Electron Beam-Modified Collagen Type I Fibers: Synthesis and Characterization of Mechanical Response.

Ten MeV electron beam treatment facilitates a biomimetic introduction of cross-links in collagenous biopolymer systems, modifying their viscoelastic properties, mechanical stability, and swelling behavior. For reconstituted collagen type I fibers, electron-induced cross-linking opens up new perspectives regarding future biomedical applications in terms of tissue and ligament engineering. We demonstrate how electron irradiation affects stiffness both in low-strain regimes and in postyield regimes of biocompatible reconstituted rat tail collagen type I fibers. Stress-strain tests show a dose-dependent increase in modulus in the nonlinear elastic response, indicating a central role of induced cross-links in mechanical stability. Environmental scanning electron microscopy after fiber rupture reveals aligned distributed collagen fibril domains under the fiber surface for as-prepared fibers, accompanied by a ductile fracture behavior, whereas, in tensile tests imaged by light microscopy after 10 MeV electron treatment, isotropic network topologies are observed until the occurrence of a brittle type of rupture. Based on the biomimicry of the process, these findings might pave the way for a novel type of synthesis of tailored tendon or ligament substitutes.

Rapid prototyping of microfluidic chips enabling controlled biotechnology applications in microspace.

Rapid prototyping of microfluidic chips is a key enabler for controlled biotechnology applications in microspaces, as it allows for the efficient design and production of microfluidic systems. With rapid prototyping, researchers and engineers can quickly create and test new microfluidic chip designs, which can then be optimized for specific applications in biotechnology. One of the key advantages of microfluidic chips for biotechnology is the ability to manipulate and control biological samples in a microspace, which enables precise and controlled experiments under well-defined conditions. This is particularly useful for applications such as cell culture, drug discovery, and diagnostic assays, where precise control over the biological environment is crucial for obtaining accurate results. Established methods, for example, soft lithography, 3D printing, injection molding, as well as other recently highlighted innovative approaches, will be compared and challenges as well as limitations will be discussed. It will be shown that rapid prototyping of microfluidic chips enables the use of advanced materials and technologies, such as smart materials and digital sensors, which can further enhance the capabilities of microfluidic systems for biotechnology applications. Overall, rapid prototyping of microfluidic chips is an important enabling technology for controlled biotechnology applications in microspaces, as well as for upscaling it into macroscopic bioreactors, and its continued development and improvement will play a critical role in advancing the field. The review will highlight recent trends in terms of materials and competing approaches and shed light on current challenges on the way toward integrated microtechnologies. Also, the possibility to easy and direct implementation of novel functions (membranes, functionalization of interfaces, etc.) is discussed.

Energetic Electron-Assisted Synthesis of Tailored Magnetite (Fe3O4) and Maghemite (γ-Fe2O3) Nanoparticles: Structure and Magnetic Properties.

Iron oxide nanoparticles with a mean size of approximately 5 nm were synthesized by irradiating micro-emulsions containing iron salts with energetic electrons. The properties of the nanoparticles were investigated using scanning electron microscopy, high-resolution transmission electron microscopy, selective area diffraction and vibrating sample magnetometry. It was found that formation of superparamagnetic nanoparticles begins at a dose of 50 kGy, though these particles show low crystallinity, and a higher portion is amorphous. With increasing doses, an increasing crystallinity and yield could be observed, which is reflected in an increasing saturation magnetization. The blocking temperature and effective anisotropy constant were determined via zero-field cooling and field cooling measurements. The particles tend to form clusters with a size of 34 nm to 73 nm. Magnetite/maghemite nanoparticles could be identified via selective area electron diffraction patterns. Additionally, goethite nanowires could be observed.

Laminin Adsorption and Adhesion of Neurons and Glial Cells on Carbon Implanted Titania Nanotube Scaffolds for Neural Implant Applications.

