Search Results (391)

The rapid and accurate detection of pathogenic bacteria and viruses is critical for infectious disease control and public health protection. While conventional methods (e.g., culture, microscopy, serology, and PCR) are widely used, they are often limited by lengthy processing times, high costs, and specialized equipment requirements. In recent years, metal nanocluster (MNC)-based biosensors have emerged as powerful diagnostic platforms due to their unique optical, catalytic, and electrochemical properties. This systematic review comprehensively surveys advancements in MNC-based biosensors for bacterial and viral pathogen detection, focusing on optical (colorimetric and fluorescence) and electrochemical platforms. Three key aspects are emphasized: (1) detection mechanisms, (2) nanocluster types and properties, and (3) applications in clinical diagnostics, environmental monitoring, and food safety. The literature demonstrates that MNC-based biosensors provide high sensitivity, specificity, portability, and cost-efficiency. Moreover, the integration of nanotechnology with biosensing platforms enables real-time and point-of-care diagnostics. This review also discusses the limitations and future directions of the technology, emphasizing the need for enhanced stability, multiplex detection capability, and clinical validation. The findings offer valuable insights for developing next-generation biosensors with improved functionality and broader applicability in microbial diagnostics. Full article

Cancer diagnosis requires alternative techniques that allow for early, non-invasive, or minimally invasive identification. Traditional methods, like tissue biopsies, are highly invasive and can be traumatic for patients. Liquid biopsy, a less invasive option, detects cancer biomarkers in body fluids such as blood and urine. However, early-stage cancer often presents low biomarker levels, making sensitivity a challenge for integrating liquid biopsy into early diagnosis. Recent studies revealed that extracellular vesicles (EVs) secreted by cells are apt markers for liquid biopsy. Detecting extracellular vesicles (EVs) for liquid biopsy faces challenges like low sensitivity, EV subtype heterogeneity, and difficulty isolating pure populations. Label-free methods, such as plasmonic biosensors and Raman spectroscopy, offer potential solutions by enabling direct analysis without markers, improving accuracy, and reducing complexity. This review paper discusses current challenges in EV-based liquid biopsy for cancer diagnosis and prognosis. It addresses the effective use of microfluidics and nano-plasmonic approaches to address these challenges. Enhancing label-free EV detection in liquid biopsy could revolutionize early cancer diagnosis by offering non-invasive, cost-effective, and rapid testing. This could improve patient outcomes through personalized treatment and ease the burden on healthcare systems. Full article

In this article, the role of downscaling in boosting the sensitivity of a novel label-free DNA sensor based on sub-10 nm dielectric-modulated transition metal dichalcogenide field-effect transistors (DM-TMD FET) is presented through a quantum simulation approach. The computational method is based on self-consistently solving the quantum transport equation coupled with electrostatics under ballistic transport conditions. The concept of dielectric modulation was employed as a label-free biosensing mechanism for detecting neutral DNA molecules. The computational investigation is exhaustive, encompassing the band profile, charge density, current spectrum, local density of states, drain current, threshold voltage behavior, sensitivity, and subthreshold swing. Four TMD materials were considered as the channel material, namely, MoS₂, MoSe₂, MoTe₂, and WS₂. The investigation of the scaling capability of the proposed label-free gate-all-around DM-TMDFET-based biosensor showed that gate downscaling is a valuable approach not only for producing small biosensors but also for obtaining high biosensing performance. Furthermore, we found that reducing the device size from 12 nm to 9 nm yields only a moderate improvement in sensitivity, whereas a more aggressive downscaling to 6 nm leads to a significant enhancement in sensitivity, primarily due to pronounced short-channel effects. The obtained results have significant technological implications, showing that miniaturization enhances the sensitivity of the proposed nanobiosensor. Full article

Paper-based electronics have emerged as a sustainable, low-cost, and flexible alternative to traditional substrates for electronics, particularly for disposable and wearable applications. This review outlines recent developments in paper-based devices, focusing on sensors and paper-based field-effect transistors (PFETs). Key fabrication techniques such as laser-induced graphene, inkjet printing, and screen printing have enabled the creation of highly sensitive and selective devices on various paper substrates. Material innovations, especially the integration of graphene, carbon-based materials, conductive polymers, and other novel micro- and nano-enabled materials, have significantly enhanced device performance. This review discusses modern applications of paper-based electronics, with a particular emphasis on biosensors, electrochemical and physical sensors, and PFETs designed for flexibility, low power, and high sensitivity. Advances in PFET architectures have further enabled the development of logic gates and memory systems on paper, highlighting the potential for fully integrated circuits. Despite challenges in durability and performance consistency, the field is rapidly evolving, driven by the demand for green electronics and the need for decentralized, point-of-care diagnostic tools. This paper also identifies detection strategies used in paper-based sensors, reviews limitations in the current fabrication methods, and outlines opportunities for the scalable production of multifunctional paper-based systems. This review addresses a critical gap in the literature by linking device-level innovation with real-world sensor applications on paper substrates. Full article

