Search Results (346)

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

Pesticides are applied to promote performances in the agricultural field, sustaining crop productivity by counteracting the damages induced by pests and weeds. Under conditions of uncontrolled application, their negative influences exerted on soil, water and biodiversity mean contamination of food and impact on human health. The reactive oxygen species generation induced by pesticides impair the antioxidant protective ability. For humans, pesticides can have cytotoxic, carcinogenic, and mutagenic potential. They can be classified relying on the chemical structure or on the targeted organism. Optical sensors are based on UV-Vis absorption, fluorescence, chemiluminescence, surface plasmon resonance or Raman scattering. Based on their coloring features, nanomaterials are used in optical sensing platforms. They impart high specific surface area, small sizes, facility of surface modification by biorecognition elements (enzyme, antibody, aptamer, molecularly-imprinted polymer) and promote sensitivity and selectivity in biosensing platforms. The present paper highlights the performances of the optical sensing platforms in pesticide assay. Relevant novel applications are discussed critically, following the attempts to improve analytical features of chemical and biochemical sensors. Critical comparison of the techniques is performed in the last section. Advances in nanofabrication like the inclusion of novel nanomaterials and optimizing data interpretation by integration of algorithms can further enhance performances. Full article

Advanced oxidation processes using porphyrin-based heterogeneous catalysts hold promise for removing hazardous pollutants from wastewater. Their high visible-light absorption coefficients enable absorption of light from the solar spectrum. Moreover, their conjugated aromatic skeletons and intrinsic electronic properties facilitate the delocalization of photogenerated electrons during photodegradation. Delaying the recombination of photogenerated electron–hole pairs by introducing specific materials increases efficiency, as separated charges have more time to participate in redox reactions, boosting photocatalytic activities. However, applying these photocatalysts for wastewater treatment is challenging owing to facile agglomeration, deactivation, and recovery of the photocatalyst for reuse, which can significantly increase the overall cost. Therefore, new photocatalytic systems comprising porphyrin molecules must be developed. For this purpose, porphyrins can be conjugated to nanomaterials to create hybrid materials with photocatalytic efficiencies superior to those of free-standing starting porphyrins. Various transition metal oxides (TiO₂, ZnO, and Fe₃O₄) nanoparticles, main-group-element oxides (Al₂O₃ and SiO₂) nanoparticles, metal plasmons (silver nanoparticles), carbon-based platforms (graphene, graphene oxide, and g-C₃N₄), and polymer matrices have been used as nanostructured solid supports for the successful fabrication of porphyrin-conjugated hybrid materials. The conjugation of porphyrin molecules to solid supports improves the photocatalytic degradation activity in terms of visible-light conversion ability, recyclability, active porous sites, substrate mobility, separation of photogenerated charge species, recovery for reuse, and chemical stability, along with preventing the generation of secondary pollution. This review discusses the ongoing development of porphyrin-conjugated hybrid nanomaterials for the heterogeneous photocatalytic degradation of organic dyes, pharmaceutical pollutants, heavy metals, pesticides, and human care in water. Several important results and advancements in the field allow for a more efficient wastewater remediation process. Full article

The precise and reliable detection of milk adulterants has garnered increased scientific interest owing to the rising incidence of food fraud. Recent years have witnessed substantial advancements in optical and electrochemical biosensors for the quick, sensitive, and on-site determination of adulterants. This review thoroughly emphasizes recent developments in electrochemical biosensors, encompassing amperometric, voltammetric, impedimetric, and photoelectrochemical sensors, alongside optical biosensors such as colorimetric, fluorometric, and plasmonic systems. Significant focus is directed towards determination of critical milk adulterants, including variations in pH, urea, formaldehyde (FA), melamine (MEL), nitrates (NO₃⁻), nitrites (NO₂⁻), and sulfites (SO₃²⁻). The sensing mechanisms, functional nanomaterials, analytical efficacy, and sample-handling techniques of the described biosensors are critically examined. Moreover, key challenges regarding matrix interference, sensor stability, reproducibility, regulatory validation, and large-scalability are addressed. Ultimately, future directions towards economical, portable, wearable, and Internet of Things (IoT)-integrated biosensors for continuous dairy monitoring are discussed, highlighting the necessity for standardized validation protocols and next-generation technologies in food safety. Full article

