Polymer brushes allow the surface functionalisation of a wide range of substrates with polymer chains with controlled chemistry, therefore enabling the precise control of physico-chemical properties of corresponding interfaces. Such level of control has clear implications for the design of biomaterials, implants, scaffolds and devices in the biomedical field. For example, this enables the regulation of protein adsorption and the biofunctionalisation of biomaterials to promote cell adhesion, regulate signalling, confer bactericidal properties or targeting of specific cells or tissues. In addition, the temperature- and salt-responsive properties of some polymer brushes enable the capture and controlled release of therapeutics, including for gene delivery applications. Importantly, such control of surface chemistry can be achieved independently of the inherent properties and chemistry of the core substrate, whether it is an implant, scaffold or nanoparticle. Indeed, synthetic approaches to the tethering of polymer brushes are particularly versatile. In this chapter, we review recent progress in the design of polymer brushes in the biomedical field.