Xia Han

Name: 韩霞; Han, Xia

Organization: East China University of Science and Technology , China

Department: Department of Chemistry

Title: Associate Professor(PhD)

Chemicals
References

Dual Thermoresponsive Aggregation of Schizophrenic PDMAEMA-b-PSBMA Copolymer with an Unrepeatable pH Response and a Recycled CO2/N2 Response

Co-reporter:Hui Sun, Xiaolu Chen, Xia Han, and Honglai Liu

Langmuir March 14, 2017 Volume 33(Issue 10) pp:2646-2646

Publication Date(Web):February 23, 2017

DOI:10.1021/acs.langmuir.7b00065

A dual thermoresponsive block copolymer of poly[2-(dimethylamino)ethyl methacrylate]-block-poly(sulfobetaine methacrylate) (PDMAEMA-b-PSBMA) exhibited reversible schizophrenic aggregation behavior in water because of the upper critical solution temperature (UCST) of the PSBMA block and the lower critical solution temperature (LCST) of the PDMAEMA block. Both the UCST and LCST shifted to lower values with increasing DMAEMA/SBMA block ratios, which was ascribed to the hydrophobic/hydrophilic balance of both blocks. Because of the salt-sensitive PSBMA and pH-responsive PDMAEMA, the UCST and LCST values of PDMAEMA-b-PSBMA were codetermined by varying the salt concentrations and pH. Specifically, increasing the salt concentration resulted in a notable decrease in the UCST and a slight increase in the LCST due to the salt-induced screening of the electrostatic attractions of the PSBMA and salt-enhanced solubility of the PSBMA blocks, respectively. The LCST decreased with increasing pH because of the deprotonation of PDMAEMA, and the UCST first increased and then decreased with increasing pH. Besides, the copolymer with larger PDMAEMA content was more sensitive to pH. For the repetitive adjustment to thermoresponsive aggregation, repeated addition of acids and bases induced salt accumulation and diminished the switchability of pH, whereas repeated switching cycles were achieved by CO2/N2 bubbling without introducing salt enrichment. The difference in HCl/NaOH titration and CO2/N2 bubbling also existed in the switching cycles when PDMAEMA-b-PSBMA served as a stimulus-responsive emulsifier.

Microscopic insight into the DNA condensation process of a zwitterion-functionalized polycation

Co-reporter:Hui Sun;Li Zhou;Xiaolu Chen;Rui Wang;Honglai Liu

Biopolymers 2016 Volume 105( Issue 11) pp:802-810

Publication Date(Web):

DOI:10.1002/bip.22910

Abstract

Zwitterion-functionalized polycations are ideal gene carriers with long circulation, high cellular uptaking and low cell viability. However, the trade-off between the DNA condensation efficiency and the cell viability must be addressed. The purpose of this study is to provide a microscopic insight into the DNA condensation process and to explore the effect of a zwitterionic block of zwitterion-functionalized polycation, which is of great significance in designing novel gene delivery systems. Poly[2-(dimethylamino)ethyl methacrylate-b-(sulfobetaine methacrylate)] (PDMAEMA-b-PSBMA) copolymers were synthesized and used as the model systems. Different from the conventional concept that the PSBMA zwitterionic block act only as the “stealthy” groups, the subtle differences in physical and colloidal characteristics between the polycation/DNA polyplexes show that the PSBMA segment is capable of wrapping DNA attributed to the quaternary ammonium cations, without compromising the DNA condensation capability. On the other hand, the incorporation of PSBMA block reduces the surface charge of the polyplexes, which substantially result in the inefficient transfection and the reduced cytotoxicity.

Coarse-Grained Simulation of Polycation/DNA-Like Complexes: Role of Neutral Block

Co-reporter:Bicai Zhan, Kaihang Shi, Zhexi Dong, Wenjie Lv, Shuangliang Zhao, Xia Han, Hualin Wang, and Honglai Liu

Molecular Pharmaceutics 2015 Volume 12(Issue 8) pp:2834-2844

Publication Date(Web):June 15, 2015

DOI:10.1021/mp500861c

Complexes formed by polycations and DNA are of great research interest because of their prospective application in gene therapy. Whereas the applications of multiblock based polycation generally exhibit promising features, a thorough understanding on the effect of neutral block incorporated in polycation is still lacking. By using coarse-grained dynamics simulation with the help of a simple model for solvent mediated interaction, we perform a theoretical study on the physicochemical properties of various polyplexes composed of a single DNA-like polyanion chain and numbers of linear polycationic chains with different modifications. By analyzing various properties, we find the hydrophobic/hydrophilic modifications of linear polycations may bring an improvement on one aspect of the properties as gene carrier but also involve a trade-off with another one. In particular, polycation with a hydrophobic middle block and a hydrophilic tail block display distinct advantages among di- and triblock linear polycations as gene carrier, while careful design of the hydrophobic block should be made to reduce the zeta potential. The simulation results are compared with available experimental data displaying good agreements.

