Nanoparticles In Aqueous Solution Research Articles

A novel nanoparticle fluorescent probe based on a water-soluble conjugated polymer for real-time monitoring of ATP fluctuation and configuration of the Golgi apparatus during the inhibition of glycolysis

BackgroundAdenosine 5′-triphosphate (ATP) plays an important role in cell metabolism and has been regarded as an indicator of cell survival and damage. Golgi apparatus participates in the signal transduction processes of substance transport, ion homeostasis and stress when extracellular substances enter cells. Till now, there is no fluorescent probe for monitoring Golgi ATP level fluctuation and visualizing the configuration change of the Golgi apparatus during the inhibition of glycolysis. ResultsHerein, we report the synthesis of a novel water-soluble cationic polythiophene derivative (PEMTEA) that can be employed as a fluorescent sensor for measuring ATP in the Golgi apparatus. PEMTEA self-assembles into PT-NP nanoparticles in aqueous solution with a diameter of approximately 2 nm. PT-NP displays high sensitivity and superb selectivity towards ATP with a detection limit of 90 nM and a linear detection range from 0 to 3.0 μM. The nanoparticles show low toxicity to HepG2 cells and good photostability in the Golgi apparatus. With the stimulation of Ca2+, PT-NP was practically applied to real-time monitor of endogenous ATP levels in the Golgi apparatus through fluorescence microscopy. Finally, we studied the relationship between the concentration of ATP and configuration of the Golgi apparatus during the inhibition of glycolysis using PT-NP. SignificanceWe have demonstrated that PT-NP can not only indicate the fluctuation and distribution of ATP in the Golgi apparatus, but also give the information of the configuration change of the Golgi apparatus at the single-cell level during the inhibition of glycolysis.

Synthesis of multi-responsive poly(NIPA-co-DMAEMA)-PBA hydrogel nanoparticles in aqueous solution for application as glucose-sensitive insulin-releasing nanoparticles

Synthesis of multi-responsive poly(NIPA-co-DMAEMA)-PBA hydrogel nanoparticles in aqueous solution for application as glucose-sensitive insulin-releasing nanoparticles

Honey-assisted synthesis and properties of silver nanoparticles in aqueous solution and inside supramolecular aggregates. The Cassyopea® effect

In this work we introduce supramolecular aggregates named Cassyopea®, acronym of combined and sustainable synthesis of payload-enriched aggregates from the method used for their preparation. Herein, Cassyopea® were described as reactors and carriers for silver nanoparticles (AgNPs) obtained from honey according to eco-friendly conditions. Spherical, monodisperse, and negatively charged NewAgNPs®, acronym of natural ecosustainable way AgNPs, having a mean size of 30 nm and high stability over time were prepared in aqueous solution. The successful synthesis of NewAgNPs® inside Cassyopea® was demonstrated by UV–vis spectroscopy, emission scanning electron microscopy (FE-SEM) and energy-dispersive X-ray (EDX) analysis. The protective effect of Cassyopea® on NewAgNPs® against the oxidation induced by H2O2 was kinetically determined in the Fenton-like reaction suggesting that the investigated nanoparticles tend to be located in the aqueous core of the investigated aggregates. Furthermore, microbiological assays revealed the tendency of Cassyopea® to preserve the biological activity of NewAgNPs® against Gram-positive and Gram-negative bacteria. The preparation of silver nanoparticles directly into supramolecular aggregates instead of their loading in preformed state is unprecedented, and the data reported for NewAgNPs® and Cassyopea® highlight promising applications in nanotechnology.

Polyethylene glycol modified protamine-chlorin e6 conjugate nanoparticles for enhanced cancer photodynamic therapy

Photodynamic therapy attracts great attention in cancer treatment due to its minimal invasiveness, good tolerance and specific cancer targeting. However, most of tumors are hypoxic and the tumors will become more hypoxic after photodynamic therapy, which might cause the poor prognosis by inducing tumor angiogenesis. In the present work, polyethylene glycol modified protamine-chlorin e6 conjugate (PEG-protamine-Ce6) was synthesized for enhanced cancer photodynamic therapy. PEG-protamine-Ce6 was synthesized by conjugating protamine with methoxypolyethylene glycol acetaldehyde and Ce6 sequentially. The in vitro studies show that PEG-protamine-Ce6 self-assembles into nanoparticles in aqueous solution with uniform size (∼200 nm), positive zeta potential and spherical morphology. The in vitro cell studies show that PEG-protamine-Ce6 nanoparticles exhibit enhanced cellular uptake amount, intracellular ROS level elevation upon laser irradiation, cell apoptosis and photocytotoxicity as compared to Ce6. The in vivo studies show that PEG-protamine-Ce6 nanoparticles exhibit enhanced antitumor effect as compared to Ce6 upon laser irradiation. PEG-protamine-Ce6 with laser irradiation not only inhibits tumor cell proliferation, but also inhibits tumor angiogenesis by suppression of VEGF expression, whereas Ce6 with laser irradiation promotes tumor angiogenesis by enhancing VEGF expression. PEG-protamine-Ce6 nanoparticles developed in this work offer a novel nanomedicine for enhancing cancer photodynamic therapy.

