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EFFECT OF SURFACE CHARGE OF POLYMERIC MICELLES ON IN VITRO CELLULAR UPTAKE

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Chinese Journal of Polymer Science 2013年第9期31卷 1299-1309页

作者： Dan-hua Zhou Jie Zhang Guan Zhang zhi-hua gan CAS Key Laboratory of Engineering Plastics Institute of Chemistry Chinese Academy of Sciences Novelty Research Station for SCI-TECH Beijing University of Chemical Technology Department of Urology China-Japan Friendship Hospital State Key Laboratory of Organic-inorganic Composites Beijing Laboratory of Biomedical Materials College of Life Science and Technology Beijing University of Chemical Technology

This work focuses on the interaction between polymeric micelles with different charged surfaces and cancer cells in order to study the influence of surface charge on the in vitro cellular uptake efficiency. The amphiphilic diblock copolymers poly（e-caprolaetone）-b-poly（ethylene oxide）（PCL-b-PEO） with different functional groups at the end of hydrophilic block were synthesized. The functional groups endue the micelles with different charges on the surfaces. The cellular uptake of micelles to T-24 cells （human bladder tumor cells）, HepG2 cells （human liver hepatocellular carcinoma cell line） and Hela cells （human epithelial cervical cancer cells） was studied by means of flow cytometer and confbcal laser scanning microscopy. The results indicate that the surface charges showed great influence on zeta potential of micelles at different pH values. The in vitro cellular uptake efficiency of micelles with different charged surfaces demonstrated different cellular uptake patterns to three kinds of cancer cells.

关键词： Polymeric micelles Surface charge pH value Cellular uptake efficiency.

Folic Acid Modified Polymeric Micelles for Intravesical Instilled Chemotherapy

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Chinese Journal of Polymer Science 2018年第4期36卷 479-487页

作者： Dan-hua Zhou Guan Zhang Qing-Song Yu zhi-hua gan National University of Singapore Environmental Research Institute(NERI) National University of SingaporeSingapore 117576Singapore Beijing Advanced Innovation Center for Soft Matter Science and Engineering State Key Laboratory of Organic-inorganic Composite MaterialsCollege of Life Science and TechnologyBeijing University of Chemical TechnologyBeijing 100029China Department of Urology China-Japan Friendship HospitalBeijing 100029China

In this study, a targeting micellar drug delivery system was developed for intravesical instilled chemotherapy of bladder cancer. The amphiphilic diblock copolymer poly（？-caprolactone）-block-poly（ethylene glycol）（PCL-b-PEO） with functional amino group（NH2） at the end of PEO block was synthesized. Then the copolymer was conjugated with folic acid（FA） and fluorescein isothiocyannate（FITC） via the PEO-NH2 terminus, and then assembled into micelles with the target moiety and fluorescence labeling. In addition, drug loaded micelles were also fabricated with anticancer drug doxorubicin（DOX） encapsulated in the hydrophobic core. The micelles were characterized in terms of size, drug loaded efficiency and critical micellization concentration（CMC） by means of DLS, UV and fluorescence spectra. In vitro cellular uptake and cytotoxicity studies showed that FA modified PCL-b-PEO-FA micelles have a greater targeting efficiency to human bladder cancer cell（T-24 cell） compared to PCL-b-PEO-NH2 micelles due to the conjugation of FA on the surface, while no targeting effect to normal tissue originated human embryonic kidney 293（HEK-293） cells was observed, enabling the micelles a promising drug carrier for intravesical instilled chemotherapy of bladder cancer.

关键词： Targeted drug delivery Superficial bladder cancer Intravesical instilled chemotherapy Folic acid Micelles

Influence of compression-expansion effect on oscillating-flow heat transfer in a finned heat exchanger

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第6期14卷 427-434页

作者： Ke TANG Juan YU Tao JIN zhi-hua gan Institute of Refrigeration and Cryogenics Zhejiang University

Compression and expansion of a working gas due to the pressure oscillation of an oscillating flow can lead to a temperature variation of the working gas, which will affect the heat transfer in the oscillating flow. This study focuses on the impact of the compression-expansion effect, indicated by the pressure ratio, on the heat transfer in a finned heat exchanger under practical operating conditions of the ambient-temperature heat exchangers in Stirling-type pulse tube refrigerators. The experimental results summarized as the Nusselt number are presented for analysis. An increase in the pressure ratio can result in a marked rise in the Nusselt number, which indicates that the compression-expansion effect should be considered in characterizing the heat transfer of the oscillating flow, especially in the cases with a higher Valensi number and a lower maximum Reynolds number.

