title: Lipid-Detergent Phase Transitions During Detergent-Mediated Liposome Solubilization.
abstract: We investigate the phase transition stages for detergent-mediated liposome solubilization of bio-mimetic membranes with the motivation of integrating membrane-bound Photosystem I into bio-hybrid opto-electronic devices. To this end, the interaction of two non-ionic detergents n-dodecyl-β-D-maltoside (DDM) and Triton X-100 (TX-100) with two types of phospholipids, namely DPhPC (1,2-diphytanoyl-sn-glycero-3-phosphocholine) and DPPG (1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol)), are examined. Specifically, solubilization processes for large unilamellar liposomes are studied with the aid of turbidity measurements, dynamic light scattering, and cryo-transmission electron microscopy imaging. Our results indicate that the solubilization process is well depicted by a three-stage model, wherein the lamellar-to-micellar transitions for DPhPC liposomes are dictated by the critical detergent/phospholipid ratios. The solubilization of DPhPC by DDM is devoid of formation of a "gel-like" phase. Furthermore, our results indicate that DDM is a stable candidate for DPhPC solubilization and proteoliposome formation. Finally, although the solubilization of DPPG with DDM indicated the familiar three-stage process, the same process with TX-100 indicate structural deformation of vesicles into complex network of kinetically trapped micro- and nanostructured arrangements of lipid bilayers.
authors.affiliation: Sustainable Energy Education and Research Center (SEERC), University of Tennessee, Knoxville, TN, USA.|Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN, USA.
authors.forename: Hanieh
authors.initials: H
authors.lastname: Niroomand
authors.affiliation: Department of Mechanical, Aerospace and Biomedical Engineering, University of Tennessee, Knoxville, TN, USA.
authors.forename: Guru A
authors.initials: GA
authors.lastname: Venkatesan
authors.affiliation: Department of Mechanical, Aerospace and Biomedical Engineering, University of Tennessee, Knoxville, TN, USA.
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Sarles
authors.affiliation: Sustainable Energy Education and Research Center (SEERC), University of Tennessee, Knoxville, TN, USA. dmukherj@utk.edu.|Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN, USA. dmukherj@utk.edu.|Department of Mechanical, Aerospace and Biomedical Engineering, University of Tennessee, Knoxville, TN, USA. dmukherj@utk.edu.
authors.forename: Dibyendu
authors.initials: D
authors.lastname: Mukherjee
authors.affiliation: Sustainable Energy Education and Research Center (SEERC), University of Tennessee, Knoxville, TN, USA. bkhomami@utk.edu.|Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN, USA. bkhomami@utk.edu.|Department of Mechanical, Aerospace and Biomedical Engineering, University of Tennessee, Knoxville, TN, USA. bkhomami@utk.edu.
authors.forename: Bamin
authors.initials: B
authors.lastname: Khomami
mesh_terms: D003902:Detergents / Q000737:chemistry*; D008055:Lipids / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry* / Q000648:ultrastructure; D008823:Micelles; D015394:Molecular Structure; D044367:Phase Transition; D010715:Phosphatidylglycerols / Q000737:chemistry; D012995:Solubility / Q000187:drug effects; D013501:Surface-Active Agents / Q000494:pharmacology
chemical_list: D003902:Detergents; D008055:Lipids; D008081:Liposomes; D008823:Micelles; D010715:Phosphatidylglycerols; D013501:Surface-Active Agents; C030345:1,2-dipalmitoylphosphatidylglycerol
keywords: DPhPC and DPPG; Detergent-mediated liposome solubilization; Lamellar-to-complex structures; Lamellar-to-micellar transition; Transmission electron microscopy; n-dodecyl-β-D-maltoside (DDM) and Triton X-100 (TX-100)