@article{WangNaolouMaetal.2017, author = {Wang, Weiwei and Naolou, Toufik and Ma, Nan and Deng, Zijun and Xu, Xun and Mansfeld, Ulrich and Wischke, Christian and Gossen, Manfred and Neffe, Axel T. and Lendlein, Andreas}, title = {Polydepsipeptide Block-Stabilized Polyplexes for Efficient Transfection of Primary Human Cells}, series = {Biomacromolecules : an interdisciplinary journal focused at the interface of polymer science and the biological sciences}, volume = {18}, journal = {Biomacromolecules : an interdisciplinary journal focused at the interface of polymer science and the biological sciences}, publisher = {American Chemical Society}, address = {Washington}, issn = {1525-7797}, doi = {10.1021/acs.biomac.7b01034}, pages = {3819 -- 3833}, year = {2017}, abstract = {The rational design of a polyplex gene carrier aims to balance maximal effectiveness of nucleic acid transfection into cells with minimal adverse effects. Depsipeptide blocks with an M (n) similar to 5 kDa exhibiting strong physical interactions were conjugated with PEI moieties (2.5 or 10 kDa) to di- and triblock copolymers. Upon nanoparticle formation and complexation with DNA, the resulting polyplexes (sizes typically 60-150 nm) showed remarkable stability compared to PEI-only or lipoplex and facilitated efficient gene delivery. Intracellular trafficking was visualized by observing fluorescence-labeled pDNA and highlighted the effective cytoplasmic uptake of polyplexes and release of DNA to the perinuclear space. Specifically, a triblock copolymer with a middle depsipeptide block and two 10 kDa PEI swallowtail structures mediated the highest levels of transgenic VEGF secretion in mesenchymal stem cells with low cytotoxicity. These nanocarriers form the basis for a delivery platform technology, especially for gene transfer to primary human cells.}, language = {en} } @article{WangRazzaqRudolphetal.2018, author = {Wang, Li and Razzaq, Muhammad Yasar and Rudolph, Tobias and Heuchel, Matthias and N{\"o}chel, Ulrich and Mansfeld, Ulrich and Jiang, Yi and Gould, Oliver E. C. and Behl, Marc and Kratz, Karl and Lendlein, Andreas}, title = {Reprogrammable, magnetically controlled polymeric nanocomposite actuators}, series = {Material horizons}, volume = {5}, journal = {Material horizons}, number = {5}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {2051-6347}, doi = {10.1039/c8mh00266e}, pages = {861 -- 867}, year = {2018}, abstract = {Soft robots and devices with the advanced capability to perform adaptive motions similar to that of human beings often have stimuli-sensitive polymeric materials as the key actuating component. The external signals triggering the smart polymers' actuations can be transmitted either via a direct physical connection between actuator and controlling unit (tethered) or remotely without a connecting wire. However, the vast majority of such polymeric actuator materials are limited to one specific type of motion as their geometrical information is chemically fixed. Here, we present magnetically driven nanocomposite actuators, which can be reversibly reprogrammed to different actuation geometries by a solely physical procedure. Our approach is based on nanocomposite materials comprising spatially segregated crystallizable actuation and geometry determining units. Upon exposure to a specific magnetic field strength the actuators' geometric memory is erased by the melting of the geometry determining units allowing the implementation of a new actuator shape. The actuation performance of the nanocomposites can be tuned and the technical significance was demonstrated in a multi-cyclic experiment with several hundreds of repetitive free-standing shape shifts without losing performance.}, language = {en} } @article{JiangMansfeldKratzetal.2019, author = {Jiang, Yi and Mansfeld, Ulrich and Kratz, Karl and Lendlein, Andreas}, title = {Programmable microscale stiffness pattern of flat polymeric substrates by temperature-memo technology}, series = {MRS Communications}, volume = {9}, journal = {MRS Communications}, number = {1}, publisher = {Cambridge Univ. Press}, address = {New York}, issn = {2159-6859}, doi = {10.1557/mrc.2019.24}, pages = {181 -- 188}, year = {2019}, abstract = {Temperature-memory technology was utilized to generate flat substrates with a programmable stiffness pattern from cross-linked poly(ethylene-co-vinyl acetate) substrates with cylindrical microstructures. Programmed substrates were obtained by vertical compression at temperatures in the range from 60 to 100 degrees C and subsequent cooling, whereby a flat substrate was achieved by compression at 72 degrees C, as documented by scanning electron microscopy and atomic force microscopy (AFM). AFM nanoindentation experiments revealed that all programmed substrates exhibited the targeted stiffness pattern. The presented technology for generating polymeric substrates with programmable stiffness pattern should be attractive for applications such as touchpads. optical storage, or cell instructive substrates.