Development Of Biosensors Research Articles

Carbon quantum dots composite for enhanced selective detection of dopamine with organic electrochemical transistors

A compact organic electrochemical transistors (OECT) sensor enriched with carbon quantum dots (CQDs) was developed to enhance the transconductance of an electropolymerized poly(3,4-ethylenedioxythiophene) (PEDOT) film, enabling the precise and selective detection of dopamine (DA). Accurate monitoring of DA levels is critical for diagnosing and managing related conditions. Incorporating CQDs, we have achieved a remarkable up to threefold increase in current at the DA detection peak in differential pulse voltammetry. This enhancement showcases superior selectivity even in the presence of high concentrations of interferents like uric acid and ascorbic acid. This material significantly boosts the sensitivity of OECTs for DA detection, delivering an amperometric response with a detection limit of 55 nM and a broader detection range (1 − 500 µM). Our results underscore the potential of low-dimensional carbonaceous materials in creating cost-effective, high-sensitivity devices for detecting DA and other biomolecules. This breakthrough sets the stage for the development of next-generation biosensors for point-of-care diagnostics.Graphical

A biosensor based on carbon dots-protein interactions for specific and sensitive detection of pepsin in saliva

Salivary pepsin has emerged as a promising biomarker for rapid screening and diagnosis of gastroesophageal reflux disease (GERD). Pepsin mainly exists in strongly acidic environments and exhibits its highest activity. However, the poor stability of most fluorescent sensors in strong acidic environments brings a significant challenge for pepsin detection. Herein, an innovative biosensor was developed for the highly specific and sensitive detection of pepsin on the basis of green-emitting ionic liquid-based carbon dots (G-IL-CDs) conjugated with whey proteins (WPs). The G-IL-CDs exhibited aggregation-induced fluorescence enhancement when interacting with WP, and the fluorescence intensity decreased after incubation with pepsin due to the disruption of the aggregation structure. This strategy is highly selective for pepsin due to the strongly acidic environment in which other proteases are inactivated. Under optimal experimental conditions, this biosensor successfully detected pepsin in real human saliva with a satisfying recovery. Furthermore, this study not only developed a CDs-based sensor for detecting pepsin but also laid a solid theoretical foundation for the future development of novel biosensors combining CDs and proteins.

Triple-Branch Catalytic Assembly DNAzyme Motivated DNA Tweezer for Sensitive and Reliable mecA Gene Detection in Staphylococcus aureus.

Staphylococcus aureus (S. aureus, SA) is one of the most common bacteria in nosocomial infections. Sensitive and efficient analysis of methicillin-resistance of SA is crucial for improving the nursing performance of pneumonia. However, methicillin-resistance analysis with favorable sensitivity and specificity in an enzyme-free manner remains a huge challenge. This paper presents the development of a new fluorescent biosensor for detecting mecA gene using a triple-branch catalytic hairpin assembly (CHA) triggered DNAzyme switch-based DNA tweezer. The SA from the samples are immobilized on the plate's surface using the protein A antibody. The biosensor possesses several key features. Firstly, it utilizes dual signal amplification processes, specifically the triple-branch CHA and DNAzyme controlled DNA tweezer-based signal recycling, to enable mecA detection on the plate. This design enhances the method's sensitivity, resulting in a low limit of detection of 1.5 fM. Secondly, the biosensor does not rely on enzymes for mecA analysis, ensuring a high level of stability during target analysis. Lastly, the method demonstrates a remarkable selectivity by accurately distinguishing target sequences from non-target sequences. The proposed biosensor, which does not require enzymes and has a high level of sensitivity, offers a viable platform for the rapid and simple quantification of mecA in SA.

