This lecture by the instructor covers various aspects of flexible bioelectronics, focusing on thin films on substrates. Topics include impedance matching for electrodes, capacitor-coupled current stimulation, multilayered device structures, stress-strain responses of electronic materials, critical strain considerations, bending stiffness, and the influence of substrate properties on film behavior. The lecture also discusses strategies to minimize strain in film-substrate stacks and the importance of placing devices in the neutral plane for optimal performance.