Lateral remodeling of phase-separated membranes containing 3-OH-blocked azo-sphingolipids upon light trigger analyzed by high-speed AFM. (A) Changes in the area of Lo domains (of depicted snapshots) before/after illumination with UV-A (λ = 365 nm) and blue (λ = 470 nm) lights on DOPC:Chol:SM:photolipid (10:6.7:5:5 mol ratio) SLBs having Azo-THP-SM (see Video S7) or Azo-THP-Cer (see Video S8) with a 3-OH-blocked (THP-protected) sphingosine backbone and varying headgroup functionality (R = phosphocholine or –OH, respectively). (B and C) Reversible lateral remodeling of a phase-separated SLB with Azo-THP-SM (DOPC:Chol:SM:Azo-THP-SM; 10:6.7:5:5 mol ratio) upon UV-A/blue light irradiation, as seen in Video S9. (B) AFM images of the SLB at the dark-, UV-, and blue light-adapted states, displaying the area occupied by the Lo phase and the Ld-Lo height mismatches. (C) Relative variation of total Lo area of the SLB over time, shown in Video S9, upon shining short pulses (marked with arrows) of UV-A and blue light. To see this figure in color, go online.