Limits...
Nanomaterial-based electrochemical sensing of neurological drugs and neurotransmitters.

Sanghavi BJ, Wolfbeis OS, Hirsch T, Swami NS - Mikrochim Acta (2014)

Bottom Line: This results in tremendous gains in terms of sensitivity, selectivity and versatility.We focus on understanding how specific nano-sized modifiers may be applied to influence the electron transfer event to result in gains in sensitivity, selectivity and versatility of the detection system.Figureᅟ

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, VA 22904 USA.

ABSTRACT

Nanomaterial-modified detection systems represent a chief driver towards the adoption of electrochemical methods, since nanomaterials enable functional tunability, ability to self-assemble, and novel electrical, optical and catalytic properties that emerge at this scale. This results in tremendous gains in terms of sensitivity, selectivity and versatility. We review the electrochemical methods and mechanisms that may be applied to the detection of neurological drugs. We focus on understanding how specific nano-sized modifiers may be applied to influence the electron transfer event to result in gains in sensitivity, selectivity and versatility of the detection system. This critical review is structured on the basis of the Anatomical Therapeutic Chemical (ATC) Classification System, specifically ATC Code N (neurotransmitters). Specific sections are dedicated to the widely used electrodes based on the carbon materials, supporting electrolytes, and on electrochemical detection paradigms for neurological drugs and neurotransmitters within the groups referred to as ATC codes N01 to N07. We finally discuss emerging trends and future challenges such as the development of strategies for simultaneous detection of multiple targets with high spatial and temporal resolutions, the integration of microfluidic strategies for selective and localized analyte pre-concentration, the real-time monitoring of neurotransmitter secretions from active cell cultures under electro- and chemotactic cues, aptamer-based biosensors, and the miniaturization of the sensing system for detection in small sample volumes and for enabling cost savings due to manufacturing scale-up. The Electronic Supporting Material (ESM) includes review articles dealing with the review topic in last 40 years, as well as key properties of the analytes, viz., pKa values, half-life of drugs and their electrochemical mechanisms. The ESM also defines analytical figures of merit of the drugs and neurotransmitters. The article contains 198 references in the main manuscript and 207 references in the Electronic Supporting Material. Figureᅟ

No MeSH data available.


(α) CV obtained for the (A) blank (pH 7.0 phosphate buffer) and (B) acetaminophen: (a) bare GCE, (b) MWCNT and (c) P4VP/MWCNT GCE in 0.1 M phosphate buffer (pH 7.0) with a scan rate 20 mVs−1 [74]. (β) Dopamine detection in vivo at an epoxy-insulated microelectrode. (A) CVs depicting stimulated dopamine release detected from an Armstrong epoxy-insulated CFME placed in the caudate putamen with a stimulation pulse train of 60, 24, 12, and 4 pulses, respectively. (B) The associated current vs. concentration plots. The electrode was scanned from -0.4 to 1.45 V and back at 400 V/s at 10 Hz [31]. (γ) Cyclic voltammograms of phosphate buffer (pH 7.0) at a scan rate of 20 mVs−1 in the presence of morphine at VFc/CPE (a). (b) is as (a) at VFc/MWCNT/CPE. (c) is as (b) and (d) is as (a) at CNT/CPE and at CPE, respectively. (e) is as (a) without mediator. Inset: cyclic voltammogram of VFc/MWCNT/CPE in 0.1 M phosphate buffer (pH 7.0) at a scan rate of 20 mV s−[79]. (δ) Cyclic voltammograms for paracetamol in phosphate buffer of pH 7.5 on MWCNT-BPPGE (dashed line), bare BPPGE (dotted line) and EPPGE (solid line). Scan rate: 100 mVs−1 [71]
© Copyright Policy - OpenAccess
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4281370&req=5

