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One of the biggest challenges of the protein delivery system is to realize stable and high protein encapsulation efficiency in blood circulation and rapid release of protein in the targeted tumor cells. To overcome these hurdles, we fabricated enzyme-responsive photo-cross-linked nanogels (EPNGs) through UV-triggered chemical cross-linking of cinnamyloxy groups in the side chain of PEGylation hyaluronic acid (HA) for CD44-targeted transport of cytochrome c (CC). The EPNGs showed high loading efficiency and excellent stability in different biological media. Notably, CC leakage effectively suppressed under physiological conditions but accelerated release in the presence of hyaluronidase, an overexpressed enzyme in tumor cells. Moreover, thiazolylblue tetrazolium bromide (MTT) results indicated that the vacant EPNGs showed excellent nontoxicity, while CC-loaded EPNGs exhibited higher killing efficiency to CD44-positive A549 cells than to CD44-negative HepG2 cells and free CC. Confocal images confirmed that CC-loaded EPNGs could effectively be internalized by CD44-mediated endocytosis pathway and rapidly escape from the endo/lysosomal compartment. Human lung tumor-bearing mice imaging assays further revealed that CC-loaded EPNGs actively target tumor locations. Remarkably, CC-loaded EPNGs also exhibited enhanced antitumor activity with negligible systemic toxicity. These results implied that these EPNGs have appeared as stable and promising nanocarriers for tumor-targeting protein delivery.

Glyconanomaterials have shown high potential in applications including bioanalysis and nanomedicine. Here, a quantitative analytical technique, based on isothermal titration calorimetry, was developed to characterize the interactions between glyconanoparticles and lectins. By titrating lectins into the glyconanoparticte solution, the apparent dissociation constant, thermodynamic parameters, and the number of binding sites were derived simultaneously. For the glyconanoparticles-lectin binding pairs investigated, a 3-S order of magnitude affinity enhancement over the free tigand-lectin interactions was observed which can be attributed to the multivalent ligand presentation on the nanoparticles. The impact of ligand density was also studied, and results showed that the affinity increased with the number of glycans on the nanopartide. [ABSTRACT FROM AUTHOR]

We report a new type of microarray, based on glyconanoparticles (GNPs), to study glycan—lectin interactions. GNPs, synthesized by conjugating carbohydrate ligands on silica nanoparticles, were printed on a photoactive surface followed by covalent immobilization by light activation. The GNP microarrays could be probed by lectins labeled with fluorescein as well as fluorescein-doped silica nanoparticles (FSNPs). Results showed that FSNP as the label enhanced the signals for the higher affinity ligands than the lower ones. [ABSTRACT FROM AUTHOR]

We report a novel core-shell-structured ternary nanocube of MnZn ferrite synthesized by controlling the reaction temperature and composition in the absence of conventionally used reducing agents. The highly monodispersed core-shell structure consists of an Fe3O4 core and an MnZn Ferrite shell. The observation of a Moiré pattern indicates that the core and the shell are two highly crystalline materials with slightly different lattice constants that are rotated relative to each other by a small angle. The ternary core-shell nanocubes display magnetic properties regulated by a combination of the core-shell composition and exhibit an increased coercivity and field-cooled/zero-field-cooled characteristics drastically different from those of regular MnZn ferrite nanoparticles. The ability to engineer the spatial nanostructures of ternary magnetic nanoparticles in terms of shape and composition offers atomic-level versatility in fine-tuning the nanoscale magnetic properties. [ABSTRACT FROM AUTHOR]

The silica/polymer hybrid hollow nanoparticles with channels and gatekeepers were successfully fabricated with a facile strategy by using thermoresponsive complex micelles of poly(ethylene glycol)-b-poly(N-isopropylacrylamide) (PEG-b-PNIPAM) and poly(N-isopropylacrylamide)-b-poly(4-vinylpyridine) (PNIPAM-b-P4VP) as the template. In aqueous solution, the complex micelles (PEG-b-PNIPAM/PNIPAM-b-P4VP) formed with the PNIPAM block as the core and the PEG/P4VP blocks as the mixed shell at 45 °C and pH 4.0. After shell cross-linking by 1,2-bis(2-iodoethoxyl)ethane (BIEE), tetraethylorthosilicate (TEOS) selectively well-deposited on the P4VP block and processed the sol−gel reaction. When the temperature was decreased to 4 °C, the PNIPAM block became swollen and further soluble, and the PEG-b-PNIPAM block copolymer escaped from the hybrid nanoparticles as a result of swelled PNIPAM and weak interaction between PEG and silica at pH 4.0. Therefore, the hybrid hollow silica nanoparticles with inner thermoresponsive PNIPAM as gatekeepers and channels in the silica shell were successfully obtained, which could be used for switchable controlled drug release. In the system, the complex micelles, as a template, could avoid the formation of larger aggregates during the preparation of the hybrid hollow silica nanoparticles. The thermoresponsive core (PNIPAM) could conveniently control the hollow space through the stimuli-responsive phase transition instead of calcination or chemical etching. In the meantime, the channel in the hybrid silica shell could be achieved because of the escape of PEG chains from the hybrid nanoparticles. [ABSTRACT FROM AUTHOR]

