Jürgen Groll

University of Wuerzburg | JMU · Department for Functional Materials in Medicine and Dentistry

Hydrogels are fascinating materials with high water content and low surface friction that can be tailored for numerous applications. However, their practical application is often hampered by an intrinsic mechanical weakness. Strategies for mechanically strong hydrogels have been developed, with double network (DN) hydrogels reaching remarkable comp...

Horseradish peroxidase (HRP) can be used for the enzymatic cross-linking of thiol-functionalized polymers under mild conditions to form hydrogels and nanogels without the need for added H(2) O(2) . Cells can be embedded in the hydrogels and proteins can be entrapped and released from the nanogels. These gels are fully degradable under mild and cyto...

Advanced biomaterials and scaffolds for tissue engineering place high demands on materials and exceed the passive biocompatibility requirements previously considered acceptable for biomedical implants. Together with degradability, the activation of specific cell–material interactions and a three-dimensional environment that mimics the extracellular...

Porous coordination polymers, in particular flexible porous coordination polymer networks that change their network structure on guest adsorption, have enormous potential in applications involving selective storage, separation and sensing. Despite the expected significant differences in their adsorption properties, porous coordination polymer nanoc...

Volumetric bioprinting (VBP) is a light‐based 3D printing platform which recently prompted a paradigm shift for additive manufacturing (AM) techniques considering its capability to enable the fabrication of complex cell‐laden geometries in tens of seconds with high spatiotemporal control and pattern accuracy. A flexible allyl‐modified gelatin (gelA...

3D bioprinting has developed tremendously in the last couple of years and enables the fabrication of simple, as well as complex, tissue models. The international space agencies have recognized the unique opportunities of these technologies for manufacturing cell and tissue models for basic research in space, in particular for investigating the effe...

Major challenges in biofabrication revolve around capturing the complex, hierarchical composition of native tissues. However, individual 3D printing techniques have limited capacity to produce composite biomaterials with multi-scale resolution. Volumetric bioprinting recently emerged as a paradigm-shift in biofabrication. This ultra-fast, light-bas...

Recreating the intricate mechanical and functional gradients found in natural tissues through additive manufacturing poses significant challenges, including the need for precise control over time and space and the availability of versatile biomaterial inks. In this proof-of-concept study, we developed a new biomaterial ink for direct ink writing, a...

This study aimed to develop a suitable hydrogel-based 3D platform to support long-term culture of primary endothelial cells (ECs) and fibroblasts. Two hydrogel systems based on allyl-modified gelatin (gelAGE), G1MM and G2LH, were cross-linked via thiol-ene click reaction with a four-arm thiolated polyethylene glycol (PEG-4-SH). Compared to G1MM, th...

As post‐COVID complications, chronic respiratory diseases are one of the foremost causes of mortality. The quest for a cure for this recent global challenge underlines that the lack of predictive in vitro lung models is one of the main bottlenecks in pulmonary preclinical drug development. Despite rigorous efforts to develop biomimetic in vitro lun...

Nanohydrogels combine advantages of hydrogels and nanoparticles. In particular, they represent promising drug delivery systems. Nanogel synthesis by oxidative condensation of polyglycidol prepolymers, that are modified with thiol groups, results in crosslinking by disulfide bonds. Hereby, biomolecules like the antidiabetic peptide RS1‐reg, derived...

Bioprinting In article number 2210521, Khoon S. Lim, and co‐workers highlight a scaffolding approach to engineering blood vessels, starting from lego like construction of macro‐scale vessels to functional micro‐scale vessels. Programmable sacrificial bioinks are developed, and applied to a range of biofabrication platforms, introducing architectura...

Major challenges in biofabrication revolve around capturing the complex, hierarchical composition of native tissues. However, individual 3D printing techniques have limited capacity to produce composite biomaterials with multi-scale resolution. Volumetric bioprinting recently emerged as a paradigm-shift in biofabrication. This ultra-fast, light-bas...

Sacrificial printing allows introduction of architectural cues within engineered tissue constructs. This strategy adopts the use of a 3D‐printed sacrificial ink that is embedded within a bulk hydrogel which is subsequently dissolved to leave open‐channels. However, current conventional sacrificial inks do not recapitulate the dynamic nature of tiss...

Biomimetic Membranes In article number 2205083, Ali Doryab, Otmar Schmid, and co‐workers describe how a biomimetic basement (BETA) membrane with a thickness of only 1 μm and excellent biocompatibility demonstrates the formation of the nanoscale fibrous network structure of extracellular matrix proteins (green) deposited by the cells (violet). These...

