Multisensor Systems by Electrochemical Nanowire Assembly for the Analysis of Aqueous Solutions

Abstract

The development of electrochemical multisensor systems is driven by the need for fast, miniature, inexpensive, analytical devices, and advanced interdisciplinary based on both chemometric and (nano)material approaches. A multicomponent analysis of complex mixtures in environmental and technological monitoring, biological samples, and cell culture requires chip-based multisensor systems with high-stability sensors. In this paper, we describe the development, characterization, and applications of chip-based nanoelectrochemical sensor arrays prepared by the directed electrochemical nanowire assembly (DENA) of noble metals and metal alloys to analyze aqueous solutions. A synergic action of the electrode transducer function and electrocatalytic activity of the nanostructured surface toward analytes is achieved in the assembled metal nanowire (NW) sensors. Various sensor nanomaterials (Pd, Ni, Au, and their multicomponent compositions) can be electrochemically assembled on a single chip without employing multiple cycles of photolithography process to realize multi-analyte sensing applications as well as spatial resolution of sensor analysis by this single-chip multisensor system. For multi-analyte electrochemical sensing, individual amperometric signals of two or more nanowires can be acquired, making use of the specific electrocatalytic surface properties of the individual nanowire sensors of the array toward analytes. To demonstrate the application of a new electrochemical multisensor platform, Pd-Au, Pd-Ni, Pd, and Au NW electrode arrays on a single chip were employed for the non-enzymatic analysis of hydrogen peroxide, glucose, and ethanol. The analytes are determined at low absolute values of the detection potentials with linear concentration ranges of 1.0 × 10−6 − 1.0 × 10−3 M (H2O2), 1.5 × 10−7 − 2.0 × 10−3 M (glucose), and 0.7 × 10−3 − 3.0 × 10−2 M (ethanol), detection limits of 2 × 10−7 M (H2O2), 4 × 10−8 M (glucose), and 5.2 × 10−4 M (ethanol), and sensitivities of 18 μA M−1 (H2O2), 178 μA M−1 (glucose), and 28 μA M−1 (ethanol), respectively. The sensors demonstrate a high level of stability due to the non-enzymatic detection mode. Based on the DENA-assembled nanowire electrodes of a compositional diversity, we propose a novel single-chip electrochemical multisensor platform, which is promising for acquiring complex analytical signals for advanced data processing with chemometric techniques aimed at the development of electronic tongue-type multisensor systems for flexible multi-analyte monitoring and healthcare applications.

Applications of Graphene Quantum Dots in Biomedical Sensors

“…Additionally, they are often used for signal amplification by serving as nanocarriers including electron transfer promoters, nanozymes, detector bioreceptors, electroactive labeling elements, and catalysts [34][35][36][37], hence offering novel strategies for biosensing platforms and their practical applicability. Over the last decade, numerous nanomaterials have been continuously studied and employed as signal-amplifying species such as nanoparticles (NPs) [38][39][40], graphene [41][42][43], nanowires [44], carbon nanotubes (CNTs) [45], magnetic beads [46,47] and quantum dots (QDs) [48,49]. Among these nanomaterials, QDs such as graphene quantum dots (GQDs) and carbon dots (CDs) are becoming quite well-known for their multifarious properties such as signal amplifying characteristics, good biocompatibility, tunable size, electro-catalytic performance as well as their capacity for the concurrent and multiple detection of biomolecules.…”

Multisensor Systems and Arrays for Medical Applications Employing Naturally-Occurring Compounds and Materials

“…One of the most common materials is carbon and its allotropes (graphite, glassy carbon), composites and nanomaterials (carbon nanotubes, graphene) [ 1 , 42 ]. Non-conducting materials and flexible polymers, covered with conducting films are also used as sensor substrates for producing the miniaturized electrode arrays [ 1 , 9 , 43 , 44 , 45 , 46 , 47 ]. Natural fibers (cotton, silk, cellulose ( Section 2.3.1 )) can be modified with conducting polymers to form composites, used as electrode materials, with exceptional electric properties [ 48 ].…”

“…Thus, it is often applied when either non-metallic or metallic substrates, modified with specific materials (e.g., gold, modified with sulphur containing non-conducting compounds or proteins) are used. In most of cases, some conducting nanomaterials are used to increase the electroactive area, such as metal (typically noble) nanoparticles [ 1 , 43 , 49 , 50 , 51 , 52 ], carbon nanomaterials (nanoparticles of boron-doped diamond, carbon nanotubes, graphene) [ 43 , 53 , 54 , 55 ], other non-metallic nanoparticles [ 56 ]. Usually, the use of carbon nanotubes and graphene in e-noses and MSA is reported [ 54 , 55 ].…”

“…Although redox mediation is well known, in recent years, several new types such mediators were designed and studied [ 62 , 63 ]. As stated above, mediators are also used in MSAs and MSSs [ 43 , 59 , 64 ].…”

Graphene Quantum Dot-Based Electrochemical Immunosensors for Biomedical Applications

“…To date, plenty of nanomaterials have been investigated as signaling species, including nanoparticles (NPs) [35][36][37], nanowires [38], carbon nanotubes (CNTs) [39], graphene [40][41][42], magnetic beads [43,44], and quantum dots (QDs) [45,46], to further improve the sensitivity, selectivity, and reproducibility of electrochemical immunosensors. Among these materials, QDs, like carbon dots and graphene quantum dots (GQDs), have gained popularity for their unique characteristics such as good biocompatibility, electro-catalytic activity, controllable size, good signal amplification, and multiplexed detection ability.…”