Solid-State Laser-Assisted Synthesis of Cobalt Single-Atom Catalysts for Detecting Superoxide Radical Anions

Cobalt single-atom nanozymes (CoSAN) are demonstrated as excellent nanomaterials for a wide range of electrochemical applications. Traditional solution-based synthesis of CoSAN faces challenges such as multiple steps, extensive washings, and high-temperature annealing. To address these issues, we introduce a single-step solid-state synthesis using laser technology. This approach facilitates atomic dispersion of cobalt while concurrently generating laser-scribed graphene (LSG) nanosheets. The presence of Co atoms on the LSG surface is confirmed by using high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and inductively coupled plasma-optical emission spectroscopy (ICP-OES). The resulting CoSAN electrode exhibits excellent electrocatalytic sensing performance to superoxide anions (O2•–), providing rapid electron transfer and excellent signal amplification. Elevated levels of O2•– serve as indicators of oxidative stress, which is associated with several chronic diseases. The CoSAN sensor achieves high sensitivity and low detection limits for the electrochemical determination of O2•– in lab samples, human serum samples, and neuroblastoma cells. The straightforward synthesis method and outstanding electrochemical sensing properties of CoSAN suggest significant potential for biomedical diagnostic applications.