Wafer‐Scale Dendritic Nanoporous Platinum Films for Neural Electrodes

ABSTRACT 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 cm 2 ), 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% H 2 O 2 ), 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.