Amplification‐free sub-femtomolar monitoring of SARS-CoV-2-RNA in serum samples using cDNA-modified MoS2 field-effect transistor

The rapid spread of infectious diseases, exemplified by the well-known case of COVID-19, which has led to a global pandemic, has garnered increasing attention toward the development of simple and efficient biosensors for diagnosis. In this study, a field-effect transistor (FET)-based biosensor offers an alternative and promising solution for the diagnosis of clinical COVID-19. Molybdenum disulfide (MoS2) in a channel FET modified with a probe complementary DNA (cDNA) can sensitively detect selected specific sequences from SARS-CoV-2 through hybridization. MoS2 was modified with probe cDNA and exhibited a linear concentration range of 1 fM to 0.1 nM in both phosphate-buffered saline (PBS) and serum samples, with low limits of detection (LOD) of 0.21 and 0.73 fM, respectively. In addition, it demonstrated a rapid response time of 3 min in clinical samples. The developed biosensor is capable of analyzing RNA from 19 clinical samples. These results indicate that the biosensor successfully distinguished between healthy and infected samples, which is consistent with the RT-PCR results (kappa coefficient = 1). Additionally, a notable difference was observed between the RdRp samples of SARS-CoV-2 and SARS-CoV. Therefore, we believe that this study offers a reliable and appealing option for the diagnosis of COVID-19.

Target-mediated silver deposition-based electrochemical biosensor for highly sensitive detection of human chorionic gonadotropin

As a glycoprotein hormone, human chorionic gonadotropin (hCG) is an established marker for pregnancy test. On the basis of the target-mediated silver deposition (TSD), in this work, we report the development of an amplification-free electrochemical biosensor for the highly sensitive detection of hCG. The detection of hCG involves the use of the affinity peptide-modified electrode for hCG capture (the CGGSSPPLRINRHILTR peptide containing the hCG-binding domain of the PPLRINRHILTR sequence is used as the affinity peptide), the oxidation of the diol sites of the glycan chains on hCG hormones into aldehyde groups by NaIO4, and the deposition of silver nanoparticles (AgNPs) for the solid-state voltammetric stripping analysis. Due to the deposition of multiple AgNPs while the solid-state Ag/AgCl voltammetric process has a high signal-to-noise ratio, the TSD-based electrochemical biosensor can be applied to the highly sensitive detection of hCG without the need for signal amplification. Under optimal conditions, the stripping current increased linearly with an increasing hCG concentration over the range from 1.0 to 25 mIU/mL, with a detection limit of 0.45 mIU/mL. Owing to the high specificity of the hCG-binding peptide PPLRINRHILTR, this electrochemical hCG biosensor exhibits high selectivity. The results of the quantitative assay of hCG in urine samples at the concentrations of 25, 10, and 1.0 mIU/mL are desirable, indicating the good anti-interference capability. As the TSD-based electrochemical biosensor allows the amplification-free detection of low-abundance hCG, it is easy to use and cost-effective, showing great promise in point-of-care assay of hCG for pregnancy test.

Palladium–iridium nanocubes modified with a high-affinity DNA aptamer as paired viral diagnostic and therapeutic tools

The COVID-19 pandemic emphasizes the need for the development of molecular tools that can be used as effective diagnostic and therapeutic agents. Herein we investigate the potential of aptamer-dressed nanomaterials both as diagnostics and therapeutics using SARS-CoV-2 as a model. The nanomaterials are based on the palladium-iridium (Pd–Ir) nanocubes modified with monomeric, dimeric or trimeric aptamers that exhibit varying affinities for the spike protein of SARS-CoV-2. These nanomaterials were first examined for diagnostic potential through the creation of a nanozyme-linked aptamer assay (NLAA) that takes advantage of the peroxidase-mimicking activity of Pd–Ir nanocubes. The trimeric aptamer-based NLAA demonstrated a limit of detection (LOD) of 9.3 ​× ​103 cp/mL for pseudoviruses expressing the spike protein of SARS-CoV-2, 172- and 12.9-fold lower than that of the monomeric and dimeric aptamer-based NLAAs, respectively. Upon testing with 60 clinical saliva samples, the trimeric aptamer-based NLAA achieved a specificity of 100 ​% and a sensitivity of 86.7 ​%. The same nanomaterials were also examined for the ability to block viral entry to host cells. The trimeric aptamer-conjugated nanocubes exhibited a superior neutralizing ability, with an IC50 value of 6.4 pM, 2.7- and 10.1-fold lower than that of the dimeric and monomeric aptamer nanocubes. Moreover, the trimeric aptamer-conjugated nanocubes exhibited excellent biostability and biocompatibility. Overall, our study provides a framework for combating future viral pandemics through the development of a paired biosensor and neutralizing agent made of the same aptamer-modified nanomaterial that recognizes an important viral surface protein like the spike protein of SARS-CoV-2.

