Enhanced Electron Transfer Rates by AC Voltammetry for Ferrocenes Attached to the End of Embedded Carbon Nanofiber Nanoelectrode Arrays

Syed, Lateef U.; Liu, Jianwei; Prior, Allan M.; Hua, Duy H.; Li, Jun

doi:10.1002/elan.201100088

Cited by 11 publications

(18 citation statements)

References 35 publications

(55 reference statements)

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“…Using VACNF NEAs, the optimum frequency for Fc through a short NH 2 CH 2 -linker was found to be 40 times higher than macroscopic glassy carbon electrode (GCE). 17 Similar phenomena were also observed with Fc attached to the electrode surface through a tetrapeptide and linker groups, i.e. H 2 N-(CH 2 ) 4 -CO-Ala-Ala-Asn-LeuNHCH 2 -Fc.…”

Section: Acv Electrochemical Biosensor For Proteasesupporting

confidence: 57%

“…Recently, we found that ACV measurements on CNF NEAs have a distinct advantage over commonly used CV techniques which is based on direct current (DC) ramping. 17 An anomalously high electron transfer rate was obtained with redox-active ferrocene (Fc) molecules attached to the exposed CNF tips of an embedded NEA. 17 This is likely attributed to the unique conically stacked graphitic structure of the CNFs in the NEA.…”

Section: Introductionmentioning

confidence: 99%

“…17 An anomalously high electron transfer rate was obtained with redox-active ferrocene (Fc) molecules attached to the exposed CNF tips of an embedded NEA. 17 This is likely attributed to the unique conically stacked graphitic structure of the CNFs in the NEA. As a result, ACV on CNF NEAs can be carried out at much higher AC frequency (>1 kHz) than that on macroscopic glassy carbon electrodes (GCEs) which is limited at ~75 Hz.…”

Section: Introductionmentioning

confidence: 99%

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Electrochemical enzymatic biosensors using carbon nanofiber nanoelectrode arrays

Swisher

et al. 2012

SPIE Proceedings

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The reduction of electrode size down to nanometers could dramatically enhance detection sensitivity and temporal resolution. Nanoelectrode arrays (NEAs) are of particular interest for ultrasensitive biosensors. Here we report the study of two types of biosensors for measuring enzyme activities using NEAs fabricated with vertically aligned carbon nanofibers (VACNFs). VACNFs of ~100 nm in average diameter and 3-5 μm in length were grown on conductive substrates as uniform vertical arrays which were then encapsulated in SiO 2 matrix leaving only the tips exposed. We demonstrate that such VACNF NEAs can be used in profiling enzyme activities through monitoring the change in electrochemical signals induced by enzymatic reactions to the peptides attached to the VACNF tip. The cleavage of the tetrapeptide with a ferrocene tag by a cancerrelated protease (legumain) was monitored with AC voltammetry. Real-time electrochemical impedance spectroscopy (REIS) was used for fast label-free detection of two reversible processes, i.e. phosphorylation by c-Src tyrosine kinase and dephosphorylation by protein tyrosine phosphatase 1B (PTP1B). The REIS data of phosphorylation were slow and unreliable, but those of dephosphorylation showed large and fast exponential decay due to much higher activity of phosphatase PTP1B. The kinetic data were analyzed with a heterogeneous Michaelis-Menten model to derive the "specificity constant" k cat /K m , which is 8.2x10 3 M -1 s -1 for legumain and (2.1 ± 0.1) x 10 7 M -1 s -1 for phosphatase (PTP1B), well consistent with literature. It is promising to develop VACNF NEA based electrochemical enzymatic biosensors as portable multiplex electronic techniques for rapid cancer diagnosis and treatment monitoring.

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Section: Acv Electrochemical Biosensor For Proteasesupporting

confidence: 57%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Electrochemical enzymatic biosensors using carbon nanofiber nanoelectrode arrays

Swisher

et al. 2012

SPIE Proceedings

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“…15, 16, 22 According to our previous study, the variation can be normalized by using the relative change represented by the “extracted proteolytic signal” S, as defined below: 15 …”

Section: Resultsmentioning

confidence: 99%

“…The unique structure of VACNFs allowed using a high-frequency (∼1 kHz) alternating current voltammetry (ACV) to monitor the small electrochemical signal from Fc. 14-16 In this report, we further apply this technique on detection of cathepsin B activities in four types of cell lysates including normal and breast cancer cells. The cathepsin B activities were found increased from normal to cancer cells and reached highest value in metastatic cancer cell lysate.…”

Section: Introductionmentioning

confidence: 99%

Quantitative electrochemical detection of cathepsin B activity in breast cancer cell lysates using carbon nanofiber nanoelectrode arrays toward identification of cancer formation

Swisher

Prior

Gunaratna

et al. 2015

Nanomedicine: Nanotechnology, Biology and Medicine

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The proteolytic activity of cathepsin B in complex breast cell lysates have been measured with alternating current voltammetry (ACV) using ferrocene (Fc)-labeled-tetrapeptides immobilized on nanoelectrode arrays (NEAs) fabricated with vertically aligned carbon nanofibers (VACNFs). Four types of breast cells have been tested, including normal breast cells (HMEC), transformed breast cells (MCF-10A), breast cancer cells (T47D), and metastatic breast cancer cells (MDA-MB-231). The detected protease activity was found increased in cancer cells, with the MDA-MB-231 metastatic cancer cell lysate showing the highest cathepsin B activity. The equivalent cathepsin B concentration in MDA-MB-231 cancer cell lysate was quantitatively determined by spiking recombinant cathepsin B into the immunoprecipitated MDA-MB-231 lysate and the HMEC whole cell lysate. The results illustrated the potential of this technique as a portable multiplex electronic device for cancer diagnosis and treatment monitoring through rapid profiling the activity of specific cancer-relevant proteases.

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Ferrocene: From the Perspective of Molecular Electronics

Bennett¹,

Long²

2022

Encyclopedia of Inorganic and Bioinorganic Chemistry

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Ferrocene has long been an object of fascination for organometallic chemists. Exhibiting high stability, interesting geometries, and exceptionally well‐defined redox chemistry, ferrocene has been adapted for a wide range of applications that span the breadth of the chemical sciences. This article specifically focuses on reviewing research where ferrocene has been applied in the field of molecular electronics. This begins with a discussion pertaining to the use of ferrocene in the formation of self‐assembled monolayers (SAMs) and their applications in switching, rectification, sensors, and the construction of memory devices. Following this, a brief overview is provided on the lesser developed work performed to elucidate the properties of single ferrocene‐containing molecules. This article provides the reader with an overview of work that has been performed toward the understanding and development of ferrocene‐containing molecular electronic devices.

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Enhanced Electron Transfer Rates by AC Voltammetry for Ferrocenes Attached to the End of Embedded Carbon Nanofiber Nanoelectrode Arrays

Cited by 11 publications

References 35 publications

Electrochemical enzymatic biosensors using carbon nanofiber nanoelectrode arrays

Electrochemical enzymatic biosensors using carbon nanofiber nanoelectrode arrays

Quantitative electrochemical detection of cathepsin B activity in breast cancer cell lysates using carbon nanofiber nanoelectrode arrays toward identification of cancer formation

Ferrocene: From the Perspective of Molecular Electronics

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