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The article discusses the development and clinical application of colloidal nanoparticles (NPs) in disease treatment and diagnosis, with current focus on the challenges related to biodistribution and pharmacokinetics. Topics include the physicochemical properties of NPs affecting their interactions with cells, the multiple pathways of NP uptake and excretion in the body, and the importance of crossing biological barriers for effective drug delivery.

Analytical nanoscience and nanotechnology (AN&N) is a clear trend in current analytical chemistry in which Prof. Valcárcel was working during his last research period. Prof. Valcárcel contributed decisively to the modernization of analytical chemistry, both in the claim of its foundations and basic principles and in its important applied facet and its role to problem solving. Graph With all this activity and these important milestones, Prof. Valcárcel lived with intensity and hyperactivity and with passion and enthusiasm that he transmitted to everyone around him. [Extracted from the article]

Human ENP exposure is inevitable and the novel, size-dependent physicochemical properties that enable ENPs to be beneficial in innovative technologies are concomitantly causing heightened public concerns as to their potential adverse effects upon human health. This study aims to deduce the mechanisms associated with potential ENP mediated (geno)toxicity and impact upon telomere integrity, if any, of varying concentrations of both ∼16 nm (4.34 × 10−3 to 17.36 × 10−3 mg/mL) Gold (Au) and ∼14 nm (0.85 × 10−5 to 3.32 × 10−5 mg/mL) Silver (Ag) ENPs upon two commonly used lung epithelial cell lines, 16HBE14o− and A549. Following cytotoxicity analysis (via Trypan Blue and Lactate Dehydrogenase assay), two sub-lethal concentrations were selected for genotoxicity analysis using the cytokinesis-blocked micronucleus assay. Whilst both ENP types induced significant oxidative stress, Ag ENPs (1.66 × 10−5 mg/mL) did not display a significant genotoxic response in either epithelial cell lines, but Au ENPs (8.68 × 10−3 mg/mL) showed a highly significant 2.63-fold and 2.4-fold increase in micronucleus frequency in A549 and 16HBE14o− cells respectively. It is hypothesized that the DNA damage induced by acute 24-h Au ENP exposure resulted in a cell cycle stall indicated by the increased mononuclear cell fraction (>6.0-fold) and cytostasis level. Albeit insignificant, a small reduction in telomere length was observed following acute exposure to both ENPs which could indicate the potential for ENP mediated telomere attrition. Finally, from the data shown, both in vitro lung cell cultures (16HBE14o− and A549) are equally as suitable and reliable for the in vitro ENP hazard identification approach adopted in this study. [ABSTRACT FROM AUTHOR]

Hypothesis An effective surface passivation is crucial to obtain quantum dots (QDs) with good photoluminescence response. Whereas the encapsulation of QDs inside amphiphilic polymers provides colloidal stability, a decrease in the quantum yield (QY) is observed. Pyridyl motifs are known to bind strongly to the ZnS on core/shell QD and increase the structure rigidity. Hence, the incorporation of pyridyl groups into the polymer could make it more compact in order to improve the optical behavior of the QDs. Experiments Pyridyl-modified amphiphilic polymeric ligands were synthesized based on a poly(isobutylene- alt -maleic anhydride) backbone with pyridyl and alkyl end-groups as anchoring groups. The proportion of both ligands was optimized. The resulting QDs were characterized using complementary techniques such as absorption spectroscopy, static and time-resolved photoluminescence spectroscopy, transmission electron microscopy, and dynamic light scattering. Findings Coating with the designed polymer maintains the high QY of the QDs after being transferred to water and provides them colloidal stability under relevant biological conditions ( i.e. wide range of pH and ionic strength, biological buffers and stability over time). The significant improvements of such ligand may be attributed to the synergistic effect of two anchoring groups (pyridyl and alkyl groups) which establish different types of interaction with the QD. [ABSTRACT FROM AUTHOR]

The article focuses on a study related to cellular stability of inorganic nanoparticles and effects of particle functionality, cytotoxicity, and biomedical applications. Topics discussed include role of nanoparticles in nanotechnology, commercial and medical use of nanoparticles, and use of iron oxide nanoparticles in both life science related applications and clinical research.

Examines the association of semiconductor nanocrystals with oligonucleotides. Properties of nanocrystals and DNA; Detection of carboxyl groups on the nanocrystals; Functions of DNA-nanocrystal conjugates.

Abstract An essential requirement for successful long-term coupling between neuronal assemblies and semiconductor devices is that the neurones must be able to fully develop their electrogenic repertoire when growing on semiconductor (silicon) substrates. While it has for some time been known that neurones may be cultured on silicon wafers insulated with SiO[sub 2] and Si[sub 3]N[sub 4], an electrophysiological characterisation of their development under such conditions is lacking. The development of voltage-dependent membrane currents, especially of the rapid sodium inward current underlying the action potential, is of particular importance because the conductance change during the action potential determines the quality of cell-semiconductor coupling. We have cultured rat striatal neurones on either glass coverslips or silicon wafers insulated with SiO[sub 2] and Si[sub 3]N[sub 4] using both serum-containing and serum-free media. We here report evidence that not only serum-free culture media but also growth on semiconductor surfaces may negatively affect the development of voltage-dependent currents in neurones. Furthermore, using surface-charge measurements with the atomic force microscope, we demonstrate a reduced negativity of the semiconductor surface compared to glass. The reduced surface charge may affect cellular development through an effect on the binding and/or orientation of extracellular matrix proteins, such as laminin. Our findings therefore suggest that semiconductor substrates are not entirely equivalent to glass in terms of their effects on neuronal cell growth and differentiation. [ABSTRACT FROM AUTHOR]

Presents information on a study which investigated the ability of the light-addressable potentiometric sensor (LAPS) to record extracellular potentials of cardiac cells. Cell culture; Photocurrent characteristics of LAPS; Materials and methods; Results and discussion; Conclusions.