Interfacing neurons persistently to conductive matter constitutes one of the key challenges when designing brain-machine interfaces such as neuroelectrodes or retinal implants. Novel materials approaches that prevent occurrence of loss of long-term adhesion, rejection reactions, and glial scarring are highly desirable. Ion doped titania nanotube scaffolds are a promising material to fulfill all these requirements while revealing sufficient electrical conductivity, and are scrutinized in the present study regarding their neuron-material interface. Adsorption of laminin, an essential extracellular matrix protein of the brain, is comprehensively analyzed. The implantation-dependent decline in laminin adsorption is revealed by employing surface characteristics such as nanotube diameter, ζ-potential, and surface free energy. Moreover, the viability of U87-MG glial cells and SH-SY5Y neurons after one and four days are investigated, as well as the material's cytotoxicity. The higher conductivity related to carbon implantation does not affect the viability of neurons, although it impedes glial cell proliferation. This gives rise to novel titania nanotube based implant materials with long-term stability, and could reduce undesirable glial scarring.

Electron beam treated injectable agarose/alginate beads prepared by electrospraying.

Granular hydrogels have evolved into an innovative technology for biomedicine. Unlike conventional hydrogels, granular hydrogels display dynamic properties like injectability and porosity, making them feasible for applications in 3D bioprinting and tissue engineering. High-energy electron irradiation combines sterilization and tuning of hydrogel properties without adding potentially cytotoxic chemicals. In this study, granular agarose/alginate hydrogels are prepared by electrospraying. Utilizing 10 MeV electron irradiation, the granular hydrogels are treated in a dose range of 0 kGy-30 kGy relevant for sterilization. Herein, a size reduction of the microparticles is observed. Mechanical properties of individual agarose/alginate beads are examined using AFM measurements revealing a gel softening attributed to radiation induced chain scission. Shear-thinning and self-healing characteristics of the entire granular hydrogel are studied employing rheology. Although viscoelasticity changes under irradiation, shear-thinning and self-healing prevails. These dynamic properties enable injection, which is demonstrated for 27 G needles. This study presents a mechanical characterization of high-energy electron irradiated granular agarose/alginate hydrogels that extends the diversity of available injectable hydrogels and provides a basis for biomedical applications of this scaffold.

Structural Breakdown of Collagen Type I Elastin Blend Polymerization.

Biopolymer blends are advantageous materials with novel properties that may show performances way beyond their individual constituents. Collagen elastin hybrid gels are a new representative of such materials as they employ elastin's thermo switching behavior in the physiological temperature regime. Although recent studies highlight the potential applications of such systems, little is known about the interaction of collagen and elastin fibers during polymerization. In fact, the final network structure is predetermined in the early and mostly arbitrary association of the fibers. We investigated type I collagen polymerized with bovine neck ligament elastin with up to 33.3 weight percent elastin and showed, by using a plate reader, zeta potential and laser scanning microscopy (LSM) experiments, that elastin fibers bind in a lateral manner to collagen fibers. Our plate reader experiments revealed an elastin concentration-dependent increase in the polymerization rate, although the rate increase was greatest at intermediate elastin concentrations. As elastin does not significantly change the structural metrics pore size, fiber thickness or 2D anisotropy of the final gel, we are confident to conclude that elastin is incorporated homogeneously into the collagen fibers.

From Strain Stiffening to Softening-Rheological Characterization of Keratins 8 and 18 Networks Crosslinked via Electron Irradiation.

