Calculated absorption and scattering properties of gold nanoparticles of different size, shape, and composition: applications in biological imaging and biomedicine

A multi-modal embolic gel system for long-term fluorescence imaging and photothermal therapy

Gel embolic agents are increasingly recognized for their versatility in minimally invasive vascular interventions. However, their application in real-time imaging, post-operative monitoring, and thermal treatment remains underexplored. In this study, we present a novel transcatheter injectable nanoclay-alginate (NCA) gel embolic agent integrated with indocyanine green (ICG) for dual fluorescence imaging and thermal ablation. The NCA/ICG embolic gel exhibits excellent shear-thinning properties, transcatheter injectability, and mechanical stability. Furthermore, the mechanism to enhance fluorescence for real-time imaging enhancement and extended post-operative monitoring was discussed. A 28-day fluorescence persistence shows the NCA/ICG gel's long-lasting fluorescent signal, which was significantly stronger and longer compared to current clinically used ICG aqueous solution. Furthermore, the gel can effectively convert near-infrared (NIR) laser energy into heat for potential photothermal therapy. The biocompatibility and enhanced antibacterial properties further highlight the potential clinical benefits of this embolic agent as a multifunctional agent for vascular embolization.

A Sensitive SERS Sensor for Simultaneous Detection of Two Potential Biomarkers of Alzheimer's Disease: AChE and MAO-B

Monoamine oxidase B (MAO-B) and acetylcholinesterase (AChE) are potential biomarkers for Alzheimer's disease (AD). However, few methods exist to detect both AChE and MAO-B simultaneously. In this study, we developed a SERS sensor for the simultaneous detection of AChE and MAO-B based on the one-pot reaction system, which provided more valuable information for early AD diagnosis. Au NPs modified with Raman reporter 4-aminothiophenol (AuPATP NPs) were attached to Cu-BTC via Schiff's base reaction (AuPATP NPs@Cu-BTC), resulting in great Raman intensity. Phenethylamine (PEA), a substrate of MAO-B, competed with AuPATP NPs for binding to Cu-BTC, reducing the intensity of the Raman signal. Additionally, two PATP molecules on free Au NPs coupled to DMAB due to the catalysis of Cu2+ in Cu-BTC, transforming AuPATP NPs into AuDMAB NPs and generating three new Raman peaks. TCh, the catalytic product of AChE, was chelated with Cu2+, so the coupling efficiency of PATP has been decreased, and the conversion of AuPATP NPs to AuDMAB NPs has been prevented. Based on the one-pot reaction system, both MAO-B and AChE can be detected by Raman signals from precipitated AuPATP NPs@Cu-BTC and supernatant AuDMAB NPs after centrifugation. The detection limits were 2.3 × 10-3 μg mL-1 for MAO-B and 1.6 × 10-3 U L-1 for AChE. We successfully detected MAO-B and AChE in serum with recoveries ranging from 100.0 to 113.7% for MAO-B and 93.6 to 120% for AChE. This manuscript presents a novel method for the simultaneous detection of MAO-B and AChE, showing great potential for early AD diagnosis.

Integrative plasmonics: optical multi-effects and acousto-electric-thermal fusion for biosensing, energy conversion, and photonic circuits

Surface plasmons, a unique optical phenomenon arising at the interface between metals and dielectrics, have garnered significant interest across fields such as biochemistry, materials science, energy, optics, and nanotechnology. Recently, plasmonics is evolving from a focus on "classical plasmonics," which emphasizes fundamental effects and applications, to "integrative plasmonics," which explores the integration of plasmonics with multidisciplinary technologies. This review explores this evolution, summarizing key developments in this technological shift and offering a timely discussion on the fusion mechanisms, strategies, and applications. First, we examine the integration mechanisms of plasmons within the realm of optics, detailing how fundamental plasmonic effects give rise to optical multi-effects, such as plasmon-phonon coupling, nonlinear optical effects, electromagnetically induced transparency, chirality, nanocavity resonance, and waveguides. Next, we highlight strategies for integrating plasmons with technologies beyond optics, analyzing the processes and benefits of combining plasmonics with acoustics, electronics, and thermonics, including comprehensive plasmonic-electric-acousto-thermal integration. We then review cutting-edge applications in biochemistry (molecular diagnostics), energy (harvesting and catalysis), and informatics (photonic integrated circuits). These applications involve surface-enhanced Raman scattering (SERS), surface-enhanced infrared absorption (SEIRA), surface-enhanced fluorescence (SEF), chirality, nanotweezers, photoacoustic imaging, perovskite solar cells, photocatalysis, photothermal therapy, and triboelectric nanogenerators (TENGs). Finally, we conclude with a forward-looking perspective on the challenges and future of integrative plasmonics, considering advances in mechanisms (quantum effects, spintronics, and topology), materials (Dirac semimetals and hydrogels), technologies (machine learning, edge computing, in-sensor computing, and neuroengineering), and emerging applications (5G, 6G, virtual reality, and point-of-care testing).

Next generation gold nanomaterials for photoacoustic imaging

Photoacoustic (PA) imaging integrates ultrasound with the molecular contrast afforded by optical imaging, enabling noninvasive, real-time visualization of tissue structures and contrasts. Gold nanoparticles (GNPs) have been extensively studied as contrast agents for PA imaging due to their strong optical absorption derived from localized surface plasmon resonance, particularly when engineered to absorb in the near-infrared (NIR) region to enhance tissue penetration. However, the use of conventional anisotropic nanoparticles that absorb the NIR wavelengths is limited by their poor photostability under pulsed lasing conditions, which restricts their applicability in longitudinal in vivo imaging studies. This review first outlines the fundamental principles of PA imaging and introduces conventional GNP-based contrast agents, emphasizing their applications and inherent limitations. Subsequently, recent advances in GNP engineering are discussed, with particular focus on strategies to improve photostability, and a future perspective on the development of GNP-based PA contrast agents is provided.

AI-Assisted Plasmonic Diagnostics Platform for Osteoarthritis and Rheumatoid Arthritis With Biomarker Quantification Using Mathematical Models

Osteoarthritis (OA) and rheumatoid arthritis (RA) are major causes of functional impairment, disability, and chronic pain, leading to a substantial rise in healthcare costs. Despite differences in pathophysiology, these diseases share overlapping features that complicate diagnosis, necessitating early, more accurate, and cost-effective diagnostic tools. This study introduces an innovative plasmonic diagnostics platform for rapid and accurate label-free diagnosis of OA and RA. The sensing platform utilizes a highly dense urchin-like gold nanoarchitecture (UGN), which enhances the surface plasmonic area to significantly amplify the Raman signal. The feasibility of the developed platform for arthritis diagnosis is demonstrated by analyzing the synovial fluid (SVF) of patients. Assisted by a machine learning model, Raman signals of OA and RA groups are successfully classified with high clinical sensitivity and specificity. Metabolic biomarkers are further investigated using mathematical models of combined Pearson correlation coefficient (PCC) and non-negative matrix factorization (NMF), suggesting valuable insights for arthritis biomarker quantification. In addition, RA severity is studied using the sensing platform by classifying results from the hematology test, achieving successful stage discrimination. This platform offers a versatile, affordable, and scalable in-clinic arthritis diagnostic solution with potential applications in diagnosing and monitoring other diseases through biofluid analysis.

Rational design to improve the detection sensitivity of sandwich-type lateral flow immunoassays

This study presents two strategies to improve the detection sensitivity of the gold nanoparticle (Au NP)-based sandwich-type lateral flow immunoassay (LFIA) using the typical human chorionic gonadotropin (hCG) LFIA as the model. One efficient way is to adjust the size of Au NPs used as the label in the LFIA. Four kinds of Au NPs with different sizes (80, 110, 130, and 160 nm) were synthesized using a seed-mediated growth method, and the influence of nanoparticle size on the detection sensitivity of hCG was investigated. The results revealed that 110 nm Au NPs offered the highest detection sensitivity. Under the optimized conditions, the limit of detection (LOD) for hCG protein using Au NPs with a diameter around 110 nm as the signal probe was 5 mIU mL-1. Another powerful strategy discovered accidentally involves the introduction of an additional glass cellulose pad on the MAX-line label. The MAX-line label, which features an adhesive backing and a marked line indicating the maximum sample volume, is assembled on the test strip covering the sample pad and conjugate pad. We found that the introduction of an additional glass cellulose pad with a length of 6 mm on the MAX-line label could achieve a visual LOD of 1 mIU mL-1 for the detection of hCG. We assume that the improvement in detection sensitivity may be attributed to the increased sample carrying capacity and the extended flow time of gold nanoprobes, as the gold probes may diffuse from the conjugate pad into the enhancement pad upon rehydration. The developed LFIA also exhibited good reproducibility and stability. We believe that the developed strategies, particularly the approach of adding an enhancement pad on the MAX-line label, will serve as a general method applicable to other types of LFIAs to improve the sensitivity of target analytes.

