Search Results (2,087)

Background/Objectives: One of the ongoing clinical constraints is limiting microbial growth on prostheses, justifying the need for material surface enhancements to reduce microbial complications. This study aimed to investigate a potentially applicable and reproducible coating technique to overcome clinical microbial challenges. Methods: Silver (Ag) nanoparticles (NPs) were applied to three types of materials through spray, spin, and dip coating techniques. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy, energy-dispersive X-ray fluorescence (EDXRF), and inductively coupled plasma optical emission spectroscopy (ICP-OES) were performed. Subsequent optimization of spray numbers was determined. Antimicrobial performance of one- and three-layered coatings was evaluated through agar diffusion, direct contact, and adhesion (time-dependent) assays against Pseudomonas aeruginosa (P. aeruginosa). Results: Spray coating exhibited superior coating uniformity. In total, 15 sprays were determined as an effective number for a single-layer coating. EDS confirmed Ag NP presence; FTIR revealed no chemical alteration. Disk diffusion tests showed no inhibition zones. Adhesion and direct contact tests displayed antibacterial activity. The effect was superior in direct contact test. Short-term time-dependent adhesion test of one-layer coating of acrylic and silicone had a consistent decrease in bacterial amount, whilst zirconium had only a strong initial activity. In general, the three-layer coating did not reveal a higher antimicrobial activity, suggesting that the increase in layering can negatively impact surface effectiveness. Conclusions: Spray coating of Ag NPs represents a potentially feasible and relevant strategy for enhancing the antibacterial properties of dental and maxillofacial prosthetic materials without compromising their inherent physicochemical characteristics, pending further cytotoxicity and in vivo validation. Full article

Rapid detection of heavy metals is vital for monitoring surface water contamination and preventing environmental and health risks. Traditional detection methods for metals such as lead and copper often require sophisticated, costly instrumentation, limiting their use in routine analyses. To address this challenge, we developed a cost-effective fluorescence-based approach using semiconductor quantum dots (QDs) as nanosensors for metal ion detection. The QDs were synthesized directly in aqueous medium through a reflux-assisted process employing cadmium precursors, selenium, thioglycolic acid (TGA), and branched polyethyleneimine (PEI, Mw ~25,000) as stabilizing agents. Structural analysis revealed nanoparticles with diameters below 5 nm, spherical morphology, and a zinc blende (face-centered cubic) crystalline structure. Optical characterization by UV–Vis, photoluminescence (PL), and FTIR spectroscopy confirmed effective surface functionalization and strong quantum confinement. PEI-capped QDs exhibited enhanced colloidal stability and showed pronounced fluorescence quenching in the presence of Pb²⁺ ions, indicating high sensitivity and selectivity toward lead. Both TGA- and PEI-capped QDs also demonstrated moderate responses to Co²⁺ but negligible interaction with Sn²⁺, confirming ion-specific detection. Overall, this study demonstrates that surface-engineered QDs constitute a simple, accessible platform for selective detection of toxic metals, with promising applications in environmental monitoring and water quality assessment. Full article

In medicine, nanoparticles are used for various purposes, including theranostics, imaging, diagnostics, drug delivery, tissue regeneration and targeted cancer treatments, and to minimize the harmful side effects associated with conventional therapies. Target-specific biomolecules, such as silica nanoparticles (SiNPs) labeled with metallic radionuclides, are becoming increasingly popular. The choice of radionuclide is based on its nuclear properties. Silica has several advantages for nanoparticle synthesis, including high biocompatibility, the capacity for drug encapsulation due to its porous structure, and the potential for extensive surface functionalization, including radiolabeling for imaging and therapeutic applications. A radionuclide can be attached to a silica nanoparticle either directly or through the use of chelators or polymers. Additionally, the capability to encapsulate therapeutic agents within such systems offers significant potential for the development of targeted therapies. This study aims to provide a comprehensive overview of recent developments in the radiolabeling of silica-based nanoparticles, with a focus on their application in nuclear medicine, particularly in diagnostic imaging and targeted radionuclide therapy. Theranostics employs a range of imaging modalities to guide and monitor therapeutic interventions. Principal techniques include positron emission tomography (PET), single-photon emission computed tomography (SPECT), magnetic resonance imaging (MRI), and Optical Imaging (such as fluorescence and bioluminescence). These imaging methods enable precise visualization of pathological sites, facilitate tracking of therapeutic agent distribution, and permit real-time assessment of treatment efficacy. Full article

