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Progress in fabricating arrays of soft spherical vessels on mesoscale with spatial control

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Chinese Science Bulletin 2008年第22期53卷 3477-3490页

作者： YANG Jie gao changyou Key Laboratory of Macromolecular Synthesis and Functionalization Ministry of Education Department of Polymer Science and Engineering Zhejiang University Hangzhou 310027 China

Microarrays of spherical vessel-like colloids such as liposomes, polymerized vesicles and polyelec-trolyte capsules may find diverse applications in bioanalysis, biosensing, and combinatorial chemistry, for their capabilities in encapsulating chemical species such as drugs, biomolecules, probes, polymers and nanoparticles. This review reports the advances on methods for fabricating microarrays of the various hollow colloids. Related strategies are described in detail, including patterning techniques, surface modification methods, and tethering approaches such as oligonucleotide hybridization, receptor-ligand binding, covalent coupling and electrostatic interaction. The preliminary developments of functionalities of these arrays serving as sensor chips, microcarriers and microreactors are summarized as well.

关键词：泡状体脂质体微胶囊空间控制

Biological identity of nanomaterials:Opportunities and challenges

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Science China Chemistry 2013年第11期56卷 1533-1541页

作者： DENG Jun YU DaHai gao changyou MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang University

The emergence of nanoparticles(NPs)has attracted tremendous interest of the scientific community for decades due to their unique properties and potential applications in diverse areas,including drug delivery and *** novel NPs have been synthesized and used to reduce drug toxicity,improve bio-availability,prolong circulation time,control drug release,and actively target to desired cells or ***,clinical translation of NPs with the goal of treating particularly challenging diseases,such as cancer,will require a thorough understanding of how the NP properties influence their fate in biological systems,especially in *** efforts have been paid to studying the interactions and mechanisms of NPs and *** deliberately designed,the NPs in contact with biological fluids are rapidly covered by a selected group of biomolecules especially proteins to form a corona that interacts with biological *** this view,the recent development of NPs in drug delivery and the interactions of NPs with cells and proteins are *** understanding the protein-NP interactions,some guidelines for safety design of NPs,challenges and future perspectives are discussed.

关键词： nanoparticles carriers cellular uptake protein corona

Surface-grafted block copolymer brushes with continuous composition gradients of poly(poly(ethylene glycol)-monomethacrylate) and poly(N-isopropylacrylamide)

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Science China Chemistry 2011年第2期54卷 334-342页

作者： LI LinHui WU JinDan gao changyou MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027China

Surface-grafted block copolymer brushes with continuous composition gradients containing poly(poly(ethylene glycol) monomethacrylate) (P(PEGMA)) and poly(N-isopropylacrylamide) (PNIPAAm) chains were fabricated by integration of the surface-initiated atom transfer radical polymerization (SI-ATRP) and continuous injection method. Three types of copolymer gradients were prepared: (1) a uniform P(PEGMA) layer was block copolymerized with a gradient PNIPAAm layer (PP1); (2) a gradient P(PEGMA) layer was block copolymerized with a uniform PNIPAAm layer (PP2); and (3) a gradient P(PEGMA) layer was inversely block copolymerized with a gradient PNIPAAm layer (PP3). The as-prepared gradients were characterized by ellipsometry, water contact angle and atomic force microscopy (AFM) to determine their alterations in thickness, surface wettability and morphology, confirming the gradient structures. In vitro culture of HepG2 cells was implemented on the gradient surfaces, revealing that the cells could adhere at 37 ℃ and be detached at 20 ℃. Introduction of the PEG chains as an underlying layer on the PNIPAAm grafting surfaces resulted in faster cell detachment compared with the PNIPAAm grafting surface.

