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1. Supersensitive CeO _x -based nanocomposite sensor for the electrochemical detection of hydroxyl free radicals

   https://doi.org/10.1039/D1NR00015B  

   Duanghathaipornsuk, Surachet; Kim, Dong-Shik; Phares, Tamara L.; Li, Cheng-Han; Jinschek, Joerg R.; Alba-Rubio, Ana C. (March 2021, Nanoscale)

   null (Ed.)

   It is well known that an excess of hydroxyl radicals (˙OH) in the human body is responsible for oxidative stress-related diseases. An understanding of the relationship between the concentration of ˙OH and those diseases could contribute to better diagnosis and prevention. Here we present a supersensitive nanosensor integrated with an electrochemical method to measure the concentration of ˙OH in vitro. The electrochemical sensor consists of a composite comprised of ultrasmall cerium oxide nanoclusters (<2 nm) grafted to a highly conductive carbon deposited on a screen-printed carbon electrode (SPCE). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to analyze the interaction between cerium oxide nanoclusters and ˙OH. The CV results demonstrated that this electrochemical sensor had the capacity of detecting ˙OH with a high degree of accuracy and selectivity, achieving a consistent performance. Additionally, EIS results confirmed that our electrochemical sensor was able to differentiate ˙OH from hydrogen peroxide (H 2 O 2 ), which is another common reactive oxygen species (ROS) found in the human body. The limit of detection (LOD) observed with this electrochemical sensor was of 0.6 μM. Furthermore, this nanosized cerium oxide-based electrochemical sensor successfully detected in vitro the presence of ˙OH in preosteoblast cells from newborn mouse bone tissue. The supersensitive electrochemical sensor is expected to be beneficially used in multiple applications, including medical diagnosis, fuel–cell technology, and food and cosmetic industries. 

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2. Electrochemical Fabrication of 2D CuO Nanosheets on Pt Foil as a Highly Sensitive Non‐Enzymatic Glucose Sensor

   https://doi.org/10.1002/slct.202300104  

   Bhangoji, Jagdish C.; Barile, Christopher J.; Shendage, Suresh S. (July 2023, ChemistrySelect)

   Abstract A simple and environmentally‐friendly approach was developed to synthesize 2D CuO nanosheets using electrochemical deposition. The formed 2D CuO nanosheets (NSs) exhibit numerous advantageous properties such as no toxicity, high electrical conductivity, large active surface area, and a p‐type semiconducting nature with a band gap of 1.2 eV. A sensitive electrochemical sensor was constructed for the amperometric detection of glucose to take advantage of these characteristics. The fabricated sensor displayed an excellent sensitivity of 2710 μA mM⁻¹ cm⁻²along with a wide linear range of 0.001–1.0 mM and a lower limit of detection of 0.8 μM (S/N=3). Additionally, the modified electrode possesses high selectivity and good stability. The outstanding electrocatalytic performance of the electrode is attributed to a large active surface area, unique structural morphology, and the high conductivity of the 2D CuO nanosheets. 

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3. DNA-Templated Silver Nanoclusters as Dual-Mode Sensitive Probes for Self-Powered Biosensor Fueled by Glucose

   https://doi.org/10.3390/nano13081299  

   Gupta, Akhilesh Kumar; Krasnoslobodtsev, Alexey V. (April 2023, Nanomaterials)

   Nanomaterials have been extensively explored in developing sensors due to their unique properties, contributing to the development of reliable sensor designs with improved sensitivity and specificity. Herein, we propose the construction of a fluorescent/electrochemical dual-mode self-powered biosensor for advanced biosensing using DNA-templated silver nanoclusters (AgNCs@DNA). AgNC@DNA, due to its small size, exhibits advantageous characteristics as an optical probe. We investigated the sensing efficacy of AgNCs@DNA as a fluorescent probe for glucose detection. Fluorescence emitted by AgNCs@DNA served as the readout signal as a response to more H2O2 being generated by glucose oxidase for increasing glucose levels. The second readout signal of this dual-mode biosensor was utilized via the electrochemical route, where AgNCs served as charge mediators between the glucose oxidase (GOx) enzyme and carbon working electrode during the oxidation process of glucose catalyzed by GOx. The developed biosensor features low-level limits of detection (LODs), ~23 μM for optical and ~29 μM for electrochemical readout, which are much lower than the typical glucose concentrations found in body fluids, including blood, urine, tears, and sweat. The low LODs, simultaneous utilization of different readout strategies, and self-powered design demonstrated in this study open new prospects for developing next-generation biosensor devices. 

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4. Peroxidase-mimicking Ce–hemin–MOFs/GO composite for enzyme-free electrochemical detection of H2O2

   https://doi.org/10.1016/j.jelechem.2025.119744  

   Ghaedamini, Hamidreza; Khanal, Riwaj; Kim, Dong-Shik (February 2026, Journal of Electroanalytical Chemistry)

   Hydrogen peroxide (H2O2), a key reactive oxygen species (ROS), plays a crucial role in cellular signaling; however, at elevated concentrations, it contributes to oxidative stress and is implicated in various pathologies. Herein, we report the development of a novel electrochemical biosensor based on cerium–hemin metal–organic frameworks (Ce–hemin–MOFs ) integrated with graphene oxide (GO) for the sensitive and selective detection of H2O2. The Ce–hemin–MOFs were synthesized via a coordination-driven assembly of cerium ions and hemin, yielding petal-like crystalline microstructures with intrinsic peroxidase-mimicking activity. Incorporation of GO significantly enhanced the electrical conductivity of the composite. The sensor demonstrated a broad linear detection range (0.01–10 mM), a low detection limit of 1.2 μM, and strong selectivity against common biological interferents. Furthermore, the developed sensor enabled real-time detection of H2O2 released from human prostate cancer (22Rv1) cells, demonstrating its practical potential for monitoring oxidative processes associated with cellular pathophysiology. This highlights the broader applicability of MOFs-based sensing platforms in biomedical research and disease diagnostics. 

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5. Stretchable Nanofiber-Based Felt as a String Electrode for Potential Use in Wearable Glucose Biosensors

   https://doi.org/10.3390/s24041283  

   Seufert, Bianca; Thomas, Sylvia; Takshi, Arash (February 2024, Sensors)

   Nanofiber technology is leading the revolution of wearable technology and provides a unique capability to fabricate smart textiles. With the novel fabrication technique of electrospinning, nanofibers can be fabricated and then manufactured into a durable conductive string for the application of smart textiles. This paper presents an electrospun nanofiber mesh-based (NF-Felt) string electrode with a conducting polymer coating for an electrochemical enzymatic glucose sensor. The surface area of a nanofiber matrix is a key physical property for enhanced glucose oxidase (GOx) enzyme binding for the development of an electrochemical biosensor. A morphological characterization of the NF-Felt string electrode was performed using scanning electron microscopy (SEM) and compared with a commercially available cotton–polyester (Cot-Pol) string coated with the same conducting polymer. The results from stress–strain testing demonstrated high stretchability of the NF-Felt string. Also, the electrochemical characterization results showed that the NF-Felt string electrode was able to detect a glucose concentration in the range between 0.0 mM and 30.0 mM with a sensitivity of 37.4 μA/mM·g and a detection limit of 3.31 mM. Overall, with better electrochemical performance and incredible flexibility, the NF-Felt-based string electrode is potentially more suitable for designing wearable biosensors for the detection of glucose in sweat. 

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