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A simple heteroleptic iridium(III) photosensitizer, Ir-1, containing two ligands 5-(trifluoromethyl)-2-phenylpyridine (ĈN–CF3) and bipyridine (NN) has for the first time been studied for cocatalys...

International audience; HypothesisPrecise modulation of immuno-inflammatory response is crucial to control periodontal diseases and related systemic comorbidities. The present nanosystem with the controlled-release and cell-penetrating manner enhances the inflammation modulation effects of baicalein in human gingival epithelial cells (hGECs) for better oral healthcare.ExperimentsWe constructed a red-emissive mesoporous silica nanoparticle-based nanosystem with cell-penetrating poly(disulfide) (CPD) capping, through a facile in-situ polymerization approach. It was featured with a glutathione-responsive manner and instant cellular internalization capacity for precisely delivering baicalein intracellularly. Laboratory experiments assessed whether and how the nanosystem per se with the delivered baicalein could modulate immuno-inflammatory responses in hGECs.FindingsThe in-situ polymerized CPD layer capped the nanoparticles and yet controlled the release of baicalein in a glutathione-responsive manner. The CPD coating could facilitate cellular internalization of the nanosystem via endocytosis and thiol-mediated approaches. Notably, the intracellularly released baicalein effectively downregulated the expression of pro-inflammatory cytokines through inhibiting the NF-κB signaling pathway. The nanosystem per se could modulate immuno-inflammatory responses by passivating the cellular response to interlukin-1β. This study highlights that the as-synthesized nanosystem may serve as a novel multi-functional vehicle to modulate innate host response via targeting the NF-κB pathway for precision healthcare.

A uniform nickel film could be coated on crown ether-modified carbon nanotubes (c-CNTs) by electroless deposition. The products CNT@Ni and c-CNT@Ni were oxidized and compressed into CNT@Ni@(NiOH)2 and c-CNT@Ni@(NiOH)2 discs, respectively. The areal and volumetric capacitances of CNT@Ni@(NiOH)2 and c-CNT@Ni@(NiOH)2 were compared and c-CNT@Ni@(NiOH)2 showed a lower resistance.

Second-generation type III-B rotaxane dendrons, equipped with succinimide and acetylene functional groups, were synthesized successfully and characterized by NMR spectroscopy and mass spectrometry. A cell viability study of a dendron with a normal cell line of L929 fibroblast cells revealed no obvious cytotoxicity at a range of 5 to 100 μM. The nontoxic properties of the sophisticated rotaxane dendron building blocks provided a choice of bio-compatible macromolecular machines that could be potentially developed into polymeric materials.

Two new iridium motif linked porphyrins, MBPyZnP-Ir and TBPyZnP-Ir are developed for photocatalytic hydrogen evolution (PHE). The tetra-iridium linked one, TBPyZnP-Ir, displayed the highest H2 production rate (ηH2) of 16.12 mmol g−1 h−1 within 5 h of irradiation, which is over 2.73-fold higher than MBPyZnP-Ir (5.90 mmol g−1 h−1) and much higher than their precursors TBPyZnP (0.12 mmol g−1 h−1) and MBPyZnP (0.06 mmol g−1 h−1) without iridium. The superior ηH2 of TBPyZnP-Ir could be explained by the iridium motifs linked to the porphyrin, stabilizing the triplet states of the porphyrin through intramolecular energy transfer; thus enhancing electron transfer from the triplet photo-excited porphyrin moiety to the cobaloxime co-catalyst and consequently proton reduction.

