The extracellular matrix (ECM) plays a crucial role in organoid cultures by supporting cell proliferation and differentiation. A key feature of the ECM is its mechanical influence on the surrounding cells, directly affecting their behavior. Matrigel, the most commonly used ECM, is limited by its animal-derived origin, batch variability, and uncontrollable mechanical properties, restricting its use in 3D cell-model-based mechanobiological studies. Poly(2-alkyl-2-oxazoline) (PAOx) synthetic hydrogels represent an appealing alternative because of their reproducibility and versatile chemistry, enabling tuning of hydrogel stiffness and functionalization. Here, we studied PAOx hydrogels with differing compressive moduli for their potential to support 3D cell growth. PAOx hydrogels support spheroid and organoid growth over several days without the addition of ECM components. Furthermore, we discovered intestinal organoid epithelial polarity reversion in PAOx hydrogels and demonstrate how the tunable mechanical properties of PAOx can be used to study effects on the morphology and oxygenation of live multicellular spheroids.

• Publikační typ
• časopisecké články MeSH

The effectiveness of cell transplantation can be improved by optimization of the transplantation site. For some types of cells that form highly oxygen-demanding tissue, e.g., pancreatic islets, a successful engraftment depends on immediate and sufficient blood supply. This critical point can be avoided when cells are transplanted into a bioengineered pre-vascularized cavity which can be formed using a polymer scaffold. In our study, we tested surface-modified poly(lactide-co-caprolactone) (PLCL) capsular scaffolds containing the pro-angiogenic factor VEGF. After each modification step (i.e., amination and heparinization), the surface properties and morphology of scaffolds were characterized by ATR-FTIR and XPS spectroscopy, and by SEM and AFM. All modifications preserved the gross capsule morphology and maintained the open pore structure. Optimized aminolysis conditions decreased the Mw of PLCL only up to 10% while generating a sufficient number of NH2 groups required for the covalent immobilization of heparin. The heparin layer served as a VEGF reservoir with an in vitro VEGF release for at least four weeks. In vivo studies revealed that to obtain highly vascularized PLCL capsules (a) the optimal VEGF dose for the capsule was 50 μg and (b) the implantation time was four weeks when implanted into the greater omentum of Lewis rats; dense fibrous tissue accompanied by vessels completely infiltrated the scaffold and created sparse granulation tissue within the internal cavity of the capsule. The prepared pre-vascularized pouch enabled the islet graft survival and functioning for at least 50 days after islet transplantation. The proposed construct can be used to create a reliable pre-vascularized pouch for cell transplantation.

• MeSH
• bioinženýrství * MeSH
• experimentální diabetes mellitus chemicky indukované   metabolismus   patologie   MeSH
• fyziologická neovaskularizace * MeSH
• injekce intraperitoneální MeSH
• krevní glukóza analýza   MeSH
• krysa rodu Rattus MeSH
• molekulární struktura MeSH
• polyestery chemie   metabolismus   MeSH
• potkani inbrední LEW MeSH
• streptozocin aplikace a dávkování   MeSH
• tobolky chemie   metabolismus   MeSH
• transplantace Langerhansových ostrůvků * MeSH
• vaskulární endoteliální růstové faktory chemie   metabolismus   MeSH
• velikost částic MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• krevní glukóza MeSH
• poly(lactide) MeSH Prohlížeč
• polyestery MeSH
• streptozocin MeSH
• tobolky MeSH
• vaskulární endoteliální růstové faktory MeSH

Correction for 'Bioengineering a pre-vascularized pouch for subsequent islet transplantation using VEGF-loaded polylactide capsules' by Naresh Kasoju et al., Biomater. Sci., 2020, DOI: 10.1039/c9bm01280j.

