A strategy of materials synthesis, characteristic evaluations, and manufacturing process for a mechanically elastic, biologically safe silicon‐based dopamine detector that is designed to be completely transient, i.e., dissolved in water and/or biofluids, potentially in the brain after a desired period of operation, is introduced. Use of inexpensive, bioresorbable iron (Fe)‐based nanoparticles (NPs) is one of the attractive choices for efficient catalytic oxidation of dopamine as an alternative for noble, nontransient platinum (Pt) nanoparticles, based on extensive studies of synthesized materials and catalytic reactions. Arrays of transient dopamine sensors validate electrochemical functionality to determine physiological levels of dopamine and to selectively sense dopamine in a variety of neurotransmitters, illuminating feasibilities for a higher level of soft, transient electronic implants integrated with other components of overall system. Bioresorbable silicon nanomembranes coated with iron‐containing hybrid nanoparticles for a flexible, transient electrochemical system capable of monitoring physiological levels of dopamine are presented in this article. Results on synthesis of materials, catalytic activity, and manufacturing process highlight the capabilities to apply this technology to biomedical implants. Large‐scale arrays of sensors demonstrate a functional capacity to determine physiological concentrations of dopamine.