Capillary Electrophoretic Characterization of Platinum and Silver Nanoparticles in Aqueous Solution Prepared by a Solution Plasma Process

Capillary Electrophoretic Characterization of Platinum and Silver Nanoparticles in Aqueous Solution Prepared by a Solution Plasma Process

Electrochemical properties of magnetite nanoparticles supported on carbon paste electrode in various electrolyte solutions: A study by cyclic voltammetry

Abstract Electrochemical properties of magnetite nanoparticles supported on carbon paste electrodes were investigated by means of cyclic voltammetry. The measurements were performed for bare and coated with citrate magnetite nanoparticles in aqueous solutions of various electrolytes: NaCl, NaClO4, and Na2HPO4. Cyclic voltammetry curves obtained on bare and citrate functionalized Fe3O4 nanoparticles are rather similar indicating that the electrochemical properties of the magnetite nanoparticles are not significantly affected by the citrate coating. Cyclic voltammetry scans reveal the formation of metallic iron below −1.2 V. The defective structure of the oxide phases formed by oxidation of metallic iron seems to play an important role in the chemisorption of chloride ions and their subsequent oxidation. Graphical Abstract

An insight into the photocatalytic degradation of the antibiotic rifampicin by titanium dioxide nanoparticles in aqueous solution under UV light irradiation

An insight into the photocatalytic degradation of the antibiotic rifampicin by titanium dioxide nanoparticles in aqueous solution under UV light irradiation

In-situ SERS detection strategy based on electric charge adsorption between nanoparticles formed with an effective hetero-charged electric field for detecting polystyrene nanoparticle in aqueous solution

The in-situ detection of nanoplastics (NP) has attracted a great deal of attention due to their poisonous properties for both human beings or marine organism. Surface Enhanced Raman Scattering (SERS) is utilized to distinguish a typical NP, polystyrene (PS). However, PS NPs in aqueous solution could barely be detected through SERS. In this research, a SERS detection strategy based on the electric charge adsorption of the designed hetero-charged PS NPs and AuNPs was brought out. Under this strategy, the intensity of the Raman signal in aqueous solution was strong enough to identify PS NPs, and the lowest detection line was 0.08 wt%. All result indicated that once the spacing distance lower than 2 nm would have a great SERS performance. Moreover, the particles relationship of this SERS detection discovered by the FETEM results was different from the traditional SERS detection strategy. The SERS performance was related to the number of the PS NPs surrounded the AuNPs, and the intensity of the superposition electric field would have a progressive linear relationship with the number of the charged surrounded PS NPs. All these principle and phenomena would suit for further research of the MPs/NPs in marine pollution or detection biomarker in vivo directly.

Supramolecular nanoarchitectonics of propionylated polyrotaxanes with bulky nitrobenzyl stoppers for light-triggered drug release.

Cyclodextrin (CD)-based polyrotaxanes (PRXs) are supramolecular polymers comprising multiple CDs mechanically interlocked onto a linear polymer chain by capping the polymer ends with bulky stoppers. Among various PRX derivatives, propionylated PRXs (Pr-PRXs) composed of propionylated α-CD and high molecular-weight poly(ethylene glycol) (PEG) form self-assembled nanoparticles in aqueous solution through hydrophobic interactions. Although Pr-PRX nanoparticles can encapsulate hydrophobic drugs in their hydrophobic domains, their release rate is limited. To improve the efficiency of drug release from Pr-PRX nanoparticles, ultraviolet (UV) light-dissociable Pr-PRXs were designed using 4,5-dimethoxy 2-nitrobenzyl groups as UV-cleavable bulky stopper molecules to facilitate UV-induced drug release. Photodegradable Pr-PRX (Pr-PD-PRX) was synthesized, and its UV-induced dissociation was examined. Pr-PD-PRX was completely dissociated via UV irradiation (365 nm) for 30 min. Additionally, Pr-PD-PRX nanoparticles encapsulating hydrophobic drugs collapsed upon UV irradiation, which promoted the release of the encapsulated drugs compared to non-degradable Pr-PRX nanoparticles. UV irradiation of drug-loaded Pr-PD-PRX nanoparticles resulted in higher cytotoxicity than non-irradiated Pr-PD-PRX and non-degradable Pr-PRX. Consequently, designing photodegradable PRX-based nanoparticles provides new insights into developing photoresponsive drug carriers and smart biomedical materials.