• Publikační typ
• časopisecké články MeSH
• tisková chyba MeSH

Thermally induced phase separation (TIPS) based methods are widely used for the fabrication of porous scaffolds for tissue engineering and related applications. However, formation of a less-/non-porous layer at the scaffold's outer surface at the air-liquid interface, often known as the skin-effect, restricts the cell infiltration inside the scaffold and therefore limits its efficacy. To this end, we demonstrate a TIPS-based process involving the exposure of the just quenched poly(lactide-co-caprolactone):dioxane phases to the pure dioxane for a short time while still being under the quenching strength, herein after termed as the second quenching (2Q). Scanning electron microscopy, mercury intrusion porosimetry and contact angle analysis revealed a direct correlation between the time of 2Q and the gradual disappearance of the skin, followed by the widening of the outer pores and the formation of the fibrous filaments over the surface, with no effect on the internal pore architecture and the overall porosity of scaffolds. The experiments at various quenching temperatures and polymer concentrations revealed the versatility of 2Q in removing the skin. In addition, the in vitro cell culture studies with the human primary fibroblasts showed that the scaffolds prepared by the TIPS based 2Q process, with the optimal exposure time, resulted in a higher cell seeding and viability in contrast to the scaffolds prepared by the regular TIPS. Thus, TIPS including the 2Q step is a facile, versatile and innovative approach to fabricate the polymer scaffolds with a skin-free and fully open porous surface morphology for achieving a better cell response in tissue engineering and related applications.

• MeSH
• analýza selhání vybavení MeSH
• biokompatibilní materiály chemická syntéza   MeSH
• chemická frakcionace metody   MeSH
• design vybavení MeSH
• polyestery chemie   MeSH
• polymery chemie   MeSH
• poréznost MeSH
• povrchové vlastnosti MeSH
• testování materiálů MeSH
• tkáňové inženýrství přístrojové vybavení   metody   MeSH
• tkáňové podpůrné struktury * MeSH
• vytápění metody   MeSH
• změna skupenství MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• biokompatibilní materiály MeSH
• lactide-caprolactone copolymer MeSH Prohlížeč
• polyestery MeSH
• polymery MeSH

We present an investigation of the preparation of highly porous hydrogels based on biodegradable synthetic poly(α-amino acid) as potential tissue engineering scaffolds. Covalently cross-linked gels with permanent pores were formed under cryogenic conditions by free-radical copolymerization of poly[N(5)-(2-hydroxyethyl)-L-glutamine-stat-N(5)-(2-methacryloyl-oxy-ethyl)-L-glutamine] (PHEG-MA) with 2-hydrohyethyl methacrylate (HEMA) and, optionally, N-propargyl acrylamide (PrAAm) as minor comonomers. The morphology of the cryogels showed interconnected polyhedral or laminar pores. The volume content of communicating water-filled pores was >90%. The storage moduli of the swollen cryogels were in the range of 1-6 kPa, even when the water content was >95%. The enzymatic degradation of a cryogel corresponded to the decrease in its storage modulus during incubation with papain, a model enzyme with specificity analogous to wound-healing enzymes. It was shown that cryogels with incorporated alkyne groups can easily be modified with short synthetic peptides using azide-alkyne cycloaddition "click" chemistry, thus providing porous hydrogel scaffolds with biomimetic features.

• MeSH
• akrylamidy chemie   MeSH
• aminokyseliny chemie   MeSH
• biokompatibilní materiály chemie   MeSH
• biomimetika MeSH
• kryogely chemie   MeSH
• methakryláty chemie   MeSH
• morfinany chemie   MeSH
• peptidy chemie   MeSH
• polymerizace MeSH
• polymery chemie   MeSH
• poréznost MeSH
• syntetická chemie okamžité shody * MeSH
• tkáňové inženýrství MeSH
• tkáňové podpůrné struktury chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• akrylamidy MeSH
• aminokyseliny MeSH
• biokompatibilní materiály MeSH
• kryogely MeSH
• methakryláty MeSH
• morfinany MeSH
• N-propargyl MeSH Prohlížeč
• peptidy MeSH
• polymery MeSH

The ability to tailor mechanical properties and architecture is crucial in creating macroporous hydrogel scaffolds for tissue engineering. In the present work, a technique for the modification of the pore size and stiffness of acrylamide-based cryogels is demonstrated via the regulation of an electron beam irradiation dose. The samples were characterized by equilibrium swelling measurements, light and scanning electron microscopy, mercury porosimetry, Brunauer-Emmett-Teller surface area analysis, and stiffness measurements. Their properties were compared to cryogels prepared by a standard redox-initiated radical polymerization. A (125)I radiolabeled azidopentanoyl-GGGRGDSGGGY-NH2 peptide was bound to the surface to determine the concentration of the adhesive sites available for biomimetic modification. The functionality of the prepared substrates was evaluated by in vitro cultivation of adipose-derived stem cells. Moreover, the feasibility of preparing layered cryogels was demonstrated. This may be the key to the future preparation of complex hydrogel-based scaffolds to mimic the extracellular microenvironment in a wide range of applications.

