Co-reporter:Yuqing Wu, Ke Wang, Haiying Tan, Jiangping Xu, and Jintao Zhu
Langmuir September 26, 2017 Volume 33(Issue 38) pp:9889-9889
Publication Date(Web):August 24, 2017
DOI:10.1021/acs.langmuir.7b02330
A simple yet efficient method is developed to manipulate the self-assembly of pH-sensitive block copolymers (BCPs) confined in emulsion droplets. Addition of acid induces significant variation in morphological transition (e.g., structure and surface composition changes) of the polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) assemblies, due to the hydrophobic–hydrophilic transition of the pH-sensitive P4VP block via protonation. In the case of pH > pKa(P4VP) (pKa (P4VP) = 4.8), the BCPs can self-assemble into pupa-like particles because of the nearly neutral wetting of PS and P4VP blocks at the oil/water interface. As expected, onion-like particles obtained when pH is slightly lower than pKa(P4VP) (e.g., pH = 3.00), due to the interfacial affinity to the weakly hydrophilic P4VP block. Interestingly, when pH was further decreased to ∼2.5, interfacial instability of the emulsion droplets was observed, and each emulsion droplet generated nanoscale assemblies including vesicles, worm-like and/or spherical micelles rather than a nanostructured microparticle. Furthermore, homopolymer with different molecular weights and addition ratio are employed to adjust the interactions among copolymer blocks. By this means, particles with hierarchical structures can be obtained. Moreover, owing to the kinetically controlled processing, we found that temperature and stirring speed, which can significantly affect the kinetics of the evaporation of organic solvent and the formation of particles, played a key role in the morphology of the assemblies. We believe that manipulation of the property for the aqueous phase is a promising strategy to rationally design and fabricate polymeric assemblies with desirable shapes and internal structures.
Co-reporter:Qianqian Liu, Nan Xu, Liping Liu, Jun Li, Yamin Zhang, Chen Shen, Khurram Shezad, Lianbin Zhang, Jintao Zhu, and Juan Tao
ACS Applied Materials & Interfaces July 5, 2017 Volume 9(Issue 26) pp:21673-21673
Publication Date(Web):June 7, 2017
DOI:10.1021/acsami.7b05278
Dacarbazine (DTIC) is one of the most important chemotherapeutic agents for the treatment of melanoma; however, its poor solubility, photosensitivity, instability, and serious toxicity to normal cells limit its clinical applications. In this article, we present a rationally designed nanocarrier based on hollow mesoporous silica nanoparticles (HMSNs) for the encapsulation and targeted release of DTIC for eradicating melanoma. The nanocarrier (DTIC@HMLBFs) is prepared by modifying HMSNs with carboxyl groups to enhance the loading of DTIC, followed by further enveloping of folic acid-grafted liposomes, which act as a melanoma active target for controlled and targeted drug release. In vitro, DTIC@HMLBFs exhibited the strongest cytotoxicity to melanoma cells compared with DTIC@HMSNs and free DTIC. The in vivo investigations demonstrate that the rationally designed nanocarrier loaded with DTIC achieves significant improvement against lung metastasis of melanoma via targeting melanoma cells and tumor-associated macrophages. This study provides a promising platform for the design and fabrication of multifunctional nanomedicines, which are potentially useful for the treatment of melanoma.Keywords: Dacarbazine; folic acid; hollow mesoporous silica nanoparticles; melanoma; target delivery;
Co-reporter:Mubashir Hussain, Jun Xie, Zaiyan Hou, Khurram Shezad, Jiangping Xu, Ke Wang, Yujie Gao, Lei Shen, and Jintao Zhu
ACS Applied Materials & Interfaces April 26, 2017 Volume 9(Issue 16) pp:14391-14391
Publication Date(Web):April 3, 2017
DOI:10.1021/acsami.7b02002
Generally, size, uniformity, shape, and surface chemistry of biodegradable polymer particles will significantly affect the drug-release behavior in vitro and in vivo. In this study, uniform poly(d,l-lactic-co-glycolide) (PLGA) and PLGA-b-poly(ethylene glycol) (PLGA-b-PEG) microparticles with tunable surface textures were generated by combining the interfacial instabilities of emulsion droplet and polymer-blending strategy. Monodisperse emulsion droplets containing polymers were generated through the microfluidic flow-focusing technique. The removal of organic solvent from the droplets triggered the interfacial instabilities (spontaneous increase in interfacial area), leading to the formation of uniform polymer particles with textured surfaces. With the introduction of homopolymer PLGA to PLGA-b-PEG, the hydrophobicity of the polymer system was tailored, and a qualitatively different interfacial behavior of the emulsion droplets during solvent removal was observed. Uniform polymer particles with tunable surface roughness were thus generated by changing the ratio of PLGA-b-PEG in the polymer blends. More interestingly, surface textures of the particles determined the drug-loading efficiency and release kinetics of the encapsulated hydrophobic paclitaxel, which followed a diffusion-directed drug-release pattern. The polymer particles with different surface textures demonstrated good cell viability and biocompatibility, indicating the promising role of the particles in the fields of drug or gene delivery for tumor therapy, vaccines, biodiagnostics, and bioimaging.Keywords: controlled release; drug loading; Microfluidics; microparticles; polymer blends; rough surface;
Co-reporter:Jiangping Xu;Yi Yang;Ke Wang;Yuqing Wu
Materials Chemistry Frontiers 2017 vol. 1(Issue 3) pp:507-511
Publication Date(Web):2017/03/09
DOI:10.1039/C6QM00072J
In this communication, we report a facile yet effective approach to fabricate polystyrene-b-poly(4-vinyl pyridine) (PS-b-P4VP) convex lens (CL)-like microparticles with hexagonally stacked cylindrical P4VP domains via three-dimensional confined assembly. Addition of a hydrogen bonding agent, 3-n-pentadecylphenol (PDP), not only changes the volume fraction of the P4VP domain, but also alters the interfacial interactions between the blocks and the surfactant. A neutral interface could be created by tuning the content of PDP, resulting in the formation of CL-like microparticles. Selective swelling and then deswelling of these particles offers us a convenient way to synthesize isoporous particles with tunable pore size, potentially useful in ultrafiltration with high selectivity.
Co-reporter:Ruijing Liang, Jun Xie, Jun Li, Ke Wang, Liping Liu, Yujie Gao, Mubashir Hussain, Guanxin Shen, Jintao Zhu, Juan Tao
Biomaterials 2017 Volume 149(Volume 149) pp:
Publication Date(Web):1 December 2017
DOI:10.1016/j.biomaterials.2017.09.029
For nanovaccine-based cancer immunotherapy, dendritic cells (DCs) are one of the most powerful antigen presenting cells (APCs) that initiate and promote the maturation of antigen-specific cytotoxic T lymphocytes (e.g., CD8+ T cells) to induce the local and systemic antitumor immunity and further suppress the tumor metastasis and produce long-term protection against tumor. Thus, the activation and maturation of DCs is the prerequisite for efficient CD8+ T cell-based antitumor immune responses, which is considered as a primary and promising task for nanovaccine engineering. Herein, we introduce a versatile nanovaccine of liposomes-coated gold nanocages (Lipos-AuNCs) modified with DCs specific antibody aCD11c for targeted delivery of adjuvant MPLA and melanoma antigen peptide TRP2 to promote the activation and maturation of DCs, and enhance tumor specific T lymphocytes responses. Moreover, AuNCs accumulation and AuNCs-engulfed DCs migration to regional lymph nodes (RLNs) became real-time visualization through in vivo fluorescence and photoacoustic (PA) imaging to monitor the immunity process. In vivo experimental results demonstrated that the targeted antigen/adjuvants-loaded AuNCs exhibited enhanced antitumor immune response to inhibit tumor growth and metastasis in both B16-F10 prophylactic and lung metastasis models, which may act as a promising nanoplatform for antitumor immunotherapy and in vivo tracking.Download high-res image (298KB)Download full-size image
Co-reporter:Lei Shen, Jintao Zhu
Advances in Colloid and Interface Science 2016 Volume 228() pp:40-54
Publication Date(Web):February 2016
DOI:10.1016/j.cis.2015.11.008
Highlights
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We summarize the recent achievements and discuss the new perspectives in the research of developing heterogeneous surfaces to repel proteins.