Interactions of metal-based nanozymes with aptamers, from the design of nanozyme to its application in aptasensor: Advances and perspectives

Nanozymes, characterized by enzyme-like activity, have been extensively used in quantitative analysis and rapid detection due to their small size, batch fabrication, and ease of modification. Researchers have combined aptamers, an emerging molecular probe, with nanozymes for biosensing to address the limited reaction specificity of nanozymes. Nanozyme aptasensors are currently experiencing significant growth, offering a promising solution to the lack of rapid detection methods across various fields. Unlike traditional nanozyme research, the development of nanozyme aptasensors is challenging as it requires the design of highly active nanozymes as well as the establishment of efficient and agile interactions between aptamers and nanozymes. Therefore, this review summarizes the active species and catalytic mechanisms of various nanozymes along with classical design options, discussing the future development of nanozyme aptasensors. It is anticipated that this review will inspire researchers in this domain, leading to the design of more enzymatically active nanozymes and advanced nanozyme aptasensors.

Self-Assembled Short Peptide Amphiphile-Gold Nanostructures: A Novel Approach for Bacterial Infection Treatment

This study presents a simple and effective strategy for synthesizing biocompatible hybrid nanostructures composed of short peptide amphiphiles (sPA) and gold nanoparticles (AuNPs) for bacterial infection control. The self-assembling sPA molecules form stable β-sheet structures, which are further enhanced upon the addition of gold ions (Au(III)) and brief sunlight exposure, leading to the formation of functional AuNP-sPA nanostructures. Comprehensive spectroscopic and microscopic characterization confirms the successful integration of AuNPs with sPA, resulting in stable nanomaterials with potent antibacterial properties. The AuNP-sPA conjugates exhibit superior antibacterial activity against Gram-negative bacteria, including Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa with a high bacterial selectivity and biocompatibility with minimal cytotoxicity, reinforcing their therapeutic potential. These findings highlight AuNP-sPA nanostructures as promising alternatives to conventional antibiotics for targeted bacterial infection treatment.

Encapsulation of Citrate-Capped Gold Nanoparticles and Aqueous Solutions: Photophysical and Nonlinear Optical Properties and Elastic Scattering

The nonlinear absorption coefficient (β) and nonlinear refractive index (n2) of citrate-capped gold nanoparticles (CC-AuNPs) encapsulated and stabilized within a composition of water, n-heptane, and anionic AOT surfactant were studied by z-scan technique which includes a laser with a wavelength of 532nm and a power of 80mW. Encapsulation of AuNPs (Cap-CC-AuNPs) consists of aqueous droplets uniformly dispersed in the continuous phase of n-heptane, which enables the effective Cap-CC-AuNPs that exhibited significant nonlinear absorption despite their lower concentration, attributed to the reduced dielectric constant of the bulk medium. The aggregation of CC-AuNPs in aqueous solutions, which is the result of the increase of ions, has increased the value of β and elastic scattering. While, in the water-ethanol binary mixture, even with low aggregation along with the reduction of light scattering, the β value was enhanced with a reduction of the dielectric constant of the solution. The source of increase in nonlinear optical properties and elastic scattering of gold nanoparticles in solutions is increase in polarizability. Quantum perturbation theory was employed to calculate the dipole moment of AuNPs, it is distinguished that the ground state dipole moment of AuNPs increase with encapsulation. Cap-CC-AuNPs can serve as a photosensitizer in photodynamic therapy or other optical devices.

Open-source 3D active sample stabilization for fluorescence microscopy

Super-resolution microscopy has enabled imaging at nanometer-scale resolution. However, achieving this level of detail without introducing artifacts that could mislead data interpretation requires maintaining sample stability throughout the entire imaging acquisition. This process can range from a few seconds to several hours, particularly when combining live-cell imaging with super-resolution techniques. Here, we present a three-dimensional active sample stabilization system based on real-time tracking of fiducial markers. To ensure broad accessibility, the system is designed using readily available off-the-shelf optical and photonic components. Additionally, the accompanying software is open source and written in Python, facilitating adoption and customization by the community. We achieve a standard deviation of the sample movement within 1 nm in both the lateral and axial directions for a duration in the range of hours. Our approach allows easy integration into existing microscopes, not only making prolonged super-resolution microscopy more accessible but also allowing confocal and widefield live-cell imaging experiments spanning hours or even days.

The develop of persistent luminescence nanoparticles with excellent performances in cancer targeted bioimaging and killing: a review

The use of fluorescent nanomaterials in tumor imaging and treatment effectively avoids the original limitations of traditional tumor clinical diagnostic methods. The PLNPs emitted persistent luminescence after the end of excitation light. Owing to their superior optical properties, such as a reduced laser irradiation dose, spontaneous fluorescence interference elimination, and near-infrared imaging, PLNPs show great promise in tumor imaging. Moreover, they also achieve excellent anti-tumor therapeutic effects through surface modification and drug delivery. However, their relatively large size and limited surface modification capacity limit their ability to kill tumors effectively enough for clinical applications. Thus, this article reviews the synthesis and modification of PLNPs and the research progress in targeted tumor imaging and tumor killing. We also discuss the challenges and prospects of their future applications in these fields. This review has value for accelerating the design of PLNPs based platform for cancer diagnosis and treatment.

Dual Activities of Flower-Like Gold-Iron Oxide Nanozyme for Peroxidase-Mimicking and Glucose Detection

Nanozymes, constituting of inorganic nanomaterials, are the sustainable and cost-effective alternatives of the naturally abundant enzymes. For more than a decade, nanozymes have shown astonishingly enhanced enzymatic activity as compared to its naturally occurring counterpart and emerged as a potential platform in biomedical science. The current study reports a novel flower shaped gold-iron oxide nanocomposite prepared via a facile and green solution phase redox mediated synthesis. The precursor gold salt conversion to nanometallic Au(0) is mediated by iron metal powder, which acts both as reductant and metal source in the resultant gold nanoparticle decorated iron oxide nanocomposite. Calcination of the synthesized nanocomposites leads to morphological evolution into unique flower shape with improved homogeneity between gold and iron components along with metal surface exposure. The gold-iron oxide nanocomposites have been utilized first time for peroxidase mimicking study and exhibit enhanced catalytic activity at 25 °C with low Michaelis-Menten constant (Km) and higher maximum reaction velocity (Vmax) as compared to the natural enzyme Horseradish peroxidase (HRP). In addition, combined assembly of this nanozyme with natural enzyme glucose oxidase also serves a potential platform for the visible colorimetric detection and quantification of glucose with limit of detection (LOD) of 15 μM.

Lateral flow immunoassay using plasmonic scattering

The lateral flow immunoassay (LFIA) is one of the most successful sensing platforms for real-world point-of-care (POC) testing. However, achieving PCR-level sensitivity without compromising the inherent advantages of LFIA, such as rapid and robust operation, affordability, and naked-eye detection, has remained a primary challenge. In this study, a plasmonic scattering-utilising LFIA was proposed, created by transparentising a nitrocellulose membrane and placing a light-absorbing backing card under the membrane. This LFIA minimised the background signal from its matrix, leading to substantially enhanced sensitivity and enabling naked-eye detection of the plasmonic scattering signal from gold nanoparticles without optics. Our plasmonic scattering-utilising LFIA showed an approximately 2600-4400 times higher detection limit compared with that of commercial LFIAs in influenza A assays. In addition, it exhibited 90% sensitivity in clinical validation, approaching PCR-level sensitivity, while commercial LFIAs showed 23-30% sensitivity. The plasmonic scattering-utilising LFIA plays a ground-breaking role in POC diagnostics and significantly boosts follow-up research.