Background: Nanomaterial-based biosensors represent a transformative advancement in oral health diagnostics and therapeutics, offering superior sensitivity and selectivity for early disease detection compared to conventional methods. Their applications span prosthetic dentistry, where they enable the precise monitoring of dental implants, and theranostics for conditions such as dental caries, oral cancers, and periodontal diseases. These innovations promise to enhance proactive oral healthcare by integrating detection, treatment, and preventive strategies. Objectives: This review comprehensively examines the role of nanomaterial-based biosensors in dental theranostics, with a focus on prosthetic applications. It emphasizes their utility in dental implant surveillance, the early identification of prosthesis-related complications, and their broader implications for personalized treatment paradigms. Methods: A systematic literature search was conducted across PubMed, Scopus, and Web of Science for studies published between 2010 and early 2025. Keywords included combinations of “nanomaterials”, “biosensors”, “dentistry”, “oral health”, “diagnostics”, “therapeutics”, and “theranostics”. Articles were selected based on their relevance to nanomaterial applications in dental biosensors and their clinical translation. Results: The review identified diverse classes of nanomaterials—such as metallic nanoparticles, carbon-based structures, and quantum dots—whose unique physicochemical properties enhance biosensor performance. Key advancements include the ultra-sensitive detection of biomarkers in saliva and gingival crevicular fluid, the real-time monitoring of peri-implant inflammatory markers, and cost-effective diagnostic platforms. These systems demonstrate exceptional precision in detecting early-stage pathologies while improving operational efficiency in clinical settings. Conclusions: Nanomaterial-based biosensors hold significant promise for revolutionizing dental care through real-time implant monitoring and early complication detection. Despite challenges related to biocompatibility, scalable manufacturing, and rigorous clinical validation, these technologies may redefine oral healthcare by extending prosthetic device longevity, enabling personalized interventions, and reducing long-term treatment costs. Future research must address translational barriers to fully harness their potential in improving diagnostic accuracy and therapeutic outcomes. Full article

Herein, we report the use of a nanotechnology-based approach for the study of enzyme-functionalized mica surfaces. Atomic force microscopy (AFM) has been employed for the determination of the catalytic activity of single molecules of heme-containing cytochrome P450 CYP102A1 (CYP102A1) enzyme, which was immobilized on the surface of a mica chip. Height fluctuations in individual molecules of the enzyme were measured under near-native conditions by AFM measurements in liquid using a cantilever with a 10 to 20 nm tip curvature radius. We have found that in the process of enzymatic catalysis, the mean amplitude of height fluctuations in individual enzyme molecules is 1.4-fold higher than that of enzyme molecules in an inactive state. The temperature dependence of the mean amplitude of height fluctuations in cytochrome CYP102A1 has been revealed, and the maximum of this dependence has been observed at 22 °C. The proposed nanotechnology-based approach can be employed in studies of a wide variety of enzymes, which are important for the development of novel diagnostic tests and systems for pharmaceutical analysis. The approach developed in our work will favor further miniaturization of enzyme-based biosensors and the transition from traditional sensors to nanobiosensors. Full article

The complexes of negatively charged polysaccharides with lipid vesicles have been shown to have applications in medicine, bioremediation, water purification, and construction of nano-biosensors. This article presents research on the formation of these complexes based on the interactions between three types of liposomes, DOPC liposomes (which contain a lipid bilayer in the liquid-disordered (Ld) state), RAFT liposomes (which contain liquid-ordered (Lo) lipid raft domains surrounded by lipids in the Ld state) and SPH–CHL liposomes (which contain a lipid bilayer in the Lo state), and two selected anionic polysaccharides, polysialic acid (PSA) and polygalacturonic acid (PGA). The analysis was conducted using a toluidine blue (TB) probe and the absorption spectroscopy technique. In contrast to DOPC and SPH–CHL liposomes, binding of negatively charged PSA or PGA chains to RAFT liposomes induced a TB absorption maximum shift from 630 nm to 560 nm. The obtained results indicate that toluidine blue can be applied for monitoring the formation of these nano-complexes, and that the boundaries between Ld/Lo domains within membranes in RAFT liposomes can significantly enhance the binding affinity of negatively charged polysaccharides to the lipid bilayer surface. The observed metachromatic shift in TB absorption suggests that negatively charged PSA and PGA chains interact with the Ld/Lo boundaries within RAFT liposome membranes. Full article