Development of a graphene field effect transistor-based immersible biosensor for immunodetection of the birch pollen allergen Bet v 1 in air samples

Pollen traps, the current gold standard to determine pollen load and thereby the allergy season, are not sufficient to determine the allergenic risk. Therefore, the establishment of highly sensitive assays for allergen measurement is of highest interest. Herein, a graphene field-effect transistor (GFET) was constructed on an interdigitated electrodes chip to develop an immersible biosensor, which was used to detect the major birch pollen allergen Bet v 1. Graphene was wet-transferred on interdigitated electrodes that contain a reference electrode used as a liquid gate in the GFET. Using a standard ELISA protocol, two different anti-Bet v 1 antibodies were chosen and immobilized on graphene for the specific capture of the target allergen. The sensitivity of the GFET biosensor was evaluated using a standard Ag/AgCl liquid gate electrode and a reference electrode when the chip was immersed in Bet v 1-containing solutions. The results showed a higher performance and sensitivity for Bet v 1 detection compared to a mediator release method, one of the most sensitive assays for allergen detection. Compared with conventional methods of allergen detection, these immersible biosensors significantly improved the speed and level of detection providing the foundation of a point-of-need platform for in-field application. Furthermore, the proposed technique provides both a new biosensor for allergen detection and a strategy for designing low-cost integrated biosensors.

RECENT ADVANCEMENT IN ELECTROCHEMICAL BIOSENSOR BASED ON REDOX ENZYME COMPOSITE MODIFIED ELECTRODE FOR THE DETECTION OF BIOMOLECULES

Recent developments in electrochemical biosensors have resulted in new applications in a variety of disciplines, such as clinical diagnosis, food processing quality control, and environmental monitoring. The electrochemical biosensor is a widely used sensing device that transmits an electrical signal from biological activities. Electrochemical biosensors have led to significant advancements in detecting various biomolecules such as uric acid, glucose, cholesterol, lactate, and DNA, including cancer biomarkers, viruses, and antibodies. An electrode is a vital part of this kind of sensor since it serves as a strong support for immobilizing biomolecules (enzyme, antibody, and nucleic acid) and allowing electron flow. Redox enzymes are the foundation of enzymatic electrochemical biosensors, which use oxidation or reduction reactions to detect a substrate, which is then converted into an electrical signal. Immobilizing enzymes onto solid supports is a common method to enhance the performance of an enzymatic electrochemical biosensor. However, there are some challenges, such as potential loss of enzyme activity, difficulties in maintaining enzyme stability, and issues related to the reproducibility and consistency of enzyme immobilization. This review covers all challenges in enzymatic electrochemical biosensors. Numerous new biosensor platforms are announced each year as researchers look for various electrode materials. Additionally, the researchers should familiarize themselves with the practical methods used in electrode production in order to build a successful biosensor. This review highlights current developments in modifying enzyme-immobilized biosensors for detection of different biomolecules. The article further describes methods of enzyme immobilization and various enzymes with different nanomaterials for the development of novel enzymatic electrochemical biosensors.

