Topographical pattern dynamics in passive adhesion of cell membranes

Area of Science:

• Biophysics
• Cell Biology
• Materials Science

Background:

• Cell adhesion is crucial for biological functions, often involving complex structures like focal adhesions.
• Red blood cells (RBCs) lack these complex adhesion systems and are nonmotile.
• Understanding RBC adhesion dynamics provides insights into passive cell-surface interactions.

Purpose of the Study:

• To investigate the dynamic spatial pattern formation during red blood cell adhesion to a poly-L-lysine surface.
• To determine the mechanisms underlying pattern evolution in passive cell adhesion.
• To explore the role of membrane components and surface topography in pattern formation.

Main Methods:

• Observation of red blood cell spreading and pattern formation on poly-L-lysine using fluorescence microscopy.
• Utilizing fluorescently labeled lipids (fluorescein phosphoethanolamine) and proteins (Band 3, actin) to track membrane component dynamics.
• Manipulating membrane tension and surface topography to assess their influence on pattern development.

Main Results:

• Red blood cells rapidly spread on poly-L-lysine surfaces (<1 s), with transient blister formation.
• Distinct rippled or stippled lipid patterns (<500 nm) emerge over minutes, independent of cell integrity.
• Lipid patterns correlate with Band 3 and actin perturbations, and are influenced by surface topography.

Conclusions:

• Passive red blood cells exhibit dynamic spatial pattern formation during adhesion, beyond simple electrostatic interactions.
• Pattern evolution is driven by lipid diffusion and influenced by membrane-protein interactions and surface topography.
• Adhesion involves the slow emergence of interspersed regions of strong contact and detachment, highlighting topographical control.