Since its introduction in 2006, DNA origami has enabled the fabrication of a wide variety of two- and three-dimensional DNA nanostructures. From the very beginning, researchers have explored these nanostructures as programmable nanobreadboards with hundreds of uniquely addressable positions, allowing precise spatial arrangement of biomolecules, fluorophores, and nanoparticles. This capability has been leveraged to create functional DNA nanomachines capable of single-molecule detection. Here, DNA origami is utilized to precisely engineer various nanoarchitectures, such as conformational switches and plasmonic hotspots. Through coupling of these concepts with tailored readout strategies, true single-molecule detection can be achieved. This literature review systematically examines the development of DNA origami-based single-molecule detection concepts. We first explore general design principles to produce functional DNA nanostructures, followed by an overview of non-fluorescence-based approaches employing atomic force microscopy, nanopores, and optical nanoantennas with surface-enhanced Raman spectroscopy readout, as well as fluorescence-based approaches relying on dynamic DNA nanostructures and optical nanoantennas with fluorescent readout. We highlight key trends as well as the remaining technology gaps that should be bridged to further advance DNA origami towards next-generation single-molecule detection. Full article

In recent decades, plastic consumption has risen across various industries and everyday products, leading to greater plastic use and the generation of waste, which results in the leaching of micro- and nanoplastics into the environment. This review summarizes recent analytical methods for the detection of nanoplastics (NPs) in several marine matrices, divided into three main stages: extraction, separation, and identification. The literature reviewed indicates that chemical and enzymatic digestion are the most commonly used procedures for the extraction step. For the separation step, flotation, filtration, and centrifugation are the most used techniques. Finally, two groups of techniques may be used for the identification step. The first category consists of methods used for qualitative identification, with spectroscopic methods such as Raman and FTIR being the most frequently used. The second category comprises those used for the quantitative analysis of NPs, where fluorescence-based methods and nanoparticle tracking analysis are increasingly used for this assessment. Despite these advances, significant challenges remain, such as matrix interferences caused by salinity and organic matter, low environmental concentrations of NPs, and the lack of standardized protocols. This review highlights the need for standardized protocols, validated reference materials, and integrated multi-technique approaches to improve the comparability of nanoplastics measurements in marine environments. Full article

Alternating glycopolymers bearing periodically arranged pendant carbohydrate residues were synthesized by reversible addition–fragmentation chain transfer (RAFT) copolymerization of maltose-containing vinyl ether (MalVE) and ethyl maleimide (EtMI). The resulting trithiocarbonate-terminated polymers were subsequently converted into thiol-terminated glycopolymers through post-polymerization end-group transformation. These structurally well-defined alternating glycopolymers were immobilized onto gold nanoparticles (AuNPs) via Au–S interactions to construct glycopolymer-functionalized glycointerfaces. Surface functionalization of the AuNPs was confirmed by an increase in hydrodynamic diameter from approximately 42 to 59 nm after polymer immobilization. The resulting glycopolymer-functionalized AuNPs exhibited concentration-dependent lectin-mediated aggregation behavior in the presence of concanavalin A, accompanied by characteristic red shifts and broadening of the localized surface plasmon resonance (LSPR) band arising from multivalent carbohydrate–lectin interactions at the nanoparticle interface. Although the apparent association constants obtained for free alternating glycopolymers using fluorescently labeled lectin cannot be directly compared with those obtained from LSPR-based aggregation assays of AuNP-immobilized glycopolymers, the values increased from the order of 10⁵ L mol⁻¹ in solution to the order of 10⁷ L mol⁻¹ at the nanoparticle interface. This trend suggests that immobilization onto AuNPs enhances multivalent carbohydrate–lectin interactions through multivalent presentation of the glycopolymer chains at the nanoparticle interface. As a control experiment, peanut agglutinin (PNA), which does not recognize maltose residues, was added to the glycopolymer-functionalized AuNPs. No significant LSPR shift or spectral broadening was observed, indicating that nanoparticle aggregation was not induced by nonspecific lectin addition but arose from specific interactions between maltose residues and Con A. Quantitative analysis suggested that polymer chain length may influence the aggregation behavior. These results demonstrate that alternating glycopolymers provide a useful platform for constructing sequence-regulated glycointerfaces and for investigating multivalent biomolecular interactions at nanoparticle surfaces. Full article