Encapsulation with polymers is a well-known strategy to stabilize and functionalize nanomaterials and tune their physicochemical properties. Amphiphilic copolymers are promising in this context, but their structural diversity and complexity also make understanding and predicting their behavior challenging. This is particularly the case in complex media which are relevant for intended applications in medicine and nanobiotechnology. Here, we studied the encapsulation of gold nanoparticles and quantum dots with amphiphilic copolymers differing in their charge and molecular structure. Protein adsorption to the nanoconjugates was studied with fluorescence correlation spectroscopy, and their surface activity was studied with dynamic interfacial tensiometry. Encapsulation of the nanoparticles without affecting their characteristic properties was possible with all tested polymers and provided good stabilization. However, the interaction with proteins and cells significantly depended on structural details. We identified statistical copolymers providing strongly reduced protein adsorption and low unspecific cellular uptake. Interestingly, different zwitterionic amphiphilic copolymers showed substantial differences in their resulting bio-repulsive properties. Among the polymers tested herein, statistical copolymers with sulfobetaine and phosphatidylcholine sidechains performed better than copolymers with carboxylic acid- and dimethylamino-terminated sidechains. [ABSTRACT FROM AUTHOR]

Among various hybrid nanomaterials, the combination of plasmonic nanoparticles and fluorophores in a single multifunctional nanoplatform, so‐called plasmophores, has attracted significant attention in different fields such as dark field, fluorescence, and photoacoustic imaging, biosensing, photothermal, and photodynamic therapy. Herein, author report a facile and controlled synthesis route of hybrid nanoplatforms composed of fluorescent gold nanoclusters (GNCs) coupled to plasmonic gold nanorods (GNRs) using controlled silica (SiO2) dielectric spacers of different thicknesses from now on referred to as GNR@SiO2@GNC plasmophores. The results show different degrees of plasmon‐enhanced fluorescence of the GNCs in their plasmophore hybrid system when placed at different distances from the plasmonic cores of the GNRs. On the other hand, these plasmophores show enhanced thermal stability compared to GNRs@CTAB (CTAB, cetyl trimethyl ammonium bromide). This results also demonstrated that upon annealing at elevated temperatures (800–1000 °C), the GNRs in the plasmophores are more thermally stable and robust than the GNRs@CTAB. More surprisingly, despite the commonly reported very low melting temperature of smaller‐size nanocrystals, the GNCs in the plasmophores showed high thermal stability and do not exhibit significant structural changes at elevated temperatures (800–1000 °C). [ABSTRACT FROM AUTHOR]

Abstract The atomic force microscope (AFM) was used to analyse the contractile behaviour of embryonic chicken cardiomyocytes. The mechanical pulsing of cardiomyocyres was analysed by observing active single cells as well as cells in a confluent layer. When embedded in a confluent layer, owing to synchronisation, pulsing of the cells was often found to be very stable in terms of frequency and amplitude of the beat, including negative as well as positive amplitudes. Nevertheless, owing to movements of contraction centres within the layer, a flipping of the sign of the amplitude did sometimes also occur on a time scale of minutes. In contrast, single cells often changed between active periods of pulsing and periods of complete quietness. Also characteristic parameters like beat period and pulse amplitude were observed to be unstable. Finally, we combined the abilities of the AFM to image adherent single cells and to record locally beat amplitudes, to characterise the pulsing behaviour of single cells laterally resolved. [ABSTRACT FROM AUTHOR]

A spherically folded capacitive pressure sensor array is introduced and characterized. By placing the sensor array between the ball and the cavity of artificial joints, the pressure distribution within the joint was recorded with spatial resolution for different size matching between the ball and the cavity, for different directions of loading and for joints with incomplete cavities. The performance of the sensor array is analyzed, possible fields of application as well as its limitations are discussed. [Copyright &y& Elsevier]

X-ray fluorescence imaging (XRF-imaging) with subcellular resolution is used to study the intracellular integrity of a protein corona that was pre-formed around gold nanoparticles (AuNP). Artificial proteins engineered to obtain Gd coordination for detection by XRF-imaging were used to form the corona. Indications about the degradation of this protein corona at a cellular and subcellular level can be observed by following the Au and Gd quantities in a time and spatial-dependent manner. The extended acquisition times necessary for capturing individual XRF-imaging cell images result in relatively small sample populations, stressing the need for faster image acquisition strategies in future XRF-imaging-based studies to deal with the inherent variability between cells. Still, results obtained reveal degradation of the protein corona during cellular trafficking, followed by differential cellular processing for AuNP and Gd-labelled proteins. Overall, this demonstrates that the dynamic degradation of the protein corona can be tracked by XRF-imaging to a certain degree. [ABSTRACT FROM AUTHOR]

