Biological selection of peptides for poly(l-lactide) substrates

Area of Science:

• Biomaterials Science
• Peptide Chemistry
• Polymer Crystallography

Background:

• Poly(L-lactide) (PLLA) is a biodegradable polymer with various crystalline forms.
• Recognizing specific PLLA polymorphs is crucial for controlling material properties and applications.
• Phage display is a powerful technique for identifying specific binding molecules.

Purpose of the Study:

• To identify short peptides that specifically recognize the alpha form of PLLA crystalline films.
• To elucidate the binding interactions between the identified peptides and PLLA polymorphs.
• To assess the specificity of peptide binding against similar polymers and PLLA amorphous/beta forms.

Main Methods:

• Phage display library screening to identify PLLA-binding peptides.
• Enzyme-linked immunosorbent assay (ELISA) to quantify binding affinities.
• Surface plasmon resonance (SPR) analysis to determine binding kinetics and specificity.
• Amino acid sequence analysis of selected peptides.

Main Results:

• Specific heptapeptides recognizing the alpha form of PLLA were identified.
• Selected phage clones showed significantly higher binding constants for alpha-PLLA compared to unselected phage.
• Peptide sequences were enriched in amino acids suggesting hydrogen bonding and hydrophobic interactions.
• The c22 heptapeptide demonstrated specific binding to alpha-PLLA over at-PMMA, amorphous PLLA, and beta-PLLA.

Conclusions:

• Short peptides can be selected to specifically recognize PLLA crystalline polymorphs.
• The binding mechanism involves a combination of hydrogen bonding and hydrophobic interactions.
• The c22 peptide exhibits high specificity, distinguishing subtle differences in PLLA crystalline structures.