Nanofabrication for Nanophotonics

Nanofabrication, a pivotal technology at the intersection of nanoscale engineering and high-resolution patterning, has substantially advanced over recent decades. This technology enables the creation of nanopatterns on substrates crucial for developing nanophotonic devices and other applications in diverse fields including electronics and biosciences. Here, this mega-review comprehensively explores various facets of nanofabrication focusing on its application in nanophotonics. It delves into high-resolution techniques like focused ion beam and electron beam lithography, methods for 3D complex structure fabrication, scalable manufacturing approaches, and material compatibility considerations. Special attention is given to emerging trends such as the utilization of two-photon lithography for 3D structures and advanced materials like phase change substances and 2D materials with excitonic properties. By highlighting these advancements, the review aims to provide insights into the ongoing evolution of nanofabrication, encouraging further research and application in creating functional nanostructures. This work encapsulates critical developments and future perspectives, offering a detailed narrative on the state-of-the-art in nanofabrication tailored for both new researchers and seasoned experts in the field.

Plasmon-Driven Chemistry

Plasmonic nanomaterials are promising photocatalysts due to their large optical cross sections and facile generation of nanoscale hotspot regions. They have been used to drive a range of photochemical reactions, including H2 dissociation, CO2 reduction, and ammonia synthesis, offering an exciting approach to light-driven chemistry. Deepening our understanding of how energy can be controllably transferred from the plasmonic nanomaterial to proximal reactants should lead to improvements in the efficiency and selectivity in plasmonic photocatalysis. Here we provide a comprehensive overview of plasmonic properties and explore different energy partitioning pathways. We focus on the importance of mapping molecular potential energy landscapes to understand reactivity and describe recent advancements in spectroscopic techniques, such as ultrafast surface-enhanced Raman spectroscopy, electron microscopy, and electrochemistry, that can aid in understanding how plasmonic nanomaterials can be used to shape potential energy surfaces and modify chemical outcomes. Additionally, we explore innovative hybrid plasmonic nanostructures such as antenna-reactor complexes, plasmonic single-atom catalysts, plasmonic picocavities, and chiral plasmonic substrates, all of which show great promise in advancing the field of plasmon-driven chemistry.

Exploring the impact of particle stability, size, and morphology on nanofluid thermal conductivity: A comprehensive review for energy applications

Recent advancements enhance the efficiency of energy conversion processes and leverage nanofluids-novel thermal fluids with nanoparticles (under 100 nm) suspended in conventional fluids. These nanofluids significantly alter thermophysical properties, notably thermal conductivity, which is crucial for evaluating their thermal performance. Despite three decades of intensive research, disagreements persist due to a lack of comprehensive data on how particle size, shape, stability, and others influence thermal conductivity. This review tries to fill this literature gap by critically reviewing how the characteristics that distinguish nanofluids from their micrometer-sized counterparts affect the stability and convective heat transfer. The study compares experimental results in a systemic way that addresses the reported inconsistencies and provides a general summary of the thermal behavior of nanofluids in energy systems. It has also pointed out the lack of reliable hybrid models considering all parameters affecting thermal conductivity. The current study assembles data from different analyses showing that a particle size within the 10-50 nm range may enhance thermal conductivity, depending on the base-fluid used. Likewise, the morphological options available, namely, spherical, ellipsoid, platelet, and blade-like, all have given promise for enhancing thermal conductivity, hence considering morphological issues. Finally, stability, defined by the zeta potential analyses, forms a vital criterion for the long-term sustainability of these enhancements. By consolidating experimental results across different research groups, this review highlights the variability and sometimes contradictory findings in thermal conductivity enhancements, ranging from negligible increases to over 50% improvement in specific nanofluids systems. The absence of reliable hybrid models encapsulating all influencing parameters for predicting thermal conductivity is critically addressed. It is concluded by identifying the main challenges in the field and offering recommendations for standardizing measurement techniques, which include the need for a unified model capable of predicting thermal conductivity enhancements with an accuracy of ±5%.

Differential evolution-optimized gold nanorods for enhanced photothermal conversion

Noble metallic nanoparticles (NPs) have shown great potential in the field of sustainable energy. Gold nanorods (AuNRs), known for their size-dependent optical and electrical characteristics, are strong candidates for various applications, particularly in solar energy conversion. Additionally, AuNRs are well-established nanomaterials in precision medicine. In this paper, we optimize the shape and size of AuNRs to maximize light-to-heat conversion based on a validated theoretical model. Utilizing the Differential Evolution (DE) algorithm, a robust metaheuristic optimization approach, we calculated the optimal size and shape of AuNRs for selected wavelengths. The aspect ratio (AR), defined as the ratio of the diameter to the length of the AuNRs, was a key parameter in the optimization process. The optimization results reveal that for shorter wavelengths, near-spherical AuNRs (AR of 0.71 and 0.75) demonstrate the highest efficiency, while for longer wavelengths, more elongated AuNRs (AR of 0.24 and 0.17) outperform others. This study also includes Computational Fluid Dynamics (CFD) calculations to evaluate the impact of optimized AuNRs on heat generation in a real-world scenario. A case study is presented in which lasers of different wavelengths irradiate a borosilicate glass embedded with a slab of AuNRs at its center. The results, reported as temperature distributions and temperature evolution during irradiation, indicate that the optimized AuNRs significantly enhance heat generation across various laser wavelengths. Specifically, temperature increases were observed as follows: from 2.28 to [Formula: see text] at 465 nm, from 1.91 to [Formula: see text] at 532 nm, from 1.7 to [Formula: see text] at 640 nm, from 40 to [Formula: see text] at 808 nm, and from 0.94 to [Formula: see text] at 980 nm, respectively. These findings underscore the effectiveness of the optimization process in enhancing photothermal conversion.

Chemical Interface Damping Revealed by Single-Particle Absorption Spectroscopy

Plasmon-induced interfacial charge separation is a promising way to efficiently extract energetic carriers through direct plasmon decay. This mechanism of charge transfer has been investigated by single-particle scattering spectroscopy, which measures the homogeneous plasmon line width. The line width is broadened by charge transfer, generally known as chemical interface damping. However, conflicting reports exist regarding the effect of chemical interface damping on the corresponding single-particle absorption spectrum, which is needed to accurately determine absolute light conversion efficiencies. This work aims to resolve this question by directly correlating absorption and scattering spectra of individual gold nanorods in the presence and absence of a charge-accepting interface. We find that for TiO2 coated nanorods, the absorption line width is indeed broadened due to chemical interface damping but is overall narrower than the scattering line width. Chemical interface damping is furthermore found to increase with larger resonance energies. The observed differences in line widths between absorption and scattering are elucidated within the context of an analytically tractable model describing the lowest energy optically bright and higher-order optically dark plasmon modes of the nanorod, including bulk, radiative, and chemical interface damping effects. Taken together, these results establish that single-particle absorption spectroscopy is capable of revealing interfacial charge injection by direct plasmon decay.

A Self-Driving Lab for Nano- and Advanced Materials Synthesis

The recent emergence of self-driving laboratories (SDL) and material acceleration platforms (MAPs) demonstrates the ability of these systems to change the way chemistry and material syntheses will be performed in the future. Especially in conjunction with nano- and advanced materials which are generally recognized for their great potential in solving current material science challenges, such systems can make disrupting contributions. Here, we describe in detail MINERVA, an SDL specifically built and designed for the synthesis, purification, and in line characterization of nano- and advanced materials. By fully automating these three process steps for seven different materials from five representative, completely different classes of nano- and advanced materials (metal, metal oxide, silica, metal organic framework, and core-shell particles) that follow different reaction mechanisms, we demonstrate the great versatility and flexibility of the platform. We further study the reproducibility and particle size distributions of these seven representative materials in depth and show the excellent performance of the platform when synthesizing these material classes. Lastly, we discuss the design considerations as well as the hardware and software components that went into building the platform and make all of the components publicly available.