Nanoparticle-mediated photothermal conversion exploits the unique light-to-heat transduction properties of engineered nanomaterials to address challenges in energy, water, and healthcare. This review first examines fundamental mechanisms—localized surface plasmon resonance (LSPR) in plasmonic metals and broadband interband transitions in semiconductors—demonstrating how tailored nanoparticle compositions can achieve >96% absorption across 250–2500 nm and photothermal efficiencies exceeding 98% under one-sun illumination (1000 W·m⁻², AM 1.5G). Next, we highlight advances in solar steam generation and desalination: floating photothermal receivers on carbonized wood or hydrogels reach >95% efficiency in solar-to-vapor conversion and >2 kg·m⁻²·h⁻¹ evaporation rates; three-dimensional architectures recapture diffuse flux and ambient heat; and full-spectrum nanofluids (LaB₆, Au colloids) extend photothermal harvesting into portable, scalable designs. We then survey photothermal-enhanced thermal energy storage: metal-oxide–paraffin composites, core–shell phase-change material (PCM) nanocapsules, and MXene– polyethylene glycol—PEG—aerogels deliver >85% solar charging efficiencies, reduce supercooling, and improve thermal conductivity. In biomedicine, gold nanoshells, nanorods, and transition-metal dichalcogenide (TMDC) nanosheets enable deep-tissue photothermal therapy (PTT) with imaging guidance, achieving >94% tumor ablation in preclinical and pilot clinical studies. Multifunctional constructs combine PTT with chemotherapy, immunotherapy, or gene regulation, yielding synergistic tumor eradication and durable immune responses. Finally, we explore emerging opto-thermal nanobiosystems—light-triggered gene silencing in microalgae and poly(N-isopropylacrylamide) (PNIPAM)–gold nanoparticle (AuNP) membranes for microfluidic photothermal filtration and control—demonstrating how nanoscale heating enables remote, reversible biological and fluidic functions. We conclude by discussing challenges in scalable nanoparticle synthesis, stability, and integration, and outline future directions: multicomponent high-entropy alloys, modular photothermal–PCM devices, and opto-thermal control in synthetic biology. These interdisciplinary innovations promise sustainable solutions for global energy, water, and healthcare demands. Full article

Widespread antibiotic residues in aquatic environments pose escalating threats to ecological stability and human health, highlighting the urgent demand for effective remediation strategies. In recent years, photocatalytic technology based on advanced nanomaterials has emerged as a sustainable and efficient strategy for antibiotic degradation, enabling the effective utilization of solar energy for environmental remediation. This review provides an in-depth discussion of six representative categories of photocatalytic nanomaterials that have demonstrated remarkable performance in antibiotic degradation, including metal oxide-based systems with defect engineering and hollow architectures, bismuth-based semiconductors with narrow band gaps and heterojunction designs, silver-based plasmonic composites with enhanced light harvesting, metal–organic frameworks (MOFs) featuring tunable porosity and hybrid interfaces, carbon-based materials such as g-C₃N₄ and biochar that facilitate charge transfer and adsorption, and emerging MXene–semiconductor hybrids exhibiting exceptional conductivity and interfacial activity. The photocatalytic performance of these nanomaterials is compared in terms of degradation efficiency, recyclability, and visible-light response to evaluate their suitability for antibiotic degradation. Beyond parent compound removal, we emphasize transformation products, mineralization, and post-treatment toxicity evolution as critical metrics for assessing true detoxification and environmental risk. In addition, the incorporation of artificial intelligence into photocatalyst design, mechanistic modeling, and process optimization is highlighted as a promising direction for accelerating material innovation and advancing toward scalable, safe, and sustainable photocatalytic applications. Full article