Networks of crosslinked keratin filaments are abundant in epithelial cells and tissues, providing resilience against mechanical forces and ensuring cellular integrity. Although studies of in vitro models of reconstituted keratin networks have revealed important mechanical aspects, the mechanical properties of crosslinked keratin structures remain poorly understood. Here, we exploited the power of electron beam irradiation (EBI) to crosslink in vitro networks of soft epithelial keratins 8 and 18 (k8-k18) filaments with different irradiation doses (30 kGy, 50 kGy, 80 kGy, 100 kGy, and 150 kGy). We combined bulk shear rheology with confocal microscopy to investigate the impact of crosslinking on the mechanical and structural properties of the resultant keratin gels. We found that irradiated keratin gels display higher linear elastic modulus than the unirradiated, entangled networks at all doses tested. However, at the high doses (80 kGy, 100 kGy, and 150 kGy), we observed a remarkable drop in the elastic modulus compared to 50 kGy. Intriguingly, the irradiation drastically changed the behavior for large, nonlinear deformations. While untreated keratin networks displayed a strong strain stiffening, increasing irradiation doses shifted the system to a strain softening behavior. In agreement with the rheological behavior in the linear regime, the confocal microscopy images revealed fully isotropic networks with high percolation in 30 kGy and 50 kGy-treated keratin samples, while irradiation with 100 kGy induced the formation of thick bundles and clusters. Our results demonstrate the impact of permanent crosslinking on k8-k18 mechanics and provide new insights into the potential contribution of intracellular covalent crosslinking to the loss of mechanical resilience in some human keratin diseases. These insights will also provide inspiration for the synthesis of new keratin-based biomaterials.

Biomimetic crosslinking of collagen gels by energetic electrons: The role of L-lysine.

Energetic electrons have recently evolved as a powerful tool for crosslinking bio-derived hydrogels without the need for adding potentially hazardous reagents. Application of this approach allows for synthesis of biomimetic collagen-derived networks of highly tunable properties and functionalization. Yet, the underlying reaction kinetics are still not sufficiently established at this point. While hydroxyl radicals are generated by energetic electron-induced hydrolysis of water and play a key role in introducing covalent bonds between network fibers, a detailed mechanistic understanding would significantly increase applicability. We present a comprehensive analysis of central aspects of the reactivity between the hydroxyl radical (•OH) and collagen, elastin, glycine (Gly) and l-lysine (Lys). Pulse radiolysis (PR), solid state nuclear magnetic resonance (NMR), ultraviolet-visible absorption spectroscopy (UV/VIS) and electron spray ionization mass spectrometry (ESI-MS) shine light on distinct features of the crosslinking process. These highlight retained protein backbone integrity in collagen and elastin whilst Lys's ability to form several imine bonded Lys-Lys-species suggests striking similarities to crosslinking via lysyl oxidase catalysis in vivo. Thus, energetic electron based crosslinking opens the venue for customized hybrid gels of outstanding biomimicry and -compatibility. STATEMENT OF SIGNIFICANCE: Energetic electron beam treatment constitutes a highly attractive approach to establish chemical bonds between (bio) molecules. Although a convincing number of publications showed the versatility regarding crosslinking of bioderived hydrogels, insights into the underlying chemistry are still unestablished at this point. The present work unravels the mechanistics of energetic electron induced processes in collagen and elastin hydrogels as well as several abundant amino acids in aqueous solution. As key finding we demonstrate, that i) the connection between polymer chains is dominated by amino acid side chain interaction and ii) two single l-lysine molecules form an imine bond between the terminal amino group of one molecule and the delta carbon of the second molecule. We also consider the formation of H-bonds as a second crosslinking pathway. These findings open up for advanced, optionally spatially resolved biomaterials design.

A study on the material properties of novel PEGDA/gelatin hybrid hydrogels polymerized by electron beam irradiation.

