Modified Indium Tin Oxide Research Articles

Photoelectrochemical Biosensor Based on Co3O4 Nanoenzyme Coupled with PbS Quantum Dots for Hydrogen Peroxide Detection

A novel kind of hydrogen peroxide (H2O2) photoelectrochemical (PEC) sensor was constructed based on Co3O4 and PbS nanomaterial modified indium tin oxide (ITO) photoelectrode. The Co3O4 nanoparticle...

Effect of Concentration and pH of PBS to the Electrocatalytic Performance of Enzymatic Glucose Biosensor

Phosphate buffer saline (PBS) is commonly applied as an electrolyte for glucose sensor application because ion concentration and osmolality of PBS are similar to the human body. Therefore, it is important to study the effect of concentration and pH of PBS to the electrocatalytic performance of the modified electrode in glucose detection. In this study, the modification of indium tin oxide (ITO) glass electrode by utilizing iron oxide nanoparticles (IONP) coated with citric acid (CA), glucose oxidase (GOx) enzyme and Nafion layer (Nafion/Gox/IONP-CA/ITO) were performed. IONP was prepared by using the precipitation technique through formation of colloidal stable IONP in water at physiological pH. The size of IONP-CA precipitates was ~19 nm with maghemite (γ-Fe2O3) phase characterized using transmission electron microscopy (TEM) and X-ray diffraction (XRD), respectively. Increasing the PBS concentration increased the electrocatalytic performance of the bioelectrode whereas pH of PBS buffer solution affected the GOx bioactivity. The modified electrode Nafion/Gox/IONP-CA/ITO displayed good electrochemical and electrocatalytic performance in glucose detection.

Effect of Hydrazine on Formation of Bismuth Nanoparticles and its Properties as Pb Sensors

Bismuth nanoparticles (BiNPs) are of interest in many applications such as imaging, antimicrobial agent, biosensors and electrochemical electrodes. However, synthesis of pure bismuth is difficult as bismuth tend to oxidise and form bismuth oxide that affects its properties. In this work, BiNPs were synthesised using hydrothermal method in an autoclave at 160°C. The effect of hydrazine (N2H4•H2O) volume as reducing and capping agent was studied from 1.0-2.5ml with 3.6 Bi(NO3)3: 4.2 Polysodium 4-Styrene-Sulfonate: 50 H2O (mass ratio). The produced BiNPs was used to modify indium tin oxide (ITO) substrates and tested as electrochemical heavy metal sensors to detect Pb and As. Pure BiNPs were successfully produced in all hydrazine volume. However, size and crystallinity of BiNPs were influenced by volume of hydrazine. Among these changeable compositions, the mass ratio of Bi(NO3)3 to N2H4•H2O is the most important factor to form uniform size and shape of BiNPs. The addition of the reducing agent, N2H4•H2O into the precursor solution promoted the subsequent reduction of Bi(III) and enabled the growth of BiNPs. Cyclic voltammetry (CV) in 0.002 mol/L of K3Fe(CN)6 electrolyte showed peak current responses obtained for BiNPs/ITO modified electrodes are larger than the bare ITO electrode, which were attributed to the fact that the electrochemical activities of ITO electrode increased by BiNPs surface modification. Stripping current responses of the Differential Pulse Anodic Stripping Voltammetry measurements were recorded for the determination of Pb(II) after a 300 seconds of deposition time at −1.2 V in 0.002 mol/L of acetate buffer solution with pH 4.5. Sensitivity response for the detection of Pb(II) was achieved in the range from 2.5 to 100 μg/L. The limit of detection (LOD) is 2.5 μg/L for Pb(II).

Z-scheme Ag2O/Ag/amorphous TiO2 shells for enhanced plasmonic photoelectrochemical assay of nitrogen dioxide