Emerging Diagnostic Methods Using Paper-based Electrochemical Biosensors

The development of paper-based electrochemical biosensors has brought about a paradigm shift in the diagnostics industry. These tools provide a portable, affordable, and easy-to-use platform for point-of-care (POC) testing. This has been transformed by the use of electrochemical detection techniques in paper-based analytical devices, which allow for the accurate and insightful assessment of a wide range of chemical analytes. These modified paper-based analytical gadgets have received significant recognition for their inherent benefits in the field of POC. Consequently, the sensitivity and practicality of electrochemical biosensors made of paper-based materials show great promise. They also have several other beneficial features, such as the ability to transport liquids independently, decreased resistance, low manufacturing costs, and environmental friendliness. This study examines the latest developments in paper-based electrochemical biosensing technologies and considers how they might be used in food safety, environmental monitoring, and in developing diagnostic techniques.

A NOVEL ELECTROCHEMICAL BIOSENSOR BASED ON CREATININE DEIMINASE FOR CREATININE ANALYSIS

This work presents the development of a new electrochemical biosensor based on creatinine deiminase for the determination of creatinine concentration in biological samples. The optimal method for immobilizing bioselective elements on the electrode surface was selected, specifically the covalent binding of creatinine deiminase in a BSA matrix using glutaraldehyde. The biosensors prepared in this way exhibited the highest sensitivity to creatinine and high reproducibility in the fabrication of biomembranes. The biosensor demonstrated a low limit of detection of creatinine, high signal stability (RSD = 3%), significant storage stability, and a wide linear range, enabling the detection of both normal and pathological creatinine concentrations in biological fluids. The study also investigated the influence of working solution parameters, such as ionic strength, buffer capacity, pH, and protein content, on the biosensor’s performance. The main analytical characteristics of the proposed electrochemical biosensor indicate its potential use for monitoring creatinine concentration in biological samples.

Electrodeposited ZnO Nanostructures on ITO Surfaces: Exploring Their Efficacy for Cholesterol Biosensing Applications

In this study, ZnO nanostructures were prepared by electrochemical anodization of electrodeposited Zn on ITO/glass substrates for cholesterol detection. The efficiency of the developed ZnO nanostructures in the detection of the Cholesterol oxidase (ChOx) enzyme was determined by the cyclic voltammetry method. The XRD and SEM results confirmed the synthesis of ZnO nanostructures prepared by the anodization method with various parameters. The effect of electrodeposition and anodization time on the morphology was observed. Cyclic voltammetry of ZnO/Zn/ITO/glass and Pt/ZnO/Zn/ITO/glass electrodes in electrolytes with various cholesterol concentrations was performed. The detection limit of the obtained Pt/ZnO/Zn/ITO/glass structured electrode was calculated as 0.965x10-3M. The resulting material with a layered structure may have potential applications in electrochemical sensors and biosensors in biomedical applications. In addition to biosensing performance, this study proposes a new approach for the development of ZnO-based biosensors that does not require expensive infrastructure and raw material costs, making it possible to develop high-sensitivity biosensor electrodes with lower detection limits with improvements to be made in future studies.

Complementary Metal-Oxide-Semiconductor-Based Magnetic and Optical Sensors for Life Science Applications.

Optical and magnetic sensing methods are integral to both research and clinical applications in biological laboratories. The ongoing miniaturization of these sensors has paved the way for the development of point-of-care (PoC) diagnostics and handheld sensing devices, which are crucial for timely and efficient healthcare delivery. Among the various competing sensing and circuit technologies, CMOS (complementary metal-oxide-semiconductor) stands out due to its distinct cost-effectiveness, scalability, and high precision. By leveraging the inherent advantages of CMOS technology, recent developments in optical and magnetic biosensors have significantly advanced their application in life sciences, offering improved sensitivity, integration capabilities, and reduced power consumption. This paper provides a comprehensive review of recent advancements, focusing on innovations in CMOS-based optical and magnetic sensors and their transformative impact on biomedical research and diagnostics.

Identification of Podoplanin Aptamers by SELEX for Protein Detection and Inhibition of Platelet Aggregation Stimulated by C-Type Lectin-like Receptor 2.