From multi-responsive tri- and diblock copolymers to diblock-copolymer-decorated gold nanoparticles: the effect of architecture on micellization behaviors in aqueous solutions

Co-reporter:Lichun Song, Hui Sun, Xiaolu Chen, Xia Han and Honglai Liu

Soft Matter 2015 vol. 11(Issue 24) pp:4830-4839

Publication Date(Web):12 May 2015

DOI:10.1039/C5SM00859J

This work reports on the aqueous stimuli-responsive behaviors of an ABA triblock copolymer, a BAB triblock copolymer, an AB diblock copolymer and citrate-based gold nanoparticles decorated with AB diblock copolymers (where A is the pH- and thermo-responsive poly[N,N-(dimethylamino)ethyl methacrylate] (PDMAEMA) and B is the thermo-responsive poly[2-(2-methoxyethoxy)ethyl methacrylate] (PMEO2MA)). The symmetric triblock polymers were synthesized via sequential atom transfer radical polymerization (ATRP) using a disulfide-functionalized initiator. Subsequently, the thiol-ended diblock copolymers were facilely obtained by reducing these triblock copolymers and were grafted onto gold nanoparticle (AuNP) surfaces via ligand exchange to yield stimuli-sensitive gold nanoparticles (Au@AB and Au@BA). The ABA and BAB triblock copolymers exhibited two-step thermo-induced aggregation behavior in water at a pH near the isoelectric point (IEP), which resulted in the formation of micelles after the first lower critical solution temperature (LCST) and large aggregates consisting of clustered micelles above the second LCST transition. The significant difference between the micelle sizes of the ABA and BAB copolymers, such that the micelle size of the BAB copolymer was smaller than that of the ABA copolymer although both had a similar unit composition, suggests a distinction between the micelle structures. The “branch” and “flower-like” micelles that are formed in the ABA and BAB aqueous solutions, respectively, ultimately governed the phase transition behaviors. The AB diblock copolymer exhibited similar micellization behavior and a micelle size roughly similar to that of the ABA triblock copolymer, although the chain length of the AB copolymer is only half that of the ABA copolymer. Both Au@PDMAEMA–PMEO2MA and Au@PMEO2MA–PDMAEMA showed similar dual LCST behaviors and pH-responsive behaviors in aqueous solutions without the addition of salt. A significant difference was observed between the two types of hybrid AuNPs in salty solutions, in which only the Au@PDMAEMA–PMEO2MA system exhibited thermo-induced aggregation behavior. These hybrid nanoparticles can be used as phase transfer reagents. Additionally, AuNPs capped with PDMAEMA–PMEO2MA diblock copolymer can spontaneously transfer across a water–toluene interface.

pH-modulated double LCST behaviors with diverse aggregation processes of random-copolymer grafted silica nanoparticles in aqueous solution

Co-reporter:Xiaolu Chen, Hui Sun, Jian Xu, Xia Han, Honglai Liu and Ying Hu

RSC Advances 2015 vol. 5(Issue 105) pp:86584-86592

Publication Date(Web):07 Oct 2015

DOI:10.1039/C5RA13557E

Thermo-responsive hybrid nanoparticles composed of silica-core and poly(N,N-dimethylaminoethyl methacrylate-co-N-isopropylacrylamide) P(DMAEMA-co-NIPAM) copolymer-shell were prepared through a one-pot surface-initiated atom transfer radical polymerization (ATRP) technique. The well-defined core–shell hybrid nanoparticles with copolymer shell of uniform thickness were revealed by transmission electron microscopy (TEM). The thermo-responsive behavior of the hybrid nanoparticles in aqueous solutions was evaluated through combined techniques, including ultraviolet-visible spectrophotometer (UV-vis) and dynamic light scattering (DLS) analysis. Interestingly, pH-modulated LCST behavior with diverse aggregation processes can be observed. Specifically, the random copolymer grafted nanoparticles presented an LCST behavior with one-step transition process of shrink in acidic solution, a double LCST behavior with three-step transition process of shrink–shrink–aggregation in neutral solution, and a double LCST behavior with two-step transition process of assembly-shrink/aggregation in basic solution. The difference was attributed to the pH-modulated imbalances of electrostatic repulsion and hydrophobic interaction of the attached copolymer chains. Overall, these results disclose that pH and temperature can act as efficient modulators for the programmable control and fine-tuning of the morphology and aggregate size of the core–shell functionalized nanoparticles.