Trace concentrations of nitrogen dioxide have toxic effects on natual environment and health of mankind. Therefore, it is urgent to develop a high-performance NO2 sensor. In this work, a new type of hypersensitive NO2 photoelectrochemical (PEC) sensor was prepared by using the in situ Ag2O/Ag/amorphous TiO2 Z-scheme hollow spheres modified indium tin oxide (ITO) electrodes. First of all, colloidal silica granules were used as a template to prepare the SiO2@amorphous TiO2. Then, the template etching and silver-sodium cationic exchange were performed in sequence. Further reduced by ethanol, the Ag/amorphous TiO2 hollow spheres were obtained. Exposure to phosphate buffer solution (PBS) containing NO2, the Ag2O nanoparticles produced in situ increased the photoanode current based on Ag/amorphous TiO2 in a proportional manner. During this period, Ag was partially converted to Ag2O, which was proved by the XPS and Auger spectra. Silver nanoparticles sandwiched between amorphous TiO2 and Ag2O play a dual role in enhancing photoelectric response. They are both plasmon photosensitizer and Z-scheme charge medium. The unique sensitizing mechanism makes the PEC sensor have the advantages of good stability, outstanding selectivity, high sensitivity, low energy consumption and cost-effectiveness.

An epoxysilane modified indium tin oxide electrode for the determination of PAK 2: Application in human serum samples

In this study, a sensitive immunosensor was developed for the first time for p21-activated kinase 2 (PAK 2) detection. In the design of the immunosensor, 3-glycidoxypropyltrimethoxysilane (GPTMS) was utilized as an ITO electrode modification material for anti-PAK 2 antibody immobilization. This molecule had epoxy group, which was reactive to amino groups of antibodies. Anti-PAK 2 antibodies were also used as biomolecules for sensitive interaction for PAK 2 antigen. In the presence of PAK 2 antigens, high impedance signal was observed when the process followed by using Electrochemical Impedance Spectroscopy technique (EIS). Apart from EIS technique, Cyclic Voltammetry (CV), Square Wave Voltammetry (SWV) and Single Frequency Impedance (SFI) techniques were utilized. Microscopic surface characterizations of immunosensor fabrication steps were performed by using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The immunosensor exhibited good sensitivity and selectivity for PAK 2 antigen detection. A linear calibration curve between EIS response and PAK 2 concentration was obtained in the range of 0.005–0.075 pg/mL with the detection limit of 1.5 fg/mL. It had good repeatability, excellent reproducibility and high stability. Additionally, this immunosensor can be reused by simple application protocol. Furthermore, it had good recovery for PAK 2 antigen detection in human serum samples. The good recovery illustrated that the developed immunosensor was a promising tool for PAK 2 detection in practical applications.

Enzymatic in situ generation of covalently conjugated electron acceptor of PbSe quantum dots for high throughput and versatile photoelectrochemical bioanalysis

Most of the photoelectrochemical (PEC) bioassays need to immobilize biomolecules on electrodes, which lead to tedious modification processes, damaged biomolecules, as well as crippled sensitivity/accuracy and low throughput of the performances. To overcome these drawbacks, we now introduce an exquisitely split-mode (which separates the bioreaction (performed in microplates) from the PEC detection (conducted in PEC cell)) cathodic photoelectrochemistry for probing versatile biocatalytic events with high throughput. Specifically, the enzymatically in situ generated 1,2-bezoquinone was covalently attached onto the PbSe quantum dots (QDs) modified indium tin oxide (ITO) (ITO/PbSe) photocathode through the connector of chitosan (CS). And the attached 1,2-bezoquinone acted as an efficient electron acceptor to promote the cathodic photocurrent of the ITO/PbSe electrode, enabling us to probe quinones-generating oxidoreductase (by taking horseradish peroxidase (HRP) as a model) coupled biocatalytic cascades including the alkaline phosphatase (ALP)/HRP and the glucose oxidase (GOx)/HRP cascades. Quantitative probing for ALP activity in a wide linear range of 5.0 × 10−3 to 10 U/L with the detection limit of 1.2 × 10−3 U/L was realized. While a wide linear range of 5.0 × 10−8 to 1.0 × 10−4 moL/L with a quite low detection limit of 1.0 × 10−8 moL/L was obtained for the glucose assay. In addition, this testing protocol was also extended to an immunoassay (taking carcinoembryonic antigen (CEA) as an example) using HRP as a catalytic tracer. The developed bioassays show high sensitivity and good selectivity for CEA detection in the linear range from 0.1 pg/mL to 100 ng/mL with a detection limit of 0.02 pg/mL. Moreover, the proposed detection has distinctive merits because it not only avoids the adverse effects of the surface confined biomolecules for crippling the signal transduction, but also it has enhanced throughput.

