Making novel bio-interfaces through bacterial protein recrystallization on biocompatible polylactide derivative films

Area of Science:

• Biomaterials Science
• Supramolecular Chemistry
• Surface Science

Background:

• Bacterial surface proteins self-assemble into ordered S-layers.
• Polylactide derivatives are biodegradable polymers with tunable properties.
• Creating robust biomimetic protein layers on synthetic supports is challenging.

Purpose of the Study:

• To fabricate novel bio-supramolecular structures using bacterial surface protein SbpA.
• To investigate the recrystallization of SbpA on various polylactide derivatives.
• To evaluate the influence of polymer properties on S-layer formation and stability.

Main Methods:

• Recrystallization of SbpA protein on amorphous and semicrystalline polylactide derivatives (PLLA, PDLLA, PLGA, PLCL).
• Characterization using differential scanning calorimetry (DSC), tensile stress-strain tests, and atomic force microscopy (AFM).
• Quantification of protein adsorption and assembly kinetics using quartz crystal microbalance with dissipation monitoring (QCM-D).

Main Results:

• SbpA recrystallized on all polylactide substrates, forming the native S-layer P4 lattice.
• Polymer properties (T(g), Young's modulus) influenced S-protein crystal domain size but not adsorbed protein mass.
• Amorphous PLCL showed the slowest protein adsorption rate, indicating polymer mechanical properties affect kinetics.

Conclusions:

• Biodegradable polylactide derivative films are suitable supports for robust biomimetic S-protein layers.
• The study demonstrates control over S-layer formation by selecting appropriate polymer substrates.
• This work advances the development of bio-inspired materials with tailored supramolecular architectures.