A lattice molecular thermodynamic model for thermo-sensitive random copolymer hydrogels

Co-reporter:Cheng Lian;Dongyan Zhi;Shuangliang Zhao

Colloid and Polymer Science 2015 Volume 293( Issue 2) pp:433-439

Publication Date(Web):2015 February

DOI:10.1007/s00396-014-3411-9

Recent advances in polymer chemistry have enabled the design of a wide range of copolymer hydrogels consisting of stimulus-responsive blocks and other functional blocks used in many fields. In this work, a new molecular thermodynamic model is developed based on our previous work for the swelling behavior of temperature-sensitive random copolymer hydrogels. The influences of polymer species, the molar fraction f, and the cross-linking degree on the swelling behaviors of copolymer hydrogels are investigated. The calculated swelling curves of PNIPAm-ENAG copolymer hydrogels have been compared with the corresponding experimental results. It is shown that the results obtained by model are quite consistent with the experimental data, and this indicates the validity of our model.

Controlled assembly of plasmonic nanoparticles using neutral-charged diblock copolymers

Co-reporter:Quanyi Yin, Xia Han, Virginie Ponsinet, Honglai Liu

Journal of Colloid and Interface Science 2014 Volume 431() pp:97-104

Publication Date(Web):1 October 2014

DOI:10.1016/j.jcis.2014.05.047

•Plasmonic nanoparticle assemblies are induced using electrostatic complexation.•The complex formation is triggered by a change in ionic strength.•Quantities of polymer and nanoparticles in the suspension tune the complex size.•The complex formation is reversible and complete.In this study, our aim was to control the assembly of plasmonic nanoparticles by using the electrostatic assembly of oppositely charged colloidal species. Gold nanoparticles (Au NPs) were modified with a carboxyl-terminated polymeric ligand, O-(2-carboxyethyl)-O′-(2-mercaptoethyl) heptaethylene glycol (SH-PEG7-COOH), so that they are negatively charged on the pH range 5–10 and they stand elevated ionic strength (up to 1 M NaCl) without loss of colloidal stability. Block copolymers poly[(ethylene glycol) methyl ether-block-(N,N-dimethylamino-2-ethyl methacrylate)] (mPEG–PDMAEMA), with a neutral mPEG block and a pH-sensitive positively charged PDMAEMA block were synthesized by atom transfer radical polymerization (ATRP). The formation of complexes, driven by the electrostatic attraction between opposite charges and by the release of the condensed counter ions, was investigated using dynamic light scattering and spectrophotometry. The relative quantities of polymer chains and nanoparticles in the suspension were shown to affect the size of the formed complexes. In this report, it is also shown that the complex formation is reversible. Stable complexes of typical size 400 nm were formed, which could be used as building blocks for new optical materials.

Dual-stimuli responsive behaviors of diblock polyampholyte PDMAEMA-b-PAA in aqueous solution

Co-reporter:Zhiying Xiong, Baoliang Peng, Xia Han, Changjun Peng, Honglai Liu, Ying Hu

Journal of Colloid and Interface Science 2011 Volume 356(Issue 2) pp:557-565

Publication Date(Web):15 April 2011

DOI:10.1016/j.jcis.2011.01.067

Two poly(2-(dimethylamino)ethyl methacrylate)-b-poly(acrylic acid) diblock copolymers, PDMAEMA84-b-PAA18 and PDMAEMA50-b-PAA18, were synthesized by the atom transfer radical polymerization (ATRP) and their dual-stimuli responsive behaviors to the changes in temperature and pH in aqueous solutions were investigated by UV–vis spectroscopy, dynamic light scattering (DLS), 1H NMR spectroscopy and surface tension measurement. Different from PDMAEMA84-b-PAA18 solutions where no aggregation is observed between pH 7.0 and 9.5, the PDMAEMA50-b-PAA18 aggregates can exist in this broad pH range due to the hydrophobic interactions among the charge-balanced polyampholyte chains. At high pH, e.g., 11.0, the DMAEMA segments collapse to form the core of micelles due to the hydrophobic property of the de-protonized DMAEMA stabilized with the highly ionized AA segments on the surface of the micelles upon heating. At pH around the IEP, e.g., 9.5, large micelles can be formed in PDMAEMA84-b-PAA18 solution upon heating, just like that at pH 11.0, while PDMAEMA50-b-PAA18 first formed the micelles due to the electrostatic attraction between ionized AA segments and protonated DMAEMA segments, but the aggregation of the micelles was hardly happened upon heating due to the smaller DMAEMA segment. Moreover, LCST can be exactly estimated by surface tension experiment.Graphical abstractThe proposed model for two PDMAEMA-b-PAA aggregation behavior responded to changes in temperature and pH in aqueous solutions.Research highlights► PDMAEMA-b-PAA copolymers have pH and thermo dual-stimuli sensitivities. ► Thermal sensitivity of PDMAEMA-b-PAA is reversible. ► LCST varies with solution concentration, pH and thermal-segment lengths. ► LCST can be exactly estimated by surface tension experiment.

