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1.
ACS Appl Mater Interfaces ; 13(33): 39806-39818, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34387459

RESUMO

Silver nanomaterials have attracted a great deal of interest due to their broad-spectrum antimicrobial activity. However, it is still challenging to balance the high antibacterial efficiency with low damage to biological cells of silver nanostructures, especially when the diameter decreases to less than 10 nm. Here, we developed a new type of Ag nanohybrid material via a unimolecular micelle template method, which presents amazing antibacterial activities and almost noncytotoxicity. First, water-soluble multiarm star-shaped brushlike copolymer α-CD-g-[(PEO40-g-PAA50)-b-PEO5]18 was precisely synthesized and its micelle behavior in different solvents was revealed. Then, nanocrystal clusters assembled by Ag grains (Ag@Template NCs) were prepared through an in situ redox route using the unimolecular micelle of α-CD-g-[(PEO40-g-PAA50)-b-PEO5]18 as the soft template, AgNO3 as a precursor, and tetrabutylammonium borohydride (TBAB) as the reducing agent. The overall size of the achieved Ag@Template NCs is controlled by the template structure at around 40 nm (Dh in DMF), and the size of the Ag grain can be easily regulated from ∼1 to ∼5 nm by adjusting the feeding ratio of AgNO3/acrylic acid (AA) units in the template from 1:10 to 1:1. Benefitting from the structural design of the template, all Ag@Template NCs prepared here exhibit excellent dispersibility and chemical stability in different aqueous environments (neutral, pH = 5.5, and 0.9% NaCl physiological saline solution), which play a crucial role in the long-term storage and potential application in a complex physiological environment. The antibacterial and cytotoxicity tests indicate that Ag@Template NCs display much better performance than Ag nanoparticles (Ag NPs), which have a comparable overall size of ∼25 nm. The inhibitory capability of Ag@Template NCs to bacteria strongly depends on the grain size. Specifically, the Ag@Template-1 NC assembled by the smallest grains (1.6 ± 0.3 nm) presents the best antibacterial activity. For E. coli (-), the MIC value is as low as 5 µg/mL (0.36 µg/mL of Ag), while for S. aureus (+), the value is around 10 µg/mL (0.72 µg/mL of Ag). The survival rate of L02 cells and lactate dehydrogenase assay together illustrate the low cytotoxicity possessed by the prepared Ag@Template NCs. Therefore, the proposed Ag@Template NC structure successfully resolves the high reactivity, instability, and fast oxidation issues of the ultrasmall Ag nanoparticles, and integrates high antibacterial efficiency and nontoxicity to biological cells into one platform, which implies its broad potential application in biomedicine.


Assuntos
Antibacterianos/efeitos adversos , Antibacterianos/química , Nanopartículas Metálicas/química , Prata/química , Antibacterianos/metabolismo , Boroidretos/química , Sobrevivência Celular/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Polímeros/química , Compostos de Amônio Quaternário/química , Staphylococcus aureus/efeitos dos fármacos , Propriedades de Superfície , Nanomedicina Teranóstica
2.
Langmuir ; 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34431681

RESUMO

A colloidal nanocrystal cluster (CNC) is a hierarchical nanostructure formed by clustering several nanocrystals into one nano-ensemble, which may exhibit unique optical or catalytic properties different from individual nanocrystals owing to the mutual interactions among neighboring component nanocrystals. However, there is still no universal synthetic route that could be applicable to diverse material compositions with precisely controlled hierarchical structures (i.e., nanocrystal number density, component nanocrystal size, and overall diameter of the CNC) up to now. Herein, a general and novel synthetic strategy was reported for crafting a wide range of inorganic CNCs (i.e., noble metal, semiconductor, and metal oxide) via utilizing amphiphilic star-like poly(4-vinylpyridine)-block-polystyrene diblock copolymers as nanoreactors prepared by sequential atom transfer radical polymerization. The hierarchical structure of rationally designed CNCs could be readily tailored by varying the P4VP molecular weight of star-like nanoreactors and the parameter optimization during the CNC preparation process, which was inaccessible by conventional synthetic methods.

3.
J Colloid Interface Sci ; 600: 421-429, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34023703

RESUMO

Multi-stimuli responsive fluorescence probe could pave the way for monitoring more complex environmental changes. Here we prepared multifunctional nanoparticle Fe3O4@SiO2@P(DMAEMA-co-TPEE), which displayed yolk-shell morphology with well-defined polymer brush. With superparamagnetic Fe3O4 component and pH/temperature dual sensitive PDMAEMA polymer brush, the as prepared nanoparticles (YS-NPs) exhibited as multi-stimuli responsive fluorescence probe for real-time visual monitoring of environmental changes such as magnetic field, temperature and pH. Such YS-NPs could also be applied as a sensitive detector for CO2 in aqueous solution. Notably, the solution of YS-NPs showed high colloidal stability during the environmental changes, and surface aggregation-induced emission (S-AIE) was proposed for the aggregation of TPE residue on the surface of YS-NPs.


