Layer-by-layer self-assembly of chitosan and poly(γ-glutamic acid) into polyelectrolyte complexes

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Chitosan (Ch) is a biocompatible polysaccharide utilized in various biomedical fields.
• Layer-by-layer (LbL) self-assembly enables the creation of complex multilayered architectures from polycations and polyanions.
• These structures are promising for tissue engineering, drug delivery, and mimicking the extracellular matrix.

Purpose of the Study:

• To create and characterize multilayered films using chitosan (Ch) and microbially produced poly(γ-glutamic acid) (γ-PGA).
• To investigate the electrostatic interactions between Ch and γ-PGA in a layer-by-layer assembly process.
• To evaluate the cytotoxicity of the resulting Ch/γ-PGA polyelectrolyte multilayers (PEMs) for potential biomedical applications.

Main Methods:

• Fabrication of Ch/γ-PGA multilayered films up to six layers using the LbL self-assembly technique.
• Characterization of polymer interactions and film properties using ellipsometry, quartz crystal microbalance with dissipation (QCM-D), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), and zeta potential measurements.
• Cytotoxicity assessment of the Ch/γ-PGA PEMs according to ISO 10993-5 standards.

Main Results:

• Successful formation of Ch/γ-PGA multilayered films through electrostatic interactions.
• Comprehensive characterization revealing the nanostructure and properties of the PEMs.
• Demonstrated lack of cytotoxicity for Ch/γ-PGA PEMs, meeting ISO 10993-5 requirements.

Conclusions:

• Chitosan and poly(γ-glutamic acid) effectively form stable multilayered films via LbL assembly.
• The characterized Ch/γ-PGA PEMs are biocompatible and non-cytotoxic.
• These novel biomaterial surfaces hold promise as substrates for studying cell-biomaterial interactions in tissue regeneration.