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Abstract DNA‐templated silver nanoclusters (AgNC@DNA) are a novel type of nanomaterial with advantageous optical properties. Only a few atoms in size, the fluorescence of nanoclusters can be tuned using DNA overhangs. In this study, we explored the properties of AgNCs manufactured on a short single‐stranded (dC)₁₂when adjacent G‐rich sequences (dG_N, withN = 3–15) were added. The ‘red’ emission of AgNC@dC₁₂with λ_MAX = 660 nm dramatically changed upon the addition of a G‐rich overhang with N_G = 15. The pattern of the emission–excitation matrix (EEM) suggested the emergence of two new emissive states at λ_MAX = 575 nm and λ_MAX = 710 nm. The appearance of these peaks provides an effective way to design biosensors capable of detecting specific nucleic acid sequences with low fluorescence backgrounds. We used this property to construct an NA‐based switch that brings AgNC and the G overhang near one another, turning ‘ON’ the new fluorescence peaks only when a specific miRNA sequence is present. Next, we tested this detection switch on miR‐371, which is overexpressed in prostate cancer. The results presented provide evidence that this novel fluorescent switch is both sensitive and specific with a limit of detection close to 22 picomoles of the target miR‐371 molecule. 

This study introduces a light-activated sensing strategy that integrates photosensitization with electrochemical detection. The sensor employs Eosin Y, a photosensitizer that generates singlet oxygen (1O2) via type II photosensitization. Immobilized within a thin polymer matrix on a carbon working electrode, Eosin Y produces 1O2, under green light (520 nm) illumination, initiating a redox process that yields a measurable current. To incorporate biosensing capabilities and enable self-powered operation, this 1O2 – mediated process was coupled with glucose oxidase (GOx) to construct a fully operational glucose biosensor. The addition of glucose reverses the current flow by causing GOx to compete for electrons, with the resulting current magnitude correlating with glucose concentration providing a sensitive measure of glucose. The biosensor, as proof-of-principle, demonstrated excellent performance over a range of glucose concentrations (0–73 mM), achieving a detection limit (LOD) of 2.8 mM for steady state photocurrent under oxygen-saturated conditions. This platform leverages light and 1O2 as stimuli for tunable, on-demand signal control, offering a novel approach for adaptive, real-time biosensing technologies. 

MicroRNAs (miRNAs) are small, non-coding RNAs that play critical roles in regulating gene expression and are implicated in various diseases, including cancer, cardiovascular disorders, and neurodegenerative diseases. Due to their diagnostic and prognostic significance, the development of sensitive, specific, and reliable detection methods for miRNAs has become a research priority. Nucleic-acid-based approaches offer unique advantages, including high specificity, the potential for amplification, and adaptability to various detection platforms. This review discusses recent advances in nucleic-acid-based strategies for miRNA detection, highlighting techniques such as hybridization-based methods, amplification strategies, CRISPR-based approaches, novel NV-diamond sensors, as well as their integration into point-of-care devices. 

Self-powered biosensors are innovative devices that can detect and analyze biological or chemical substances without the need for an external power source. These biosensors can convert energy from the surrounding environment or the analyte itself into electrical signals for sensing and data transmission. The self-powered nature of these biosensors offers several advantages, such as portability, autonomy, and reduced waste generation from disposable batteries. They find applications in various fields, including healthcare, environmental monitoring, food safety, and wearable devices. While self-powered biosensors are a promising technology, there are still challenges to address, such as improving energy efficiency, sensitivity, and stability to make them more practical and widely adopted. This review article focuses on exploring the evolving trends in self-powered biosensor design, outlining potential advantages and limitations. With a focal point on enzymatic biofuel cell power generation, this article describes various sensing mechanisms that employ the analyte as substrate or fuel for the biocatalyst’s ability to generate current. Technical aspects of biofuel cells are also examined. Research and development in the field of self-powered biosensors is ongoing, and this review describes promising areas for further exploration within the field, identifying underexplored areas that could benefit from further investigation. 

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.