Electroactive Molecularly Imprinted Polymer Nanoparticles (eMIPs) for Label-free Detection of Glucose: Toward Wearable Monitoring.

The diagnosis of diabetes mellitus (DM) affecting 537 million adults worldwide relies on invasive and costly enzymatic methods that have limited stability. Electroactive polypyrrole (PPy)-based molecularly imprinted polymer nanoparticles (eMIPs) have been developed that rival the affinity of enzymes whilst being low-cost, highly robust, and facile to produce. By drop-casting eMIPs onto low-cost disposable screen-printed electrodes (SPEs), sensors have been manufactured that can electrochemically detect glucose in a wide dynamic range (1 µm-10 mm) with a limit of detection (LOD) of 26 nm. The eMIPs sensors exhibit no cross reactivity to similar compounds and negligible glucose binding to non-imprinted polymeric nanoparticles (eNIPs). Measurements of serum samples of diabetic patients demonstrate excellent correlation (>0.93) between these eMIPs sensor and the current gold standard Roche blood analyzer test. Finally, the eMIPs sensors are highly durable and reproducible (storage >12 months), showcasing excellent robustness and thermal and chemical stability. Proof-of-application is provided via measuring glucose using these eMIPs sensor in a two-electrode configuration in spiked artificial interstitial fluid (AISF), highlighting its potential for non-invasive wearable monitoring. Due to the versatility of the eMIPs that can be adapted to virtually any target, this platform technology holds high promise for sustainable healthcare applications via providing rapid detection, low-cost, and inherent robustness.

Multiplex antibiotic susceptibility testing of urinary tract infections using an electrochemical lab-on-a-chip.

Urinary tract infections (UTIs) represent the most prevalent type of outpatient infection, with significant adverse health and economic burdens. Current culture-based antibiotic susceptibility testing can take up to 72 h resulting in ineffective prescription of broad-spectrum antibiotics, poor clinical outcomes and development of further antibiotic resistance. We report an electrochemical lab-on-a-chip (LOC) for testing samples against seven clinically-relevant antibiotics. The LOC contained eight chambers, each housing an antibiotic-loaded hydrogel (cephalexin, ceftriaxone, colistin, gentamicin, piperacillin, trimethoprim, vancomycin) or antibiotic-free control, alongside a resazurin bulk-modified screen-printed electrode for electrochemical detection of metabolically active bacteria using differential pulse voltammetry. Antibiotic susceptibility in simulated UTI samples or donated human urine with either Escherichia coli or Klebsiella pneumoniae could be established within 85 min. Incorporating electrochemical detection onto a LOC provides an inexpensive, simple method for the sensitive determination of antibiotic susceptibility that is significantly faster than using a culture-based approach.

Enhancing sensitivity towards electrochemical miRNA detection using an affordable paper-based strategy.

In the era of liquid biopsy, microRNAs emerge as promising candidates for the early diagnosis and prognosis of cancer, offering valuable insights into the disease's development. Among all the existing analytical approaches, even if traditional approaches such as the nucleic acid amplification ones have the advantages to be highly sensitive, they cannot be used at the point-of-care, while sensors might be poorly sensitive despite their portability. In order to improve the analytical performance of existing electroanalytical systems, we demonstrate how a simple chromatographic paper-based disk might be useful to rationally improve the sensitivity, depending on the number of preconcentration cycles. A paper-based electrochemical platform for miRNA detection has been developed by modifying a paper-based electrode with a methylene blue (MB)-modified single-stranded sequence (ssDNA) complementary to the chosen miRNA, namely miR-224 that is associated with lung cancer. A detection limit of ca. 0.6 nM has been obtained in spiked human serum samples. To further enhance the sensitivity, an external chromatographic wax-patterned paper-based disk has been adopted to preconcentrate the sample, and this has been demonstrated both in standard and in serum solutions. For each solution, three miR-224 levels have been preconcentrated, obtaining a satisfactory lowering detection limit of ca. 50 pM using a simple and sustainable procedure. This approach opens wide possibilities in the field of analytical and bioanalytical chemistry, being useful not only for electrochemistry but also for other architectures of detection and transduction.

Computational aptamer design for spike glycoprotein (S) (SARS CoV-2) detection with an electrochemical aptasensor.