Lung fibrosis, as one of the major post‐COVID complications, is a progressive and ultimately fatal disease without a cure. Here, we introduce an organ‐ and disease‐specific in vitro mini‐lung fibrosis model equipped with non‐invasive real‐time monitoring of cell mechanics as a functional readout. To establish an intricate multi‐culture model under...

Hydrogel ink formulations based on rheology additives are becoming increasingly popular as they enable 3‐dimensional (3D) printing of non‐printable but biologically relevant materials. Despite the widespread use, a generalized understanding of how these hydrogel formulations become printable is still missing, mainly due to their variety and diversi...

The fluidity of Trypanosoma brucei ’s dense coat of GPI-anchored variant surface glycoproteins (VSGs) is fundamental for the survival of the parasite. In order to maintain the integrity of the coat, it is recycled on the time scale of a few minutes. This is surprisingly fast as endo- and exocytosis take place in the same small membrane invagination...

Current methods of microvessel fabrication mostly rely on self‐assembly in tiny volumes, prefabricated designs of microchannels, or demand complicated multi‐step procedures based on sacrificial templating to achieve specific geometrical features. Such application‐oriented geometries subsequently require a design‐specific and functional perfusion sy...

The regulatory solute carrier protein, family 1, member 1 (RS1) modulates via its N‐terminal domain RS1‐reg the activity of Na+–d‐glucose cotransporter 1 (SGLT1) and thereby the glucose uptake in the small intestine by blocking the release of SGLT1‐containing vesicles at the trans‐Golgi network (TGN). The antidiabetic activity of RS1 is mediated by...

In recent decades, hybrid characterization systems have become pillars in the study of cellular biomechanics. Especially, Atomic Force Microscopy (AFM) is combined with a variety of optical microscopy techniques to discover new aspects of cell adhesion. AFM, however, is limited to the early‐stage of cell adhesion, so that the forces of mature cell...

As central part of the innate immune response, immune cells fight against invaders through various mechanisms, such as the release of extracellular traps (ETs). While this mechanism is mainly known for neutrophils in biomaterial contact, the release of macrophage extracellular traps (METs) in response to biomaterials has not yet been reported. An i...

A novel dual setting brushite-gelatin cement was achieved by genip ininitiated cross-linking of gelatin during cement setting. Although the combination of an inorganic and organic phase resulted in a decrease of the compressive strength from about 10 MPa without polymeric phase to 3–6–MPa for gelatin modified composites, an increase in elastic prop...

The development of hydrogels suitable for biofabrication is essential to enable advanced approaches for tissue engineering and regenerative medicine. Applications in both hard and soft tissues require tailor-made bioinks to guide cellular behavior in a 3D matrix. In this study we aimed to enhance the stability and adjust the degradation behavior of...

Conventional additive-manufacturing technologies rely on the vertical stacking of layers, whereas each layer provides the structural integrity for the upcoming one. This inherently gives rise to limitations in freedom of design especially when structures containing large voids or truly 3D pathways for printed filaments are aspired. An especially in...

The fate and behavior of bone marrow mesenchymal stem/stromal cells (BM-MSC) is bidirectionally influenced by their microenvironment, the stem cell niche, where a magnitude of biochemical and physical cues communicate in an extremely orchestrated way. It is known that simplified 2D in vitro systems for BM-MSC culture do not represent their naïve ph...

The distribution and density of ligands have a determinant role in cell adhesion on planar substrates. At the same time, planar surfaces are nonphysiological for most cells, and cell behavior on planar and topographical surfaces is significantly different, with fibrous structures being the most natural environment for cells. Despite phenomenologica...

In 3D bioprinting for cartilage regeneration, bioinks that support chondrogenic development are of key importance. Growth factors covalently bound in non-printable hydrogels have been shown to effectively promote chondrogenesis. However, studies that investigate the functionality of tethered growth factors within 3D printable bioinks are still lack...

Mucin, a high molecular mass hydrophilic glycoprotein, is the main component of mucus that coats every wet epithelium in animals. It is thus intrinsically biocompatible, and with its protein backbone and the o-glycosidic bound oligosaccharides, it contains a plethora of functional groups which can be used for further chemical modifications. In this...

With the continuous growth of extrusion bioprinting techniques, ink formulations based on rheology modifiers are becoming increasingly popular, as they enable 3D printing of non-printable biologically-favored materials. However, benchmarking and characterization of such systems are inherently complicated due to the variety of rheology modifiers and...