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We discuss the protein repulsion mechanisms behind heterogeneous surfaces.
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We outline the perspective and challenge of heterogeneous surfaces as the next-generation protein-repulsive materials.
Co-reporter:Lei Shen
Macromolecular Rapid Communications 2016 Volume 37( Issue 6) pp:494-499
Publication Date(Web):
DOI:10.1002/marc.201500687
Co-reporter:Jiangping Xu, Yuqing Wu, Ke Wang, Lei Shen, Xiaolin Xie and Jintao Zhu
Soft Matter 2016 vol. 12(Issue 16) pp:3683-3687
Publication Date(Web):30 Mar 2016
DOI:10.1039/C5SM03071D
Here we present a facile yet robust strategy to prepare polymer nano-bowls through 3D confined assembly and disassembly of block copolymers. Unlike the previously reported methods, this strategy allows for generation of nano-bowls with precisely controllable opening degree and thickness. Typically, polystyrene-b-poly(4-vinyl pyridine) (PS-b-P4VP) nano-bowls can be generated through confined assembly of PS-b-P4VP with homopolystyrene (hPS) to form Janus particles, followed by the crosslinking of P4VP domains and disassembly of PS domains. The opening degree of the nano-bowls can be precisely controlled by the weight fraction of hPS, and the thickness can be tailored by the varying molecular weight of PS-b-P4VP. By selectively loading gold nanoparticles in P4VP domains, it is anticipated that the resulting hybrid nano-bowls would be useful for surface enhanced Raman scattering and potential catalytic reaction applications.
Co-reporter:Xiaolu Jia, Ke Wang, Jianying Wang, Yuandu Hu, Lei Shen, Jintao Zhu
European Polymer Journal 2016 Volume 83() pp:60-66
Publication Date(Web):October 2016
DOI:10.1016/j.eurpolymj.2016.08.006
•We apply a fast and efficient route to prepare photonic hydrogels for pH and ionic strength sensing.•Composite photonic hydrogels with linearly ordered nanoparticles arrays are obtained.•Hydrolization of PHEMA into PAA units endows the hydrogels with pH and ion sensing functionalities.•Fixed number of carboxyl groups in the hydrogels is obtained by controlling the content of PHEMA.•The photonic hydrogels demonstrate good reproducibility and sensing ability.We demonstrate a facile yet efficient strategy to fabricate responsive photonic hydrogels by incorporating magnetic (Fe3O4) nanoparticles into the hydrogel materials. In this approach, poly(acrylamide)-poly(2-hydroxyethyl methacrylate) (PAM-PHEMA) photonic hydrogels incorporated with linearly ordered Fe3O4 nanocrystal arrays were successfully synthesized via one-step polymerization process under an external magnetic field. The resulting hydrogel materials can be endowed with pH and ion sensing functionalities by hydrolyzing PHEMA into PAA units in sodium carbonate aqueous solutions. The whole fabrication process of the photonic hydrogels would take only ∼2.5 h, including dispersing Fe3O4 NPs in monomer solution for ∼10 min, photo-polymerization for ∼20 min, hydrolyzation of PHEMA for ∼2 h. Importantly, photonic hydrogels containing fixed number of carboxyl groups can be fabricated by controlling the content of PHEMA. The photonic hydrogels demonstrate better reproducibility and keep the same pH and ionic strength sensing abilities, which is beneficial for batch preparation.
Co-reporter:Renhua Deng, Hui Li, Jintao Zhu, Baohui Li, Fuxin Liang, Fan Jia, Xiaozhong Qu, and Zhenzhong Yang
Macromolecules 2016 Volume 49(Issue 4) pp:1362-1368
Publication Date(Web):February 9, 2016
DOI:10.1021/acs.macromol.5b02507
We present a facile approach toward straightforward synthesis of Janus nanoparticles (NPs) of poly(4-vinylpyridine)-based block copolymers by solvent evaporation induced assembly within emulsion droplets. Formation of the Janus NPs is arisen from the synergistic effect between solvent selectivity and interfacial selectivity. This method is robust without the requisites of narrow molecular weight distribution and specific range of block fraction of the copolymers. Janus NPs can also be achieved from mixtures of copolymers, whose aspect size ratio and thus Janus balance are finely tunable. The Janus NPs are capable to self-assemble into ordered superstructures either onto substrates or in dispersions, whose morphology relies on Janus balance.
Co-reporter:Ke Wang, Seon-Mi Jin, Jiangping Xu, Ruijing Liang, Khurram Shezad, Zhigang Xue, Xiaolin Xie, Eunji Lee, and Jintao Zhu
ACS Nano 2016 Volume 10(Issue 5) pp:4954
Publication Date(Web):April 7, 2016
DOI:10.1021/acsnano.6b00487
In this report, we demonstrate the confined assembly of polymer-tethered gold nanorods in anodic aluminum oxide (AAO) channels with the assistance of electric field (EF). Various interesting hybrid assemblies, such as single-, double-, triple-, or quadruple-helix, linear, and hexagonally packed structures are obtained by adjusting pore size in AAO channels, ligand length, and EF orientation. Correspondingly, surface plasmonic property of the assemblies can thus be tuned. This strategy, by coupling of external-field and cylindrically confined assembly, is believed to be a promising approach for generating ordered hybrid assemblies with hierarchical structures, which may find potential applications in photoelectric devices, biosensors, and data storage devices.Keywords: confined assembly; cylindrical confinement; electric field; gold nanorods; helix structure
Co-reporter:Lei Shen, Jun Xie, Juan Tao and Jintao Zhu
Journal of Materials Chemistry A 2015 vol. 3(Issue 6) pp:1157-1162
Publication Date(Web):09 Dec 2014
DOI:10.1039/C4TB01905A
We develop a novel heterogeneous pattern with nanometer-sized spots surrounded with a bio-inert matrix by using a diblock copolymer thin film. The nanopattern with features down to 20 nm is highly resistant to protein adsorption and cell adhesion. By providing a domelike topography similar to biologically relevant size, such a heterogeneous nanopattern demonstrates an excellent anti-biofouling property to control protein–surface and cell–surface interactions at the molecular level.
Co-reporter:Yali Wang, Chengnian Li, Xuehao He and Jintao Zhu
RSC Advances 2015 vol. 5(Issue 46) pp:36680-36686
Publication Date(Web):17 Apr 2015
DOI:10.1039/C5RA04110D
This report proposed a promising method that combined microfluidic techniques, phase separation and selective dissolution to prepare uniform concave polystyrene (PS) microparticles. Monodisperse emulsion droplets containing PS and poly(methyl methacrylate) (PMMA) in chloroform were firstly obtained using a microcapillary-based microfluidic device. Uniform PS/PMMA Janus composite particles were then generated through the phase separation between PS and PMMA within the emulsion droplets during organic solvent evaporation. Subsequently, uniform PS concave particles were obtained through selective dissolution of the PMMA domain in the Janus composite particle with acetic acid. Moreover, depletion-mediated directional self-assembly of the prepared concave PS particles was investigated, and polymeric worm-like chains with head-to-tail configuration were observed.
Co-reporter:Jiangping Xu, Ke Wang, Ruijing Liang, Yi Yang, Huamin Zhou, Xiaolin Xie, and Jintao Zhu
Langmuir 2015 Volume 31(Issue 45) pp:12354-12361
Publication Date(Web):October 22, 2015
DOI:10.1021/acs.langmuir.5b03146
In this study, we report the controllable structural transformation of block copolymer/homopolymer binary blends in cylindrical nanopores. Polystyrene-b-poly(4-vinylpyridine)/homopolystyrene (SVP/hPS) nanorods (NRs) can be fabricated by pouring the polymers into an anodic aluminum oxide (AAO) channel and isolated by selective removal of the AAO membrane. In this two-dimensional (2D) confinement, SVP self-assembles into NRs with concentric lamellar structure, and the internal structure can be tailored with the addition of hPS. We show that the weight fraction and molecular weight of hPS and the diameter of the channels can significantly affect the internal structure of the NRs. Moreover, mesoporous materials with tunable pore shape, size, and packing style can be prepared by selective solvent swelling of the structured NRs. In addition, these NRs can transform into spherical structures through solvent-absorption annealing, triggering the conversion from 2D to 3D confinement. More importantly, the transformation dynamics can be tuned by varying the preference property of surfactant to the polymers. It is proven that the shape and internal structure of the polymer particles are dominated by the interfacial interactions governed by the surfactants.