A new bioinformatic platform (APTERION) was used to design in a short time and with high specificity an aptamer for the detection of the spike protein, a structural protein of SARS-CoV-2 virus, responsible for the COVID-19 pandemic. The aptamer concentration on the carbon electrode surface was optimized using static contact angle and fluorescence method, while specificity was tested using differential pulse voltammetry (DPV) associated to carbon screen-printed electrodes. The data obtained demonstrated the good features of the aptamer which could be used to create a rapid method for the detection of SARS-CoV-2 virus. In fact, it is specific for spike also when tested against bovine serum albumin and lysozyme, competitor proteins if saliva is used as sample to test for the virus presence. Spectrofluorometric characterization allowed to measure the amount of aptamer present on the carbon electrode surface, while DPV measurements proved the affinity of the aptamer towards the spike protein and gave quantitative results. The acquired data allowed to conclude that the APTERION bioinformatic platform is a good method for aptamer design for rapidity and specificity. KEY POINTS: • Spike protein detection using an electrochemical biosensor • Aptamer characterization by contact angle and fluorescent measurements on electrode surface • Computational design of specific aptamers to speed up the aptameric sequence time.

Electrochemically assisted DNA and thioaromatic assembly as sensing and antifouling interface for food allergens.

Food allergies have become a global issue and are estimated to affect approximately 220 million people worldwide. Allergy to peanuts can easily become life-threatening and induce anaphylactic reactions. Mislabeling and cross-contamination during food processing can occur in the frame of world population growth and pose a serious health issue. As the mandatory allergen list is not uniform worldwide, the development of routine analytical strategies with high specificity and sensitivity is a demanding task to aid in the rapid identification of allergenic foods. In this work, an electrochemical aptasensor for Ara h1 peanut allergen was developed by immobilizing the specific aptamer by the inserting method. First, a layer of p-aminothiophenol (p-ATP) was immobilized on the gold surface of screen-printed electrodes (GSPE) to improve the aptamer insertion and reduce the fouling effects at the electrode surface. The grafting of the p-ATP and Ara h1 aptamer on the GSPE surface was monitored by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). The resulting disposable aptasensor allowed for indirect electrochemical detection of Ara h1 protein in the presence of 5 mM ferro/ferricyanide as a redox probe. The electrochemical response upon aptamer-target interaction was monitored in the concentration range 1-250 nM, and two limits of detection in the nanomolar range were estimated based on DPV (2.78 nM Ara h1) and EIS (0.82 nM Ara h1) measurements. The aptasensor was successfully applied to real sample analysis.

Utilizing COVID-19 as a Model for Diagnostics Using an Electrochemical Sensor.

This paper reports a rapid and sensitive sensor for the detection and quantification of the COVID-19 N-protein (N-PROT) via an electrochemical mechanism. Single-frequency electrochemical impedance spectroscopy was used as a transduction method for real-time measurement of the N-PROT in an immunosensor system based on gold-conjugate-modified carbon screen-printed electrodes (Cov-Ag-SPE). The system presents high selectivity attained through an optimal stimulation signal composed of a 0.0 V DC potential and 10 mV RMS-1 AC signal at 100 Hz over 300 s. The Cov-Ag-SPE showed a log response toward N-PROT detection at concentrations from 1.0 ng mL-1 to 10.0 µg mL-1, with a 0.977 correlation coefficient for the phase (θ) variation. An ML-based approach could be created using some aspects observed from the positive and negative samples; hence, it was possible to classify 252 samples, reaching 83.0, 96.2 and 91.3% sensitivity, specificity, and accuracy, respectively, with confidence intervals (CI) ranging from 73.0 to 100.0%. Because impedance spectroscopy measurements can be performed with low-cost portable instruments, the immunosensor proposed here can be applied in point-of-care diagnostics for mass testing, even in places with limited resources, as an alternative to the common diagnostics methods.

Copper Micro-Flowers for Electrocatalytic Sensing of Nitrate Ions in Water.

