Constructing combinational and sequential logic devices through an intelligent electrocatalytic interface with immobilized MoS2 quantum dots and enzymes

• Published in: Talanta (Oxford) 2022-10, Vol.248, p.123615-123615, Article 123615
• Main Authors: Xiao, Ruiqi, Wei, Wenting, Li, Jiaxuan, Xiao, Cong, Yao, Huiqin, Liu, Hongyun
• Format: Article
• Language: English
• Subjects: Biocomputing; D flip flop; Electrocatalysis; Molybdenum disulfide quantum dots; Sequential logic devices
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2022.123615

Stable molybdenum disulfide quantum dots (MoS2 QDs) were synthesized using a simple method and embedded into chitosan (Chit) films with glucose oxidase (GOD) on the surface of a polyaniline (PANI) pre-electrodeposited ITO electrode, designated as Chit-MoS2-GOD/PANI. At the prepared film electrode, the fluorescence property of MoS2 QDs as well as the catalytic properties of MoS2 QDs and GOD were well maintained and could be reversibly regulated by external stimuli, such as pH, potential, and the concentrations of glucose and ascorbic acid (AA) in the solution. By controlling the redox state of PANI with an externally applied voltage, the color of the film electrode switched between violet blue and nearly transparent, simultaneously quenching/dequenching the fluorescence signals from MoS2 QDs through Fӧster resonance energy transfer (FRET). The electrocatalytic signals toward hydrogen peroxide (H2O2), a product formed by biocatalysis between glucose and GOD, could be tuned through the catalytic capacity of MoS2 QDs in the films. Thus, an intelligent platform was built based on the film electrode with pH, potential, glucose and AA as inputs and UV–vis extinction (E), photoluminescent intensity (PL), and amperometric current (I) as outputs. Combinational logic operations such as a 4-input/5-output logic network and sequential logic operations such as a keypad lock and a reprogrammable delay/data (D) flip flop was first simulated in a biocomputing system with the film-modified electrode. This work demonstrated the construction of a multiple stimulus-responsive system with dual-functional nanomaterials and provided a new approach for sequential logic operations for further applications in the information storage. Several combinational and sequential logic devices were preliminary built through a stimulus-responsive biointerface with immobilized MoS2 quantum dots (MoS2 QDs) and glucose oxidase (GOD) in chitosan (Chit) hydrogel films on the surface of polyaniline (PANI) pre-deposited ITO electrode. [Display omitted] •Dual-functional MoS2 QDs were utilized as a “bridge” to design a biocomputing platform.•Both the electrocatalysis and biocatalysis of the film electrode were controllable.•Switchable electrochemical, fluorescence and UV–vis signals were used as outputs.•Preliminary simulation of a D flip flop at a film electrode was first implemented.