Wafer-Scale Dendritic Nanoporous Platinum Films for Neural Electrodes

Two-dimensional (2D) metallic nanosheets are promising for neural implants, but their application is hindered by limited lateral dimensions, poor mechanical compliance, and insufficient electrochemical stability. Here, we report a wafer-scale wet-chemical synthesis of an ultrathin, intrinsically porous dendritic platinum (Pt) film (den-2DPt_waf) that can be transferred onto flexible substrates for robust neural interfacing. Confined Pt growth on a layered double hydroxide (LDH)-modified Si wafer produces a wafer-sized, 6-nm-thick film that is vertically conductive but laterally insulating. As a bioelectrode (area = 4 × 10^-4 cm²), den-2DPt_waf exhibits low impedance (∼45 Ω at 1 kHz), high charge storage capacity (∼12 mC cm^-2), and high charge injection capacity (1.13 mC cm^-2). It also maintains its performance after >10,000 bending cycles at a 2-mm radius and under accelerated oxidative conditions (3% H₂O₂), outperforming conventional flat Pt films. In vivo, den-2DPt_waf electrodes enable effective vagus nerve stimulation, inducing immediate, current-dependent reductions in rat breathing rate while maintaining stable activation thresholds and electrochemical and structural integrity over two weeks. This scalable porous Pt film provides a mechanically compliant and electrochemically resilient platform for long-term neural recording and stimulation.