Fig4: (α) CV obtained for the (A) blank (pH 7.0 phosphate buffer) and (B) acetaminophen: (a) bare GCE, (b) MWCNT and (c) P4VP/MWCNT GCE in 0.1 M phosphate buffer (pH 7.0) with a scan rate 20 mVs−1 [74]. (β) Dopamine detection in vivo at an epoxy-insulated microelectrode. (A) CVs depicting stimulated dopamine release detected from an Armstrong epoxy-insulated CFME placed in the caudate putamen with a stimulation pulse train of 60, 24, 12, and 4 pulses, respectively. (B) The associated current vs. concentration plots. The electrode was scanned from -0.4 to 1.45 V and back at 400 V/s at 10 Hz [31]. (γ) Cyclic voltammograms of phosphate buffer (pH 7.0) at a scan rate of 20 mVs−1 in the presence of morphine at VFc/CPE (a). (b) is as (a) at VFc/MWCNT/CPE. (c) is as (b) and (d) is as (a) at CNT/CPE and at CPE, respectively. (e) is as (a) without mediator. Inset: cyclic voltammogram of VFc/MWCNT/CPE in 0.1 M phosphate buffer (pH 7.0) at a scan rate of 20 mV s−[79]. (δ) Cyclic voltammograms for paracetamol in phosphate buffer of pH 7.5 on MWCNT-BPPGE (dashed line), bare BPPGE (dotted line) and EPPGE (solid line). Scan rate: 100 mVs−1 [71]

Mentions: Several articles discuss the employment of MWCNT composite electrodes for analysis of PCT [71–77]. Compton’s group [71] developed a sensitive AdSSWV method for PCT at a MWCNT modified basal planar pyrolytic graphite electrode. As can be seen from the CV plot [Fig. 4δ], the ratio of the faradaic peak current for oxidation and reduction of paracetamol to the background capacitive current is much larger than in case of a bare electrode. This suggests that the adsorption of paracetamol on MWCNTs is much stronger and results in a detection limit of 45 nM. The authors further analyzed PCT in tablets containing paracetamol, aspirin and caffeine, however, a simultaneous determination of these three molecules was not carried out. Also, the size of the electrode is 4.9 mm in diameter, and thus this electrode cannot be used in real time analysis of PCT in cerebral tissues. The effect of pH and scan rates are shown in Fig. 5 and discussed subsequently.Fig. 4


Nanomaterial-based electrochemical sensing of neurological drugs and neurotransmitters.

Sanghavi BJ, Wolfbeis OS, Hirsch T, Swami NS - Mikrochim Acta (2014)

(α) CV obtained for the (A) blank (pH 7.0 phosphate buffer) and (B) acetaminophen: (a) bare GCE, (b) MWCNT and (c) P4VP/MWCNT GCE in 0.1 M phosphate buffer (pH 7.0) with a scan rate 20 mVs−1 [74]. (β) Dopamine detection in vivo at an epoxy-insulated microelectrode. (A) CVs depicting stimulated dopamine release detected from an Armstrong epoxy-insulated CFME placed in the caudate putamen with a stimulation pulse train of 60, 24, 12, and 4 pulses, respectively. (B) The associated current vs. concentration plots. The electrode was scanned from -0.4 to 1.45 V and back at 400 V/s at 10 Hz [31]. (γ) Cyclic voltammograms of phosphate buffer (pH 7.0) at a scan rate of 20 mVs−1 in the presence of morphine at VFc/CPE (a). (b) is as (a) at VFc/MWCNT/CPE. (c) is as (b) and (d) is as (a) at CNT/CPE and at CPE, respectively. (e) is as (a) without mediator. Inset: cyclic voltammogram of VFc/MWCNT/CPE in 0.1 M phosphate buffer (pH 7.0) at a scan rate of 20 mV s−[79]. (δ) Cyclic voltammograms for paracetamol in phosphate buffer of pH 7.5 on MWCNT-BPPGE (dashed line), bare BPPGE (dotted line) and EPPGE (solid line). Scan rate: 100 mVs−1 [71]
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4281370&req=5