An increasing number of studies have reported the use of various nanoparticles to encapsulate cisplatin, a frontline chemotherapeutic drug against a broad-spectrum of cancers, for overcoming its inherent drawbacks in clinical applications. Nevertheless, few analytical methods or instruments could provide the precise distribution information on this platinum drug in biological tissues. Herein, we provide the first evidence of applying matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) to assess the spatial distribution of cisplatin released from the cell-penetrating poly(disulfide) (CPD)-modified hollow iron oxide nanoparticles (hFe3O4-MPS-CPD) at the kidneys via an in situ glutathione (GSH) responsive mode. The cisplatin released from the nanoparticles triggered by GSH was successfully examined as [Pt(DDTC)2]+ (m/z 491.01) and [Pt(DDTC)3]+ (m/z 639.04) by MALDI-MS after derivatization using diethyldithiocarbamate. The in situ spatial distribution of [Pt(DDTC)2]+ and [Pt(DDTC)3]+ in the kidneys was then mapped using MALDI-MSI. This study presents an optimized analytical approach to evaluate and map the metallodrug in biological tissue samples in an efficient and convenient manner, offering great assistance in investigating the biodistribution of cisplatin delivered by nanoparticles, and sheds light on facilitating the studies of the pharmacokinetics of cisplatin in biomedical research.

A completely water-soluble, high quantum yield blue-fluorescent benzimidazole derivative (AQ), containing a rigid benzimidazole-thiophene structure, was synthesized. Among 21 metal ions, the fluorescence of AQ was selectively turned off by Cu2+ to form an AQ-Cu2+ ensemble. Thereafter, the fluorescence of the AQ-Cu2+ ensemble was turned on by sulfide (S2-) with high selectivity and sensitivity in pure water solution. In comparison with AQ-Ag+ and AQ-Hg2+ ensembles, AQ-Cu2+ was the only ensemble that was capable of detecting a sulfide anion. Also, the fluorescence intensity of AQ was linearly proportional to the concentration of Cu2+ and S2-. Both Cu2+ and S2- were detected within a minute in vitro. Moreover, AQ worked best in the pH range of 5-10 and had a limit of detection of 50 nM and 354 nM for Cu2+ and S2- respectively. It was employed for the detection of sulfide in human lung cancer A549 cells with low cytotoxicity.

Concerns over the health risks associated with airborne exposure to ultrafine particles [PM0.1, or nanoparticles (NPs)] call for a comprehensive understanding in the interactions of inhaled NPs along their respiratory journey. We prepare a collection of polyethylene glycol-coated gold nanoparticles that bear defined functional groups commonly identified in atmospheric particulates (Au@PEG-X NPs, where X = OCH3, COOH, NH2, OH, or C12H25). Regardless of the functional group, these ∼50 nm NPs remain colloidally stable following aerosolization and incubation in bronchoalveolar lavage fluid (BALF), without pronouncedly crossing the air-blood barrier. The type of BALF proteins adhered onto the NPs is similar, but the composition of protein corona depends on functional group. By subjecting Balb/c mice to inhalation of Au@PEG-X NPs for 6 h, we demonstrate that the intrapulmonary distribution of NPs among the various types of cells (both found in BALF and isolated from the lavaged lung) and the acute inflammatory responses induced by inhalation are sensitive to the functional group of NPs and postinhalation period (0, 24, or 48 h). By evaluating the pairwise correlations between the three variables of "lung-nano" interactions (protein corona, intrapulmonary cellular-level distribution, and inflammatory response), we reveal strong statistical correlations between the (1) fractions of albumin or carbonyl reductase bound to NPs, (2) associations of inhaled NPs to neutrophils in BALF or macrophages in the lavaged lung, and (3) level of total protein in BALF. Our results provide insights into the effect of functional group on lung-nano interactions and health risks associated with inhalation of PM0.1.

An increasing number of studies have reported the use of various nanoparticles to encapsulate cisplatin, a frontline chemotherapeutic drug against a broad-spectrum of cancers, for overcoming its inherent drawbacks in clinical applications. Nevertheless, few analytical methods or instruments could provide the precise distribution information on this platinum drug in biological tissues. Herein, we provide the first evidence of applying matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) to assess the spatial distribution of cisplatin released from the cell-penetrating poly(disulfide) (CPD)-modified hollow iron oxide nanoparticles (hFe

