Polycation-Functionalized Nanoporous Silicon Carrier for Systemic Delivery of Gene Silencing Agents

Abstract

Disclosed are methods and compositions containing functionalized nanoporous silicon particles, useful in a variety of diagnostic and/or therapeutic regimens for delivery of genetic constructs to one or more cells, tissues, and/or organs of interest. Also provided are methods for introducing into selected host cells one or more selected nucleic acid molecules. The present disclosure is also directed to a method of treating a tumor, comprising the step of administering to an individual one or more of the compositions and formulations thereof as described herein.

What is claimed is: 
     
         1 . A composition for the sustained-release delivery of an active agent to a population of target cells within a mammalian subject, comprising:
 (a) a population of polycation-functionalized, nanoporous, silicon first-stage particles; and   (b) a population of second-stage particles contained substantially within the interior of the population of the first-stage particles, and wherein the second-stage particles comprise a first active agent;   
       wherein the first active agent is released from the second-stage particles, and self-assembles into one or more nanoparticles, upon contacting an aqueous environment; 
       wherein the polycation is operably linked to a first portion of the outer surface of the population of first-stage particles by conjugation or by functionalization with one or more compounds; and 
       further wherein the composition is formulated for storage between about 0° C. and about 22° C. for a period of about one week to about six months without substantial degradation, and without a substantial loss of biological activity. 
     
     
         2 . The composition of  claim 1 , wherein the population of first-stage, nanoporous silicon particles is biocompatible and degradable. 
     
     
         3 . The composition of  claim 1 , formulated for freezing, freeze-drying, dehydration, desiccation, or lyophilization. 
     
     
         4 . The composition of  claim 1 , formulated for mammalian administration. 
     
     
         5 . The composition of  claim 4 , formulated for system administration to a human. 
     
     
         6 . The composition of  claim 1 , wherein a majority of the first-stage nanoporous silicon particles are substantially discoidal, spheroidal, non-spheroidal, or oblate spheroidal in shape, or any combination thereof. 
     
     
         7 . The composition of  claim 1 , wherein a majority of the first-stage nanoporous silicon particles are substantially discoidal in shape. 
     
     
         8 . The composition of  claim 1 , wherein the first-stage nanoporous silicon particles have an average diameter of about 60 nm to about 3 microns. 
     
     
         9 . The composition of  claim 1 , wherein the first-stage nanoporous silicon particles are permeant to at least one biological barrier selected from the group consisting of a hemo-rheology barrier, a reticulo-endothelial barrier, a blood brain barrier, a tumor associated osmotic interstitial pressure barrier, an ionic and molecular pump barrier, a cell membrane barrier, an enzymatic degradation barrier, and a nuclear membrane barrier. 
     
     
         10 . The composition of  claim 1 , wherein the first-stage nanoporous silicon particles further comprise at least one targeting moiety localized to one or more regions of the outer surface of the particles. 
     
     
         11 . The composition of  claim 10 , wherein the targeting moiety specifically binds to one or more proteins or ligands on or about the surface of a selected target mammalian cell. 
     
     
         12 . The composition of  claim 11 , wherein the targeting moiety is selected from the group consisting of an antibody, an antibody fragment, a peptide, an aptamer, a small molecule, a protein, a carbohydrate, a lipid, a lipoprotein, and any combination thereof. 
     
     
         13 . The composition of  claim 1 , wherein the second-stage particles comprise at least one active agent selected from the group consisting of a therapeutic agent, a cytotoxic agent, a chemotherapeutic agent, an anti-inflammatory agent, a diagnostic agent, a gene silencing agent, and any combination thereof. 
     
     
         14 . The composition of  claim 13 , where the therapeutic agent is selected from the group consisting of a gene, a nucleic acid, an shRNA, an siRNA, a microRNA, a DNA fragment, an RNA fragment, a plasmid, a drug, a small molecule, a chemotherapeutic, a cytotoxic agent, and any combination thereof. 
     
     
         15 . The composition of  claim 1 , where the second-stage particle further comprises a second active agent. 
     
     
         16 . The composition of  claim 1 , wherein the first-stage nanoporous silicon particle undergoes physiological degradation in a target mammalian cell thereby releasing the population of second-stage particles contained there within. 
     
     
         17 . The composition of  claim 1 , formulated for freezing, freeze-drying, dehydration, desiccation, or lyophilization. 
     
     
         18 . The composition of  claim 1 , wherein the polycation comprises poly-arginine, poly-lysine, chitosan, dendrimer, polyethyleneimine, or any combination thereof. 
     
     
         19 . A method of targeting gene silencing in a mammalian cancer cell, comprising administering to a mammal, an effective amount of the composition of  claim 1 . 
     
     
         20 . A method of treating, alleviating, or ameliorating at least one symptom of cancer in a mammal, the method comprising administering to the mammal a composition comprising a therapeutically-effective amount of the composition of  claim 1 , and for a time effective to treat or ameliorate at least one symptom of the cancer. 
     
     
         21 . The method of  claim 20 , further comprising administering to the mammal an effective amount of a therapeutic agent selected from the group consisting of a small interfering RNA, an anti-cancer agent, an anti-inflammatory agent, a cytotoxic agent, or any combination thereof. 
     
     
         22 . The method of  claim 20 , wherein the mammal is human, the cancer is breast cancer, or both.