关键词： Heat transfer Heat exchanger Oscillating flow Pressure ratio Pulse robe refrigerator

Preparation of Porous Polylactide Microspheres and Their Application in Tissue Engineering

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Chinese Journal of Polymer Science 2018年第6期36卷 712-719页

作者： Xu-Dong Shi Pei-Jian Sun zhi-hua gan Key Laboratory of Polymer Ecomaterials Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China The GAS Key Laboratory of Engineering Plastics Institute of ChemistryChinese Academy of Sciences(CAS)Beijing 100190China State Key Laboratory of Organic-inorganic Composites College of Life Science and TechnologyBeijing University of Chemical TechnologyBeijing 100029China

In this study, porous polylactide（PLA） microspheres with different structures were prepared through the multiple emulsion solvent evaporation method. By changing organic solvents（ethyl acetate and chloroform） and adding effervescent salt NH4 HCO3 in the inner water phase, microspheres with porous capsular, matrix, microcapsular and multivesicular structures were prepared. The protein encapsulation and release, and the cell growth behavior of porous microspheres were further explored. Under the same inner water phase, microspheres prepared with chloroform had higher protein encapsulation efficiency and less protein release rate as compared with those prepared with ethyl acetate. Cell experiments showed that the relatively rough surface of microspheres prepared with chloroform was more favorable for the cell growth in comparison with the smooth surface of microspheres prepared with ethyl acetate. This study shows a simple and effective method to control the protein release and cell growth behaviors of polymer microspheres by tuning their porous structure.

关键词： Polylactide Porous microspheres Drug release Cell Tissue engineering

Computational fluid dynamic simulation of an inter-phasing pulse tube cooler

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第1期9卷 93-98页

作者： Xiao-bin ZHANG zhi-hua gan Li-min QIU hua-xiang LIU Institute of Refrigeration and Cryogenics Zhejiang University Hangzhou 310027 China College of Science Guangdong Ocean University Zhanjiang 524088 China

An inter-phasing pulse tube cooler (IPPTC) consists of two pulse tube units, which are connected to each other at hot ends of the pulse tubes through a needle valve. This paper presents the computational fluid dynamic (CFD) results of an IPPTC using a 2D axis-symmetrical model. General results such as the phase difference between pressure and velocity at cold end and hot end, the temperature profiles along the wall, the available lowest temperature as well as its oscillations and the coefficient of performance (COP) for IPPTC are presented. The formation of DC flow and its effects on the performance of the cooler are investigated and analyzed in detail. Turbulence, which is partially responsible for the poor overall performance of a single orifice pulse tube cooler (OPTC), is found to be much reduced in IPPTC and its performance is improved significantly compared with the single OPTC.

关键词： Inner-phasing Pulse tube cooler (PTC) Computational fluid dynamic (CFD)

Paclitaxel Prodrug Nanomedicine for Potential CT-imaging Guided Breast Cancer Therapy

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Chinese Journal of Polymer Science 2023年第11期41卷 1747-1759,I0008页

作者： Jia-Wei Chen Yi Shen Qing-Song Yu zhi-hua gan State Key Laboratory of Organic-Inorganic Composite Materials Beijing Laboratory of Biomedical MaterialsBeijing Advanced Innovation Center for Soft Matter Science and EngineeringCollege of Life Science and TechnologyBeijing University of Chemical TechnologyBeijing 100029China

Nanotheranostics,which combine the therapeutic and diagnostic functions in one integrated system,have received extensive attentions in cancer treatments because they enable non-invasive diagnosis,tumor-targeted drug delivery,and real-time monitoring of therapeutic ***,due to the high systemic toxicity of commonly used chemotherapeutics,current treatment still has ***,to simultaneously achieve safe cancer therapy and therapeutic response monitoring,an iodinated prodrug strategy was proposed.2,3,5-Triiodobenzoic acid(TIBA)was used to modify both paclitaxel(PTX)and the polymeric vehicle,so that the encapsulation efficiency of PTX could be increased and the systemic toxicity could be ***-prepared prodrug nanoparticles could accumulate passively in the tumor site and promptly release loaded drugs in response to the overexpressed GSH in cancer cells,which then caused efficient cell cycle arrest and apoptosis like that of the parent *** this rational design,safe and efficient antitumor therapy and real-time computer tomography(CT)imaging could be simultaneously realized,facilitating potential CT imaging-guided therapy of metastatic breast cancer.