Rotaxane dendrimers with hyperbranched macromolecular interlocked structures and size modulation capacity demonstrate drug binding and release ability upon external stimuli. Mass spectrometry imaging (MSI) can offer the high-throughput screening of endogenous/exogenous compounds. Herein, we reported a novel method to display the

Precise macromolecular recognition and self-sorting are essential in biological systems to maintain life. Herein, we report the self-assembly between one single dendritic macromolecule with discrete molecular weight and one single gold nanoparticle (Au NP) during the in situ growth of the Au NP. This process resembles an artificial, organic, and soft nanohand picking up a growing inorganic hard nanoparticle of a particular size (∼1.4 nm). Discrete 1 : 1 organic–inorganic hybrid nanostructures based on four finger-like dendritic macromolecules with different anchors have been investigated with their ability to wrap up a Au NP of different sizes. Both experimental and theoretical studies demonstrate that the dendrons with different anchoring groups can control the nucleation and growth, and stabilized the sizes of Au NPs. These results highlight the importance of the dendron's anchoring groups in the gold nucleation step before the small gold cluster grows into a Au NP and is then firmly wrapped within the whole dendron. These results provide the fundamental understanding of soft nanomachinery on sorting out nanosized products of particular size and shape.

In this study, the synthesis of [2]rotaxanes as fluorescent metal ion sensors has been demonstrated. [2]Rotaxanes, RA-H·PF6, RRA and RRB, undergo photoelectron transfer resulting in fluorescence quenching. Before the diimine (dynamic covalent bond) reduction on the macrocyclic ring, the dynamic [2]rotaxane RA-H·PF6 can be hydrolyzed and turned fluorescent by trivalent metal ions, giving fluorescence at λmax 424 nm. After reduction of the imines, the reduced [2]rotaxanes RRA and RRB are kinetically stable and highly selective to Au3+ binding among 27 metal ions in a water-compatible (50 vol%) solution with working fluorescence in the range of pH 4–10. 50-Fold and 1.2-fold fluorescence turn-on after addition of Au3+ has been observed for RRA and RRB, respectively. Metal interference on Au3+ detection is insignificant, and thereby the fluorescence intensity is linearly proportional to the concentration of Au3+ until excess. The solid-state crystal structure of RRA shows the mechanically interlocked structure (mechanical bond). The bioimaging experiment of RRB with HeLa cells demonstrates the potential application of these mechanically interlocked molecules for metal ion detection in aqueous media and biological systems.

Type III-C rotaxane dendrimers were synthesized by a divergent approach. Dual shuttling behavior and size modulation were observed from non-methylated/methylated rotaxane dendrimers under the same external stimuli. The biological distribution of dendrimers in C57BL/6J mice determined by MALDI-TOF-MS shows predominant accumulation in the spleen and liver. Drug encapsulations with chlorambucil and lithocholic acid were demonstrated.

Metal–organic framework (MOF)-derived nanostructures exhibit wonderful characteristics and possess broad application potential by modulating the complex composition and inner nanostructure. Although various MOF-based nanocomposites have been successfully developed, a facile method that can easily modulate the structure-dependent chemical components of the MOF-derived hybrids remains a challenge. By coating zeolitic imidazolate framework-8 (ZIF-8) with Au/polydopamine (Au/PDA) via in situ redox-oxidation polymerization of HAuCl4 and dopamine, it was found that the ZIF-8 templates were simultaneously etched off to give Au/PDA hybrid microcapsules with a cubic shape. This one-step sacrificial templating process followed a competing chelation between gold ions and Zn2+ cations to 2-methylimidazole and PDA; thus, both the hollow and the yolk-like hybrid cubic microcapsules were controllably obtained by varying the synthetic dynamics. Owing to the hollow nature, penetrated PDA shell, well-distributed Au nanocrystals, and unique stable nanostructure, the non-spherical Au/PDA hybrid cubic microcapsules showed high performance in catalyzing the reduction of 4-nitrophenol as well as adsorption/release of ibuprofen as a model drug. Moreover, this simple strategy offers a controllable design in developing multifunctional nanocomposites with definite inner nanostructures and activities for nanocatalysis, drug delivery, energy storage etc.