Self‐assembly of nanoparticles (NPs) has evolved into a powerful tool for the synthesis of superstructures with tailored properties. The quality, diversity, and complexity of synthesized structures are continuously improving and fascinating new collective properties are demonstrated. At the same time, the rapid development of electron microscopy and synchrotron sources for X‐rays has enabled new exciting experimental approaches to study structure and structure formation in the context of NP self‐assembly. In this review, some recent studies and what can be learned from them are highlighted and discussed. It is started with a general introduction covering important concepts, experimental approaches, commonly obtained structures, the ideas of artificial atoms, and emerging properties are discussed. Recent experimental in situ and ex situ approaches with state‐of‐the‐art electron microscopy and X‐ray diffraction and scattering that helped to obtain a detailed picture of NP self‐assembly processes and resulting structures are then presented. [ABSTRACT FROM AUTHOR]

CuBi2O4 has recently emerged as a promising photocathode for photo‐electrochemical (PEC) water splitting. However, its fast degradation under operation currently poses a limit to its application. Here, we report a novel method to study operando the semiconductor‐electrolyte interface during PEC operation by surface‐sensitive high‐energy X‐ray scattering. We find that a fast decrease in the generated photocurrents correlates directly with the formation of a metallic Bi phase. We further show that the slower formation of metallic Cu, as well as the dissolution of the electrode in contact with the electrolyte, further affect the CuBi2O4 activity and morphology. Our study provides a comprehensive picture of the degradation mechanisms affecting CuBi2O4 electrodes under operation and poses the methodological basis to investigate the photocorrosion processes affecting a wide range of PEC materials. [ABSTRACT FROM AUTHOR]

CuBi2O4 has recently emerged as a promising photocathode for photo‐electrochemical (PEC) water splitting. However, its fast degradation under operation currently poses a limit to its application. Here, we report a novel method to study operando the semiconductor‐electrolyte interface during PEC operation by surface‐sensitive high‐energy X‐ray scattering. We find that a fast decrease in the generated photocurrents correlates directly with the formation of a metallic Bi phase. We further show that the slower formation of metallic Cu, as well as the dissolution of the electrode in contact with the electrolyte, further affect the CuBi2O4 activity and morphology. Our study provides a comprehensive picture of the degradation mechanisms affecting CuBi2O4 electrodes under operation and poses the methodological basis to investigate the photocorrosion processes affecting a wide range of PEC materials. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "DNA-controlled dynamic colloidal nanoparticle systems for mediating cellular interaction" by Seiichi Ohta and colleagues that was published in the previous issue.

The infiltration of immune cells into sites of inflammation is one key feature of immune mediated inflammatory diseases. A detailed assessment of the in vivo dynamics of relevant cell subtypes could booster the understanding of this disease and the development of novel therapies. We show in detail how advanced X-ray fluorescence imaging enables such quantitative in vivo cell tracking, offering solutions that could pave the way beyond what other imaging modalities provide today. The key for this achievement is a detailed study of the spectral background contribution from multiple Compton scattering in a mouse-scaled object when this is scanned with a monochromatic pencil X-ray beam from a synchrotron. Under optimal conditions, the detection sensitivity is sufficient for detecting local accumulations of the labelled immune cells, hence providing experimental demonstration of in vivo immune cell tracking in mice. [ABSTRACT FROM AUTHOR]

In recent years, much effort has been invested into developing multifunctional drug delivery systems to overcome the drawbacks of conventional carriers. Magnetic nanoparticles are not generally used as carriers but can be functionalised with several different biomolecules and their size can be tailored to present a hyperthermia response, allowing for the design of multifunctional systems which can be active in therapies. In this work, we have designed a drug carrier nanosystem based on Fe3O4 nanoparticles with large heating power and 4-amino-2-pentylselenoquinazoline as an attached drug that exhibits oxidative properties and high selectivity against a variety of cancer malignant cells. For this propose, two samples composed of homogeneous Fe3O4 nanoparticles (NPs) with different sizes, shapes, and magnetic properties have been synthesised and characterised. The surface modification of the prepared Fe3O4 nanoparticles has been developed using copolymers composed of poly(ethylene-alt-maleic anhydride), dodecylamine, polyethylene glycol and the drug 4-amino-2-pentylselenoquinazoline. The obtained nanosystems were properly characterised. Their in vitro efficacy in colon cancer cells and as magnetic hyperthermia inductors was analysed, thereby leaving the door open for their potential application as multimodal agents. [ABSTRACT FROM AUTHOR]

Self‐assembling monolayers (SAMs) of dithiols play an important role as bivalent linker layer in applications such as photoelectrochemical sensors. However, their formation processes and film structure are not fully understood yet. Herein, a SAM of aromatic trans‐stilbenedithiol (StDT) on Au(111) surfaces is investigated. Using complementary characterization techniques the dependence of the film quality on preparation parameters, such as used solvent, temperature and ambient conditions during and subsequent to preparation is investigated. Furthermore, a remarkably high thermal stability is found which is ascribed to disulfide bridging between the endgroups of the individual molecules. [ABSTRACT FROM AUTHOR]

The article discusses a report in the same issue by González and colleagues regarding the nanoscale construction of complex three-dimensional objects through colloidal chemistry. Researchers synthesized colloidal nanoparticles while controlling for factors such as size, shape, and composition, and employed galvanic deposition and the Kirkendall effect to create cavities within nanoparticles to allow the incorporation of additional materials. The methodologies used by González and colleagues suggest the possibility that complex colloidal nanoparticles can be designed and synthesized for specific uses.

