# LCI Engineering for Improved Polystyrene Binding: The Impact of Aromatic Amino Acid Substitutions

## TL;DR

This study improves a peptide's ability to bind to polystyrene by substituting amino acids, leading to better surface coverage and potential industrial applications.

## Contribution

Systematic exploration of aromatic amino acid substitutions in LCI to enhance polystyrene binding and surface coverage.

## Key findings

- LCI-L4H variant showed improved polystyrene binding with increased surface coverage of approximately 82%.
- Molecular dynamics simulations revealed LCI-L4H interacts more frequently with polystyrene through π–π interactions.
- 56 substitutions across 32 positions of LCI improved PS binding, with LCI-L4H being the most effective.

## Abstract

Polystyrene (PS) is a widely used synthetic polymer with
applications
in biosensing, medical devices, and packaging. PS often requires surface
modifications to enhance biocompatibility, adhesion, and chemical
functionality. Material-binding peptides (MBPs) provide a biobased
and scalable approach for PS functionalization. Therefore, optimizing
their binding properties can ensure stable and efficient binding under
industrial application conditions. In this study, we systematically
explored how aromatic amino acid substitutions (His, Phe, Trp, and
Tyr) affect the PS binding ability of the MBP named liquid chromatography
peak I (LCI). A total of 178 aromatic amino acid substitutions were
evaluated across all 47 positions of LCI, resulting in the identification
of 56 substitutions across 32 positions that improved the PS binding.
Among these, the LCI-L4H variant showed the most impoved binding to
PS and was further biophysically characterized to determine the surface
coverage by surface plasmon resonance (SPR). SPR analysis showed that
L4H increased the coating density from 7.90 to 9.18 pmol/cm2 (5.52 × 1012 molecules/cm2), which corresponds
to surface coverage of approximately 82%. Molecular dynamics (MD)
simulations revealed that the LCI-L4H variant is more compact in size
and interacts more frequently through π–π interactions
with PS. The high surface coverage and the diversity of the provided
functional groups of LCI make the MBP-binding coating a promising
alternative to chemical or physical methodologies used in PS functionalization.