The exploitation of multifunctional nanocomposites as artificial mimetic enzymes has received significant attention. This study reports a novel sandwich-structural magnetic microsphere (Fe3O4@resorcinol/formaldehyde resin–metal@polydopamine), in which ultra-small noble metal nanocrystals can be sandwiched between the resorcinol/formaldehyde resin (RF) and polydopamine (PDA) layers. By changing the metal precursor, various microspheres decorated with mono- or bi-metallic nanocrystals (Pt, Pd, Au, PtAu, etc.) can be obtained. The dual-shelled magnetic microsphere not only provides abundant active sites for noble metal nanocrystals but also effectively restrains aggregation and leaching. The as-prepared Fe3O4@RF–Pt@PDA can efficiently catalyze the oxidation of 3,3,5,5-tetramethylbenzidine (TMB) in the presence of H2O2, which confirms that the as-prepared nanocatalyst shows good peroxidase-like activity. The catalytic activity of Fe3O4@RF–Pt@PDA is dependent on pH and temperature, and the relevant catalytic kinetics follow the Michaelis–Menten behaviors. Moreover, this kind of magnetic microsphere can be further applied for H2O2 and glucose detections and the limit of detection (LOD) is found to be as low as 3.1 μM and 1.36 μM, respectively. Benefiting from a facile preparation process, superior structure, and outstanding catalytic activity, these multifunctional microspheres possess high potential as artificial enzymes in clinical diagnosis, analytical chemistry and environmental fields.

In this paper, we investigated the functional imaging and targeted therapeutic properties of core@multi-shell nanoparticles composed of a superparamagnetic iron oxide (SPIO) core and gold nanorods (GNRs) in the mesoporous silica shells functionalized with folic acid (Fe

A BODIPY-based fluorescent sensor PS with an NO4S2 podand ligand was studied for the selective detection of Pt2+ over 21 cations as well as selected platinum drugs in aqueous medium. The platinum sensor PS shows 28-fold, 22-fold and 14-fold fluorescence turn-on enhancements to Pt2+, cisplatin and nedaplatin, and was thereby employed to detect platinum drugs in A-549 human lung cancer cells.

Mesoporous silica nanoparticles (MSNs), the inorganic nanomaterials with stable physicochemical property and versatile surface functional groups, have been increasingly studied and applied in biomedical field as nanocarriers. There are a limited number of reports on their potential applications in clinical dentistry. Herein, we fabricated the fluorescence-labeled MSNs (RITC-NPs) and investigated for the first time their infiltration profiles in the dentinal tubules of extracted permanent teeth prepared by different irrigation approaches. Ethylenediaminetetraacetic acid (EDTA) enabled removal of the smear layer efficiently and exposure of the dentinal tubules on the root canal walls. Confocal scanning laser microscopy showed that the RITC-NPs could accumulate on the root canal walls, and effectively infiltrate into the dentin. In general, the fluorescence intensity in dentin from EDTA-treated group was much higher than that from the ultrasound-treated group, and stronger red fluorescence was observed at the crown and middle sections than the apical one in the EDTA group. The field-emission gun scanning electron microscopy further confirmed the infiltration effects of RITC-NPs in the dentin, through the patent dentinal tubules. The present findings on the infiltration of MSNs in the root canal system may provide a potential approach for further applying MSN-encapsulated antimicrobials in advanced endodontic therapy.

