- The extent of protein adsorption on a material's surface is primarily influenced by its hydrophobicity.
- Proteins tend to adsorb more readily onto hydrophobic surfaces because these surfaces can disrupt the protein's hydration shell, leading to stronger interactions between the protein and the material.
- This process often results in conformational changes in the adsorbed proteins, which can affect their biological activity.

- While surface charge, surface roughness, and surface energy also play roles in protein adsorption, their effects are generally secondary to hydrophobic interactions.
- For example, surface charge can influence the adsorption of proteins with specific charge distributions but does not control the fundamental driving force for adsorption as strongly as hydrophobicity.
- Similarly, surface roughness can increase the available surface area for adsorption but does not directly affect the protein-material affinity as much as hydrophobicity does.
- Surface energy is related to hydrophobicity but is a more general term, with hydrophobicity providing a more specific insight into the protein-surface interaction.

In summary, hydrophobicity is the most critical characteristic determining the extent of protein adsorption, due to its impact on protein-surface affinity and protein conformation upon binding.

Reference: Ratner, B.D., Hoffman, A.S., Schoen, F.J., Lemons, J.E. Biomaterials Science: An Introduction to Materials in Medicine, 3rd Edition, Chapter 4: Protein-Surface Interactions