Electrode surface microstructuring involves the engineering of the topographical features of an electrode to enhance its performance in electrochemical sensing applications. By creating controlled micro- or nano-scale patterns, the active surface area can significantly increase, which leads to improved electron transfer and enhanced sensitivity to target analytes in devices such as biosensors. Geometrical parameters such as diameter, height, pitch, and position of the patterns can be optimized to enhance sensor detection. This paper introduces an electrochemical biosensor designed to detect Moraxella catarrhalis, a respiratory pathogen affecting young children. This paper investigates the effects of the radius of micropillars on adsorption in the electrochemical biosensor using COMSOL Multiphysics (Version: 6.0). The model demonstrates that the rate of surface adsorption depends on the position of the micropillars on the electrode. The paper also presents the effects of analyte concentration on the detection current of the biosensor using Cottrell’s equation. Full article

Ovarian cancer survival depends strongly on the time of diagnosis. Detection at stage 1 must be the goal of liquid biopsies for ovarian cancer detection. We report the development and validation of graphene-based optical nanobiosensors (G-NBSs) that quantify the activities of a panel of proteases, which were selected to provide a crowd response that is specific for ovarian cancer. These G-NBSs consist of few-layer explosion graphene featuring a hydrophilic coating, which is linked to fluorescently labeled highly selective consensus sequences for the proteases of interest, as well as a fluorescent dye. The panel of G-NBSs showed statistically significant differences in protease activities when comparing localized (early-stage) ovarian cancer with both metastatic (late-stage) and healthy control groups. A hierarchical framework integrated with active learning (AL) as a prediction and analysis tool for early-stage detection of ovarian cancer was implemented, which obtained an overall accuracy score of 94.5%, with both a sensitivity and specificity of 0.94. Full article

The development of a robust and biocompatible pH-sensing platform is critical for monitoring intracellular processes and diagnosing diseases. Here, we present a smart ultrastable ratiometric fluorescence nano pH sensor based on silica-coated liposome nanoparticles (cerasome, 138.4 nm). The sensor integrates pH-sensitive dye, pyranine, within cerasome, achieving enhanced photostability, sensitivity, and biocompatibility. Its unique ratiometric design enables precise pH monitoring with minimal photobleaching and quenching, covering a linear detection range of pH 6.25–8.5. The hybrid nanoparticles exhibit high morphological stability, making them suitable for real-time intracellular pH measurement. This novel platform shows great promise for applications in cellular biology, disease diagnosis, and therapeutic monitoring, offering a versatile tool for biomedical research. Full article

Antimicrobial resistance (AMR) is a rapidly growing global concern resulting from the overuse of antibiotics in agricultural and clinical settings. The challenge is exacerbated by the lack of rapid surveillance for resistant bacteria in clinical, environmental, and food supply settings. The increasing resistance to carbapenems, an important sub-class of beta-lactam antibiotics, is a major concern in the healthcare community. Carbapenem resistance (CR) has been found in the environment and food supply chain, where it has the potential to spread to pathogens, animals, and humans through direct or indirect contact. Rapid detection for preventative and control measures should be developed. This study utilized a gold nanoparticle-based plasmonic biosensor for the parallel detection of the CR genes bla_NDM-1 and bla_OXA-1. To explore the field portability, DNA was extracted using two methods: a commercial extraction kit and a boiling method. The results were compared between the two methods using a spectrophotometer and a cellphone application for RGB values to quantify the visual results. The results showed that the boiling method of extraction was more effective than extraction with a commercial kit for this analysis. The parallel detection of unamplified genes extracted via the boiling method is novel. When combined with other portable testing equipment, the approach has the potential to be an inexpensive, rapid, and simple on-site CR gene detection protocol. Full article

