Chemiluminescent logic gates based on functionalized gold nanoparticles/graphene oxide nanocomposites

Label-free logic gates (AND, OR, and INHIBIT) based on chemiluminescence (CL) as new optical readout signal have been developed by taking advantage of the unique CL activity of luminol- and lucigenin-functionalized gold nanoparticles/graphene oxide (luminol-lucigenin/AuNPs/GO) nanocomposites. It was found that Fe(2+) ions could induce the CL emission of luminol-lucigenin/AuNPs/GO nanocomposites in alkaline solution. On this basis, by using Fe(2+) ions and NaOH as the inputs and the CL signal as the output, an AND logic gate was fabricated. When the initial reaction system contained luminol-lucigenin/AuNPs/GO nanocomposites and NaOH, either Fe(2+) ions or Ag(+) ions could react with the luminol-lucigenin/AuNPs/GO nanocomposites to produce a strong CL emission. This result was used to design an OR logic gate using Fe(2+) ions and Ag(+) ions as the inputs and CL signal as the output. Moreover, two INHIBIT logic gates for Fe(2+) and Ag(+) were also developed using by NaClO and L-cysteine as their CL inhibitors, respectively. Furthermore, the proposed logic gates were successfully used to detect Fe(2+), Ag(+), and L-cysteine, respectively. The developed logic gates may find future applications in sensing, clinical diagnostics, and environmental monitoring.