Titanium dioxide nanoparticles (TiO2 NPs) are one of the main sources of the nanoparticulate matter exposure to humans. Although several studies have demonstrated their potential toxic effects, the real nature of the correlation between NP properties and their interaction with biological targets is still far from being fully elucidated. Here, engineered TiO2 NPs with various geometries (bipyramids, plates, and rods) have been prepared, characterized and intravenously administered in healthy mice. Parameters such as biodistribution, accumulation, and toxicity have been assessed in the lungs and liver. Our data show that the organ accumulation of TiO2 NPs, measured by ICP-MS, is quite low, and this is only partially and transiently affected by the NP geometries. The long-lasting permanence is exclusively restricted to the lungs. Here, bipyramids and plates show a higher accumulation, and interestingly, rod-shaped NPs are the most toxic, leading to histopathological pulmonary alterations. In addition, they are also able to induce a transient increase in serum markers related to hepatocellular injury. These results indicate that rods, more than bipyramidal and spherical geometries, lead to a stronger and more severe biological effect. Overall, small physico-chemical differences can dramatically modify both accumulation and safety. [ABSTRACT FROM AUTHOR]

Due to its enormous relevance the corona formation of adsorbed proteins around nanoparticles is widely investigated. A comparison of different experimental techniques is given. Direct measurements of proteins, such as typically performed with mass spectrometry, will be compared with indirect analysis, in which instead information about the protein corona is gathered from changes in the properties of the nanoparticles. The type of measurement determines also whether before analysis purification from unbound excess proteins is necessary, which may change the equilibrium, or if measurements can be performed in situ without required purification. Pros and contras of the different methods will be discussed. [ABSTRACT FROM AUTHOR]

Analyte-sensitive fluorophores are a common tool in analytical chemistry. In case they are conjugated to the surface of colloidal nanoparticles new or improved applications are possible. An overview of the potential of such fluorophore-particle conjugates is given by means of several examples. First, using pH-sensitive fluorophores attached to particles are a helpful tool for investigating particle uptake by cells, as they can indicate whether particles are in the neutral slightly alkaline extracellular medium, or in acidic intracellular vesicles after endocytosis. Second, relating to lifetime-based methodologies, the fluorescence resonance energy transfer between fluorophores attached to quantum dots leads to longer lifetimes, improving their performance and expanding the possibilities of methods, such as lifetime imaging for in vivo applications. It also can be exploited for multiplexing approaches, in which the effective lifetime of the fluorophores can be tuned, allowing thus for the detection of several analytes based on temporal discrimination. Attention is focused to these three areas of application, because they are among the most reported in recent literature, and therefore of particular interest. [ABSTRACT FROM AUTHOR]

Herein we report the synthesis and structural analysis of tunable 1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetic acid (DOTA)‐derivatives bearing azidoethyl side chains. According to the number of azidoethyl side chains, the compounds are termed DOTXAZA (with X=1–4). All derivatives retain the well‐approved DOTA scaffold for metal complexation with 8 coordinating functionalities and are applicable to Cu‐catalyzed alkyne‐azide cycloaddition (CuAAC). They may thus be used to assemble new Gd‐based contrast agents (GBCAs) with tailored pharmacokinetic or MRI properties retaining the high stability of clinically used DOTA‐derived GBCAs. The complex geometry of all DOTXAZA derivatives was investigated in solution with NMR‐spectroscopy of the corresponding Eu‐complexes. A correlation of complex geometry with the longitudinal relaxivity of corresponding Gd‐complexes revealed an increase in relaxivity with increasing substitution number in the DOTXAZA series. Moreover, CuAAC‐modified DOTAZA‐derivatives with neutral, charged, and zwitterionic groups were prepared. Although of similar molecular mass, the corresponding Gd‐complexes revealed pronounced differences in relaxivities from r1=3.9–7.9 mm−1 s−1 in water at 1.5 T and 37 °C. Relaxivities of these complexes were found to be strongly dependent on side chain charge and are most likely determined by second‐sphere water effects. [ABSTRACT FROM AUTHOR]

The growing availability of biomarker panels for molecular diagnostics is leading to an increasing need for fast and sensitive biosensing technologies that are applicable to point-of-care testing. In that regard, homogeneous measurement principles are especially relevant as they usually do not require extensive sample preparation procedures, thus reducing the total analysis time and maximizing ease-of-use. In this review, we focus on homogeneous biosensors for the in vitro detection of biomarkers. Within this broad range of biosensors, we concentrate on methods that apply magnetic particle labels. The advantage of such methods lies in the added possibility to manipulate the particle labels by applied magnetic fields, which can be exploited, for example, to decrease incubation times or to enhance the signal-to-noise-ratio of the measurement signal by applying frequency-selective detection. In our review, we discriminate the corresponding methods based on the nature of the acquired measurement signal, which can either be based on magnetic or optical detection. The underlying measurement principles of the different techniques are discussed, and biosensing examples for all techniques are reported, thereby demonstrating the broad applicability of homogeneous in vitro biosensing based on magnetic particle label actuation. [ABSTRACT FROM AUTHOR]

