Interfacial Nanoengineering of Hydrogel Surfaces via Block Copolymer Self-Assembly

Area of Science:

• Materials Science
• Polymer Chemistry
• Surface Science

Background:

• Synthetic polymer hydrogels are crucial for various biomedical applications, including drug delivery and soft implants.
• Hydrogel bulk properties are well-studied, but interfacial characteristics significantly impact performance and are often overlooked.
• Existing methods for modifying hydrogel interfaces, such as
• grafting-from
• approaches, can be complex and cumbersome.

Purpose of the Study:

• To develop a straightforward and versatile method for nanoscale modification of hydrogel-water interfaces.
• To demonstrate the efficacy of a
• grafting-to
• strategy using functional block copolymers for surface functionalization.
• To investigate the impact of interfacial modification on hydrogel properties and performance.

Main Methods:

• Utilized a
• grafting-to
• strategy with photoreactive block copolymers for UV-immobilization onto hydrogel substrates.
• Applied the technique to various hydrogel types, including poly(hydroxypropyl acrylate), poly(N-isopropylacrylamide), and alginate gels.
• Characterized the modified interfaces using X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS).

Main Results:

• Successfully achieved nanoscale modification of hydrogel interfaces with polymer brushes, even on low solid content hydrogels (<30 wt %).
• Demonstrated a homogeneous bilayered architecture at the modified interface.
• Showcased precise control over grafting density and demonstrated versatility across different hydrogel types.
• Observed enhanced protein adsorption and improved cell adhesion on modified hydrogels.
• Showed impaired diffusive uptake of small molecules into the bulk hydrogels after surface modification.

Conclusions:

• The developed
• grafting-to
• technique provides an effective and broadly applicable method for interfacial nanoengineering of synthetic polymer hydrogels.
• Tailoring hydrogel interfaces can significantly enhance performance for diverse applications, from biomaterials to drug delivery systems.
• This approach offers a simpler alternative to existing surface modification techniques, enabling precise control over interfacial properties.