The progressive increase in nitrate's (NO3-) presence in surface and groundwater enhances environmental and human health risks. The aim of this work is the fabrication and characterization of sensitive, real-time, low-cost, and portable amperometric sensors for low NO3- concentration detection in water. Copper (Cu) micro-flowers were electrodeposited on top of carbon screen-printed electrodes (SPCEs) via cyclic voltammetry (with voltage ranging from -1.0 V to 0.0 V at a scan rate of 0.1 V s-1). The obtained sensors exhibited a high catalytic activity toward the electro-reduction in NO3-, with a sensitivity of 44.71 µA/mM. They had a limit of detection of 0.87 µM and a good dynamic linear concentration range from 0.05 to 3 mM. The results were compared to spectrophotometric analysis. In addition, the devices exhibited good stability and a maximum standard deviation (RSD) of 5% after ten measurements; reproducibility, with a maximum RSD of 4%; and repeatability after 10 measurements with the RSD at only 5.63%.

Modified Gold Screen-Printed Electrodes for the Determination of Heavy Metals.

Screen-printed electrodes (SPEs) are reliable, portable, affordable, and versatile electrochemical platforms for the real-time analytical monitoring of emerging analytes in the environmental, clinical, and agricultural fields. The aim of this study was to evaluate the electrochemical behavior of gold screen-printed electrodes (SPGEs) modified with molecules containing amino (Tr-N) or α-aminophosphonate (Tr-P) groups for the selective and sensitive detection of the toxic metal ions Pb2+ and Hg2+ in aqueous samples. After optimizing the analytical parameters (conditioning potential and time, deposition potential and time, pH and concentration of the supporting electrolyte), anodic square wave stripping voltammetry (SWASV) was used to evaluate and compare the electrochemical performance of bare or modified electrodes for the detection of Hg2+ and Pb2+, either alone or in their mixtures in the concentration range between 1 nM and 10 nM. A significative improvement in the detection ability of Pb2+ ions was recorded for the amino-functionalized gold sensor SPGE-N, while the presence of a phosphonate moiety in SPGE-P led to greater sensitivity towards Hg2+ ions. The developed sensors allow the detection of Pb2+ and Hg2+ with a limit of detection (LOD) of 0.41 nM and 35 pM, respectively, below the legal limits for these heavy metal ions in drinking water or food, while the sensitivity was 5.84 µA nM-1cm-2 and 10 µA nM-1cm-2, respectively, for Pb2+ and Hg2+. The reported results are promising for the development of advanced devices for the in situ and cost-effective monitoring of heavy metals, even in trace amounts, in water resources.

Multiphysics Modeling of Electrochemical Impedance Spectroscopy Responses of SAM-Modified Screen-Printed Electrodes.

In this work, we present a multiphysics modeling approach capable of simulating electrochemical impedance spectroscopy (EIS) responses of screen-printed electrodes (SPEs) modified with self-assembled monolayers of 11-Mercaptoundecanoic acid (MUA). Commercially available gold SPEs are electrochemically characterized through experimental cyclic voltammetry and EIS measurements with 10 mM [Fe(CN)6]3-/4- redox couple in phosphate buffered saline before and after the surface immobilization of MUA at different concentrations. We design the multiphysics model through COMSOL Multiphysics® based on the 3D geometry of the devices under test. The model includes four different physics considering the metal/solution interface electrochemical phenomena, the ion and electron potentials and currents, and the measurement set-up. The model is calibrated through a set of experimental measurements, allowing the tuning of the parameters used by the model. We use the calibrated model to simulate the EIS response of MUA-modified SPEs, comparing the results with experimental data. The simulations fit the experimental curves well, following the variation of MUA concentration on the surface from 1 µM to 100 µM. The EIS parameters, retrieved through a CPE-modified Randles' circuit, confirm the consistency with the experimental data. Notably, the simulated surface coverage estimates and the variation of charge transfer resistance due to MUA-immobilization are well matched with their experimental counterparts, reporting only a 2% difference and being consistent with the experimental electrochemical behavior of the SPEs.

Screen-Printed Electrodes-A Promising Tool for Antineoplastic Drug Detection (Cisplatin and Bleomycin) in Biological Samples.