Nanopatterns of ABA triblock copolymer thin films formed on water surface

Co-reporter:Yuan Zhou, Xia Han, Jun Hu, Yongmin Huang, Honglai Liu

Thin Solid Films 2011 Volume 519(Issue 19) pp:6629-6636

Publication Date(Web):29 July 2011

DOI:10.1016/j.tsf.2011.04.238

Nanopatterns of hydrophobic triblock copolymer SEBS thin films formed on a water surface by using drop spreading casting and dilute solution casting methods have been studied. It is found that the surface morphologies of thin films, as well as the spreading behavior of polymer solutions on water, depend strongly on the selectivity of the solvent and the functional group which interacts with the water subphase. The resulting nanopatterns were examined in terms of the relative interaction parameter (Δχ) and the copolymer volume fraction (ϕ) in the solution, based on the physics of solvent annealing and evaporation.

Aggregation behavior of N-carboxyethylchitosan in aqueous solution: effects of pH, polymer concentration, and presence of a gemini surfactant

Co-reporter:Baoliang Peng, Yongliang Hao, Hongmei Kang, Xia Han, Changjun Peng, Honglai Liu

Carbohydrate Research 2010 Volume 345(Issue 1) pp:101-107

Publication Date(Web):11 January 2010

DOI:10.1016/j.carres.2009.10.018

A kind of biocompatible derivative of chitosan, N-carboxyethylchitosan (CECh) with a degree of substitution of 0.21 (DS 0.21) was synthesized by a Michael addition reaction. The aggregation behavior of CECh in aqueous solution under the effects of pH, polymer concentration, as well as a gemini surfactant, was investigated by turbidity, zeta potential, fluorescence spectroscopy, viscosity, and surface tension measurements. In the pH range of 3–11, the macroscopic phase separation of CECh from water occurs near the isoelectric point (IEP) due to the intense electrostatic attraction, and the intermolecular interaction at pH 4 is stronger than that at pH 10 over the whole CECh concentration region. The critical aggregation concentration (CAC) of CECh/12-n-12 (n = 3, 6) in basic media is determined to be between 0.0010 and 0.0015 mmol/L, and the length of the surfactant spacer is found to play an important role in the interaction of 12-n-12 with CECh.

Effects of pore structure of mesoporous silicas on the electrochemical properties of hemoglobin

Co-reporter:Jinxia Li, Zhiying Xiong, Lihui Zhou, Xia Han, Honglai Liu

Microporous and Mesoporous Materials 2010 130(1–3) pp: 333-337

Publication Date(Web):

DOI:10.1016/j.micromeso.2009.11.031

Crystallization behavior of wet brush and dry brush blends of PS-b-PEO-b-PS/h-PEO

Co-reporter:Chunyan Luo;Ying Gao;Honglai Liu;Ying Hu

Journal of Applied Polymer Science 2009 Volume 113( Issue 2) pp:907-915

Publication Date(Web):

DOI:10.1002/app.30004

Abstract

The crystallization behavior of the blending system consists of homopolymer poly(ethylene oxide) (h-PEO) with different molecular weights, and polystyrene-block-poly (ethylene oxide)-block-polystyrene (PS-b-PEO-b-PS) triblock copolymer has been investigated by DSC measurements. The crystallization of PEO block (b-PEO) in block copolymer occurs under much lower temperature than that of the h-PEO in the bulk (ΔT > 65 °C), which is attributed to the homogeneous nucleation crystallization behavior of the b-PEO microdomains. In both the “dry-brush” and the “wet brush” blending systems, the homogeneous nucleation crystallization temperature of PS-b-PEO-b-PS/h-PEO blends increases due to the increase of the domain size. The heterogeneous nucleation crystallization temperatures of h-PEO in the wet brush blending systems are higher than that of the corresponding h-PEO in the bulk. At the same time, the heterogeneous nucleation crystallization temperature of b-PEO10000 decreases from 43°C to 30°C and 40°C in the h-PEO600 and h-PEO2000 blending systems, respectively, because of the stretching of the PEO chains in the wet brush. However, this kind of phenomenon does not happen in the dry brush blending systems. The self-seeding procedure was used to further ascertain the nucleation mechanism in the crystallization process. As a result, the self-seeding domains have been confirmed, and the difference between the dry brush and wet brush systems has been observed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Direct electrochemistry of hemoglobin immobilized on siliceous mesostructured cellular foam