Co-reporter:Jingyi Li, Lingzhi Chen, Jiangping Xu, Ke Wang, Xiaofan Wang, Xiaohua He, Hai Dong, Shaoliang Lin, and Jintao Zhu
Langmuir 2015 Volume 31(Issue 48) pp:13094-13100
Publication Date(Web):November 9, 2015
DOI:10.1021/acs.langmuir.5b03610
Here we present the generation of uniform microparticles with tunable diameters from azobenzene-based homopolymer by combining the microfluidics technique and emulsion-solvent evaporation route. In addition, the photoinduced deformation behavior of these microspheres, irradiated by a linearly polarized beam with different irradiation time and direction, are systemically studied. The deformation process through real time optical microscope observation can be investigated, benefiting from the uniform and microscaled size of the polymer particles. These results indicate that the deformation degree characterized by relative variation of the long axial for the particles can be controlled by the irradiation time. Moreover, elongated particles with tunable aspect ratio or tilted shape can be generated by manipulating the irradiation direction and/or time. Interestingly, the shape transformation kinetics displays a significant dependence on initial size of the polymer particle. In addition, the shape transformation of the polymer particle can lead to the variation of the orientation and distribution of the encapsulated anisotropic gold nanorods.
Co-reporter:Ruijing Liang, Jiangping Xu, Weikun Li, Yonggui Liao, Ke Wang, Jichun You, Jintao Zhu, and Wei Jiang
Macromolecules 2015 Volume 48(Issue 1) pp:256-263
Publication Date(Web):December 19, 2014
DOI:10.1021/ma501835r
Localization of inorganic nanoparticles (NPs) into polymer matrix plays a crucial role in determining the performance of the hybrid materials. Herein, we employed a simple, yet versatile hydrogen bonding directed supramolecular assembly (HBSA) strategy to control the localization of Au NPs from the center to the interface in polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) cylindrical micellar aggregates by tailoring the selectivity of polymer brushes on the surface of Au NPs. PS-b-P4VP(PDP)x comb–coil supramolecules were constructed by PS-b-P4VP and n-pentadecylphenol (PDP) via the hydrogen bonding between the pyridine of P4VP and the hydroxyl of PDP. PS-tethered Au NPs (PS-Au NPs) were selectively localized in the PS domain while a binary mixture of PS and P4VP-tethered Au NPs (PS/P4VP-Au NPs) were adsorbed to the interface between PS and P4VP(PDP)x domains presumably due to the redistribution of PS and P4VP ligands on the Au NPs surface, triggering the formation of amphiphilic surfactant-like NPs. Isolated cylindrical micellar aggregates with controlled localization of Au NPs were obtained by the selective disassembly of the supramolecules. Moreover, supramolecular block domain size, composition of the supramolecules, size of the Au NPs, and volume fraction of the Au NPs were carefully investigated to reveal their effects on the morphology of hybrid micellar aggregates and localization of NPs. These hybrid micellar aggregates with controlled localization and loading efficiency of Au NPs may extend the applications of the hybrid micellar aggregates and find more potential uses in optical/electronic devices, catalysis, and drug delivery system.
Co-reporter:Jiangping Xu, Ke Wang, Jingyi Li, Huamin Zhou, Xiaolin Xie, and Jintao Zhu
Macromolecules 2015 Volume 48(Issue 8) pp:2628-2636
Publication Date(Web):April 10, 2015
DOI:10.1021/acs.macromol.5b00335
Here we present 3D confined assembly of polystyrene-b-polyisoprene-b-poly(2-vinylpyridine) (PS-b-PI-b-P2VP) ABC triblock copolymers into particles with tunable shape and internal structures. Under weak confinement (i.e., ratio of the particle size to the periodicity dimension of the block copolymer D/L0 > 4), surfactants in the suspension show significant influence on the morphology of the particles. Unique structures, such as onion-, bud-, and pupa-like particles, can be obtained by tailoring properties of the surfactants. Both particle shape and internal structure can be reversibly tuned through pathway independent solvent vapor absorption annealing. While under strong confinement (e.g., D/L0 < 2), commensurability between D and L0 will dominate the structure of the particles. Moreover, these structured particles with cross-linkable PI domain can be selectively cross-linked and disassembled into isolated nano-objects. Janus nanodiscs with PS and P2VP chains at different sides can be obtained from pupa-like particles. Such nanodiscs can act as surfactants to stabilize oil/water emulsion droplets. This strategy, combining 3D confinement, selective cross-linking, and disassembly, is believed to be a promising approach for constructing structured particles and unique nano-objects.
Co-reporter:Shanqin Liu, Renhua Deng, Lei Shen, Xiaolin Xie, and Jintao Zhu
Macromolecules 2015 Volume 48(Issue 16) pp:5944-5950
Publication Date(Web):August 13, 2015
DOI:10.1021/acs.macromol.5b00914
Here we describe a facile yet effective route for the fabrication of crystal-like polymer microdiscs with a huge bump at the surrounding edge through hydrodynamic instabilities of emulsion droplets containing hydrophobic polymer and cosurfactant n-octadecanol (OD). This strategy allows for the generation of polymer particles with tunable size and shape by tuning the cosurfactant concentration, emulsion droplet size, and/or solvent evaporation rate. The generation of polystyrene (PS) microdiscs is balanced by the interfacial instabilities of emulsion droplets, crystallization of OD, and capillary flow. Our approach can be extended to different hydrophobic polymers and allows for the functionalization of the discs with tunable chemical/physical properties by incorporating functional species. By introducing magnetic nanoparticles, we have been able to manipulate the spatial orientation of the magnetic microdiscs via an external magnetic field. We anticipate this simple and versatile route to be useful for the design and fabrication of well-defined microparticles for potential applications in the fields of targeting, separation, sensing, drug delivery, and formation of advanced materials.
Co-reporter:Renhua Deng, Hui Li, Fuxin Liang, Jintao Zhu, Baohui Li, Xiaolin Xie, and Zhenzhong Yang
Macromolecules 2015 Volume 48(Issue 16) pp:5855-5860
Publication Date(Web):August 6, 2015
DOI:10.1021/acs.macromol.5b01261
We present with experiments and computer simulations that colloidal molecules with tunable geometry can be generated through 3D confined assembly of diblock copolymers. This unique self-assembly can be attributed to the slight solvent selectivity, nearly neutral confined interface, deformable soft confinement space, and strong confinement degree. We show that the symmetric geometry of the colloidal molecules originates from the free energy minimization. Moreover, these colloidal molecules with soft nature and directional interaction can further self-assemble into hierarchical superstructures without any modification. We anticipate that these new findings are helpful to extend the scope of our knowledge for the diblock copolymer self-assembly, and the colloidal molecules with new composition and performance will bring new opportunities to this emerging field.
Co-reporter:Xiaolu Jia, Jianying Wang, Ke Wang, and Jintao Zhu
Langmuir 2015 Volume 31(Issue 31) pp:8732-8737
Publication Date(Web):July 20, 2015
DOI:10.1021/acs.langmuir.5b02134
We present a fast and efficient strategy for the preparation of photonic hydrogels for compression and organic solvent sensing by the self-assembly of monodisperse carbon-encapsulated Fe3O4 nanoparticles (NPs). The hydrogel film was composed of acrylamide (AM) and cross-linker N,N′-methylenebis(acrylamide) (BIS), and the formed 1D NPs chain structure can be fixed within the hydrogels under a magnetic field by in situ photopolymerization. The resulting photonic hydrogels display vivid structural color which can be tuned by pressing and organic solvent treatment. The 0.2 kPa compression applied to the photonic hydrogels can be detected by the 37 nm blue shift of a reflection peak. Importantly, the photonic hydrogels can recover to their original state (<1 s) after being compressed on a pattern. Moreover, the sensitivity of mechanochromic photonic hydrogels can be adjusted by manipulating the concentration of monomers, and a large reflection peak shift (4.3 kPa, 200 nm) was observed. The detection range of the compression sensor can thus increase from 0–4.3 to 0–130.6 kPa. The photonic hydrogels are nearly monochromatic, with high sensitivity and stability and fast reversibility, and are potentially useful in displays, diagnostics, compression and solvent sensing.