Many investigations into the interactions between nanoparticles and mammalian cells entail the use of culture systems that do not account for the effect of extracellular mechanical cues, such as compression. In this work, we present an experimental set-up to systematically investigate the combined effects of nanoparticle size and compressive stress on the cellular uptake and intracellular localization of poly(ethylene glycol)-coated gold nanoparticles (Au-PEG NPs). Specifically, we employ an automated micromechanical system to apply defined levels of compressive strain to an agarose gel, which transmits defined amounts of unconfined, uniaxial compressive stress to a monolayer of C2C12 mouse myoblasts seeded underneath the gel without compromising cell viability. Notably, uptake of Au-PEG NPs smaller than 25 nm by compressed myoblasts is up to 5-fold higher than that by uncompressed cells. The optimal compressive stress for maximizing the cellular uptake of sub-25 nm NPs monotonically increases with NP size. With and without compression, the Au-PEG NPs enter C2C12 cells via energy-dependent uptake; they also enter compressed cells via clathrin-mediated endocytosis as the major pathway. Upon cellular entry, the Au-PEG NPs more readily reside in the late endosomes or lysosomes of compressed cells than uncompressed cells. Results from our experimental set-up yield mechanistic insights into the delivery of NPs to cell types under extracellular compression.

Real time monitoring of drug release at specific local sites by a non-invasive imaging method is critical in patient-specific drug administration in order to avoid insufficient or excess drug dosing. In the present work, we designed a specific carrier system for such a purpose using self-decomposable SiO2 nanoparticles (NPs) with the drug being loaded in the center and Au NPs on the SiO2 NPs as the imaging agent. We discovered a correlation between the drug release from the carrier and the morphological evolution of Au NPs, which also left the carrier and changed their aggregation states along with the drug release process. This finding enabled the real time monitoring of the drug release at local sites (e.g. tumor) in a quantitative manner by recording the CT signal evolution of the Au NPs, as demonstrated in vivo using mice bearing Colo-205 xenografts. The present work provided a promising platform for non-invasive real time tracking on the localized drug release, enabling a variety of personalized therapeutic applications.

International audience; Oral candidiasis as a highly prevalent and recurrent infection in medically compromised individuals is mainly caused by the opportunistic fungal pathogen Candida albicans. This epithelial infection, if not controlled effectively, can progress to life-threatening systemic conditions and complications. The efficacy of current frontline antifungals is limited due to their poor bioavailability and systemic toxicity. As such, an efficient intervention is essential for controlling disease progression and recurrence. Herein, a theranostic nanoplatform (CD-Gu+-AmB) was developed to track the penetration of antifungals and perturb the invasion of C. albicans at oral epithelial tissues, via decorating the homemade red-emissive carbon dots (CD) with positively charged guanidine groups (Gu+) followed by conjugation with antifungal polyene (amphotericin B, AmB) in a reacting site-controllable manner. The generated CD-Gu+-AmB favorably gathered within the Candida cells and exhibited potent antifungal effects in both planktonic and biofilm forms. It selectively accumulated in the nuclei of human oral keratinocytes and exhibited undetectable toxicity to the host cells. Moreover, we reported for the first time the penetration and exfoliation profiles of CD in a three-dimensional organotypic model of human oral epithelial tissues, demonstrating that the extra- and intracellular accumulation of CD-Gu+-AmB effectively resisted the invasion of C. albicans by forming a "shielding" layer throughout the entire tissue. This study establishes a multifunctional CD-based theranostic nanoplatform functioning as a traceable and topically applied antifungal to arm oral epithelia, thereby shedding light on early intervention of mucosal candidiasis for oral and general health.

In this study, we report a new class of rhodamine-based fluorescent sensors for highly selective and sensitive detection of Pd

This work reported a facile method for fabricating multi-layered polydopamine (PDA) encapsulated AuAg@C@AuAg core/shell nanosphere with a hollow interior. During the synthetic process, the preliminary Ag@C nanosphere is easily covered by an AuAg/PDA hybrid layer through the in situ redox-oxidized polymerization to form the Ag-AuAg@C@AuAg/PDA precursor, in which the AuAg bimetallic nanocrystals are simultaneously obtained via the electrochemical substitution reaction. After etching the residue Ag core, the final AuAg@C@AuAg/PDA hybrid nanosphere is achieved and the inner AuAg shows a unique nanoframe-like nanostructure. The carbon shell plays an important role for the formation and structure evolution of the AuAg@C@AuAg/PDA, and the composition can be modulated by varying the polymerization process. Owing to the well distributed AuAg nanocrystals and inner AuAg nanoframes, the AuAg@C@AuAg/PDA shows better performance than Ag-AuAg@C@AuAg/PDA precursor in catalyzing 4-nitrophenol, and the rate constant (K) to catalyst weight ratio reaches as high as 3.63 min-1 •mg-1. As a result, this work not only offers a hybrid bi-metallic nanocatalyst with excellent performance, but also has valuable implications for compositional modulation of hollow interior multi-layered nanostructure in adsorption, drug delivery, and nanocatalysis.

