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- ItemIn-Gel Direct Laser Writing for 3D-Designed Hydrogel Composites That Undergo Complex Self-Shaping(Weinheim : Wiley-VCH, 2017) Nishiguchi, Akihiro; Mourran, Ahmed; Zhang, Hang; Möller, MartinSelf-shaping and actuating materials inspired by biological system have enormous potential for biosensor, microrobotics, and optics. However, the control of 3D-complex microactuation is still challenging due to the difficulty in design of nonuniform internal stress of micro/nanostructures. Here, we develop in-gel direct laser writing (in-gel DLW) procedure offering a high resolution inscription whereby the two materials, resin and hydrogel, are interpenetrated on a scale smaller than the wavelength of the light. The 3D position and mechanical properties of the inscribed structures could be tailored to a resolution better than 100 nm over a wide density range. These provide an unparalleled means of inscribing a freely suspended microstructures of a second material like a skeleton into the hydrogel body and also to direct isotropic volume changes to bending and distortion motions. In the combination with a thermosensitive hydrogel rather small temperature variations could actuate large amplitude motions. This generates complex modes of motion through the rational engineering of the stresses present in the multicomponent material. More sophisticated folding design would realize a multiple, programmable actuation of soft materials. This method inspired by biological system may offer the possibility for functional soft materials capable of biomimetic actuation and photonic crystal application.
- ItemDNA Nanotechnology Enters Cell Membranes(Weinheim : Wiley-VCH, 2019) Huo, Shuaidong; Li, Hongyan; Boersma, Arnold J.; Herrmann, AndreasDNA is more than a carrier of genetic information: It is a highly versatile structural motif for the assembly of nanostructures, giving rise to a wide range of functionalities. In this regard, the structure programmability is the main advantage of DNA over peptides, proteins, and small molecules. DNA amphiphiles, in which DNA is covalently bound to synthetic hydrophobic moieties, allow interactions of DNA nanostructures with artificial lipid bilayers and cell membranes. These structures have seen rapid growth with great potential for medical applications. In this Review, the current state of the art of the synthesis of DNA amphiphiles and their assembly into nanostructures are first summarized. Next, an overview on the interaction of these DNA amphiphiles with membranes is provided, detailing on the driving forces and the stability of the interaction. Moreover, the interaction with cell surfaces in respect to therapeutics, biological sensing, and cell membrane engineering is highlighted. Finally, the challenges and an outlook on this promising class of DNA hybrid materials are discussed.
- ItemA physicochemical perspective of aging from single-cell analysis of ph, macromolecular and organellar crowding in yeast(Cambridge : eLife Sciences Publications, 2020) Mouton, Sara N.; Thaller, David J.; Crane, Matthew M.; Rempel, Irina L.; Terpstra, Owen T.; Steen, Anton; Kaeberlein, Matt; Lusk, C. Patrick; Boersma, Arnold J.; Veenhoff, Liesbeth M.Cellular aging is a multifactorial process that is characterized by a decline in homeostatic capacity, best described at the molecular level. Physicochemical properties such as pH and macromolecular crowding are essential to all molecular processes in cells and require maintenance. Whether a drift in physicochemical properties contributes to the overall decline of homeostasis in aging is not known. Here we show that the cytosol of yeast cells acidifies modestly in early aging and sharply after senescence. Using a macromolecular crowding sensor optimized for long-term FRET measurements, we show that crowding is rather stable and that the stability of crowding is a stronger predictor for lifespan than the absolute crowding levels. Additionally, in aged cells we observe drastic changes in organellar volume, leading to crowding on the µm scale, which we term organellar crowding. Our measurements provide an initial framework of physicochemical parameters of replicatively aged yeast cells. © 2020, eLife Sciences Publications Ltd. All rights reserved.
- ItemGuiding cell adhesion and motility by modulating cross-linking and topographic properties of microgel arrays(San Francisco, California, US : PLOS, 2021) Riegert, Janine; Töpel, Alexander; Schieren, Jana; Coryn, Renee; Dibenedetto, Stella; Braunmiller, Dominik; Zajt, Kamil; Schalla, Carmen; Rütten, Stephan; Zenke, Martin; Pich, Andrij; Sechi, Antonio; Blank, Kerstin G.Biomaterial-driven modulation of cell adhesion and migration is a challenging aspect of tissue engineering. Here, we investigated the impact of surface-bound microgel arrays with variable geometry and adjustable cross-linking properties on cell adhesion and migration. We show that cell migration is inversely correlated with microgel array spacing, whereas directionality increases as array spacing increases. Focal adhesion dynamics is also modulated by microgel topography resulting in less dynamic focal adhesions on surface-bound microgels. Microgels also modulate the motility and adhesion of Sertoli cells used as a model for cell migration and adhesion. Both focal adhesion dynamics and speed are reduced on microgels. Interestingly, Gas2L1, a component of the cytoskeleton that mediates the interaction between microtubules and microfilaments, is dispensable for the regulation of cell adhesion and migration on microgels. Finally, increasing microgel cross-linking causes a clear reduction of focal adhesion turnover in Sertoli cells. These findings not only show that spacing and rigidity of surface-grafted microgels arrays can be effectively used to modulate cell adhesion and motility of diverse cellular systems, but they also form the basis for future developments in the fields of medicine and tissue engineering.
