Magnetic mesoporous nanomaterials with AIE properties for selective detection and removal of CN- from water under magnetic conditions.

We have prepared a type of magnetic mesoporous nanomaterial with aggregation-induced emission properties (Fe3O4@mSiO2@TPA@BA, hence abbr. FSTB) to detect and remove cyanide ions (CN-) under magnetic conditions. FSTB has a large specific surface area and improved fluorescence performance to identify CN-, and its superparamagnetic behavior plays an important role in removing CN-. The magnetic sensor FSTB shows excellent selectivity and anti-interference for the detection of CN- in aqueous solutions. It is obvious from the equation LOD = 3δ/S that the limit of detection (LOD) of FSTB for CN- is significantly lower than the permissible level of CN- in drinkable water recommended by the World Health Organization. Therefore, the magnetic sensor FSTB has a wide range of applications for detecting and removing harmful CN-.

Correction: Preparation of electrospray ALG/PDA-PVP nanocomposites and their application in cancer therapy.

Correction for 'Preparation of electrospray ALG/PDA-PVP nanocomposites and their application in cancer therapy' by Yangjie Xu et al., Soft Matter, 2020, 16, 132-141.

Preparation of electrospray ALG/PDA-PVP nanocomposites and their application in cancer therapy.

In this study, sodium alginate (ALG)/poly dopamine (PDA)-polyvinylpyrrolidone (PVP) nanocomposites was synthesized via a one-step electrostatic spraying method. The spinning solution of ALG and dopamine was electrostatically sprayed into an alkaline solution of PVP, calcium chloride and tris buffer (pH = 8.5), in which the gelation of ALG and the polymerization of dopamine could be simultaneously triggered. PDA hence produced possesses a high photothermal conversion efficiency, while the PVP that was facilely conjugated onto the surface of nanocomposites improves the colloidal stability and compatibility of the material. Moreover, the ALG renders the nanocomposite excellent drug (doxorubicine, DOX) loading capacity. Promisingly, the temperature increment during the PTT process could promote the DOX release, thus enhancing its therapeutic effect. The in vitro/in vivo biosafety and tumor treatment experiments further corroborate that the ALG/PDA-PVP nanocomposites have remarkable biocompatibility and synergism for tumor hyperthermia and chemotherapy. Consequently, such a one-step electrospray strategy provides a new way for designing nanomaterials and is expected to significantly promote the development of organic photothermal therapeutic agents with excellent bio-compatibility.

Preparation of silica microspheres with a broad pore size distribution and their use as the support for a coated cellulose derivative chiral stationary phase.

A templating strategy using crosslinked and functionalized polymeric beads to synthesize silica microspheres with a broad pore size distribution has been developed. The polymer/silica hybrid microspheres were prepared by utilizing the combination of a templating weak cation exchange resin, a structure-directing agent N-trimethoxysilylpropyl-N,N,N-trimethylammonium chloride, and a silica precursor tetraethyl orthosilicate. The silica microspheres were then obtained after calcinating the hybrid microspheres. The as-prepared materials were characterized by scanning electron microscopy, mercury intrusion porosimeter, and thermal gravimetric analysis. The results showed that the starting templating beads were about 5 µm in diameter and the formed silica microspheres were less than 3 µm with a pore size range of 10-150 nm, some pores were even extended to beyond 250 nm. It was demonstrated that cellulose tris(3,5-dimethylphenylcarbamate) was readily coated onto the surface of the as-synthesized silica microspheres without any additional surface pretreatment. The coated silica microspheres were uniformly dispersed even with high loading of the chiral stationary phase, which exhibited high resolution chiral separations in high-performance liquid chromatography.

Design of electrospun nanofibrous mats for osteogenic differentiation of mesenchymal stem cells.

The clinical translation potential of mesenchymal stem cells (MSCs) in regenerative medicine has been greatly exploited. With the merits of high surface area to volume ratio, facile control of components, well retained topography, and the capacity to mimic the native extracellular matrix (ECM), nanofibers have received a great deal of attention as bone tissue engineering scaffolds. Electrospinning has been considered as an efficient approach for scale-up fabrication of nanofibrous materials. Electrospun nanofibers are capable of stimulating cell-matrix interaction to form a cell niche, directing cellular behavior, and promoting the MSCs adhesion and proliferation. In this review, we give a comprehensive literature survey on the mechanisms of electrospun nanofibers in supporting the MSCs differentiation. Specifically, the influences of biological and physical osteogenic inductive cues on the MSCs osteogenic differentiation are reviewed. Along with the significant advances in the field, current research challenges and future perspectives are also discussed.