Several ternary composites that are based on branched polyethyleneimine (bPEI 25 kDa, polydispersity 2.5, 0.1 or 0.2 ng), citrate-coated ultrasmall superparamagnetic iron oxide nanoparticles (citrate-NPs, 8–10 nm, 0.1, 1.0, or 2.5 µg), and reporter circular plasmid DNA pEGFP-C1 or pRL-CMV (pDNA 0.5 µg) were studied for optimization of the best composite for transfection into glioblastoma U87MG or U138MG cells. The efficiency in terms of citrate-NP and plasmid DNA gene delivery with the ternary composites could be altered by tuning the bPEI/citrate-NP ratios in the polymer composites, which were characterized by Prussian blue staining, in vitro magnetic resonance imaging as well as green fluorescence protein and luciferase expression. Among the composites prepared, 0.2 ng bPEI/0.5 μg pDNA/1.0 µg citrate-NP ternary composite possessed the best cellular uptake efficiency. Composite comprising 0.1 ng bPEI/0.5 μg pDNA/0.1 μg citrate-NP gave the optimal efficiency for the cellular uptake of the two plasmid DNAs to the nucleus. The best working bPEI concentration range should not exceed 0.2 ng/well to achieve a relatively low cytotoxicity.

Severe gum disease (periodontitis), which is one of the major global oral diseases, results from microbe-host dysbiosis and dysregulated immuno-inflammatory responses. It seriously affects oral health and general wellbeing with significant socio-economic implications. It has been well documented that natural flavonoids such as baicalin (BA) and baicalein (BE) possess potent anti-inflammatory effects. However, their intrinsic poor solubility and low bioavailability severely limit their biomedical applications. In the present study, BA and BE were encapsulated in our synthesized and amine-modified mesoporous silica nanoparticles (MSNs) (Nano-BA and Nano-BE, respectively), and their loading efficiencies and releasing profiles were investigated. Their cytotoxicity was examined on primary human gingival epithelial cells (hGECs), and the cellular uptake of Nano-BA or Nano-BE was visualized via a transmission electron microscope. Their anti-inflammatory effects were evaluated in IL-1β-treated hGECs using the cytokine array and enzyme-linked immunosorbent assay. The present study shows that the amine-modified MSNs could encapsulate BA and BE, and nano-encapsulation greatly enhances the drug delivery rate and prolongs the release of BA and BE up to 216 h. Moreover, both Nano-BA and Nano-BE could be internalized by hGECs and retained intracellularly in nanoparticle-free media for at least 24 h. Note that Nano-BE pre-treatment effectively down-regulates the IL-1β-induced expression of IL-6 and IL-8 in hGECs. In conclusion, nanoparticle-encapsulated BE exhibits notable anti-inflammatory effects through effective release and cellular internalization approaches. This study may facilitate the development of novel drug delivery systems for improving oral care.

A facile method was developed to synthesize Fe3O4/polydopamine (PDA) dual shelled microspheres with a hollow interior. Since the final product was obtained by in situ polymerization of dopamine (DA) on the surface of a hollow Fe3O4 spherical template, the average size of the hybrid microspheres was tunable by manipulating both the Fe3O4 size and the PDA shell thickness. Due to the hollow interior and the compatible surface, the Fe3O4/PDA demonstrated excellent adsorption performance for Eu(III) ion removal (151.05 mg g−1) in aqueous solution. In comparison to pristine Fe3O4 hollow spheres, the dual shelled particles exhibited a faster adsorption dynamic process and a higher adsorption capacity for Eu(III) entrapment. Simultaneously, the Fe3O4/polydopamine (PDA) also exhibits a higher adsorption capacity for Eu(III) entrapment compared with that of other magnetic materials. This method was also effective for synthesizing other kinds of PDA shell encapsulated core/shell nanoparticles.