Glyconanomaterials, nanomaterials canying multiple carbohydrate ligands, provide an excellent platform for sensitive protein recognition. Using nanomaterials as the scaffold, multivalent interactions between glycan ligands and pmteins have been demonstrated. However, the quantitative analysis of the binding affinity of these glyconanomaterials has been lacking. In this Article, we report a new method to measure the binding affinity of glyconanoparticle (GNP)-protein interactions based on a fluorescent competition binding assay, which yielded the apparent dissociation constant (Kd) of GNPs with the interacting protein. Au nanoparticles conjugated with underivatized mono-, oligo-, and polysaccharides were synthesized using our recently developed photo coupling chemistry. The affinities of these GNPs with lectins were measured and were several orders of magnitude higher than the corresponding free ligands with lectins. The effect of ligand display on the binding affinity of GNPs was, furthermore, studied where GNPs of varying linker type, spacer length, ligand density, and nanoparticle size were prepared and Kd values determined. The long spacer linker containing hydrocathon and ethylene oxide units gave the highest binding affinity as well as assay sensitivity. The binding affinity increased with ligand density in general, showing a drastic increase in affinity at low ligand density. In addition, the affinity enhancement was more pronounced on smaller NPs than the larger ones. These results not only demonstrate that the binding affinity of GNPs is highly influenced by how the ligands are presented on the nanoparticles but also pave the way for tailor-made glyconanomaterials with tunable affinity by way of ligand display. [ABSTRACT FROM AUTHOR]

A microporous tube-in-tube microchannel reactor (MTMCR) was successfully adopted to prepare hydroxyapatite (HAP) nanoparticles. The rodlike HAP nanoparticles with a mean size of 58 nm, a specific surface area of 49.32 m2/g, and a narrow size distribution were obtained in an MTMCR under a high throughput of 3 L/min. The mean particle size sharply decreased with increasing the continuous phase flow rate, while first decreased and subsequently increased with increasing the dispersed phase flow rate and the reactant concentration. The extension of the mixing distance led to the initial rapid and following slight decrease of the mean particle size. The size of HAP nanoparticles was also strongly dependent on the micropore size on the surface of inner tube. Small micropore size was beneficial for producing small particles. For comparison, HAP nanoparticles were also prepared in a stirred tank reactor (STR) and a T-junction microchannel reactor (TMCR), clearly exhibiting the advantages of the MTMCR over the STR and TMCR due to the achievement of uniformly smaller HAP nanoparticles and a high throughput for industrial production. [ABSTRACT FROM AUTHOR]

High-density aligned n-type silicon nanowire (SiNW) arrays decorated with discrete 5−10 nm platinum nanoparticles (PtNPs) have been fabricated by aqueous electroless Si etching followed by an electroless platinum deposition process. Coating of PtNPs on SiNW sidewalls yielded a substantial enhancement in photoconversion efficiency and an apparent energy conversion efficiency of up to 8.14% for the PtNP-decorated SiNW-based photoelectrochemical solar cell using a liquid electrolyte containing Br−/Br2redox couple. The results demonstrate PtNP-decorated SiNWs to be a promising hybrid system for solar energy conversion. [ABSTRACT FROM AUTHOR]

Microchannel reactors are a rapidly emerging and promising technology field for their enhanced mass transfer and excellent heat exchange induced by dimensional effects. A method, the liquid antisolvent precipitation (LASP) process in a microchannel reactor (MCR), is proposed here to directly synthesize danazol nanoparticles without additives. The mean particle size decreased from 55 m to 364 nm, and the specific surface area increased from 0.66 to 14.37 m2/g after the LASP process in MCR. The mean particle size can be facilely controlled by regulating the parameter of the MCR setup. The chemical composition and physical characteristics of the as-prepared danazol nanoparticles were demonstrated to be unchanged after processing according to FT-IR and XRD analyses. Correspondingly, the dissolution rate of the nanoparticles within 5 min was enhanced from 35% to 100% compared to the raw danazol particles. Combined with the controlled LASP method, MCR exhibits great potential for preparation of hydrophobic drugs with uniform particle size distribution in the nanometer range. [ABSTRACT FROM AUTHOR]

Carbohydrate-functionalized gold nanoparticles were employed to differentiate plant-legume lectins using a statistical analysis method of linear discriminant analysis (LDA). Various carbohydrates were conjugated on gold nanoparticles, and the resulting glyconanoparticles were treated with lectins. Changes in the localized surface plasmon resonance of the glyconanoparticles upon lectin binding were recorded, and the data were subjected to LDA. Results showed that the glyconanoparticles successfully differentiated all lectins. [ABSTRACT FROM AUTHOR]

