Determination of pH Effects on Phosphatidyl-Hydroxytyrosol and Phosphatidyl-Tyrosol Bilayer Behavior

Methods and Protocols

Appell, Michael¹  Compton, DavidL.²  Evans, KervinO.³ 

[1] Author to whom correspondence should be addressed.;Mycotoxin Prevention and Applied Microbiology, United States Department of Agriculture Research Service, National Center for Agricultural Utilization Research, 1815 N. University Street, Peoria, IL 61604, USA;Renewable Product Technology Research Unit, United States Department of Agriculture Research Service, National Center for Agricultural Utilization Research, 1815 N. University Street, Peoria, IL 61604, USA

关键词: method application;    bilayer;    phospholipid;    dynamic light scattering;    zeta potential;   

DOI  :  10.3390/mps1040041

学科分类：生物技术

来源: mdpi

【 摘 要 】

A robust method was developed to investigate the liposomal behavior of novel enzymatically-synthesized hydroxytyrosol and tyrosol phospholipids. Bilayer characteristic obtained by this method, including bilayer formation stability and adsorption properties, were explored using dynamic light scattering, zeta-potential measurements, and quartz crystal microbalance with dissipation monitoring (QCMD), respectively. Liposome diameters were found to typically increase from pH 5.5 to pH 10. Zeta potentials values, on the other hand, were found to be well below −25 mV at all pH conditions explored, with the lowest values (and thus, the best liposome stability) at pH 5.5 or pH 10. Quartz crystal microbalance with dissipation monitoring measurements demonstrated that 100% 1,2-dioloeoylphosphatidyl-hydroxytyrosol (DOPHT) liposomes adsorbed intact onto silica in buffer conditions at pH 5.5 and with no calcium, or at pH 7.5 with calcium (no adsorption was detected at pH 10). 1,2-Dioleoylphosphatidyl-tyrosol (DOPT) liposomes were shown to adsorb intact under buffer conditions only at pH 5.5 with and without calcium. 1,2-Dioleoylphosphatidyl-2-phenolethanol (DOPPE), in comparison, readily adsorbed intact at pH 7.5 without calcium and just slightly at pH 5.5 with calcium present, but formed a supported bilayer over hours at pH 5.5 in the absence of calcium ions.

【 授权许可】

CC BY