Co-reporter:Jiangping Xu, Yi Yang, Ke Wang, Jingyi Li, Huamin Zhou, Xiaolin Xie, and Jintao Zhu
Langmuir 2015 Volume 31(Issue 40) pp:10975-10982
Publication Date(Web):September 20, 2015
DOI:10.1021/acs.langmuir.5b02843
Here we report the structural control of polystyrene-b-polyisoprene-b-poly(2-vinylpyridine) (PS-b-PI-b-P2VP) asymmetric ABC triblock copolymer particles under 3D confinement by tuning the interactions among blocks. The additives, including 3-n-pentadecylphenol, homopolystyrene, and solvents, which can modulate the interactions among polymer blocks, play significant roles in the particle morphology. Moreover, the structured particles can be disassembled into isolated micellar aggregates with novel morphologies or mesoporous particles with tunable pore shape. Interestingly, the formed pupa-like PS-b-PI-b-P2VP particles display interesting dynamic stretch–retraction behavior when the solvent property is changed after partial cross-linking of the P2VP block. We further prove that such dynamic behavior is closely related to the density of cross-linking. The strategies presented here are believed to be promising routes to rationally design and fabricate block copolymer particles with desirable shape and internal structure.
Co-reporter:Renhua Deng, Fuxin Liang, Xiaozhong Qu, Qian Wang, Jintao Zhu, and Zhenzhong Yang
Macromolecules 2015 Volume 48(Issue 3) pp:750-755
Publication Date(Web):January 16, 2015
DOI:10.1021/ma502339s
We present a facile and versatile approach to prepare diblock copolymer based Janus nanoparticles (NPs). Diblock copolymer PS-b-P4VP can self-assemble into patchy particles with P4VP protuberances on their surface using the emulsion solvent evaporation method. After cross-linking the P4VP protuberances, Janus NPs are produced by disassembling the particles. Within the P4VP domains, other species including metallic and inorganic are preferentially grown to extend composition and functionality. The Janus NPs are amphiphilic and capable to self-organize into superstructures. The size ratio of P4VP/PS and thus the Janus balance of the NPs are tunable by changing block chain length ratio of the block copolymers.
Co-reporter:Renhua Deng;Fuxin Liang;Peng Zhou;Chengliang Zhang;Xiaozhong Qu;Qian Wang;Jiaoli Li;Zhenzhong Yang
Advanced Materials 2014 Volume 26( Issue 26) pp:4469-4472
Publication Date(Web):
DOI:10.1002/adma.201305849
Co-reporter:Ruijing Liang, Jiangping Xu, Renhua Deng, Ke Wang, Shanqin Liu, Jingyi Li, and Jintao Zhu
ACS Macro Letters 2014 Volume 3(Issue 5) pp:486
Publication Date(Web):May 8, 2014
DOI:10.1021/mz5002146
The assembly of polystyrene (PS)-tethered gold nanoparticles (Au@PS NPs) in anodic aluminum oxide (AAO) cylindrical nanopores was investigated. This cylindrical confined assembly strategy allows us to generate novel assemblies (e.g., linear chain, zigzag, two-NP layer, three-NP layer, and hexagonally packed NP structures) by manipulating the AAO membrane pore size and molecular weight of PS ligands. Moreover, the optical property of the hybrid assemblies can be tuned through varying the interparticle distances and assembly structures. This work provides a guideline for confined assembly of functional NPs and lays groundwork for fabricating well-ordered hybrid nanostructures for optical, electronic, biosensing, and data storage devices.
Co-reporter:Weikun Li, Xiaoguang Zhu, Jianying Wang, Ruijing Liang, Jingyi Li, Shanqin Liu, Guoli Tu, Jintao Zhu
Journal of Colloid and Interface Science 2014 Volume 418() pp:81-86
Publication Date(Web):15 March 2014
DOI:10.1016/j.jcis.2013.12.004
•Instability of oil/water interfaces leads to the encapsulation of C60 into polymer micelles.•A morphological transition occurs with increasing C60 content.•Presence of C60 in micellar cores induced fluorescence quenching of P3HT.We report a facile and versatile strategy to encapsulate pristine fullerene (C60) within spherical or wormlike block copolymer micelles through interfacial instability of emulsion droplets. C60 and amphiphilic block copolymer polystyrene-b-poly(ethylene oxide) were firstly dispersed in chloroform. The resulting solution was emulsified with aqueous sodium dodecylsulfate solution by simply shaking it. The emulsion droplets were collected in an open container and the solvent was allowed to evaporate. During solvent evaporation, the emulsion droplets became unstable and broke into tiny droplets, i.e., interfacial instabilities occurred, triggering the formation of uniform spherical micelles with encapsulated fullerenes in the micellar cores. More interestingly, fullerene addition induced a morphological transition from cylindrical micelles to string-of-vesicles and then to spherical micelles with increasing fullerene contents of 5 wt%, 10 wt%, and 30 wt%, respectively. We show that the optical properties of the confined C60 molecules can be modified by varying the quantity of fullerenes in the micelles. In addition, poly(3-hexylthiophene) (P3HT) can be co-encapsulated with C60 into the micellar cores when P3HT was dissolved in the initial polymer solution prior to emulsification. Presence of C60 in the micellar cores induced fluorescence quenching of P3HT due to photoinduced energy transfer from electron-donating P3HT to electron-accepting C60 molecules. Hybrid micelles with well-controlled structures and components can be potentially useful in the area of photodynamic therapy and photovoltaics.Graphical abstractInstability of oil/water interfaces leads to kinetically trapping of pristine fullerene and/or conducting polymer into block copolymer micelles.
Co-reporter:Ruijing Liang, Liyun Dong, Renhua Deng, Jing Wang, Ke Wang, Martin Sullivan, Shanqin Liu, Jianyin Wang, Jintao Zhu, Juan Tao
European Polymer Journal 2014 Volume 57() pp:187-201
Publication Date(Web):August 2014
DOI:10.1016/j.eurpolymj.2014.05.017
•We apply SORP route to produce uniform surfactant-free biodegradable polymeric NPs.•Size and size distribution of NPs can be tuned by varying experiment conditions.•Functional species can be encapsulated to produce multifunctional NPs.•In vitro cellular uptake and cytotoxicity of different NPs are conducted.•Possible mechanism of cytotoxicity of the NPs is also investigated.Surfactant-free biodegradable polymeric nanoparticles (NPs) with uniform sizes were prepared by self-organized precipitation (SORP) method. Size and size distribution of the NPs can be easily tuned by varying the preparation conditions. More importantly, we demonstrate that hydrophobic species, semiconductor nanocrystals, and magnetic NPs can be encapsulated into the polymeric NPs effectively and quantitatively to generate multifunctional hybrid NPs. No surfactant is employed during the preparation process, which is crucial for the formed polymeric NPs to be used in bio-related applications. To evaluate the influence of surfactants on cellular behavior, cellular uptake and cytotoxicity of surfactant-free NPs and surfactant-coated NPs were performed. Our results indicated that surfactant-free NPs could be more promptly and effectively phagocytized by cells in vitro compared to residual surfactant-coated NPs prepared from the emulsion–solvent evaporation method, providing a proof that the surfactant-free NPs have more advantages in cellular uptake and more safety in drug delivery and bio-imaging. Moreover, surfactant-coated NPs inhibited cellular uptake of NPs, and had selective toxicity to melanoma A875 cells rather than human umbilical vein endothelial cells (EVC-304), especially for surfactant polyoxyethylene octyl phenyl ether (Triton X-100) due to the generation of intracellular reactive oxygen species (ROS). The surfactant-free uniform NPs prepared from SORP, combining desirable characteristics of hydrophobic drugs and functional materials, may prove advantageous in simultaneous drug delivery, imaging and magnetic field manipulation applications.
