Laser Micropatterning of Archival Gold CDs: A Maskless Route to Low‑Cost Microelectrode Arrays and Beyond

Archival gold compact discs provide a nanometrically smooth, clean, and highly conductive thin‐film gold surface—an exceptionally low‐cost alternative to gold‐coated silicon wafers—and thus an unexplored platform for next‐generation microdevices. Here, we introduce this ultra‐low‐cost and nanometrically smooth thin‐film gold platform as a substrate directly patternable using rapid, maskless UV and CO 2 ‐laser micropatterning. This single‐step approach produces high‐fidelity microelectrode arrays and bipolar electrodes with ∼20 µm resolution—without photoresists, chemical etchants, or photolithography. The devices exhibit superior electrochemical performance, including enhanced current densities and stable steady‐state behavior, and are immediately applicable to cyclic voltammetry and electrochemiluminescence sensing. By transforming discarded CDs into high‐performance microscale architectures, this work establishes a sustainable, scalable platform for next‐generation biosensing, microfluidics integration, and low‐barrier materials prototyping.