Classification of amino acids and oligopeptides with the use of multi-mode chemical images obtained with ion selective electrode array

Electrochemiluminescence sensor based on cyclic peptides-recognition and Au nanoparticles assisted graphitic carbon nitride for glucose determination

A glucose (Glu) sensor was designed by introducing synthetic cyclic peptides (CPs) as recognition receptors and Au nanoparticles assisted graphitic carbon nitride (AuNPs/g-C₃N₄) for electrochemiluminescence (ECL) enhancement. The synthetic CP receptor (cyclo-[-CNDNHCRDNDC-]) with natural active center of Glu binding protein can mimic the interactions between Glu and Glu binding protein to specifically capture Glu. The AuNPs were reduced on g-C₃N₄ and formed a new nanohybrid that can be applied as an ECL emitter. The AuNPs/g-C₃N₄ effectively ameliorated the ECL response of bare g-C₃N₄. The ECL enhancement mechanism was theoretically speculated through computer simulation. Glu quantification was conducted by recording ECL shifts induced by the binding of Glu to CPs. The linear detection range of the fabricated CPs-based ECL sensor was 1 to 100 mmol L^-1, and the detection limit (LOD) was 0.57 nmol L^-1 (S / N = 3). The CP-based ECL sensor also showed good specificity, repeatability, stability, and favorable recoveries in sample analysis. This work offer a promising analytical method for Glu assay in clinical diagnostics and bioprocess monitoring.