Polydopamine-mediated gold nanoparticle coating strategy and its application in photothermal polymerase chain reaction

Materials with high light-to-heat conversion efficiencies offer valuable strategies for remote heating. These materials find wide applications in photothermal therapy, water distillation, and gene delivery. In this study, we investigated a universal coating method to impart photothermal features to various surfaces. Polydopamine, a well-known adhesive material inspired by mussels, served as an intermediate layer to anchor polyethyleneimine and capture gold nanoparticles. Subsequently, the coated surface underwent electroless gold deposition to improve photothermal heating efficiency by increasing light absorption. This process was analyzed through scanning electron microscopic imaging and absorbance measurements. To demonstrate functionality, the coated surface was photothermally heated using a light-emitting diode controlled with a microprocessor, targeting the metal regulatory transcription factor 1 gene-a marker for osteoarthritis-and the S gene of the severe fever with thrombocytopenia syndrome virus. Successful amplification of the target genes was confirmed after 34 polymerase chain reaction cycles in just 12 min, verified by gel electrophoresis, demonstrating its diagnostic applicability. Overall, this simple photothermal coating method provides versatile utility, and is applicable to diverse surfaces such as membranes, tissue culture dishes, and microfluidic systems.

One-Step Synthesis of Poly(2-alkyl-2-oxazoline)-Coated Gold Nanospheres: A Greener Approach for Biomedical Uses

The biological application of gold nanospheres (AuNSs) is often constrained by their stability and cytotoxicity. We present a greener synthetic approach that gives a simple and more environmentally friendly route to synthesizing AuNSs for biomedical applications. In this study, we detail a novel one-step, green synthesis of poly(2-alkyl-2-oxazoline) (POx)-coated AuNSs, which eliminates the need for additional reducing and stabilizing agents. The impact of the polymer structure on the nanoparticle formulation kinetics and nanoparticle characteristics is thoroughly investigated, revealing that the terminal functional group and the alkyl side chain significantly influence the reduction and stabilization process of AuNSs. Finally, POx-coated AuNSs were tested in vitro against F98 glioblastoma cells and proved to be usable without significant toxicity up to 75 μM. Herein, the outlined rapid and efficient method of the preparation of POx-coated AuNSs serves as a foundation for advancing the development of complex AuNSs tailored for biomedical applications.

Controlled electrochemical fabrication of large and stable gold nanorods with reduced cytotoxicity

Gold nanorods (GNRs) are valued for their tunable surface plasmon resonance (SPR) and unique optical properties, but precise control over their size and shape remains challenging. Current synthesis techniques often yield polydisperse samples and require high concentrations of cytotoxic surfactants, limiting their biomedical applications. In this study, we introduce a novel electrochemical synthesis method that offers precise control of GNR characteristics by leveraging open circuit potential (OCP) data from colloidal synthesis. This approach involves the electrochemical growth of gold nano-seeds immobilized on fluorine-doped tin oxide (FTO) substrates, using physical vapor deposition (PVD) followed by thermal annealing to generate the Au seeds. This eliminates the need for seed solutions and significantly reduces surfactant usage. By optimizing electrochemical parameters, we produce uniform GNRs up to 700 nm in length, surpassing the typical 100 nm size from traditional methods. These larger GNRs exhibit superior optical and thermal properties, making them ideal for biomedical imaging, photothermal therapy, and applications requiring deeper tissue penetration. Their increased size also enhances stability, biosensing sensitivity, and circulation time, making them suitable for drug delivery and catalysis. This scalable method improves nanorod growth understanding while addressing cytotoxicity concerns.

Enhanced Cognitive and Memory Functions via Gold Nanoparticle-Mediated Delivery of Afzelin through Synaptic Modulation Pathways in Alzheimer's Disease Mouse Models

Gold nanoparticles (AuNPs) are valuable tools in pharmacological and biological research, offering unique properties for drug delivery in the treatment of neurodegenerative diseases. This study investigates the potential of gold nanoparticles loaded with afzelin, a natural chemical extracted from Ribes fasciculatum, to enhance its therapeutic effects and overcome the limitations of using natural compounds regarding low productivity. We hypothesized that the combined treatment of AuNPs with afzelin (AuNP-afzelin) would remarkably enforce neuroprotective effects compared with the single treatment of afzelin. Central administration of AuNP-afzelin (10 ng of afzelin) indicated improvements in cognition and memory-involved assessments of behavioral tests, comparing single treatments of afzelin (10 or 100 ng of afzelin) in scopolamine-induced AD mice. AuNP-afzelin also performed superior neuroprotective effects of rescuing mature neuronal cells and recovered cholinergic dysfunction compared to afzelin alone, according to further investigations of BDNF-pCREB-pAkt signaling, long-term potentiation, and doublecortin (DCX) expression in the hippocampus. This study highlights the potential of afzelin with gold nanoparticles as a promising therapeutic approach for mitigating cognitive impairments associated with neurodegenerative diseases and offers a new avenue for future research and drug development.

Gold Nanoparticles as a Tool to Detect Biomarkers in Osteoarthritis: New Insights

Extensive research over the years has revealed the remarkable potential of gold nanoparticles (AuNPs) for detecting biomarkers in osteoarthritis (OA). AuNPs are a promising class of nanomaterials offering a wide range of diagnostic and clinical applications. It provides an effective and robust framework for qualitative and quantitative analysis of biomarkers present in the biological fluids of OA patients. AuNPs as theranostics have gained significant attention due to their discrete physical and optical characteristics, including localized surface plasmon resonance (LSPR), fluorescence, surface-enhanced Raman scattering, and quantized charging effect. These unique properties provide AuNPs as an excellent scaffold for ligand multiplexing, allowing accrued sensitivity for biomarker detection. Several reports have delved into the LSPR properties of the kinetics of biological interactions between the ligand and analyte. Tuneable radiative properties of AuNPs coupled with surface engineering allow facile detection of biomarkers in biological fluids. Herein, we have presented a comprehensive summary of distinct biomarkers generated from different molecular pathological processes in OA. An armamentarium of diagnostic methodologies such as aptamer conjugation, antibody coupling, ligand anchoring, and peptide decoration on the surface of AuNPs facilitates the identification and quantification of biomarkers. Additionally, a diverse range of sensing strategies for biomarker spotting, along with current challenges and future perspectives, have also been well delineated in the present manuscript.

Graphical Abstract

Plasmonic Hot-Carrier Engineering at Bimetallic Nanoparticle/Semiconductor Interfaces: A Computational Perspective

Plasmonic catalysis employs plasmonic metals such as Ag, Au, Cu, and Al, typically in combination with semiconductors, to drive diverse redox chemical reactions. These metals are good at harnessing sunlight, owing to their strong absorption cross-sections and tunable absorption peaks within the visible range of the solar spectrum. Unfortunately, facilitating plasmon-induced hot-carrier separation and subsequently harvesting them to improve catalytic efficiencies has been a problem at monometallic particle-semiconductor interfaces. To overcome this issue, this perspective focuses on recent computational methods and studies to discuss the advantages of designing bimetallic particles (core-shell or core-satellite), with a plasmonic-metal core and a less-plasmonic-metal shell on top, and coupling them with semiconductors. The aim of this approach is to favorably modify the interface between the plasmonic-metal particle and the semiconductor by introducing a thin section of a non-plasmonic metal in between. This approach is expected to enhance hot-carrier separation at the interface, preventing fast electron-hole recombination within the plasmonic-metal particle. Through a careful design of such bimetal/semiconductor configurations, by varying the size and composition of the non-plasmonic metal for example, and through appropriate utilization of quantum-mechanical modeling and experimental techniques, it is anticipated that plasmonic hot-carrier generation and separation processes can be studied and controlled in such systems, thereby enabling more-efficient plasmonic devices.

Sensitive Colorimetric Lateral Flow Assays Enabled by Platinum-Group Metal Nanoparticles with Peroxidase-Like Activities

The last several decades have witnessed the success and popularity of colorimetric lateral flow assay (CLFA) in point-of-care testing. Driven by increasing demand, great efforts have been directed toward enhancing the detection sensitivity of CLFA. Recently, platinum-group metal nanoparticles (PGM NPs) with peroxidase-like activities have emerged as a type of promising colorimetric labels for enhancing the sensitivity of CLFA. By incorporating a simple and rapid post-treatment process, the PGM NP-based CLFAs are orders of magnitude more sensitive than conventional gold nanoparticle-based CLFAs. In this perspective, the study begins with introducing the design, synthesis, and characterization of PGM NPs with peroxidase-like activities. The current techniques for surface modification of PGM NPs are then discussed, followed by operation and optimization of PGM NP-based CLFAs. Afterward, opinions are provided on the social impact of PGM NP-based CLFAs. Lastly, this perspective is concluded with an outlook of future research directions in this emerging field, where the challenges and opportunities are discussed.