Co-reporter:Jingyi Li;Xian Li;Debin Ni;Jianying Wang;Guoli Tu
Journal of Applied Polymer Science 2014 Volume 131( Issue 23) pp:
Publication Date(Web):
DOI:10.1002/app.41186
ABSTRACT
Asymmetric block copolymer based on regioregular poly(3-hexyl thiophene) (P3HT) and poly(ethylene oxide) (PEO) was synthesized through Heck reactions. The addition of PEO block has no influence in the effective conjugation length of P3HT block and apparently provides colloidal stability for the formation of stable nanostructures. Introduction of poor solvent to good solvent containing P3HT-b-PEO will induce the crystallization-driven assembly of the P3HT into cylindrical micelles with a P3HT core, owing to π–π stacking of the conjugated backbone of P3HT. The absorption spectra of the cylindrical micelles reveal a red shift as compared to the polymer in good solvent, indicating the extension of conjugation length with an improved π–π stacking of the polymer chains within the cylindrical micelles. Our results indicated that cylindrical micelles with varied diameter and length can be obtained when solvent properties were varied using several different binary solvent mixtures. More interestingly, we demonstrate that ultrasonic processing can fragment the cylindrical micelles only when the ratio of poor solvent increases. This provides a facile and effective way to fabricate cylindrical micelles for applications in the area of polymer solar cell as well as organic optoelectronics device. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41186.
Co-reporter:Renhua Deng, Shanqin Liu, Fuxin Liang, Ke Wang, Jintao Zhu, and Zhenzhong Yang
Macromolecules 2014 Volume 47(Issue 11) pp:3701-3707
Publication Date(Web):May 30, 2014
DOI:10.1021/ma500331w
Janus colloidal particles with hierarchical structures are generated by phase separation of diblock copolymer polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) and homopolymer poly(methyl methacrylate) (PMMA) binary blends in confined geometry. The dependence of their morphology on the copolymer composition, solvent selectivity, particle size, and polymer/aqueous solution interfacial property was investigated. By varying the particle/aqueous solution interfacial property alternately, the Janus particles exhibited a reversible morphological transformation under solvent-adsorption annealing process. In addition, by introducing 3-n-pentadecyphenol (PDP) which can hydrogen bond with P4VP to form supramolecules, the structure of the Janus particles can be well tuned. Furthermore, due to the complexation of pyridine unit with Au precursor, composite Janus particles with Au nanoparticles selectively incorporated in P4VP microdomains can be easily manipulated.
Co-reporter:Jianying Wang, Weikun Li, Jintao Zhu
Polymer 2014 Volume 55(Issue 5) pp:1079-1096
Publication Date(Web):10 March 2014
DOI:10.1016/j.polymer.2014.01.027
Precise assembly and localization of preformed inorganic nanoparticles (NPs) in block copolymer (BCP) assemblies are of great importance in realizing the formation of nano-hybrids with high performance. Properties of the nanocomposites depend not only on those of individual building blocks but also on their spatial organization at different length scales, demonstrating unique optical, electrical, and magnetic properties. With the aid of the BCPs, NPs can form a broader range of structures in the nanoscopically confined geometry. Thus, many studies have focused on the selective localization of NPs in BCP aggregates. In this paper, we will outline recent advances in the preparation strategies for precise localization of inorganic NPs into BCP micelles, including co-precipitation, supramolecular assembly, interfacial instabilities of emulsion droplets, heating–cooling, electrostatic interaction, and others. Manipulating the balance between enthalpic and entropic contributions provides one of the opportunities to precisely control the spatial distribution of NPs in BCPs assemblies. We will focus on the principles of precise control of dispersion and localization of the NPs in BCP micelles. Potential applications of the hybrid micelles will finally be discussed, followed by the summary and outlook of this emerging area.Figure optionsDownload full-size imageDownload high-quality image (113 K)Download as PowerPoint slide
Co-reporter:Shanqin Liu;Mingle Cai;Renhua Deng;Jianying Wang
Korea-Australia Rheology Journal 2014 Volume 26( Issue 1) pp:63-71
Publication Date(Web):2014 February
DOI:10.1007/s13367-014-0007-3
A facile and versatile route to prepare porous polymer microparticles with tunable pore size and density through the combination of phase separation and emulsion-solvent evaporation method is demonstrated. When volatile organic solvent (e.g., chloroform) diffuses through the aqueous phase containing poly(vinyl alcohol) (PVA) and evaporates, n-hexadecane (HD) and polystyrene (PS) in oil-in-water emulsion droplets occur to phase separate due to the incompatibility between PS and HD, ultimately yielding microparticles with porous structures. Interestingly, density of the pores (pore number) on the shell of microparticles can be tailored from one to hundreds by simply varying the HD concentration and/ or the rate of solvent evaporation. Moreover, this versatile approach for preparing porous microparticles with tunable pore size and density can be applied to other types of hydrophobic polymers, organic solvents, and alkanes, which will find potential applications in the fields of pharmaceutical, catalyst carrier, separation, and diagnostics.
Co-reporter:Xiaolu Jia, Yuandu Hu, Ke Wang, Ruijing Liang, Jingyi Li, Jianying Wang, and Jintao Zhu
Langmuir 2014 Volume 30(Issue 40) pp:11883-11889
Publication Date(Web):September 18, 2014
DOI:10.1021/la502858f
We demonstrate a rapid and robust method to fabricate uniform core–shell photonic crystal (PC) microbeads by the microfluidic and centrifugation–redispersion technique. Colored crystalline colloidal arrays (CCAs) were first prepared through centrifugation–redispersion approach by self-assembly of polystyrene–poly(N-isopropylacrylamide) (PS–PNIPAm) core/shell nanoparticles (NPs). Different from the conventional NPs (e.g., charged PS or PNIPAm NPs), PS–PNIPAm NPs could easily self-assemble into well-ordered CCAs by only one purification step without laborious pretreatment (e.g., dialysis or ion exchange) or slow solvent-evaporation process. The CCAs is then encapsulated into a transparent polymer shell with functional groups (e.g., copolymer of ETPTA and butyl acrylate (BA)), triggering the formation of core–shell PC microbeads which can be used as optical encoding microcarriers. Importantly, this technique allows us to produce core–shell PC microbeads in a rapid and robust way, and the optical reflections of the PC microbeads appear highly stable to various external stimuli (e.g., temperature, pH value, and ionic strength) relying on the features of the CCAs core and protection of the polymer shell. Moreover, various probe biomolecules (e.g., proteins, antibodies, and so on) can be easily linked on the surface of the core–shell PC microbeads owing to the hydrophilic modification induced by the hydrolysis of BA on the microbead surface, enabling the multiplex biomolecular detection.