Tumor cell-induced platelet aggregation (TCIPA) is a mechanism for the protection of tumor cells in the bloodstream and the promotion of tumor progression and metastases. The platelet C-type lectin-like receptor 2 (CLEC-2) can bind podoplanin (PDPN) on a cancer cell surface to facilitate TCIPA. Selective blockage of PDPN-mediated platelet-tumor cell interaction is a plausible strategy for inhibiting metastases. In this study, we aimed to screen for aptamers, which are the single-stranded DNA oligonucleotides that form a specific three-dimensional structure, bind to specific molecular targets with high affinity and specificity, bind to PDPN, and interfere with PDPN/CLEC-2 interactions. The systematic evolution of ligands by exponential enrichment (SELEX) was employed to enrich aptamers that recognize PDPN. The initial characterization of ssDNA pools enriched by SELEX revealed a PDPN aptamer designated as A1 displaying parallel-type G-quadruplexes and long stem-and-loop structures and binding PDPN with a material with a dissociation constant (Kd) of 1.3 ± 1.2 nM. The A1 aptamer recognized both the native and denatured form of PDPN. Notably, the A1 aptamer was able to quantitatively detect PDPN proteins in Western blot analysis. The A1 aptamer could interfere with the interaction between PDPN and CLEC-2 and inhibit PDPN-induced platelet aggregation in a concentration-dependent manner. These findings indicated that the A1 aptamer is a candidate for the development of biosensors in detecting the levels of PDPN expression. The action by A1 aptamer could result in the prevention of tumor cell metastases, and if so, could become an effective pharmacological agent in treating cancer patients.

An in silico design method of a peptide bioreceptor for cortisol using molecular modelling techniques

Cortisol is established as a reliable biomarker for stress prompting intensified research in developing wearable sensors to detect it via eccrine sweat. Since cortisol is present in sweat in trace quantities, typically 8–140 ng/mL, developing such biosensors necessitates the design of bioreceptors with appropriate sensitivity and selectivity. In this work, we present a systematic biomimetic methodology and a semi-automated high-throughput screening tool which enables rapid selection of bioreceptors as compared to ab initio design of peptides via computational peptidology. Candidate proteins from databases are selected via molecular docking and ranked according to their binding affinities by conducting automated AutoDock Vina scoring simulations. These candidate proteins are then validated via full atomistic steered molecular dynamics computations including umbrella sampling to estimate the potential of mean force using GROMACS version 2022.6. These explicit molecular dynamic calculations are carried out in an eccrine sweat environment taking into consideration the protein dynamics and solvent effects. Subsequently, we present a candidate baseline peptide bioreceptor selected as a contiguous sequence of amino acids from the selected protein binding pocket favourably interacting with the target ligand (i.e., cortisol) from the active binding site of the proteins and maintaining its tertiary structure. A unique cysteine residue introduced at the N-terminus allows orientation-specific surface immobilization of the peptide onto the gold electrodes and to ensure exposure of the binding site. Comparative binding affinity simulations of this peptide with the target ligand along with commonly interfering species e.g., progesterone, testosterone and glucose are also presented to demonstrate the validity of this proposed peptide as a candidate baseline bioreceptor for future cortisol biosensor development.

Development of novel nanostructured biosensors for rapid detection of pathogens in clinical diagnostics