Design of donor-acceptor conjugated polymers based on diketopyrrolopyrrole for NIR-II multifunctional imaging.

Diketopyrrolopyrrole (DPP) is an excellent photosensitizer and photothermal agent with the advantages of good planarity, strong electron affinity, high electron mobility, easy purification, easy structural modification and high molar absorption coefficient. It is regarded as one of the ideal choices for the design and synthesis of efficient organic photovoltaic materials. Therefore, two kinds of donor-acceptor (D-A) conjugated polymers were designed and synthesized with DPP as the acceptor, and their optical properties and applications in the near-infrared region were studied. The quantum yield (QY) of PBDT-DPP is 0.46%, and the highest temperature reached within 10 minutes after irradiation with a 660 nm laser is 60 °C. Another polymer, EDOT-DPP, has a QY of 0.48%, and its semiconductor polymer nanoparticle aqueous solution can reach 60 °C within 12 minutes under laser irradiation, achieving photothermal treatment of nude mice tumors. Both polymer NPs have good biocompatibility and promising applications in bioimaging and photothermal therapy.

Biosynthesis of Cd and Ru doped CeO2 nanoparticles with enhanced biomedical applications

This research work focused on the bio synthesis of CeO2, Cd doped CeO2, and Ru doped CeO2 nanoparticles using vigna radiata extract. For the assessment of all of the synthesized materials, we employed spectral methods like UV-DRS, FTIR, XRD, FESEM, and EDAX. We investigate how a model protein, bovine serum albumin (BSA), interacts with nanoparticles in aqueous solutions using UV–visible absorption and emission spectra using phosphate buffer (pH = 7.4). The quenching rate constants (Kq) is bigger than the maximal diffusion constant (2.0 x 1010 M−1s−1) of biomolecules resulting prepared nanoparticles are involved static quenching process. The sensing of glucose also carried out via cyclic voltammetry and Cd/CeO2 NPs exhibit better sensing towards 19 μM of glucose at pH 13.

Croconaine conjugated cationic polymeric nanoparticles for NIR enhanced bacterial killing

Light-triggered treatment approach has been regarded as an effective option for sterilization due to noninvasiveness, limited drug resistance, and minimized adverse effects. Herein, we designed and synthesized a functionalized cationic polymer, CR-PQAC, with croconaine bridging agent and quaternary ammonium groups for photothermal enhanced antimicrobial therapy under near-infrared irradiation. The quaternary ammonium group on the pendent chain endowing CR-PQAC the ability to effectively bind to bacteria. The CR-PQAC could self-assembles into micellar nanoparticles in aqueous solution, which exhibited strong absorption in the near-infrared (NIR) region, excellent photostability, and photothermal conversion efficiency of up to 43.8 %. Notably, the CR-PQAC nanoparticles presented remarkable antibacterial activity against both methicillin-resistant Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacteria with 808 nm laser irradiation. Moreover, the developed CR-PQAC has negligible dark cytotoxicity and good hemolytic compatibility against mammalian cells. Both in vitro and in vivo studies have demonstrated that the desirable antibacterial efficacy of CR-PQAC was obtained. Therefore, the proposed CR-PQAC may be a promising antimicrobial agent for NIR-enhanced killing bacterial.

