Abstract: Delivery systems and their methods of formation are generally provided. The delivery system can protect a delivery molecule (e.g., DNA/RNA) and deliver it into a cell via serum. In one embodiment, the method can include binding a delivery molecule with polyethylenimine such that an end of the delivery molecule is exposed; capping the end of the delivery molecule with a first biocompatible polymer to form a core; and encapsulating the core with a second biocompatible polymer. The resulting delivery system can include a delivery molecule bonded with polyethylenimine such that an end of the delivery molecule is exposed; a first biocompatible polymer electrostatically bonded to the end of the delivery molecule to form a core; and a second biocompatible polymer encapsulating the core.

Abstract: Described are charge reversible polymers, peptides and their resulting colloidal particles, comprising polymers and peptides having primary and secondary amines that are protected as easily hydrolysable amides. The amides are charge-reversible such that at neutral pH they are negatively charged but become positively charged at pH less than 6 and thus are relatively stable at neutral pH but quickly hydrolyze at pH below 6. Incorporating a drug in a micelle or a polymer comprised of the charge-reversible polymers or peptides provides a drug carrier for delivering the drug preferentially to the solid tumor or other targeted cells.

Abstract: The invention is a nanoparticle that contains an anticancer drug that is released in cancer cells when administered to a subject. The nanoparticles have a core including the anticancer drug and polymer chains that are soluble at the pH of the cancer cell. The core is surrounded by a layer of polymer chains that are insoluble at the pH of healthy tissue but soluble at the pH of the cancer interstitium. An outside layer is made of water-soluble polymer chains to shield the nanoparticle from RES recognition and give the nanoparticle a long circulation time in the bloodstream of the subject. The outside layer may also include folic acid moieties that bind folic acid receptors on the surface of the cancer cell.

Abstract: Described are charge reversible polymers, peptides and their resulting colloidal particles, comprising polymers and peptides having primary and secondary amines that are protected as easily hydrolysable amides. The amides are charge-reversible such that at neutral pH they are negatively charged but become positively charged at pH less than 6 and thus are relatively stable at neutral pH but quickly hydrolyze at pH below 6. Incorporating a drug in a micelle or a polymer comprised of the charge-reversible polymers or peptides provides a drug carrier for delivering the drug preferentially to the solid tumor or other targeted cells.