Gold nanoparticles: assembly, supramolecular chemistry, quantum-size-related properties, and applications toward biology, catalysis, and nanotechnology

Nanoparticles make the difference: bacteriocidic, biocompatibility and wound healing merits of laser-transferred metal nanoparticles

This study demonstrates the high bactericidal efficiency of silver (Ag) and copper (Cu) nanoparticles synthesized via the laser-induced forward transfer (LIFT) method. The antimicrobial effectiveness of these nanoparticles was confirmed against both Gram positive (S. aureus, L. monocytogenes) and Gram negative (P. aeruginosa, E. coli) bacterial biofilms in vitro (silica glass and CaF2 substrates), ex vivo (pig skin), and in vivo (mouse wounds). The LIFT method achieved minimal inhibitory and bactericidal concentrations (MIC and MBC) within the lower range of bibliographic data, attributed to the uniform 2D-like surface coverage and chemically clean nature of the nanoparticles. Furthermore, biocompatibility studies revealed low cytotoxicity of LIFT-generated Ag and Cu nanoparticles in human embryonic kidney (HEK293) cells. In vivo experiments on Balb/c mice demonstrated accelerated wound epithelialization without adverse inflammatory or allergic responses for NP-treated wounds compared to the untreated (control). Exposure to AgNPs and CuNPs did not affect the functional/behavioral status of mice. Future research will extend these findings by testing additional animal models and exploring multi-elemental nanoparticles to further elucidate the bactericidal mechanisms. This method can be implemented on the basis of portable laser systems for antibacterial treatment in the field.

Sensitive amperometric immunosensor for pathogen antigen based on MoS2@AuNPs assembling dual-peptide as bioprobes with significant dual signal amplification

It is crucial to timely and accurately identify the causative virus for early treatment and urgent prevention. Viral antigen detection can identify those people who are most likely at risk of spreading the disease, but most based on antibodies with limited stability and sensitivity. Peptides offer several advantages over antibodies, such as low cost, smaller size and good stability. The development of electrochemical immunoassay using specific peptide probes have the merits of good sensitivity and selectivity as well as good stability. Herein we report an amperometric immunosensor using peptides as capture probe and recognition probe. The molecular docking suggests that the two peptides of Pi (sequence: NFWISPKLAFALGGGKKKSC) and FK11 (sequence: WFLNDSELISML), bioscreened from phage display, bind to N-terminal domain of SARS-CoV-2 spike protein (SP). The peptide Pi is assembled on MoS2@AuNPs modified electrode to capture SARS-CoV-2 SP, which is recognized by peptide FK11-displayed phage to form Pi/SARS-CoV-2 SP/FK11-phage sandwich. Then anti-M13 phage conjugated horseradish peroxidase (HRP) (anti M13-HRP) was introduced to recognize the phage capsid protein pVIII to form M13 phage/anti M13-HRP to enrich thousands of HRP, which can further electrochemically catalyze H2O2 reduction at highly conductive MoS2@AuNPs at - 0.35 V. Then amperometric immunosensor was constructed with linear range of 0.1-5000 pg/mL SARS-CoV-2 SP and detection limit of 0.074 pg/mL. The sensor also has good selectivity, batch reproducibility and stability, capable of detecting down to 10 transducing units/mL SARS-CoV-2 pseudoviruses. This work represents the first example of dual-peptide probes based sandwich-type electrochemical immunosensor integrated with dual signal amplification, which may provide a cost-effective assay platform in detecting real SARS-CoV-2 viruses for early diagnosis. The flexible and modular strategy can be extended to develop other type biosensors for a wide range of applications.

Growth of Gold Dendritic Structures under the Coexistence of Hexadecyltrimethylammonium Ions (CTA+) and Ethanol

We investigated the growth of gold nano/micro-structures by reducing gold ions with ascorbic acid in a mixed solvent of ethanol and water containing hexadecyltrimethylammonium bromide (CTAB). The geometries of the gold structures were influenced by the ratio of ethanol to water and the concentrations of CTAB and NaBr. We observed gold dendrites exceeding 10 μm in size, which were composed of numerous needles of varying sizes, some as small as a few tens of nanometers. The gold dendrites were grown within 20 min, a shorter duration compared to previous reports. The overall size of the gold dendrites exhibited dependence on the concentration of Br-, allowing for smaller sizes of less than 10 μm. The micelles of CTA+ were essential for the growth of gold dendrites. The ethanol ratio altered the viscosity and surface tension of the solution, resulting in a variety of geometries. We measured the extinction spectra of the gold dendrites, which revealed that they exhibited a broadband optical response. Observations using a dark-field optical microscope showed that their plasmon resonances were predominantly in the red region. The Raman spectrum of para-aminothiophenol (p-ATP) was measured using the gold dendrites under 785 nm, which revealed field enhancement at the surface of the gold dendrites.

Unraveling the Influence of the Anchored Headgroup and Ligand Tail Group Length on the Self-Assembly of ZnO NCs at the Air-Water Interface

Understanding the self-assembly of nanocrystals into ordered superlattices is fundamental for tailoring nanoscale assembly and developing functional materials. However, the rational-by-design hierarchical assembly is complex, as it needs to orchestrate several physical and chemical processes. In this work, we investigate how the character of a ligand shell, particularly the type of anchored headgroup and the length of the ligand tail group, affects the self-assembly properties of nanoscale building blocks and the properties of corresponding thin films. Thus, a series of colloidal zinc oxide nanocrystals (ZnO NCs) coated with different organic shells are prepared by a self-supporting organometallic approach (OSSOM) and then self-assembled at the air-water interface. We demonstrate that ligands bearing fewer and longer alkyl chains attached to the headgroup promote a higher level of ligand interdigitation. This, in turn, leads to stronger interparticle interactions and enhanced viscoelastic properties of the resultant films. Shorter ligands and a more compact capping layer (more aliphatic chains per ligand) prevent interdigitation, allowing ZnO NCs to retain their individual character and form more elastic films. Our findings reveal the importance of organic shell design in the self-assembly of nanocrystals due to the steric control, and allow an extra level of tailorability to obtain the desired properties for the material called "superlattices" or "NC solids".

Green synthesis of gold nanoparticles from pomegranate juice ascertained by a combined approach based on MALDI FT-ICR MS and LC-ESI-MS/MS

This research employs advanced analytical techniques to explore the specific roles of Pomegranate Juice (PJ) phytochemicals in both the reduction and stabilization of gold nanoparticles (AuNPs) obtained by means of juice from wasted fruits. A level 3 for classes annotation, used for MALDI FT ICR-MS data, was useful to provide an immediate visualization of the main involved metabolites in AuNPs synthesis, through van Krevelen diagrams. More than 25 elemental formulae containing at least one Au atom were assigned to AuNPs sample, confirming the formation of organogold complexes. LC-MS/MS analysis allowed a level 2 annotation of polyphenols and carbohydrates involved in metal reduction and AuNPs surface coating. This work highlights the potential of PJ in green nanoparticles synthesis, providing insights into the bioactive compounds responsible for the tunable characteristics of AuNPs.

Rational development of fingolimod nano-embedded microparticles as nose-to-brain neuroprotective therapy for ischemic stroke

Ischemic stroke is one of the major diseases causing varying degrees of dysfunction and disability worldwide. The current management of ischemic stroke poses significant challenges due to short therapeutic windows and limited efficacy, highlighting the pressing need for novel neuroprotective treatment strategies. Previous studies have shown that fingolimod (FIN) is a promising neuroprotective drug. Here, we report the rational development of FIN nano-embedded nasal powders using full factorial design experiments, aiming to provide rapid neuroprotection after ischemic stroke. Flash nanoprecipitation was employed to produce FIN nanosuspensions with the aid of polyvinylpyrrolidone and cholesterol as stabilizers. The optimized nanosuspension (particle size = 134.0 ± 0.6 nm, PDI = 0.179 ± 0.021, physical stability = 72 ± 0 h, and encapsulation efficiency of FIN = 90.67 ± 0.08%) was subsequently spray-dried into a dry powder, which exhibited excellent redispersibility (RdI = 1.09 ± 0.04) and satisfactory drug deposition in the olfactory region using a customized 3D-printed nasal cast (45.4%) and an Alberta Idealized Nasal Inlet model (8.6%) at 15 L/min. The safety of the optimized FIN nano-embedded dry powder was confirmed in cytotoxicity studies with nasal (RPMI 2650 and Calu-3 cells) and brain related cells (SH-SY5Y and PC 12 cells), while the neuroprotective effects were demonstrated by observed behavioral improvements and reduced cerebral infarct size in a middle cerebral artery occlusion mouse stroke model. The neuroprotective effect was further evidenced by increased expression of anti-apoptotic protein BCL-2 and decreased expression of pro-apoptotic proteins CC3 and BAX in brain peri-infarct tissues. Our findings highlight the potential of nasal delivery of FIN nano-embedded dry powder as a rapid neuroprotective treatment strategy for acute ischemic stroke.

