Controlled molecular organization of surface macromolecular assemblies based on stimuli-responsive polypeptide...

Area of Science:

• Surface Science
• Polymer Chemistry
• Biomaterials Science

Background:

• Polyelectrolyte complex formation is crucial for surface modification.
• Controlling macromolecular organization on surfaces is challenging.
• Understanding secondary polymer conformations impacts material properties.

Purpose of the Study:

• To create reversible polyelectrolyte complex films at neutral pH.
• To investigate how anionic polymers influence poly(L-lysine) brush conformation.
• To correlate film structure with thickness and morphology.

Main Methods:

• Utilized end-tethered poly(L-lysine) (t-PLL) and anionic polymers (PAA, PLGA, PLAA).
• Employed in situ zeta-potential, fluorescence imaging, circular dichroism, and FTIR for characterization.
• Performed ellipsometry and atomic force microscopy for thickness and morphology studies.

Main Results:

• Successfully formed reversible polyelectrolyte complex films at neutral pH.
• Demonstrated that t-PLL adopted alpha-helical, beta-sheet, or random coil structures depending on the anionic polymer.
• Observed reduced solvated film thickness due to compact structures, influenced more by secondary structure than adsorbed mass.

Conclusions:

• The secondary conformations of t-PLL complex films are dictated by the specific polyanion used.
• Dilute acid rinses can restore the original t-PLL structure.
• This approach offers a biomimetic strategy for controlling surface macromolecular assemblies and modeling protein complexes.