Co-reporter:Jianying Wang, Jintao Zhu
European Polymer Journal 2013 Volume 49(Issue 11) pp:3420-3433
Publication Date(Web):November 2013
DOI:10.1016/j.eurpolymj.2013.08.003
•We review recent advances in the generation of spherical photonic crystals (PCs).•Spherical PCs can be formed by confined assembly of monodisperse colloidal nanospheres in a spherical geometry.•Applications of the spherical PCs in optics are also outlined.Spherical photonic crystals (PCs), generated by assembly of monodisperse colloidal nanospheres in a spherical confined geometry, attract great attention recently owing to their potential applications in the fields of displays, sensors, optoelectronic devices, and others. Compared to their conventional film or bulk counterparts, the optical stop band of the spherical PCs is independent of the rotation under illumination of the surface of a fixed incident angle of the light, broadening their applications. In this paper, we will review recent advances in the field of spherical PCs including design, preparation and potential applications. Various preparation strategies for spherical PCs, including solvent-evaporation induced crystallization method, microfluidic-assisted approach, and others are outlined. Their applications based on the unique optical properties (such as photonic band gaps and structural colors) for sensing and displaying are then presented, followed by the perspective of this emerging field.Graphical abstract
Co-reporter:Nan Cao, Shanqin Liu, Min Wu, Renhua Deng, Jianying Wang, Zhiping Zhang, Jintao Zhu
European Polymer Journal 2013 Volume 49(Issue 11) pp:3691-3701
Publication Date(Web):November 2013
DOI:10.1016/j.eurpolymj.2013.07.037
•We introduce a facile route to synthesize ball-like polymer–inorganic patchy microcapsyles.•Sol–gel chemistry and phase separation were combined to generate the patchy capsules.•Patch size and shape can be tuned by tailoring the experimental parameters.We introduce a facile and versatile approach for the formation of ball-like polymer–inorganic patchy microcapsules with a tunable shell by combining sol–gel chemistry of silica precursor and phase separation between the polymer and the precursor. Firstly, chloroform-in-water emulsion droplets containing poly(methyl methacrylate) (PMMA), silica precursor [tetraethyl orthosilicate (TEOS)] and co-surfactant sodium dioctyl sulfosuccinate (Aerosol OT or AOT) were prepared by shaking the mixture by hand. Due to the added AOT, water molecules diffuse into the chloroform droplets, and the tiny water droplets would coalesce gradually, triggering the formation of double emulsion droplets. Upon further solvent evaporation, the concentration of the polymer and the silica precursor in the oil shell of the double emulsions increases, leading to the phase separation between the polymer and the precursors (and partially formed silica through the hydrolysis and condensation of TEOS). Because of the confined geometry of the oil shell in the double emulsions, polymeric disc-like structures, stabilized by AOT, were dispersed in the silica precursors. Meanwhile, the silica precursor hydrolyzed and condensed when brought in contact with the aqueous solution, ultimately leading to the formation of a mineralized shell around the polymer domains and the hybrid patchy microcapsules. Effect of synthesis conditions, such as the amount of TEOS, AOT, and PMMA used, the pH value, and solvent evaporation rate on interfacial behavior of the solvent/water; and the morphology of the patchy microcapsules were investigated. Patchy microcapsules with tunable patch size and shape can be generated through tailoring the experimental parameters. Our study indicates that the hybrid patchy microcapsules can be formed by taking advantage of the sol–gel chemistry and the phase separation process, and the underlying generality of the synthesis procedure allows for a variety of applications, including drug storage, coatings, delivery, catalysis, and smart building blocks in self-assembling systems.Graphical abstract
Co-reporter:Weikun Li, Shanqin Liu, Renhua Deng, Jianying Wang, Zhihong Nie, and Jintao Zhu
Macromolecules 2013 Volume 46(Issue 6) pp:2282-2291
Publication Date(Web):March 12, 2013
DOI:10.1021/ma302515p
The formation of well-defined polymer/inorganic nanoparticles (NPs) hybrid micelles with high loading of the NPs is critical to the development of nanomaterials with desired optical, electric, magnetic, and mechanical properties. Herein, we introduce a simple strategy to encapsulate monodisperse polystyrene (PS)-grafted Au NPs into the PS core of PS-b-poly(4-vinylpyridine) (PS-b-PVP) micelles through block copolymer (BCP)-based supramolecular assembly. We demonstrate that selective incorporation of gold NPs into the PS cores during the assembly process can induce the formation of well-ordered hybrid micelles with spherical, cylindrical, or nanosheet morphologies. The number of NPs in each micelle can be effectively increased by simply increasing the content of NPs and adjusting the ratio of 3-n-pentadecylphenol (PDP) to the P4VP units accordingly. The balance between the NP loading (increasing the volume fraction of PS domain) and the PDP addition (increasing the volume fraction of PVP(PDP) domain) maintains the same micellar morphology while achieving high NP loading. Moreover, strong enthalphic attraction of H-bonding between PDP and P4VP can increase the effective interaction parameter of the system to maintain the strong segregation, leading to the formation of ordered structures. The mass density of NPs in the hybrid micelles was further enhanced after removal of the added PDP from the supramolecules. No macrophase separation or order–order morphological transition was observed even when the volume fraction of PS-grafted NPs (φNP-M) in the hybrid micelles reached 84.1 vol % (or 68 wt % on the ligand free NPs basis). Furthermore, we show that ordered clusters of NPs were generated within the spherical micelles when the φNP-M reached 72.5 vol %. This directed supramolecular assembly provides an easy means to tailor the interactions between BCPs and NPs, thus generating ordered structures which can only be achieved when the loading of NPs is high enough. This approach is versatile and applicable to different types of NPs and different micellar aggregates and supramolecular pairs. It offers a new route for preparing hybrids with applications in the fields of molecular electronic devices, high-density data storage, nanomedicine, and biosensors.
Co-reporter:Weikun Li, Peng Zhang, Ming Dai, Jie He, Taarika Babu, Ye-Long Xu, Renhua Deng, Ruijing Liang, Ming-Hui Lu, Zhihong Nie, and Jintao Zhu
Macromolecules 2013 Volume 46(Issue 6) pp:2241-2248
Publication Date(Web):March 5, 2013
DOI:10.1021/ma400115z
This paper describes an effective approach to order gold nanorods (NRs) within cylindrically confined microdomains of block copolymer- (BCP-) based supramolecular assemblies. Individual BCP micelles encapsulated with well-ordered NRs can be obtained by disassembling the supramolecular structures. The mismatch of binary polymer brushes with different lengths on the surface of the NRs was used to effectively improve the dispersion of the NRs within polymer matrix, due to enhanced wetting of the brushes by surrounding mismatch polymers. This enables us to quantitatively explore the location and orientation of the NRs within confined geometries. By varying the content of NRs, the aspect ratio of the NRs, or the diameter of the cylindrical BCP micelles, the orientation of the NRs within micelles can be tuned to form one-dimensional nanostrings with end-to-end organization of NRs along the micelles or with side-by-side twisted arrangement of NRs perpendicular to the micelles. UV–vis spectroscopy measurements and finite-difference time-domain (FDTD) calculations confirm that our approach provides a simple yet versatile route to tune the optical properties of the hybrid micelles by controlling the ordering of the NRs. This work provides guidelines for dispersing other functional anisotropic NPs, and lays groundwork for the fabrication of optical and electronic devices.
Co-reporter:Renhua Deng, Fuxin Liang, Weikun Li, Zhenzhong Yang, and Jintao Zhu
Macromolecules 2013 Volume 46(Issue 17) pp:
Publication Date(Web):August 29, 2013
DOI:10.1021/ma401398h
A reversible transformation of overall shape and internal structure as well as surface composition of nanostructured block copolymer particles is demonstrated by solvent-adsorption annealing. Polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) pupa-like particles with PS and P4VP lamellar domains alternatively stacked can be obtained by self-assembly of the block copolymer under 3D soft confinement. Chloroform, a good solvent for both blocks, is selected to swell and anneal the pupa-like particles suspended in aqueous media. Reversible transformation between pupa-like and onion-like structures of the particles can be readily tuned by simply adjusting the particle/aqueous solution interfacial property. Interestingly, poly(vinyl alcohol) (PVA) concentration in the aqueous media plays a critical role in determining the particle morphology. High level of PVA concentration is favorable for pupa-like morphology, while extremely low concentration of PVA is favorable for the formation of onion-like particles. Moreover, the stimuli-response behavior of the particles can be highly suppressed through selective growth of Au nanoparticles within the P4VP domains. This strategy provides a new concept for the reversible transformation of nanostructured polymer particles, which will find potential applications in the field of sensing, detection, optical devices, drug delivery, and smart materials fabrication.
Co-reporter:Jianying Wang, Yuandu Hu, Renhua Deng, Ruijing Liang, Weikun Li, Shanqin Liu, and Jintao Zhu
Langmuir 2013 Volume 29(Issue 28) pp:8825-8834
Publication Date(Web):2017-2-22
DOI:10.1021/la401540s
Hydrogel photonic crystal microparticles (HPCMs) with inverse-opal structure are generated through a combination of microfluidic and templating technique. Temperature and pH responsive HPCMs have firstly been prepared by copolymerizing functional monomers, for example, N-isopropylacrylamide (NIPAm) and methacrylic acid (MAA). HPCMs not only show tunable color variation almost covering the entire wavelength of visible light (above 150 nm of stop-band shift) by simply tailoring temperature or pH value of the solution, but also display rapid response (less than 1 min) due to the small volume and well-ordered porous structure. Importantly, the temperature sensing window of the HPCMs can be enlarged by controlling the transition temperature of the hydrogel matrix, and the HPCMs also exhibit good reversibility and reproducibility for pH response. Moreover, functional species or particles (such as azobenzene derivative or magnetic nanoparticles) can be further introduced into the hydrogel matrix by using post-treatment process. These functionalized HPCMs can respond to the UV/visible light without significantly influencing the temperature and pH response, and thus, multiresponsive capability within one single particle can be realized. The presence of magnetic nanoparticles may facilitate secondary assembly, which has potential applications in advanced optical devices.