<p class="MsoNormal" style="text-align: justify; text-justify: inter-ideograph; line-height: 120%; mso-pagination: none; layout-grid-mode: char; mso-layout-grid-align: none; margin: 12.0pt 0cm 6.0pt 0cm;"><span lang="EN-US" style="font-size: 10.0pt; line-height: 120%; font-family: 'Times New Roman',serif;">The prompt and precise identification of microorganisms is crucial for successful clinical diagnostics and the prevention of infectious disease outbreaks. Traditional diagnostic methods often suffer from limitations such as extended processing durations, elevated expenses, and the necessity for specialized laboratory equipment. In this research, we propose the development of novel nanostructured biosensors that utilize the distinct characteristics of nanomaterials to improve the accuracy, specificity, and efficiency of identifying pathogens. These biosensors are created with the intention of offering point-of-care testing functionality, thus rendering them appropriate for utilization in a range of clinical settings. The integration of advanced nanotechnology with bioanalytical methods aims to create a reliable system for the real-time identification of bacterial, viral, and fungal pathogens. This review encompasses the design, fabrication, and testing of the biosensors, along with a comprehensive analysis of their performance in comparison to conventional diagnostic techniques. The results demonstrate the potential of nanostructured biosensors to revolutionize pathogen detection, offering significant improvements in efficiency and accuracy, which are essential for timely medical intervention and public health management.</span></p>

Fluorescent aptasensor based on competitive recognition strategies and point-of-care testing system for brain natriuretic peptide detection

Brain natriuretic peptide (BNP) is the preferred biomarker for clinical analysis, widely used in early screening and prognostic monitoring of cardiovascular and neurological diseases. Due to the low concentration and short half-life of BNP in the blood, its sensitive detection remains a challenge that must be overcome. With the rapid development of molecular diagnosis and point-of-care testing (POCT), developing a BNP biosensor with high sensitivity, good stability, accuracy, speed, and low-cost is of great significance for clinical applications and emergency diagnosis. However, BNP in human blood exists in various forms, and traditional fluorescence sensors may lead to overestimation of the concentration. In this work, we constructed an “on” fluorescent aptasensor based on competitive recognition strategy for quantitative detection of BNP, and built a fluorescence sensing detection system based on smartphone to achieve rapid on-site detection. We designed a specific aptamer labeled with carboxyfluorescein (FAM) with a simple structure and high biological affinity for selective capture of BNP, and utilized the large specific surface area and excellent fluorescence quenching effect of carboxylated graphene oxide (GO-COOH) as a carrier and quencher for the aptasensor. By optimizing experimental parameters such as aptamer and GO-COOH concentrations, as well as quenching/recovery time, linear sensitive detection of BNP was achieved in the concentration range of 0.01 ng/mL–10 ng/mL, with a detection limit as low as 10 pg/mL, good specificity, and excellent application potential in artificial serum spiking experiments. Additionally, a stable and sensitive fluorescence signal collection system has been developed to meet the needs of portable detection, breaking through the usage environment of traditional fluorescence detection equipment and filling the gap of portable fluorescence biosensing. In summary, we have creatively proposed a fluorescent aptasensor that enables rapid and sensitive detection of BNP and the development of low-cost fluorescent biosensors. The combination with POCT has shown broad application prospects and also provides some ideas for the fluorescence detection of other protein biomarkers.

Fundamentals and Exceptions of the LysR-type Transcriptional Regulators.

LysR-type transcriptional regulators (LTTRs) are emerging as a promising group of macromolecules for the field of biosensors. As the largest family of bacterial transcription factors, the LTTRs represent a vast and mostly untapped repertoire of sensor proteins. To fully harness these regulators for transcription factor-based biosensor development, it is crucial to understand their underlying mechanisms and functionalities. In the first part, this Review discusses the established model and features of LTTRs. As dual-function regulators, these inducible transcription factors exude precise control over their regulatory targets. In the second part of this Review, an overview is given of the exceptions to the "classic" LTTR model. While a general regulatory mechanism has helped elucidate the intricate regulation performed by LTTRs, it is essential to recognize the variations within the family. By combining this knowledge, characterization of new regulators can be done more efficiently and accurately, accelerating the expansion of transcriptional sensors for biosensor development. Unlocking the pool of LTTRs would significantly expand the currently limited range of detectable molecules and regulatory functions available for the implementation of novel synthetic genetic circuitry.

