TY  - JOUR
A1  - Zou, Jie
A1  - Wang, Weiwei
A1  - Neffe, Axel T.
A1  - Xu, Xun
A1  - Li, Zhengdong
A1  - Deng, Zijun
A1  - Sun, Xianlei
A1  - Ma, Nan
A1  - Lendlein, Andreas
T1  - Adipogenic differentiation of human adipose derived mesenchymal stem cells in 3D architectured gelatin based hydrogels (ArcGel)
JF  - Clinical hemorheology and microcirculation : blood flow and vessels
N2  - Polymeric matrices mimicking multiple functions of the ECM are expected to enable a material induced regeneration of tissues. Here, we investigated the adipogenic differentiation of human adipose derived mesenchymal stem cells (hADSCs) in a 3D architectured gelatin based hydrogel (ArcGel) prepared from gelatin and L-lysine diisocyanate ethyl ester (LDI) in an one-step process, in which the formation of an open porous morphology and the chemical network formation were integrated. The ArcGel was designed to support adipose tissue regeneration with its 3D porous structure, high cell biocompatibility, and mechanical properties compatible with human subcutaneous adipose tissue. The ArcGel could support initial cell adhesion and survival of hADSCs. Under static culture condition, the cells could migrate into the inner part of the scaffold with a depth of 840 +/- 120 mu m after 4 days, and distributed in the whole scaffold (2mm in thickness) within 14 days. The cells proliferated in the scaffold and the fold increase of cell number after 7 days of culture was 2.55 +/- 0.08. The apoptotic rate of hADSCs in the scaffold was similar to that of cells maintained on tissue culture plates. When cultured in adipogenic induction medium, the hADSCs in the scaffold differentiated into adipocytes with a high efficiency (93 +/- 1%). Conclusively, this gelatin based 3D scaffold presented high cell compatibility for hADSC cultivation and differentiation, which could serve as a potential implant material in clinical applications for adipose tissue reparation and regeneration.
KW  - Mesenchymal stem cells
KW  - gelatin based scaffold
KW  - adipose tissue regeneration
KW  - adipogenic differentiation
Y1  - 2017
U6  - https://doi.org/10.3233/CH-179210
SN  - 1386-0291
SN  - 1875-8622
VL  - 67
IS  - 3-4
SP  - 297
EP  - 307
PB  - IOS Press
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Zhou, Shuo
A1  - Xu, Xun
A1  - Ma, Nan
A1  - Jung, Friedrich
A1  - Lendlein, Andreas
T1  - Influence of sterilization conditions on sulfate-functionalized polyGGE
JF  - Clinical hemorheology and microcirculation : blood flow and vessels
N2  - Sulfated biomolecules are known to influence numerous biological processes in all living organisms. Particularly, they contribute to prevent and inhibit the hypercoagulation condition. The failure of polymeric implants and blood contacting devices is often related to hypercoagulation and microbial contamination. Here, bioactive sulfated biomacromolecules are mimicked by sulfation of poly(glycerol glycidyl ether) (polyGGE) films. Autoclaving, gamma-ray irradiation and ethylene oxide (EtO) gas sterilization techniques were applied to functionalized materials. The sulfate group density and hydrophilicity of sulfated polymers were decreased while chain mobility and thermal degradation were enhanced post autoclaving when compared to those after EtO sterilization. These results suggest that a quality control after sterilization is mandatory to ensure the amount and functionality of functionalized groups are retained.
KW  - Sulfated polymer
KW  - sulfation
KW  - sterilization
KW  - ethylene oxide
Y1  - 2021
U6  - https://doi.org/10.3233/CH-211241
SN  - 1386-0291
SN  - 1875-8622
VL  - 79
IS  - 4
SP  - 597
EP  - 608
PB  - IOS Press
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Zhang, Shanshan
A1  - Liu, Yue
A1  - Machatschek, Rainhard Gabriel
A1  - Lendlein, Andreas
T1  - Ultrathin collagen type I films formed at the air-water interface
JF  - MRS advances : a journal of the Materials Research Society (MRS)
N2  - Collagen-based biomaterials with oriented fibrils have shown great application potential in medicine. However, it is still challenging to control the type I collagen fibrillogenesis in ultrathin films. Here, we report an approach to produce cohesive and well-organized type I collagen ultrathin films of about 10 nm thickness using the Langmuir-Blodgett technique. Ellipsometry, rheology, and Brewster angle microscopy are applied to investigate in situ how the molecules behave at the air-water interface, both at room temperature and 37 degrees C. The interfacial storage modulus observed at room temperature vanishes upon heating, indicating the existence and disappearance of the network structure in the protein nanosheet. The films were spanning over holes as large as 1 mm diameter when transferred at room temperature, proving the strong cohesive interactions. A highly aligned and fibrillar structure was observed by atomic force microscopy (AFM) and optical microscopy.
