Laser-Engineered Ag Nanoparticle on Carbon Cloth Electrodes for Enzyme-Free Electrochemical NAD+ Detection

Nicotinamide adenine dinucleotide ( NAD + ${\rm NAD}^+$ ) is a core redox cofactor, and its concentration reflects age and metabolic state, which has driven the development of NAD + ${\rm NAD}^+$ biochemical analytical techniques. Although electrochemical techniques can rapidly and directly detect NAD + ${\rm NAD}^+$ levels, the translation of laboratory sensors into deployable solutions is often limited by the complexity of electrode interface preparation and batch-to-batch variability. Especially among enzyme-assisted methods, the multi-step biochemical immobilization and activity preservation processes are required. Therefore, developing enzyme-free and scalable NAD + ${\rm NAD}^+$ electroanalytical manufacturing strategies remains important. Here, a rapid two-step laser-induced transfer strategy is proposed to fabricate flexible silver nanoparticle–decorated carbon cloth electrodes (AgNPs@CC) for enzyme-free NAD + ${\rm NAD}^+$ sensing. This strategy reduced interfacial impedance and established a robust cathodic window for enzyme-free NAD + ${\rm NAD}^+$ detection. The electrodes exhibit a linear operating range of 10–300 , an excellent sensitivity (S = −3.16 ) at the low concentration range(10–100 ), and outstanding tolerance to typical interferents (LA, UA, AA, glucose, and NADH) and robust storage stability. This method eliminates the wet-chemical nanoparticle synthesis step and simplifies the production workflow, offering potential for applications like integration into portable sensing platforms.