}, language = {en} } @article{JiangMansfeldFangetal.2018, author = {Jiang, Yi and Mansfeld, Ulrich and Fang, Liang and Kratz, Karl and Lendlein, Andreas}, title = {Temperature-induced evolution of microstructures on poly[ethylene-co-(vinyl acetate)] substrates switches their underwater wettability}, series = {Materials \& design}, volume = {163}, journal = {Materials \& design}, publisher = {Elsevier}, address = {Oxford}, issn = {0264-1275}, doi = {10.1016/j.matdes.2018.12.002}, pages = {10}, year = {2018}, abstract = {Material surfaces with tailored aerophobicity are crucial for applications where gas bubble wettability has to be controlled, e.g., gas storage and transport, electrodes, bioreactors or medical devices. Here, we present switchable underwater aerophobicity of hydrophobic polymeric substrates, which respond to heat with multilevel micro-and nanotopographical changes. The cross-linked poly[ethylene-co-(vinyl acetate)] substrates possess arrays of microcylinders with a nanorough top surface. It is hypothesized that the specific micro-/nanotopography of the surface allows trapping of a water film at the micro interspace and in this way generates the aerophobic behavior. The structured substrates were programmed to a temporarily stable, nanoscale flat substrate showing aerophilic behavior. Upon heating, the topographical changes caused a switch in contact angle from aerophilic to aerophobic for approaching air bubbles. In this way, the initial adhesion of air bubbles to the programmed flat substrate could be turned into repellence for the recovered substrate surface. The temperature at which the repellence of air bubbles starts can be adjusted from 58 +/- 3 degrees C to 73 +/- 3 degrees C by varying the deformation temperature applied during the temperature-memory programming procedure. The presented actively switching polymeric substrates are attractive candidates for applications, where an on-demand gas bubble repellence is advantageous. (c) 2018 Helmholtz-Zentrum Geesthacht, Zentrum fur Material- und Kustenforschung. Published by Elsevier Ltd.}, language = {en} } @article{BehlBalkMansfeldetal.2021, author = {Behl, Marc and Balk, Maria and Mansfeld, Ulrich and Lendlein, Andreas}, title = {Phase morphology of multiblock copolymers differing in sequence of blocks}, series = {Macromolecular materials and engineering}, volume = {306}, journal = {Macromolecular materials and engineering}, number = {3}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1439-2054}, doi = {10.1002/mame.202000672}, pages = {9}, year = {2021}, abstract = {The chemical nature, the number length of integrated building blocks, as well as their sequence structure impact the phase morphology of multiblock copolymers (MBC) consisting of two non-miscible block types. It is hypothesized that a strictly alternating sequence should impact phase segregation. A library of well-defined MBC obtained by coupling oligo(epsilon-caprolactone) (OCL) of different molecular weights (2, 4, and 8 kDa) with oligotetrahydrofuran (OTHF, 2.9 kDa) via Steglich esterification results in strictly alternating (MBCalt) or random (MBCran) MBC. The three different series has a weight average molecular weight (M-w) of 65 000, 165 000, and 168 000 g mol(-1) for MBCalt and 80 500, 100 000, and 147 600 g mol(-1) for MBCran. When the chain length of OCL building blocks is increased, the tendency for phase segregation is facilitated, which is attributed to the decrease in chain mobility within the MBC. Furthermore, it is found that the phase segregation disturbs the crystallization by causing heterogeneities in the semi-crystalline alignment, which is attributed to an increase of the disorder of the OCL semi-crystalline alignment.}, language = {en} }