• MeSH
• elektrony MeSH
• kryogely chemická syntéza   farmakologie   MeSH
• lidé MeSH
• polymerizace * MeSH
• poréznost * MeSH
• tukové buňky účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kryogely MeSH

The additive manufacturing technique of direct laser writing by two-photon polymerization (2PP-DLW) enables the fabrication of three-dimensional microstructures with superior accuracy and flexibility. When combined with biomimetic hydrogel materials, 2PP-DLW can be used to recreate the microarchitectures of the extracellular matrix. However, there are currently only a limited number of hydrogels applicable for 2PP-DLW. In order to widen the selection of synthetic biodegradable hydrogels, in this work we studied the 2PP-DLW of methacryloylated and acryloylated poly(α-amino acid)s (poly(AA)s). The performance of these materials was compared to widely used poly(ethylene glycol) diacrylates (PEGdas) in terms of polymerization and damage thresholds, voxel size, line width, post-polymerization swelling and deformation. We found that both methacryloylated and acryloylated poly(AA) hydrogels are suitable to 2PP-DLW with a wider processing window than PEGdas. The poly(AA) with the highest degree of acryloylation showed the greatest potential for 3D microfabrication.

• Klíčová slova
• Direct laser writing, Hydrogel, Microfabrication, Poly(ethylene glycol) diacrylate, Polyamino acid, Two-photon polymerization,
• MeSH
• aminokyseliny chemie   MeSH
• fotony MeSH
• hydrogely * MeSH
• lasery MeSH
• mikroskopie elektronová rastrovací MeSH
• polyethylenglykoly chemie   MeSH
• polymerizace * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• aminokyseliny MeSH
• hydrogely * MeSH
• poly(ethylene glycol)diacrylate MeSH Prohlížeč
• polyethylenglykoly MeSH

Biodegradable hydrogels are studied as potential scaffolds for soft tissue regeneration. In this work biodegradable hydrogels were prepared from synthetic poly(α-amino acid)s, poly(AA)s. The covalently crosslinked gels were formed by radical copolymerization of methacryloylated poly(AA)s, e.g. poly[N (5)-(2-hydroxy-ethyl)-L-glutamine-ran-L-alanine-ran-N (6)-methacryloyl-L-lysine], as a multifunctional macro-monomer with a low-molecular-weight methacrylic monofunctional monomer, e.g. 2-hydroxyethyl methacrylate (HEMA). Methacryloylated copolypeptides were synthesized by polymerization of N-carboxyanhydrides of respective amino acids and subsequent side-chain modification. Due to their polypeptide backbone, synthetic poly(AA)s are cleavable in biological environment by enzyme-catalyzed hydrolysis. The feasibility of enzymatic degradation of poly(AA)s alone and the hydrogels made from them was studied using elastase, a matrix proteinase involved in tissue healing processes, as a model enzyme. Specificity of elastase for cleavage of polypeptide chains behind the L-alanine residues was reflected in faster degradation of L-alanine-containing copolymers as well as of hydrogels composed of them.

• MeSH
• aminokyseliny chemie   MeSH
• biodegradace MeSH
• biokompatibilní materiály chemie   MeSH
• časové faktory MeSH
• chemické modely MeSH
• chrupavka patologie   MeSH
• gely MeSH
• hydrogely chemie   MeSH
• magnetická rezonanční spektroskopie MeSH
• methakryláty chemie   MeSH
• pankreatická elastasa chemie   MeSH
• peptidy chemie   MeSH
• polymery chemie   MeSH
• reagencia zkříženě vázaná chemie   MeSH
• regenerace nervu MeSH
• tkáňové inženýrství přístrojové vybavení   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• aminokyseliny MeSH
• biokompatibilní materiály MeSH
• gely MeSH
• hydrogely MeSH
• hydroxyethyl methacrylate MeSH Prohlížeč
• methakryláty MeSH
• pankreatická elastasa MeSH
• peptidy MeSH
• polymery MeSH
• reagencia zkříženě vázaná MeSH