关键词： CT imaging Paclitaxel Prodrug GSH responsiveness Polymeric nanoparticles

Liquid film dryout model for predicting critical heat flux in annular two-phase flow

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第3期10卷 398-417页

作者： Bo JIAO Li-min QIU Jun-liang LU zhi-hua gan Institute of Refrigeration and Cryogenic Engineering Zhejiang University Hangzhou 310027 China

Gas-liquid two-phase flow and heat transfer can be encountered in numerous fields, such as chemical engineering, refrigeration, nuclear power reactor, metallurgical industry, spaceflight. Its critical heat flux (CHF) is one of the most important factors for the system security of engineering applications. Since annular flow is the most common flow pattern in gas-liquid two-phase flow, predicting CHF of annular two-phase flow is more significant. Many studies have shown that the liquid film dryout model is successful for that prediction, and determining the following parameters will exert predominant effects on the accuracy of this model: onset of annular flow, inception criterion for droplets entrainment, entrainment fraction, droplets deposition and entrainment rates. The main theoretical results achieved on the above five parameters are reviewed; also, limitations in the existing studies and problems for further research are discussed.

关键词： Annular two-phase flow Critical heat flux (CHF) Liquid film dryout Deposition rate Entrainment rate

Synergistic Effect of Multi-Arm Architecture and Molecular Weight on Crystallization and Degradation Behavior of Star-Shaped Poly(Lactic Acid)

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Chinese Journal of Polymer Science 2024年第12期42卷 1948-1956,I0009页

作者： Nan Tian Yi-Qing Li Hong-Yi gan Zhen-Bo Ning Ni Jiang zhi-hua gan State Key Laboratory of Organic-inorganic Composites Beijing Laboratory of BiomaterialsCollege of Life Science and TechnologyBeijing University of Chemical TechnologyBeijing100029China Institute of Material Sinopec Beijing Research Institute of Chemical IndustryBeijing100013China

Star-shaped poly(lactic acid)s(PLAs)with two to five arms were synthesized by ring opening polymerization using tin(II)2-ethylhexanoate as catalyst and polyols as *** effects of molecular weight together with multi-arm architecture on crystallization behavior,spherulite morphology and alkaline degradation behavior of star-shaped PLAs have been *** results indicate that the multi-arm architecture interfered with spherulite growth,but promoted nucleation and alkaline degradation of star-shaped ***,with the increase of molecular weight(M_(n)),the crystallization rate first increased and then decreased,while the alkaline degradation rate was the *** characteristic crystallization and alkaline degradation behavior of star-shaped PLAs were discussed based on the competition between segmental mobility and central core confinement.

关键词： Star-shaped poly(lactic acid) Crystallization Spherulite morphology Alkaline degradation

Biodegradable Microspheres with Poly(N-isopropylacrylamide) Enriched Surface: Thermo-responsibility, Biodegradation and Drug Release

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Chinese Journal of Polymer Science 2015年第11期33卷 1598-1605页

作者： Yin Yuan 孙培健 Xu-dong Shi zhi-hua gan 王佛松 CAS Key Laboratory of Engineering Plastics Institute of Chemistry Chinese Academy of Sciences the Key Laboratory of Tobacco Chemistry Zhengzhou Tobacco Research Institute China National Tobacco Corporation State Key Laboratory of Organic-inorganic Composites Beijing Laboratory of Biomedical MaterialsCollege of Life Sciences and Technology

Microspheres with thermo-responsible surface were fabricated by PCL-b-PEO-b-PNIPAM triblock copolymers. Thermo-responsible morphological changes of PCL-b-PEO-b-PNIPAM microspheres immersed in aqueous solution at temperatures above the LCST（e.g. 37 ℃） were observed from porous surface structure to compact surface layer. Enzymatic degradation and in vitro drug release results showed that the thermo-responsible surface layer greatly influenced the degradation of microspheres as well as the drug release behavior from microspheres. With the copolymerization of PNIPAM block into PCL-b-PEO copolymers, the drug release could be well regulated by changing temperatures and microspheres composition, which revealed the great potentials of microspheres with thermo-responsible surface for controlled drug release.

关键词： Microspheres Poly(N-isopropylacrylamide) Thermo-sensitive Biodegradation