- ItemSafe and efficient 2D molybdenum disulfide platform for cooperative imaging-guided photothermal-selective chemotherapy: A preclinical study(Amsterdam [u.a.] : Elsevier, 2021) Li, Xin; Kong, Lingdan; Hu, Wei; Zhang, Changchang; Pich, Andrij; Shi, Xiangyang; Wang, Xipeng; Xing, LingxiIntroduction: The striking imbalance between the ever-increasing amount of nanomedicines and low clinical translation of products has become the focus of intense debate. For clinical translation, the critical issue is to select the appropriate agents and combination regimen for targeted diseases, not to prepare increasingly complex nanoplatforms. Objectives: A safe and efficient platform, α-tocopheryl succinate (α-TOS) married 2D molybdenum disulfide, was devised by a facile method and applied for cooperative imaging-guided photothermal-selective chemotherapy of ovarian carcinoma. Methods: A novel platform of PEGylated α-TOS and folic acid (FA) conjugated 2D MoS2 nanoflakes was fabricated for the cooperative multimode computed tomography (CT)/photoacoustic (PA)/thermal imaging-guided photothermal-selective chemotherapy of ovarian carcinoma. Results: The photothermal efficiency (65.3%) of the platform under safe near-infrared irradiation is much higher than that of other photothermal materials reported elsewhere. Moreover, the covalently linked α-TOS renders platform with selective chemotherapy for cancer cells. Remarkably, with these excellent properties, the platform can be used to completely eliminate the solid tumor by safe photothermal therapy, and then kill the residual cancer cells by selective chemotherapy to prevent tumor recurrence. More significantly, barely side effects occur in the whole treatment process. The excellent efficacy and safety benefits in vivo lead to the prominent survival rate of 100% over 91 days. Conclusion: The safe and efficient platform might be a candidate of clinical nanomedicines for multimode theranostics. This study demonstrates an innovative thought in precise nanomedicine regarding the design of next generation of cancer theranostic protocol for potential clinical practice.
- ItemCubosomes from hierarchical self-assembly of poly(ionic liquid) block copolymers([London] : Nature Publishing Group UK, 2017) He, Hongkun; Rahimi, Khosrow; Zhong, Mingjiang; Mourran, Ahmed; Luebke, David R.; Nulwala, Hunaid B.; Möller, Martin; Matyjaszewski, KrzysztofCubosomes are micro- and nanoparticles with a bicontinuous cubic two-phase structure, reported for the self-assembly of low molecular weight surfactants, for example, lipids, but rarely formed by polymers. These objects are characterized by a maximum continuous interface and high interface to volume ratio, which makes them promising candidates for efficient adsorbents and host-guest applications. Here we demonstrate self-assembly to nanoscale cuboidal particles with a bicontinuous cubic structure by amphiphilic poly(ionic liquid) diblock copolymers, poly(acrylic acid)-block-poly(4-vinylbenzyl)-3-butyl imidazolium bis(trifluoromethylsulfonyl)imide, in a mixture of tetrahydrofuran and water under optimized conditions. Structure determining parameters include polymer composition and concentration, temperature, and the variation of the solvent mixture. The formation of the cubosomes can be explained by the hierarchical interactions of the constituent components. The lattice structure of the block copolymers can be transferred to the shape of the particle as it is common for atomic and molecular faceted crystals.
- ItemUltra-strong bio-glue from genetically engineered polypeptides([London] : Nature Publishing Group UK, 2021) Ma, Chao; Sun, Jing; Li, Bo; Feng, Yang; Sun, Yao; Xiang, Li; Wu, Baiheng; Xiao, Lingling; Liu, Baimei; Petrovskii, Vladislav S.; Zhang, Jinrui; Wang, Zili; Li, Hongyan; Zhang, Lei; Li, Jingjing; Wang, Fan; Gӧstl, Robert; Potemkin, Igor I.; Chen, Dong; Zeng, Hongbo; Zhang, Hongjie; Liu, Kai; Herrmann, AndreasThe development of biomedical glues is an important, yet challenging task as seemingly mutually exclusive properties need to be combined in one material, i.e. strong adhesion and adaption to remodeling processes in healing tissue. Here, we report a biocompatible and biodegradable protein-based adhesive with high adhesion strengths. The maximum strength reaches 16.5 ± 2.2 MPa on hard substrates, which is comparable to that of commercial cyanoacrylate superglue and higher than other protein-based adhesives by at least one order of magnitude. Moreover, the strong adhesion on soft tissues qualifies the adhesive as biomedical glue outperforming some commercial products. Robust mechanical properties are realized without covalent bond formation during the adhesion process. A complex consisting of cationic supercharged polypeptides and anionic aromatic surfactants with lysine to surfactant molar ratio of 1:0.9 is driven by multiple supramolecular interactions enabling such strong adhesion. We demonstrate the glue’s robust performance in vitro and in vivo for cosmetic and hemostasis applications and accelerated wound healing by comparison to surgical wound closures.