Combined application of SiO2 and TiO2 nanoparticles enhances growth characters, physiological attributes and essential oil production of Coleus aromatics Benth

Nanoparticles (NPs) have gained considerable interest among researchers in the field of plant biology, particularly in the agricultural sector. Among the numerous NPs, the individual application of silicon (Si) or titanium (Ti), in their oxide forms, had a positive influence on growth, physiochemical and yield attributes of plants. However, the synergetic application of both these NPs has not been studied yet. Therefore, the current study was aimed to investigate the effect of combined application of silicon dioxide (SiO2) and titanium dioxide (TiO2) NPs on the growth characters, physiological parameters, and essential oil quality and production of Coleus aromatics Benth. Aqueous solutions of nanoparticles were applied to the foliage of the plants at varying combinations (Si50+Ti50, Si100+Ti50, Si100+Ti100, Si200+Ti100, Si100+Ti200 and Si200+Ti200 mg L−1). Various morpho-physiological, biochemical and yield attributes were assessed at 120 days after planting. The results demonstrated that both Si and Ti NPs improved the growth and photosynthetic efficiency in a dose dependent manner. The best results were obtained by the combined application of Si100+Ti100 mg L−1, and thereafter, the values declined progressively. The maximum improvement in fresh weight (39.5 %) and dry weight (40.8 %) of shoot, fresh weight (45.7 %) and dry weight (49.4 %) of root was observed as compared to respective controls. Moreover, the exogenous application of Si100+Ti100 mg L−1 increased photosynthetic attributes such as total content of chlorophyll (41.7 %), carotenoids (43.7 %), chlorophyll fluorescence (7.1 %), and carbonic anhydrase (23.8 %). All of these contributed to the highest accumulation in the content (129.0 %) and yield (215.5 %) of essential oil (EO), in comparison to the control. Thus, results encouraged the use of SiO2 and TiO2 NPs to be applied in combined form to boost the essential oil production of Coleus aromaticus. The findings of this study may serve agronomists to determine the optimal concentrations of NPs for enhanced production of bioactive compounds with a wide range of industrial applications.

Single Elementary Charge Fluctuations on Nanoparticles in Aqueous Solution.

100 years ago, in 1923, the Nobel prize in physics was awarded for measurement of the unit charge. In addition to a profound impact on contemporary physics, this discovery has reshaped our understanding of charge-based interactions in chemistry and biology, ranging from oxidation and ionization to protein folding and metabolism. In a liquid, the discrete nature of the electric charge becomes prominent at the nanoscale when a charge carrier is exchanged between a molecule or a nanoparticle and the surrounding medium. However, our ability to observe the dynamics of such interactions at the level of a single elementary charge is limited due to the abundance of ions in water. Here, we report on the observation of single binding-unbinding events with elementary charge resolution at the surface of a nanoparticle suspended in water. Discrete steps in the electrical charge are revealed by analyzing the motion of optically trapped nanoparticles under the influence of an applied sinusoidal electric field. The measurements are sufficiently fast and long to observe individual (dis)charging events that occur on average every 3 s. Our results offer prospective routes for studying the dynamics of diverse chemical and biological phenomena on the nanoscale with elementary charge resolution.

A photoluminescence strategy for detection nanoplastics in water and biological imaging in cells and plants

Nanoplastics exposure poses a significant threat to the environment and human health, and accurate measurement of nanoparticles in aqueous solutions remains challenging. In this work, we synthesized the cationic fluorescent probe 4-[1-Cyano- 2-[4-(Diethylamino)−2-hydroxyphenyl]ethenyl]−1-ethylpyridinium (PCP) through a straightforward procedure for the rapid and accurate detection and labeling of nanoplastics in aqueous solutions. PCP binds to nanoplastics through electrostatic and hydrophobic interactions with restricted intramolecular rotation and exhibits enhanced fluorescence emission. Using carboxylation-modified polystyrene nanoplastics as a model, PCP could accurately detect concentrations as low as 0.525 mg∙L−1 in aqueous solution and perform wash-free semi-quantitative direct observation. The method demonstrated good reproducibility and recovery in actual sample spiking experiments. In addition, PCP-labeled nanoplastics were successfully used to visualize the uptake and distribution of cells and Arabidopsis thaliana when exposed to different concentrations of nanoplastics. This work provides a simple and sensitive method for efficiently identify, track, and quantify nanoplastics without requiring additional pretreatment and complex instrumentation, making it an ideal tool for accurately quantifying nanoplastics in aqueous solutions and studying the biological interactions of nanoplastics.

Near-Infrared Self-Assembled Hydroxyl Radical Generator Based on Photoinduced Cascade Electron Transfer for Hypoxic Tumor Phototherapy.

