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A metabolic biofuel cell: conversion of human leukocyte metabolic activity to electrical currents.

Justin GA, Zhang Y, Cui XT, Bradberry CW, Sun M, Sclabassi RJ - J Biol Eng (2011)

Bottom Line: SCE for the PMA (phorbol ester) activated primary cells, with a notable absence of a reduction peak was observed.HPLC confirmed the release of serotonin (5-HT) from the PMA activated primary cells.It is believed that serotonin, among other biochemical species released by the activated cells, contributes to the observed BFC currents.

View Article: PubMed Central - HTML - PubMed

Affiliation: Computational Diagnostics, Inc, Pittsburgh, PA, USA. bobs@cdi.com.

ABSTRACT
An investigation of the electrochemical activity of human white blood cells (WBC) for biofuel cell (BFC) applications is described. WBCs isolated from whole human blood were suspended in PBS and introduced into the anode compartment of a proton exchange membrane (PEM) fuel cell. The cathode compartment contained a 50 mM potassium ferricyanide solution. Average current densities between 0.9 and 1.6 μA cm-2 and open circuit potentials (Voc) between 83 and 102 mV were obtained, which were both higher than control values. Cyclic voltammetry was used to investigate the electrochemical activity of the activated WBCs in an attempt to elucidate the mechanism of electron transfer between the cells and electrode. Voltammograms were obtained for the WBCs, including peripheral blood mononuclear cells (PBMCs - a lymphocyte-monocyte mixture isolated on a Ficoll gradient), a B lymphoblastoid cell line (BLCL), and two leukemia cell lines, namely K562 and Jurkat. An oxidation peak at about 363 mV vs. SCE for the PMA (phorbol ester) activated primary cells, with a notable absence of a reduction peak was observed. Oxidation peaks were not observed for the BLCL, K562 or Jurkat cell lines. HPLC confirmed the release of serotonin (5-HT) from the PMA activated primary cells. It is believed that serotonin, among other biochemical species released by the activated cells, contributes to the observed BFC currents.

No MeSH data available.


Related in: MedlinePlus

Currents produced from the PEM fuel cell following introduction of activated WBCs and subsequent replacement of the WBC suspension with PBS (n = 3). A significant decrease in the current output occurs, indicating that the WBC suspension is the primary contributor to the observed currents (p < 0.05).
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Figure 3: Currents produced from the PEM fuel cell following introduction of activated WBCs and subsequent replacement of the WBC suspension with PBS (n = 3). A significant decrease in the current output occurs, indicating that the WBC suspension is the primary contributor to the observed currents (p < 0.05).

Mentions: Average current densities between 0.9 and 1.6 μA cm-2 (n = 3) and average open circuit potentials between 83 and 102 mV (n = 3) were measured when a proton exchange membrane (PEM) fuel cell (PEMFC) containing WBCs isolated by RBC lysis was placed in series with a 100 Ω resistor (Figure 3). There was significant variation in the observed currents, with standard deviations reaching as high +/- 61%. Over time; however the standard deviations of the current density values across the three WBC samples declined appreciably suggesting that the system was gradually achieving stability. On replacing the WBC suspension with a solution of the activating agents (PMA and ionomycin) dissolved in PBS, a decrease in the current density was observed compared to the WBC suspension. In the case of this control, a similar phenomenon was observed where the standard deviation obtained from the three separate experiments decreased over time. Again, this was attributed to the attainment of stability within the system. The observation of small currents for the control is an indication that the PMA and/or ionomycin have some electrochemical activity. However, the results illustrated in Figure 3 suggest that the white blood cells are also transferring electrons to the electrode surface, contributing to the higher magnitude currents. The production of metabolic products by the cells can be implicated, just as bacterial cells in microbial fuel cells have been shown to produce soluble metabolic products that are oxidized at the fuel cell anode. A one-tailed student's t-test of the experimental and control data reveal a p value less than 0.05 (p = 1.1 × 10-6) indicating that the current densities recorded are significantly different.