Food-grade titanium dioxide (E171) contains variable percentages of titanium dioxide (TiO2) nanoparticles (NPs), posing concerns for its potential effects on human and animal health. Despite many studies, the actual relationship between the physicochemical properties of E171 NPs and their interaction with biological targets is still far from clear. We evaluated the impact of acute E171 administration on invertebrate and vertebrate animals. In the nematode, Caenorhabditis elegans, the administration of up to 1.0 mg/mL of E171 did not affect the worm's viability and lifespan, but significantly impaired its pharyngeal function, reproduction, and development. We also investigated whether the intravenous administration of E171 in mice (at the dose of 6 mg/kg/body weight) could result in an acute over-absorption of filter organs. A significant increase of hepatic titanium concentration and the formation of microgranulomas were observed. Interstitial inflammation and parenchymal modification were found in the lungs, coupled with titanium accumulation. This was probably due to the propensity of TiO2 NPs to agglomerate, as demonstrated by transmission electron microscopy experiments showing that the incubation of E171 with serum promoted the formation of compact clusters. Overall, these data emphasize the actual risk for human and animal exposure to E171. [ABSTRACT FROM AUTHOR]

The widespread and increasing use of engineered nanomaterials (ENM) increases the risk of human exposure, generating concern that ENM may provoke adverse health effects. In this respect, their physicochemical characteristics are critical. The immune system may respond to ENM through inflammatory reactions. The NLRP3 inflammasome responds to a wide range of ENM, and its activation is associated with various inflammatory diseases. Recently, anisotropic ENM have become of increasing interest, but knowledge of their effects on the immune system is still limited. The objective of the study was to compare the effects of gold ENM of different shapes on NLRP3 inflammasome activation and related signalling pathways. Differentiated THP-1 cells (wildtype, ASC- or NLRP3-deficient), were exposed to PEGylated gold nanorods, nanostars, and nanospheres, and, thus, also different surface chemistries, to assess NLRP3 inflammasome activation. Next, the exposed cells were subjected to gene expression analysis. Nanorods, but not nanostars or nanospheres, showed NLRP3 inflammasome activation. ASC- or NLRP3-deficient cells did not show this effect. Gene Set Enrichment Analysis revealed that gold nanorod-induced NLRP3 inflammasome activation was accompanied by downregulated sterol/cholesterol biosynthesis, oxidative phosphorylation, and purinergic receptor signalling. At the level of individual genes, downregulation of Paraoxonase-2, a protein that controls oxidative stress, was most notable. In conclusion, the shape and surface chemistry of gold nanoparticles determine NLRP3 inflammasome activation. Future studies should include particle uptake and intracellular localization. [ABSTRACT FROM AUTHOR]

Gold nanostars are among the most efficient plasmonic nanomaterials for optical sensing with surface enhanced Raman scattering. In recent years, gold nanostars have increased relevance in physics, analytical chemistry, environmental science, biology and medicine, and in particular in sensing and therapy. These colloids can sustain ultrastrong electromagnetic fields which allow their use as single particles optical enhancers; are colloidally stable and may have a marked catalytical activity. Due to their exotic shape, these colloids present characteristic optical and reactive behaviors. Here, we briefly discuss the optical properties, the synthetic routes and the analytical applications of these nanoparticles. [ABSTRACT FROM AUTHOR]

Thispaper describes a general method to generate noble metal nanoparticles(NPs) with polymer coatings. One of the widely used approaches tostabilize NPs in aqueous solution involves wrapping NPs with amphiphilicpolymers. This methodology has been extensively employed for polymercoating of small hydrophobic NPs (diameter of inorganic core <20 nm), thereby enabling phase transfer of NPs from an organic solventto aqueous solution. The polymer coating approach is herein extendedto NPs originally synthesized in aqueous solution by a two-step method.First, NPs are subjected to aqueous-to-organic phase transfer. Thephase transfer protocol is demonstrated for NPs made of differentmaterials (Au and Ag), sizes (up to 100 nm), and shapes (spheres,rods, and flat-triangular prisms). Second, NPs are coated with anamphiphilic polymer. The colloidal stability of a variety of the newlydesigned NPs is assayed against different media of biological relevance.In preliminary cellular studies, the biocompatibility of polymer coatedAu NPs is investigated in different cell lines. [ABSTRACT FROM AUTHOR]

X-ray fluorescence imaging (XFI) is a non-invasive detection method of small quantities of elements, which can be excited to emit fluorescence x-ray photons upon irradiation with an incident x-ray beam. In particular, it can be used to measure nanoparticle uptake in cells and tissue, thus making it a versatile medical imaging modality. However, due to substantially increased multiple Compton scattering background in the measured x-ray spectra, its sensitivity severely decreases for thicker objects, so far limiting its applicability for tracking very small quantities under in-vivo conditions. Reducing the detection limit would enable the ability to track labeled cells, promising new insights into immune response and pharmacokinetics. We present a synchrotron-based approach for reducing the minimal detectable marker concentration by demonstrating the feasibility of XFI for measuring the yet inaccessible distribution of the endogenous iodine in murine thyroids under in-vivo conform conditions. This result can be used as a reference case for the design of future preclinical XFI applications as mentioned above. [ABSTRACT FROM AUTHOR]