Controlled Layer-By-Layer Deposition of Carbon Nanotubes on Electrodes for Microbial Fuel Cells

Carbon nanotubes (CNTs) and polyelectrolyte poly(allylamine hydrochloride) (PAH) composite modified indium tin oxide (ITO) electrodes, by a layer-by-layer (LBL) self-assembly technique, was evaluated as an anode for microbial fuel cells (MFCs). The bioelectrochemistry of Shewanella loihica PV-4 in an electrochemical cell and the electricity generation performance of MFCs with multilayer (CNTs/PAH)n-deposited ITO electrodes as an anode were investigated. Experimental results showed that the current density generated on the multilayer modified electrode increased initially and then decreased as the deposition of the number of layers (n = 12) increased. Chronoamperometric results showed that the highest peak current density of 34.85 ± 2.80 mA/m2 was generated on the multilayer (CNTs/PAH)9-deposited ITO electrode, of which the redox peak current of cyclic voltammetry was also significantly enhanced. Electrochemical impedance spectroscopy analyses showed a well-formed nanostructure porous film on the surface of the multilayer modified electrode. Compared with the plain ITO electrode, the multilayered (CNTs/PAH)9 anodic modification improved the power density of the dual-compartment MFC by 29%, due to the appropriate proportion of CNTs and PAH, as well as the porous nanostructure on the electrodes.

Uniform and dense copper nanoparticles directly modified indium tin oxide electrode for non-enzymatic glucose sensing

Low-cost and facile preparation of high-performance nanomaterials has aroused research passion to build non-enzymatic glucose sensor. In this work, uniform and dense Cu nanoparticles were immobilized on ITO electrode by one-step electrochemical deposition, where the Cu nanoparticles/ITO (Cu NPs/ITO) electrode were directly employed for glucose sensing without additional binder. During the deposition, the complexing agent and deposition potential were adjusted to realize the morphology-controlled of Cu NPs and further decrease the aggregation of nanoparticles. Subsequently, the concentration of sodium citrate, deposition potential, NaOH concentration and detection potential on the electrooxidation performances of Cu NPs/ITO were investigated systematically by electrochemical analysis. Under the optimal conditions, the sensor exhibited a high sensitivity of 1005.09μAmM−1cm−2 and a wide linear range of 0.0033–3.9019mM (R2=0.998), benefiting from the high conductivity, large surface area and directly electron transfer of binder-free Cu nanoparticles with uniform and dense morphology. Great stability, reproducibility, selectivity and feasible human serum analysis of Cu NPs/ITO were also demonstrated in glucose sensing. Owing to its low-cost, one-step preparation and great performance, this Cu NPs/ITO electrode can be a promising candidate for the construction of non-enzymatic glucose sensor.

Novel electrochemical sensing platform based on integration of molecularly imprinted polymer with Au@Ag hollow nanoshell for determination of resveratrol

An electrochemical sensor is developed based on molecularly imprinted polymer (MIP) and Au@Ag hollow nanoshell modified indium tin oxide (ITO) electrodes (MIP/Au@Ag/ITO) for resveratrol (Res) determination. Au@Ag bimetallic hollow nanoshells were prepared by electrodeposition, and followed with a simple replacement reaction. A layer of MIP was then synthesized in situ on the Au@Ag surface by electro-polymerization, with Res acting as template molecule and o-phenylenediamine as functional monomer. Hexacyanoferrate was used as electrochemical probe to generate signals, and the electrochemical behaviors of Res-MIP/Au@Ag/ITO were explored by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). A linear range from 2.0 × 10−11 to 9.0 × 10−9 M for measuring Res was obtained, with a low detection limit of 7.1 × 10−12 M (S/N = 3). With good stability and selectivity, this newly developed sensor has been successfully applied to Res measurement in grape seed extract.

Efficient organic-inorganic hybrid cathode interfacial layer enabled by polymeric dopant and its application in large-area polymer solar cells