Co-reporter:Yuandu Hu, Jianying Wang, Chengnian Li, Qin Wang, Hong Wang, Jintao Zhu, and Yajiang Yang
Langmuir 2013 Volume 29(Issue 50) pp:15529-15534
Publication Date(Web):2017-2-22
DOI:10.1021/la404082y
A new strategy to prepare core/shell Janus photonic crystal (PC) microspheres with reversible optical spectrum property is demonstrated. The microfluidic technique was employed to generate the uniform core/shell PC microspheres containing nanogels aqueous suspension. Under centrifugal force, the nanogel particles homogeneously dispersed in the core of microspheres would aggregate in the half of the microspheres, leading to Janus PC microspheres with varied reflection spectra at the different side of the spheres. More interestingly, such Janus structure of PC microspheres and their reflection spectrum were significantly reversible when the centrifugation was employed and removed alternatively. In addition, due to the soft and thermal-responsive nature of the building blocks (e.g., nanogels), Janus structures and optical properties of the PC microspheres are highly influenced by the temperature, centrifugal speed, and time, providing the other parameters on the manipulation of properties of the PC microspheres. This strategy provides a new concept for the preparation of Janus PC microspheres with tunable structures and optical properties, which will find potential applications in the field of sensors, optical devices, barcodes, etc.
Co-reporter:Renhua Deng;Shanqin Liu;Jingyi Li;Yonggui Liao;Juan Tao
Advanced Materials 2012 Volume 24( Issue 14) pp:1889-1893
Publication Date(Web):
DOI:10.1002/adma.201200102
Co-reporter:Shanqin Liu;Renhua Deng;Weikun Li
Advanced Functional Materials 2012 Volume 22( Issue 8) pp:1692-1697
Publication Date(Web):
DOI:10.1002/adfm.201103018
Abstract
A general and versatile route to prepare hierarchical polymer microparticles via interfacial instabilities of emulsion droplets is demonstrated. Uniform emulsion droplets containing hydrophobic polymers and n-hexadecanol (HD) are generated through microfluidic devices. When organic solvent diffuses through the aqueous phase and evaporates, shrinking emulsion droplets containing HD and polystyrene (PS) will trigger interfacial instabilities to form microparticles with wrinkled surfaces. Interestingly, surface-textures of the particles can be accurately tailored from smooth to high textures by varying the HD concentration and/or the rate of solvent evaporation. Moreover, composite particles can be generated by suspending different hydrophobic species to the initial polymer solutions. This versatile approach for preparing particles with highly textured surfaces can be extended to other type of hydrophobic polymers which will find potential applications in the fields of drug delivery, tissue engineering, catalysis, coating, and device fabrication.
Co-reporter:Shanqin Liu;Renhua Deng;Weikun Li
Advanced Functional Materials 2012 Volume 22( Issue 8) pp:
Publication Date(Web):
DOI:10.1002/adfm.201290047
Co-reporter:Jianying Wang, Yuandu Hu, Renhua Deng, Wenjing Xu, Shanqin Liu, Ruijing Liang, Zhihong Nie and Jintao Zhu
Lab on a Chip 2012 vol. 12(Issue 16) pp:2795-2798
Publication Date(Web):30 May 2012
DOI:10.1039/C2LC40419B
Holey photonic crystal (PC) microcapsules are generated through a combined technique of microfluidic- and controlled-photopolymerization. This versatile route allows the fine tuning of shell structure (from well-ordered nanoporous to single-hole structures with tailored hole size) by etching or by varying UV light intensity, and endowing the PC microcapsules with multifunctional properties.
Co-reporter:Naixiang Wang, Yonggui Liao, Renhua Deng, Shanqin Liu, Nan Cao, Bien Tan, Jintao Zhu and Xiaolin Xie
Soft Matter 2012 vol. 8(Issue 9) pp:2697-2704
Publication Date(Web):25 Jan 2012
DOI:10.1039/C2SM06874E
We introduce a facile, yet robust route for fabricating polymer–inorganic hybrid microparticles with hierarchically-structured morphologies by taking advantage of the interfacial instabilities of emulsion droplets and the sol–gel chemistry of silica precursors. In general, chloroform-in-water emulsion droplets containing an amphiphilic diblock copolymer [polystyrene-b-poly (ethylene oxide) (PS–PEO)] and metal oxide precursors [tetraethyl orthosilicate (TEOS) or mixtures of TEOS and tetra-tert-butyl orthotitanate (TBOT)] were prepared by shaking. Upon solvent evaporation, interfacial instabilities occurred while the inorganic precursors started to hydrolyze and condense when brought in contact with the aqueous solution, ultimately leading to the formation of a mineralized shell at the oil–water interface and hybrid microparticles. By varying the rate of solvent evaporation, qualitatively different mechanisms of the instabilities (e.g., the budding of vesicles or a spines-to-vesicles transition) were observed. The effect of the synthesis conditions, such as the amount of TEOS, the solvent evaporation rate, and the pH value on the self-assembly of the copolymer, the interfacial behavior of the solvent/water, and the morphology of the microparticles were investigated. Hierarchical microparticles with different morphologies, ranging from cage-like, honeycomb-like, dendritic, to budded microparticles, were prepared by combining the sol–gel process with the self-assembly of the polymers in the emulsion droplets. Moreover, the intermediate structures of the instabilities were kinetically trapped by the mineralization process. Our study indicated that the hybrid microparticles formed by interfacial instabilities of emulsion droplets can significantly expand the range of accessible morphologies, which provides the potential for advanced applications in drug storage, coatings, controlled release, and catalysis.
Co-reporter:Jintao Zhu, Ryan C. Hayward
Journal of Colloid and Interface Science 2012 Volume 365(Issue 1) pp:275-279
Publication Date(Web):1 January 2012
DOI:10.1016/j.jcis.2011.09.020
Evaporating droplets of volatile organic solvent containing amphiphilic block copolymers may undergo hydrodynamic instabilities that lead to dispersal of copolymer micelles into the surrounding aqueous phase. As for related phenomena in reactive polymer blends and oil/water/surfactant systems, this process has been ascribed to a nearly vanishing or transiently negative interfacial tension between the water and solvent phases induced by adsorption of copolymer to the interface. In this report, we investigate the influence of the choice of organic solvent and polymer composition for a series of polystyrene-b-poly(ethylene oxide) (PS–PEO) diblock copolymers, by in situ micropipette tensiometry on evaporating emulsion drops. These measurements suggest that the sensitivity to the organic solvent chosen reflects both differences in the bare solvent/water interfacial tension as well as the propensity of the copolymer to aggregate within the organic phase. While instabilities coincident with an approach of the interfacial tension nearly to zero were observed only for copolymers with PEO content greater than 15 wt.%, beyond this point the interfacial behavior and critical concentration needed to trigger surface instability were found to depend only weakly on copolymer composition.Graphical abstractNearly vanishing oil/water interfacial tensions induced by amphiphilic diblock copolymers drive interfacial instabilities and lead to dispersal of block copolymer micelles in water.Highlights► Micropipette tensiometry to characterize interfacial behavior of amphiphilic copolymers within evaporating emulsion droplets. ► Instabilities coincident with an approach of interfacial tension nearly to zero. ► Interfacial tension and instabilities depend on solvent type and polymer composition.
Co-reporter:Wenjing Xu, Xi Yu, Ruijing Liang, Shanqin Liu, Qianwei Tian, Renhua Deng, Jintao Zhu
Materials Letters 2012 Volume 77() pp:96-99
Publication Date(Web):15 June 2012
DOI:10.1016/j.matlet.2012.03.004
We describe a simple, effective concept for the fabrication of nanocapsules by combining membrane extrusion and self-emulsification approach. Uniform emulsion droplets containing polymers were firstly prepared through the extrusion strategy, and relatively uniform nanocapsules can thus be generated after complete removal of the organic solvent. Size and size distribution of the capsules can be easily tuned through varying initial polymer concentration and extrusion pass times. This facile approach can be extended to generate different biodegradable polymer nanocapsules which will find applications in the fields of drug delivery, bioimaging, and diagnostics.Highlights► Membrane extrusion technique was used to produce uniform emulsion droplets. ► Nanocapsules generation by combining extrusion and self-emulsification. ► Size/size distribution of the nanocapsules can be tailored through our approach.