A substantial increase in engineered nanoparticles in consumer products has been observed, heightening human and environmental exposure. Inhalation represents the primary route of human exposure, necessitating a focus on lung toxicity studies. However, to avoid ethical concerns the use of in vitro models is an efficient alternative to in vivo models. This study utilized an in vitro human alveolar barrier model at air-liquid-interface with four cell lines, for evaluating the biological effects of different gold nanoparticles. Exposure to PEGylated gold nanospheres, nanorods, and nanostars did not significantly impact viability after 24 h, yet all AuNPs induced cytotoxicity in the form of membrane integrity impairment. Gold quantification revealed cellular uptake and transport. Transcriptomic analysis identified gene expression changes, particularly related to the enhancement of immune cells. Despite limited impact, distinct effects were observed, emphasizing the influence of nanoparticles physicochemical parameters while demonstrating the model's efficacy in investigating particle biological effects. • The use of an in vitro tetra-culture model allows to characterize the biological effects of three Au NPs at molecular level. • Coupling the in vitro tetra-culture model at ALI with the VitroCell system ensures a simplified in vitro alveolar septum. • The shape of ENM influences the molecular response of the in vitro tetra-culture model. [ABSTRACT FROM AUTHOR]

We report here titanium dioxide (TiO 2) and silver-doped titanium dioxide (Ag/TiO 2) nanofibers in a polyvinyl pyrrolidone (PVP) matrix. The unique hygroscopic nature of PVP enabled better networking of ethanol-dissolved precursors. X-ray diffraction (XRD) and RAMAN spectroscopy were used to study the phase transformation of the TiO 2 nanofibers due to doping, while field emission scanning electron microscopy (FE-SEM) provided the surface morphology. The Ag/TiO 2 nanofibers transformed from anatase to rutile phase, resulting in better conductive and photocatalytic properties. Dielectric studies suggested phase transformation related charge delocalization and enhanced mobility with increasing Ag content. The photocatalytic properties of the Ag/TiO 2 nanofibers were observed via degradation of Congo Red (CR). The increasing Ag content and conversion to the rutile phase enhanced the degradation efficiency from 36 to 92% under Ultra-violet (UV)-light irradiation. Schematic representation of Congo red's photodegradation using Ag/TiO 2 nanofibers. [Display omitted] • Silver doped TiO 2 nanofibers were fabricated by electrospinning technique. • Silver doping helped tune the phases of TiO 2 nanofibers. • Successful degradation of congo red was achieved with all nanofibers. • Experimental data fitted well according to pseudo-first-order kinetics. • The 92% of removal efficiency was achieved within 180 min of contact time. [ABSTRACT FROM AUTHOR]

Abstract: CdTe nanocrystals capped by short-chain thiol molecules can easily be prepared in aqueous solution, possess a single narrow emission band and can potentially be used as luminescence sensors and ions probes. We report the effect of pH and various ions, including physiology important cations such as calcium(II), manganese(II) and iron(III), on the luminescence intensity of CdTe nanocrystals capped by thioglycolic acid. Quenching of luminescence of CdTe nanocrystals by Ag(I)-cations points out their use in cellular studies as fluorescent labels and quenching agents, respectively. Micromolar amounts of Hg2+ ions caused quenching of the emission of CdTe nanocrystals, while at increasing Hg2+ concentration alloyed Cd x Hg1−x Te nanocrystals were formed, followed by appearance of a near-infrared luminescence band. Luminescence of both bare CdTe nanocrystals and CdTe nanocrystals embedded into polymer microcapsules was found to be pH sensitive within the pH range of 4–6. [Copyright &y& Elsevier]

Advances in nanofabrication methods have enabled the tailoring of new strategies towards the controlled production of nanoparticles with attractive applications in healthcare. In many cases, their characterisation remains a big challenge, particularly for small-sized functional nanoparticles of 5 nm diameter or smaller, where current particle sizing techniques struggle to provide the required sensitivity and accuracy. There is a clear need for the development of new reliable characterisation approaches for the physico-chemical characterisation of nanoparticles with significant accuracy, particularly for the analysis of the particles in the presence of complex biological fluids. Herein, we show that the Differential Centrifugal Sedimentation can be utilised as a high-precision tool for the reliable characterisation of functional nanoparticles of different materials. We report a method to correlate the sedimentation shift with the polymer and biomolecule adsorption on the nanoparticle surface, validating the developed core–shell model. We also highlight its limit when measuring nanoparticles of smaller size and the need to use several complementary methods when characterising nanoparticle corona complexes. [ABSTRACT FROM AUTHOR]

Nanostructured silica (SiO2)-based materials are attractive carriers for the delivery of bioactive compounds into cells. In this study, we developed hollow submicrometric particles composed of SiO2 capsules that were separately loaded with various bioactive molecules such as dextran, proteins, and nucleic acids. The structural characterization of the reported carriers was conducted using transmission and scanning electron microscopies (TEM/SEM), confocal laser scanning microscopy (CLSM), and dynamic light scattering (DLS). Moreover, the interaction of the developed carriers with cell lines was studied using standard viability, proliferation, and uptake assays. The submicrometric SiO2-based capsules loaded with DNA plasmid encoding green fluorescence proteins (GFP) were used to transfect cell lines. The obtained results were compared with studies made with similar capsules composed of polymers and show that SiO2-based capsules provide better transfection rates on the costs of higher toxicity. [ABSTRACT FROM AUTHOR]