Alginates are the most commonly used bioink in biofabrication, but their rheological profiles makes it very challenging to perform real 3D printing. In this study, an advanced hybrid hydrogel ink was developed, a mixture of thermogelling diblock copolymer, alginate and clay i.e. Laponite XLG. The reversible thermogelling and shear thinning properti...

3D bioprinting often involves application of highly concentrated polymeric bioinks to enable fabrication of stable cell-hydrogel constructs, although poor cell survival, compromised stem cell differentiation, and an inhomogeneous distribution of newly produced extracellular matrix (ECM) is frequently observed. Therefore, this study presents a bioin...

Hyaluronic acid (HA)-based hydrogels are very commonly applied as cell carriers for different approaches in regenerative medicine. HA itself is a well-studied biomolecule that originates from the physiological extracellular matrix (ECM) of mammalians and, due to its acidic polysaccharide structure, offers many different possibilities for suitable c...

Melt electrowriting (MEW) is an aspiring 3D printing technology with an unprecedented resolution among fiber-based printing technologies. It offers the ability to direct-write predefined designs utilizing a jet of molten polymer to fabricate constructs composed of fibers with diameters of only a few micrometers. These dimensions enable unique const...

Post-fabrication formation of a proper vasculature remains an unresolved challenge in bioprinting. Established strategies focus on the supply of the fabricated structure with nutrients and oxygen and either rely on the mere formation of a channel system using fugitive inks or additionally use mature endothelial cells and/or peri-endothelial cells s...

Biofabrication exploits additive manufacturing techniques for creating 3D structures with a precise geometry that aim to mimic a physiological cellular environment and to develop the growth of native tissues. The most recent approaches of 3D biofabrication integrate multiple technologies into a single biofabrication platform combining different mat...

This study aimed to develop printable calcium magnesium phosphate pastes that harden by immersion in ammonium phosphate solution post-printing. Besides the main mineral compound, biocompatible ceramic, magnesium oxide and hydroxypropylmethylcellulose (HPMC) were the crucial components. Two pastes with different powder to liquid ratios of 1.35 g/mL...

The study aims to highlight the importance of the process parameter choice during directional solidification of polymer solutions, as they have a significant influence on the pore structure and orientation. Biopolymer solutions (alginate and chitosan) are directionally frozen while systematically varying parameters such as the external temperature...

Adrenocortical carcinoma (ACC) is a malignant tumor originating from the adrenal gland cortex with a heterogeneous but overall dismal prognosis in advanced stages. For more than 50 years, mitotane has remained a cornerstone for the treatment of ACC as adjuvant and palliative therapy. It has a very poor aqueous solubility of 0.1 mg/l and high partit...

Porous scaffolds are widely used in biomedical applications where pore size and morphology influence a range of biological processes, including mass transfer of solutes, cellular interactions and organization, immune responses, and tissue vascularization, as well as drug delivery from biomaterials. Ice templating, one of the most widely utilized te...

Supplement‐free induction of cellular differentiation and polarization solely through the topography of materials is an auspicious strategy but has so far significantly lagged behind the efficiency and intensity of media‐supplementation‐based protocols. Consistent with the idea that 3D structural motifs in the extracellular matrix possess immunomod...

The presence of FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) is one of the most frequent mutations in acute myeloid leukemia (AML) and is associated with an unfavorable prognosis. FLT3 inhibitors, such as midostaurin, are used clinically but fail to entirely eradicate FLT3-ITD + AML. This study introduces a new perspective and...

As one kind of “smart” material, thermogelling polymers find applications in biofabrication, drug delivery and regenerative medicine. In this work, we report a thermosensitive poly(2-oxazoline)/poly(2-oxazine) based diblock copolymer comprising thermosensitive/moderately hydrophobic poly(2-N-propyl-2-oxazine) (pPrOzi) and thermosensitive/moderately...

Fabrication of microchannels using 3D printing of sugars as fugitive material is explored in different fields, including microfluidics. However, establishing reproducible methods for the controlled production of sugar structures with sub-100 μm dimensions remains a challenge. This study pioneers the processing of sugars by melt electrowriting (MEW)...

Reinforced hydrogels represent a promising strategy for tissue engineering of articular cartilage. They can recreate mechanical and biological characteristics of native articular cartilage and promote cartilage regeneration in combination with mesenchymal stromal cells. One of the limitations of in vivo models for testing the outcome of tissue engi...

