**4.2 Surface modification**

The surface properties of materials play a key role in determining their applications. The presence of specific surface chemical functionalities, hydrophilicity, roughness, surface energy, and topography is crucial for biomedical applications of PLA and its interactions with biomacromolecules. Pure PLA causes a mild inflammatory response if it is implanted into human tissues. It is therefore important to design biomaterials with the required surface properties. The different surface modification strategies examined include physical methods, including surface coating, entrapment and plasma treatment, and chemical methods. Both types of approaches are reviewed.
