engleski

Complexation of DNA with poly(diallyldimethylammonium chloride)

Interactions between DNA and a positively charged polyelectrolyte (polycation, PC) in solution could, in the appropriate experimental conditions (i.e. pH, ionic strength, etc.), lead to the formation of DNA-PC complexes. The investigation of such complexes is important due to the possible application of these chemical constructs as vectors for DNA transfection [1]. In this study we examined the interactions between aqueous solutions of deoxyribonucleic acid sodium salt from salmon testes and poly(diallyldimethylammonium chloride) (PDADMAC) as the model system for the formation of DNA-PC complexes. The effect of ionic strength (i.e. phosphate buffer concentration being), DNA concentration and PDADMAC chain length (i.e. molar mass being Mw = 100000 - 200000 g mol-1 and Mw = 400000 – 500000 g mol-1) on the formation of DNA-PDADMAC complexes was investigated at pH = 6.8 and t = 25 ºC. The experimental methods used were conductometric titrations, electrophoretic mobility measurements (i.e. zeta potential determination) [2, 3] and particle size measurements [3]. Our results confirm that the applied methods are useful in the process of investigation of DNA-polyelectrolyte complexes. It was observed that the effect of both ionic strength as well as DNA concentration on the process of DNA-PDADMAC complex formation should not be underestimated and that the charge ratios of PDADMAC to DNA strongly influence the properties of formed complexes.

complexation ; DNA ; poly(diallyldimethylammonium chloride)

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