Fabrication of Composite Polymer Foam Films at the Liquid/Liquid Interface through Emulsion-Directed Assembly and Adsorption Processes

Geng, Yuanyuan,Liu, Mei,Tong, Kun,Xu, Jian,Lee, Yong-Ill,Hao, Jingcheng,Liu, Hong-Guo American Chemical Society 2014 Langmuir Vol.30 No.8

<P>The foam films of polystyrene-<I>b</I>-poly(acrylic acid)-<I>b</I>-polystyrene (PS-<I>b</I>-PAA-<I>b</I>-PS) doped with Cd(II) or Pb(II) species were fabricated at the planar liquid/liquid interfaces between a DMF/chloroform (v/v: 1/1) solution of the polymer and aqueous solutions containing cadmium acetate or lead acetate at ambient temperature. Optical microscopic observation shows the thin film is uniform on a larger length scale. Transmission electron microscopic (TEM) investigations reveal that the foam films are made up of microcapsules with the size of several hundreds of nanometers to micrometers. The walls of the microcapsules have a layered structure decorating with nanofibers and hollow nanospheres, where numerous inorganic fine nanoparticles are dispersed homogeneously. The film formation is a result of emulsion droplet-templated assembly and adsorption of the formed microcapsules at the planar liquid/liquid interface. Because of the miscibility of DMF with chloroform and water, DMF migrates to the aqueous phase while water migrates to the organic phase across the interface, resulting in the formation of a W/O emulsion, as revealed by optical microscopic observation, freeze fracture transmission electron microscopic (FF-TEM) observation, and dynamic laser scattering (DLS) investigation. The triblock copolymer molecules and the inorganic species adsorb and self-assemble around the emulsion drops, leading to the formation of the composite microcapsules. X-ray photoelectron spectroscopic (XPS) and FTIR spectroscopic results indicate that two kinds of Cd(II) or Pb(II) species, metal oxide or hydroxide, resulting from the hydrolysis of the metal ions and the coordinated metal ions to the carboxyl groups coexist in the formed thin films, which transform to metal sulfide completely after treating with hydrogen sulfide to get metal sulfide nanoparticle-doped polymer thin films.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/langd5/2014/langd5.2014.30.issue-8/la500187d/production/images/medium/la-2014-00187d_0012.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/la500187d'>ACS Electronic Supporting Info</A></P>

Unique self-assembly behavior of a triblock copolymer and fabrication of catalytically active gold nanoparticle/polymer thin films at the liquid/liquid interface

Shang, Ke,Geng, Yuanyuan,Xu, Xingtao,Wang, Changwei,Lee, Yong-Ill,Hao, Jingcheng,Liu, Hong-Guo Elsevier 2014 Materials chemistry and physics Vol.146 No.1

Emulsion-directed liquid/liquid interfacial fabrication of lanthanide ion-doped block copolymer composite thin films

Hong, Ming,Geng, Yuanyuan,Liu, Mei,Xu, Yuan,Lee, Yong-Ill,Hao, Jingcheng,Liu, Hong-Guo Elsevier 2015 JOURNAL OF COLLOID AND INTERFACE SCIENCE - Vol.438 No.-

<P><B>Abstract</B></P> <P>An emulsion-directed assembly and adsorption approach has been used to fabricate composite films of polystyrene-b-poly(acryl acid)-b-polystyrene (PS-b-PAA-b-PS) and Eu<SUP>3+</SUP> and La<SUP>3+</SUP> ions at the planar liquid/liquid interface of the polymer DMF/chloroform (1:1, v/v) mixed solution (lower phase) and aqueous solutions of the corresponding salts (upper phase). The lower phase gradually transformed to a water-in-oil (W/O) emulsion via spontaneous emulsification due to the “ouzo effect”. Polymer molecules and the metal ions assembled around emulsion droplets that adsorbed at the planar liquid/liquid interface at last, resulting in formation of composite films. The film morphologies and structures depend on Ln<SUP>3+</SUP> ions: polymer/Eu<SUP>3+</SUP> composite films were foam films composed of microcapsules ranging in size from several hundreds of nanometers to micrometers, while polymer/La<SUP>3+</SUP> composite films were composed of hollow spheres several tens of nanometers in size. Fourier transform infrared (FTIR) spectra revealed that the coordination modes of carboxyl groups to Eu<SUP>3+</SUP> and La<SUP>3+</SUP> were bridging bidentate and ionic, respectively, in the two types of composites. These results indicate that stable microcapsules can be fabricated around droplets for polymer/Eu<SUP>3+</SUP> systems, while microcapsules of polymer/La<SUP>3+</SUP> are unstable. This leads to different film morphologies and structures. Compositions of these films were characterized using energy-dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). In addition, foam films of polymer/Eu<SUP>3+</SUP>/2,2′-bipyridine (bpy) were fabricated using this approach, and their photoluminescence properties were investigated.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Composite films of block copolymer/Ln<SUP>3+</SUP> were fabricated at liquid/liquid interfaces. </LI> <LI> Eu<SUP>3+</SUP> and La<SUP>3+</SUP> have great effects on morphologies and microstructures of the films. </LI> <LI> Polymer/Eu<SUP>3+</SUP> and polymer/Eu<SUP>3+</SUP>/bpy films exhibit good luminescent properties. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Epsilon-Fe₂O₃ is a novel intermediate for magnetite biosynthesis in magnetotactic bacteria