Dual Protein Corona-Mediated Target Recognition System for Visual Detection and Single-Molecule Counting of Nucleic Acids

Rapid, highly sensitive, and specific nucleic acid detection plays a crucial role in advancing point-of-care (POC) diagnostics for pathogens and viruses, cancer monitoring, and optimizing clinical treatments. Herein, leveraging the precise recognition ability of CRISPR/dCas9 and the powerful localized surface plasmon resonance (LSPR) of gold nanoparticles (AuNPs), we report the design of a dual protein corona-mediated detection platform to simultaneously fulfill rapid POC testing and single-molecule counting of nucleic acids in a one-pot and one-step manner. This system uses guide RNA as a molecular bridge to anchor dCas9 protein onto AuNPs, forming artificial protein coronas. Upon recognizing a target, the interaction between the two protein coronas on the same nucleic acid molecule triggers cross-linked aggregation of AuNPs. Then, a target as low as 100 aM can be visually detected within 30 min, making the platform particularly well-suited for rapid POC application and the screening of emerging epidemics. Additionally, the superior LSPR properties of AuNPs increase the light-scattering signal generated during target-induced aggregation, enabling the visualization of the aggregated AuNPs as diffraction-limited spots under confocal microscopy. By counting these spots, the platform achieves unprecedented detection sensitivity, identifying a target as low as 1 aM, which is equivalent to just 6 molecules in a 10 μL system, demonstrating single-molecule detection capability. This dual protein corona-mediated detection system offers exceptional promise for large-scale screening of pathogenic viruses and the early detection of cancer, particularly in applications requiring ultrahigh sensitivity at the single-molecule level.

Fabrication of nanoparticles with precisely controllable plasmonic properties as tools for biomedical applications

Metal nanoparticles are established tools for biomedical applications due to their unique optical properties, primarily attributed to localized surface plasmon resonances. They show distinct optical characteristics, such as high extinction cross-sections and resonances at specific wavelengths, which are tunable across the wavelength spectrum by modifying the nanoparticle geometry. These attributes make metal nanoparticles highly valuable for sensing and imaging in biology and medicine. However, their widespread adoption is hindered due to challenges in consistent and accurate nanoparticle fabrication and functionality as well as due to nanotoxicological concerns, including cell damage, DNA damage, and unregulated cell signaling. In this study, we present a fabrication approach using nanoimprint lithography in combination with thin film deposition which yields highly homogenous nanoparticles in size, shape and optical properties with standard deviations of the main geometry parameters of less than 5% batch-to-batch variation. The measured optical properties closely match performed simulations, indicating that pre-experimental modelling can effectively guide the design of nanoparticles with tailored optical properties. Our approach also enables nanoparticle transfer to solution. Particularly, we show that the surface coating with a PEG polymer shell ensures stable dispersions in buffer solutions and complex cell media for at least 7 days. Furthermore, our in vitro experiments demonstrate that these nanoparticles are internalized by cells via endocytosis, exhibit good biocompatibility, and show minor cytotoxicity, as evidenced by high cell viability. In the future, our high-precision nanoparticle fabrication method together with tunable surface plasmon resonance and reduced nanotoxicity will offer the possibility to replace conventional nanomaterials for biomedical applications that make use of an optical response at precise wavelengths. This includes the use of the nanoparticles as contrast agents for imaging, as probes for targeted photothermal cancer therapy, as carriers for controlled drug delivery, or as probes for sensing applications based on optical detection principles.

Exploring the application of metal-based photothermal agents in photothermal therapy combined with immune checkpoint therapy

Photothermal therapy (PTT), a popular local treatment that uses heat to ablate tumors, has limited efficacy in addressing metastatic and deeply located tumors when used alone. Integrating PTT with immunotherapy not only yields a synergistic effect but also promotes cancer regression and confers the benefit of immune memory, which can surmount the challenges faced by PTT when used in isolation. Metal-based nanomaterials, renowned for their superior photothermal conversion efficiency and distinctive photochemical properties, have been extensively researched and applied in the field of PTT. This review summarizes the latest developments in combination therapies, with a specific focus on the combination of PTT and immune checkpoint therapy (ICT) for cancer treatment, including a comprehensive overview of the recent advancements in noble metal-based and 2D transition metal chalcogenides (TMDCs)-based photothermal agents, and their anticancer effect when combining PTT with immune checkpoint blockades (anti-CTLA-4 and anti-PD-L1) therapy. The goal of this review is to present an overview of the application, current challenges and future prospects of metal-based photothermal agents in PTT combined with ICT for cancer treatment.

99mTc-labeled benzenesulfonamide derivative-entrapped gold citrate nanoparticles as an auspicious tumour targeting

Sulfonamide derivatives are a significant class of medicinal compounds. Gold nanoparticles (AuNPs) offer precise cancer treatment through targeted delivery, boasting high drug-loading capacity and low toxicity. This study aimed to develop and evaluate 99mTc-labeled benzenesulfonamide derivative-entrapped gold citrate nanoparticles as a tumor-targeting agent. A novel benzenesulfonamide derivative bearing a pyridine moiety was synthesized. Compound 3 (4-((3-cyano-4-(2,4-dichlorophenyl)-6-phenylpyridin-2-yl)amino)-N-(diaminomethylene)benzenesulfonamide) exhibited remarkable anti-cancer activity against MCF-7 cells. The chemical reduction method was employed to create compound 3-citrate-AuNPs. A comprehensive examination of the synthesized nano-platform was conducted, including zeta potential, size analysis, radiochemical yield, and in-vivo biodistribution in tumor-bearing mice. The nano-platform was successfully produced with good stability, optimal particle size (9 nm diameter for AuNPs), and high radiochemical purity for [99mTc]Tc-compound 3 (88.31 ± 2.14%). In-vivo investigations revealed that intravenously administered [99mTc]Tc-compound 3-citrate-AuNPs accumulated in tumors with a high target-to-non-target ratio. The findings validate the efficacy of the novel [99mTc]Tc-compound 3-citrate-AuNPs platform as a tumor-targeting agent.

Machine Learning-Integrated Numerical Simulation for Predicting Photothermal Conversion Performance of Metallic Nanofluids

Photothermal conversion in metallic nanofluids, driven by localized surface plasmon resonances, is essential for applications in biomedicine, such as cancer treatment and biosensing. However, accurately predicting photothermal conversion performance, particularly the spatial temperature distribution, remains challenging due to the complex interplay of nanoparticle properties. Existing experimental methods are labor-intensive and often insufficient in providing detailed thermal profiles. Here, a novel approach that integrates machine learning is presented with numerical simulations to predict the photothermal conversion efficiency and spatial temperature distribution in gold nanorod nanofluid. The method employs Discrete Dipole Approximation for optical property calculations, Monte Carlo simulations for light transport, and finite element methods for temperature distribution modeling. The machine learning model, trained on 1,024 cases of photothermal conversion efficiency and 2,016 cases of temperature fields, achieves rapid and accurate predictions with a high correlation coefficient (R2 = 0.972) to simulation results. This approach not only streamlines the prediction process but also provides an accessible tool for optimizing nanoparticle design, with significant implications for advancing biomedicine, energy, and sensor technologies.

Photonic Nanomaterials for Wearable Health Solutions

This review underscores the transformative potential of photonic nanomaterials in wearable health technologies, driven by increasing demands for personalized health monitoring. Their unique optical and physical properties enable rapid, precise, and sensitive real-time monitoring, outperforming conventional electrical-based sensors. Integrated into ultra-thin, flexible, and stretchable formats, these materials enhance compatibility with the human body, enabling prolonged wear, improved efficiency, and reduced power consumption. A comprehensive exploration is provided of the integration of photonic nanomaterials into wearable devices, addressing material selection, light-matter interaction principles, and device assembly strategies. The review highlights critical elements such as device form factors, sensing modalities, and power and data communication, with representative examples in skin patches and contact lenses. These devices enable precise monitoring and management of biomarkers of diseases or biological responses. Furthermore, advancements in materials and integration approaches have paved the way for continuum of care systems combining multifunctional sensors with therapeutic drug delivery mechanisms. To overcome existing barriers, this review outlines strategies of material design, device engineering, system integration, and machine learning to inspire innovation and accelerate the adoption of photonic nanomaterials for next-generation of wearable health, showcasing their versatility and transformative potential for digital health applications.