Chitosan-metal and metal oxide nanocomposites for active and intelligent food packaging; a comprehensive review of emerging trends and associated challenges

In recent years, significant advancements in biopolymer-based packaging have emerged as a response to the environmental challenges posed by traditional petroleum-based materials. The drive for sustainable, renewable, and degradable alternatives to fossil-based components in the packaging industry has led to an increased focus on chitosan, the second most abundant biopolymer after cellulose. Chitosan offers intrinsic properties such as biodegradability, biocompatibility, antimicrobial activity, excellent barrier and film-forming capabilities, positioning it as an ideal candidate for food packaging applications. However, limitations including inferior mechanical, thermal, barrier properties, and brittleness compared to conventional plastics have limiting its widespread adoption in the food packaging industry. Chitosan has been extensively utilized in various forms, particularly as nanocomposites incorporating metal nanoparticles, leading to chitosan-based nanocomposite films/coatings that synergistically combine the advantageous properties of both chitosan and metal nanoparticles. Through an in-depth analysis of the current research (primarily the last 5 years), this review delves into the physicochemical, mechanical, sensing, and antimicrobial properties of chitosan nanocomposite as an innovative food packaging material. This review will provide insights into the potential toxicity and environmental impact of nanoparticle migration, as well as the prospects and challenges associated with chitosan-metal/metal oxide nanocomposite films in the development of sustainable packaging solutions.

Light Entrapment by Plasmonic Chiral Lock for Enhancement of 2D Flakes Catalytic Activity

Plasmon-based triggering leads to an effective increase of material catalytic activity in a number of relevant photoelectrochemical transformations, including nitrogen reduction for the production of ammonia. The efficiency of the plasmon assistance can be significantly increased through the rational design of hybrid photoelectrodes, e.g., by placing a redox-active material at plasmonic hot spots that may arise between two coupled nanostructures. In this work, we describe the creation and utilization of chiral plasmon-active hybrid structures (based on the so-called gold helicoids) coupled with redox-active 2H-MoS2. The chiral plasmon-active gold nanoparticles (with the same or opposite chirality) were spatially separated by thin two-dimensional (2D) flakes to reach mutual plasmon coupling between them. Using numerical simulations and SERS measurements, the dependence of the local enhancement of the electric field (EF) inside the created plasmon-active diastereomer consisting of Au helicoid-2D MoS2-Au helicoid "sandwich structure", on the mutual chirality of the nanoparticles is demonstrated. It is found that the plasmon energy is more efficiently "concentrated" in the MoS2 space using the "chiral trap" of light energy (i.e., chiral plasmonic lock), even in the case where the chiral handedness of Au nanoparticles is matching. The created hybrid structures were subsequently used for nitrogen reduction and ammonia production proceeding on the MoS2 surface. A clear dependence of the catalytic activity of MoS2 on the matching or mismatching of Au helicoid chiralities (and related local value of EF) is observed. In particular, a two-time increase in the ammonia yield is obtained in the case of matching chirality, compared to that in the case of mismatched configuration or the control experiments performed with nonchiral Au nanocubes. Hence, the utilization of chiral plasmonic nanoparticles and their dimers (or multimers) provides an additional opportunity for even more effective photosensibilization of redox-active materials.

Elucidating Antibody Conjugation and Orientation Dynamics on Phenylalanine-Functionalized Gold Nanoparticles: The Role of Lipid Coating and Other Physiological Conditions

Gold nanoparticles (AuNPs) functionalized with antibodies offer significant potential to advance biomedical applications due to their unique optical properties and the specificity of antibody-antigen interactions. A critical aspect of optimizing these AuNP-based systems is the effective adsorption of antibodies on the nanoparticle surface. Recent research has focused on developing new strategies to enhance antibody loading and orientation, with the aim of improving antibody activity. However, the lack of robust analytical methods for accurately quantifying the activity of conjugated antibodies and comparing immobilization strategies remains a significant challenge. Herein, for the first time, we describe the effect of DPPC and DOPC lipid coatings on the interaction of phenylalanine functionalized gold nanoparticles (AuPhe NPs) with immunoglobulin G (IgG) antibody under varying pH (∼6, 7.4, and 9) and buffer systems (HEPES and phosphate). Using several techniques, we reveal the superior performance of lipid-coated AuPhe NPs, particularly those coated with DPPC, compared to native AuPhe NPs in terms of stability, antigen-binding activity, and antibody orientation. Between the two different buffer systems, antibody adsorption on AuPhe NPs is significantly higher in the zwitterionic buffer (HEPES) compared to the negatively charged phosphate buffer. Furthermore, at lower pH, native AuPhe NPs and DOPC-coated AuPhe NPs undergo aggregation, and DPPC-coated AuPhe NPs remain stable. Considering the vital role of lipid coatings under varying physiological conditions, we propose that lipid-coated AuPhe NPs serve as robust platforms for diverse biomedical applications, ensuring enhanced stability and efficiency in antibody-mediated processes.

Nanoparticles and Nanomaterials: A Review from the Standpoint of Pharmacy and Medicine

Nanoparticles (NPs) represent a unique class of structures in the modern world. In comparison to macro- and microparticles, NPs exhibit advantages due to their physicochemical properties. This has resulted in their extensive application not only in technical and engineering sciences, but also in pharmacy and medicine. A recent analysis of the scientific literature revealed that the number of articles related to the search term "nanoparticle drugs" has exceeded 65,000 in the last decade alone, according to PubMed. The growth of scientific publications on NPs and nanomaterials (NMs) in pharmacy demonstrates the rapidly developing interest of scientists in exploring alternative ways to deliver drugs, thereby improving their pharmacokinetic and pharmacodynamic properties, and the increased biocompatibility of many nanopharmaceuticals is a unique key to two mandatory pharmaceutical requirements-drug efficacy and safety. A comprehensive review of the literature indicates that the modern pharmaceutical industry is increasingly employing nanostructures. The exploration of their physicochemical properties with a subsequent modern approach to quality control remains the main task of modern pharmaceutical chemistry. The primary objective of this review is to provide a comprehensive overview of data on NPs, their physicochemical properties, and modern approaches to their synthesis, modification of their surface, and application in pharmacy.

Oriented gold nanorods on polyacrylic acid grafted carbon nanotube for efficient SERS detection of cationic dyes

In this work, we successfully achieved controllable assembly of gold nanorods (AuNRs) into end-to-end orientation using polyacrylic acid (PAA) grafted carbon nanotube (CNT) (i.e., CNT-g-PAA) as a template. The resulting CNT-g-PAA/AuNRs hybrid assemblies were prepared via electrostatic interactions between negnative PAA-grafted CNT and positive hexadecyltrimethylammonium bromide (CTAB)-capped AuNRs. Due to the anisotropic nature of AuNRs and one-dimensional structure of CNT, the end-to-end arrangement of AuNRs immobilized on the CNT-g-PAA results in enhanced uniaxial plasmon coupling and thus stronger SERS response, as compared to the 3D SiO2-g-PAA/AuNRs assemblies. In addition, PAA-functionalized CNTs ensure the predominantly end-to-end assembly of AuNRs on the CNT surface, which greatly enhances the structural stability of the assemblies. Moreover, the PAA brushes on the CNT surface contribute to the selective and efficient adsorption of cationic dyes on the SERS substrate surface. This enhancement has improved the sensitivity of the substrate, achieving detection limits for malachite green (MG) and crystal violet (CV) as low as 10-10 M. Our present strategy opens up an avenue for the fabrication of novel optically enhanced nanodevices.

Coumarin Derivative and Gold Nanoparticle Conjugate as a Selective Fluorescent Sensor for Mercury Ion in Real Sample

A biphenyl based coumarin fluorescent molecule, N,N'-bis(7-diethylamino-2-oxo-2 H-chromen-3-yl)methylene)biphenyl-2-2'-dicarbohydrazide (molecule 1) has been synthesized and characterised. Photophysical studies of 1 exhibit solvent polarity dependent absorption and emission maxima. Citrate capped gold nanoparticles (AuNPs) have been mixed with molecule 1 for the preparation of AuNPs/1 conjugate. The association constant of the AuNPs/1 conjugate has been calculated to 4.54 × 104 M- 1. The AuNPs/1 conjugate has been found to detect Hg2+ ion selectively by fluorescence enhancement. While addition of molecule 1 into the solution of AuNPs, fluorescence intensity of 1 quenched. On addition of several monovalent, divalent and trivalent metal ion into the solution of AuNPs/1 conjugate separately, there was no change in fluorescence intensity of 1 has been observed. However, upon addition of Hg2+ ion into the solution of AuNPs/1 conjugate, the fluorescence intensity enhancement occurred, indicating released of 1 from the surface of AuNPs and probably aggregation of AuNPs took place in presence of Hg2+ ion. The AuNPs/1 conjugate has been found to have a detection limit of 2.3 × 10- 9 M for Hg2+ ion in aqueous solvent. Meanwhile, the AuNPs/1 conjugate have also been successfully applied for the determination of Hg2+ in real water samples.

