Refine
Year of publication
Document Type
- Article (20)
- Book (1)
- Conference Proceeding (1)
Keywords
- Raman spectroscopy (2)
- biosensors (2)
- capacitive field-effect sensors (2)
- Bacillus atrophaeus spores (1)
- DPA (dipicolinic acid) (1)
- acetoin (1)
- acetoin reductase (1)
- alcoholic beverages (1)
- atomic layer deposition (1)
- biocompatible materials (1)
- biodegradable electronic devices (1)
- capacitive electrolyte–insulator–semiconductor sensors (1)
- carbon electrodes (1)
- glucose (1)
- graphene oxide (1)
- hydrogen peroxide (1)
- layer-by-layer technique (1)
- nanomaterials (1)
- optical sensor setup (1)
- optical spore trapping (1)
The ideal combination among biomolecules and nanomaterials is the key for reaching biosensing units with high sensitivity. The challenge, however, is to find out a stable and sensitive film architecture that can be incorporated on the sensor’s surface. In this paper, we report on the benefits of incorporating a layer-by-layer (LbL) nanofilm of polyamidoamine (PAMAM) dendrimer and carbon nanotubes (CNTs) on capacitive electrolyte-insulator-semiconductor (EIS) field-effect sensors for detecting urea. Three sensor arrangements were studied in order to investigate the adequate film architecture, involving the LbL film with the enzyme urease: (i) urease immobilized directly onto a bare EIS [EIS-urease] sensor; (ii) urease atop the LbL film over the EIS [EIS-(PAMAM/CNT)-urease] sensor; and (iii) urease sandwiched between the LbL film and another CNT layer [EIS-(PAMAM/CNT)-urease-CNT]. The surface morphology of all three urea-based EIS biosensors was investigated by atomic force microscopy (AFM), while the biosensing abilities were studied by means of capacitance–voltage (C/V) and dynamic constant-capacitance (ConCap) measureaments at urea concentrations ranging from 0.1 mM to 100 mM. The EIS-urease and EIS-(PAMAM/CNT)-urease sensors showed similar sensitivity (∼18 mV/decade) and a nonregular signal behavior as the urea concentration increased. On the other hand, the EIS-(PAMAM/CNT)-urease-CNT sensor exhibited a superior output signal performance and higher sensitivity of about 33 mV/decade. The presence of the additional CNT layer was decisive to achieve a urea based EIS sensor with enhanced properties. Such sensitive architecture demonstrates that the incorporation of an adequate hybrid enzyme-nanofilm as sensing unit opens new prospects for biosensing applications using the field-effect sensor platform.