TY - JOUR A1 - Li, Mingjun A1 - Gao, Lingyan A1 - Schlaich, Christoph A1 - Zhang, Jianguang A1 - Donskyi, Ievgen S. A1 - Yu, Guozhi A1 - Li, Wenzhong A1 - Tu, Zhaoxu A1 - Rolff, Jens A1 - Schwerdtle, Tanja A1 - Haag, Rainer A1 - Ma, Nan T1 - Construction of Functional Coatings with Durable and Broad-Spectrum Antibacterial Potential Based on Mussel-Inspired Dendritic Polyglycerol and in Situ-Formed Copper Nanoparticles JF - ACS applied materials & interfaces N2 - A novel surface coating with durable broad-spectrum antibacterial ability was prepared based on mussel inspired dendritic polyglycerol (MI-dPG) embedded with copper nanoparticles (Cu NPs). The functional surface coating is fabricated via a facile dip-coating process followed by in situ reduction of copper ions with a MI-dPG coating to introduce Cu NPs into the coating matrix. This coating has been demonstrated to possess efficient long-term antibacterial properties against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and kanamycin-resistant E. coli through an "attract-kill-release" strategy. The synergistic antibacterial activity of the coating was shown by the combination of two functions of the contact killing, reactive oxygen species production and Cu ions released from the coating. Furthermore, this coating inhibited biofilm formation and showed good compatibility to eukaryotic cells. Thus, this newly developed Cu NP-incorporated MI-dPG surface coating may find potential application in the design of antimicrobial coating, such as implantable devices. KW - Cu NP-incorporated MI-dPG coating KW - universal coating KW - in situ chemical reduction KW - antibacterial effect KW - drug-resistant bacteria Y1 - 2017 U6 - https://doi.org/10.1021/acsami.7b10541 SN - 1944-8244 VL - 9 SP - 35411 EP - 35418 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Li, Zhengdong A1 - Xu, Xun A1 - Wang, Weiwei A1 - Kratz, Karl A1 - Sun, Xianlei A1 - Zou, Jie A1 - Deng, Zijun A1 - Jung, Friedrich Wilhelm A1 - Gossen, Manfred A1 - Ma, Nan A1 - Lendlein, Andreas T1 - Modulation of the mesenchymal stem cell migration capacity via preconditioning with topographic microstructure JF - Clinical hemorheology and microcirculation : blood flow and vessels N2 - Controlling mesenchymal stem cells (MSCs) behavior is necessary to fully exploit their therapeutic potential. Various approaches are employed to effectively influence the migration capacity of MSCs. Here, topographic microstructures with different microscale roughness were created on polystyrene (PS) culture vessel surfaces as a feasible physical preconditioning strategy to modulate MSC migration. By analyzing trajectories of cells migrating after reseeding, we demonstrated that the mobilization velocity of human adipose derived mesenchymal stem cells (hADSCs) could be promoted by and persisted after brief preconditioning with the appropriate microtopography. Moreover, the elevated activation levels of focal adhesion kinase (FAK) and mitogen-activated protein kinase (MAPK) in hADSCs were also observed during and after the preconditioning process. These findings underline the potential enhancement of in vivo therapeutic efficacy in regenerative medicine via transplantation of topographic microstructure preconditioned stem cells. KW - Mesenchymal stem cells KW - precondition KW - microstructure KW - migration KW - FAK-MAPK Y1 - 2017 U6 - https://doi.org/10.3233/CH-179208 SN - 1386-0291 SN - 1875-8622 VL - 67 SP - 267 EP - 278 PB - IOS Press CY - Amsterdam ER - 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 - Wang, Weiwei A1 - Xu, Xun A1 - Li, Zhengdong A1 - Kratz, Karl A1 - Ma, Nan A1 - Lendlein, Andreas T1 - Modulating human mesenchymal stem cells using poly(n-butyl acrylate) networks in vitro with elasticity matching human arteries JF - Clinical hemorheology and microcirculation : blood flow and vessels N2 - Non-swelling hydrophobic poly(n-butyl acrylate) network (cPnBA) is a candidate material for synthetic vascular grafts owing to its low toxicity and tailorable