A colorimetric and surface-enhanced Raman scattering dual-mode "sandwich" immunosensor for ultrasensitive detection of Salmonella

Herein, a dual-mode approach combining colorimetry and surface-enhanced Raman scattering (SERS) were developed for Salmonella detection. Immunomagnetic beads were used to separate and concentrate the Salmonella. And the GOx@ZIF-90@PDA@pAbs were used as signal probe to catalyze glucose to form H2O2. In the presence of H2O2, tyramine (TYR) aggregation was brought on by HRP-catalyzed phenol polymerization, which led to the aggregation of AuNPs through the strong electrostatic interactions between TYR and AuNPs. Based on the enzymatic cascade catalyzed signal amplification induced AuNPs aggregation, the dual-mode method exhibited wide linear range (101-105 CFU/mL) and high sensitivity. The limit of detection (LOD) of colorimetric mode was 34 CFU/mL, while the LOD was 5 CFU/mL in SERS mode, which was 6.8-fold lower than that of colorimetric mode. Furthermore, the two modes demonstrated high specificity and applicability, which might be a promising method for rapid and sensitive detection of Salmonella to ensure food safety.

Synthesis, crystal structure, vibrational study, optical characterization, Hirshfeld surface analysis and dielectric studies of a new indium-based hybrid material formulated as [(C9H8N)2(InCl6)·2(H2O)]

A newly developed indium-based hybrid compound, [(C9H8N)2(InCl6)·2(H2O)], was successfully synthesized using a slow evaporation method at room temperature. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were employed to observe the morphology and chemical composition of the particles. Structural analysis was performed through crystal X-ray diffraction (SXRD) and powder X-ray diffraction (PXRD) and revealed that the studied material crystallized in the triclinic P1 space group. The atom packing in this structure was characterized by the presence of alternating organic and inorganic layers along the b-axis. These arrangements were stabilized through multiple hydrogen bonds and centroid-centroid stacking interactions occurring between nearly parallel organic cations. Vibrational and optical properties were also explored using FT-IR and UV-Vis methods, respectively. Additionally, thermal analysis was performed via TGA/DTA and DSC measurements to assess the thermal stability and phase transformation of the title compound. Analysis of the Hirshfeld surface was carried out to examine the interactions between molecules. This allowed a quantitative assessment of the relative contribution of these interactions in the crystal structure. AC conductivity measurements (10-6 Ω-1 cm-1) confirmed the semiconductor character of the compound. The conductivity mechanism was attributed to the correlated barrier hopping (CBH) mechanism. Furthermore, electrical modulus measurements demonstrated the presence of grain effects.

Development of a gold nanoparticle-based colorimetric sensor utilizing cysteine-loaded liposomes in acidic buffer solutions

This study presents the development of a colorimetric sensing system, utilizing gold nanoparticles (AuNPs) and cysteine (Cys)-encapsulated liposomes (CELPs) as sensing probes, that functions in a variety of buffer solutions. Triton X-100 (TX-100), a nonionic surfactant, was used to simulate a biological activity that disrupts the liposome membrane. The Cys released from the CELPs by TX-100 triggered the aggregation of AuNPs, causing a noticeable red-to-blue color change, which was enhanced by Cu2+ chelation. The AuNP-CELP/TX-100 system was tested at pH 5-7.4 in various buffers. At neutral pH (7.0-7.4), the system with citrate-capped AuNPs (cit-AuNPs) displayed a distinctive colorimetric response in the presence of Cu2+ (0.3 mM), transitioning from red to blue with a UV-vis absorption shift from 525 nm to approximately 660 nm. However, the cit-AuNPs showed a limited stability in acidic buffers, and cetyltrimethylammonium bromide (CTAB)-capped AuNPs (cit-AuNPs-CTAB) were employed as an alternative at acidic pH. Overall, the AuNP-CELP/TX-100 sensing system, utilizing the cit-AuNPs-CTAB and Cu2+ chelation to Cys, exhibited the potential to be an effective sensing method working in acidic media. The test results with TX-100, which disrupts the liposome membrane, suggest that this system can be used to visualize diverse biological interactions involving membrane disruption, such as viral attacks, in acidic solutions with diverse ionic compositions.

Carborane Meets Metal Nanocluster: New Opportunities in Nanomaterials

ConspectusMetal nanoclusters, distinguished by their atom-precise structures and quantum size effect, are regarded as a crucial bridge between organometallic complexes and plasmonic metal nanoparticles. These nanoclusters are primarily composed of a metallic core enveloped by protective ligands, wherein the ligands play a vital role in determining the nanoclusters' synthesis, structural integrity, and physicochemical properties. Considerable efforts in ligand engineering have concentrated on exploring novel coordinating functional groups to advance nanocluster research, particularly in the precise and controlled synthesis of superatomic nanoclusters, fine-tuning their intrinsic properties, and subsequent assembly and application. However, the backbone of these ligands seems equally important but attracts less attention. It is reasonable that if the utility of the two moieties (coordinating functional group and backbone) provokes a profound synergistic effect, their contributions to the structures and properties of the resultant metal nanoclusters are extremely inestimable. In this context, carborane, with its spherical shape and three-dimensional aromaticity (electronic effect), has emerged as a promising candidate for ligand backbone design. Over the past two decades, the incorporation of carborane moieties into ligands has enabled the construction of various metal nanoclusters exhibiting distinct architectures, enhanced stability, and unique reactivity. Therefore, it is important to present the current status and challenges associated with carboranyl ligand-protected metal nanoclusters to guide their future development. This Account provides a comprehensive summary of the recent advances in carboranyl ligand-stabilized metal nanoclusters, with a primary focus on the contributions from our laboratory. We begin by discussing the unique advantages of introducing carborane-based ligands in metal nanocluster preparation, with particular emphasis on their virtues for the synthesis of superatomic nanoclusters, heterometal-doped nanoclusters, and isostructural nanoclusters. Subsequently, we summarize the carborane-based ligand engineering strategies for precise modification and hierarchical assembly of metal nanoclusters, elucidating how the incorporation of carborane facilitates the modulation of specific properties and promotes supramolecular and covalent assembly. Furthermore, we discuss the cooperativity achieved by carboranyl ligands and the metal nanocluster framework to broaden the scope of applications for these nanoclusters in versatile fields, including hypergolic fuels, a previously unexplored area. Finally, we discuss the challenges facing future research on carboranyl ligand-protected metal nanoclusters, including the incorporation of nido-carborane or metallocarborane, a fundamental understanding of structure-property relationships, and potential applications such as boron neutron capture therapy and radionuclide extraction. This Account aims to stimulate interest in the unique attributes of carborane-based ligands and their corresponding metal nanoclusters among students and researchers across diverse disciplines, including chemistry, crystal engineering, and materials science.

Rational design of gold nanoparticle-based chemosensors for detection of the tumor marker 3-methoxytyramine

In this study, we combined computational modeling, simulations, and experiments to design gold nanoparticle-based receptors specifically tailored for the NMR detection of 3-methoxytyramine (3-MT), a prognostic marker for asymptomatic neuroblastoma. We used short steered MD simulations to rank a library of 100 newly functionalized, tripeptide-coated AuNPs for their ability to recognize 3-MT. Validation of the computational analysis was performed on a subset of synthesized tripeptide-coated nanoparticles, showing a strong correlation between the predicted and experimental affinities. Eventually, we tested the sensing performance using nanoparticle-assisted NMR chemosensing, a technique which relies on magnetization transfer within a nanoparticle-host/analyte-guest complex to isolate the sole NMR signals of the analyte. This approach led to the identification of novel chemosensors that exhibited better performance compared to existing ones, lowering the limit of detection below 25 μM and demonstrating the utility of this integrated strategy.

Comprehensive insights into pancreatic cancer treatment approaches and cutting-edge nanocarrier solutions: from pathology to nanomedicine

Pancreatic cancer is one of the most lethal malignancies worldwide. It is characterized by poor prognosis, high mortality, and recurrence rates. Various modifiable and non-modifiable risk factors are associated with pancreatic cancer incidence. Available treatments for pancreatic cancer include surgery, chemotherapy, radiotherapy, photodynamic therapy, supportive care, targeted therapy, and immunotherapy. However, the survival rates for PC are very low. Regrettably, despite efforts to enhance prognosis, the survival rate of pancreatic cancer remains relatively low. Therefore, it is essential to investigate new approaches to improve pancreatic cancer treatment. By synthesizing current knowledge and identifying existing gaps, this article provides a comprehensive overview of risk factors, pathology, conventional treatments, targeted therapies, and recent advancements in nanocarriers for its treatment, along with various clinical trials and patents that justify the safety and efficacy of innovative carriers for drug delivery systems. Ultimately, this review underscores the potential of these innovative formulations to improve outcomes and contribute significantly to the advancement of Pancreatic Cancer treatment. Together, these insights highlight nano-formulations as a promising frontier for effectively treating Pancreatic Cancer.