Endowing materials and scaffolds with immunomodulatory properties has evolved into a very active field of research. However, combining such effects with multifunctionality regarding cell adhesion and manipulation is still challenging due to the intricate nature of cell–substrate interactions that require fine-tuning of scaffold properties. Here, we...

Bioprinting has evolved into a thriving technology for the fabrication of cell-laden scaffolds. Bioinks are the most critical component for bioprinting. Recently, microgels have been introduced as a very promising bioink enabling cell protection and the control of the cellular microenvironment. However, their microfluidic fabrication inherently see...

Post-fabrication formation of a proper vasculature remains an unresolved challenge in bioprinting. Established strategies focus on the supply of the fabricated structure with nutrients and oxygen and either rely on the mere formation of a channel system using fugitive inks, or additionally use mature endothelial cells and/or peri-endothelial cells...

Interactions between proteins and carbohydrates with larger biomacromolecules, e.g., lectins, are usually examined using self-assembled monolayers on target gold surfaces as a simplified model measuring setup. However, most of those measuring setups are either limited to a single substrate or do not allow for control over ligand distance and spacin...

Aligned porous non‐sintered and sintered a‐tricalcium phosphate (a‐TCP) scaffolds are prepared by ice‐templating and converted into the low‐temperature calcium phosphates calcium‐deficient hydroxyapatite (CDHA), brushite and monetite. This is achieved by hydrothermal treatment or incubation in phosphoric acid solution and has a high clinical potent...

As one kind of smart material, thermogelling polymers find applications in biofabrication, drug delivery and regenerative medicine. Here, we reported on a novel thermosensitive hydrogel which can be 3D printed using extrusion based printing. Gel strength was found around 3kPa storage modulus with pronounced shear thinning and rapid recovery after s...

In this study, an advanced hybrid ink was developed, based on a thermogelling block copolymer, alginate and clay. The reversible thermogelling and shear thinning properties polymer acts at the same time as a fugitive material on the macromolecular level and facilitates the cell-laden extrusion based bioprinting. <br

Biofabrication, including printing technologies, has emerged as a powerful approach to the design of disease models, such as in cancer research. In breast cancer, adipose tissue has been acknowledged as an important part of the tumor microenvironment favoring tumor progression. Therefore, in this study, a 3D-printed breast cancer model for facilita...

Aspergillus fumigatus is the opportunistic fungus responsible for a variety of serious and often lethal diseases of immunocompromised patients, such as invasive aspergillosis, aspergilloma, and allergic bronchopulmonary aspergillosis. Therapeutic options for such fungal infections are limited due to the high toxicity of currently available drugs. H...

The mechanisms underlying the cellular response to extracellular matrices (ECMs) that consist of multiple adhesive ligands are still poorly understood. Here, we address this topic by monitoring specific cellular responses to two different extracellular adhesion molecules – the main integrin ligand fibronectin and galectin-8, a lectin that binds β-g...

Enhancing the colloidal stability of silver nanoparticles (AgNPs) is crucial to maintain their unique properties allowing broad application of these NPs. Stabilization of AgNPs is usually achieved by surface modification with thiol containing polymers showing limitations owing to the nucleophilic and oxidative character, whereas chemical inert thio...

Biointerface engineering is a wide‐spread strategy to improve the healing process and subsequent tissue integration of biomaterials. Especially the integration of specific peptides is one promising strategy to promote the regenerative capacity of implants and 3D scaffolds. In vivo, these tailored interfaces are, however, first confronted with the i...

A hydrogel system based on oxidized alginate covalently crosslinked with gelatin (ADA-GEL) has been utilized for different biofabrication approaches to design constructs, in which cell growth, proliferation and migration have been observed. However, cell–bioink interactions are not completely understood and the potential effects of free aldehyde gr...

Fabricating a porous scaffold with high surface area has been a major strategy in the tissue engineering field. Among the many fabrication methods, electrospinning has become one of the cornerstone techniques due to its enabling the fabrication of highly porous fibrous scaffolds that are of natural or synthetic origin. Apart from the basic requirem...

div>Supplement-free induction of cellular differentiation and polarization solely through the topography of materials is an auspicious strategy but has so far significantly lacked behind the efficiency and intensity of media-supplementation based protocols. For immune cells, low intensity effects were achieved on rhodent cells using standard techno...

Bulk hydrogels traditionally used for tissue engineering and drug delivery have numerous limitations, such as restricted injectability and a nanoscale porosity that reduces cell invasion and mass transport. An evolving approach to address these limitations is the fabrication of hydrogel microparticles (i.e., "microgels") that can be assembled into...