Nanofilm of ZnO nanocrystals/carbon nanotubes as biocompatible layer for enzymatic biosensors in capacitive field-effect devices

Hybrid Layer‐by‐Layer Film of Polyelectrolytes‐Embedded Catalytic CoFe2O4 Nanocrystals as Sensing Units in Capacitive Electrolyte‐Insulator‐Semiconductor Devices

“…The potential of this method rises from the variety of types of materials (organic and inorganic) that can be used, as well as, the simple experimental procedure to assemble nanostructured films with synergy among the materials . In particular, the LbL method has been demonstrated to be advantageous for incorporating nanofilms onto EIS sensors, proving to be suitable to study proof‐of‐concept sensing units for biomedical applications . Previous reports have proved that the use of LbL films is beneficial to preserve the enzyme activity, as well as, to enhance the output signal and sensitivity of enzymatic EIS sensors .…”

“…In particular, the LbL method has been demonstrated to be advantageous for incorporating nanofilms onto EIS sensors, proving to be suitable to study proof‐of‐concept sensing units for biomedical applications . Previous reports have proved that the use of LbL films is beneficial to preserve the enzyme activity, as well as, to enhance the output signal and sensitivity of enzymatic EIS sensors . Furthermore, the use of polyelectrolytes in LbL films as sensing membrane have demonstrated to be appropriate for the detection of charged macromolecules …”

“…For instance, LbL films consisting of ZnO nanocrystals dispersed in poly(allylamine hydrochloride) (PAH) and carbon nanotubes (CNTs) exhibited adequate morphological properties for ion permeation and enzyme immobilization over an EIS chip. The incorporation of such a film improved the sensitivity and output signal stability of the EIS sensor toward urea and glucose detection . Other successful applications of LbL films in EIS devices were reported on the use of poly(amidoamine) (PAMAM) dendrimers and CNTs for detection of penicillin G and urea .…”

“…Particularly for the latter, it is reported that compound‐based MFe 2 O 4 (transition metal) presents propitious properties for H 2 O 2 determination due to its spinel structures, as M x+ ions may interact with the O–O bond of H 2 O 2 , releasing ions and electrons that can be measured by using different electrochemical methods . In this sense, the capacitive EIS sensor can be an alternative sensing platform toward H 2 O 2 detection, as the release of H + ‐ions in solution can promote an interface potential across the solid–liquid junction (sensor chip–H 2 O 2 solution), which can be detected by the EIS sensor . However, to our knowledge there are no studies reported involving EIS sensors using CoFe 2 O 4 as sensitive layer for H 2 O 2 detection.…”

Application of ZnO Nanocrystals as a Surface-Enhancer FTIR for Glyphosate Detection

“…Zinc Oxide (ZnO) nanoparticles can be amorphous or crystalline, the difference being that nanocrystals (NCs) are highly stable and do not present genotoxicity, unlike amorphous nanoparticles [ 25 ]. ZnO nanocrystals (NCs) are also used in electronic devices because they have supercapacitor properties [ 26 ].…”