Gelatin-based hydrogels are highly desirable biomaterials for use in wound dressing, drug delivery, and extracellular matrix components due to their biocompatibility and biodegradability. However, insufficient and uncontrollable mechanical properties and degradation are the major obstacles to their application in medical materials. Herein, we present a simple but efficient strategy for a novel hydrogel by incorporating the synthetic hydrogel monomer polyethylene glycol diacrylate (PEGDA, offering high mechanical stability) into a biological hydrogel compound (gelatin) to provide stable mechanical properties and biocompatibility at the resulting hybrid hydrogel. In the present work, PEGDA/gelatin hybrid hydrogels were prepared by electron irradiation as a reagent-free crosslinking technology and without using chemical crosslinkers, which carry the risk of releasing toxic byproducts into the material. The viscoelasticity, swelling behavior, thermal stability, and molecular structure of synthesized hybrid hydrogels of different compound ratios and irradiation doses were investigated. Compared with the pure gelatin hydrogel, 21/9 wt./wt. % PEGDA/gelatin hydrogels at 6 kGy exhibited approximately up to 1078% higher storage modulus than a pure gelatin hydrogel, and furthermore, it turned out that the mechanical stability increased with increasing irradiation dose. The chemical structure of the hybrid hydrogels was analyzed by Fourier-transform infrared (FTIR) spectroscopy, and it was confirmed that both compounds, PEGDA and gelatin, were equally present. Scanning electron microscopy images of the samples showed fracture patterns that confirmed the findings of viscoelasticity increasing with gelatin concentration. Infrared microspectroscopy images showed that gelatin and PEGDA polymer fractions were homogeneously mixed and a uniform hybrid material was obtained after electron beam synthesis. In short, this study demonstrates that both the presence of PEGDA improved the material properties of PEGDA/gelatin hybrid hydrogels and the resulting properties are fine-tuned by varying the irradiation dose and PEGDA/gelatin concentration.

Electron Beam-Treated Enzymatically Mineralized Gelatin Hydrogels for Bone Tissue Engineering.

Biological hydrogels are highly promising materials for bone tissue engineering (BTE) due to their high biocompatibility and biomimetic characteristics. However, for advanced and customized BTE, precise tools for material stabilization and tuning material properties are desired while optimal mineralisation must be ensured. Therefore, reagent-free crosslinking techniques such as high energy electron beam treatment promise effective material modifications without formation of cytotoxic by-products. In the case of the hydrogel gelatin, electron beam crosslinking further induces thermal stability enabling biomedical application at physiological temperatures. In the case of enzymatic mineralisation, induced by Alkaline Phosphatase (ALP) and mediated by Calcium Glycerophosphate (CaGP), it is necessary to investigate if electron beam treatment before mineralisation has an influence on the enzymatic activity and thus affects the mineralisation process. The presented study investigates electron beam-treated gelatin hydrogels with previously incorporated ALP and successive mineralisation via incubation in a medium containing CaGP. It could be shown that electron beam treatment optimally maintains enzymatic activity of ALP which allows mineralisation. Furthermore, the precise tuning of material properties such as increasing compressive modulus is possible. This study characterizes the mineralised hydrogels in terms of mineral formation and demonstrates the formation of CaP in dependence of ALP concentration and electron dose. Furthermore, investigations of uniaxial compression stability indicate increased compression moduli for mineralised electron beam-treated gelatin hydrogels. In summary, electron beam-treated mineralized gelatin hydrogels reveal good cytocompatibility for MG-63 osteoblast like cells indicating a high potential for BTE applications.

Carbon and Neon Ion Bombardment Induced Smoothing and Surface Relaxation of Titania Nanotubes.

Titania nanotube arrays with their enormous surface area are the subject of much attention in diverse fields of research. In the present work, we show that not only 60 keV and 150 keV ion bombardment of amorphous titania nanotube arrays yields defect creation within the tube walls, but it also changes the surface morphology: the surface relaxes and smoothens in accordance with a curvature-driven surface material's transport mechanism, which is mediated by radiation-induced viscous flow or radiation-enhanced surface diffusion, while the nanotubes act as additional sinks for the particle surface currents. These effects occur independently of the ion species: both carbon and neon ion bombardments result in comparable surface relaxation responses initiated by an ion energy of 60 keV at a fluence of 1 × 1016 ions/cm2. Using atomic force microscopy and contact angle measurements, we thoroughly study the relaxation effects on the surface topography and surface free energy, respectively. Moreover, surface relaxation is accompanied by further amorphization in surface-near regions and a reduction in the mass density, as demonstrated by Raman spectroscopy and X-ray reflectivity. Since ion bombardment can be performed on global and local scales, it constitutes a versatile tool to achieve well-defined and tunable topographies and distinct surface characteristics. Hence, different types of nanotube arrays can be modified for various applications.