Y1  - 2022
U6  - https://doi.org/10.1557/s43580-021-00160-8
SN  - 2059-8521
VL  - 7
IS  - 4
SP  - 56
EP  - 62
PB  - Springer Nature Switzerland AG
CY  - Cham
ER  - 
TY  - JOUR
A1  - Zhang, Quanchao
A1  - Sauter, Tilman
A1  - Fang, Liang
A1  - Kratz, Karl
A1  - Lendlein, Andreas
T1  - Shape-Memory Capability of Copolyetheresterurethane Microparticles Prepared via Electrospraying
JF  - Macromolecular materials and engineering
N2  - Multifunctional thermo-responsive and degradable microparticles exhibiting a shapememory effect (SME) have attracted widespread interest in biomedicine as switchable delivery vehicles or microactuators. In this work almost spherical solid microparticles with an average diameter of 3.9 +/- 0.9 mm are prepared via electrospraying of a copolyetheresterurethane named PDC, which is composed of crystallizable oligo(p-dioxanone) (OPDO) hard and oligo(e-caprolactone) (OCL) switching segments. The PDC microparticles are programmed via compression at different pressures and their shapememory capability is explored by off-line and online heating experiments. When a low programming pressure of 0.2 MPa is applied a pronounced thermally-induced shape-memory effect is achieved with a shape recovery ratio about 80%, while a high programming pressure of 100 MPa resulted in a weak shape-memory performance. Finally, it is demonstrated that an array of PDC microparticles deposited on a polypropylene (PP) substrate can be successfully programmed into a smart temporary film, which disintegrates upon heating to 60 degrees C.
KW  - biomaterials
KW  - microparticles
KW  - processing
KW  - stimuli-sensitive polymers
KW  - shape-memory effect
Y1  - 2015
U6  - https://doi.org/10.1002/mame.201400267
SN  - 1438-7492
SN  - 1439-2054
VL  - 300
IS  - 5
SP  - 522
EP  - 530
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Zhang, Quanchao
A1  - Rudolph, Tobias
A1  - Benitez, Alejandro J.
A1  - Gould, Oliver E. C.
A1  - Behl, Marc
A1  - Kratz, Karl
A1  - Lendlein, Andreas
T1  - Temperature-controlled reversible pore size change of electrospun fibrous shape-memory polymer actuator based meshes
JF  - Smart materials and structures
N2  - Fibrous membranes capable of dynamically responding to external stimuli are highly desirable in textiles and biomedical materials, where adaptive behavior is required to accommodate complex environmental changes. For example, the creation of fabrics with temperature-dependent moisture permeability or self-regulating membranes for air filtration is dependent on the development of materials that exhibit a reversible stimuli-responsive pore size change. Here, by imbuing covalently crosslinked poly(ε-caprolactone) (cPCL) fibrous meshes with a reversible bidirectional shape-memory polymer actuation (rbSMPA) we create a material capable of temperature-controlled changes in porosity. Cyclic thermomechanical testing was used to characterize the mechanical properties of the meshes, which were composed of randomly arranged microfibers with diameters of 2.3 ± 0.6 μm giving an average pore size of approx. 10 μm. When subjected to programming strains of εm = 300% and 100% reversible strain changes of εʹrev = 22% ± 1% and 6% ± 1% were measured, with switching temperature ranges of 10 °C–30 °C and 45 °C–60 °C for heating and cooling, respectively. The rbSMPA of cPCL fibrous meshes generated a microscale reversible pore size change of 11% ± 3% (an average of 1.5 ± 0.6 μm), as measured by scanning electron microscopy. The incorporation of a two-way shape-memory actuation capability into fibrous meshes is anticipated to advance the development and application of smart membrane materials, creating commercially viable textiles and devices with enhanced performance and novel functionality.
