Figure 1. Sketch of a cell and the mimic of its plasma membrane as a flat model. Figure 2. AFM images of the formation of domains in the raft SLB mimic, deposited on mica, following the formation of the more ordered solid domains within the disordered phase, upon increasing the temperature: (a) 17 °C, (b) 21 °C, (c) 23 °C, (d) 25 °C, (e) 27 °C, (f) 27.5 °C, (g) 28 °C, (h) 28.5 °C, (i) 29 °C, (j) 29.5 °C, (k) 30 °C, (l) 31 °C, field size = 1.5x1.5 μm, scale bar: 0.5 μm. Figure 3. Scattering length density (SLD) profiles of the main dRaft SLB at all measured temperatures in D2O showing (a) SLD profiles of the dRaft membrane at 37 °C in red, 31 °C in orange, 25 °C in yellow, 21 °C in green, and 17 °C in blue. (b) Graphic sketch to guide the eye in assessing the correspondence between hydrophilic head and hydrophobic tail regions of the SLB and its SLD profile. Figure 4. Deconvolution of the DSC thermogram of the dRaft model membrane. Data were collected with a scan rate of 1 °C/3 min, in cooling mode. Blue circles show the full bilayer thickness, green squares show the hydrophobic bilayer thickness measured by NR while cooling at temperatures of 37, 31, 25, 21, 17 °C. S. Helmy1,2, P. Parisse3,4, L. Casalis4, V. Rondelli1 1 Department of Medical Biotechnology and Translational Medicine, Università Degli Studi di Milano Milano, Italy 2 Biophysics Group, Physics Department, Faculty of Science, Ain Shams University, Cairo Egypt (Present address) 3 Elettra Sincrotrone Trieste, Basovizza, TS, Italy 4 CNR-IOM, Basovizza, TS, Italy e-mail: valeria.rondelli@unimi.it; casalis@elettra.eu Acknowledgments This work has received funding from the cultural affairs and missions sector of the Ministry of Higher Education in Egypt, PhD scholarship mission 2019/2020 to S.H. The Italian Ministry of University and Research, PRIN2020 project n. 2020MHL8S9 “MITHOS” to V.R. The European Union – Next Generation EU Missione 4 Componente 2, project n. P2022J2ZC2 (CUP: G53D23007030001) to V.R. and P.P. The European Union – Next Generation EU Missione 4 Componente 2, project n. 20223SM7T2 (CUP: G53D23003300001) to V.R. The European Union – NextGenerationEU, project PNRR "PRP@ CERIC" IR0000028. This work benefited from the use of the Offspec vertical neutron reflectometer beamtime; DOI: 10.5286/ISIS.E.RB2210183 at the ISIS Neutron and Muon Source, Oxfordshire, UK. This work also benefited from the use of the anaklasis, an open-source Python3 scripts provided by Alexandros Koutsioubas. Original paper S. Helmy et al., JCIS, 690 (2025); DOI:10.1016/j.jcis.2025.137333. Fig. 4 Fig. 2 17°C 21°C 23°C 25°C 27°C 27.5°C 28°C 28.5°C 29°C 29.5°C 30°C 31°C (a) (b) (c) (d) (e) (f) (g) (h) (i) (j) (k) (l) 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 -5.00 -4.00 -3.00 -2.00 -1.00 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 nm (2) Fig. 3 (3) (4) (1) Fig. 1 Low density and soft matter Elettra Highlights 2024–2025 47
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