MUA-modified Au nanocluster-driven fluorescence sensor for chromatographic test strips-based visual detection of patulin

The relationship between human health and patulin (PAT) in the diet is a complex and intertwined one. The development of a sensing approach for the field detection of patulin is crucial, as the current approach lacks real-time detection capabilities and is costly in terms of material and technology. This paper presents a portable ratiometric fluorescence sensor that can be used to rapidly, accurately, and efficiently detect patulin in food items at the point of origin. The sensor employs a combination of sulfhydryl functionalized gold nanoclusters (MUA-AuNCs) and blue emission carbon dots (B-CDs), which have been engineered to serve as highly effective "on-off" nanoprobes. The modified sulfhydryl (SH) groups present on the gold clusters serve as specific recognition sites for patulin binding. The probes exhibit a discernible shift in hue, from orange-red to blue. The sensitivity detection limit (LOD) for patulin was found to be 0.019 μM, with a substantial linear correlation observed in the range of 0-2.2 μM. The objective of the combined chromatographic test strip and color recognition platform was to facilitate the sensitive, accurate, and real-time detection of patulin in foodstuffs, which is of paramount importance for the prevention of early disease. To facilitate rapid and straightforward preliminary testing of food security, it is anticipated that the integrated chromatographic strip ratiometric fluorescence sensing platform will be developed into portable home detection equipment.

Curcumin-Conjugated Gold Nanoparticles Modulate Oxidative Stress and Antioxidant Activity and Maintain Intestinal Histoarchitecture in Drosophila melanogaster Larvae

Embryonic development is highly sensitive to oxidative stress, which can disrupt homeostasis. A strategy for mitigating oxidative stress induced by gold nanoparticles (AuNPs) involves the development of nanoparticles functionalized with phytoantioxidants through green chemistry methods, which also enhances the bioavailability of these antioxidants. In this study, environmentally friendly AuNPs were synthesized using curcumin (AuNPs-C), characterized by a spherical shape, uniform size, and a diameter of 7.2 ± 1.2 nm. The effects of AuNPs-C on oxidative stress in Drosophila melanogaster (Canton-S strain) during embryonic development were investigated, focusing on antioxidant defenses, oxidative damage, and morphological changes in the gastrointestinal tract. Exposure of Drosophila eggs to 50-200 μg/mL of AuNPs-C had no effect on hatching rates or pupal/adult development, with eclosion rates remaining above 50%. AuNPs-C did not elevate reactive oxygen species levels or induce lipid and protein oxidation in larvae exposed to 200 μg/mL. Oxidized protein products and malondialdehyde (MDA) levels remained comparable to those of the control group (70 ± 3 μM chloramine-T eq and 0.8 ± 0.1 nM MDA eq, respectively). Although AuNPs-C did not affect catalase activity or glutathione content, it reduced superoxide dismutase activity by 67% ± 6%. Additionally, AuNPs-C did not cause any damage to the gastrointestinal tract or alter the gut permeability of third-instar larvae. This study offers a deeper understanding of how AuNPs-C influence oxidative stress and antioxidant defense mechanisms in animal development and provides a basis for assessing the safety of phytoantioxidant-functionalized nanoparticles in vivo.

Enhanced Removal of Ultratrace Levels of Gold from Wastewater Using Sulfur-Rich Covalent Organic Frameworks

In view of the increasing global demand and consumption of gold, there is a growing need and effort to extract gold from alternative sources besides conventional mining, e.g., from water. This drive is mainly due to the potential benefits for the economy and the environment as these sources contain large quantities of the precious metal that can be utilized. Wastewater is one of these valuable sources in which the gold concentration can be in the ppb range. However, the effective selective recovery and recycling of ultratrace amounts of this metal remain a challenge. In this article, we describe the development of a covalent imine-based organic framework with pores containing thioanisole functional groups (TTASDFPs) formed by the condensation of a triazine-based triamine and an aromatic dialdehyde. The sulfur-functionalized pores served as effective chelating agents to bind Au3+ ions, as evidenced by the uptake of more than 99% of the 9 ppm Au3+ solution within 2 min. This is relatively fast kinetics compared with other adsorbents reported for gold adsorption. TTASDFP also showed a high removal capacity of 245 mg·g-1 and a clear selectivity toward gold ions. More importantly, the material can capture gold at concentrations as low as 1 ppb.

Next-Generation Metal-Organic Frameworks: Shaping the Future of Steroid Compound Management

Metal-Organic Frameworks (MOFs), as a new type of porous material, have attracted widespread attention in the fields of chemistry, materials science, and biomedicine owing to their unique structural characteristics and potential for functionalization. This review summarizes the latest research progress of MOFs in the field of steroid compounds, including the latest research progress of MOFs in the purification and separation of steroids, sensing and detection, catalytic transformation, and drug delivery. First, we explore how the porous structure and chemical functionalization of MOFs achieve efficient separation and purification of steroid compounds. Second, the high sensitivity and selectivity of MOFs as sensing materials in steroid detection, as well as their application potential in actual sample analysis, are analyzed. Furthermore, the role of MOFs in steroid catalytic transformation reactions is discussed, including their performance as catalysts or catalyst carriers. Finally, we focus on the innovative applications of MOFs in drug delivery systems, especially their advantages in controlled release and targeted drug delivery. This article also explores the future development trends and application prospects of MOFs in the field of steroids, highlighting the challenges and opportunities in material design, functionalization strategies, and practical implementations. Through this review, we aim to provide a comprehensive theoretical basis and practical guidance for further research and application of MOFs in the field of steroids.

Self-Assembled Peptide-Gold Nanoparticle 1D Nanohybrids Functionalized with GHK Tripeptide for Enhanced Wound-Healing and Photothermal Therapy

Glycyl-l-histidyl-l-lysine (GHK) tripeptides are known for their remarkable therapeutic potential, including wound-healing, anti-inflammatory activity, and cellular regeneration. However, their clinical application has been significantly hindered by poor biological stability and limited efficacy in a physiological medium. In this study, we introduce a sophisticated approach to overcome these limitations by developing supramolecular peptide nanofiber-gold (Au) nanoparticle (NP) hybrids functionalized with GHK tripeptides. By strategically manipulating peptide self-assembly and NP integration, we demonstrated a useful platform that enhances both therapeutic efficacy and material stability. Our methodology involves the precise engineering of 9-fluorenylmethoxycarbonyl-diphenylalanine scaffolds with GHK and KHG tripeptides, enabling robust nanofibril formation through π-π stacking and hydrogen bonding. Critically, we discovered that the specific amino acid sequence significantly influences the surface exposure of lysine, directly impacting the nanohybrid's wound-healing capabilities. The resultant nanohybrids exhibit exceptional characteristics: Au NPs are spatially confined within the peptide nanofibers, achieving a remarkably uniform size distribution of approximately 3 nm. These nanohybrids demonstrate superior near-infrared (NIR) light absorption and photothermal conversion efficiency, enabling effective eradication of cancer cells and organoids killing under NIR irradiation. This dual-functional nanohybrid integrates biocompatible and enzymatically degradable peptide scaffolds to achieve synergistic wound-healing and cancer-killing effects. By mitigating the cytotoxicity and biodegradability issues associated with conventional photothermal agents, our system provides a promising strategy to improve postoperative cancer therapy and promote tissue regeneration. This work highlights the potential of peptide-inorganic nanohybrids in advancing multifunctional therapeutic platforms for cancer treatment and tissue repair.

Landscape of small nucleic acid therapeutics: moving from the bench to the clinic as next-generation medicines

The ability of small nucleic acids to modulate gene expression via a range of processes has been widely explored. Compared with conventional treatments, small nucleic acid therapeutics have the potential to achieve long-lasting or even curative effects via gene editing. As a result of recent technological advances, efficient small nucleic acid delivery for therapeutic and biomedical applications has been achieved, accelerating their clinical translation. Here, we review the increasing number of small nucleic acid therapeutic classes and the most common chemical modifications and delivery platforms. We also discuss the key advances in the design, development and therapeutic application of each delivery platform. Furthermore, this review presents comprehensive profiles of currently approved small nucleic acid drugs, including 11 antisense oligonucleotides (ASOs), 2 aptamers and 6 siRNA drugs, summarizing their modifications, disease-specific mechanisms of action and delivery strategies. Other candidates whose clinical trial status has been recorded and updated are also discussed. We also consider strategic issues such as important safety considerations, novel vectors and hurdles for translating academic breakthroughs to the clinic. Small nucleic acid therapeutics have produced favorable results in clinical trials and have the potential to address previously "undruggable" targets, suggesting that they could be useful for guiding the development of additional clinical candidates.