Co-reporter:Jinxia Li, Lihui Zhou, Xia Han, Jun Hu, Honglai Liu, Jian Xu

Sensors and Actuators B: Chemical 2009 Volume 138(Issue 2) pp:545-549

Publication Date(Web):6 May 2009

DOI:10.1016/j.snb.2009.02.035

The direct electrochemistry of hemoglobin (Hb) immobilized on the siliceous mesostructured cellular foam (MCF) modified glassy carbon electrode (GC) was presented. Using a simple physical adsorption method, Hb was immobilized on MCF and the influences of concentration of Hb and the pH value of solution were investigated. UV–vis and FTIR spectra displayed that Hb maintained its natural structure inside the pores of MCF. The electrochemical property of Hb/MCF/GC modified electrode was studied by cyclic voltammetry. A couple of quasi-reversible redox peaks of Hb were observed on the Hb/MCF/GC electrode at about −0.396 V and −0.321 V in PBS (pH 7.0). The results indicated that MCF provided a favorable microenvironment for immobilization of Hb and facilitated the electron transfer between Hb and electrode surface.

In-situ Observation of the Growth of Fibrous and Dendritic Crystals in Quasi-2-dimensional Poly(ethylene oxide) Ultrathin Films

Co-reporter:Yuan ZHOU, Xia HAN, Honglai LIU, Ying HU

Chinese Journal of Chemical Engineering (March 2014) Volume 22(Issue 3) pp:339-345

Publication Date(Web):1 March 2014

DOI:10.1016/S1004-9541(14)60046-X

Crystal growth processes of poly(ethylene ! oxide) were followed from the original nucleation sites by using atomic force microscopy. Two distinct quasi-2-dimensional crystals about 4 nm thick were obtained from as-spun polymer ultrathin films: fibrous crystals, generated by the shearing field via spin-coating, coexist with conventional dendrites. The growth of the two structures is dominated by diffusion limited aggregation, though the growth rate of the fibrous crystals is around one order of magnitude faster than that of the dendrites. The fibrous crystals are more stable than the dendritic ones.

Transferrin gated mesoporous silica nanoparticles for redox-responsive and targeted drug delivery

Co-reporter:Xiaolu Chen, Hui Sun, Jun Hu, Xia Han, Honglai Liu, Ying Hu

Colloids and Surfaces B: Biointerfaces (1 April 2017) Volume 152() pp:

Publication Date(Web):1 April 2017

DOI:10.1016/j.colsurfb.2017.01.010

•Transferrin modified MSNs via disulfide bonds were designed and fabricated.•Transferrin serves as both a gatekeeper and a targeting ligand simultaneously.•The hybrid MSNs showed a redox-responsive drug release behavior.•The hybrid MSNs showed enhanced cellular uptake efficacy and anticancer effect.This work reports on a targeted and controlled drug delivery system based on protein decorated mesoporous silica nanoparticles (MSNs). In this system, transferrin (Tf), a naturally existing protein, is grafted on the surfaces of MSNs via redox-cleavable disulfide bonds, serving as both a capping agent and a targeting ligand simultaneously. The uniform particles with ordered mesoporous structures and the successful construction of the Tf/MSN hybrid nanocarriers can be confirmed through combined techniques. It is found that the model anticancer drug doxorubicin (DOX) can be efficiently encapsulated in the MSNs in the absence of glutathione (GSH), and a burst release of DOX is observed when the system is exposed to GSH, indicating good capping efficiency of Tf and redox-responsive release of DOX. Owing to the biocompatible Tf shell, the hybrid nanocarriers exhibited excellent biocompatibility in a wide concentration range and enhanced intracellular accumulation and targeting capability to tumor cells in vitro. The facile approach and the strategy of integration of multifunctions into one moiety present great potential in site-specific, controlled-release drug delivery system and provide us new ideas in design of MSN-based nanocontainers.Mesoporous silica nanoparticles with transferrin as both capping and targeting agents promise a great potential in site-specific and redox-responsive drug delivery.