Analysis of protein binding affinity to nanoparticles is essential for understanding how nanoparticles behave in biological systems and for optimizing their applications in medicine and biotechnology. This study demonstrates the dependence of protein binding and fluorescence quenching constants (HEWL and BSA) in the presence of gold (AuNP) or iron oxide (IONP) nanoparticles on pH and temperature. The highest binding and quenching constants were observed for proteins with gold nanoparticles (~10⁹ M⁻¹). No clear effect of pH or temperature on either the binding or quenching constants of proteins with gold nanoparticles was detected. Conversely, different temperature trends were observed for the binding and quenching constants at different pH levels and for different proteins with iron oxide nanoparticles. It was shown that the nature of the nanoparticles has the strongest influence on their interactions with proteins, while the influence of environmental conditions can be considered secondary. Full article

Nanotheranostics integrate theranostic functions onto a single nanoscale platform, and have become a new approach in precision medicine. Nanotheranostics rely on probes. However, traditional fluorescent probes often exhibit aggregation-caused quenching (ACQ) when loaded at high concentrations onto nanocarriers, severely limiting their imaging performance. Aggregation-induced emission agents (AIEgens) offer a solution to this long-standing problem through their ability to enhance fluorescence during aggregation. This mini-review systematically outlines nanotheranostic systems based on aggregation-induced emission (AIE). We first introduce the basic mechanism of AIE (the limitation of molecular internal motion) and its advantages over traditional fluorescent probes. Then, we discuss the design strategies of AIE nanoprobes according to the types of nanocarriers (including liposomes, polymer nanoparticles, and self-assembling systems). Additionally, we emphasize the disease-specific AIE nanotheranostic designs tailored for pathological microenvironments such as tumors, neurodegenerative diseases, and inflammatory diseases. Finally, we conduct an in-depth analysis of the current challenges hindering clinical translation, and propose future AIE nanotheranostic technologies applicable to clinical practice and the direction for personalized medicine. Full article

Water contaminated by textile dyes is a tremendous risk to human health and the environment due to its toxic and carcinogenic nature, thus requiring advanced and efficient removal strategies. Therefore, this study aimed to investigate the photo-oxidation performance of few- and multi-layer Ti₃C₂T_x nanosheets (MXenes) decorated with TiO₂ nanoparticles for methyl orange removal from synthetic solutions. The quantification of photogenerated hydroxyl radicals by fluorescence revealed much higher OH^• production for TiO₂-decorated samples, especially for multi-layer MXene, in which it was 2.8 times higher than that of few-layer MXene. However, photocatalysis was morphology-controlled: despite lower OH^•, the few-layer MXene achieved the highest dye conversion (~45% after 5 h), attributed to shorter charge migration distances and more accessible TiO₂ active sites, enabling effective h⁺ and superoxide-driven pathways. Moreover, the detected -OH surface terminations verified on MXenes promoted a notable adsorption capacity, especially for the multi-layer samples (~31%) via interlayer trapping and H-bonding. Therefore, our results demonstrate that few-layer MXenes are promising candidates for the efficient removal of methyl orange and highlight the potential of TiO₂-decorated MXenes as promising photocatalysts for environmental remediation. Full article