Impact of high-energy electron irradiation on mechanical, structural and chemical properties of agarose hydrogels.

Due to their excellent biocompatibility and biodegradability, natural hydrogels are highly demanded biomaterials for biomedical applications such as wound dressing, tissue engineering, drug delivery or three dimensional cell culture. Highly energetic electron irradiation up to 10 MeV is a powerful and fast tool to sterilize and tailor the material's properties. In this study, electron radiation treatment of agarose hydrogels was investigated to evaluate radiation effects on physical, structural and chemical properties. The viscoelastic behavior, surface hydrophilicity and swelling behavior in a range of typical sterilization doses of 0 kGy to 30 kGy was analyzed. The mechanical properties were determined by rheology measurements and decreased by more than 20% compared to the initial moduli. The number average molecular weight between crosslinks was estimated based on rubber elasticity theory to judge on the radiation degradation. In this dose range, the number average molecular weight between crosslinks increased by more than 6%. Chemical structure was investigated by FTIR spectroscopy to evaluate the radiation resistance of agarose hydrogels. With increasing electron dose, an increasing amount of carbonyl containing species was observed. In addition, irradiation was accompanied by formation of gas cavities in the hydrogels. The gas products were specified for CO2, CO and H2O. Based on the radiolytic products, a radiolysis mechanism was proposed. Electron beam treatment under high pressure conditions was found to reduce gas cavity formation in the hydrogels.

A Versatile Macromer-Based Glycosaminoglycan (sHA3) Decorated Biomaterial for Pro-Osteogenic Scavenging of Wnt Antagonists.

High serum levels of Wnt antagonists are known to be involved in delayed bone defect healing. Pharmaceutically active implant materials that can modulate the micromilieu of bone defects with regard to Wnt antagonists are therefore considered promising to support defect regeneration. In this study, we show the versatility of a macromer based biomaterial platform to systematically optimize covalent surface decoration with high-sulfated glycosaminoglycans (sHA3) for efficient scavenging of Wnt antagonist sclerostin. Film surfaces representing scaffold implants were cross-copolymerized from three-armed biodegradable macromers and glycidylmethacrylate and covalently decorated with various polyetheramine linkers. The impact of linker properties (size, branching) and density on sHA3 functionalization efficiency and scavenging capacities for sclerostin was tested. The copolymerized 2D system allowed for finding an optimal, cytocompatible formulation for sHA3 functionalization. On these optimized sHA3 decorated films, we showed efficient scavenging of Wnt antagonists DKK1 and sclerostin, whereas Wnt agonist Wnt3a remained in the medium of differentiating SaOS-2 and hMSC. Consequently, qualitative and quantitative analysis of hydroxyapatite staining as a measure for osteogenic differentiation revealed superior mineralization on sHA3 materials. In conclusion, we showed how our versatile material platform enables us to efficiently scavenge and inactivate Wnt antagonists from the osteogenic micromilieu. We consider this a promising approach to reduce the negative effects of Wnt antagonists in regeneration of bone defects via sHA3 decorated macromer based macroporous implants.

Employing Nanostructured Scaffolds to Investigate the Mechanical Properties of Adult Mammalian Retinae Under Tension.

