MONOLAYER STUDY OF MIXTURES OF DIACETYLENIC PHOSPHATIDYLCHOLINE AND PHOSPHOLIPIDS CONTAINING METAL-CHELATING IMINODIACETIC ACID HEADGROUP

The mixing behavior of polymerizable diacetylenic phosphatidylcholine (1) with two diacetylenic phospholipids containing the iminodiacetic a cid (IDA) functionality in the headgroup region was studied at the air -water interface. All three phospholipids contained tricosa-10,12-diyn oyl acyl chains. In phospholipid 2, the choline group (-CH2-CH2-NMe(3) ) was replaced by an -CH2-CH2-N-(CH2-COOH)(2) functionality. In phosph olipid 3, the IDA unit was linked to the phosphate headgroup via a sul fonate linker, -CH2-CH2-OS(O-2)-O-CH2-CH2- Monolayers were prepared by mixing polymerizable 1,2 tricosa-10,12-diynoyl)-sn-glycero-3-phosphoc holine (1) with metal-chelating IDA phospholipids (2, 3) on a 10 mM Cu Cl2 subphase. Studies of monolayer properties of mixtures of 2 and 3 w ith 1 demonstrated that mixtures of 2 with 1 had better mixing behavio r than mixtures of phospholipids 1 and 3.