Polymeric gene delivery system

Abstract

A means for obtaining efficient introduction of exogenous genes into a patient, with long term expression of the gene, is disclosed. The gene, under control of an appropriate promoter for expression in a particular cell type, is encapsulated or dispersed with a biocompatible, preferably biodegradable polymeric matrix, where the gene is able to diffuse out of the matrix over an extended period of time, for example, a period of three to twelve months or longer. The matrix is preferably in the form of a microparticle such as a microsphere (where the gene is dispersed throughout a solid polymeric matrix) or microcapsule (gene is stored in the core of a polymeric shell), a film, an implant, or a coating on a device such as a stent. The size and composition of the polymeric device is selected to result in favorable release kinetics in tissue. The size is also selected according to the method of delivery which is to be used, typically injection or administration of a suspension by aerosol into the nasal and/or pulmonary areas. The matrix composition can be selected to not only have favorable degradation rates, but to be formed of a material which is bioadhesive, to further increase the effectiveness of transfer when administered to a mucosal surface.

1 . A method of transfecting cells in vitro in culture medium comprising contacting cells in a culture medium with a composition for delivery of naked DNA, said composition comprising: 
 (a) a preparation of microparticles between 1 and 300 μm in diameter, each of which preparation of microparticles comprises a synthetic, biocompatible, biodegradable polymeric matrix; and    (b) an effective amount of naked DNA dispersed within the preparation of microparticles, wherein said amount of naked DNA is greater than 20 μg, in which the DNA contains a gene operably linked to a promoter, the nucleotide sequence of said gene being greater than thirty nucleotides in length;    wherein said DNA is released or diffused from said matrix over a period of at least three months.    
     
     
         2 . A method of transfecting cells in vitro in culture medium comprising contacting cells in a culture medium with a composition for delivery of naked DNA, said composition comprising: 
 (a) a preparation of microparticles between 1 and 300 μm in diameter, each of which preparation of microparticles comprises a synthetic, biocompatible, non-biodegradable polymeric matrix; and    (b) an effective amount of naked DNA dispersed within the preparation of microparticles, wherein said amount of naked DNA is greater than 20 μg, in which the DNA contains a gene operably linked to a promoter, the nucleotide sequence of said gene being greater than thirty nucleotides in length;    wherein said DNA releases or diffuses from said matrix over a period of at least three months.