Assuntos
Nanocompostos , Nanopartículas , Polímeros , Temperatura
4.
J Phys Chem Lett ; : 3456-3463, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33792312

RESUMO

The past few years witnessed the rapid development of bottom-up synthesis strategies for preparing various nanostructures (i.e., nanoparticles, nanorods, nanowires, etc.) with distinct morphology-dependent properties. In this study, we reported a facile and efficient synthesis method for preparing anatase titanium dioxide (TiO2) nanorings based on multiarm, starlike amphiphilic polystyrene-b-poly(acrylic acid) (PS-b-PAA) diblock copolymers as nanoreactors which were prepared via a sequential atom-transfer radical polymerization (ATRP) technique followed by the conversion of polystyrene-b-poly(tert-butyl acrylate) (PS-b-PtBA) to PS-b-PAA. The outer PAA block of nanoreactors possessed carboxylic acid groups which could coordinate with a titanium precursor followed by high-temperature calcination to form crystalline TiO2 nanorings. The living nature of ATRP enabled the precise preparation of starlike diblock copolymer nanoreactors with a controlled length of each block (i.e., PtBA and PS), thereby tailoring the inner diameter and wall thickness of the resulting TiO2 nanorings, which were inaccessible to conventional routes.

5.
ACS Appl Mater Interfaces ; 12(37): 42161-42168, 2020 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-32840349

RESUMO

Silicon quantum dots (SiQDs) are explored for the first time as an efficient photocatalyst for visible-light-regulated reversible addition-fragmentation chain transfer (RAFT) polymerization. The fluorescence quenching confirmed the photoinduced electron transfer (PET) between SiQDs and RAFT reagents. Besides all features of controlled radical polymerization, the SiQDs catalyzed PET-RAFT polymerization also exhibit good temporal control, high chain-end fidelity, and versatility with diverse monomers. Moreover, amino-functionalized SiQDs can be easily coated on the surface of substrates (silicon wafer) owing to the electrostatic interaction, and play a dual role of polymer-substrate connector and photocatalyst for the surface-initiated PET-RAFT polymerization. The SiQD-coated wafer was also proved to be an efficient recycle photocatalyst for PET-RAFT polymerization.

6.
Langmuir ; 36(24): 6690-6697, 2020 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-32493013

RESUMO

We reported the synthesis of a well-defined hollow polymer nanoparticle derived from star-shaped unimolecular micelles. ß-Cyclodextrin was first applied as an efficient macroinitiator to prepare a star-shaped PCL via ring-opening polymerization (ROP). Then, the star-shaped PCL was modified to be a macro-RAFT agent for photoinduced electron/energy transfer-reversible addition-fragmentation chain transfer (PET-RAFT) polymerization of S-Cl monomers. The prepared unimolecular micelles can be photocross-linked under UV irradiation after a simple nucleophilic substitution reaction, which made -Cl groups to be -N3 groups. After the selective removal of the PCL core, hollow polymer nanoparticles were achieved and exhibited to be a general nanoreactor strategy for the fabrication of nanocrystals with well-controlled architectures. Compared with unimolecular micelle templates, the nanocrystals prepared by hollow templates are absolutely pure as no polymer chains are embedded in the inorganic nanocrystals. In addition, by changing the concentration of the precursor, the structure of the nanocrystal can be changed from a normal spherical structure to a hollow structure.

7.
Chem Asian J ; 15(7): 1014-1017, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32012458

RESUMO

Aggregation-induced emission (AIE) technology has been demonstrated to be a facile approach for in-situ monitoring atom transfer radical polymerization (ATRP). A series of tertraphenyl ethylene (TPE)-containing α-bromo compounds were synthesized and applied as ATRP initiators. The photoluminescent (PL) emission of the polymerization system is proved to be sensitive to the local viscosity owing to the AIE characteristics of TPE. Linear relationships between the resulting molecular weight Mn and PL intensity were observed in several polymerization systems with different monomers, indicating the variability of this technique. Compared to physical blending, the chemical bonding of the TPE group in the chain end has higher sensitivity and accuracy to the polymer segments and the surrounding environment. This work promoted the combination of the AIE technique and controlled living radical polymerization, and introduced such an optical research platform to the ATRP polymerization process.

