Phase behaviour of dehydrated phosphatidylcholines

• Published in: Journal of thermal analysis and calorimetry Vol. 127; no. 1; pp. 415 - 421
• Main Authors: Owusu-Ware, Samuel K., Chowdhry, Babur Z., Leharne, Stephen A., Antonijević, Milan D.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 2017; Springer; Springer Nature B.V
• Subjects: Activation energy; Analytical Chemistry; Calorimetry; Carbon; Chains; Chains (polymeric); Chemistry; Chemistry and Materials Science; Colloiding; Conversion; Dehydration; Differential scanning calorimetry; Inorganic Chemistry; Lipids; Measurement Science and Instrumentation; Molecular chains; Molecular interactions; Phospholipids; Physical Chemistry; Polymer Sciences; Dehydrated phosphatidylcholines; Phospholipids; DSC; Phase transitions
• ISSN: 1388-6150; 1588-2926; 1572-8943
• DOI: 10.1007/s10973-016-5957-x

Dehydrated DLPC, DMPC, DPPC and DSPC have been characterised at temperatures below the diacyl carbon chain-melting transition (
T
m
), using DSC. For the first time, the existence of pre-Tm transition processes, which are, usually, only observed in the colloidal/liposomal state of saturated phospholipids, has been detected for the dehydrated phosphatidylcholines. Temperature-modulated differential scanning calorimetry was used to characterise the several complexes, overlapping pre-
T
m
transition processes. Kinetic studies of the chain-melting (
T
m
) transition show the activation energy dependence on
α
(conversion rate), i.e. activation energy decreases as the transition progresses, pointing to the importance of initial cooperative (intra- and inter-molecular) mobility. Furthermore, the activation energy increases with increase in diacyl chain length of the phosphatidylcholines which supports the finding that greater molecular interactions of the polymer chain and its head groups in the dehydrated solid state lead to enhanced stability of dehydrated phosphatidylcholines.