In this work, novel mesoporous SiO 2 yolk-shell confined core-satellite Ag nanoparticles (Ag@mSiO 2 ) synthesized with a simple route were reported. Firstly, the core/shell Ag@C nanospheres whose carbon shells were doped with Ag nanoparticles, were facilely prepared by using a simple hydrothermal method. After coating with a uniform layer of hybrid SiO 2 in the presence of octadecyltrimethoxysilane (C 18 TMS), the Ag@C@h-SiO 2 composite nanospheres were obtained. The final calcination removed all the carbon and organic compound and left the yolk shell Ag@mSiO 2 nanosphere, in which an individually large Ag core and many tiny Ag nanoparticles were encapsulated within the mesoporous silica shell. The core-satellite like Ag nanoparticles exhibited excellent catalytic activity in RhB reduction. Benefited from the m -SiO 2 shell with a uniform pore size of 3.5 nm, the bi-mode Ag nanoparticles were very stable, thus the activity of Ag@mSiO 2 could keep as high as 92% after five cycles.

Biomedical applications of non-spherical nanoparticles such as photothermal therapy and molecular imaging require their efficient intracellular delivery, yet reported details on their interactions with the cell remain inconsistent. Here, the effects of nanoparticle geometry and receptor targeting on the cellular uptake and intracellular trafficking are systematically explored by using C166 (mouse endothelial) cells and gold nanoparticles of four different aspect ratios (ARs) from 1 to 7. When coated with poly(ethylene glycol) strands, the cellular uptake of untargeted nanoparticles monotonically decreases with AR. Next, gold nanoparticles are functionalized with DNA oligonucleotides to target Class A scavenger receptors expressed by C166 cells. Intriguingly, cellular uptake is maximized at a particular AR: shorter nanorods (AR = 2) enter C166 cells more than nanospheres (AR = 1) and longer nanorods (AR = 4 or 7). Strikingly, long targeted nanorods align to the cell membrane in a near-parallel manner followed by rotating by ≈90° to enter the cell via a caveolae-mediated pathway. Upon cellular entry, targeted nanorods of all ARs predominantly traffic to the late endosome without progressing to the lysosome. The studies yield important materials design rules for drug delivery carriers based on targeted, anisotropic nanoparticles.

In this study, we report a new class of rhodamine-based fluorescent sensors for highly selective and sensitive detection of Pd2+ ions in aqueous medium. A rhodamine-based palladium sensor RPS and a coumarin-rhodamine Forster resonance energy transfer (FRET)-pair based palladium sensor FPS were synthesized with the designed podand ligand for Pd2+ ion recognition. They showed both colorimetric change and fluorometric change in the presence of Pd2+ ion due to the opening of their spirolactam rings. Both chemosensors are highly selective to Pd2+ over the other 24 different metal ions and they are selective to palladium species in +2 oxidation state, RPS showed a 70-fold fluorescent turn-on while FPS showed a 1.75-fold ratiometric change at I599/I470. Furthermore, RPS showed low cell cytotoxicity and it was successfully used to image Pd2+ in BEAS-2B lung epithelial cells. © 2019 Elsevier Science. All rights reserved.