Fig4: (α) CV obtained for the (A) blank (pH 7.0 phosphate buffer) and (B) acetaminophen: (a) bare GCE, (b) MWCNT and (c) P4VP/MWCNT GCE in 0.1 M phosphate buffer (pH 7.0) with a scan rate 20 mVs−1 [74]. (β) Dopamine detection in vivo at an epoxy-insulated microelectrode. (A) CVs depicting stimulated dopamine release detected from an Armstrong epoxy-insulated CFME placed in the caudate putamen with a stimulation pulse train of 60, 24, 12, and 4 pulses, respectively. (B) The associated current vs. concentration plots. The electrode was scanned from -0.4 to 1.45 V and back at 400 V/s at 10 Hz [31]. (γ) Cyclic voltammograms of phosphate buffer (pH 7.0) at a scan rate of 20 mVs−1 in the presence of morphine at VFc/CPE (a). (b) is as (a) at VFc/MWCNT/CPE. (c) is as (b) and (d) is as (a) at CNT/CPE and at CPE, respectively. (e) is as (a) without mediator. Inset: cyclic voltammogram of VFc/MWCNT/CPE in 0.1 M phosphate buffer (pH 7.0) at a scan rate of 20 mV s−[79]. (δ) Cyclic voltammograms for paracetamol in phosphate buffer of pH 7.5 on MWCNT-BPPGE (dashed line), bare BPPGE (dotted line) and EPPGE (solid line). Scan rate: 100 mVs−1 [71]
Mentions: Several articles discuss the employment of MWCNT composite electrodes for analysis of PCT [71–77]. Compton’s group [71] developed a sensitive AdSSWV method for PCT at a MWCNT modified basal planar pyrolytic graphite electrode. As can be seen from the CV plot [Fig. 4δ], the ratio of the faradaic peak current for oxidation and reduction of paracetamol to the background capacitive current is much larger than in case of a bare electrode. This suggests that the adsorption of paracetamol on MWCNTs is much stronger and results in a detection limit of 45 nM. The authors further analyzed PCT in tablets containing paracetamol, aspirin and caffeine, however, a simultaneous determination of these three molecules was not carried out. Also, the size of the electrode is 4.9 mm in diameter, and thus this electrode cannot be used in real time analysis of PCT in cerebral tissues. The effect of pH and scan rates are shown in Fig. 5 and discussed subsequently.Fig. 4

Bottom Line: This results in tremendous gains in terms of sensitivity, selectivity and versatility.We focus on understanding how specific nano-sized modifiers may be applied to influence the electron transfer event to result in gains in sensitivity, selectivity and versatility of the detection system.Figureᅟ

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, VA 22904 USA.

ABSTRACT

Nanomaterial-modified detection systems represent a chief driver towards the adoption of electrochemical methods, since nanomaterials enable functional tunability, ability to self-assemble, and novel electrical, optical and catalytic properties that emerge at this scale. This results in tremendous gains in terms of sensitivity, selectivity and versatility. We review the electrochemical methods and mechanisms that may be applied to the detection of neurological drugs. We focus on understanding how specific nano-sized modifiers may be applied to influence the electron transfer event to result in gains in sensitivity, selectivity and versatility of the detection system. This critical review is structured on the basis of the Anatomical Therapeutic Chemical (ATC) Classification System, specifically ATC Code N (neurotransmitters). Specific sections are dedicated to the widely used electrodes based on the carbon materials, supporting electrolytes, and on electrochemical detection paradigms for neurological drugs and neurotransmitters within the groups referred to as ATC codes N01 to N07. We finally discuss emerging trends and future challenges such as the development of strategies for simultaneous detection of multiple targets with high spatial and temporal resolutions, the integration of microfluidic strategies for selective and localized analyte pre-concentration, the real-time monitoring of neurotransmitter secretions from active cell cultures under electro- and chemotactic cues, aptamer-based biosensors, and the miniaturization of the sensing system for detection in small sample volumes and for enabling cost savings due to manufacturing scale-up. The Electronic Supporting Material (ESM) includes review articles dealing with the review topic in last 40 years, as well as key properties of the analytes, viz., pKa values, half-life of drugs and their electrochemical mechanisms. The ESM also defines analytical figures of merit of the drugs and neurotransmitters. The article contains 198 references in the main manuscript and 207 references in the Electronic Supporting Material. Figureᅟ

No MeSH data available.