The Impact of Pistacia khinjuk plant gender on silver nanoparticle synthesis: Are extracts of root obtained from female plants preferentially used?

Pistacia khinjuk, a dioecious plant native to Southeast Anatolia, Turkey, features distinct male and female individuals with varying bioactive compound profiles. This study investigates the gender-specific phytochemical composition of root extracts from male and female Pistacia khinjuk plants and their influence on the green synthesis of silver nanoparticles. Using natural bioactive compounds such as polyphenols, flavonoids, alkaloids, and terpenoids as reducing and stabilizing agents, the study demonstrates significant differences between the nanoparticles synthesized from male and female root extracts. Female root extracts, with their higher polyphenolic content, produced silver nanoparticles that were smaller in size (150.1 nm) and more stable, as indicated by a zeta potential of -32.5 mV. In comparison, the silver nanoparticles synthesized from male root extracts were larger in size (213.8 nm) and exhibited a less negative zeta potential of -21.36 mV. Additionally, silver nanoparticles derived from female root extracts showed superior antioxidant activity and greater antibacterial efficacy against Staphylococcus aureus and Escherichia coli, as reflected in larger inhibition zones. These findings highlight the potential of Pistacia khinjuk root extracts for sustainable nanoparticle synthesis and underscore the value of gender-specific bioactive compounds in advancing green technologies and biomedical applications.

Lignosulfonate as a versatile regulator for the mediated synthesis of Ag@AgCl nanocubes

The remarkable catalytic activity, optical properties, and electrochemical behavior of nanomaterials based on noble metals (NM) are profoundly influenced by their physical characteristics, including particle size, morphology, and crystal structure. Effective regulation of these parameters necessitates a refined methodology. Lignin, a natural aromatic compound abundant in hydroxyl, carbonyl, carboxyl, and sulfonic acid groups, has emerged as an eco-friendly surfactant, reducing agent, and dispersant, offering the potential to precisely control the particle size and morphology of NM-based nanomaterials. In this study, lignosulfonate (LS) was utilized as a versatile regulator efficient in the capacities of reduction, capping, and dispersal for the synthesis of Ag@AgCl nanocubes. LS concentration and reaction time were identified as crucial factors impacting the ultimate particle size and morphology of Ag@AgCl nanocubes. The Ag@AgCl nanocubes, with a particle size of 30 ± 10 nm, were successfully synthesized under the optimized conditions of a 1.0 mM LS concentration and a 1-hour reaction period. As a reducing agent, LS facilitates the conversion of silver ions originating from AgCl to silver nanoparticles, following an etching-like mechanism that yields AgCl seeds with a uniform cubic particle size. The obtained Ag@AgCl nanocubes exhibit a stable morphology and excellent dispersion characteristics.

Plasmonic Nanoparticles for Photothermal Therapy: Benchmarking of Photothermal Properties and Modeling of Heating at Depth in Human Tissues

Many different types of nanoparticles have been developed for photothermal therapy (PTT), but directly comparing their efficacy as heaters and determining how they will perform when localized at depth in tissue remains complex. To choose the optimal nanoparticle for a desired hyperthermic therapy, it is vital to understand how efficiently different nanoparticles extinguish laser light and convert that energy to heat. In this paper, we apply photothermal mass conversion efficiency (η m ) as a metric to compare nanoparticles of different shapes, sizes, and conversion efficiencies. We selected silica-gold nanoshells (AuNShells), gold nanorods (AuNRs), and gold nanostars (AuNStars) as three archetypal nanoparticles for PTT and measured the η m of each to demonstrate the importance of considering both photothermal efficiency and extinction cross section when comparing nanoparticles. By utilizing a Monte Carlo model, we further applied η m to model how AuNRs performed when located at tissue depths of 0-30 mm by simulating the depth penetration of near-infrared (NIR) laser light. These results show how nanoparticle concentration, laser power, and tissue depth influence the ramp time to a hyperthermic temperature of 43 °C. The methodology outlined in this paper creates a framework to benchmark the heating efficacy of different nanoparticle types and a means of estimating the feasibility of nanoparticle-mediated PTT at depth in the NIR window. These are key considerations when predicting the potential clinical impact in the early stages of nanoparticle design.

Development of a portable SERS tool to evaluate the effectiveness of washing methods to remove pesticide residue from fruit surface

BACKGROUND

Pesticides are widely used in agriculture to control pests and enhance crop yields. However, post-harvest, there are growing concerns about the potential health risks posed by pesticide residues on produce surfaces. Analyzing these residues is challenging due to their typically low concentrations and the potential interference from the complex matrix of the produce's surface. The problem addressed in this study is the need for a sensitive, rapid, and on-site capable method to detect and quantify pesticide residues on agricultural products.

RESULTS

We developed a portable surface-enhanced Raman spectrometer (SERS)-based approach that offers a rapid 10-min turnaround, simplified protocol, on-site capability, and high sensitivity. Using the new analytical method, we evaluated pesticide residues on fruit surfaces after household or industrial postharvest washing, specifically the efficacy in removing the fungicide ferbam from peach surfaces. The limit of detection (LOD) for our method was determined to be 0.012 mg/kg, significantly lower than the U.S. Environmental Protection Agency's regulated limit of 7 mg/kg for ferbam on peaches. Our data shows that soaking in tap water for 1 min is the least effective method for removing ferbam, with insignificant difference from the control group. In contrast, soaking in a vinegar-water or NaHCO3-water solution for 5 min, as well as in a sodium hypochlorite solution (12 % available chlorine) for 1 or 5 min, proved to be the most effective methods. Extended soaking improved pesticide removal for tap water, vinegar, and NaHCO3, while in the chlorine groups, the effect was insignificant. SERS analysis revealed negligible penetration of ferbam into peach flesh and the inner surface of the skin.

SIGNIFICANCE

This study introduces an innovative method for measuring pesticide residues, significantly enhancing our understanding of pesticide removal and penetration. This new analytical approach is crucial for effectively detecting pesticides and mitigating their exposure through food sources.

Label-Free Surface-Enhanced Raman Scattering for Genomic DNA Cytosine Methylation Reading

DNA methylation has been widely studied with the goal of correlating the genome profiles of various diseases with epigenetic mechanisms. Multiple approaches have been developed that employ extensive steps, such as bisulfite treatments, polymerase chain reactions (PCR), restriction digestion, sequencing, mass analysis, etc., to identify DNA methylation. In this article, we report a facile label-free surface-enhanced Raman scattering (SERS) spectroscopy system that utilizes gold nanoparticles (AuNPs) for signal enhancement of methylated DNA. The key innovation of this work is to use anionic nanoparticles at a high ionic strength to introduce the aggregation of AuNPs with anionic DNA. When target methylated DNA is present, the presence of a methyl group in the cytosine C5 position of CpG sites induces a Raman peak at 1350 cm-1. Our amplification-free system has a limit of detection (LOD) of 5% and a limit of quantification (LOQ) of 16% with good specificity. The method was applied to determine the hypermethylated levels of the germline of colorectal cancer cell lines SW48 and SW480. Our simple label-free method holds the potential to read the disease-associated methylation of genomic DNA.

MoS2-Plasmonic Hybrid Platforms: Next-Generation Tools for Biological Applications

The combination of molybdenum disulfide (MoS2) with plasmonic nanomaterials has opened up new possibilities in biological applications by combining MoS2's biocompatibility and high surface area with the optical sensitivity of plasmonic metals. These MoS2-plasmonic hybrid systems hold great promise in areas such as biosensing, bioimaging, and phototherapy, where their complementary properties facilitate improved detection, real-time visualization, and targeted therapeutic interventions. MoS2's adjustable optical features, combined with the plasmon resonance of noble metals such as gold and silver, enhance signal amplification, enabling detailed imaging and selective photothermal or photodynamic therapies while minimizing effects on healthy tissue. This review explores various synthesis strategies for MoS2-plasmonic hybrids, including seed-mediated growth, in situ deposition, and heterojunction formation, which enable tailored configurations optimized for specific biological applications. The primary focus areas include highly sensitive biosensors for detecting cancer and infectious disease biomarkers, high-resolution imaging of cellular dynamics, and the development of phototherapy methods that allow for accurate tumor ablation through light-induced thermal and reactive oxygen species generation. Despite the promising advancements of MoS2-plasmonic hybrids, translating these platforms into clinical practice requires overcoming considerable challenges, such as synthesis reproducibility, toxicity, stability in physiological conditions, targeted delivery, and scalable manufacturing. Addressing these challenges is essential for realizing their potential as next-generation tools in diagnostics and targeted therapies.

