insulin receptor, insulin-like growth factor 1, an antibody specific for the insulin-like-growth factor receptor 1; a polypeptide that specifically binds to the insulin-like growth factor receptor 1, apolipoprotein E, angiopep-2, an antibody specific for low density lipoprotein receptor or lipoprotein receptor-related protein, a polypeptide that specifically binds to low density lipoprotein receptor or lipoprotein receptor-related protein; an antibody specific for diphtheria toxin receptor, or a polypeptide that specifically binds to diphtheria toxin receptor; and   the linker comprises an acid-cleavable chemical bond selected from an orthoester, acetal, ketal, imine, or hydrazone, that is conjugated to PEG.   
     
     
         28 . The method of  claim 1 , wherein the nanoparticle comprises less than 200 targeting agents conjugated to its surface. 
     
     
         29 . The method of  claim 1 , wherein the nanoparticle comprises less than 20 targeting agents conjugated to its surface. 
     
     
         30 . The method of  claim 1 , wherein the nanoparticle comprises less than 5 targeting agents conjugated to its surface. 
     
     
         31 . The method of  claim 1 , wherein the nanoparticle comprises a single targeting agent conjugated to its surface. 
     
     
         32 . The method of  claim 1 , wherein the nanoparticle has a size of from about 40 nm to about 100 nm as measured by dynamic light scattering (DLS). 
     
     
         33 . The method of  claim 32 , wherein the nanoparticle has a size of from about 50 nm to about 70 nm as measured by dynamic light scattering (DLS). 
     
     
         34 . The method of  claim 33 , wherein the nanoparticle has a size of 55 nm, 56 nm, 57 nm, 58 nm, 59 nm, 60 nm, 61 nm, 62 nm, 63 nm, 64 nm, 65 nm, 66 nm, 67 nm, 68 nm, or 69 nm as measured by dynamic light scattering (DLS). 
     
     
         35 . The method of  claim 1 , wherein the nanoparticle has an average zeta potential of from about −0.5 mV to about −15.0 mV as measured by phase analysis light scattering. 
     
     
         36 . The method of  claim 35 , wherein the nanoparticle has an average zeta potential of −5.0, −5.1, −5.2, −5.3, −5.4, −5.5, −5.6, −5.7, −5.8, −5.9, −6.0, −6.1, −6.2, −6.3, −6.4, −6.5, −6.6, −6.7, −6.8, −6.9, −7.0, −7.1, −7.2, −7.3, −7.4, −7.5, −7.6, −7.7, −7.8, −7.9, or −8.0 mV as measured by phase analysis light scattering. 
     
     
         37 . The method of  claim 1 , wherein the nanoparticle further comprises a therapeutic agent. 
     
     
         38 . The method of  claim 37 , wherein the therapeutic agent is effective against a neurological disorder. 
     
     
         39 . The method of  claim 38 , wherein the therapeutic agent is serotonin or dopamine. 
     
     
         40 . The method of  claim 1 , wherein the nanoparticle further comprises an imaging agent. 
     
     
         41 . The method of  claim 40 , wherein the imaging agent is Cu-64. 
     
     
         42 . The method of  claim 1 , wherein the nanoparticle includes a first targeting agent and a second targeting agent, wherein the second targeting agent comprises:
 a linker that is not amenable to disassociation from the nanoparticle core when inside of a brain endothelial cell, and   a ligand that targets the particle to a specific cell in the brain.   
     
     
         43 . A kit for producing a nanoparticle targeted for delivery to the brain comprising cationic mucic acid polymers (cMAP) or poly(lactic-co-glycolic acid) (PLGA); a targeting agent specific for a receptor expressed by brain endothelial cells, wherein said targeting agent includes a ligand that is conjugated to a linker that causes dissociation of the ligand from the nanoparticle when inside a brain endothelial cell; and instructions for assembling the nanoparticle. 
     
     
         44 . The kit of  claim 43 , wherein the ligand is any one of transferrin, an antibody specific for the transferrin receptor, a polypeptide that specifically binds to the transferrin receptor, insulin, an antibody specific for the insulin receptor, a polypeptide that specifically binds to the insulin receptor, insulin-like growth factor 1, an antibody specific for the insulin-like growth factor receptor 1, a polypeptide that specifically binds to the insulin-like growth factor receptor 1, apolipoprotein E, angiopep-2, an antibody specific for low density lipoprotein receptor or lipoprotein receptor-related protein, a polypeptide that specifically binds to low density lipoprotein receptor or lipoprotein receptor-related protein; an antibody specific for diphtheria toxin receptor, or a polypeptide that specifically binds to diphtheria toxin receptor; and wherein the linker comprises a nitrophenyl boronic acid when unbound to the nanoparticle and a forms a nitrophenyl boronic ester when bound to the nanoparticle. 
     
     
         45 . The kit of  claim 44 , further comprising a therapeutic agent or an imaging agent.