关键词： gradients ATRP PNIPAAm cell attachment thermo-responsive

Induced migration of endothelial cells into 3D scaffolds by chemoattractants secreted by pro-inflammatory macrophages in situ

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Regenerative Biomaterials 2017年第3期4卷 139-148页

作者： Xuguang Li Yuankun Dai Tao Shen changyou gao MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027China

Cell migration in scaffolds plays a crucial role in tissue regeneration,which can better mimic cell behaviors in *** this study,a novel model has been proposed on controlling 3D cell migration in porous collagen-chitosan scaffolds with various pore structures under the stimulation of inflammatory cells to mimic the angiogenesis *** cells(ECs)cultured atop the scaffolds in the Transwell molds which were placed into a well of a 24-well culture plate were promoted to migrate into the scaffolds by chemoattractants such as vascular endothelial growth factor(VEGF)and tumor necrosis factor-alpha(TNF-α)secreted by the pro-inflammatory macrophages incubated in the well culture *** phenotype of macrophages was mediated by 50 ng/ml interferongamma(IFN-c)and different concentrations of lipopolysaccharide(LPS,150–300 ng/ml).The cell migration depth had a positive correlation with LPS concentration,and thereby the TNF-a *** ECs migrated easier to a deeper zone of the scaffolds prepared at10C(187 lm in pore diameter)than that at20C(108 lm in pore diameter)as *** method provides a useful strategy to study the 3D cell migration,and is helpful to reveal the vascularization process during wound healing in the long run.

关键词： cell migration chemoattractants endothelial cells macrophages scaffolds

Migration of endothelial cells into photo-responsive hydrogels with tunable modulus under the presence of pro-inflammatory macrophages

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Regenerative Biomaterials 2019年第5期6卷 259-267页

作者： Wangbei Cao Xuguang Li Xingang Zuo changyou gao MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027China

Cell migration in three-dimensional environment is extremely important for tissue regeneration and other biological *** this work,a model system was developed to study how endothelial cells(ECs)migrate into photo-responsive hydrogels under the presence of pro-inflammatory *** hydrogel was synthesized from hyaluronic acid grafted with coumarin and methacrylate moieties by both carbon–carbon covalent linking and coumarin dimerization under UV irradiation at 365 *** structure of the hydrogel was conveniently modulated by UV irradiation at 254nm to decompose the coumarin dimers,leading to the significant decrease of modulus and increase of swelling ratio and mesh *** the presence of M1 macrophages,ECs were induced to migrate into the hydrogels with a different degree.A significant larger net displacement of ECs was found in the softer hydrogel obtained by irradiation with UV at 254nm than in the stiffer original one at day 7.

关键词： 3D cell migration immune-response hydrogel photo-responsive hyaluronic acid

In-depth study on aminolysis of poly(ε-caprolactone): Back to the fundamentals

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Science China Chemistry 2012年第11期55卷 2419-2427页

作者： ZHU Yang MAO ZhengWei SHI HuaYu gao changyou MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027China

The aminolysis can effectively introduce primary amine （- quent surface fiiofunctionalization reactions. However, less NH2） groups onto polyester materials, enabling a variety of subse- attention has been paid to the basic knowledge of aminolysis reac- tion in terms of reaction kinetics and its influences on materials properties. In this study, taking the widely used poly（e-caprolactone）（PCL） as a typical example, the influences of diamines and solvent property on the surface -NH2 density are firstly assessed by using X-ray photoelectron spectroscopy （XPS） and colorimetric analysis. Results show that smaller dia- mine molecules and nonpolar alcohols could accelerate the reaction. The reaction kinetics with 1,6-hexanediamine is further investigated as a function of temperature, reaction time, and diamine concentration. During the initial stage, the reaction shows a 1^st order kinetics with the diamine concentration and has an activation energy of 54.5 kJ/mol. Ionization state of the -NH2 groups on the PCL surface is determined, revealing that the pKa of -NH3^＋（〈5） is much lower than that of the corresponding diamine molecules in solution. After aminolysis, surface hydrophilicity of PCL membrane is significantly enhanced, while surface elastic modulus and average molecular weight are decreased to some extent, and others such as weight, surface mor- phology and bulk mechanical strength are not apparently changed. The introduced -NH2 groups are found to be largely lost at 37 ℃, but can be mostly maintained at low temperature.