Co-reporter:Yuandu Hu, Jianying Wang, Hong Wang, Qin Wang, Jintao Zhu, and Yajiang Yang
Langmuir 2012 Volume 28(Issue 49) pp:17186-17192
Publication Date(Web):November 15, 2012
DOI:10.1021/la304058j
Soft photonic crystals (PC) are more appealing due to the responsiveness of the building blocking-deformable nanoparticles to the external stimuli. In this report, we demonstrate, for the first time, the generation of soft core/shell PC microspheres through a combination of a microfluidic technique, encapsulation of well-ordered temperature responsive polymer nanogels suspension, and photopolymerization of a transparent shell resin. This strategy not only ensures the monodispersity of core/shell PC microspheres, but also precisely controls their size, shell thickness, and optical properties by simply adjusting the flow rate ratio and mass fraction of the nanogels. More interestingly, the intensity of the reflection spectra of the crystalline nanogel arrays in the core can be modulated reversibly by controlling the shell thickness or the temperature. As a result of their symmetric structure, the resulting PC microspheres exhibited excellent structural colors and photonic band gaps for normal incident light independent of the position on the spherical surface. Multifunctional PC microspheres can also be generated by simply dispersing functional species together with the nanogels. This core/shell PC microsphere with tunable shell thickness and reversible thermoresponse could be significant for potential applications in the fields of chemical/biological sensors, display, encoding, and optical switching.
Co-reporter:Xi Yu, Ziliang Zhao, Wei Nie, Renhua Deng, Shanqin Liu, Ruijing Liang, Jintao Zhu, and Xiangling Ji
Langmuir 2011 Volume 27(Issue 16) pp:10265-10273
Publication Date(Web):July 18, 2011
DOI:10.1021/la201944s
A detailed study on the direct synthesis of biocompatible polyesters (e.g., PLA, PLGA or PCL) microcapsules and multifunctional microcapsules, which does not require any template and core removal, is presented. The technique is based on the modified self-emulsification process within the emulsion droplets by simply adding sodium dioctyl sulfosuccinate (Aerosol OT or AOT) as a cosurfactant to the initial polymer solution, followed by double emulsion formation due to the coalescence of the internal water droplets. Microcapsules with tunable sizes (ranging from hundreds of nanometers to tens of micrometers) and morphologies were then obtained through solidification of droplet shell of the double emulsion via solvent removal. In this report, we have systematically investigated the effect of experimental parameters, such as polymer and AOT concentration, polymer molecular weight on the double emulsion formation process, and the final morphologies of the microcapsules. We demonstrate that the capsules can encapsulate either hydrophobic or hydrophilic dyes during solvent evaporation. Dye-release studies show a correlation between shell thickness, capsules size, and diffusive release rate, providing insights into the shell formation and shell thickness processing. Moreover, hydrophobic nanoparticles, such as oleic-acid coated Fe3O4 nanoparticles and quantum dots, can also be incorporated into the walls of the microcapsules. Such functional microcapsules might find applications in the fields of controlled release, bioimaging, diagnostics, and targeting.
Co-reporter:Weikun Li;Shanqin Liu;Renhua Deng ; Jintao Zhu
Angewandte Chemie 2011 Volume 123( Issue 26) pp:5987-5990
Publication Date(Web):
DOI:10.1002/ange.201008224
Co-reporter:Weikun Li;Shanqin Liu;Renhua Deng ; Jintao Zhu
Angewandte Chemie International Edition 2011 Volume 50( Issue 26) pp:5865-5868
Publication Date(Web):
DOI:10.1002/anie.201008224
Co-reporter:ME Peterson;GJ Colurso;NS Halmi;AS Liotta;DT Krieger
Science 1981 Volume 211(Issue 4477) pp:72-74
Publication Date(Web):02 Jan 1981
DOI:10.1126/science.6255564
Abstract
The pituitary intermediate lobe of most species is cytologically monotonous, but that of the dog is composed of two immunocytochemically distinct cell types. The predominant A cells are typical pars intermedia cells: they stain immunocytochemically for alpha-melanotropin and, more weakly, for adrenocorticotropin and beta-lipotropin. The B cells are like the corticotrophs of the anterior lobe: they stain intensely for adrenocorticotropin and beta-lipotropin but not for alpha-melanotropin. The B cells may account for the high concentration of bioactive adrenocorticotropin measured in the canine pars intermedia, and may explain why in dogs adenomas causing Cushing's disease through hypersecretion of adrenocorticotropin can arise from the intermediate as well as the anterior pituitary lobe.
Co-reporter:Jun Li, Yujue Wang, Ruijing Liang, Xiangjie An, Ke Wang, Guanxin Shen, Yating Tu, Jintao Zhu, Juan Tao
Nanomedicine: Nanotechnology, Biology and Medicine (April 2015) Volume 11(Issue 3) pp:769-794
Publication Date(Web):1 April 2015
DOI:10.1016/j.nano.2014.11.006
Melanoma is one of the most aggressive skin cancers, notorious for its high multidrug resistance and low survival rate. Conventional therapies (e.g., dacarbazine, interferon-alpha-2b and interleukin-2) are limited by low response rate and demonstrate no overall survival benefit. Novel targeted therapies (e.g., vemurafenib, dabrafenib and trametinib) have higher initial response rate and clear impact on the overall survival, but relapse usually occurs within 6 to 9 months. Although immunotherapy (e.g., ipilimumab, pembrolizumab and nivolumab) can achieve long-term and durable response, rate of adverse events is extremely high. With the development of nanotechnology, the applications of nanocarriers are widely expected to change the landscape of melanoma therapy for foreseeable future. In this review, we will relate recent advances in the application of multifunctional nanocarriers for targeted drug delivery to melanoma, in melanoma nanotheranostics and combination therapy, and nanopharmaceutical associated melanoma clinical trials, followed by challenges and perspectives.From the Clinical EditorThe team of authors describes the current treatment regimes of malignant melanoma emphasizing the importance of achieving a better efficacy and the need to develop a better understanding of melanoma tumorigenesis.Due to its high multidrug resistance and low survival rate, melanoma is one of the most aggressive skin cancers. Fortunately, the applications of nanocarriers are widely expected to change the landscape of melanoma therapy for foreseeable future. We will demonstrate recent development in the application of multifunctional nanoparticles for targeted drug delivery (active and passive targeting) to melanoma, in melanoma nanotheranostics and combination therapy, and nanopharmaceutical associated melanoma clinical trials. Moreover, we will discuss current status, challenges, and perspectives of the targeted NPs drug delivery to melanoma.Download high-res image (217KB)Download full-size image
Co-reporter:Jiangping Xu, Yi Yang, Ke Wang, Yuqing Wu and Jintao Zhu
Inorganic Chemistry Frontiers 2017 - vol. 1(Issue 3) pp:NaN511-511
Publication Date(Web):2016/09/05
DOI:10.1039/C6QM00072J
In this communication, we report a facile yet effective approach to fabricate polystyrene-b-poly(4-vinyl pyridine) (PS-b-P4VP) convex lens (CL)-like microparticles with hexagonally stacked cylindrical P4VP domains via three-dimensional confined assembly. Addition of a hydrogen bonding agent, 3-n-pentadecylphenol (PDP), not only changes the volume fraction of the P4VP domain, but also alters the interfacial interactions between the blocks and the surfactant. A neutral interface could be created by tuning the content of PDP, resulting in the formation of CL-like microparticles. Selective swelling and then deswelling of these particles offers us a convenient way to synthesize isoporous particles with tunable pore size, potentially useful in ultrafiltration with high selectivity.
Co-reporter:Lei Shen, Jun Xie, Juan Tao and Jintao Zhu
Journal of Materials Chemistry A 2015 - vol. 3(Issue 6) pp:NaN1162-1162
Publication Date(Web):2014/12/09
DOI:10.1039/C4TB01905A
We develop a novel heterogeneous pattern with nanometer-sized spots surrounded with a bio-inert matrix by using a diblock copolymer thin film. The nanopattern with features down to 20 nm is highly resistant to protein adsorption and cell adhesion. By providing a domelike topography similar to biologically relevant size, such a heterogeneous nanopattern demonstrates an excellent anti-biofouling property to control protein–surface and cell–surface interactions at the molecular level.
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