Cancer remains one of the leading causes for death worldwide. Palliative chemotherapy is vital for certain cancer patients, highlighting the critical need for treatment monitoring tools to prevent drug accumulation and mitigate the risk of high toxicity. Therefore, our aim was to evaluate the potential of screen-printed electrodes for the development of sensitive and accurate biosensors for the detection/quantification of antineoplastic drugs. To this purpose, we developed a cisplatin sensor. By functionalizing the gold electrode with human serum albumin and by collecting the electrochemical signal obtained in a H2O2 solution, through voltammetry measurements, we were able to correlate the current measured at 430 mV with the concentration of cisplatin present in human serum samples, with a correlation coefficient of R2 = 0.99. Also, a bleomycin biosensor was developed and proven functional, but further optimization steps were employed in order to improve the accuracy. The developed biosensors have a detection range of 0.0006-43.2 mg/mL for cisplatin and 0.23-7.56 µg/mL for bleomycin in the serum samples. Our preliminary results show that these biosensors can facilitate the real-time monitoring of cisplatin and bleomycin serum levels, allowing healthcare professionals to tailor treatment strategies based on individual patient responses.

Duplex Electrochemical Microfluidic Sensor for COVID-19 Antibody Detection: Natural versus Vaccine-Induced Humoral Response.

The rapid transmission and resilience of coronavirus disease 2019 (COVID-19) have led to urgent demands in monitoring humoral response for effective vaccine development, thus a multiplex co-detection platform to discriminate infection-induced from vaccine-induced antibodies is needed. Here a duplex electrochemical immunosensor for co-detection of anti-nucleocapsid IgG (N-IgG) and anti-spike IgG (S-IgG) is developed by using a two-working electrode system, via an indirect immunoassay, with antibody quantification obtained by differential pulse voltammetry. The screen-printed electrodes (SPEs) are modified by carbon black and electrodeposited gold nanoflowers for maximized surface areas, enabling the construction of an immunological chain for S-IgG and N-IgG electrochemical detection with enhanced performance. Using an optimized immunoassay protocol, a wide linear range between 30-750 and 20-1000 ng mL-1 , and a limit of detection of 28 and 15 ng mL-1 are achieved to detect N-IgG and S-IgG simultaneously in serum samples. This duplex immunosensor is then integrated in a microfluidic device to obtain significantly reduced detection time (≤ 7 min) while maintaining its analytical performance. The duplex microfluidic immunosensor can be easily expanded into multiplex format to achieve high throughput screening for the sero-surveillance of COVID-19  and other infectious diseases.

Electrochemical sensors for the determination of 4-ethylguaiacol in wine.

The development of an electrochemical procedure for the determination of 4-ethylguaiacol and its application to wine analysis is described. Modified screen-printed carbon electrodes (SPCEs) with fullerene C60 (C60) have been shown to be efficient in this kind of analysis. The developed activated C60/SPCEs (AC60/SPCEs) were adequate for the determination of 4-ethylguaicol, showing a linear range from 200 to 1000 µg/L, a reproducibility of 7.6% and a capability of detection (CCß) value of 200 µg/L, under optimized conditions. The selectivity of the AC60/SPCE sensors was evaluated in the presence of possibly interfering compounds, and their practical applicability was demonstrated  in the analysis of different wine samples obtaining recoveries ranging from 96 to 106%.

Boron-doped diamond nanosheet volume-enriched screen-printed carbon electrodes: a platform for electroanalytical and impedimetric biosensor applications.

This paper focuses on the development of a novel electrode based on boron-doped diamond nanosheet full-volume-enriched screen-printed carbon electrodes (BDDPE) for use as an impedimetric biosensor. Impedimetric biosensors offer high sensitivity and selectivity for virus detection, but their use as point-of-care devices is limited by the complexity of nanomaterials' architecture and the receptor immobilisation procedures. The study presents a two-step modification process involving the electroreduction of diazonium salt at the BDDPE and the immobilisation of antibodies using zero-length cross-linkers for a selective impedimetric biosensor of Haemophilus influenzae (Hi). The incorporation of diamond nanosheets into BDDPE leads to enhanced charge transfer and electrochemical behaviour, demonstrating greatly improved electrochemically active surface area compared with unmodified screen-printed electrodes (by 44% and 10% on average for [Ru(NH3)6]Cl2 and K3[Fe(CN)6], respectively). The presented sensing system shows high specificity towards protein D in Hi bacteria, as confirmed by negative controls against potential interference from other pathogens, with an estimated tolerance limit for interference under 12%. The Hi limit of detection by electrochemical impedance spectroscopy was 1 CFU/mL (measured at - 0.13 V vs BDDPE pseudo-reference), which was achieved in under 10 min, including 5 min sample incubation in the presence of the analyte.