Tong Wen,Yunpeng Zhang,Yuanyuan Geng,Junquan Liu,Abdul Basit,Jiesheng Tian,Ying Li,Ji-Lun Li,Jing Ju,Wei Jiang 한국생체재료학회 2019 생체재료학회지 Vol.23 No.3

Background: Natural biological magnetite nanoparticles are widely distributed from microorganisms to humans. It is found to be very important in organisms, especially in navigation. Moreover, purified magnetite nanoparticles also have potential applications in bioengineering and biomedicine. Magnetotactic bacteria (MTB) is considered one of the most abundant species around the world which can form intracellular membrane enveloped magnetic nanoparticles, referred to as magnetosomes. To our knowledge, the biomineralization of magnetosome in MTB involves a serious of genes located on a large unstable genomic region named magnetosome island, which specially exists in MTB. The magnetite core of magnetosome formed via a Fe (III) ion intermediates, for instance, α-Fe2O3 and ferrihydrite. Though the biosynthesis of magnetosome represents a general biomineralization mechanism of biogenic magnetite, knowledge of magnetosome biosynthesis and biomineralization remains very limited. Method: Cells used in this study were cultured in a 7.5-L bioreactor, samples for intermediate capture were taken each certain time interval after the generation of magnetosome biosynthesis condition. High-resolution transmission electron microscopy were used to analyze the detailed structure of magnetosomes. The parameters of the crystal structures were obtained by Fast Fourier Transform analyses. Results: In this study, we identified a novel intermediate phase, ε-Fe2O3, during the magnetite maturation process in MTB via kinetic analysis. Unlike α-Fe2O3, which has been reported as a precursor during magnetosome biosynthesis in MTB before, ε-Fe2O3, due to its thermal instability, is a rare phase with scarce natural abundance. This finding confirmed that ε-Fe2O3 is an important novel intermediate during the biomineralization of magnetosome in MTB, and shed new light on the magnetosome biosynthesis pathway.

Liquid/Liquid Interfacial Fabrication of Thermosensitive and Catalytically Active Ag Nanoparticle-Doped Block Copolymer Composite Foam Films

Liu, Mei,Wang, Qian,Geng, Yuanyuan,Wang, Changwei,Lee, Yong-Ill,Hao, Jingcheng,Liu, Hong-Guo American Chemical Society 2014 Langmuir Vol.30 No.34

<P>An aqueous solution of AgNO<SUB>3</SUB> (upper phase) and a DMF/CHCl<SUB>3</SUB> solution of polystyrene-<I>b</I>-poly(acryl acid)-<I>b</I>-polystyrene (PS-<I>b</I>-PAA-<I>b</I>-PS) or PS-<I>b</I>-PAA-<I>b</I>-PS/1,6-diaminohexane (DAH) (lower phase) constituted a planar liquid/liquid interface. The lower phase gradually transformed to a water-in-oil (W/O) emulsion via spontaneous emulsification due to the “ouzo effect”. Polymer molecules, DAH molecules, and Ag<SUP>+</SUP> ions assembled into microcapsules around emulsion droplets that adsorbed at the planar liquid/liquid interface, resulting in formation of a foam film. DAH acted as a cross-linker during this process. Transmission electron microscopic observations indicated that Ag nanoclusters that were generated through reduction of Ag<SUP>+</SUP> ions by DMF were homogeneously dispersed in the walls of the foam structure. X-ray photoelectron spectroscopic investigations revealed that Ag(I) and Ag(0) coexisted in the film, and Ag(I) transformed to Ag(0) after further treatment. The film formed without DAH was not stable, while the film formed with DAH was very stable due to intermolecular attraction between PAA and DAH and formation of amides, as revealed by FTIR spectra. The film formed with DAH exhibited high and durable catalytic activity for hydrogenation of nitro compounds and, very interestingly, exhibited thermoresponsive catalytic behavior.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/langd5/2014/langd5.2014.30.issue-34/la502738j/production/images/medium/la-2014-02738j_0012.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/la502738j'>ACS Electronic Supporting Info</A></P>

