Search Results (351)

Surface-enhanced Raman spectroscopy (SERS) has emerged as a transformative tool in biomedical diagnostics, offering a highly sensitive and non-invasive method for detecting molecular biomarkers at exceptionally low concentrations. This approach takes advantage of the plasmonic characteristics of customized metallic nanostructures that produce intense localized electromagnetic fields via localized surface plasmon resonance and facilitate electron transfer reactions that notoriously enhance the intrinsically weak Raman scattering signals of molecular entities which reside on or next to their surfaces. SERS-based assays have shown remarkable potential in detecting cancer biomarkers, circulating tumor DNA (ctDNA), and proteins at early stages, enabling timely and targeted intervention. Additionally, the combination of SERS with AI-driven data analysis has facilitated real-time diagnostics, enhancing the precision and efficiency of point-of-care testing. Despite its promising capabilities, challenges such as substrate fouling, signal degradation, and the need for better biocompatibility remain. Nevertheless, ongoing research in substrate development, coupled with advances in AI, positions SERS as a leading technology for future diagnostic tools. This paper explores the current state of SERS in biomedical applications, highlighting its potential to revolutionize diagnostics and personalized medicine while addressing the existing limitations and future research directions. Full article

Raman spectroscopy (SERS) has emerged as a powerful analytical technique, offering molecular fingerprint specificity and ultrasensitive detection of cardiac biomarkers. Recent advances in plasmonic nanostructures, surface functionalization strategies, and flexible sensing platforms have significantly improved the analytical performance of SERS-based biosensors. In parallel, the integration of artificial intelligence (AI) and machine learning has enabled robust interpretation of complex spectral datasets, facilitating automated biomarker classification and improved diagnostic accuracy in heterogeneous biological environments. Despite these advances, the field remains fragmented, with limited integration between nanomaterial design, biomarker selection, and data-driven analysis, and persistent challenges related to reproducibility, standardization, and clinical validation. This review provides a comprehensive and critical synthesis of AI-assisted SERS platforms for cardiovascular diagnostics, integrating advances in plasmonic materials, biomolecular recognition, and intelligent spectral analysis within a unified framework. It further examines key translational barriers, including data variability, model interpretability, and scalability, and outlines future directions for developing standardized, edge-deployable, and clinically validated SERS-AI systems. Full article

Antibiotic resistance and biofilm-associated infections require sustainable antimicrobial platforms that combine efficacy with biocompatibility. Fermented matrices are attractive for green nanomaterial production because they provide reducing metabolites and surface-active capping compounds. Rooibos kombucha is a polyphenol-rich fermentation system with potential to serve as a biosynthetic matrix for silver nanoparticles (AgNPs). The present work aimed to develop a rooibos kombucha-enabled platform for the green biosynthesis of phytochemical-capped silver nanoparticles, AgNPs-K, and evaluate their antibacterial, antibiofilm, and in vivo activity. Rooibos kombucha was fermented for 14 days and profiled by liquid chromatography–tandem mass spectrometry (LC–MS/MS). AgNPs-K were generated using kombucha extract and AgNO₃, purified, and characterized by ultraviolet–visible spectroscopy (UV–Vis), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), and nanoparticle tracking analysis. Antibacterial activity against eight Gram-positive and Gram-negative reference pathogens was assessed by EUCAST-based microdilution and time-kill assays. Biofilm inhibition was measured by the crystal violet assay. In vivo toxicity and therapeutic efficacy were evaluated in Galleria mellonella larvae. AgNP formation was confirmed by a surface plasmon resonance (SPR) peak at 415 nm. TEM showed predominantly spherical nanoparticles with a main size range of 20–30 nm, a hydrodynamic diameter of 98 nm, and a zeta potential of −14.62 ± 0.04 mV. AgNPs-K showed overlapping minimum inhibitory concentration and minimum bactericidal concentration values of 1.14 µg/mL for Gram-positive species and 1.33 µg/mL for Gram-negative species. Time-kill assays showed rapid bactericidal activity after threshold concentrations were reached, with sustained suppression at 24 h. Biofilm formation was abolished at 40 µg/mL and strongly reduced at lower concentrations. AgNPs-K were non-toxic up to 400 µg/mL and improved survival in six of seven infection models. Fermented rooibos kombucha functions as an effective biosynthetic matrix for the green production of phytochemical-capped AgNPs. The resulting nanoparticles combine low-dose antibacterial and antibiofilm activity with favorable in vivo tolerability and efficacy, supporting fermentation-enabled nanobiotechnology strategies against biofilm-associated infection. Full article