Density and structure of DNA immobilised on gold nanoparticles affect sensitivity in nucleic acid detection

Gold nanoparticles (AuNPs) are used as colorimetric biosensors that, combined with immobilised single-stranded DNA (ssDNA-AuNPs), can be used in genetic diagnosis because of their rapid and sequence-specific aggregation properties. Herein, we investigated the effect of the steric structure and density of immobilised DNA on AuNPs in non-crosslinking aggregation-based nucleic acid detection. Detection sensitivity improved with decreasing DNA density for linear conformations, but worsened for those with more rigid stem structures. We controlled the density of immobilised DNA using two different methods and investigated the aggregation behaviour of ssDNA-AuNPs. Interestingly, controlling the immobilised DNA density through ethylene glycol treatment had different effects on ssDNA-AuNP aggregation compared to those of alkanethiol substitution. This study suggests that the sensitivity of ssDNA-AuNPs for detecting target DNA could be affected by density and structure of the immobilised DNA.

Green Synthesis and Characterization of Silver and Gold Nanoparticles Using Echinophora platyloba Extract and Evaluation of Their Anti-Inflammatory and Antioxidant Properties

This study intends to investigate the green synthesis of silver (Ag) and gold (Au) nanoparticles (NPs) using Echinophora platyloba extract and to evaluate the antioxidant and anti-inflammatory effects of the synthesized NPs and the extract. In this study, aqueous and hydroalcoholic extracts of E. platyloba were prepared, which were used for the biosynthesis of Ag and Au NPs. Dynamic light scattering (DLS), zeta potential analysis, transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, UV-Vis spectroscopy, and X-ray diffraction (XRD) methods were used to characterize the green NPs. The antioxidant effect of the NPs was estimated using in vitro methods, including reducing power (RP), ferric reducing/antioxidant power (FRAP), and 2,2-diphenyl-1-picrylhydrazyl (DPPH). To evaluate the anti-inflammatory and antioxidant activity of E. platyloba extract and Ag and Au NPs, we used the carrageenan method. In our experiment, the extract and the synthesized NPs were administered orally to the mice 2 h before the carrageenan injection. The subsequent inhibition of inflammation and reduction of paw thickness were quantified. To evaluate their antioxidant effect, malondialdehyde (MDA), and total antioxidant capacity (TAC) levels were measured. Levels of pro-inflammatory cytokines, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), were also quantified. In this study, the results indicate that the synthesized Ag and Au NPs have antioxidant and anti-inflammatory effects. The most promising results were observed in the groups that received the Ag NPs.

Recent advances in nanomaterials for the detection of mycobacterium tuberculosis (Review)

The world's leading infectious disease killer tuberculosis (TB) has >10 million new cases and ~1.5 million mortalities yearly. Effective TB control and management depends on accurate and timely diagnosis to improve treatment, curb transmission and reduce the burden on the medical system. Current clinical diagnostic methods for tuberculosis face the shortcomings of limited accuracy and sensitivity, time consumption and high cost of equipment and reagents. Nanomaterials have markedly enhanced the sensitivity, specificity and speed of TB detection in recent years, owing to their distinctive physical and chemical features. They offer several biomolecular binding sites, enabling the simultaneous identification of multiple TB biomarkers. Biosensors utilizing nanomaterials are often compact, user‑friendly and well‑suited for detecting TB on location and in settings with limited resources. The present review aimed to review the advances that have occurred during the last five years in the application of nanomaterials for TB diagnostics, focusing on their detection capabilities, structures, working principles and the significance of key nanomaterials. The current review addressed the limitations and challenges of nanomaterials‑based TB diagnostics, along with potential solutions.

Advancing Frontiers: Graphene-Based Nano-biosensor Platforms for Cutting-Edge Research and Future Innovations

Graphene and its derivatives have excellent electrical, mechanical, and optical capabilities, making it the perfect foundation for sensing living things. Graphene-based nano biosensors have shown exceptional sensitivity, selectivity, and quick response times when used to detect a range of analytes, such as biomolecules, cells, and pathogens. The main uses of graphene-based nano biosensors are disease diagnosis, environmental monitoring, food safety, and drug development. It also explores prospective future strategies, such as methods for functionalizing nanomaterials, their incorporation with other nanomaterials, and the creation of wearable and implantable gadgets. Various signalling techniques, such as fluorescence, electrochemistry, surface plasmon resonance, surface-enhanced Raman scattering, etc., can be coupled with graphene-based biosensors to quantitatively detect disease-associated DNA, RNA, and protein biomarkers quantitatively. Graphene-based nano biosensors, combined with cutting-edge innovations like artificial intelligence and the Internet of Things, can completely transform industries like healthcare and environmental monitoring. Developing these biosensors with high sensitivity and low detection limits provides a new direction in medical and personal care. The later portion of the review covers the difficulties, prospective fixes, and opportunities of graphene-based biosensors.

Advancements in Mercury-Free Electrochemical Sensors for Iron Detection: A Decade of Progress in Electrode Materials and Modifications

Efforts to quantify iron ion concentrations across fields such as environmental, chemical, health, and food sciences have intensified over the past decade, which drives advancements in analytical methods, particularly electrochemical sensors known for their simplicity, portability, and reliability. The development of electrochemical methods using non-mercury electrodes is increasing as alternatives to environmentally unsafe mercury-based electrodes. However, detecting iron species such as Fe(II) and Fe(III) remains challenging due to their distinct chemical properties, continuous oxidation-state interconversion, presence of interfering species, and complex behavior in diverse environments and matrixes. Selective trace detection demands careful optimization of electrochemical methods, including proper electrode materials selection, electrode surface modifications, operating conditions, and sample pretreatments. This review critically evaluates advancements over the past decade in mercury-free electrode materials and surface modification strategies for iron detection. Strategies include incorporating a variety of nanomaterials, composites, conducting polymers, membranes, and iron-selective ligands to improve sensitivity, selectivity, and performance. Despite advancements, achieving ultra-low detection limits in real-world samples with minimal interference remains challenging and emphasizes the need for enhanced sample pretreatment. This review identifies challenges, knowledge gaps, and future directions and paves the way for advanced iron electrochemical sensors for environmental monitoring, health diagnostics, and analytical precision.

Navigating translational research in nanomedicine: A strategic guide to formulation and manufacturing

Over the past two decades, extensive research has focused on both the fundamental and applied aspects of nanomedicine, driven by the compelling advantages that nanoparticles offer over their bulk counterparts. Despite this intensive research effort, fewer than 100 nanomedicines have been approved by the U.S. Food and Drug Administration and the European Medicines Agency since 1989. This disparity highlights a substantial gap in translational research, reflecting the disconnect between the prolific research in nanomedicine and the limited number of products that successfully reach and sustain themselves in the market. For instance, the nanomedicine DepoCyt, which received FDA approval in 1999 for the treatment of lymphomatous meningitis, was discontinued in 2017 due to persistent manufacturing issues. To address similar translational challenges, this review aims to identify and analyse issues related to the formulation design and manufacturing of nanomedicines. It provides an overview of the most prevalent manufacturing technologies and excipients used in nanomedicine production, followed by a critical evaluation of their clinical translatability. Furthermore, the review presents strategies for the rational formulation design and optimization of nanomedicine manufacturing, adhering to the principles of quality-by-design and quality risk management.

Rapid and Sustainable Electrochemical Pd Catalyst Generation from Bulk Metal

Palladium catalysts constitute a cornerstone of modern chemistry with upmost scientific and industrial impact. Bulk palladium metal itself is chemically inert, and a sequence of chemical transformations has to be utilized to convert the metal into a Pd precatalyst covered by ligands. However, the "cocktail" concept of catalysis discovered recently has shown that Pd systems can efficiently operate in catalysis without the need for a complicated and expensive preinstalled ligand environment. Here, we point out on a green and sustainable process for the generation of Pd active species without the need for waste-abundant precatalyst-related chemistry. In this work, an electric current was used to generate an active Pd catalyst from a bulk metal in an ionic liquid medium for the efficient cross-coupling of aryl iodides/bromides and boronic acids. A synthetically important Suzuki cross-coupling was utilized as a representative test reaction to confirm the idea. Notably, an electric current is used only at the Pd dissolution stage. Afterwards, the electrodes are removed from the reaction mixture, and a standard reaction procedure can be followed. The reported catalyst preparation process via electrochemical dissolution is potentially compatible with several already existing catalytic methods.