KW  - reversible shape-memory effect
KW  - fiber meshes
KW  - electrospinning
Y1  - 2019
U6  - https://doi.org/10.1088/1361-665X/ab10a1
SN  - 0964-1726
SN  - 1361-665X
VL  - 28
IS  - 5
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Zhang, Pengfei
A1  - Rešetič, Andraž
A1  - Behl, Marc
A1  - Lendlein, Andreas
T1  - Multifunctionality in polymer networks by dynamic of coordination bonds
JF  - Macromolecular chemistry and physics
N2  - The need for multifunctional materials is driven by emerging technologies and innovations, such as in the field of soft robotics and tactile or haptic systems, where minimizing the number of operational components is not only desirable, but can also be essential for realizing such devices. This study report on designing a multifunctional soft polymer material that can address a number of operating requirements such as solvent resistance, reshaping ability, self-healing capability, fluorescence stimuli-responsivity, and anisotropic structural functions. The numerous functional abilities are associated to rhodium(I)-phosphine coordination bonds, which in a polymer network act with their dynamic and non-covalently bonded nature as multifunctional crosslinks. Reversible aggregation of coordination bonds leads to changes in fluorescence emission intensity that responds to chemical or mechanical stimuli. The fast dynamics and diffusion of rhodium-phosphine ions across and through contacting areas of the material provide for reshaping and self-healing abilities that can be further exploited for assembly of multiple pieces into complex forms, all without any loss to material-sensing capabilities.
KW  - assembly capabilities
KW  - fluorescence stimuli‐ responsivity
KW  - multiple functions
KW  - reshaping abilities
KW  - rhodium(I)– phosphine
KW  - coordination bonds
KW  - solvent resistance
Y1  - 2021
U6  - https://doi.org/10.1002/macp.202000394
SN  - 1521-3935
VL  - 222
IS  - 3
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Zhang, Pengfei
A1  - Behl, Marc
A1  - Peng, Xingzhou
A1  - Razzaq, Muhammad Yasar
A1  - Lendlein, Andreas
T1  - Ultrasonic Cavitation Induced Shape-Memory Effect in Porous Polymer Networks
JF  - Macromolecular rapid communications
N2  - Inspired by the application of ultrasonic cavitation based mechanical force (CMF) to open small channels in natural soft materials (skin or tissue), it is explored whether an artificial polymer network can be created, in which shape-changes can be induced by CMF. This concept comprises an interconnected macroporous rhodium-phosphine (Rh-P) coordination polymer network, in which a CMF can reversibly dissociate the Rh-P microphases. In this way, the ligand exchange of Rh-P coordination bonds in the polymer network is accelerated, resulting in a topological rearrangement of molecular switches. This rearrangement of molecular switches enables the polymer network to release internal tension under ultrasound exposure, resulting in a CMF-induced shape-memory capability. The interconnected macroporous structure with thin pore walls is essential for allowing the CMF to effectively permeate throughout the polymer network. Potential applications of this CMF-induced shape-memory polymer can be mechanosensors or ultrasound controlled switches.
Y1  - 2016
U6  - https://doi.org/10.1002/marc.201600439
SN  - 1022-1336
SN  - 1521-3927
VL  - 37
SP  - 1897
EP  - 1903
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Zhang, Pengfei
A1  - Behl, Marc
A1  - Peng, Xingzhou
A1  - Balk, Maria
A1  - Lendlein, Andreas
T1  - Chemoresponsive Shape-Memory Effect of Rhodium-Phosphine Coordination Polymer Networks
JF  - Chemistry of materials : a publication of the American Chemical Society
N2  - Chemoresponsive polymers are of technological significance for smart sensors or systems capable of molecular recognition. An important key requirement for these applications is the material’s structural integrity after stimulation. We explored whether covalently cross-linked metal ion–phosphine coordination polymers (MPN) can be shaped into any temporary shape and are capable of recovering from this upon chemoresponsive exposure to triphenylphosphine (Ph3P) ligands, whereas the MPN provide structural integrity. Depending on the metal-ion concentration used during synthesis of the MPN, the degree of swelling of the coordination polymer networks could be adjusted. Once the MPN was immersed into Ph3P solution, the reversible ligand-exchange reaction between the metal ions and the free Ph3P in solution causes a decrease of the coordination cross-link density in MPN again. The Ph3P-treated MPN was able to maintain its original shape, indicating a certain stability of shape even after stimulation. In this way, chemoresponsive control of the elastic properties (increase in volume and decrease of mechanical strength) of the MPN was demonstrated. This remarkable behavior motivated us to explore whether the MPN are capable of a chemoresponsive shape-memory effect. In initial experiments, shape fixity of around 60% and shape recovery of almost 90% were achieved when the MPN was exposed to Ph3P in case of rhodium. Potential applications for chemoresponsive shape-memory systems could be shapable semiconductors, e.g., for lighting or catalysts, which provide catalytic activity on demand.