Numerous eye diseases are linked to biomechanical dysfunction of the retina. However, the underlying forces are almost impossible to quantify experimentally. Here, we show how biomechanical properties of adult neuronal tissues such as porcine retinae can be investigated under tension in a home-built tissue stretcher composed of nanostructured TiO2 scaffolds coupled to a self-designed force sensor. The employed TiO2 nanotube scaffolds allow for organotypic long-term preservation of adult tissues ex vivo and support strong tissue adhesion without the application of glues, a prerequisite for tissue investigations under tension. In combination with finite element calculations we found that the deformation behavior is highly dependent on the displacement rate which results in Young's moduli of (760-1270) Pa. Image analysis revealed that the elastic regime is characterized by a reversible shear deformation of retinal layers. For larger deformations, tissue destruction and sliding of retinal layers occurred with an equilibration between slip and stick at the interface of ruptured layers, resulting in a constant force during stretching. Since our study demonstrates how porcine eyes collected from slaughterhouses can be employed for ex vivo experiments, our study also offers new perspectives to investigate tissue biomechanics without excessive animal experiments.

Multifunctional coatings combining bioactive peptides and affinity-based cytokine delivery for enhanced integration of degradable vascular grafts.

Insufficient endothelialization of cardiovascular devices is a high-risk factor for implant failure. Presentation of extracellular matrix (ECM)-derived coatings is a well-known strategy to improve implant integration. However, the complexity of the system is challenging and strategies for applying multifunctionality are required. Here, we engineered mussel-derived surface-binding peptides equipped with integrin (c[RGDfK]) and proteoglycan binding sites (FHRRIKA) for enhanced endothelialization. Surface-binding properties of the platform containing l-3,4-dihydroxyphenylalanine (DOPA) residues were confirmed for hydrophilized polycaprolactone-co-lactide scaffolds as well as for glass and polystyrene. Further, heparin and the heparin-binding angiogenic factors VEGF, FGF-2 and CXCL12 were immobilized onto the peptide in a modular assembly. Presentation of bioactive peptides greatly enhanced human umbilical vein endothelial cell (HUVEC) adhesion and survival under static and fluidic conditions. In subsequent investigations, peptide-heparin-complexes loaded with CXCL12 or VEGF had an additional increasing effect on cell viability, differentiation and migration. Finally, hemocompatibility of the coatings was ensured. This study demonstrates that coatings combining adhesion peptides, glycosaminoglycans and modulators are a versatile tool to convey ECM-inspired multifunctionality to biomaterials and efficiently promote their integration.

Endothelialization of Titanium Surfaces by Bioinspired Cell Adhesion Peptide Coatings.

Common interventional therapies for cardiovascular occlusive diseases, such as the implantation of stents, are at risk of complications like thrombosis or restenosis. Drug-eluting stents have improved patency but simultaneously worsen the endothelialization of the implant. Here, we present a novel peptide coating derived from three proteins of the extracellular matrix named fibronectin, laminin, and elastin. Their active sequences RGD, SIKVAV, and VGVAPG were immobilized onto titanium surfaces by a carrier peptide containing l-3,4-dihydroxyphenylalanine (DOPA). Simultaneous functionalization of the carrier peptide with cyclic c[RGDfK] and SIKVAV had the most potent influence on adhesion, proliferation, viability, and angiogenesis of endothelial cells. By presentation of two adhesion peptides in one molecule, a synergistic enhancement of cell-surface interactions was achieved. Overall, this work clearly demonstrates the advantages of spatially defined peptide coatings for the endothelialization of titanium and thus describes a promising approach for the coating of stents.

Energetic electron assisted synthesis of highly tunable temperature-responsive collagen/elastin gels for cyclic actuation: macroscopic switching and molecular origins.

Thermoresponsive bio-only gels that yield sufficiently large strokes reversibly and without large hysteresis at a well-defined temperature in the physiological range, promise to be of value in biomedical application. Within the present work we demonstrate that electron beam modification of a blend of natural collagen and elastin gels is a route to achieve this goal, viz. to synthesize a bioresorbable gel with largely reversible volume contractions as large as 90% upon traversing a transition temperature that can be preadjusted between 36 °C and 43 °C by the applied electron dose. Employing circular dichroism and temperature depending confocal laser scanning microscopy measurements, we furthermore unravel the mechanisms underlying this macroscopic behavior on a molecular and network level, respectively and suggest a stringent picture to account for the experimental observations.