A recombinant HALO-GFP fusion protein was designed and isolated to demonstrate the feasibility of controlling the number and orientation of protein ligands to be conjugated on colloidal gold nanoparticles. AuNPs functionalized with exactly one or exactly two GFP molecules exhibited fully preserved functionality of the protein. The method is very straightforward and generally provides highly bioactive nanoparticle–protein conjugates. [ABSTRACT FROM AUTHOR]

Im letzten Jahrzehnt gab es eine große Anzahl publizierter zweidimensionaler und zeitunabhängiger In‐vitro‐Studien über die Aufnahme kolloidaler Nano‐ und Mikropartikel in Zellen. In diesem Kurzaufsatz werden unterschiedliche angewandte Methoden solcher Untersuchungen zusammengefasst und kritisch diskutiert. Ergänzende experimentelle Daten erlauben einen direkten Vergleich zwischen diesen angewandten Techniken. Das Hauptaugenmerk wird darauf liegen, quantitative Parameter aus solchen Studien zu gewinnen, in denen mehrere verschiedene experimentelle Messmethoden genutzt wurden, mit dem Ziel eine bessere Vergleichbarkeit der Daten zu gewährleisten. [ABSTRACT FROM AUTHOR]

There is a large number of two‐dimensional static in vitro studies about the uptake of colloidal nano‐ and microparticles, which has been published in the last decade. In this Minireview, different methods used for such studies are summarized and critically discussed. Supplementary experimental data allow for a direct comparison of the different techniques. Emphasis is given on how quantitative parameters can be extracted from studies in which different experimental techniques have been used, with the goal of allowing better comparison. [ABSTRACT FROM AUTHOR]

The article offers information on noninvasive deep brain stimulation and how it can be triggered. Topics discussed include the use of light-gated ion channels to modify neurons, the role of neurotransmitters the communication between neurons, and the use of upconverting nanoparticles (NPs) in the stimulation process.

Inorganic CdSe/ZnS core-shell quantum dots have been coated with amphiphilic polymers in order to enable their transfer to aqueous solutions. Additionally, ATTO-dye molecules have been embedded in the polymer shell. In this geometry ATTO dye acts as acceptor of the quantum dot donors' excitation. The energy transfer dynamics has been investigated in detail within the system by steady state and time-resolved optical spectroscopy. Radiative and nonradiative transfer processes dominate the photoluminescence properties of the quantum dots and dye molecules. Choosing different sizes of the quantum dots allowed for tuning the spectral overlap between the semiconductor dot emission and dye absorption. The experimental results have been described within a kinetic model which enables precisely to reveal the respective contributions of reabsorption and radiationless transfer rates. The distance dependence of quantum efficiencies and transfer rates shows that radiationless transfer is the more dominating the smaller the distance between the core of the nanoparticles and the dye molecules. [ABSTRACT FROM AUTHOR]

A plasmonic core–shell gold nanostar/zeolitic‐imidazolate‐framework‐8 (ZIF‐8) nanocomposite was developed for the thermoplasmonic‐driven release of encapsulated active molecules inside living cells. The nanocomposites were loaded, as a proof of concept, with bisbenzimide molecules as functional cargo and wrapped with an amphiphilic polymer that prevents ZIF‐8 degradation and bisbenzimide leaking in aqueous media or inside living cells. The demonstrated molecule‐release mechanism relies on the use of near‐IR light coupled to the plasmonic absorption of the core gold nanostars, which creates local temperature gradients and thus, bisbenzimide thermodiffusion. Confocal microscopy and surface‐enhanced Raman spectroscopy (SERS) were used to demonstrate bisbenzimide loading/leaking and near‐IR‐triggered cargo release inside cells, thereby leading to DNA staining. [ABSTRACT FROM AUTHOR]

A plasmonic core–shell gold nanostar/zeolitic‐imidazolate‐framework‐8 (ZIF‐8) nanocomposite was developed for the thermoplasmonic‐driven release of encapsulated active molecules inside living cells. The nanocomposites were loaded, as a proof of concept, with bisbenzimide molecules as functional cargo and wrapped with an amphiphilic polymer that prevents ZIF‐8 degradation and bisbenzimide leaking in aqueous media or inside living cells. The demonstrated molecule‐release mechanism relies on the use of near‐IR light coupled to the plasmonic absorption of the core gold nanostars, which creates local temperature gradients and thus, bisbenzimide thermodiffusion. Confocal microscopy and surface‐enhanced Raman spectroscopy (SERS) were used to demonstrate bisbenzimide loading/leaking and near‐IR‐triggered cargo release inside cells, thereby leading to DNA staining. [ABSTRACT FROM AUTHOR]

