Electrochemical biomemory device consisting of recombinant protein molecules

Emerging materials for the electrochemical detection of COVID-19

The SARS-CoV-2 virus is still causing a dramatic loss of human lives worldwide, constituting an unprecedented challenge for the society, public health and economy, to overcome. The up-to-date diagnostic tests, PCR, antibody ELISA and Rapid Antigen, require special equipment, hours of analysis and special staff. For this reason, many research groups have focused recently on the design and development of electrochemical biosensors for the SARS-CoV-2 detection, indicating that they can play a significant role in controlling COVID disease. In this review we thoroughly discuss the transducer electrode nanomaterials investigated in order to improve the sensitivity, specificity and response time of the as-developed SARS-CoV-2 electrochemical biosensors. Particularly, we mainly focus on the results appeard on Au-based and carbon or graphene-based electrodes, which are the main material groups recently investigated worldwidely. Additionally, the adopted electrochemical detection techniques are also discussed, highlighting their pros and cos. The nanomaterial-based electrochemical biosensors could enable a fast, accurate and without special cost, virus detection. However, further research is required in terms of new nanomaterials and synthesis strategies in order the SARS-CoV-2 electrochemical biosensors to be commercialized.

Recent Advances in Biomolecule-Nanomaterial Heterolayer-Based Charge Storage Devices for Bioelectronic Applications

With the acceleration of the Fourth Industrial Revolution, the development of information and communications technology requires innovative information storage devices and processing devices with low power and ultrahigh stability. Accordingly, bioelectronic devices have gained considerable attention as a promising alternative to silicon-based devices because of their various applications, including human-body-attached devices, biomaterial-based computation systems, and biomaterial-nanomaterial hybrid-based charge storage devices. Nanomaterial-based charge storage devices have witnessed considerable development owing to their similarity to conventional charge storage devices and their ease of applicability. The introduction of a biomaterial-to-nanomaterial-based system using a combination of biomolecules and nanostructures provides outstanding electrochemical, electrical, and optical properties that can be applied to the fabrication of charge storage devices. Here, we describe the recent advances in charge storage devices containing a biomolecule and nanoparticle heterolayer including (1) electrical resistive charge storage devices, (2) electrochemical biomemory devices, (3) field-effect transistors, and (4) biomemristors. Progress in biomolecule-nanomaterial heterolayer-based charge storage devices will lead to unprecedented opportunities for the integration of information and communications technology, biotechnology, and nanotechnology for the Fourth Industrial Revolution.

Fabrication of Electrochemical-Based Bioelectronic Device and Biosensor Composed of Biomaterial-Nanomaterial Hybrid

The field of bioelectronics has paved the way for the development of biochips, biomedical devices, biosensors and biocomputation devices. Various biosensors and biomedical devices have been developed to commercialize laboratory products and transform them into industry products in the clinical, pharmaceutical, environmental fields. Recently, the electrochemical bioelectronic devices that mimicked the functionality of living organisms in nature were applied to the use of bioelectronics device and biosensors. In particular, the electrochemical-based bioelectronic devices and biosensors composed of biomolecule-nanoparticle hybrids have been proposed to generate new functionality as alternatives to silicon-based electronic computation devices, such as information storage, process, computations and detection. In this chapter, we described the recent progress of bioelectronic devices and biosensors based on biomaterial-nanomaterial hybrid.

Flexible electrochemical glucose biosensor based on GOx/gold/MoS2/gold nanofilm on the polymer electrode

The need for flexible biosensors has increased because of their potential applications for point-of-care diagnosis and wearable biosensors. However, flexible biosensors have low sensitivity due to the flexibility of the electrode, and their fabrication involves complex processes. To overcome these limitations, a flexible electrochemical enzyme biosensor was developed in this study by immobilizing an enzyme on the flexible polymer electrode modified with a gold/MoS₂/gold nanofilm. The fabrication process involved sputter deposition of gold, spin coating of MoS₂, and sputter deposition of gold on the flexible polymer electrode (commercially available Kapton^® polyimide film). The flexible glucose biosensor was made by immobilization of glucose oxidase on a flexible electrode by using a chemical linker. The detection limit for glucose was estimated to be 10 nM, which indicates more sensitivity as compared with a previously reported flexible glucose sensor. This sensitivity is due to the facilitation of electron transfer by MoS₂. The flexure extension of this biosensor was estimated at 3.48 mm, which is much higher than that of the rigid sensor using a gold-coated silicon electrode (0.09 mm), according to measurements with a micro-fatigue tester. The proposed flexible biosensor composed of the enzyme/gold/MoS₂/gold nanofilm on the polymer electrode can be used as a flexible sensing platform for developing wearable biosensing systems because of its high sensitivity, high flexibility, and simple fabrication process.

A biomemory chip composed of a myoglobin/CNT heterolayer fabricated by the protein-adsorption-precipitation-crosslinking (PAPC) technique

In this study, a biomemory chip consisting of a myoglobin/carbon nanotube (CNT) heterolayer is fabricated via the protein-adsorption-precipitation-crosslinking (PAPC) technique for electrochemical signal enhancement, long-term stability, and improved memory function. The PAPC technique is used to fabricate a myoglobin/CNT heterolayer with a CNT core and a high-density myoglobin-shell structure to achieve efficient heterolayer formation and improved performance of the heterolayer. The fabricated myoglobin/CNT heterolayer is immobilized onto a Au substrate through a chemical linker. The surface morphology of the deposited heterolayer is investigated via transmission electron microscopy and atomic force microscopy. The redox properties of the myoglobin/CNT heterolayer are investigated by cyclic voltammetry, and the memory function of the heterolayer, including the "write step" and "erase step," is measured by chronoamperometry. Compared with the myoglobin monolayer without CNT, the myoglobin/CNT heterolayer fabricated by the PAPC technique exhibits greater electrochemical signal enhancement, long-term stability at room temperature, and improved memory function. The results suggest that the proposed myoglobin/CNT heterolayer produced via the PAPC technique can be applied as a platform for bioelectronic devices to achieve improved signal intensity and durability.