- ItemExploring the colloid-to-polymer transition for ultra-low crosslinked microgels from three to two dimensions([London] : Nature Publishing Group UK, 2019) Scotti, A.; Bochenek, S.; Brugnoni, M.; Fernandez-Rodriguez, M.A.; Schulte, M.F.; Houston, J.E.; Gelissen, A.P.H.; Potemkin, I.I.; Isa, L.; Richtering, W.Microgels are solvent-swollen nano- and microparticles that show prevalent colloidal-like behavior despite their polymeric nature. Here we study ultra-low crosslinked poly(N-isopropylacrylamide) microgels (ULC), which can behave like colloids or flexible polymers depending on dimensionality, compression or other external stimuli. Small-angle neutron scattering shows that the structure of the ULC microgels in bulk aqueous solution is characterized by a density profile that decays smoothly from the center to a fuzzy surface. Their phase behavior and rheological properties are those of soft colloids. However, when these microgels are confined at an oil-water interface, their behavior resembles that of flexible macromolecules. Once monolayers of ultra-low crosslinked microgels are compressed, deposited on solid substrate and studied with atomic-force microscopy, a concentration-dependent topography is observed. Depending on the compression, these microgels can behave as flexible polymers, covering the substrate with a uniform film, or as colloidal microgels leading to a monolayer of particles.
- ItemBio-degradable highly fluorescent conjugated polymer nanoparticles for bio-medical imaging applications([London] : Nature Publishing Group UK, 2017) Repenko, Tatjana; Rix, Anne; Ludwanowski, Simon; Go, Dennis; Kiessling, Fabian; Lederle, Wiltrud; Kuehne, Alexander J. C.Conjugated polymer nanoparticles exhibit strong fluorescence and have been applied for biological fluorescence imaging in cell culture and in small animals. However, conjugated polymer particles are hydrophobic and often chemically inert materials with diameters ranging from below 50 nm to several microns. As such, conjugated polymer nanoparticles cannot be excreted through the renal system. This drawback has prevented their application for clinical bio-medical imaging. Here, we present fully conjugated polymer nanoparticles based on imidazole units. These nanoparticles can be bio-degraded by activated macrophages. Reactive oxygen species induce scission of the conjugated polymer backbone at the imidazole unit, leading to complete decomposition of the particles into soluble low molecular weight fragments. Furthermore, the nanoparticles can be surface functionalized for directed targeting. The approach opens a wide range of opportunities for conjugated polymer particles in the fields of medical imaging, drug-delivery, and theranostics.
- ItemGuidance of mesenchymal stem cells on fibronectin structured hydrogel films(San Francisco, California, US : PLOS, 2014) Kasten, Annika; Naser, Tamara; Brüllhoff, Kristina; Fiedler, Jörg; Müller, Petra; Möller, Martin; Rychly, Joachim; Groll, Jürgen; Brenner, Rolf E.; Engler, Adam J.Designing of implant surfaces using a suitable ligand for cell adhesion to stimulate specific biological responses of stem cells will boost the application of regenerative implants. For example, materials that facilitate rapid and guided migration of stem cells would promote tissue regeneration. When seeded on fibronectin (FN) that was homogeneously immmobilized to NCO-sP(EO-stat-PO), which otherwise prevents protein binding and cell adhesion, human mesenchymal stem cells (MSC) revealed a faster migration, increased spreading and a more rapid organization of different cellular components for cell adhesion on fibronectin than on a glass surface. To further explore, how a structural organization of FN controls the behavior of MSC, adhesive lines of FN with varying width between 10 µm and 80 µm and spacings between 5 µm and 20 µm that did not allow cell adhesion were generated. In dependance on both line width and gaps, cells formed adjacent cell contacts, were individually organized in lines, or bridged the lines. With decreasing sizes of FN lines, speed and directionality of cell migration increased, which correlated with organization of the actin cytoskeleton, size and shape of the nuclei as well as of focal adhesions. Together, defined FN lines and gaps enabled a fine tuning of the structural organization of cellular components and migration. Microstructured adhesive substrates can mimic the extracellular matrix in vivo and stimulate cellular mechanisms which play a role in tissue regeneration.