Carbon quantum dots (CQDs), a new class of carbon-based nanomaterials, have emerged as nano-scaled probes with photoluminescence that have an eco-friendly and bio-compatible nature. Their cost-efficient synthesis and high photoluminescence quantum yields make them indispensable due to their application in opto-electronic devices, including biosensors, bioimaging, environmental monitoring, and light sources. This review provides intrinsic properties of CQDs such as their excitation-dependent emission, biocompatibility, and quenching properties. Diverse strategies for their easy synthesis are divided into bottom-up and top-down approaches and detailed herein. In particular, we highlight their luminescence properties, including quenching mechanisms that could even be utilized for the precise and rapid detection of biomolecules. We also discuss methodologies for the mitigation of fluorescence quenching, which is pivotal for the application of CQDs in biosensors and bioimaging. Full article

Biosensing shows promise in detecting cancer, renal disease, and other illnesses. Depending on their transducing processes, varieties of biosensors can be divided into electrochemical, optical, piezoelectric, and thermal biosensors. Advancements in material production techniques, enzyme/protein designing, and immobilization/conjugation approaches can yield novel nanoparticles with further developed functionality. Research in cutting-edge biosensing with multifunctional nanomaterials, and the advancement of practical biochip plans utilizing nano-based sensing material, are of current interest. The miniaturization of electronic devices has enabled the growth of ultracompact, compassionate, rapid, and low-cost sensing technologies. Some sensors can recognize analytes at the molecule, particle, and single biological cell levels. Nanomaterial-based sensors, which can be used for biosensing quickly and precisely, can replace toxic materials in real-time diagnostics. Many metal-based NPs and nanocomposites are favorable for biosensing. Through direct and indirect labeling, metal-oxide NPs are extensively employed in detecting metabolic disorders, such as cancer, diabetes, and kidney-disease biomarkers based on electrochemical, optical, and magnetic readouts. The present review focused on recent developments across multiple biosensing modalities using metal/metal-oxide-based NPs; in particular, we highlighted the specific advancements of biosensing of key nanomaterials like ZnO, CeO₂, and TiO₂ and their applications in disease diagnostics and environmental monitoring. For example, ZnO-based biosensors recognize uric acid, glucose, cholesterol, dopamine, and DNA; TiO₂ is utilized for SARS-CoV-19; and CeO₂ for glucose detection. Full article

Annually, the Philippines is burdened by a high number of infections and deaths due to Dengue. This disease is caused by the Dengue virus (DENV) and is transmitted from one human host to another by the female Aedes aegypti mosquito. Being a developing country, most of the high-risk areas in the Philippines are resource-limited and cannot afford equipment for detection and monitoring. Moreover, traditional clinical diagnoses of DENV infection are costly and time-consuming and require expertise. Hence, it is important to establish effective vector control and surveillance measures. In this study, we developed a DNA-based nanobiosensor for the colorimetric detection of Dengue virus serotype 2 (DENV-2) synthetic target DNA (stDNA S2) using gold nanoparticles (AuNPs). We successfully functionalized dextrin-capped gold nanoparticles with the designed DENV-2 oligonucleotide probes. The detection of the complementary stDNA S2, indicated by the pink-colored solution, was successfully performed within 15 min using 0.40 M NaCl solution. We were able to detect up to 36.14 ng/μL of stDNA S2 with some cross-reactivity observed with one non-complementary target. We believe that our study offers a basis for developing nanobiosensors for other DENV serotypes. Full article

Functionalized plasmonic nanostructure platforms are widely used for developing optical biosensors and SERS assays. In this work, we present a low-cost and scalable surface-enhanced Raman scattering (SERS) system based on an innovative optical transducer comprising gold nanoparticles (AuNPs) embedded in nano-fibrillated bacterial cellulose (BC). The AuNPs@BC composite leverages the unique nanofibrillar architecture of bacterial cellulose, which provides a high surface area, flexibility, and uniform nanoparticle distribution, enabling the formation of numerous electromagnetic “hot spots”. This structure excites localized surface plasmon resonance (LSPR), as demonstrated by a bulk sensitivity of 72 nm/RIU, and supports enhanced Raman signal amplification. The eco-friendly and disposable AuNPs@BC platform was tested for agrifood applications, focusing on the detection of thiram pesticide. The system achieved a detection limit of 0.24 ppm (1 µM), meeting the sensitivity requirements for regulatory compliance in food safety. A strong linear correlation (R² ≈ 0.99) was observed between the SERS peak intensity at 1370 cm⁻¹ and thiram concentrations, underscoring its potential for quantitative analysis. The combination of high sensitivity, reproducibility, and environmental sustainability makes the AuNPs@BC platform a promising solution for developing cost-effective, flexible, and portable sensors for pesticide monitoring and other biosensing applications. Full article