The field of infrared (IR) photodetection is undergoing rapid development through the emergence of solution-processable nanoparticle (NP)-based materials and fabrication strategies. This review critically examines recent advances in fabrication approaches for NP-based IR detectors, emphasizing the relationship between synthesis, surface engineering, deposition processes, and device architecture in determining detector performance. Representative material platforms are discussed, including colloidal quantum dots (CQDs) such as PbS and HgTe, which enable tunable operation from the near-infrared (NIR) and short-wave infrared (SWIR) to selected mid-wave (MWIR), long-wave (LWIR), and emerging very-long-wave infrared (VLWIR) regimes depending on material composition and operating conditions. Further platforms including plasmonic metal NPs, black phosphorus, and topological nanomaterials are evaluated for their unique mechanisms of optical enhancement and broadband response. Fabrication approaches including continuous-flow synthesis, ligand exchange, blade coating, inkjet printing, electrophoretic deposition, and other scalable solution-processing methods are analyzed with respect to their influence on film quality, charge transport, interface engineering, and integration compatibility. The review further compares major device architectures, including photoconductors, photodiodes, plasmonic absorbers, and phototransistors, using key performance metrics such as specific detectivity (D*), responsivity (R), response speed, and operating temperature, while emphasizing the importance of measurement conditions in cross-platform comparisons. Critical challenges including dark-current generation, 1/f noise, transport limitations associated with ligand chemistry, environmental instability of narrow-bandgap materials, manufacturability constraints, and toxicity considerations are also discussed. Emerging directions such as neuromorphic sensing, CMOS-compatible integration, and sustainable lead-free nanomaterials are highlighted. By linking nanoscale material design and fabrication processes to device-level performance, this review provides a framework for advancing NP-based IR technologies toward scalable and application-relevant sensing systems. Full article

Nanomaterial-based biosensors have advanced analytical methodologies by enhancing signal transduction, interfacial reactivity, and molecular recognition across diverse sensing platforms. In parallel, the diversity of nanomaterial compositions, architectures, and interfacial designs has expanded the range of available sensing strategies and performance outcomes. This review addresses limitations through a structure–property–function framework that links nanomaterial characteristics to sensing behavior, performance determinants, and application-specific requirements. Within this framework, nanomaterials are classified according to their dominant functional roles in biosensing, including plasmonic, electroactive, fluorescent and quantum-confined, porous, and hybrid architectures. The influence of morphology, surface chemistry, conductivity, and interfacial design on electrochemical, optical, and hybrid transduction mechanisms is critically examined, and key performance parameters, including sensitivity, selectivity, limit of detection, response time, stability, and reproducibility, are discussed in relation to material properties and sensing configuration. Recent advances in clinical biomarker detection, pathogen and nucleic acid analysis, and environmental and food safety monitoring are also evaluated to illustrate how nanomaterial design is tailored to different analytical contexts. Current limitations related to reproducibility, interface engineering, long-term stability, and scalable device integration are highlighted, together with future directions for the rational development of robust and application-oriented biosensor platforms. Full article

Background/Objectives: Silver nanoparticles (AgNPs) are highly valuable nanomaterials due to their unique optical and physicochemical properties. AgNPs have a lot of promise as contrast-enhancing and diagnostic agents in image-guided treatment. With a focus on their incorporation into image-guided and theranostic approaches, this narrative review attempts to assess the current function of AgNPs in imaging diagnostics. Methods: Using major scientific databases, such as PubMed, Web of Science, and Scopus, a narrative literature review has been conducted with an emphasis on recent preclinical and experimental research examining AgNP-based systems for diagnostic imaging applications. The design of the NPs, surface functionalization, imaging modality, and diagnostic performance of the evaluated studies were analyzed. Results: Due to their surface plasmon resonance and tunable physicochemical properties, AgNPs show great promise in a variety of imaging techniques, such as optical imaging, computed tomography (CT), and multimodal platforms, according to the reviewed literature. Functionalized AgNPs emerged as agents in image-guided therapy due to their improved target selectivity, enhanced imaging contrast, and signal amplification in tissues. Conclusions: AgNPs are appealing nanoscale platforms for image-guided methods and imaging diagnostics. Despite their encouraging preclinical results, some key issues, such as toxicity, biocompatibility, and clinical translation, remain critical. AgNP-based therapeutic and diagnostic systems will need to overcome these constraints in the future. Full article