Copper Nanoparticles Synthesized by Chemical Reduction with Medical Applications

Copper nanoparticles (CuNPs) have attracted attention due to their low cost and high specific surface area. In this work, a simple and inexpensive two-step synthesis method was proposed to prepare highly stable and well-dispersed spherical CuNPs in solution with a particle size of approximately 37 nm. Synthesis of CuNPs was carried on in the presence of complexing agent trisodium citrate (TSC), while for the chemical reduction step, sodium borohydride (NaBH4) was used. Taking into account the potential of this type of nanoparticles, their synthesis and characterization represent a current and relevant topic in the field. The ability to control the size, shape and properties of CuNPs by adjusting the synthesis parameters (pH, precursor:stabilizer:reductant ratio, homogenization time, temperature) offers extraordinary flexibility in the development of these materials. The combination of characterization techniques such as SEM, EDX, UV-Vis, Raman, FT-IR and AFM provides a thorough understanding of the structure and properties of CuNPs, allowing the modulation of the properties of the obtained nanoparticles in the desired direction. Based on the studies, the copper reduction mechanism was proposed. For the theoretical verification of the size of the experimentally obtained spherical CuNPs, Mie theory was applied. A stability study of the synthesized CuNPs in optimal conditions was performed using UV-Vis analysis at specific time intervals (1, 3, 30 and 60 days), the sample being kept in the dark, inside a drawer at 25 °C. The CuNPs obtained after setting the optimal synthesis parameters (Cu(II):TSC:BH4+ = 1:1:0.2, pH = 5, homogenization time 60 min and temperature 25 °C) were then tested to highlight their antibacterial effect on some reference bacterial strains. The obtained CuNPs demonstrated very good antimicrobial efficacy compared to traditional antimicrobials, for both Gram-negative and Gram-positive bacteria. This may reduce the development of antimicrobial resistance, an urgent medical issue. After evaluating the cytotoxic effects of CuNPs on the SKBR3 cancer cell line, a significant decrease in cell proliferation was observed at the 0.5 mg/mL concentration, with a reduction of 89% after 60 h of cultivation. Higher concentrations of CuNPs induced a more rapid cytotoxic effect, leading to an accelerated decline in cell viability.

Simultaneous Guidance of Intraoperative Tumor Resection by Near-Infrared-II Imaging Combined with Complementary Surface-Enhanced Raman Imaging via Janus Au-PbS Nanoparticles

The development of sophisticated nanomaterials with synergistically enhanced functionalities and applications has been greatly promoted via the construction of Janus nanoparticles with controlled compositions. In this work, we described and demonstrated the formation of Janus Au-PbS nanoparticles (NPs) by Au NPs-mediated spontaneous epitaxial nucleation and growth. The mechanism of formation of Janus Au-PbS NPs was investigated in detail. Then, we also found that there was a strong electronic interaction between the Au NPs and PbS quantum dots (QDs) in Janus Au-PbS NPs, where electrons were transferred from the Au NPs domain to the PbS QDs domain. Moreover, the Janus Au-PbS NPs integrated the high-brightness tunable second near-infrared (NIR-II) photoluminescence emission and surface-enhanced Raman scattering (SERS), which achieved good intraoperative tumor resection. This complementary dual-functional imaging had the potential to enable more accurate tumor imaging and resection.

Glycan-Matchmade Multivalent Decoration of Enzyme Labels for Amplified Electrochemical Detection of Glycoproteins

Glycoproteins are of significant value to liquid biopsy of human diseases. Herein, we present a universal electrochemical platform for the amplified detection of glycoproteins, taking advantage of the glycan-matchmade multivalent decoration of enzyme labels for the enzymatic signal amplification. Briefly, the glycan-matchmade multivalent decoration involves two steps, i.e., the site-directed decoration of the phenylboronic acid-coated gold nanoparticles (PBA-AuNPs) to the cis-diol-containing glycans of glycoproteins and the subsequent decoration of enzyme labels via the affinity cross-linking between the glycan moieties of enzyme labels and the remaining PBA groups on the PBA-AuNP cross-linkers. As the glycan matchmaking-based strategy enables the decoration of each glycoprotein with multiple enzyme labels, this electrochemical platform exhibits a high sensitivity toward glycoprotein detection. Using alkaline phosphatase (ALP) as the proof-of-concept enzyme label in combination with the solid-state voltammetric stripping assay of the enzymatically deposited metallic silver, the detection limits at the pg mL-1 level have been obtained for the electrochemical aptamer-based detection of thrombin and prostate-specific antigen. Overall, this work illustrates an efficient and versatile strategy for the multivalent decoration of enzyme labels for electrochemical detection of glycoproteins at ultralow concentration levels, holding the desirable advantages of simplicity and cost-effectiveness over sandwich enzyme-linked immunosorbent assays.

Cydonia oblonga extract mediated biosynthesis of gold nanoparticles: Analysis of its anti-oral cancer and antioxidant properties

Here, using natural and biological macromolecules derived from Cydonia oblonga extract, we have developed a green protocol for the biogenic made Au NPs. Under ultrasonic activated conditions, the Cydonia oblonga phytomolecules were employed as an efficient green reducing agent for the Au3+ ions to the Au0 NPs. Additionally, by encapsulating or capping, they allowed the Au NPs to stabilize on their own. Several physicochemical techniques, such as elemental mapping, TEM, FE-SEM, UV-Vis spectroscopy, EDS, and ICP-OES, were used to analyze the structure of the Au NPs/Cydonia oblonga bio-nanocomposite. The field of medicinal therapeutics pertaining to human health includes cancer treatment as a major component. Subsequently, the as prepared Au NPs/Cydonia oblonga bio-nanocomposite was investigated for antioxidant and human anti-oral cancer assays. In such studies a number of cell lines, viz., HSC-3, HSC-2, and Ca9-22 were used in determining the cytotoxicity. Notably, Au NPs/Cydonia oblonga exhibit significant anti-oral cancer properties against HSC-3, HSC-2, and Ca9-22 cancer cell lines following time and dose-dependent manner. The corresponding IC50 values were determined as 201, 192, and 246 µg/mL respectively. DPPH radical scavenging method was used to determine the antioxidant activity of Au NPs/Cydonia oblonga bio-nanocomposite. The significant IC50 value suggested the material having very good antioxidant potential. The anti-human oral cancer effect of our material is believed to be due to its antioxidant effects.

Molecular-Scale Insights into the Heterogeneous Interactions between an m-Terphenyl Isocyanide Ligand and Noble Metal Nanoparticles

The structural and chemical properties of metal nanoparticles are often dictated by their interactions with molecular ligand shells. These interactions are highly material-specific and can vary significantly even among elements within the same group or materials with similar crystal structure. In this study, we surveyed the heterogeneous interactions between an m-terphenyl isocyanide ligand and Au and Ag nanoparticles (NPs) at the single-molecule limit. Specifically, we found that the ligation behavior with this molecule differs significantly between that of Au and AgNPs. Surface-enhanced Raman spectroscopy measurements revealed unique enhancement factors for two molecular vibrational modes between two metal surfaces, indicating different ligand binding geometries. Molecular-level characterization using scanning tunneling microscopy allowed us to directly visualize these variations between Ag and Au surfaces, which we assign as two distinct binding mechanisms. This molecular-scale visualization provides clear insights into the different ligand-metal interactions as well as the chemical behavior and spectroscopic characteristics of isocyanide-functionalized NPs.

New insights into gold nanoparticles in virology: A review of their applications in the prevention, detection, and treatment of viral infections

Viral infections have led to the deaths of millions worldwide and come with significant economic and social burdens. Emerging viral infections, as witnessed with coronavirus disease 2019 (COVID-19), can profoundly affect all aspects of human life, highlighting the imperative need to develop diagnostic, therapeutic, and effective control strategies in response. Numerous studies highlight the diverse applications of nanoparticles in diagnosing, controlling, preventing, and treating viral infections. Due to favorable and flexible physicochemical properties, small size, immunogenicity, biocompatibility, high surface-to-volume ratio, and the ability to combine with antiviral agents, gold nanoparticles (AuNPs) have shown great potential in the fight against viruses. The physical and chemical properties, the adjustability of characteristics based on the type of application, the ability to cross the blood-brain barrier, the ability to infiltrate cells such as phagocytic and dendritic cells, and compatibility for complexing with various compounds, among other features, transform AuNPs into a suitable tool for combating and addressing pathogenic viral agents through multiple applications. In recent years, AuNPs have been employed in various applications to fight viral infections. However, a comprehensive review article on the applications of AuNPs against viral infections has yet to be available. Given their versatility, AuNPs present an appealing option to address various gaps in combating viral infections. Hence, this review explores the attributes, antiviral properties, contributions to drug delivery, vaccine development, and diagnostic uses of AuNPs.