Electrochemical sensing platform based on screen-printed carbon electrode modified with plasma polymerized acrylonitrile nanofilms for determination of bupropion.

A original electrochemical sensing platform, based on screen-printed electrodes modification with plasma polymerized acrylonitrile (pp-AN) nanofilms is proposed. For that purpose, plasma-enhanced chemical vapor deposition (PECVD) process was conducted in a parallel plate (13.56 MHz) plasma reactor for 2 min with discharge power of 10 W. The surface topography and electrochemical properties of prepared sensors were investigated by X-ray photoelectron spectroscopy, scanning electron microscopy, energy dispersion spectroscopy, electrochemical impedance spectroscopy, and cyclic voltammetry. The electrochemical characteristics of pp-AN/SPCE and pp-AN/SPAuE sensors was investigated for model redox pair [Fe(CN)6]4-/3-. Conducted research confirmed the excellent chemical stability, durability, wide potential window, high signal-to-noise (S/N) ratio, and, most importantly, the ability to standardize the sensors. The pp-AN/SPCE sensor was applied to the determination of bupropion, an antidepressant drug whose intake has increased dramatically during the COVID-19 pandemic. The voltammetric response of pp-AN/SPCE for BUP was linear in two concentration ranges of 0.63-10.0 and 10.0-50.0 µmol L-1, with a detection limit of 0.21 µmol L-1. Satisfactory recoveries (96.2-102%) and good precision (RSD below 4.1%) obtained for environmental and biological samples confirmed the usefulness of the sensor for the analysis of various kinds of samples.

Shedding light on the calculation of electrode electroactive area and heterogeneous electron transfer rate constants at graphite screen-printed electrodes.

We present in detail the most known and commonly used methods for the calculation of electrode electroactive area ([Formula: see text]) and heterogeneous electron transfer rate constants ([Formula: see text]). The correct procedure for the calculation of these parameters is often disregarded due to either lack of a minimum theoretical background or oversimplification of each method's limitations and prerequisites. The aim of this work is to provide the theoretical background as well as a detailed guide for the implementation of these measurements by impressing upon the electrochemists the parameters that need to be considered so that the obtained results are safe and useful. Using graphite screen-printed electrodes, [Formula: see text], and [Formula: see text] were calculated with different methods and techniques. Data are compared and discussed.

A wearable electrode based on copper nanoparticles for rapid determination of paraquat.

The application of copper-based nanoparticles synthesized via green synthesis and their integration with a wearable electrode is reported for designing a flexible catalytic electrode on a glove for onsite electroanalysis of paraquat. A copper precursor and an orange extract from Citrus reticulata are used to synthesize an economical electrocatalytic material for supporting the selective and sensitive detection of paraquat. The electrode yields multidimensional fingerprints due to two redox couples in a square wave voltammogram, corresponding to the presence of paraquat. The developed lab-on-a-finger sensor provides the fast electroanalysis of paraquat within 10 s, covering a wide range from 0.50 to 1000 µM, with a low detection limit down to 0.31 µM and high selectivity. It is also possible to use this sensor at a fast scan rate as high as 6 V s-1 (< 0.5 s for a scan). This wearable glove sensor allows the user to directly touch and analyze samples, such as surfaces of vegetables and fruits, to screen the contamination. It is envisioned that these glove-embedded sensors can be applied to the on-site analysis of food contamination and environments.

Recent Advances in the Development of Portable Electrochemical Sensors for Controlled Substances.

This review article summarizes recent achievements in developing portable electrochemical sensing systems for the detection and/or quantification of controlled substances with potential on-site applications at the crime scene or other venues and in wastewater-based epidemiology. Electrochemical sensors employing carbon screen-printed electrodes (SPEs), including a wearable glove-based one, and aptamer-based devices, including a miniaturized aptamer-based graphene field effect transistor platform, are some exciting examples. Quite straightforward electrochemical sensing systems and methods for controlled substances have been developed using commercially available carbon SPEs and commercially available miniaturized potentiostats. They offer simplicity, ready availability, and affordability. With further development, they might become ready for deployment in forensic field investigation, especially when fast and informed decisions are to be made. Slightly modified carbon SPEs or SPE-like devices might be able to offer higher specificity and sensitivity while they can still be used on commercially available miniaturized potentiostats or lab-fabricated portable or even wearable devices. Affinity-based portable devices employing aptamers, antibodies, and molecularly imprinted polymers have been developed for more specific and sensitive detection and quantification. With further development of both hardware and software, the future of electrochemical sensors for controlled substances is bright.