Structurally complex plasmonic nanoarchitectures represent an emerging class of nanomaterials with properties that extend beyond those of conventional spherical nanoparticles. Their distinctive structural motifs generate dense near field electromagnetic hot spots, expand interfacial surface area, and create biophysical environments at the nano–bio interface that can actively engage cellular signaling networks relevant to neural regeneration and aging. Despite growing interest in these platforms, a systematic, omics-guided synthesis that links nanoparticle structural features to transcriptomic programs and regenerative outcomes has been lacking. In this review, we summarize recent advances in high complexity plasmonic nanoparticle engineering and integrate published omics-based evidence of their cellular effects, organizing the discussion. Across these studies, transcriptomic analyses of nanoparticle treated neural systems consistently highlight three convergent biological themes: mitigation of oxidative stress and activation of antioxidant pathways, suppression of neuroinflammatory signaling, and induction of neuronal developmental and plasticity programs. Collectively, the omics-guided findings synthesized here suggest that structural complexity in plasmonic nanoarchitectures is not merely a synthetic achievement but a tunable determinant of cellular state, with important implications for the rational design of regenerative nanomedicines targeting neurodegenerative diseases and age-related neuronal decline. Full article

The high morbidity and mortality of cancer pose a severe challenge to human health. Traditional diagnostic and therapeutic strategies still exhibit obvious limitations in early diagnostic sensitivity, therapeutic precision, and real-time monitoring of treatment efficacy. The development of nanotechnology has provided novel solutions for precision cancer theranostics. Among nanomaterials, gold nanoparticles (AuNPs) have become a research hotspot in tumor nanomedicine due to their tunable size and morphology, excellent localized surface plasmon resonance (LSPR) effect, and favorable biocompatibility. However, despite encouraging preclinical outcomes, several challenges hinder their clinical translation, including an incomplete understanding of long-term toxicity, complex in vivo biological interactions, the lack of standardized evaluation protocols, and regulatory uncertainties and manufacturing reproducibility issues. This paper systematically reviews the physicochemical and biological mechanisms of AuNPs in cancer theranostics, and summarizes the latest research advances of AuNPs in cancer detection and diagnosis (including biomarker detection and multimodal imaging) as well as in therapeutic fields, covering photothermal therapy (PTT), photodynamic therapy (PDT), radiosensitization, targeted drug and nucleic acid delivery, and immunotherapy-assisted strategies. Furthermore, we discuss the development of intelligent and stimuli-responsive theranostic nanoplatforms based on AuNPs, and outline their future prospects in precision medicine and personalized cancer therapy, with particular emphasis on the requirements for clinical translation, including safety evaluation, large-scale production, and regulatory approval pathways. Full article

Metal-enhanced fluorescence (MEF) has found widespread application in biomedical sensing and in vivo tissue imaging systems. To enhance MEF efficiency, it is necessary to optimize the interaction between the metal nanoparticle plasmon and the fluorophore molecule. The size and shape of the nanoparticle, the nanoscale gap between the fluorescent molecule and the nanoparticle, and the excitation wavelength are critical parameters. In this study, we propose a model for a more complete and accurate description of the processes of molecular excitation and generation of the fluorescence spectral response, introducing a new concept of effective properties for the field enhancement factor, quantum yield, and fluorescence enhancement factor. The influence of the spectral properties of both the nanostructure plasmon and the fluorophore molecule on the optimal tuning of fluorescent complexes is studied. Particular attention is paid to the analysis of the spectral properties of plasmon resonance and calculations of the near-field intensity enhancement of the plasmonic nanostructure’s excitation field. Numerical results for optimizing the MEF of fluorescent complexes based on TagRFP and gold (silver) nanorod composites are presented. The advantages of the proposed model for the optimal design of new nanomaterials with unique fluorescent properties are discussed. Full article

