Properties of Mixed DOTAP−DPPC Bilayer Membranes as Reported by Differential Scanning Calorimetry and Dynamic Light Scattering Measurements

2007 ◽  
Vol 111 (33) ◽  
pp. 10032-10039 ◽  
Author(s):  
S. Cinelli ◽  
G. Onori ◽  
S. Zuzzi ◽  
F. Bordi ◽  
C. Cametti ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Scanning Calorimetry ◽  
Bilayer Membranes ◽  
Dppc Bilayer ◽  
Scattering Measurements

Phase transitions of liposomes: When light meets heat

2021 ◽  
Author(s):  
C S Velez-Saboyá ◽  
J R Guzmán-Sepúlveda ◽  
Jesus Carlos Ruiz-Suárez
Keyword(s):  
Differential Scanning Calorimetry ◽  
Phase Transitions ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Membrane Thickness ◽  
Scanning Calorimetry ◽  
Contraction Process ◽  
Exothermic Process ◽  
Gel Phase ◽  
Derivatives Of

Abstract Phase transitions of liposomes are normally studied by differential scanning calorimetry (DSC). A suspension of liposomes is subjected to an increase (decrease) of temperature and when heat is absorbed (released), the liposomes transit from a gel (liquid) to a liquid (gel) phase. This endothermic (exothermic) process takes place at a temperature called the melting temperature Tm, which is distinctive of the type of lipids forming the vesicles. The vesicles, though, also modify their size in the transition. Indeed, the thickness of the membranes decreases (increases) because carbon tails misalign (align). Concomitant with the modifications in the membrane thickness, the diameter (D) of the liposomes changes too. Therefore, when they are inspected by light, the scattered signal carries information from such dilatation (contraction) process. We performed careful experiments using dynamic light scattering (DLS) as a function of temperature to detect the size changes of different liposomes. Gaussian fits of the derivatives of the D vs T curves coincide within 1% with thermograms, which hints to the possibility of performing thermodynamic studies of lipid systems employing light.

Effect of organic and inorganic ions on the lower critical solution transition and aggregation of PNIPAM

Soft Matter ◽  
2018 ◽  
Vol 14 (38) ◽  
pp. 7818-7828 ◽  
Author(s):  
Leonor Pérez-Fuentes ◽  
Delfi Bastos-González ◽  
Jordi Faraudo ◽  
Carlos Drummond
Keyword(s):  
Differential Scanning Calorimetry ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Inorganic Ions ◽  
Hofmeister Series ◽  
Scanning Calorimetry ◽  
Thermosensitive Polymer

We have studied the effect of different ions belonging to the extended Hofmeister series on the thermosensitive polymer poly(N-isopropylacrylamide) (PNIPAM), by combining Differential Scanning Calorimetry (DSC) and Dynamic Light Scattering (DLS).

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