Measuring the pH environment of DNA delivered using nonviral vectors: implications for lysosomal trafficking.
The degradation of DNA in lysosomes represents a major obstacle to efficient nonviral gene delivery. The rational design of vectors that overcome this obstacle requires a better understanding of the lysosomal barrier to gene delivery, which in turn requires a means to investigate this intermediate step. To this end, we developed a technique to measure the pH environment of delivered DNA, from which the degree to which vectors avoided trafficking to acidic Iysosomes could be determined. The measured average pH of DNA delivered using poly-L-lysine (PLL) polyplexes was 4.5, suggesting that PLL polyplexes were trafficked to acidic lysosomes. Other vectors could avoid or buffer the pH of Iysosomes as DNA delivered using Lipofectamine Plus, polyethylenimine (PEI), linear polyethylenimine (LPEI), and two degradable poly(beta-amino ester)s (poly-1 and poly-2) had average pH values of 7.1, 5.9, 5.0, 6.7, and 6.4, respectively.
Department of Chemical Engineering, E25-342, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Akin
A
Akinc
Robert
R
Langer
D016475:3T3 Cells / Q000378:metabolism; D000818:Animals; D002411:Cation Exchange Resins / Q000737:chemistry; D004247:DNA / Q000737:chemistry; D016503:Drug Delivery Systems / Q000379:methods; D011992:Endosomes / Q000737:chemistry; D004867:Equipment Design; D005240:Feasibility Studies; D005434:Flow Cytometry / Q000295:instrumentation* / Q000379:methods; D005822:Genetic Vectors / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008055:Lipids / Q000737:chemistry; D008247:Lysosomes / Q000737:chemistry*; D051379:Mice; D010957:Plasmids / Q000737:chemistry*; D011091:Polyesters / Q000737:chemistry; D011094:Polyethyleneimine / Q000031:analogs & derivatives / Q000737:chemistry; D011107:Polylysine / Q000031:analogs & derivatives / Q000737:chemistry; D014162:Transfection / Q000295:instrumentation* / Q000379:methods; D014780:Viruses / Q000235:genetics
D002411:Cation Exchange Resins; D008055:Lipids; C086724:Lipofectamine; D011091:Polyesters; D011107:Polylysine; D011094:Polyethyleneimine; D004247:DNA