Dendritic Mesoporous Silica Nanospheres Synthesized by a Novel Dual-Templating Micelle System for the Preparation of Functional Nanomaterials.

Highly monodisperse, dendritic, and functionalized mesoporous silica nanospheres (MSNs) with sub-200 nm size were synthesized in a one-pot sol-gel reaction, by a dual-templating micelle system consisting of a partially fluorinated short-chain anionic fluorocarbon surfactant and cetyltrimethylammonium bromide. This kind of anionic fluorocarbon surfactant works simultaneously as a swelling agent to enlarge the pore of the MSNs, an ion-pair agent to the structure-directing silane in the preparation of amine-functionalized MSNs, and a surface tension reducing agent to make the system thermodynamically more stable for producing more uniform MSNs. The particle size and the morphology of the resultant MSNs can be fine-tuned by changing the amount of the fluorocarbon surfactant added and the ratio of the functional group containing organosilane to tetraethoxysilane. Subsequently, the as-prepared MSNs were used as base materials for the preparation of drug delivery nanomaterials through the surface grafting of a pH-sensitive drug-conjugated polymer and fluorescent nanomaterials through the embedding of europium(III) complex or the immobilization of large molecule fluorescein isothiocyanate-bovine serum albumin.

Synthesis of cellulose-2,3-bis(3,5-dimethylphenylcarbamate) in an ionic liquid and its chiral separation efficiency as stationary phase.

A chiral selector of cellulose-2,3-bis(3,5-dimethylphenylcarbamate) (CBDMPC) was synthesized by reacting 3,5-dimethylphenyl isocyanate with microcrystalline cellulose dissolved in an ionic liquid of 1-allyl-3-methyl-imidazolium chloride (AMIMCl). The obtained chiral selector was effectively characterized by infrared spectroscopy, elemental analysis and 1H NMR. The selector was reacted with 3-aminopropylsilanized silica gel and the CBDMPC bonded chiral stationary phase (CSP) was obtained. Chromatographic evaluation of the prepared CSPs was conducted by high performance liquid chromatographic (HPLC) and baseline separation of three typical fungicides including hexaconazole, metalaxyl and myclobutanil was achieved using n-hexane/isopropanol as the mobile phase with a flow rate 1.0 mL/min. Experimental results also showed that AMIMCl could be recycled easily and reused in the preparation of CSPs as an effective reaction media.

A novel method to prepare monolithic molecular imprinted polymer fiber for solid-phase microextraction by microwave irradiation.

In this paper, a new approach to prepare monolithic molecularly imprinted polymer (MIP) fibers for solid-phase microextraction is proposed with the help of microwave irradiation. Imprinting polymerization was carried out within silica capillaries in 4.5 min, using dimethyl phthalate (DMP) as a template molecular, α-methacrylic acid as a functional monomer and ethylene dimethacrylate as a crosslinker, acetonitrile as the porogenic solvent. The synthesis was optimized by varying the ratio of template/monomer and different volume of porogen. The resulted MIP fibers were obtained after silica being etched away with a controlled length of 1 cm, and subsequently characterized by SEM. In order to increase the selective extraction of DMP, factors affecting the extraction including extraction time, salt concentration, desorption time, and desorption solvents were investigated for solid-phase microextraction procedures in detail. The selectivity coefficients, defined as the extraction amount ratio of MIP to its nonimprinting fiber, were 5.6, 2.6, and 1.4 for DMP and its counterpart including dibutyl phthalate and di-n-octylo-phthalate, respectively. The resulted fibers were also applied to detect DMP, dibutyl phthalate, and di-n-octylo-phthalate in bottled beverage samples coupled to HPLC and resulted in relative recoveries of up to 73.8-98.5%, respectively.

Hierarchical Core-Shell Fe3O4@mSiO2@Chitosan Nanoparticles for pH-Responsive Drug Delivery.