A non-enzymatic hydrogen peroxide biosensor based on cerium metal-organic frameworks, hemin, and graphene oxide composite

This study presents the development of a novel non-enzymatic electrochemical biosensor for the real-time detection of hydrogen peroxide (H2O2) based on a composite of cerium metal–organic frameworks (Ce-MOFs), hemin, and graphene oxide (GO). The Ce-MOFs served as an efficient matrix for hemin encapsulation, while GO enhanced the conductivity of the composite. Characterization techniques including scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, UV–vis spectroscopy, and thermogravimetric analysis (TGA) confirmed the successful integration of hemin into the Ce-MOFs. The Ce-MOFs@hemin/GO-modified sensor demonstrated sensitive H2O2 detection due to the exceptional electrocatalytic activity of Ce-MOFs@hemin and the high conductivity of GO. This biosensor exhibited a linear response to H2O2 concentrations from 0.05 to 10 mM with a limit of detection (LOD) of 9.3 μM. The capability of the biosensor to detect H2O2 released from human prostate carcinoma cells was demonstrated, highlighting its potential for real-time monitoring of cellular oxidative stress in complex biological environments. To further assess its practical applicability, the sensor was tested in human serum samples, yielding promising results with recovery values ranging from 94.50 % to 103.29 %. In addition, the sensor showed excellent selectivity against common interfering compounds due to the outstanding peroxidase-like activity of the composite.

Development of a Modular miRNA-Responsive Biosensor for Organ-Specific Evaluation of Liver Injury.

MicroRNAs (miRNAs) are increasingly being considered essential diagnostic biomarkers and therapeutic targets for multiple diseases. In recent years, researchers have emphasized the need to develop probes that can harness extracellular miRNAs as input signals for disease diagnostics. In this study, we introduce a novel miRNA-responsive biosensor (miR-RBS) designed to achieve highly sensitive and specific detection of miRNAs, with a particular focus on targeted organ-specific visualization. The miR-RBS employs a Y-structured triple-stranded DNA probe (Y-TSDP) that exhibits a fluorescence-quenched state under normal physiological conditions. The probe switches to an activated state with fluorescence signals in the presence of high miRNA concentrations, enabling rapid and accurate disease reporting. Moreover, the miR-RBS probe had a modular design, with a fluorescence-labeled strand equipped with a functional module that facilitates specific binding to organs that express high levels of the target receptors. This allowed the customization of miRNA detection and cell targeting using aptameric anchors. In a drug-induced liver injury model, the results demonstrate that the miR-RBS probe effectively visualized miR-122 levels, suggesting it has good potential for disease diagnosis and organ-specific imaging. Together, this innovative biosensor provides a versatile tool for the early detection and monitoring of diseases through miRNA-based biomarkers.

Precision engineering of surface defects of cerium oxide nanostructured fine particles for the multiplexed detection of electrolytes and glucose inside tissue models

The development of biosensors for the detection of glucose and electrolytes has become a crucial field of research nowadays due to the increasing incidence of long-term conditions. Specifically, the use of cerium oxide as a selective material for the detection of glucose is raising interest as an alternative to enzymatic sensors due to their stability and low-cost. This work demonstrates for the first time a significant improvement in the selectivity of glucose sensors based on cerium oxide nanostructured fine particles through doping with nickel ions and using pulse voltammetry for the sensing. By using nickel-doped cerium oxide fine particles, the sensitivity of the devices improved by 10-fold, and the selectivity when testing the devices against lactate increased by 68.5 % as compared to pure cerium oxide fine particles, with a limit of detection in the micromolar level. Crystallographic and compositional properties that led to such increase in sensitivity were determined, as a result of a presence of oxygen defects and amorphous domains at the surface of fine particles. This device could be adapted for the simultaneous measurement of glucose and sodium ions. The pulse voltametric approach enhanced the sensitivity of the sensors towards sodium ions, which reached a super-Nernstian sensitivity of 111 mV Log[Na+]-1, with a response time of 2 mins, and has been used for the testing of the electrodes in a practical environment using a skin-inspired material. This technology will pave the way for the development of miniaturised non-invasive wearable sensors real-time measurement of glucose and electrolytes in patients.