mechanical properties. Mesenchymal stem cells (MSCs) are an attractive cell type for accelerating endothelialization because of their superior anti-thrombosis and immune modulatory function. Further, they can differentiate into smooth muscle cells or endothelial-like cells and secret pro-angiogenic factors such as vascular endothelial growth factor (VEGF). MSCs are sensitive to the substrate mechanical properties, with the alteration of their major cellular behavior and functions as a response to substrate elasticity. Here, we cultured human adipose-derived mesenchymal stem cells (hADSCs) on cPnBAs with different mechanical properties (cPnBA250, Young’s modulus (E) = 250 kPa; cPnBA1100, E = 1100 kPa) matching the elasticity of native arteries, and investigated their cellular response to the materials including cell attachment, proliferation, viability, apoptosis, senescence and secretion. The cPnBA allowed high cell attachment and showed negligible cytotoxicity. F-actin assembly of hADSCs decreased on cPnBA films compared to classical tissue culture plate. The difference of cPnBA elasticity did not show dramatic effects on cell attachment, morphology, cytoskeleton assembly, apoptosis and senescence. Cells on cPnBA250, with lower proliferation rate, had significantly higher VEGF secretion activity. These results demonstrated that tuning polymer elasticity to regulate human stem cells might be a potential strategy for constructing stem cell-based artificial blood vessels. KW - Poly(n-butyl acrylate) KW - mechanical property KW - vascular graft KW - mesenchymal stem cells KW - VEGF Y1 - 2019 U6 - https://doi.org/10.3233/CH-189418 SN - 1386-0291 SN - 1875-8622 VL - 71 IS - 2 SP - 277 EP - 289 PB - IOS Press CY - Amsterdam ER - TY - JOUR A1 - Wang, Weiwei A1 - Kratz, Karl A1 - Behl, Marc A1 - Yan, Wan A1 - Liu, Yue A1 - Xu, Xun A1 - Baudis, Stefan A1 - Li, Zhengdong A1 - Kurtz, Andreas A1 - Lendlein, Andreas A1 - Ma, Nan T1 - The interaction of adipose-derived human mesenchymal stem cells and polyether ether ketone JF - Clinical hemorheology and microcirculation : blood flow and vessels N2 - Polyether ether ketone (PEEK) as a high-performance, thermoplastic implant material entered the field of medical applications due to its structural function and commercial availability. In bone tissue engineering, the combination of mesenchymal stem cells (MSCs) with PEEK implants may accelerate the bone formation and promote the osseointegration between the implant and the adjacent bone tissue. In this concept the question how PEEK influences the behaviour and functions of MSCs is of great interest. Here the cellular response of human adipose-derived MSCs to PEEK was evaluated and compared to tissue culture plate (TCP) as the reference material. Viability and morphology of cells were not altered when cultured on the PEEK film. The cells on PEEK presented a high proliferation activity in spite of a relatively lower initial cell adhesion rate. There was no significant difference on cell apoptosis and senescence between the cells on PEEK and TCP. The inflammatory cytokines and VEGF secreted by the cells on these two surfaces were at similar levels. The cells on PEEK showed up-regulated BMP2 and down-regulated BMP4 and BMP6 gene expression, whereas no conspicuous differences were observed in the committed osteoblast markers (BGLAP, COL1A1 and Runx2). With osteoinduction the cells on PEEK and TCP exhibited a similar osteogenic differentiation potential. Our results demonstrate the biofunctionality of PEEK for human MSC cultivation and differentiation. Its clinical benefits in bone tissue engineering may be achieved by combining MSCs with PEEK implants. These data may also provide useful information for further modification of PEEK with chemical or physical methods to regulate the cellular processes of MSCs and to consequently improve the efficacy of MSC-PEEK based therapies. KW - Polyether ether ketone KW - mesenchymal stem cells KW - biocompatibility KW - cell-material interaction KW - osteogenic differentiation Y1 - 2015 U6 - https://doi.org/10.3233/CH-152001 SN - 1386-0291 SN - 1875-8622 VL - 61 IS - 2 SP - 301 EP - 321 PB - IOS Press CY - Amsterdam 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 - TY - JOUR A1 - Stefancu, Andrei A1 - Nan, Lin A1 - Zhu, Li A1 - Chis, Vasile A1 - Bald, Ilko A1 - Liu, Min A1 - Leopold, Nicolae A1 - Maier, Stefan A. A1 - Cortes, Emiliano T1 - Controlling plasmonic chemistry pathways through specific ion effects JF - Advanced optical materials N2 - Plasmon-driven dehalogenation of brominated purines has been recently explored as a model system to understand fundamental aspects of plasmon-assisted chemical reactions. Here, it is shown that divalent Ca2+ ions strongly bridge the adsorption of bromoadenine (Br-Ade) to Ag surfaces. Such ion-mediated binding increases the molecule's adsorption energy leading to an overlap of the metal energy states and the molecular states, enabling the chemical interface damping (CID) of the plasmon modes of the Ag nanostructures (i.e., direct electron transfer from the metal to Br-Ade). Consequently, the conversion of Br-Ade to adenine almost doubles following the addition of Ca2+. These experimental results, supported by theoretical calculations of the local density of states of the Ag/Br-Ade complex, indicate a change of the charge transfer pathway driving the dehalogenation reaction, from Landau damping (in the lack of Ca2+ ions) to CID (after the addition of Ca2+). The results show that the surface dynamics of chemical species (including water molecules) play an essential role in charge transfer at plasmonic interfaces and cannot be ignored. It is envisioned that these results will help in designing more efficient nanoreactors, harnessing the full potential of plasmon-assisted chemistry. KW - chemical interface damping KW - Hofmeister effect KW - hydration layer KW - plasmonic chemistry KW - specific ion effects KW - surface-enhanced Raman scattering Y1 - 2022 U6 - https://doi.org/10.1002/adom.202200397 SN - 2195-1071 VL - 10 IS - 14 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Li, Nan A1 - Wang, Suiping A1 - Mo, Luxi A1 - Kliegl, Reinhold T1 - Contextual constraint and preview time modulate the semantic preview effect BT - evidence from Chinese sentence reading JF - The quarterly journal of experimental psychology N2 - Word recognition in sentence reading is influenced by information from both preview and context. Recently, semantic preview effect (SPE) was observed being modulated by the constraint of context, indicating that context might accelerate the processing of semantically related preview words. Besides, SPE was found to depend on preview time, which suggests that SPE may change with different processing stages of preview words. Therefore, it raises the question of whether preview time-dependent SPE would be modulated by contextual constraint. In this study, we not only investigated the impact of contextual constraint on SPE in Chinese reading but also examined its dependency on preview time. The preview word and the target word were identical, semantically related or unrelated to the target word. The results showed a significant three-way interaction: The SPE depended on contextual constraint and preview time. In separate analyses for low and high contextual constraint of target words, the SPE significantly decreased with an increase in preview duration when the target word was of low constraint in the sentence. The effect was numerically in the same direction but weaker and statistically nonsignificant when the target word was highly constrained in the sentence. The results indicate that word processing in sentences is a dynamic process of integrating information from both preview (bottom-up) and context (top-down). KW - Semantic preview benefit KW - contextual constraint KW - word process KW - reading Y1 - 2018 U6 - https://doi.org/10.1080/17470218.2017.1310914 SN - 1747-0218 SN - 1747-0226 VL - 71 IS - 1 SP - 241 EP - 249 PB - Sage Publ. CY - London ER -