Receptor-binding ligands have been incorporated into DNA/ @entity12279 ( @entity8681 ) complexes to enhance cell binding and cellular internalization. This study characterizes receptor-mediated uptake of DNA/ @entity8681 complexes on a cellular basis. A novel assay based on flow cytometry was applied, discriminating between total cell-associated and extracellularly bound DNA complexes. Receptor-mediated uptake of ligand-containing DNA/ @entity8681 (molecular weight, 800 kd) complexes was found to occur quickly (within 1 hour), whereas unspecific uptake through adsorptive endocytosis is less efficient or requires extended periods to reach the same degree of internalization. Rapid, receptor-mediated internalization requires a small complex size; however, large, aggregated complexes show higher gene expression. Using @entity8681 25 kd conjugated to large proteins such as @entity69 or antibodies, improper condensation with DNA leads to suboptimal uptake and gene expression, whereas partial replacement of ligand- @entity8681 with unconjugated @entity8681 increases both uptake and transfection. In contrast, the 8 kd protein @entity4179 conjugated to @entity8681 25 kd properly condenses DNA and mediates specific uptake into @entity1 @entity420 ( @entity13892 ) cells. Modification of the complex surface with appropriate amounts of @entity968 ( @entity970 ) does not block ligand-mediated internalization. A higher degree of PEGylation reduces the internalization of @entity69 or antibody-containing complexes to a level similar to that of ligand-free complexes. In contrast, @entity4179 "mediated uptake is less effected by excessive PEGylation.

DNA/ XXXX transfection particles: influence of ligands, polymer size, and PEGylation on internalization and gene expression.

@entity1 :: ('9606', 'Species') :: ['human'] @entity12279 :: ('MESH:D011094', 'Chemical') :: ['polyethylenimine'] @entity69 :: ('7018', 'Gene') :: ['transferrin'] @entity13892 :: ('OMIM:300845', 'Disease') :: ['KB'] @entity4179 :: ('1950', 'Gene') :: ['epidermal growth factor'] @entity8681 :: ('CHEBI:53231', 'Chemical') :: ['PEI'] @entity420 :: ('MESH:D000230', 'Disease') :: ['adenocarcinoma'] @entity970 :: ('CHEBI:46793', 'Chemical') :: ['PEG'] @entity968 :: ('MESH:D011092', 'Chemical') :: ['poly(ethylene glycol)']
@entity12279 :: (MESH:D011094,Chemical) :: ['polyethylenimine']