Many nanoparticle-based carriers to atherosclerotic plaques contain peptides, lipoproteins, and sugars, yet the application of DNA-based nanostructures for targeting plaques remains infrequent. In this work, we demonstrate that DNA-coated superparamagnetic iron oxide nanoparticles (DNA-SPIONs), prepared by attaching DNA oligonucleotides to poly(ethylene glycol)-coated SPIONs (PEG-SPIONs), effectively accumulate in the macrophages of atherosclerotic plaques following an intravenous injection into apolipoprotein E knockout (ApoE–/–) mice. DNA-SPIONs enter RAW 264.7 macrophages faster and more abundantly than PEG-SPIONs. DNA-SPIONs mostly enter RAW 264.7 cells by engaging Class A scavenger receptors (SR-A) and lipid rafts and traffic inside the cell along the endolysosomal pathway. ABS-SPIONs, nanoparticles with a similarly polyanionic surface charge as DNA-SPIONs but bearing abasic oligonucleotides also effectively bind to SR-A and enter RAW 264.7 cells. Near-infrared fluorescence imaging reveals evident lo...

This work reports a facile one-step method for the fabricating Fe3O4@Au/polydopamine sandwich-like core-shell nanostructure, in which the Au/polydopamine (Au/PDA) hybrid shell is obtained via an in situ redox-oxidation polymerization between the HAuCl4 and dopamine. The content of Au nanocrystals, shell thickness, and particle sizes are tunable by varying the experimental parameters. Intriguingly, this general method can be applied for different functional nanostructures such as the β-FeOOH@Au/PDA, SiO2@Au/PDA, and CNT@Au/PDA nanocomposites. A possible formation mechanism is proposed and it is found that the surface interaction plays a key role in determining the final nanostructure. The as-prepared Fe3O4@Au/PDA exhibited eminent catalytic activity on the reduction of 4-nitrophenol. Since the external PDA shell prevents the Au nanocrystals from leaching during the reduction, the cycling activity has been maintained as high as 95% after seven times of catalytic reaction.

A facile one-step method was developed to synthesize core–shell structured SiO2@polydopamine (PDA) nanospheres. During the synthesis, a PDA shell was simultaneously coated on the SiO2 nanospheres to form the core–shell nanostructure. The PDA shell thickness was tunable by varying the concentration of the starting dopamine precursor. After dispersing the core–shell nanospheres into poly(ethylene glycol) 200 (PEG200), a SiO2@PDA based shear thickening fluid (STF) was obtained. In comparison to pristine SiO2, the SiO2@PDA based STF presented better ST effects and its maximum viscosity could reach as high as 194.6 Pa s. A possible enhancement mechanism was proposed in order to investigate the structural dependence of the ST effect. This high performance SiO2@PDA based STF could be widely applied in body armor and other safe-guarding areas.

The fluorescent carbon dot (C-dot) is a new class of carbon nanomaterials. It has a discrete or quasispherical structure, typically measures less than 10 nm and contains sp(2)/sp(3) carbon, oxygen/nitrogen-based groups and surface-modified functional groups. Compared with semiconductor quantum dots (QDs), C-dots offer much lower toxicity and a better biocompatibility profile. Their other favorable features include easy and inexpensive synthesis and surface modification potential. C-dots can be morphologically classified into graphene-based quantum dots (GQDs) and amorphous carbon nanodots (ACNDs). Numerous methods have been developed to synthesize C-dots, and are mainly divided into 'top-down' and 'bottom-up' routes. In the top-down route, C-dots (mostly GQDs) is derived from the separation of large carbon precursors. The 'bottom-up' method primarily involves the dehydration, polymerization and carbonization of small molecules to form the GQDs and ACNDs through thermal/hydrothermal synthesis, microwave irradiation, and solution chemistry. Potential applications of C-dots have been explored in a number of cellular and in-vivo imaging approaches. However, some difficulties remain, including limited penetration depth and poorly controlled in-vivo pharmacokinetics, which depends on multiple factors such as the morphology, physiochemical properties, surface chemistry and formulation of C-dots. The exact mechanism of in-vivo biodistribution, cellular uptake and long-term toxicological effect of C-dots still need to be elucidated. An integrated multi-disciplinary approach involving chemists, pharmacologists, toxicologists, clinicians, and regulatory bodies at the early stage is essential to enable the clinical application of C-dots.