Hierarchical nanoparticles are of great interest because they possess unique physicochemical properties and multiple functionalities, providing a wealth of possibilities for various applications. In this work, we have developed a well-designed method to prepare hierarchical magnetic nanoparticles Fe3O4@mSiO2@CS by integrating a solvothermal method for synthesizing the Fe3O4 core, a dualtemplating micelle system for preparing a layer of mesoporous silica (mSiO2) shell, and a silane coupling method via γ-glycidoxypropyltrimethoxysilane for binding a chitosan (CS) layer on the silica surface. The porous hierarchical nanoparticles were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), dynamic light scattering nanoparticle size analyzer, and specific surface area and pore size analyzer. The loading capacity and the release behavior of the as-prepared nanoparticles for doxorubicin hydrochloride were studied, and it was found that the drug release rate was faster at pH 6.0 than at pH 7.4, revealing the pH-responsive property of the nanoparticles.

Preparation of Bi-based hydrogel for multi-modal tumor therapy.

Radiotherapy (RT) is becoming a pervasive therapeutic pattern in clinical cancer therapy. However, the hypoxic microenvironment of tumors has a strong resistance to radiotherapy and could lead to a potential recurrence and metastasis after the treatment. Therefore, the use of synergistic strategies for improving and supplementing the RT efficiency is important. Herein, a novel Bi2S3/alginate (ALG) hydrogel containing tirapazamine (TPZ) was designed for the effective suppression of tumor recurrence, by introducing Bi3+ into the ALG, Na2S and TPZ solution. In this formulation, Bi3+ was used to crosslink with the ALG to form the hydrogel and react with S2- to simultaneously form Bi2S3 nanoparticles in the hydrogel matrix. The resulting Bi2S3 nanoparticles not only exhibit the superb radiosensitization effect to boost the effective eradication of tumors during RT but also manifest an excellent photothermal transforming performance for tumor hyperthermia and computed tomography (CT) imaging capacity for tumor monitoring. Furthermore, the RT caused hypoxia could activate the reductive prodrug TPZ and enhance its therapeutic efficiency. The reported hydrogel system provides an efficient and safe therapeutic strategy for current local tumor therapy.

An albumin-conjugated peptide exhibits potent anti-HIV activity and long in vivo half-life.

The clinical application of conventional peptide drugs often is limited by their short in vivo half-life and potential immunogenicity. Frequent injection presents challenges to the treatment of chronic diseases, such as HIV infection. We chemically modified a peptide HIV fusion inhibitor with 3-maleimidopropionic acid (MPA), which allows rapid and irreversible conjugation with serum albumin at a 1:1 molar ratio. FB006M, with an MPA modification at the 13th amino acid, rapidly formed conjugate with albumin upon intravenous injection, and it exhibited a remarkably extended in vivo half-life. The albumin conjugate of FB006M displayed potent inhibitory activity against a number of laboratory and clinical isolates of HIV-1 in vitro and in vivo. No immunogenicity or antibody formation was detected after repeated dosing. The clinical application of FB006M may decrease the cost of treatment and improve treatment compliance and patient quality of life.

[Preparation of a versatile polyethylene glycol-bonded stationary phase based on silica monolith particles and its application in multi-modal separation in high performance liquid chromatography].

Silica monolith particles with sizes of 2-5 µm and pore sizes of 20-60 nm were obtained by grinding, flotation, pseudomorphic transformation, and hydrothermal treatment of the silica monolith prepared by the sol-gel method. The pseudomorphic transformation was performed with a dual micellar templating system consisting of Capstone FS-66, a partially fluorinated anion surfactant, and cetyltrimethylammonium bromide (CTAB), a commonly used cation surfactant. Hydrothermal treatment with a sodium carbonate solution was adopted to further expand the pore size. Scanning electron microscopy (SEM) images and N2 adsorption-desorption isotherm measurement results of the silica monolith particles before and after the treatments clearly demonstrated the changes in morphology caused by these treatments. Afterward, a long-chain polyethylene glycol (PEG) containing silane was bonded on the surface of the as-prepared particles, and the resulting products were characterized by elemental analysis and FT-IR spectroscopy analysis, and evaluated by high performance liquid chromatography (HPLC). Elemental analysis and thermogravimetric analysis (TGA) of the bonded stationary phase revealed that the bonding amount of PEG on the silica surface is about 8%. It has been shown that silica monolith particles can be treated and modified for the separation of proteins in size exclusion chromatography mode. It is also demonstrated that the bonded stationary phase can be used for the separation of ribonuclease A and lysozyme in hydrophobic interaction chromatography mode, and for the separation of highly polar compounds (picolinic acid, levodopa, melamine, and catechol) in hydrophilic interaction chromatography mode. The results indicate the versatility of the PEG-bonded stationary phase and its promising application to multi-modal separation in HPLC.