8.
J Chromatogr A ; 1601: 310-318, 2019 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-31054832

RESUMO

Efficient separation of aromatic amine isomers is a challenging issue in chemical industry and environmental analysis. Here we report the use of p-amino-tetradecyloxy-calix[4]arene (C4A-NH2) as a novel stationary phase for gas chromatographic (GC) separations. The statically coated C4A-NH2 capillary column showed a high column efficiency of 4332 plates/m for a 0.25 mm ID column and medium polarity. The C4A-NH2 stationary phase exhibited an excellent separation performance both for aromatic amine isomers and a complex mixture of aliphatic analytes with a wide ranging polarity, showing distinct advantages over the commercial polysiloxane stationary phases via diversified molecular interactions covering H-bonding, π-π, van der Waals interactions and shape-fitting selectivity. The retention mechanisms of aromatic amine isomers on C4A-NH2 column were further investigated by quantum chemistry calculations. In addition, the C4A-NH2 column showed good column repeatability with relative standard deviation (RSD) values of 0.03%-0.07% for run-to-run, 0.10%-0.27% for day-to-day and 2.6%-5.7% for column-to-column, respectively, and thermal stability up to 240℃.


Assuntos
Aminas/análise , Calixarenos/química , Fenóis/química , Aminas/química , Cromatografia Gasosa/métodos , Isomerismo , Reprodutibilidade dos Testes , Siloxanas/química
9.
Artigo em Inglês | MEDLINE | ID: mdl-30616167

RESUMO

Bacillus anthracis spore causes anthrax to seriously threaten human health and even cause death. 2,6-Pyridinedicarboxylic acid (DPA) is a unique biomarker because it is a major component of Bacillus anthracis spore. Herein, we design europium functionalized silicon quantum dots as a ratiometric fluorescent nanoprobe to detect DPA with high sensitivity and selectivity. With the addition of DPA, the red emission peaks were observed at 618 nm. The novel probe enables ratiometric and sensitive DPA detection over nanomolar concentrations (as low as 1.02 µM). This work provided an efficient background-free and self-calibrating method for the recognition of DPA.


Assuntos
Bacillus anthracis/metabolismo , Biomarcadores/análise , Európio/química , Nanoestruturas/química , Pontos Quânticos/química , Silício/química , Fluorescência , Concentração de Íons de Hidrogênio , Nanoestruturas/ultraestrutura , Tamanho da Partícula , Piridinas/química , Padrões de Referência , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Eletricidade Estática
10.
Spectrochim Acta A Mol Biomol Spectrosc ; 204: 196-202, 2018 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-29935390

RESUMO

Due to the importance of hypochlorous acid (HClO) in biological and industrial, development of fluorescent probes for HClO has been an active research area. Here, a new red-emitting ratiometric fluorescent probe (P) was synthesized and well defined characterization via NMR, HR-MS, and fluorescence spectrum, which serves as a selective and sensitive probe for ClO- group. The probe showed a ratiometric fluorescent response to hypochlorite at the emission intensities ratio (I480/I612) increasing from 0.28 to 27.46. The emission intensities ratio (I480/I612) was linearly enhanced (I480/I612 = 0.064 X + 0.096) with the ClO- concentration range from 1 to 30 µM. The detection limitation for ClO- in aqueous solution is 0.47 µM. Moreover, this biocompatible red-emitting ratiometric fluorescent probe was utilized to the fluorescence imaging of ClO- in living cells and Zebrafish.


Assuntos
Corantes Fluorescentes/química , Ácido Hipocloroso/análise , Animais , Sobrevivência Celular/efeitos dos fármacos , Embrião não Mamífero/diagnóstico por imagem , Corantes Fluorescentes/toxicidade , Células HeLa , Humanos , Limite de Detecção , Modelos Lineares , Microscopia de Fluorescência , Reprodutibilidade dos Testes , Peixe-Zebra
11.
Steroids ; 134: 101-109, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29476759

RESUMO

A series of new estrone derivatives were designed and synthesized, and their structures were confirmed by spectroscopic methods. All new estrone derivatives were investigated for their in vitro cytotoxic efficacies against a panel of three human prostate cancer cell lines (PC-3, LNCaP, and DU145). The derivatives 6, 7, 10, 15, 16, 20, 21, 22, 24 and 26 showed important cytotoxic actions against individual carcinoma cell line collections. Moreover, antagonistic activities of compounds (7, 15, 16 and 21) towards a1-ARs (α1A, α1B, and α1D) were further evaluated using dual-luciferase reporter assays, and the compounds 16 and 21 exhibited better a1-ARs subtype selectivity. The structure-activity relationship (SAR) suggested that the substitute's type and position on the phenyl group leads to the interesting variations within pharmacological effects of resultant molecular systems.


Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Estrona/síntese química , Estrona/farmacologia , Éter/química , Piperazinas/química , Antineoplásicos/química , Linhagem Celular Tumoral , Técnicas de Química Sintética , Estrona/química , Humanos , Piperazina , Relação Estrutura-Atividade
12.
Sci Rep ; 7: 40846, 2017 01 30.
Artigo em Inglês | MEDLINE | ID: mdl-28134297

RESUMO

High performance Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr alloy with high strength and excellent ductility has been successfully developed by hot extrusion. The effect of plate-shaped long period stacking ordered (LPSO) phases and solute-segregated stacking faults (SFs) on the dynamically recrystallization (DRX) behavior was analyzed. The plate-shaped LPSO phases stimulate the DRX by particle stimulated nucleation mechanism, leading to higher DRX ratio and weaker basal texture. While for the alloy with dense fine SFs inside the original grains, discontinuous DRX initially occurs at the original grain boundaries, and the DRX is obviously restricted. Consequently, alloy containing dense SFs exhibits higher strength but lower ductility compared with alloy with plated-shaped LPSO phases.

13.
Zhongguo Gu Shang ; 24(5): 374-7, 2011 May.
Artigo em Chinês | MEDLINE | ID: mdl-21688531

RESUMO

OBJECTIVE: To summarize the therapeutic experience and analyse the clinical effects of anatomical plate and combined external fixator for the treatment of elderly intertrochanteric hip fractures. METHODS: From Oct.2006 to Jun.2009, 42 patients with intertrochanteric hip fractures were treated. Among them, 19 patients were treated with combined external fixator, included 7 males and 12 females, aged from 71 to 103 years old; according to Evans classification there were 3 of type 1, 5 of type II, 6 of type III, 5 of type IV. The other 23 patients were treated with anatomical plate, included 9 males and 14 females, aged from 73 to 97 years old; there were 5 of type I , 4 of type II, 10 of type II, 2 of type IV, 2 of type V. Comparisons and statistical analysis were made on operation time, blood loss during operation, hospitalization time, the time of loaded walking, fracture healing time and therapeutic effect. RESULTS: All the patients were followed up for 6 to 15 months with an average of 8.6 months. In combined external fixator group, the average operation time was (29.368 +/- 3.253) min, the average blood loss during operation was (30.526 +/- 5.242) ml, the average hospitalization time was (4.368 +/- 1.165) d, the average time of loaded walking was (14.526 +/- 1.867) weeks, the fracture healing time was (14.632 +/- 2.798) weeks; in the anatomical plate group above-mentioned indexes were (58.987 +/- 8.600) min, (256.090 +/- 30.112) ml, (13.783 +/- 1.976) d, (11.391+/- 1.644) weeks, (11.391 +/- 2.327) weeks,respectively; and there were significant differences between two groups (P<0.05). According to Harris score criterion, the scores of combined external fixator group was (86.368 0 +/- 3.640) scores,and the scores of anatomical plate group was (86.435 +/- 4.198) scores; there were no significant differences between two groups (P>0.05). CONCLUSION: The effect of combined external fixator and anatomical plate for the elderly intertrochanteric hip fractures are both satisfactory and each has its own merits. Combined external fixator has advantages such as fewer complications and operative injuries than that of anatomical plate and is more suitable for the weaker with elderly intertrochanteric hip fractures.


Assuntos
Placas Ósseas , Fixação de Fratura/métodos , Fraturas do Quadril/cirurgia , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Fixação de Fratura/efeitos adversos , Fixação de Fratura/instrumentação , Fraturas do Quadril/fisiopatologia , Humanos , Masculino , Complicações Pós-Operatórias , Estudos Retrospectivos , Resultado do Tratamento , Suporte de Carga
14.
Langmuir ; 22(24): 10175-9, 2006 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-17107018

RESUMO

Organic-inorganic hybrid particles have many potential applications, but almost all of this research was focused on the hybrid particles containing one kind of inorganic nanoparticles. This paper presented a facile preparation method for SiO2/PS/TiO2 multilayer core-shell hybrid microspheres. In this approach, positively charged SiO2/PS core-shell hybrid particles were first synthesized by miniemulsion polymerization using cationic initiator and emulsifier. These positively charged SiO2/PS hybrid particles were mixed with tetra-n-butyl titanate for sol-gel reaction to directly form SiO2/PS/TiO2 multilayer core-shell hybrid microspheres. Some influencing parameters such as surfactant concentration, tetra-n-butyl titanate amount, and glacial acetic acid amount were investigated. TEM, TGA, and EDX analyses indicated that titania layers were successfully coated onto the surfaces of hybrid microspheres.

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