The purpose of this study was to prepare megestrol acetate (MA) nanoparticles via a liquid precipitation technique. Several experimental parameters, such as the stabilizer combination, the volume ratio of antisolvent to drug solution, the temperature, the stirring speed, and the drying method were investigated. The as-prepared MA particles had a mean size of 208 nm, and 90% of the particles were distributed in the range of 100−300 nm, whereas the raw MA had a mean particle size of about 3.02 μm, ranging widely from 0.2 μm to 30 μm. X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) analysis indicated that MA nanoparticles exhibited decreased crystallinity and unchanged chemical group structure after precipitation. The freeze-dried MA nanoparticles exhibited improved wettability as demonstrated by the contact angle measurement result proving that particles were covered by a hydrophilic layer. In dissolution rate tests, the nanoparticles achieved 100% drug dissolution within 5 min, while the raw MA did not dissolve completely after 120 min, suggesting that the dissolution property of MA nanoparticles was significantly enhanced. [ABSTRACT FROM AUTHOR]

Toenhance the solubility and dissolution rate, and thus potentiallyimprove the oral bioavailability of cefixime (CFX), amorphous CFXnanoparticles were prepared via high-gravity antisolvent precipitation(HGAP) without the aid of any pharmaceutical additives in a rotatingpacked bed (RPB). The effects of operating variables on particle sizeand distribution were investigated. Compared to raw CFX, the meansize of prepared nanoparticles decreased greatly from about 2.1 μmto 57 nm, and the saturation solubility increased tremendously from0.289 to 0.951 mg/mL. CFX nanoparticles showed good stability andwere capable of generating a maximum supersaturation level, reachingup to ∼22.8 times of raw CFX’s saturation solubility.Further, CFX nanoparticles achieved 100% drug dissolution within 2min, while the raw drug did not dissolve completely after 45 min,suggesting that the solubility and dissolution properties of CFX nanoparticleswere significantly improved. Since the drug recovery ratio achieved99.9%, and the production capacity of lab-scale RPB with a continuousoperation reached 1.8 kg/h, the HGAP method might offer a generaland facile platform for mass production of CFX nanoparticles. [ABSTRACT FROM AUTHOR]

Local microenvironment pH sensing is one of the key parameters for the understanding of many biological processes. As a noninvasive and high sensitive technique, surface-enhanced Raman spectroscopy (SERS) has attracted considerable interest in the detection of the local pH of live cells. We herein develop a facile way to prepare Au-(4-MPy)-BSA (AMB) pH nanosensor. The 4-MPy (4-mercaptopyridine) was used as the pH sensing molecule. The modification of the nanoparticles with BSA not only provides a high sensitive response to pH changes ranging from pH 4.0 to 9.0 but also exhibits a high sensitivity and good biocompatibility, stability, and reliability in various solutions (including the solutions of high ionic strength or with complex composition such as the cell culture medium), both in the aggregation state or after long-term storage. The AMB pH nanosensor shows great advantages for reliable intracellular pH analysis and has been successfully used to monitor the pH distribution of live cells and can address the grand challenges in SERS-based pH sensing for practical biological applications. [ABSTRACT FROM AUTHOR]

Cefuroxime axetil (CFA) drug nanoparticles were prepared by liquid antisolvent precipitation in a microchannel system with a T-shaped junction formed by a main microchannel and a branch. Isopropyl ether as the antisolvent (high flow rate) was usually passed through the main microchannel, and CFA acetone solution as the solvent (low flow rate) was injected into the branch simultaneously. The solvent diffused from the CFA acetone solution stream into the antisolvent phase, which resulted in the supersaturation of CFA and thus led to the rapid precipitation of CFA nanoparticles. The change of the injection phase from CFA acetone solution to isopropyl ether was found to have a significant effect on the formation of CFA nanoparticles owing to the different contact behavior. The morphology and size of CFA nanoparticles were characterized by scanning electronic microscopy (SEM) and particle size distribution (PSD) measurements by laser diffractometry. Furthermore, the effects of CFA acetone solution velocity, antisolvent velocity, overall velocity, and CFA concentration on the particle size and size distribution were experimentally investigated. The as-prepared CFA nanoparticles were amorphous and exhibited a higher dissolution rate than raw CFA. This work suggests that microfluidics might find wide applications in the development and optimization of drug nanoparticles in the newly emerging field of nanomedicine. [ABSTRACT FROM AUTHOR]

The excellent shock-absorbing performance of WS2 and MoS2 nanoparticles with inorganic fullerene-like structures (lFs) under very high shock wave pressures of 25 GPa is described. The combined techniques of X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, thermal analysis, and transmission electron microscopy have been used to evaluate the diverse, intriguing features of shock recovered IFs, of interest for their tribological applications, thereby allowing improved understanding of their antishock behavior and structure-property relationships. Two possible failure mechanisms are proposed and discussed. The supershock-absorbing ability of the IF-WS2 enables them to survive pressures up to 25 GPa accompanied with concurrent temperatures of up to 1000 °C without any significant structural degradation or phase change making them probably the strongest cage molecules now known. [ABSTRACT FROM AUTHOR]