A metabolic biofuel cell: conversion of human leukocyte metabolic activity to electrical currents.

Justin GA, Zhang Y, Cui XT, Bradberry CW, Sun M, Sclabassi RJ - J Biol Eng (2011)

Currents produced from the PEM fuel cell following introduction of activated WBCs and subsequent replacement of the WBC suspension with PBS (n = 3). A significant decrease in the current output occurs, indicating that the WBC suspension is the primary contributor to the observed currents (p < 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3113927&req=5

Figure 3: Currents produced from the PEM fuel cell following introduction of activated WBCs and subsequent replacement of the WBC suspension with PBS (n = 3). A significant decrease in the current output occurs, indicating that the WBC suspension is the primary contributor to the observed currents (p < 0.05).
Mentions: Average current densities between 0.9 and 1.6 μA cm-2 (n = 3) and average open circuit potentials between 83 and 102 mV (n = 3) were measured when a proton exchange membrane (PEM) fuel cell (PEMFC) containing WBCs isolated by RBC lysis was placed in series with a 100 Ω resistor (Figure 3). There was significant variation in the observed currents, with standard deviations reaching as high +/- 61%. Over time; however the standard deviations of the current density values across the three WBC samples declined appreciably suggesting that the system was gradually achieving stability. On replacing the WBC suspension with a solution of the activating agents (PMA and ionomycin) dissolved in PBS, a decrease in the current density was observed compared to the WBC suspension. In the case of this control, a similar phenomenon was observed where the standard deviation obtained from the three separate experiments decreased over time. Again, this was attributed to the attainment of stability within the system. The observation of small currents for the control is an indication that the PMA and/or ionomycin have some electrochemical activity. However, the results illustrated in Figure 3 suggest that the white blood cells are also transferring electrons to the electrode surface, contributing to the higher magnitude currents. The production of metabolic products by the cells can be implicated, just as bacterial cells in microbial fuel cells have been shown to produce soluble metabolic products that are oxidized at the fuel cell anode. A one-tailed student's t-test of the experimental and control data reveal a p value less than 0.05 (p = 1.1 × 10-6) indicating that the current densities recorded are significantly different.

Bottom Line: SCE for the PMA (phorbol ester) activated primary cells, with a notable absence of a reduction peak was observed.HPLC confirmed the release of serotonin (5-HT) from the PMA activated primary cells.It is believed that serotonin, among other biochemical species released by the activated cells, contributes to the observed BFC currents.

View Article: PubMed Central - HTML - PubMed

Affiliation: Computational Diagnostics, Inc, Pittsburgh, PA, USA. bobs@cdi.com.

ABSTRACT
An investigation of the electrochemical activity of human white blood cells (WBC) for biofuel cell (BFC) applications is described. WBCs isolated from whole human blood were suspended in PBS and introduced into the anode compartment of a proton exchange membrane (PEM) fuel cell. The cathode compartment contained a 50 mM potassium ferricyanide solution. Average current densities between 0.9 and 1.6 μA cm-2 and open circuit potentials (Voc) between 83 and 102 mV were obtained, which were both higher than control values. Cyclic voltammetry was used to investigate the electrochemical activity of the activated WBCs in an attempt to elucidate the mechanism of electron transfer between the cells and electrode. Voltammograms were obtained for the WBCs, including peripheral blood mononuclear cells (PBMCs - a lymphocyte-monocyte mixture isolated on a Ficoll gradient), a B lymphoblastoid cell line (BLCL), and two leukemia cell lines, namely K562 and Jurkat. An oxidation peak at about 363 mV vs. SCE for the PMA (phorbol ester) activated primary cells, with a notable absence of a reduction peak was observed. Oxidation peaks were not observed for the BLCL, K562 or Jurkat cell lines. HPLC confirmed the release of serotonin (5-HT) from the PMA activated primary cells. It is believed that serotonin, among other biochemical species released by the activated cells, contributes to the observed BFC currents.

No MeSH data available.


Related in: MedlinePlus