Electrochemical redox signaling of hemoglobin in human whole blood and its relevance to anemia and thalassemia diagnosis

Abstract

A highly redox active human whole blood-carbon nanomaterial modified electrode has been developed, which showed a redox peak (vs. Ag/AgCl) similar to that of hemoglobin (vs. Ag/AgCl) in red blood cells. Clinical relevance of this for direct electrochemical analysis of blood hemoglobin content (anemia) and thalassemia disease diagnosis was demonstrated.

Electrochemical Red Blood Cell Counting: One at a Time

“…The enhancement of the oxygen reduction currents is a result of excess oxygen inside the cell. This is consistent with previous results that demonstrated direct oxygen reduction using other electrodes modified with RBC or complete blood . Here, we show that this is true for solutions containing high RBC concentrations as well.…”

“…We first investigated the electrochemical response arising from RBC immobilized on an edge‐plane pyrolytic graphite (EPPG, R =1.5 mm) serving as a working electrode. EPPG is compatible with biological molecules thus eliminating complexity from additional supporting materials such as nafion, or graphitized mesoporous carbon . Specifically, facile electron transfer of the FeIII/FeII redox couple of haemoglobin on EPPG was demonstrated by Toh at el .…”

Soft Probes for Bio-electrochemical Imaging

“…[226] The E°for the FcMeOH/FcMeOH + redox couple in PBS buffer, pH 7 is around 0.44 V vs. SHE (~0.241 V vs. Ag/AgCl), [227] and E° for heme-Fe(III/II) inside Hb is around -0.37 V vs. Ag/AgCl in blood, pH 7. [228] Thus, the reaction (Fig.5.12a) and [Ru(NH3)6] 3+ (Fig.5.12b) containing electrolyte solutions.…”

Electrochemical Red Blood Cell Counting: One at a Time

“…Further, importantly and newly,w ee xploit the catalytic response of RBC towards hydrogen peroxide which is hitherto yet to be explored electrochemically.T he fast response of the cells towards the decomposition of hydrogen peroxide together with the use of as tate-of-the-art nanoimpact technique allowed us to detect the individual cells near am icroelectrode.U sing this technique,s imultaneous information on unknown RBC concentrations can be gained as well as cell activity towards H 2 O 2 .W ef irst investigated the electrochemical response arising from RBC immobilized on an edge-plane pyrolytic graphite (EPPG, R = 1.5 mm) serving as aw orking electrode.E PPG is compatible with biological molecules [11] thus eliminating complexity from additional supporting materials such as nafion, [7,8] or graphitized mesoporous carbon. [12] Specifically,f acile electron transfer of the FeIII/FeII redox couple of haemoglobin on EPPG was demonstrated by Toha te l. [13] In all measurements reported here,ap latinum wire and as aturated calomel electrode (SCE) were used as ac ounter electrode and ar eference electrode,respectively.T omimic aclinical condition environment, a20mm PBS solution at pH 7.4 under no degasification (solution of air atmosphere was present) was used in all measurements (see the Supporting Information for further details). In all experiments,t he 100 %s olution of sheep red blood cells (Patricell) was diluted at least to 25 %inorder to decrease the solution viscosity,a void agglomeration and to obtain ah omogeneous film for drop-cast experiments.T he electrochemical response of various concentrations of sheep red blood cells drop-casted on an EPPG electrode is shown in Figure 1a.The bare electrode showed asmall electrochemical reduction response because of oxygen in solution (black upper curve,[ O 2 ] = 0.25 mm [14] ), in good agreement with the expected theoretical value (see calculations in the Supporting Information, Figure S1).…”

“…This is consistent with previous results that demonstrated direct oxygen reduction using other electrodes modified with RBC or complete blood. [7,8,12,15] Here,w es how that this is true for solutions containing high RBC concentrations as well. TheR BC concentration in the human blood is around 50 % [16] (ca.…”