Ni-Catalyzed Denitrogenative Cross-Coupling of Benzotriazinones and Cyclopropanols: An Easy Access to Functionalized ß-Aryl Ketones.

A novel Ni-catalyzed denitrogenative cross-coupling between benzotriazinones and cyclopropanols is reported herein. This neoteric reactivity allows for the convenient synthesis of ß-(o-amido)aryl ketones from readily available starting materials with good yields (up to 93%) and general substrate scope.

Chiral separations with crosslinked cellulose derivatives attached onto hybrid silica monolith particles via the thiol-ene click reaction.

A hybrid silica monolith containing vinyl groups was synthesized by a sol-gel method, and then ground and treated, yielding silica particles with a 3-5 µm particle size and a 10-20 nm pore size. Cellulose derivatives containing 3,5-dimethylphenylcarbamate groups and methacrylate groups regioselectively were then immobilized onto the surface of the above particles by the thiol-ene click reaction using an alkanedithiol as the crosslinking agent, thus forming a solvent-resisting crosslinked network structure attached onto the surface of the particles. The immobilization degree was more than 80%, and the back pressure of the chiral stationary phase (CSP) packed column was relatively low and was maintained at around 3.0 MPa. The as-prepared CSPs were shown to be able to effectively separate various enantiomers with different mobile phases.

Recent Advances in the Synthesis, Surface Modifications and Applications of Core-Shell Magnetic Mesoporous Silica Nanospheres.

The hierarchically structured core-shell magnetic mesoporous silica nanospheres (Mag-MSNs) have attracted extensive attention, particularly in studies involving reliable preparations and diverse applications of the multifunctional nanomaterials in multi-disciplinary fields. Intriguingly, Mag-MSNs have been prepared with well-designed synthesis strategies and used as adsorbent materials, biomedicines, and in proteomics and catalysis due to their excellent magnetic responsiveness, enormous specific surface area and readiness for surface modifications. Through a carefully designed surface modification of Mag-MSNs, the performance and application prospects of the material are greatly improved. Typically, the introduction of various molecular matrices into the shell of Mag-MSNs facilitates the combination of surface modifications and magnetic separation technology. So far, as sustainable chemistry is concerned, it is important to recover the functionalized core-shell Mag-MSNs after the reaction and reuse them without losing activity. In this review, the design conceptions and the construction of core-shell Mag-MSNs are discussed. Furthermore, various surface modification approaches of core-shell Mag-MSNs are summarized, and recent applications of these functionalized nanomaterials in the fields of biomedicine, catalysis, proteomics and wastewater treatment are exemplified.

Magnetic Silica Nanosystems With NIR-Responsive and Redox Reaction Capacity for Drug Delivery and Tumor Therapy.

In recent years, more and more researches have focused on tumor photothermal therapy and chemodynamic therapy. In this study, we prepared a multifunctional nanomaterial with potential applications in the above area. The Fe3O4 nanoparticles were synthesized with suitable size and uniformity and then coated with mesoporous silica and polydopamine. The unique core-shell structure not only improves the drug loading of the magnetic nanomaterials, but also produces high photothermal conversion efficiency. Furthermore, the reducibility of polydopamine was found to be able to reduce Fe3+ to Fe2+ and thus promote the production of hydroxyl radicals that can kill the tumor cells based on the Fenton reaction. The magnetic nanomaterials are capable of simultaneously combining photothermal and chemodynamic therapy and permit the efficient treatment for tumors in the future.

Integration of Fe3O4 with Bi2S3 for Multi-Modality Tumor Theranostics.