Nanoparticles modified with ligands for specific targeting towards receptors expressed on the surface of target cells are discussed in literature towards improved delivery strategies. In such concepts the ligand density on the surface of the nanoparticles plays an important role. How many ligands per nanoparticle are best for the most efficient delivery? Importantly, this number may be different for in vitro and in vivo scenarios. In this review first viruses as "biological" nanoparticles are analyzed towards their ligand density, which is then compared to the ligand density of engineered nanoparticles. Then, experiments are reviewed in which in vitro and in vivo nanoparticle delivery has been analyzed in terms of ligand density. These results help to understand which ligand densities should be attempted for better targeting. Finally synthetic methods for controlling the ligand density of nanoparticles are described. Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract Tremendous efforts have been devoted to the development of future nanomedicines that can be specifically designed to incorporate responsive elements that undergo modification in structural properties upon external triggers. One potential use of such stimuli-responsive materials is to release encapsulated cargo upon excitation by an external trigger. Today, such stimuli-response materials allow for spatial and temporal tunability, which enables the controlled delivery of compounds in a specific and dose-dependent manner. This potentially is of great interest for medicine (e.g. allowing for remotely controlled drug delivery to cells, etc.). Among the different external exogenous and endogenous stimuli used to control the desired release, light and magnetic fields offer interesting possibilities, allowing defined, real time control of intracellular releases. In this review we highlight the use of stimuli-responsive controlled release systems that are able to respond to light and magnetic field triggers for controlling the release of encapsulated cargo inside cells. We discuss established approaches and technologies and describe prominent examples. Special attention is devoted towards polymer capsules and polymer vesicles as containers for encapsulated cargo molecules. The advantages and disadvantages of this methodology in both, in vitro and in vivo models are discussed. An overview of challenges associate with the successful translation of those stimuli-responsive materials towards future applications in the direction of potential clinical use is given. Graphical abstract Release of encapsulated molecular cargo upon (external) triggers. Unlabelled Image [ABSTRACT FROM AUTHOR]

[Display omitted] The therapeutic and diagnostic effects of nanoparticles highly depend on the efficiency of their delivery to targeted tissues, such as tumors. The size of nanoparticles, among other characteristics, plays a crucial role in determining their tissue penetration and retention. Small nanoparticles may penetrate deeper into tumor parenchyma but are poorly retained, whereas large ones are distributed around tumor blood vessels. Thus, compared to smaller individual nanoparticles, assemblies of such nanoparticles due to their larger size are favorable for prolonged blood circulation and enhanced tumor accumulation. Upon reaching the targeted tissues, nanoassemblies may dissociate at the target region and release the smaller nanoparticles, which is beneficial for their distribution at the target site and ultimate clearance. The recent emerging strategy that combines small nanoparticles into larger, biodegradable nanoassemblies has been demonstrated by several groups. This review summarizes a variety of chemical and structural designs for constructing stimuli-responsive disintegrable nanoassemblies as well as their different disassembly routes. These nanoassemblies have been applied as demonstrators in the fields of cancer therapy, antibacterial infection, ischemic stroke recovery, bioimaging, and diagnostics. Finally, we summarize stimuli-responsive mechanisms and their corresponding nanomedicine designing strategies, and discuss potential challenges and barriers towards clinical translation. [ABSTRACT FROM AUTHOR]

Understanding the interaction of nanoparticles with proteins and how this interaction modifies the nanoparticles’ surface is crucial before their use for biomedical applications. Since fluorinated materials are emerging as potential imaging probes and delivery vehicles, their interaction with proteins of biological interest must be studied in order to be able to predict their performance in real scenarios. It is known that fluorinated planar surfaces may repel the unspecific adsorption of proteins but little is known regarding the same process on fluorinated nanoparticles due to the scarce examples in the literature. In this context, the aim of this work is to propose a simple and fast methodology to study fluorinated nanoparticle-protein interactions based on interfacial surface tension (IFT) measurements. This technique is particularly interesting for fluorinated nanoparticles due to their increased hydrophobicity. Our study is based on the determination of IFT variations due to the interaction of quantum dots of ca. 5 nm inorganic core/shell diameter coated with fluorinated ligands (QD_F) with several proteins at the oil/water interface. Based on the results, we conclude that the presence of QD_F do not disrupt protein spontaneous film formation at the oil/water interface. Even if at very low concentrations of proteins the film formation in the presence of QD_F shows a slower rate, the final interfacial tension reached is similar to that obtained in the absence of QD_F. The differential behaviour of the studied proteins (bovine serum albumin, fibrinogen and apotransferrin) has been discussed on the basis of the adsorption affinity of each protein towards DCM/water interface and their different sizes. Additionally, it has been clearly demonstrated that the proposed methodology can serve as a complementary technique to other reported direct and indirect methods for the evaluation of nanoparticle-protein interactions at low protein concentrations. [ABSTRACT FROM AUTHOR]

Abstract: Self‐assembly of nanoparticles provides unique opportunities as nanoplatforms for controlled delivery. By exploiting the important role of noncovalent hydrophobic interactions in the engineering of stable assemblies, nanoassemblies were formed by the self‐assembly of fluorinated quantum dots in aqueous medium through fluorine–fluorine interactions. These nanoassemblies encapsulated different enzymes (laccase and α‐galactosidase) with encapsulation efficiencies of ≥74 %. Importantly, the encapsulated enzymes maintained their catalytic activity, following Michaelis–Menten kinetics. Under an acidic environment the nanoassemblies were slowly disassembled, thus allowing the release of encapsulated enzymes. The effective release of the assayed enzymes demonstrated the feasibility of this nanoplatform to be used in pH‐mediated enzyme delivery. In addition, the as‐synthesized nanoassemblies, having a diameter of about 50 nm, presented high colloidal stability and fluorescence emission, which make them a promising multifunctional nanoplatform. [ABSTRACT FROM AUTHOR]