An optical sensor based on a polymethacrylate matrix (PMM) with immobilized gold nanoparticles (Au⁰ NPs) has been developed for the determination of pollutants in environmental samples. The nanoparticles are synthesized by chemical reduction of Au(III) to Au⁰ using sodium borohydride, which yields conglomerates of spherical particles with an absorption maximum at 530 nm. The time stability of the nanocomposite is demonstrated, as well as the ability to control the nanoparticle loading in the matrix by varying the concentration of the HAuCl₄ solution. The analytical capability of the PMM–Au⁰ system is demonstrated for the direct determination of tetracycline in river water in two linear concentration ranges: 0.001–0.010 mg/L and 0.025–0.100 mg/L, with detection limits of 0.0005 mg/L and 0.012 mg/L, respectively. The determination of tetracycline is based on the enhancement of its intrinsic fluorescence at 520 nm by gold nanoparticles in the solid phase following solid-phase extraction from water in the anionic form H₂TC⁻ using PMM–Au⁰. The colorimetric determination of thiocyanate anions is based on a color change of the PMM–Au⁰ nanocomposite from red to blue, corresponding to a shift in the plasmon absorption maximum from 530 nm to 630 nm. The sensor exhibits a linear response in the thiocyanate concentration range of 0.3–50.0 mg/L, with a detection limit of 0.1 mg/L. Thus, the multifunctional PMM–Au⁰ sensor has been used for the determination of various analytes employing different modes of analytical signal readout after minimal sample preparation. Full article

This study reports the green synthesis of silver nanoparticles (AgNPs) using Salvia tomentosa L. leaf extract, and evaluates their physicochemical characteristics and biointerfacial performance, including DNA interaction, antibacterial activity, and antioxidant capacity. AgNP formation was confirmed by UV-Vis spectroscopy through a surface plasmon resonance band at 472 nm. SEM imaging showed predominantly spherical particles with sizes of 30–80 nm and a zeta potential of −17.3 mV, and EDX verified the elemental presence of silver. FTIR spectra indicated that plant-derived biomolecules, particularly phenolics, contributed to the reduction and capping/stabilization of AgNPs. XRD analysis confirmed a crystalline face-centered cubic structure. The AgNPs exhibited moderate, spontaneous binding to DNA (Kb ≈ 1.07 × 10⁴ M⁻¹), characterized by pronounced hyperchromism without evidence of intercalation. Competitive fluorescence assays supported a predominantly non-intercalative, surface-associated interaction with minor groove perturbation, while agarose gel electrophoresis indicated preserved plasmid integrity and no extensive strand cleavage. Collectively, these results suggest reversible and structurally non-destructive AgNP–DNA complexation, indicating their potential for nucleic acid-related nano-biointerface studies, while further investigations are required to evaluate their suitability for biomedical applications. The biosynthesized AgNPs showed enhanced antibacterial activity against Gram-positive (Bacillus cereus) and Gram-negative (Pantoea agglomerans) bacteria compared with the leaf extract, whereas AgNO₃ produced the strongest immediate effect, consistent with rapid Ag⁺ release. Antioxidant activity assessed by DPPH and ABTS assays showed strong radical-scavenging activity for the extract, in line with its high total phenolic content (206.2 mg GAE/g). Although AgNPs displayed lower phenolic content (164.2 mg GAE/g) and reduced antioxidant activity than the extract, they retained moderate scavenging capacity, indicating effective surface functionalization by phytochemicals. Overall, S. tomentosa leaf extract-capped AgNPs combine defined physicochemical features with non-destructive DNA association and antibacterial efficacy, underscoring their promise as phytochemical-functionalized nano-biointerfaces for antimicrobial and related biointerface applications. Full article

A method for synthesizing theranostic nanoparticles (NPs) based on a silica core, a mercapto spacer, a cardioprotector, and a fluorescent dye has been developed. The total amount of grafted mercapto groups was 0.079 mmol/g. The amount of accessible mercapto groups on the surface of the synthesized particles, calculated using the Kunkel, Buckley, and Gorin method, was 0.025 mmol/g. A total of 0.031 mmol/g of adenosine and 0.0087 mmol/g of indocyanine green are grafted onto the mercapto spacer. Both substances are presumably attached via hydrogen bonding to the modified silica nanoparticle in a ratio of 60/40% for adenosine and indocyanine green, respectively. The resulting nanoparticles exhibit no hemolytic activity. Intensive adenosine release occurs within 90 min and continues for up to 24 h. Based on biodistribution, significant accumulation of the nanoparticles occurs in the liver. Full article