Catalytic materials are central to the advancement of hydrogen generation technologies, playing a pivotal role in enabling sustainable, carbon-neutral energy systems. Hydrogen can be produced via electrochemical water splitting, thermochemical reforming, or photocatalysis—each imposing unique performance requirements on catalysts in terms of activity, selectivity, stability, and efficiency. While traditional noble metals (e.g., platinum, ruthenium, iridium) provide benchmark catalytic activity, their widespread use is hindered by scarcity, high cost, and limited long-term durability. Consequently, researchers have increasingly focused on earth-abundant alternatives such as transition metals (Ni, Co, Fe, Mo), alloys, metal oxides, carbides, sulfides, nitrides, and carbon-based systems. Among these, two-dimensional materials, particularly the MXene family, have attracted significant attention due to their metallic conductivity, layered structure, and tunable surface chemistry. These features enable rapid charge transfer and abundant active sites, making MXenes and related nanostructured catalysts promising for both the Hydrogen Evolution Reaction (HER) and Oxygen Evolution Reaction (OER) across a wide range of electrochemical conditions. Parallel efforts have integrated novel semiconductors, plasmonic nanomaterials, and hybrid heterostructures to improve the efficiency of solar-to-hydrogen energy conversion. This paper reviews the main types of catalytic materials used in hydrogen production, explains their design strategies and structure–performance relationships, and discusses key engineering challenges such as integrating renewable energy sources, scaling up manufacturing, and ensuring long-term durability in real-world systems. Future research goals are also highlighted, including the development of affordable non-noble catalysts, enhancing catalyst stability through surface and defect engineering, and coupling hydrogen production with circular economy principles, all of which are essential to making hydrogen generation more efficient, scalable, and cost-effective as the world transitions to clean and sustainable energy. Full article

Hybrid nanomaterials that integrate surface functionality, colloidal stability, and efficient electron-transfer pathways are highly attractive for improving electrochemical sensing performance. Herein, we report the fabrication and evaluation of polyethyleneimine-functionalized gallium nitride nanoparticles (GaN) decorated with gold nanoparticles (GaN-PEI-Au) as a tunable electrode modifier for enhanced differential pulse voltammetry (DPV) detection of erythromycin. Branched polyethyleneimine was employed as a multifunctional interfacial layer to stabilize GaN dispersions, introduce amine-rich surface chemistry, and enable in situ gold nanoparticle formation at the GaN-PEI. The optimized GaN-PEI-Au material exhibited high colloidal stability, a characteristic Au localized surface plasmon resonance in the ~520–525 nm range, and well-defined Au nanoparticles attached to the GaN surface. When applied as an electrode coating, GaN-PEI-Au significantly enhanced the erythromycin oxidation response compared to bare Au and GaN-PEI interfaces, consistent with synergistic increases in electroactive surface area and interfacial charge-transfer efficiency. Under optimized DPV conditions, GaN-PEI-Au-modified electrodes enabled quantitative erythromycin determination with a linear range of 5 nM–2 µM (R² = 0.990), sensitivity of 1.32 × 10⁻³ µA nM⁻¹, and a limit of detection of 52.5 nM, while maintaining stable baseline behavior during repeated scans. The reported GaN-PEI-Au nanocomposites represent a robust platform for sensitive electrochemical detection of pharmaceutical compounds. Full article

The synthesis of continuous non-linear metal nanostructures at the micro and nanoscale remains a challenging frontier in nanotechnology due to inherent synthetic constraints. This study introduces an innovative chemical methodology for fabricating continuous rings and diverse geometries via the chemical fusion of gold nanorods (AuNRs) on a solid substrate. Initially, aqueous solutions of cetyltrimethylammonium bromide (CTAB)-coated AuNRs were deposited and dried on a solid substrate, resulting in the self-assembly of ring-like arrays. Subsequent chemical growth of the AuNRs in all dimensions was achieved using an aqueous solution of Au(I)/CTAB/Ascorbic Acid (AA), enabling their fusion into continuous structures. This approach permits the formation of arbitrary shapes by pre-arranging AuNRs, thereby opening new avenues for the exploration of non-linear nanostructures with potentially novel plasmonic and electronic properties. The capability to engineer such complex nanostructures is pivotal for advancing fields such as photonics, electronics, and sensing, where the unique optical and electronic properties of gold nanostructures can be exploited for cutting-edge applications. Furthermore, this technique shows a significant promise for the fabrication of various micro- and nanodevices and the seamless interconnection of components in integrated electronic circuits, potentially leading to more efficient and miniaturized electronic systems. The broader implications of this research are significant, offering a potential pathway to the development of nanomaterials and devices that could benefit various industries and technological processes. Full article