Overcoming optical losses in thin metal-based recombination layers for efficient n-i-p perovskite-organic tandem solar cells

Perovskite-organic tandem solar cells (P-O-TSCs) hold substantial potential to surpass the theoretical efficiency limits of single-junction solar cells. However, their performance is hampered by non-ideal interconnection layers (ICLs). Especially in n-i-p configurations, the incorporation of metal nanoparticles negatively introduces serious parasitic absorption, which alleviates photon utilization in organic rear cell and decisively constrains the maximum photocurrent matching with front cell. Here, we demonstrate an efficient strategy to mitigate optical losses in Au-embedded ICLs by tailoring the shape and size distribution of Au nanoparticles via manipulating the underlying surface property. Achieving fewer, smaller, and more uniformly spherical Au nanoparticles significantly minimizes localized surface plasmon resonance absorption, while maintaining efficient electron-hole recombination within ICLs. Consequently, optimized P-O-TSCs combining CsPbI2Br with various organic cells benefit from a substantial current gain of >1.5 mA/cm2 in organic rear cells, achieving a champion efficiency of 25.34%. Meanwhile, optimized ICLs contribute to improved long-term device stability.

Functionalized Nanomaterials In Pancreatic Cancer Theranostics And Molecular Imaging

Pancreatic cancer (PC) is one of the most fatal malignancies in the world. This lethality persists due to lack of effective and efficient treatment strategies. Pancreatic ductal adenocarcinoma (PDAC) is an aggressive epithelial malignancy which has a high incidence rate and contributes to overall cancer fatalities. As of 2022, pancreatic cancer contributes to about 3 % of all cancers globally. Over the years, research has characterised germline predisposition, the origin cell, precursor lesions, genetic alterations, structural alterations, transcriptional changes, tumour heterogeneity, metastatic progression, and the tumour microenvironment, which has improved the understanding of PDAC carcinogenesis. By using molecular-based target therapies, these fundamental advancements support primary prevention, screening, early detection, and treatment. The focus of this review is the use of targeted nanoparticles as an alternative to conventional pancreatic cancer treatment due to the various side effects of the latter. The principles of nanoparticle based cancer therapy is efficient targeting of tumour cells via enhanced permeability and retention (EPR) effects and decrease the chemotherapy side effects due to their non-specificity. To increase the efficiency of existing therapies and modify target nanoparticles, several molecular markers of pancreatic cancer cells have been identified. Thus pancreatic cancer cells can be detected using appropriately functionalized nanoparticles with specific signalling molecules. Once cancer has been identified, these nanoparticles can kill the tumour by inducing hyperthermia, medication delivery, immunotherapy or gene therapy. As potent co-delivery methods for adjuvants and tumor-associated antigens; nanoparticles (NPs) have demonstrated significant promise as delivery vehicles in cancer therapy. This ensures the precise internalization of the functionalized nanoparticle and thus also activates the immune system effectively against tumor cells. This review also discusses the immunological factors behind the uptake of functionalized nanoparticles in cancer therapies. Theranostics, which combine imaging and therapeutic chemicals in a single nanocarrier, are the next generation of medicines. Pancreatic cancer treatment may be revolutionised by the development of a tailored nanocarrier with diagnostic, therapeutic, and imaging capabilities. It is extremely difficult to incorporate various therapeutic modalities into a single nanocarrier without compromising the individual functionalities. Surface modification of nanocarriers with antibodies or proteins will enable to attain multifunctionality which increases the efficiency of pancreatic cancer therapy.

Biomedical applications of peptide-gold nanoarchitectonics

Gold nanoparticles (AuNPs) have become a focus of interest in biomedicine due to their unique properties. By attaching peptides to these nanoparticles (NPs), they can be utilized for a wide range of applications. Peptides, which are short chains of amino acids, can be customized for specific molecular interactions, making them ideal for delivering AuNPs to particular cells or tissues. One of the peptide-AuNP-based bio-nano technological approaches involves targeted drug delivery. Including peptides as targeting agents, these NPs can be designed to bind to specific cell receptors or biomarkers. This allows for the direct delivery of therapeutic agents to diseased cells while minimizing unwanted side effects, improving the effectiveness of treatments. Additionally, peptide-functionalized AuNPs (PAuNPs) are crucial for imaging and diagnostics. By functionalizing the NPs with peptides that bind to specific molecular targets, such as cancer biomarkers, these NPs can be used to visualize diseased tissues. This enables the early detection of diseases and helps in determining the severity of conditions for better diagnosis and treatment outcomes. Moreover, PAuNPs have displayed promising potential in photothermal therapy. Once PAuNPs uptake and penetrate target cancer cells effectively, these NPs generate heat when exposed to specific wavelengths of light, efficiently eliminating tumors while preserving healthy surrounding tissues. Therefore, in this paper, we systematically review the potential of PAuNPs in various biomedical applications, including therapy and diagnosis, providing a future perspective.

Influence of Gold Nanoparticles on eNOS Localization in Gill Tissues: Advancements in Immunofluorescence Techniques

This study optimizes immunofluorescence techniques using gold nanoparticles (AuNPs) to improve visualization of endothelial nitric oxide synthase (eNOS) in gill tissue. Two types of AuNP dispersions, stabilized in phosphate buffered saline (PBS) and citrate buffer (CB), were evaluated for their imaging performance. AuNPs suspended in PBS provided significantly better optical contrast due to uniform distribution and effective tissue attachment, whereas citrate-suspended AuNPs exhibited aggregation, resulting in reduced contrast. These results highlight the influence of suspension media on AuNP performance, particularly in balancing fluorescence signals to improve contrast. The PBS suspension allowed clearer visualization of eNOS, highlighting the role of AuNP compatibility in improving immunofluorescence results. This study highlights the importance of strategic selection of AuNP dispersions in contrast agent design and provides insights for advanced imaging applications where sensitivity and accurate localization of biomolecules are essential. By refining the use of AuNPs as contrast enhancers, this approach offers potential improvements in bioimaging accuracy, facilitating more precise visualization in complex tissue environments.

Cancer treatment approaches within the frame of hyperthermia, drug delivery systems, and biosensors: concepts and future potentials

This work presents a review of the therapeutic modalities and approaches for cancer treatment. A brief overview of the traditional treatment routes is presented in the introduction together with their reported side effects. A combination of the traditional approaches was reported to demonstrate an effective therapy until a few decades ago. With the improvement in the fabrication of nanomaterials, targeted therapy represents a novel therapeutic approach. This improvement established on nanoparticles is categorized into hyperthermia, drug delivery systems, and biosensors. Hyperthermia presents a personalized medicine-based approach in which targeted zones are heated up until the diseased tissue is destroyed by the thermal effect. The use of magnetic nanoparticles further improved the effectiveness of hyperthermia owing to the enhanced heating action, further increasing the accuracy of the targeting process. Nanoparticle-based biosensors present a smart nanodevice that can detect, monitor, and target tumor tissues by following the biomarkers in the body fluids. Magnetic nanoparticles offer a controlled thermo-responsive device that can be manipulated by changing the magnetic field, offering a more personalized and controlled hyperthermia therapeutic modality. Similarly, gold nanoparticles offer an effective aid in the hyperthermia treatment approach. Furthermore, carbon nanotubes and metal-organic frameworks present a cutting-edge approach to cancer treatment. A combination of functionalized nanoparticles offers a unique route for drug delivery systems, in which therapeutic agents carried by nanoparticles are guided into the human body and then released in the target spot.