An organic-inorganic hybrid cathode interfacial layer (CIL) was developed by doping ZnO with the naphthalene-diimide based derivative NDI-PFNBr. It was found the resulting organic-inorganic hybrid CIL showed apparently improved conductivity and could act as an effective cathode interlayer to modify indium tin oxide (ITO) transparent electrodes. As a result, by employing the blend of PTB7-Th:PC71BM as the photoactive layer, the inverted polymer solar cells (PSCs) exhibited a remarkable enhancement of power conversion efficiency (PCE) from 8.52% for the control device to 10.04% for the device fabricated with the hybrid CIL. Moreover, all device parameters were simultaneously improved by using this hybrid CIL. The improved open-circuit voltage ( V OC) was attributed to the reduced work function of the ITO cathode, whereas the enhancements in fill factor (FF) and short-circuit current density ( J SC) were assigned to the increased conductivity and more effective charge extraction and collection at interface. Encouragingly, when the thickness of the hybrid CIL was increased to 80 nm, the resulting device could still keep a PCE of 8.81%, exhibiting less thickness dependence. Considering these advantages, 16 and 93 cm2 large-area PSCs modules were successfully fabricated from the hybrid CIL by using doctor-blade coating techniques and yielded a remarkable PCE of 8.05% and 4.49%, respectively. These results indicated that the hybrid CIL could be a promising candidate to serve as the cathode interlayer for high-performance large-area inverted PSCs.

Highly sensitive electrochemical immunosensor for golgi protein 73 based on proximity ligation assay and enzyme-powered recycling amplification

Golgi protein 73 (GP73) is a potential hepatocellular carcinoma serum marker with better sensitivity and specificity. In this study, a highly sensitive electrochemical immunosensor which combines the highly selective proximity ligation assay (PLA) and highly efficient enzyme-powered recycling amplification has been developed for GP73 determination. PLA is triggered by affinity binding of two labelled antibody-DNA (P1-RAb and P2-MAb) to target protein, resulting in increased specificity. The formed immunocomplex hybrids with DNA2 to realize the release of methylene blue labelled mononucleotides fragment with the help of exonuclease III, which acts as the power of recycling amplification. The fragment can diffuse easily to the nafion modified indium tin oxide electrode surface and a strong electrochemical signal can be detected. Under the optimized conditions, the enhanced electrochemical intensity has a linear relationship with the concentration of GP73 in the range of 0.3 pg mL−1 to 6.0 ng mL−1 with the detection limit of 0.10 pg mL−1. The developed immunosensor has been applied to detect the GP73 in the clinical serum samples with satisfactory results.

Enhanced Device Efficiency and Long-Term Stability via Boronic Acid-Based Self-Assembled Monolayer Modification of Indium Tin Oxide in a Planar Perovskite Solar Cell

Interfacial engineering is essential for the development of highly efficient and stable solar cells through minimizing energetic losses at interfaces. Self-assembled monolayers (SAMs) have been shown as a handle to tune the work function (WF) of indium tin oxide (ITO), improving photovoltaic cell performance and device stability. In this study, we utilize a new class of boronic acid-based fluorine-terminated SAMs to modify ITO surfaces in planar perovskite solar cells. The SAM treatment demonstrates an increase of the WF of ITO, an enhancement of the short-circuit current, and a passivation of trap states at the ITO/[poly(3,4ethylenedioxylenethiophene):poly(styrenesulfonic acid)] interface. Device stability improves upon SAM modification, with efficiency decreasing only 20% after one month. Our work highlights a simple treatment route to achieve hysteresis-free, reproducible, stable, and highly efficient (16%) planar perovskite solar cells.

Site Selective Arrangement of Gold Nanoparticles on Aminosilane Self-Assembled Monolayer Modified Indium Tin Oxide

Site Selective Arrangement of Gold Nanoparticles on Aminosilane Self-Assembled Monolayer Modified Indium Tin Oxide

Graphene oxide-gold nanozyme for highly sensitive electrochemical detection of hydrogen peroxide

We fabricated a nafion/graphene oxide-gold nanoparticle (GO-AuNP) hybrid modified indium tin oxide (ITO) electrode and proposed an electrochemical method to detect hydrogen peroxide (H2O2) using 3,3,5,5,-tetramethylbenzidine (TMB) as a redox mediator. The GO-AuNP hybrids were employed as nanozymes, which function as peroxidase mimics and show highly effective catalytic activity. Based on the high catalytic activity, enzyme mimics were entrapped on the ITO electrode to construct an electrochemical H2O2 sensor by coating nafion polymer. During the catalytic reaction, the peroxidase substrate TMB was oxidized to form the TMB oxidation product, which not only produces a blue color detected by absorbance change, but also generates an electrochemical current. As a result, both spectrophotometric and electrochemical methods were used to determine H2O2 concentration. The spectrophotometric detection displayed a linearity for H2O2 concentration from 10 μM to 5 mM (r2 = 0.989), with an estimated detection limit of 2 μM. In the electrochemical detection, the TMB peak current had a good linear relationship with H2O2 concentration from 10 nM to 10 mM, with an estimated detection limit of 1.9 nM, which was much lower than that of the spectrophotometric method result.

