Dual-potential electrochemiluminescence from black phosphorus and graphitic carbon nitrides for label-free enzymatic biosensing

Simultaneous anodic and cathodic electrochemiluminescence (ECL) emissions of black phosphorus nanosheets (BPNSs) and graphitic carbon nitrides (g-C3N4) were reported based on the co-existence of different co-reactants. Anodic ECL was obtained at the BPNSs modified electrode with tripropylamine (TPrA) as a co-reactant, while g-C3N4 was selected as another emitter to obtain cathodic ECL emission with K2S2O8 as co-reactant. Employing the superiority of two separate ECL systems, a facile ECL method was developed for cholesterol detection based on cholesterol oxidase (ChOx) immobilized g-C(3)N(4/)BPNSs modified glassy carbon electrode (g-C(3)N(4/)BPNSs/GCE). False positive signals can be significantly reduced based on the separation of anode and cathode ECL signals from BPNSs and g-C3N4, respectively. The proposed biosensor provided a quantitative readout proportional to cholesterol concentrations in the range from 0.5 mu M to 0.5 mM with a detection limit of 0.14 mu M (cathodic system, 3 sigma, n = 6) and 0.32 mu M (anodic system, 3 sigma, n = 6). The proposed biosensor demonstrated excellent analytical performance with remarkable sensitivity, manifesting its potential application in enzymatic biosensing field.

Automated summary

Simultaneous anodic and cathodic electrochemiluminescence emissions were achieved using black phosphorus nanosheets and graphitic carbon nitrides as emitters, leading to the development of a biosensor for cholesterol detection. By separating the anode and cathode ECL signals, false positive signals can be significantly reduced, demonstrating excellent analytical performance with remarkable sensitivity and potential for enzymatic biosensing applications.