The use of IR spectroscopy after rehydration to follow ternary lipoplex formation and design as a metal-based DNA nanopharmaceuticals.

(Full text is available at http://www.manu.edu.mk/prilozi). IR spectroscopy was used to follow the dynamic structural transitions of the transfection competent 100 nm DNA-divalent metal cation-phospholipid ternary complex upon recognition of individual molecules engaged. The selection of small charged metal ions as complexing agents and zwitterionic L-alpha-phosphatidylcholine as an alternative to the currently used problematic cationic lipids in gene transfection is emphasized. Spectra of unbound components were compared with those of nucleic acid-lipid and lipid-metal ion binary mixtures, as well as with the ternary complex. Data obtained for carbonyl, phosphate, choline and CH groups was used for deductions of DNA-phospholipid recognition profiles, induced by Mn(2+). Ion effects were considered as dehydrations of phosphates and H-bonding of carbonyls. The possible structure of the ternary complex is discussed with its further potential to be utilized as a nonviral gene delivery formulation. Key words: DNA-lipid recognition, nucleic acid-divalent metal cation-phospholipid ternary complex, IR spectroscopy, Mn(2+), nonviral gene delivery, lipoplexes.