Fig. 1

Examples of NMs as biocompatible coatings of NIs. 1: (a) Layer-by-layer deposition of chitosan and ulvan multilayers on silicon surfaces. (b) Confocal microscopy (CM) images showing astrocyte preferential adhesion on a poly-D-lysine surface with respect to a multilayer surface. (c) CM images of neurons (red) and astrocytes (green) cocultured on poly-D-lysine and multilayer surfaces. Multilayer surfaces enhance neuron adhesion and reduce astrocyte anchorage (Reproduced and adapted with permission from [Moon et al. 2020] Copyright 2020, ACS Publications). 2: (a) Schematic illustration of amphiphilic siloxane-modified chitosan nanogel patterned on a polyimide-based NI surface. The nanogel is loaded with oligo-proanthocyanidin and provides EMC-mimicking behavior. (b) Photograph and SEM image (c) of the device showing nanogel patterned onto polyimide, exposing electrode active sites (Reproduced and adapted with permission from [Huang et al. 2015] © 2015 John Wiley & Sons, Inc.). 3: (a) Schematic illustration of the EMC-based intracortical electrode in the side view and after laser ablation of the electrode (b). Image of the total device with the electrode tip in the inset (c) (Reproduced and adapted with permission from [Shen et al. 2015] Copyright 2015, Nature.). 4: (a) Schematic illustration of the process of brain tissue adhesion of a cortical electrode array caused by silk supporting layer dissolution. (b) Picture of the same electrode adhering onto a glass hemisphere during silk layer dissolution. (c) Electrode array perfectly adhered to an animal visual cortex during recording activity (left) and the color map of the average evoked response from each electrode (right) showing the rms amplitude of the recorded signal at each electrode active site (Reproduced and adapted with permission from [Kim et al. 2010] Copyright 2010, Nature). 5: (a) Polyimide-based electrode coated with a silk layer on its bottom side, exposing the surface of the recording active sites. (b) Average buckling force levels of uncoated and silk-coated electrodes prepared with 1, 3 and 6 coating steps (Reproduced and adapted with permission from [Tien et al. 2013] © 2013 John Wiley & Sons, Inc.)