Y1  - 2019
U6  - https://doi.org/10.1021/acs.chemmater.9b00363
SN  - 0897-4756
SN  - 1520-5002
VL  - 31
IS  - 15
SP  - 5402
EP  - 5407
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Zhang, Pengfei
A1  - Behl, Marc
A1  - Balk, Maria
A1  - Peng, Xingzhou
A1  - Lendlein, Andreas
T1  - Shape-programmable architectured hydrogels sensitive to ultrasound
JF  - Macromolecular rapid communications
N2  - On-demand motion of highly swollen polymer systems can be triggered by changes in pH, ion concentrations, or by heat. Here, shape-programmable, architectured hydrogels are introduced, which respond to ultrasonic-cavitation-based mechanical forces (CMF) by directed macroscopic movements. The concept is the implementation and sequential coupling of multiple functions (swellability in water, sensitivity to ultrasound, shape programmability, and shape-memory) in a semi-interpenetrating polymer network (s-IPN). The semi-IPN-based hydrogels are designed to function through rhodium coordination (Rh-s-IPNH). These coordination bonds act as temporary crosslinks. The porous hydrogels with coordination bonds (degree of swelling from 300 +/- 10 to 680 +/- 60) exhibit tensile strength sigma(max) up to 250 +/- 60 kPa. Shape fixity ratios up to 90% and shape recovery ratios up to 94% are reached. Potential applications are switches or mechanosensors.
KW  - cavitation-based mechanical force
KW  - rhodium-phosphine coordination bonds
KW  - semi-IPN hydrogels
KW  - shape-memory effect
Y1  - 2020
U6  - https://doi.org/10.1002/marc.201900658
SN  - 1022-1336
SN  - 1521-3927
VL  - 41
IS  - 7
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Zhang, Nan
A1  - Said, Andre
A1  - Wischke, Christian
A1  - Kral, Vivian
A1  - Brodwolf, Robert
A1  - Volz, Pierre
A1  - Boreham, Alexander
A1  - Gerecke, Christian
A1  - Li, Wenzhong
A1  - Neffe, Axel T.
A1  - Kleuser, Burkhard
A1  - Alexiev, Ulrike
A1  - Lendlein, Andreas
A1  - Schäfer-Korting, Monika
T1  - Poly[acrylonitrile-co-(N-vinyl pyrrolidone)] nanoparticles - Composition-dependent skin penetration enhancement of a dye probe and biocompatibility
JF  - European Journal of Pharmaceutics and Biopharmaceutics
N2  - Nanoparticles can improve topical drug delivery: size, surface properties and flexibility of polymer nanoparticles are defining its interaction with the skin. Only few studies have explored skin penetration for one series of structurally related polymer particles with systematic alteration of material composition. Here, a series of rigid poly[acrylonitrile-co-(N-vinyl pyrrolidone)] model nanoparticles stably loaded with Nile Red or Rhodamin B, respectively, was comprehensively studied for biocompatibility and functionality. Surface properties were altered by varying the molar content of hydrophilic NVP from 0 to 24.1% and particle size ranged from 35 to 244 nm. Whereas irritancy and genotoxicity were not revealed, lipophilic and hydrophilic nanoparticles taken up by keratinocytes affected cell viability. Skin absorption of the particles into viable skin ex vivo was studied using Nile Red as fluorescent probe. Whilst an intact stratum corneum efficiently prevented penetration, almost complete removal of the horny layer allowed nanoparticles of smaller size and hydrophilic particles to penetrate into viable epidermis and dermis. Hence, systematic variations of nanoparticle properties allows gaining insights into critical criteria for biocompatibility and functionality of novel nanocarriers for topical drug delivery and risks associated with environmental exposure.
KW  - Biocompatibility testing
KW  - Drug delivery systems
KW  - Nanoparticle
KW  - Poly[acrylonitrile-co-(N-vinyl pyrrolidone)]
KW  - Polymers
KW  - Skin absorption
Y1  - 2017
U6  - https://doi.org/10.1016/j.ejpb.2016.10.019
SN  - 0939-6411
SN  - 1873-3441
VL  - 116
SP  - 66
EP  - 75
PB  - Elsevier
CY  - Amsterdam
ER  -