Citrus maxima extract-coated versatile gold nanoparticles display ROS-mediated inhibition of MDR-Pseudomonas aeruginosa and cancer cells

The expanding prevalence of microbial resistance to conventional treatments has triggered a race to develop alternative/improved strategies to combat drug-resistant microorganisms in an efficient manner. Here, the lethal impact of the biosynthesized gold nanoparticles (AuNPs) against multi-drug resistant (MDR) bacteria has been elucidated. AuNPs, synthesized from the extracts of the fruit, leaf and peel of the Citrus maxima plant, were physicochemically characterized by UV-Vis spectrophotometry, Dynamic Light Scattering (DLS), electron microscopy and spectroscopic techniques not only confirmed the production of AuNPs of size below 100 nm but also identified the phytochemicals adsorbed onto the surface of NPs. AuFeNP not only showed excellent antioxidant activity (∼95 % at 1 mg/mL) but also exhibited a commendable antimicrobial activity against MDR-Pseudomonas aeruginosa as assessed by the zone of inhibition (13.5 mm) and microwell broth dilution assays (9.5 μg/mL, MIC). Transmission electron microscopy (TEM) displayed bacterial cell membrane destruction post-AuNPs exposure. The killing mechanism of AuNPs elucidated the permeabilization of the cell membrane and generation of reactive oxygen species (ROS), ∼10-fold high depletion of GSH, and eventually leaching protein out of the cell. DNA damage, as a marker of apoptosis, was also noticed, which could be an implication of ROS accumulation in MDR-PA. AuNPs displayed significant toxicity at ∼ 10 μg/mL on various cancer cells (HT-1080, MRC-5, MDA-MB-231 and B16-F10) and relatively low toxicity on normal cells (MRC-5 and HaCaT). Scratch assay to identify the migration capability of breast cancer cells on treatment with AuNPs deciphered hampering of migration potential of breast cancer cells. Apoptotic topographies in B16-F10 cells were confirmed using AO/EtBr dual dye staining, DNA fragmentation, Caspase-3 assay and cell cycle analysis using flow cytometry. Hemolysis revealed minimal toxicity of AuNPs on human red blood cells. Nominal toxicity (∼70 % survival at 500 μg/mL of AuNPs) on mammalian cells was evaluated using Cell Titer-Glo cell viability assay. Overall results advocate the promising potential of biosynthetic AuFeNP against multi-drug-resistant pathogens and for further formulation into anticancer agents.

Water as Solvent for the Dispersion of 2D Nanostructured Materials

The development of large number of two-dimensional (2D) nanostructured materials that followed the success of graphene and the need for their handling and manipulation e. g., in inks, brought to the fore the study of solvents and substances that contribute to the stabilization of 2D nanomaterials in the liquid phase. The successful dispersion of 2D materials in solvents is combined with one of the most widespread preparation methods, that of liquid phase exfoliation. In this article, a review for the role of water in the preparation of different 2D nanostructures and their stable dispersions in the liquid phase is discussed. The use of water as a solvent or dispersant is instrumental in promoting materials with an ecological footprint, low cost, and sustainability.

Role of polymer graft stiffness in electrostatic-driven self-assembly of nanoparticles in solutions

Self-assembly of nanoparticles (NPs) in solution has garnered tremendous attention among researchers because of their electrical, chemical, and optoelectronic properties at the macroscale with potential applications in bio-imaging, bio-medicine, and therapeutics. Control of size, shape, and composition at the nanoscale is important in tuning the material's bulk properties. The grafting of NPs with polymers enables us to tune such bulk material properties at the nano level by controlling their assemblies, especially in solutions. The stiffness of grafts plays a crucial role in tuning the self-assembly of spherical NPs grafted with polyions (PGNs). Many recent studies based on single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA) showed the potential applications of such assemblies. In this work, we have performed coarse-grained molecular dynamics (MD) simulations to understand the charge-driven self-assembly of PGNs by varying stiffness of polymer grafts, the grafting density, and graft length. Self-assembly of these PGNs leads to the formation of different structures driven by the rigidity of polyion chains and the electrostatic interactions. A dramatic change in morphological transitions can be achieved, ranging from rings, strings, and percolated structures and ordered to disordered aggregates by tuning the control parameters. The percolated structures form disordered structures upon annealing with potential applications in thermal under filling, neuromorphic devices, and biological systems including drug delivery, and therapeutics.

Preparation of Diosgenin-Functionalized Gold Nanoparticles: From Synthesis to Antitumor Activities

Cancer ranks among the top causes of illness and death globally. Nanotechnology holds considerable promise for enhancing the effectiveness of therapeutic and diagnostic approaches in cancer treatment. Our study presents a promising strategy for applying thiocompound nanomedicine in cancer therapy. Our first study aimed to investigate the biological properties of a new compound thiodiosgenin (TDG)-a new derivative of diosgenin-a natural compound with known antioxidant and anticancer properties. Our current second study aimed to compare the therapeutic efficacy of a new diosgenin-functionalized gold nanoparticles-with its precursor on prostate cancer (DU-145) cell lines. Moreover, the safety of the new thio-derivative and new conjugates was tested against the human epithelial line PNT-2. New advanced analytical techniques were developed for the characterization of nanomaterials using methods such as SP-ICP-MS, UV-Vis, TEM, NMR, FT-IR ELS, and TGA. Our synthetic approach was based, on the one hand, on the ligand exchange of citrates to thiodiosgenin (TDG) on gold nanoparticles, and on the other hand, on the attachment of DG through an ester bond to the linker, which was 3-mercaptopropionic acid (MPA) on gold nanoparticles. Initial in vitro studies indicate that TDG shows greater cytotoxic effects on cancer cells but poses risks to normal prostate epithelial cells (PNT-2). It was demonstrated that all the conjugates produced exhibited significant cytotoxic effects against cancer cells while being less harmful to normal prostate epithelial cells (PNT-2) compared to TDG itself. All the obtained conjugates showed antitumor properties; however, for targeted transport, the system referred to as AuNPs-MPAm1-DG is promising, due to the size of the nanoparticles of 53 nm, zeta potential of -30 mV, and loading content of 27.6%. New methods for synthesizing conjugates with diosgenin were developed and optimized for medical applications. Advanced new analytical methodologies were developed to characterize new conjugates, particularly the use of SP-ICP-MS, to solve existing differences in the shape and morphology of the surface of new conjugates.

Nano-biopesticide formulation comprising of silver nanoparticles anchored to Ocimum sanctum: a sustainable approach to pest control in jute farming

The jute hairy caterpillar, Spilosoma obliqua (Lepidoptera: Erebidae) is considered as one of the major threats to jute cultivation. The best eco-friendly methods to combat these jute pests involve administration of nano-biopesticides, as a successful alternative to the toxic chemicals. In this study, a nano-biopesticide formulation containing green synthesized silver nanoparticles (Ag NPs) using Ocimum sanctum leaf extract has been proposed. The characterization studies confirmed significant interactions between the Ag NPs and bioactive components in the nano-biopesticide formulation. The comparative analysis of the aforementioned larval mortality showed better responses in the nano-biopesticide formulation rather than the crude (pure) leaf extract. The LC50 values were calculated both for the nano-biopesticide formulation and pure extract after 24, 48 and 72 h of treatment. The nano-biopesticide formulation was found to exhibit the lowest and much promising LC50 value of 93.21 ppm, 23.38 ppm, 5.96 ppm relative to that of LC50 values of 1590.74 ppm, 459.30 ppm, 102.68 ppm respectively for the crude leaf extract. The synergistic interactions between the components in the nano-biopesticide formulation can be associated with its greater effectiveness as a promising toxicant to the larvae of the jute caterpillar compared to the mere leaf extract, thereby, demonstrating a greener and safer method for effective pest management.

Surface Functionalization of Nanocarriers with Anti-EGFR Ligands for Cancer Active Targeting

Active cancer targeting consists of the selective recognition of overexpressed biomarkers on cancer cell surfaces or within the tumor microenvironment, enabled by ligands conjugated to drug carriers. Nanoparticle (NP)-based systems are highly relevant for such an approach due to their large surface area which is amenable to a variety of chemical modifications. Over the past decades, several studies have debated the efficiency of passive targeting, highlighting active targeting as a more specific and selective approach. The choice of conjugation chemistry for attaching ligands to nanocarriers is critical to ensure a stable and robust system. Among the panel of cancer biomarkers, the epidermal growth factor receptor (EGFR) stands as one of the most frequently overexpressed receptors in different cancer types. The design and development of nanocarriers with surface-bound anti-EGFR ligands are vital for targeted therapy, relying on their facilitated capture by EGFR-overexpressing tumor cells and enabling receptor-mediated endocytosis to improve drug accumulation within the tumor microenvironment. In this review, we examine several examples of the most recent and significant anti-EGFR nanocarriers and explore the various conjugation strategies for NP functionalization with anti-EGFR biomolecules and small molecular ligands. In addition, we also describe some of the most common characterization techniques to confirm and analyze the conjugation patterns.