Fluorescence remains a foundational optical phenomenon underpinning applications in sensing, imaging, diagnostics, and catalysis. Among the strategies developed to modulate fluorescence, coupling fluorophores with plasmonic metals has emerged as a powerful route for both enhancement and quenching. The collective excitation and decay of surface plasmons can profoundly alter fluorophore excitation rates, radiative pathways, and emission efficiencies. This review provides a mechanistic and historical synthesis of metal–fluorophore interactions, unifying enhancement and quenching phenomena under the term Metal Manipulated Fluorescence (MMF). We summarize the fundamental principles of fluorescence and plasmon resonance, discuss theoretical and computational approaches for predicting metal–fluorophore coupling, and critically examine recent advances in plasmonic nanostructure synthesis that enable precise control over fluorophore behaviour. By integrating experimental observations with theoretical models, we highlight the opportunities and limitations of current MMF strategies and outline future directions in materials design, synthesis methodologies, and predictive modelling for next-generation optical and optoelectronic technologies. Full article

The accurate monitoring and dynamic analysis of metal ions are of considerable practical significance in environmental toxicology and life sciences. Colorimetric analysis and surface-enhanced Raman scattering (SERS) sensing technologies, utilizing the aggregation effect of gold and silver nanoparticles (Au/Ag NPs), have emerged as prominent methods for rapid metal ion detection. While sharing a common plasmonic basis, these two techniques serve distinct yet complementary analytical roles: colorimetric assays offer rapid, instrument-free visual screening ideal for point-of-care testing (POCT), whereas SERS provides superior sensitivity and structural fingerprinting for precise quantification in complex matrices. Furthermore, the synergistic integration of these modalities facilitates the development of dual-mode sensing platforms, enabling mutual signal verification for enhanced reliability. This article evaluates contemporary optical sensing methodologies utilizing aggregation effects and their advancements in the detection of diverse metal ions. It comprehensively outlines methodological advancements from nanomaterial fabrication to signal transduction, encompassing approaches such as biomass-mediated green synthesis and functionalization, targeted surface ligand engineering, digital readout systems utilizing intelligent algorithms, and multimodal synergistic sensing. Recent studies demonstrate that these techniques have attained trace-level identification of target ions regarding analytical efficacy, with detection limits generally conforming to or beyond applicable environmental and health safety regulations. Moreover, pertinent research has enhanced detection linear ranges, anti-interference properties, and adaptability for POCT, validating the usefulness and developmental prospects of this technology for analysis in complicated matrices. Full article

Gold nanorods (AuNRs) were synthesized and optimized with the aim of obtaining strongly hydrophilic nanomaterials, suitable as a drug delivery system (DDS) for copper-based drugs. After careful purification, AuNRs were characterized by ultraviolet–visible–near-infrared spectroscopy (UV–Vis–NIR), showing two typical localized surface plasmon resonance (LSPR) bands in the range 550–750 nm. Fourier Transform Infrared (FT-IR) and high-resolution X-ray photoelectron (HR-XPS) spectroscopies verified the surface functionalization. Transmission electron microscopy (TEM) showed AuNRs with regular shape and size, with an aspect ratio (AR) of 2.6. Dynamic Light Scattering (DLS) measurements confirmed the size and the stability in water for up to 3 months. The AuNRs were conjugated with copper(I) drugs, i.e., [Cu(PTA)₄]BF₄ (PTA = 1,3,5-triaza-7-phosphadamantane). The drug loading procedures and efficiency were optimized, and the best loading was η (%) = 50 ± 7%. The non-covalent interactions of the Cu(I) complex with the AuNRs were studied by means of UV–Vis–NIR, ζ-potential, HR-TEM, FT-IR, synchrotron radiation-induced X-ray photoelectron (SR-XPS), and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy measurements. The MTT assay performed on Vero E6 cells showed that AuNRs and AuNR-Cu(I) conjugates had no significant effect on cell viability, being biocompatible, causing a reduction in cell viability only after prolonged exposure. Full article