Growth Factor-Bearing Polymer Brushes--Versatile Bioactive Substrates Influencing Cell Response

Area of Science:

• Biomaterials Science
• Cell Biology
• Surface Chemistry

Background:

• Developing advanced cell culture substrates is crucial for regenerative medicine and biological research.
• Controlling cell behavior requires precise presentation of bioactive cues.
• Polymer brushes offer a versatile platform for surface modification and biomolecule immobilization.

Purpose of the Study:

• To develop responsive nanoscale substrates with cell-guiding properties using bioactive signaling cues.
• To investigate the effect of surface-bound hepatocyte growth factor (HGF) and basic fibroblast growth factor (bFGF) on cell behavior.
• To compare physisorption and chemisorption strategies for growth factor immobilization on poly(acrylic)acid (PAA) polymer brushes.

Main Methods:

• Fabrication of dense poly(acrylic)acid (PAA) polymer brush films.
• Biofunctionalization of PAA brushes with HGF and bFGF via physisorption and chemisorption.
• Characterization of growth factor release kinetics.
• Assessment of cell response (growth inhibition, scattering, differentiation) on modified substrates using HepG2 cells and mouse embryonic stem cells (mESCs).

Main Results:

• Both physisorption and chemisorption achieved high growth factor binding efficiencies.
• Physisorbed GFs showed an initial burst release, followed by slow release.
• Chemisorbed HGF exhibited sustained binding (>1 week), while chemisorbed bFGF showed slow release.
• GF-functionalized PAA brushes demonstrated measurable effects on HepG2 cell growth inhibition/scattering and mESC differentiation.

Conclusions:

• PAA polymer brushes can be effectively biofunctionalized with GFs using both physisorption and chemisorption.
• Chemisorption provides enhanced control over GF release kinetics and surface retention.
• GF-modified PAA brushes serve as versatile bioactive cell culture substrates with tunable efficiency for specific cell responses.