Shape-Dependent Locomotion of DNA-Linked Magnetic Nanoparticle Films

The shape-dependent aero- and hydro-dynamics found in nature have been adopted in a wide range of areas spanning from daily transportation to forefront biomedical research. Here, we report DNA-linked nanoparticle films exhibiting shape-dependent magnetic locomotion, controlled by DNA sequences. Fabricated through a DNA-directed layer-by-layer assembly of iron oxide and gold nanoparticles, the multifunctional films exhibit rotational and translational motions under magnetic fields, along with reversible shape morphing via DNA strand exchange reactions. Notably, the shape of the film significantly influences its magnetic responsiveness, attributable to shape-dependent drag forces acting on mesoscopic films. The distinctive shape dependence combined with the shape-changing capability offers an approach to regulate magnetic locomotion within a constant magnetic field, as demonstrated here through the go and stop motion of nanoparticle films without altering the magnetic field.

Plasma-induced nanogap narrowing and morphological transformation in gold nanoparticle assemblies

The plasmonic properties of gold nanoparticle (AuNP) assemblies are critically influenced by the nanogaps between particles. Here, we demonstrate that plasma treatment effectively narrows these nanogaps and ultimately merges the nanoparticles. This process induces a sequential redshift, weakening, broadening, and an eventual blueshift of the plasmon coupling peak in UV-vis spectra, indicating transitions from classical to quantum regimes and finally to contact modes. Surface-enhanced Raman spectroscopy reveals an initial increase in intensity as the nanogaps narrow, followed by a decline as linker molecules are removed. Transmission electron microscopy images further show significant deformation of AuNPs after 5 min of plasma treatment. Based on these combined observations, we propose that the oxidative desorption of thiol linkers causes the collapse of self-assembled monolayers, leading to the gradual narrowing of nanogaps and eventual particle fusion. This plasma-induced transformation also enables the creation of novel AuNP shapes, such as nano-snowmen and particles with protruding morphologies, by merging heterodimers or core-satellite structures. Our findings not only deepen the understanding of plasma effects on nanoparticle assemblies but also expand the utility of plasma treatment for controlling nanogap distances and fabricating exotic nanoparticle shapes.

Biohybrid nano-platforms manifesting effective cancer therapy: Fabrication, characterization, challenges and clinical perspective

Nanotechnology-based delivery systems have brought a paradigm shift in the management of cancer. However, the main obstacles to nanocarrier-based delivery are their limited circulation duration, excessive immune clearance, inefficiency in interacting effectively in a biological context and overcoming biological barriers. This demands effective engineering of nanocarriers to achieve maximum efficacy. Nanocarriers can be maneuvered with biological components to acquire biological identity for further regulating their biodistribution and cell-to-cell cross-talk. Thus, the integration of synthetic and biological components to deliver therapeutic cargo is called a biohybrid delivery system. These delivery systems possess the advantage of synthetic nanocarriers, such as high drug loading, engineerable surface, reproducibility, adequate communication and immune evasion ability of biological constituents. The biohybrid delivery vectors offer an excellent opportunity to harness the synergistic properties of the best entities of the two worlds for improved therapeutic outputs. The major spotlights of this review are different biological components, synthetic counterparts of biohybrid nanocarriers, recent advances in hybridization techniques, and the design of biohybrid delivery systems for cancer therapy. Moreover, this review provides an overview of biohybrid systems with therapeutic and diagnostic applications. In a nutshell, this article summarizes the advantages and limitations of various biohybrid nano-platforms, their clinical potential and future directions for successful translation in cancer management.

Multi-spectroscopic and thermodynamic profiles on HSA binding of Cassia fistula leaf based potential antibacterial and anticancer silver nanoparticles

Here, a simple, one step, lucrative and green synthesis of Cassia fistula leaf extract inspired antibacterial silver nanoparticles (CF-SNPs) was provided. Characterization of these CF-SNPs were achieved by using various spectroscopic techniques for instance Ultraviolet Visible (UV-Vis) Spectroscopy, Fourier-Transform Infrared (FTIR) Spectroscopy, Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray (EDX). The effective antibacterial action of the CF-SNPs was checked against Escherichia coli (E. Coli) DH5-Alpha where MIC was 1.6 nM. Anticancer dynamism of the CF-SNPs was also tested in opposition to skin melanoma, A375 cell lines in which 4.4 nM was IC50. The binding proneness of HSA towards CF-SNPs was investigated by means of UV-Vis Spectroscopy, Fluorescence Spectroscopy, Time Resolved Fluorescence Spectroscopy, Circular Dichroism (CD) Spectroscopy, Dynamic Light Scattering, and Isothermal Titration Colorimetry (ITC). CD spectroscopy established minor secondary structural exchange of HSA in HSA-CF-SNPs complex. ITC and Time Resolved Fluorescence Spectroscopy verified the static type quenching mechanism involved in HSA-CF-SNPs complex. The binding constant was 3.45 × 108 M-1 at 298.15K from ITC study. The thermodynamic parameters showed that the interaction was occurred spontaneously by the hydrophilic forces and hydrogen bonding.Communicated by Ramaswamy H. Sarma.

A gold nanoparticle-enhanced dCas9-mediated fluorescence resonance energy transfer for nucleic acid detection

Clustered regularly interspaced short palindromic repeats (CRISPR)-associated Cas proteins coupled with pre-amplification have shown great potential in molecular diagnoses. However, the current CRISPR-based methods require additional reporters and time-consuming process. Herein, a gold nanoparticle (AuNP)-enhanced CRISPR/dCas9-mediated fluorescence resonance energy transfer (FRET) termed Au-CFRET platform was proposed for rapid, sensitive, and specific detection of nucleic acid for the first time. In the Au-CFRET sensing platform, AuNP was functionalized with dCas9 and used as nanoprobe. Target DNA was amplified with FAM-labeled primers and then precisely bound with AuNP-dCas9. The formed complex rendered the distance between AuNP acceptor and FAM donor to be short enough for the occurrence of FRET, thus resulting in fluorescence quenching. Moreover, AuNPs were demonstrated to enhance binding efficiency of dCas9 to target DNA in Au-CFRET system. The key factors regarding the FRET efficiency were analyzed and characterized in detail, including the length of donor/acceptor and the size of AuNPs. Under the optimal conditions, Au-CFRET could determinate CaMV35S promoter of genetically modified rice as low as 21 copies μL-1. Moreover, Au-CFRET sensing system coupled with one-step extraction and recombinase polymerase amplification can identify the genuine plant seeds within 30 min from sampling to results at room/body temperature without expensive equipment or technical expertise, and requires no additional exogenous reporters. Therefore, the proposed sensing platform significantly simplified the system and shortened the assay time for nucleic acid diagnoses.

Applications of Au25 Nanoclusters in Photon-Based Cancer Therapies

Atomically precise gold nanoclusters (AuNCs) exhibit unique physical and optical properties, making them highly promising for targeted cancer therapy. Their small size enhances cellular uptake, facilitates rapid distribution to tumor tissues, and minimizes accumulation in non-target organs compared to larger gold nanoparticles. AuNCs, particularly Au25, show significant potential in phototherapy, including photothermal (PTT), photodynamic (PDT), and radiation therapies. These therapies benefit with minimal damage to surrounding healthy tissue. AuNCs also demonstrate excellent stability and biocompatibility, crucial for their effective use in clinical applications. Recent advances in the synthesis and functionalization of AuNCs have further improved their therapeutic efficacy, making them versatile agents for enhancing cancer treatment outcomes. Ongoing research aims to better understand their pharmacokinetics, biodistribution, and long-term safety, paving the way for their broader application in advanced cancer therapies.

Utilizing nanomaterials for cancer treatment and diagnosis: an overview

Cancer is a deadly disease with complex pathophysiological nature and is the leading cause of death worldwide. Traditional diagnosis methods often detect cancer at a considerably critical stage and the conventional methods of treatment like chemotherapy, radiation therapy, targeted therapy, and immunotherapy have several limitations, multidrug resistance, cytotoxicity, and lack of specificity are a few examples. These pose substantial challenge for effective and favourable cancer treatment. The advent of nanotechnology has revolutionized the face of cancer diagnosis and treatment. Nanoparticles, which have a size range of 1-100 nm, are biocompatible and have special optical, magnetic, and electrical capabilities, less toxic, more stable, exhibit permeability and retention effect, and are used for precise targeting. There are several classes of nanoparticles each having their own sets of unique properties. NPs have played an important role in the drug delivery system, overcoming the multi-drug resistance, reducing the side-effects as seen in conventional therapeutic methods and hence able to solve the limitations of conventional methods of diagnosis and treatment. This review discusses the four major classes of nanoparticles (Lipid based NPs, Carbon NPs and Metallic NPs and Polymeric NPs): their discovery and introduction in medical field, unique properties and characteristics, advantages and disadvantages, sub-categories and characteristics of these categories, major area of application in Cancer diagnosis and treatment, and latest methodologies where these are used in cancer treatment.