Bioinspired pH-Sensitive Surface on Bioinert Substrate.

Area of Science:

• Biomaterials Science
• Surface Chemistry
• Cell Biology

Background:

• Polydimethylsiloxane (PDMS) is a widely used biomaterial known for its excellent properties but limited by inherent hydrophobicity, which hinders cell growth and differentiation.
• PDMS's intrinsic inertness restricts its use in applications requiring responsive materials.
• Dopamine's ability to adhere to diverse surfaces via noncovalent and covalent interactions offers a pathway for surface modification.

Purpose of the Study:

• To transform bioinert PDMS into a bioactive and pH-sensitive material using polydopamine (PDA).
• To investigate the impact of PDA modification on PDMS surface properties, including hydrophobicity and cell interaction.
• To evaluate the cytocompatibility and responsiveness of PDA-modified PDMS for potential biomedical applications.

Main Methods:

• Surface modification of PDMS with biocompatible and pH-sensitive polydopamine (PDA).
• Characterization of PDA-PDMS binding using scanning electron microscopy (SEM) and atomic force microscopy (AFM).
• Assessment of surface properties (contact angle, friction) and protein adsorption, along with cell adhesion, proliferation, and spreading assays.

Main Results:

• PDA modification significantly reduced the contact angle of PDMS, indicating increased hydrophilicity.
• PDA-modified PDMS exhibited pH-sensitive behavior, confirmed by contact angle, friction, and protein adsorption tests.
• PDA modification substantially enhanced cell adhesion, proliferation, and spreading compared to unmodified PDMS surfaces.

Conclusions:

• The cytocompatibility of PDA-modified PDMS is primarily determined by surface chemical properties rather than surface roughness.
• PDA/PDMS demonstrates pH-sensitive characteristics and effectively promotes cell growth and proliferation.
• This study presents a viable strategy for creating bioactive and responsive PDMS-based materials for advanced biomedical applications.