Cellular Flocculation Driven by Concentrated Polymer Brush-Modified Cellulose Nanofibers with Different Surface...

Area of Science:

• Biomaterials Science
• Cell Biology
• Surface Chemistry

Background:

• Cellulose nanofibers (CNFs) are promising biomaterials for 3D cell culture.
• Controlling cell aggregation (flocculation) is crucial for developing functional 3D cell cultures.
• Surface modification of CNFs can alter their interactions with cells.

Purpose of the Study:

• To investigate the impact of surface charge on concentrated polymer brush (CPB)-grafted CNFs on HepG2 cell flocculation.
• To explore the relationship between surface charge, ζ-potential, and cell floc size.
• To establish a novel 3D cell culture system driven by colloidal flocculation theory.

Main Methods:

• Grafting four different polyelectrolytes (PSSNa, PAA, PDMAEMA, PMTAC) onto CNF surfaces using surface-initiated atom transfer radical polymerization to create CNF-CPBs.
• Characterizing the surface charge and ζ-potential of the modified CNFs.
• Analyzing HepG2 cell floc size in relation to CNF-CPB surface properties.

Main Results:

• HepG2 cell floc size was significantly influenced by the surface charge of CNF-CPBs.
• Anionic CNF-CPBs (CNF-PSSNa, CNF-PAA) showed varying floc sizes, with CNF-PSSNa forming larger flocs.
• Lower ζ-potential values correlated with smaller floc sizes due to electrostatic repulsion.
• Cytotoxic cationic CNF-CPBs (CNF-PDMAEMA, CNF-PMTAC) limited floc size growth.

Conclusions:

• Appropriate electrostatic interactions between CNF-CPBs and HepG2 cells are essential for controlled floc formation.
• The study demonstrates the applicability of colloidal flocculation theory in a novel 3D cell culture system.
• Surface charge engineering of biomaterials is a critical factor for optimizing 3D cell culture systems and cell function.