Carbon Inks-Based Screen-Printed Electrodes for Qualitative Analysis of Amino Acids.

Due to the great significance of amino acids, a substantial number of research studies has been directed toward the development of effective and reliable platforms for their evaluation, detection, and identification. In order to support these studies, a new electrochemical platform based on PANI/ZnO nanowires' modified carbon inks screen-printed electrodes was developed for qualitative analysis of electroactive amino acids, with emphasis on tyrosine (Tyr) and tryptophan (Trp). A comparative investigation of the carbon ink before and after modification with the PANI/ZnO was performed by scanning electron microscopy and by Raman spectroscopy, confirming the presence of PANI and ZnO nanowires. Electrochemical investigations by cyclic voltammetry and electrochemical impedance spectroscopy have shown a higher charge-transfer rate constant, which is reflected into lower charge-transfer resistance and higher capacitance values for the PANI/ZnO modified ink when compared to the simple carbon screen-printed electrode. In order to demonstrate the electrochemical performances of the PANI/ZnO nanowires' modified carbon inks screen-printed electrodes for amino acids analysis, differential pulse voltammograms were obtained in individual and mixed solutions of electroactive amino acids. It has been shown that the PANI/ZnO nanowires' modified carbon inks screen-printed electrodes allowed for tyrosine and tryptophan a peak separation of more than 100 mV, enabling their screening and identification in mixed solutions, which is essential for the electrochemical analysis of proteins within the proteomics research field.

Interaction between Benzo[a]anthracene 7,2-dione 7-oxime (BZA) and calf thymus dsDNA using electroanalytical genosensor.

In the present study, the objective was to evaluate in situ interaction between Benzo[a]anthracene 7,2-dione 7-oxime (BZA) and calf thymus dsDNA (ct-dsDNA) using electroanalytical genosensor. Analytical techniques based on Ultraviolet/Visible (UV-Vis) spectroscopy and electroanalytical were used to investigate the interaction processes in solution and immobilized on carbon screen-printed electrodes modified with electrochemical mediator Meldola blue. In addition, was possible to evaluate the degree of damage caused to the genetic material by the analyte through of toxicity estimate (S%). The interaction evaluated by genosensor showed processes of intercalation, degradation, and breaks of the double strand of ct-dsDNA, suggesting that the interaction simulates highly toxic (values varying from 0.6 to 0.8 µA in 48 h of interaction), such as 8-oxoguanine (+0.48 V), which is a by-product of guanine oxidation. Furthermore, monitoring A (+1.10 V) after 1 h showed an S% value between 50 and 90%, indicative of high toxicity, and monitoring G (+0.85 V), which showed S>90%, indicated no toxicity after 10 min. Overall, the electroanalytical genosensor developed in a miniaturized system displayed good reproducibility and stability over time being a quick alternative for assesses the degree of toxicity between toxic xenobiotics and biologically electroactive molecules, such as DNA.

Glucose sensing on screen-printed electrochemical electrodes based on porous graphene aerogel @prussian blue.

As one of the three major chronic diseases, diabetes often causes many complications, which can affect various parts of the body and even threaten the life of the patients. At present, the situation of diabetes in the world is quite serious. Accurate detection of blood glucose is very important for the diagnosis, treatment and medication of diabetes as well as the self-management of diabetic patients. In this paper, an electrochemical glucose biosensor was developed based on screen-printed electrode (SPE) modified with composite material of graphene aerogel (GA) and Prussian blue (PB) (denoted as GA@PB), which was fabricated via chemical reduction using L-ascorbic acid as a reducing agent through a freeze-drying process. Glucose was specifically captured by glucose oxidase (GOx) which were immobilized into the GA@PB by chitosan. The structure and performance of the sensor were characterized by scanning electron microscopy (SEM), Raman spectroscopy measurements, Fourier transform infrared spectrometer (FTIR), cyclic voltammetry (CV) and amperometric detection. The sensor exhibited a linear range of 0.5-6.0 mmol·L-1 with limit of detection (LOD) of 0.15 mmol·L-1, indicating that the combination of graphene aerogel and Prussian blue possess well conductivity and catalytic performance.