Exploring size-dependent optical property alterations in fine-tuning intermetallic PdCd nanocube sizes

Tuning the size of intermetallic nanocrystals is challenging due to the conflicting effects of surface free energy and surface diffusion on the disorder-to-order phase transition during wet-chemistry growth. Herein, we synthesized intermetallic PdCd nanocubes with tunable sizes ranging from 8 to 15 nm by adjusting the Cd precursor concentrations using a wet-chemistry approach. This process shares a mechanism of size tuning similar to quantum dot synthesis, involving the regulation of monomer concentration determined by the precursor concentrations. The intermetallic PdCd nanocubes exhibit distinct size-dependent optical properties compared to platinum group metal nanocrystals of similar size ranges, with increased light-induced catalytic enhancement as size increases. The 15 nm-sized nanocubes exhibited the most significant light-induced catalytic enhancement, reaching 3.3 times, while the 8 nm-sized nanocubes showed only a 1.6-fold enhancement in 4-nitrophenol reduction. This study emphasizes the importance of tuning the size of intermetallic nanocrystals, providing valuable insights for future exploration of their size-dependent properties.

Advancements in nanotechnology-driven photodynamic and photothermal therapies: mechanistic insights and synergistic approaches for cancer treatment

Cancer is a disease that involves uncontrolled cell division triggered by genetic damage to the genes that control cell growth and division. Cancer starts as a localized illness, but subsequently spreads to other areas in the human body (metastasis), making it incurable. Cancer is the second most prevalent cause of mortality worldwide. Every year, almost ten million individuals get diagnosed with cancer. Although different cancer treatment options exist, such as chemotherapy, radiation, surgery and immunotherapy, their clinical efficacy is limited due to their significant side effects. New cancer treatment options, such as phototherapy, which employs light for the treatment of cancer, have sparked a growing fascination in the cancer research community. Phototherapies are classified into two types: photodynamic treatment (PDT) and photothermal therapy (PTT). PDT necessitates the use of a photosensitizing chemical and exposure to light at a certain wavelength. Photodynamic treatment (PDT) is primarily based on the creation of singlet oxygen by the stimulation of a photosensitizer, which is then used to kill tumor cells. PDT can be used to treat a variety of malignancies. On the other hand, PTT employs a photothermal molecule that activates and destroys cancer cells at the longer wavelengths of light, making it less energetic and hence less hazardous to other cells and tissues. While PTT is a better alternative to standard cancer therapy, in some irradiation circumstances, it can cause cellular necrosis, which results in pro-inflammatory reactions that can be harmful to therapeutic effectiveness. Latest research has revealed that PTT may be adjusted to produce apoptosis instead of necrosis, which is attractive since apoptosis reduces the inflammatory response.

Investigation of a broad diversity of nanoparticles, including their processes, as well as toxicity testing in diverse organs and systems

Nanotechnology arising in wide-ranging areas, covers extensively different ranges of approaches attained from fields such as biology, chemistry, physics, and medicine engineering. Nanoparticles are a necessary part of nanotechnology effectually applied in the cure of a number of diseases. Nanoparticles have gained significant importance due to their unique properties, which differ from their bulk counterparts. These distinct properties of nanoparticles are primarily influenced by their morphology, size, and size distribution. At the nanoscale, nanoparticles exhibit behaviours that can enhance therapeutic efficacy and reduce drug toxicity. Their small size and large surface area make them promising candidates for applications such as targeted drug delivery, where they can improve treatment outcomes while minimizing adverse effects. The harmful effects of nanoparticles on the environment were critically investigated to obtain appropriate results and reduce the risk by incorporating the materials. Nanoparticles tend to penetrate the human body, clear the biological barriers to reach sensitive organs and are easily incorporated into human tissue, as well as dispersing to the hepatic tissues, heart tissues, encephalum, and GI tract. This study aims to examine a wide variety of nanoparticles, focusing on their manufacturing methods, functional characteristics, and interactions within biological systems. Particular attention will be directed towards assessing the toxicity of nanoparticles in different organs and physiological systems, yielding a thorough comprehension of their potential health hazards and the processes that drive nanoparticle-induced toxicity. This analysis will also emphasize recent developments in nanoparticle applications and safety assessment methodologies.

Single-Molecule Detection of Serum MicroRNAs for Medulloblastoma with Biphasic Sandwich Hybridization-Assisted Plasmonic Resonant Scattering Imaging

MicroRNA (miRNA) dysregulation is closely related to the occurrence and progression of medulloblastoma (MB). However, the full potential of serum circulating miRNAs in MB diagnosis is restricted by their ultralow abundance in peripheral blood due to blood-brain barrier. Here, we report the direct preamplification-free detection of aberrant expression of oncogenic miRNAs in serum from MB patients by proposing a simple yet robust single-molecule assay that combines biphasic sandwich hybridization in nucleic acids and the dark-field single-particle plasmonic imaging (B2S2PI). In this strategy, signal DNA was prehybridized with target miRNA in homogeneous solution to form sDNA-RNA complexes. Then the captured DNA strands with rationally adjusted surface densities could efficiently capture the sDNA-RNA complexes to generate a well-separated DNA-RNA sandwich structure. The combination of homogeneous and heterogeneous reactions enabled interface-mediated hybridization reactions to maintain molecular stability with fewer bases, making it suitable for the direct amplification-free assays of short miRNA targets. Labeling the DNA-RNA hybrids with plasmatic gold nanotags allowed nondestructive recognition and imaging of individual miRNA targets under mild conditions with high signal-to-noise ratio. By digitally counting and analyzing the bright plasmonic resonant scattering spots, B2S2PI enabled both the measurement of a low femtomolar concentration of circulating miRNA-21 in 5 μL sample volume within a turnaround of 2 h and the discrimination of single base mismatches. Moreover, B2S2PI was universal for detecting miRNAs with different sequences and secondary structures. Further analysis of clinical serum samples revealed that B2S2PI was capable of accurately distinguishing MB patients from noncancer controls with an area under the curve (AUC) of 0.99, which was superior to that of qRT-PCR. B2S2PI holds promise as a novel alternative means for single-molecule miRNA assay and sheds light on the circulating nucleic acid-based liquid biopsy of intracranial malignant tumors.

Optimization of nanoparticle-enhanced laser-induced breakdown spectroscopy for the hyperspectral chemical mapping of solid samples

BACKGROUND

Nanoparticle-enhanced laser-induced breakdown spectroscopy (NE-LIBS) uses the plasmonic effect of metallic nanoparticles deposited on solid sample surfaces to achieve a significant signal enhancement by lowering the breakdown threshold and elevating plasma temperature. NE-LIBS has been used for localized analysis, but NE-LIBS mapping of solids has rarely been done, due to several challenges. In this study, we scrutinized the performance of NE-LIBS hyperspectral mapping of solid samples, when the controlled deposition of nanoparticles was done using magnetron sputtering.

RESULTS

We performed a detailed optimization of the nanoparticle-related signal enhancement involving the laser wavelength, laser fluence and detector gating. It was confirmed that while the laser wavelength has only a small influence in the studied range (at 266 nm, 532 nm and 1064 nm), but there is an optimum for laser fluence and detection gate delay. The best signal enhancement achieved for a glass sample was 25-30. The applicability of the approach was demonstrated by hyperspectral NE-LIBS mapping of a granite rock sample, which provided an improved sensitivity in the study of the elemental distribution (exemplified for Li and Mg), and by paint linear discriminant analysis, in which NE-LIBS gave rise to a significantly improved accuracy (98 %, as opposed to the LIBS accuracy of only 84 %).

SIGNIFICANCE

The analytical benefits of NE-LIBS hyperspectral mapping was demonstrated in two applications involving industrially relevant sample types. For example, the enhanced signals in rock elemental mapping can improve the localization of mineral grains viable for economic mining. The qualitative discrimination application involving paints demonstrates that the NE-LIBS approach can be beneficial in the spatial classification or identification of the local quality of a solid sample surface.

Insight into Preventing Global Dengue Spread: Nanoengineered Niclosamide for Viral Infections

Millions of cases of dengue virus (DENV) infection yearly from Aedes mosquitoes stress the need for effective antivirals. No current drug effectively combats dengue efficiently. Transient immunity and severe risks highlight the need for broad-spectrum antivirals targeting all serotypes of DENV. Niclosamide, an antiparasitic, shows promising antiviral activity against the dengue virus, but enhancing its bioavailability is challenging. To overcome this issue and enable niclosamide to address the global dengue problem, nanoengineered niclosamides can be the solution. Not only does it address cost issues but also with its broad-spectrum antiviral effects nanoengineered niclosamide offers hope in addressing the current health crisis associated with DENV and will play a crucial role in combating other arboviruses as well.