关键词： poly(ε-caprolactone) aminolysis surface modification biomaterials

Covalently immobilized gelatin gradients within three-dimensional porous scaffolds

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Chinese Science Bulletin 2009年第18期54卷 3174-3180页

作者： WU JinDan TAN HuaPing LI LinHui gao changyou Key Laboratory of Macromolecular Synthesis and Functionalization Ministry of Education and Department of Science and Engineering Zhejiang University Hangzhou 310027 China

A stable gelatin gradient providing continuous increment of signaling for cell adhesion and proliferation was fabricated within 3D poly(L-lactic acid) (PLLA) scaffolds. The porous PLLA scaffold fabricated by NaCl particle leaching was vertically fixed on a glass vial. 1,6-Hexanediamine/propanol solution was continuously injected into the vial by a micropump to aminolyze the PLLA scaffold. As a result of reaction time difference, the introduced -NH2 groups increased continuously along with the longitude of the PLLA scaffold in the z-direction. After covalent immobilization of gelatin by glutaraldehyde coupling, the gelatin gradient scaffold was thus obtained. In vitro chondrocyte culture showed that the cells had higher viability and more extending morphology in the gelatin gradient scaffold than that in the uniform gelatin control.

关键词：多孔支架共价固定明胶梯度三维细胞粘附聚乳酸金属制品

Solvent-assisted polymer micro-molding

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Chinese Science Bulletin 2009年第13期54卷 2193-2204页

作者： HAN LuLu ZHOU Jing GONG Xiao gao changyou Department of Polymer Science and Engineering Zhejiang University Hangzhou 310027 China

The micro-molding technology has played an important role in fabrication of polymer micro-patterns and development of functional *** such a process,suitable solvent can swell or dissolve the polymer films to decrease their glass transition temperature(Tg) and viscosity and thereby improve flowing ***,it is easy to obtain the 2D and 3D patterns with high fidelity by the solvent-assisted *** with the high temperature molding,this technology overcomes some shortcomings such as shrinking after cooling,degradation at high temperature,difficulty in processing some functional materials having high Tg,*** can be applied to making patterns not only on polymer monolayers but also on polyelectrolyte ***,the compression-induced patterns on the multilayers are chemically homogenous but physically *** this review,the controlling factors on the pattern quality are also discussed,including materials of the mold,solvent,pressure,temperature and pattern density.

关键词：聚合物膜微成型溶剂玻璃化转变温度聚电解质多层膜成型技术功能材料功能器件

Gold nanoparticles with surface-anchored chiral poly（acryloyI-L（D）-valine） induce differential response on mesenchymal stem cell osteogenesis

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Nano Research 2016年第12期9卷 3683-3694页

作者： Jun Deng Honghao Zheng Xiaowen Zheng Mengyun Yao Zheng Li changyou gao MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and Engineering ZhejiangUniversity Hangzhou 310027 China

Chirality is one of the most distinctive biochemical signatures of life, and plays crucial roles in maintaining normal functions of living cells or organisms. Pioneering work from another group has demonstrated the dependency of cell differentiation on the chirality of nano-coated substrates, but the effect of the chiral surface of nanoparticles on stem cell fates has not been investigated. In this study, the influence of molecular chiral poly（acryloyl-L（D）-valine）（L（D）- PAV）-anchored gold nanoparticles （L（D）-PAV-AuNPs） on the differentiation of mesenchymal stem cells （MSCs） was investigated. Though osteogenic differentiation of MSCs was not affected by D-PAV-AuNPs, it was significantly promoted by L-PAV-AuNPs in terms of calcium deposition, alkaline phosphatase （ALP） activity, and expression of collagen type I and osteocalcin （OCN） at both mRNA and protein levels. L-PAV-AuNPs could activate the P38 mitogen-activated protein kinase （MAPK） pathway, and may exert mechanical stress on MSCs because of high amounts of internalization. These results provide new insights on surface chirality at the nanoscale as a direct regulator to guide the differentiation of MSCs, and the use of these nanomaterials for strategic regenerative medicine.

关键词： chiralpoly(acryloyl-L(D)-valine) gold nanoparticles mesenchymal stem cells osteogenic differentiation