Evaluating the efficiency of a photoelectrochemical electrode constructed with photosystem II-enriched thylakoid membrane fragments

The photoelectrochemical electrode has been intensively studied in recent years as a means of generating electricity from light through the use of intact thylakoid membranes or highly purified photosystem II. PSII-enriched thylakoid membrane fragments (PSII-BBY), also have the potential to construct the photoelectrochemical anode. In this study, we examined the feasibility of utilizing PSII-BBY preparations to construct a relatively inexpensive photoelectrochemical anode with a comparable current density and a reasonable stability. Intact thylakoid membrane based photoelectrochemical electrode was also constructed to compare with the PSII-BBY based photoelectrochemical electrode with respect to the protein activity and current density. In addition, the practicability of replacing the popular gold nanoparticle modified gold slide with multi-walled carbon nanotube modified indium tin oxide coated slides was tested. In order to understand the surface change during slide surface modification, an atomic force microscope (AFM) was used to image the topography of the slide. Above all, we observed a current density of 20.44 ± 1.58 μA/cm2 when PSII-BBY was used to construct the photoelectrochemical anode. Moreover, the PSII-BBY based photoelectrochemical anode showed high stability over time with the current decreasing at a rate of 0.78%/h.

Formation of Homogeneous Epinephrine-Melanin Solutions to Fabricate Electrodes for Enhanced Photoelectrochemical Biosensing.

The development of a simple but effective surface modification method is very important for the construction of biosensing interfaces. In this work, a postsynthetic water-soluble epinephrine-melanin (EPM) prepared from the self-polymerization of epinephrine has been demonstrated as an alternative of the widely used in situ formed polydopamine (PDA) for the surface coating of TiO2 nanoparticles and the construction of a photoelectrochemical (PEC) biosensing interface. In contrast to the formation of insoluble aggregates in solution for dopamine, a homogeneous solution was obtained for epinephrine after the self-polymerization. The use of EPM as a postsynthetic material enables the surface coating of TiO2 with the simple drop-casting method. Compared with the widely used dip-coating method for in situ PDA modification, the developed drop-casting method based on the use of water-soluble postsynthetic EPM saves more time, avoids the waste of bulk solution, and undoubtedly decreases the batch-to-batch inconsistencies. The simple coating of commercially available TiO2 nanoparticles with EPM greatly enhances the PEC performance due to the charge transfer property of EPM. The application of EPM in the construction of the PEC biosensing interface was demonstrated by the immobilization of a model biorecognition element (prostate specific antigen (PSA) antibody) onto EPM modified indium tin oxide (ITO) photoanode. Sensitive detection of PSA with high selectivity and stability was obtained on the basis of the biological recognition ability of PSA antibody. This work may renew the use of postsynthetic melanin-like biopolymers in other fields.

Modifying the Surface Properties of Indium Tin Oxide with Alcohol-Based Monolayers for Use in Organic Electronics

Transparent conductive oxides (TCOs) serve a critical function in many devices, such as organic light-emitting diodes (OLEDs) and organic photovoltaics (OPVs). To optimize the performances of these devices, it is desirable to tune the interface between the TCO and the next functional layer of these devices. Self-assembled monolayers prepared from phosphonic acids and silanes are commonly used to tune the properties and performance of this interface, including its surface energy, work function, and durability. Here, we report a new form of self-assembled monolayers for modifying indium tin oxide (ITO), a standard TCO used in OLEDs and OPVs. The ITO surfaces were modified with a series of distinct alcohol reagents. Stabilities of these alcohol-based monolayers were compared with modifications derived from silanes and phosphonic acids, which are commonly used in the literature and industrial processes. Work functions and surface energies of these modified substrates were determined using ultraviolet photoele...

Cd2+-Doped Amorphous TiO2 Hollow Spheres for Robust and Ultrasensitive Photoelectrochemical Sensing of Hydrogen Sulfide.

