A biofunctionalization scheme for neural interfaces using polydopamine polymer

Chemical surface modification of neuron-surface interfaces is essential for the development of biologically active and functional neural interfaces. Different types of surface modification schemes are required to derivatize either electrode or insulator surfaces, which limits the surface chemistry based neural interface design. Herein, we report a novel and powerful approach for modifying neuron-surface interfaces using mussel-inspired polymer ('polydopamine film(polyDA)') for generating effective chemical platforms on both electrode and insulator surfaces simultaneously. We applied polyDAs to common neural interface surfaces (gold, glass, platinum, indium tin oxide, liquid crystal polymer) and subsequently functionalized them by covalently linking biomolecules. The surfaces coated with polyDAs exhibited uniform and reproducible surface properties and they all became neuron-adhesive after linking with poly-D-lysine. In addition, polydopamine-coated microelectrode arrays were readily functional such that spontaneous and evoked neural activities could be recorded from cultured neuronal networks. We have successfully showed that a novel polyDA can be effectively used for the neural interface design.