Magnetically responsive composites: electron beam assisted magnetic nanoparticle arrest in gelatin hydrogels for bioactuation.

As emerging responsive materials, ferrogels have become highly attractive for biomedical and technical applications in terms of soft actuation, tissue engineering or controlled drug release. In the present study, bioderived ferrogels were fabricated and successfully deformed within moderate, heterogeneous magnetic fields. Synthesis was realized by arresting iron oxide nanoparticles in porcine gelatin by introduction of covalent crosslinks via treatment with energetic electrons for mesh refinement. This approach also allows for tuning thermal and mechanical stability of the gelatin matrix. Operating the bioferrogel in compression, magnetic forces on the nanoparticles are counterbalanced by the stiffness of the hydrogel matrix that is governed by a shift in thermodynamic equilibrium of swelling, as derived in the framework of osmosis. As gelatin and iron oxide nanoparticles are established as biocompatible constituents, these findings promise potential for in vivo use as contactless mechanical transducers.

Regeneration of TiO2 Nanotube Arrays after Long-Term Cell and Tissue Culture for Multiple Use - an Environmental Scanning Electron Microscopy (ESEM) Survey of Adult Pig Retina and beyond.

Long-term organotypic culture of adult tissues not only open up possibilities for studying complex structures of explants in vitro, but also can be employed e.g. to investigate pathological changes, their fingerprints on tissue mechanics, as well as the effectiveness of drugs. While conventional culture methods do not allow for survival times of more than a few days, we have demonstrated recently that TiO2 nanotube arrays allow to maintain integrity of numerous tissues, including retina, brain, spline and tonsils, for as long as 2 weeks in vitro. A mystery in culturing has been the interaction of tissue with these substrates, which is also reflected by tissue debris after liftoff. As the latter reveals fingerprints of tissue adhesion and impedes with nanotube array reuse, we address within the present environmental scanning electron study debris nature and the effectiveness of cleaning approaches of distinct physical and chemical methods, including UV-light irradiation, O2 plasma treatment and application of an enzyme-based buffer. This will lays the foundation for large-scale regeneration and reuse of nanotube arrays in science and clinical research.

Contact Guidance by Microstructured Gelatin Hydrogels for Prospective Tissue Engineering Applications.

Design of functionalized biomimetic scaffolds is one of the key approaches for regenerative medicine and other biomedical applications. Development of engineered tissue should optimize organization and function of cells and tissue in vitro as well as in vivo. Surface topography is one factor controlling cellular behavior and tissue development. By topographical patterning of biocompatible materials, highly functionalized scaffolds can be developed. Gelatin is hereby a promising candidate due to its biocompatibility and biodegradability. It is low in cost and easy to handle, enabling a variety of applications in science and medicine. However, for biomedical applications at physiological conditions, gelatin has to be additionally stabilized since its gel-sol-transition temperature lies beneath the human body temperature. This is realized by a reagent-free cross-linking technique utilizing electron beam treatment. By topographical patterning, gelatin can be functionalized toward scaffolds for cell cultivation and tissue development. Thereby, customized patterns are transferred onto gelatin hydrogels via molds. Thermal stabilization of gelatin is then achieved by electron-induced cross-linking. In this study, we investigate the influence of gelatin concentration and irradiation dose on pattern transfer, long-term stability of topographically patterned gelatin hydrogels, and their impact on the cellular behavior of human umbilical vein endothelial cells as well as normal human dermal fibroblasts. We will show that contact guidance occurs for both cell types due to a concrete stripe pattern. In addition, the presented studies show a high degree of cytocompatibility, indicating a high potential of topographically patterned gelatin hydrogels as tissue development scaffold for prospective biomedical applications.