Hydrogen sulfide is a highly toxic molecule to human health, but high-performance detection of it remains a challenge. Herein, we report an ultrasensitive photoelectrochemical (PEC) sensor for H2S by modifying indium tin oxide (ITO) electrodes with Cd2+-doped amorphous TiO2 hollow spheres, which are prepared by templating against colloidal silica particles followed by a cadmium-sodium cation exchange reaction. The amorphous TiO2 hollow spheres act as both the probing cation carrier and the photoelectric beacon. Upon exposure to sulfide ions, the photocurrent of the functionalized photoanode proportionately decreases in response to the formation of CdS nanoparticles. The decreased photocurrent could be attributed to the mismatching bandgap between the amorphous TiO2 and CdS nanoparticles: the photoexcited electrons and holes from amorphous TiO2 are transferred to the conduction band and valence band of CdS, respectively, and then recombined. The decrease in photocurrent is linear with the concentration of sulfide ions in the range from 1 to 10 000 pmol L-1 with a detection limit of 0.36 pmol L-1. Enabled by a unique sensitization mechanism, this PEC sensor features excellent performance in a wide linear range, high selectivity and sensitivity, high stability, and low fabrication cost.

Low energy nitrogen ion beam implanted tungsten trioxide thin films modified indium tin oxide electrode based acetylcholine sensor

Abstract This paper reports the fabrication of non-enzymatic acetylcholine (ACh) electrochemical sensor based on low energy nitrogen ion (100 keV) implanted tungsten trioxide (WO3) thin films modified indium tin oxide (ITO) electrode. The WO3 thin films deposited on ITO by spin coating technique was subjected to nitrogen ion implantation with the optimum fluence of 1 × 1015 ions/cm2. The implanted electrode was characterized by X-ray diffraction, field emission scanning electron microscopy (FESEM), photoluminescence spectra, Hall Effect measurements, cyclic voltammetry and amperometry. The implanted WO3 modified ITO electrode induces desirable changes in the crystal structure, surface morphology and electron mobility. Compared with pristine WO3/ITO, nitrogen ion implanted WO3/ITO displayed improved electrical conductivity and electrocatalytic activity towards ACh oxidation in 0.1 M potassium hydroxide solution (KOH). Amperometric measurements showed that the fabricated electrode had a wide linear response range of 0.1–8000 µM, higher sensitivity of 140.57 ± 0.62 mA/M/cm2 and the lowest detection limit of 28 nM, which are superior among the non-enzymatic ACh electrochemical sensors. The proposed sensor exhibits an excellent anti-interferential ability, good stability and reproducibility and successfully applied for the determination of ACh levels in human serum samples.

Immunosensor Employing Stable, Solid 1-Amino-2-naphthyl Phosphate and Ammonia-Borane toward Ultrasensitive and Simple Point-of-Care Testing.

Biosensors for ultrasensitive point-of-care testing require dried reagents with long-term stability and a high signal-to-background ratio. Although ortho-substituted diaromatic dihydroxy and aminohydroxy compounds undergo fast redox reactions, they are not used as electrochemical signaling species because they are readily oxidized and polymerized by dissolved oxygen. In this report, stable, solid 1-amino-2-naphthyl phosphate (1A2N-P) and ammonia-borane (H3N-BH3) are respectively employed as a substrate for alkaline phosphatase (ALP) and a reductant for electrochemical-chemical (EC) redox cycling. ALP converts 1A2N-P to 1-amino-2-naphthol (1A2N), which is then employed in EC redox cycling using H3N-BH3. The oxidation and polymerization of 1A2N by dissolved oxygen is significantly prevented in the presence of H3N-BH3. The electrochemical measurement is performed without modification of indium-tin oxide (ITO) electrodes with electrocatalytic materials. For comparison, nine aromatic dihydroxy and aminohydroxy compounds, including 1A2N, are evaluated to achieve fast EC redox cycling, and four strong reductants, including H3N-BH3, are evaluated to achieve a low background level. The combination of 1A2N and H3N-BH3 allows the achievement of a very high signal-to-background ratio. When the newly developed combination is applied to the detection of creatine kinase-MB (CK-MB), the detection limit for CK-MB is ∼80 fg/mL, indicating that the combination allows ultrasensitive detection. The concentrations of CK-MB in clinical serum samples, determined using the developed system, are in good agreement with the concentrations obtained using a commercial instrument. Thus, the use of stable, solid 1A2N-P and H3N-BH3 along with bare ITO electrodes is highly promising for ultrasensitive and simple point-of-care testing.