The hydroxyl radical (•OH) is an extremely potent reactive oxygen species that plays a crucial role in photooxidations within the realm of hypoxic tumor therapy. However, the current methods for •OH photogeneration typically rely on inorganic materials that require UV/vis light excitation. Consequently, photogenerators based on organic molecules, especially those utilizing near-infrared (NIR) light excitation, are rare. In this study, the concept of photoinduced cascade charge transfer (PICET), which utilizes NIR heavy-atom-free photosensitizers (ANOR-Cy5) to generate •OH is introduced. The ANOR-Cy5 photosensitizer, with its flexible hydrophobic structure, enables the formation of nanoparticles in aqueous solutions through molecular assembly. PICET involves a symmetry-breaking charge separation-induced localized charge-separated state, transitioning to a delocalized charge-separated state, which governs the efficiency of •OH generation. Thanks to the oxygen-independent nature of •OH generation and its robust oxidative properties, the ANOR-Cy5-based photosensitizer demonstrates highly effective photoinduced anti-cancer effects, even under severely hypoxic conditions. This discovery emphasizes the potential for achieving •OH photogeneration using a single organic molecule through the engineering of molecular self-assembly, thereby opening up new possibilities for phototherapy and beyond.

The Analytical Application of Quenching Phenomena of CdTe Quantum Dot Nanoparticles

This paper is devoted to the synthesis and application of CdTe quantum dot (QD) nanoparticles covered with organic ligands containing a thiol group, mostly mercaptopropionic acid (MPA) and glutathione (GSH). The simple one-step synthetic procedure was optimized to prepare greater quantities of nanoparticles for analytical purposes. The prepared CdTe QD nanoparticles were characterized by various analytical techniques, and their interaction with some metal ions (Cu(II), Pb(II), and Hg(II)) was studied by using luminescence spectroscopy in both steady-state and time-resolved modes. The mathematical analysis of the quenching effect of Cu(II) ions on the luminescence of CdTe QD nanoparticles shows that the static contribution is mostly responsible for the overall effect, but experimental conditions, such as pH, ionic strength, or the concentration of nanoparticles in aqueous solution, could also be important. The presence of metal ions in the form of a metal complex species could play an important role, and this phenomenon could be used to tune the selectivity of the quenching process. These findings have been utilized for the development of an analytical procedure for the detection and quantitative analysis of Cu(II) and Pb(II) ions in environmental water samples. In practice, this procedure could be easily implemented in a microplate format to increase throughput.

Hierarchically Structured and Highly Dispersible MOF Nanozymes Combining Self-Assembly and Biomineralization for Sensitive and Persistent Chemiluminescence Immunoassay.

Metal-organic frameworks (MOF) are promising candidates for the construction of artificial nanozymes and have found applications in many fields. However, the preparation of nanosized MOF materials with high performance and good dispersibility is still a big challenge and is in great demand as signal labels for immunoassays. In this work, hierarchically structured and highly dispersible MOF nanoparticles were facilely prepared in a one-pot method. Self-assembled micelles from PEGylated hematin were used as structured templates to mediate the formation of zeolitic imidazole framework-8 (ZIF-8) nanoparticles in aqueous solution. The encapsulation of micelles in ZIF-8 frameworks produces well-dispersed nanoparticles and generates dual-confinement effects for catalytic hematin. Owing to the hierarchical structures, the formed MOF nanozymes show enhanced peroxidase-like activity and enable persistent chemiluminescence behaviors for the luminol system. Sandwich-type chemiluminescence immunoassays for carcinoembryonic antigen (CEA) were proposed using MOF nanozymes as signal labels, and good analytical performances were achieved. The combination of self-assembly and biomineralization may open new avenues for the development of MOF nanomaterials.

Promoted Charge Separation and Long-Lived Charge-Separated State in Porphyrin-Viologen Dyad Nanoparticles.

Developing light-harvesting systems with efficient photoinduced charge separation and long-lived charge-separated (CS) state is desirable but still challenging. In this study, we designed a zinc porphyrin photosensitizer covalently linked with viologen (ZnP-V) that can be prepared into nanoparticles in aqueous solution. In DMF solution, the monomeric ZnP-V dyads show no electron transfer between the ZnP and viologen units. In contrast, the ZnP-V nanoparticles in aqueous solution show fast charge separation with a CS state lifetime of up to 4.3 ms. This can be attributed to charge hopping induced by aggregation or distance modification between the donor and acceptor induced by electronic interaction. Nevertheless, the lifetime of the CS state is orders of magnitude longer than for molecular aggregates reported previously. The ZnP-V nanoparticles show enhanced photocatalytic hydrogen production as compared to the ZnP nanoparticles and still hold promise for other applications such as photovoltaic devices and photoredox catalysis.

Electrolytic synthesis of metallic aluminum nanoparticles in aqueous solution

Electrolytic synthesis of metallic aluminum nanoparticles in aqueous solution