Nanoarchitectonics of tannic acid based injectable hydrogel regulate the microglial phenotype to enhance neuroplasticity for poststroke rehabilitation

Zongjian Liu,Shulei Zhang,Yuanyuan Ran,Huimin Geng,Fuhai Gao,Guiqin Tian,Zengguo Feng,Jianing Xi,Lin Ye,Wei Su 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background Stroke is the second leading cause of mortality and disability worldwide. Poststroke rehabilitation is still unsatisfactory in clinics, which brings great pain and economic burdens to stroke patients. In this study, an injectable hydrogel in which tannic acid (TA) acts as not only a building block but also a therapeutic drug, was developed for poststroke rehabilitation. Methods TA is used as a building block to form an injectable hydrogel (TA gel) with carboxymethyl chitosan (CMCS) by multivalent hydrogen bonds. The morphology, rheological properties, and TA release behavior of the hydrogel were characterized. The abilities of the TA gel to modulate microglial (BV2 cells) polarization and subsequently enhance the neuroplasticity of neuro cells (N2a cells) were assessed in vitro. The TA gel was injected into the cavity of stroke mice to evaluate motor function recovery, microglial polarization, and neuroplasticity in vivo. The molecular pathway through which TA modulates microglial polarization was also explored both in vitro and in vivo. Results The TA gel exhibited sustainable release behavior of TA. The TA gel can suppress the expression of CD16 and IL-1β, and upregulate the expression of CD206 and TGF-β in oxygen and glucose-deprived (OGD) BV2 cells, indicating the regulation of OGD BV2 cells to an anti-inflammatory phenotype in vitro. This finding further shows that the decrease in synaptophysin and PSD95 in OGD N2a cells is effectively recovered by anti-inflammatory BV2 cells. Furthermore, the TA gel decreased CD16/iNOS expression and increased CD206 expression in the periinfarct area of stroke mice, implying anti-inflammatory polarization of microglia in vivo. The colocalization of PSD95 and Vglut1 stains, as well as Golgi staining, showed the enhancement of neuroplasticity by the TA gel. Spontaneously, the TA gel successfully recovered the motor function of stroke mice. The western blot results in vitro and in vivo suggested that the TA gel regulated microglial polarization via the NF-κB pathway. Conclusion The TA gel serves as an effective brain injectable implant to treat stroke and shows promising potential to promote poststroke rehabilitation in the clinic.

Three sesquiterpene lactones suppress lung adenocarcinoma by blocking TMEM16A-mediated Ca2+-activated Cl− channels

Ruilian Xiu,Jie Jia,Qing Zhang,Fengjiao Liu,Yaxin Jia,Yuanyuan Zhang,Beibei Song,Xiaodan Liu,Jingwei Chen,Dongyang Huang,Fan Zhang,Juanjuan Ma,Honglin Li,Xuan Zhang,Yunyun Geng 대한약리학회 2023 The Korean Journal of Physiology & Pharmacology Vol.27 No.6

Transmembrane protein TMEM16A, which encodes calcium-activated chloride channel has been implicated in tumorigenesis. Overexpression of TMEM16A is associated with poor prognosis and low overall survival in multiple cancers including lung adenocarcinoma, making it a promising biomarker and therapeutic target. In this study, three structure-related sesquiterpene lactones (mecheliolide, costunolide and dehydrocostus lactone) were extracted from the traditional Chinese medicine Aucklandiae Radix and identified as novel TMEM16A inhibitors with comparable inhibitory effects. Their effects on the proliferation and migration of lung adenocarcinoma cells were examined. Whole-cell patch clamp experiments showed that these sesquiterpene lactones potently inhibited recombinant TMEM16A currents in a concentration- dependent manner. The half-maximal concentration (IC50) values for three tested sesquiterpene lactones were 29.9 ± 1.1 μM, 19.7 ± 0.4 μM, and 24.5 ± 2.1 μM, while the maximal effect (Emax) values were 100.0% ± 2.8%, 85.8% ± 0.9%, and 88.3% ± 4.6%, respectively. These sesquiterpene lactones also significantly inhibited the endogenous TMEM16A currents and proliferation, and migration of LA795 lung cancer cells. These results demonstrate that mecheliolide, costunolide and dehydrocostus lactone are novel TMEM16A inhibitors and potential candidates for lung adenocarcinoma therapy.