Hierarchical functionalisation of the UiO-66(Zr)-NH₂ metal–organic framework with cysteine, poly(ethylene glycol) (PEG), and the SARS-CoV-2 spike receptor-binding domain (RBD) was developed to enable receptor-specific interaction with the angiotensin-converting enzyme 2 receptor (ACE2) in model cells. Post-synthetic modification using cysteine and heterobifunctional PEG linkers allowed controlled bioconjugation of SpyTag-labelled RBD via SpyTag/SpyCatcher chemistry, while preserving the crystallinity, microporosity, and intrinsic optical properties of the UiO-66(Zr)-NH₂ framework. Comprehensive physicochemical characterisation confirmed successful surface functionalisation, tunable aggregation behaviour, and retention of multimodal optical characteristics. Cellular studies in HEK293T and HeLa cells overexpressing EGFP-tagged ACE2 demonstrated enhanced and selective association and uptake of RBD-functionalised nanoparticles compared with non-targeted analogues. Multimodal fluorescence imaging, fluorescence lifetime imaging microscopy, flow-cytometry, and electron microscopy indicated ACE2-dependent endocytic internalisation, with predominant localisation in endosomal and autophagosomal compartments, while both amine- and cysteine-modified formulations exhibited good biocompatibility. Overall, this study establishes a virus-mimetic, ACE2-targeted UiO-66(Zr)-based nanosystem as a proof-of-concept biointerface platform for receptor-specific cellular delivery and imaging, providing a foundation for future MOF-based nanocarriers exploiting ligand–receptor interactions. Full article

Optical chromatography (OC) has emerged as a powerful, label-free technique for the precise manipulation and separation of micro- and nanoparticles based on their intrinsic biophysical properties, including size, refractive index, and morphology. By balancing optical radiation pressure with fluid drag forces, OC enables high-resolution sorting of diverse analytes—from synthetic colloids to biological cells and pathogens—without the need for fluorescent labels or chemical modifications. Recent advancements in integrated optofluidic platforms, such as plasmonic microlens arrays, fiber-based systems, and hybrid optical–electrical detection approaches, have significantly enhanced OC capabilities, addressing long-standing challenges in scalability, throughput, and sensitivity, and facilitated its transition toward compact, application-oriented analytical platforms. These innovations have expanded OC applications in critical biomedical fields, including exosome isolation, pathogen detection, and viral infection monitoring. Furthermore, the integration of OC with tunable resistive pulse sensing (TRPS) presents a promising avenue for simultaneous particle fractionation and characterization, overcoming key limitations of conventional resistive pulse techniques. In this review, we provide a comprehensive overview of the fundamental principles of OC, followed by recent progress in particle separation strategies and integrated optofluidic system design. We further highlight emerging applications in bioanalysis and discuss future directions toward high-throughput, multimodal, and clinically relevant OC platforms. Full article

Regulatory T cells (Tregs) play a key role in immune tolerance and are promising targets for treating immune-mediated diseases. This study investigated the direct effects of PEGylated graphene oxide nanoparticles (LP-GO, BP-GO at 5–25 μg/mL) and fullerenol C₆₀(OH)₂₄ (25–200 μg/mL) on human Treg viability and differentiation in vitro. Tregs were induced from peripheral blood CD4⁺ T cells using IL-2, TGF-β, and CD2/CD3/CD28 activation beads for 72 h with nanoparticles. Assessments included viability, apoptosis (Zombie aqua/Annexin V), phenotype (CD45⁺CD4⁺CD25⁺CD127^dim/−FOXP3⁺), nanoparticle sorption (intrinsic fluorescence), and IL-10 production. Neither PEGylated graphene oxide nor fullerenol C₆₀(OH)₂₄ affected T-helper (CD4⁺) viability (95.35–96.15%) nor early/late apoptosis levels. Despite this, we found a decrease in the percentage of CD4⁺ cells in cultures exposed to 50–200 μg/mL of fullerenol C₆₀(OH)₂₄. The percentage and absolute number of Treg cells decreased with 100–200 μg/mL of fullerenol, while IL-10 levels declined following treatment with 200 μg/mL of the same nanoparticles. Graphene oxide nanoparticles showed virtually no localization within or on cells. However, T helper and Treg cells demonstrated concentration-dependent sorption of fullerenol C₆₀(OH)₂₄ at concentrations of 100–200 μg/mL without a reduction in viability. These findings demonstrate good in vitro biocompatibility of the nanoparticles at pharmacological concentrations up to 25 μg/mL, alongside the inhibition of Treg differentiation with 100–200 μg/mL of fullerenol C₆₀(OH)₂₄. Full article