The combination of reactive oxygen species (ROS)-induced chemodynamic therapy (CDT) and photothermal therapy (PTT) holds a promising application prospect for their superb anticancer efficiency. Herein, we created a novel Fe3O4@polydopamine (PDA)@bovine serum albumin (BSA)-Bi2S3 composite as a theranostic agent, by chemically linking the Fe3O4@PDA with BSA-Bi2S3 via the amidation between the carboxyl groups of BSA and the amino groups of PDA. In this formulation, the Fe3O4 NPs could not only work as a mimetic peroxidase to trigger Fenton reactions of the innate H2O2 in the tumor and generate highly cytotoxic hydroxyl radicals (•OH) to induce tumor apoptosis but also serve as the magnetic resonance imaging (MRI) contrast agent to afford the precise cancer diagnosis. Meanwhile, the PDA could prevent the oxidization of Fe3O4, thus supporting the long-term Fenton reactions and the tumor apoptosis in the tumor. The Bi2S3 component exhibits excellent photothermal transducing performance and computed tomography (CT) imaging capacity. In addition, the PDA and Bi2S3 endow the Fe3O4@PDA@BSA-Bi2S3 composite with an excellent photothermal transforming ability which could lead to tumor hyperthermia. All of these merits play the synergism with the tumor microenvironment and qualify the Fe3O4@PDA@BSA-Bi2S3 NPs for a competent agent in the MRI/CT-monitored enhanced PTT/CDT synergistic therapy. Findings in this research will evoke new interests in future cancer therapeutic strategies based on biocompatible nanomaterials.

Synthesis of a Clay-Based Nanoagent for Photonanomedicine.

Photo-induced cancer therapies, mainly including photothermal therapy (PTT) and photodynamic therapy (PDT), have attracted numerous attentions owing to the high selectivity, convenience, and few side effects. However, single PTT usually requires high laser power density, and single PDT usually needs a high photosensitizer dosage. Herein, a kind of composite nanocarrier based on clay (laponite)-polypyrrole (LP) nanodisks was synthesized via the in situ polymerization of pyrrole in the interlayer space of laponite. LP composite nanodisks were then coated with polyvinylpyrrolidone (PVP) to form the LP-PVP (LPP) composite nanodisks which show an excellent colloidal stability and in vitro and in vivo biocompatibility. The interlayer space of LPP can be further used for the loading of Chlorin e6 (Ce6), with an ultrahigh loading capacity of about 89.2%. Furthermore, the LPP nanocarrier can enhance the PDT effect of Ce6 under the irradiation of a 660 nm laser, through enhancing its solubility and cellular uptake amount. Besides, it was found that LPP nanodisks exhibit a more outstanding photothermal performance under a 980 nm near-infrared laser (NIR) than a 808 nm NIR laser, with the photothermal conversion efficiency of 45.7 and 27.7%, respectively. The in vitro and in vivo tumor therapy results evidently confirm that the Ce6-loaded LPP nanodisks have a combined tumor PTT and PDT effect, which can significantly suppress the tumor malignant proliferation.

[Preparation of mixed-mode stationary phase for high performance liquid chromatography with ground hybrid silica monolithic material].

With polyethylene glycol as a porogen, vinyltrimethoxysilane (VTMS) and tetramethoxysilane (TMOS) as silica precursors, a hybrid silica monolithic material was obtained under the catalysis of acetic acid and thermally decomposed urea. The silica monolithic material was ground by a ballmill, treated with tris(hydroxymethyl)aminomethane (Tris), then washed and dried to obtain silica particles with particle size~3 µm. The effects of different reaction conditions on the particle size, surface morphology and dispersibility of silica particles were investigated. When the volume ratio of TMOS to VTMS was 3:1, it was observed that silica particles with a pore diameter of 7.5 nm and a specific surface area of 245 m2/g were obtained. The resultant silica particles were modified by binding with chlorodimethyloctadecylsilane (C18) and by the thiol-ene click reaction to obtain a mixed-mode type stationary phase. The test results showed that the silica packing materials prepared in this work has certain applicability.

Design, analysis, and testing of a novel compliant underactuated gripper.

This paper proposes a novel compliant underactuated gripper with multiple working modes. Based on the pseudo-rigid-body method, a static analysis of different working modes is carried out, establishing an analytical relationship between the output grasping forces and the input load. For the enveloped grasping mode, an algorithm to determine the static equilibrium position is given. Furthermore, a parametric optimization algorithm based on gradient descent is designed to obtain the maximum grasping forces. The effectiveness of the multiple grasping modes, the grasping force models, and the optimization algorithm are verified by a dynamic simulation package and finite element analysis as well as by experimental tests. Finally, various grasping experiments are conducted to further validate each working mode, the stability of grasping, and the ability to protect fragile objects.