This study presents an X-ray computed nanotomography (nano-CT) based, high-resolution imaging technique. Thanks to a voxel resolution of 540 nm, this novel technique is suitable for observing the 3D morphology of soft biopolymeric scaffolds seeded with stem cells. A sample of highly porous collagen scaffold seeded with contrasted mesenchymal stem cells (MSC) was investigated by using lab-based nano-CT. The whole volume of the sample was analysed without its destruction. To evaluate the potential of nano-CT, a comparison measurement was done using a standard microscopy technique. Scanning electron microscopy (SEM) combined with energy dispersive X-ray analysis (EDX) established an extension and local accumulation of the contrasting agent - heavy metallic osmium tetroxide. The presented imaging technique is novel as it will help to understand better the behaviour of cells while interacting with three-dimensional biomaterials. This is crucial for both experimental and clinical tissue engineering applications in order to limit the risk of uncontrolled cell growth, and potentially tumour formation. LAY DESCRIPTION: Biomaterials play a crucial role in tissue engineering by serving as 3D scaffolds for cellular attachment, proliferation, and in growth ultimately leading to new tissue formation. Cell morphology and proliferation inside the 3D scaffold are necessary to know for assessing cell viability. However, these studies are usually negatively affected by the limitations of imaging techniques. We demonstrate that X-ray computed nanotomography (nano-CT), based on high-resolution imaging technique providing voxel resolution of 540 nm, is a suitable method for observing the 3D morphology of soft biopolymeric scaffolds seeded with stem cells. A sample of highly porous collagen scaffold seeded with contrasted mesenchymal stem cells (MSC) was investigated by using a lab-based nano-CT. The whole volume of the sample was analysed without its destruction. To evaluate the potential of nano-CT, a comparison measurement was done using a standard microscopy technique. Scanning electron microscopy in a combination with energy dispersive X-ray analysis established an extension and local accumulation of the contrasting agent - heavy metallic osmium tetroxide. The presented imaging technique is novel as it will help to understand better the behaviour of cells while interacting with three-dimensional biomaterials. This is crucial for both experimental and clinical tissue engineering applications in order to limit the risk of uncontrolled cell growth, and potentially tumour formation.

• Klíčová slova
• Biopolymeric scaffold, SEM/EDX, X-ray computed nanotomography, mesenchymal stem cells, tissue engineering,
• MeSH
• biokompatibilní materiály MeSH
• buněčné kultury MeSH
• kolagen chemie   MeSH
• králíci MeSH
• kultivované buňky MeSH
• mezenchymální kmenové buňky ultrastruktura   MeSH
• mikroskopie elektronová rastrovací metody   MeSH
• poréznost MeSH
• rentgenová mikrotomografie metody   MeSH
• tkáňové podpůrné struktury * MeSH
• viabilita buněk MeSH
• zobrazování trojrozměrné metody   MeSH
• zvířata MeSH
• Check Tag
• králíci MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• biokompatibilní materiály MeSH
• kolagen MeSH

Cypridoidean ostracods are one of a number of animal taxa that reproduce with giant sperm, up to 10 000 µm in length, but they are the only group to have aflagellate, filamentous giant sperm. The evolution and function of this highly unusual feature of reproduction with giant sperm are currently unknown. The hypothesis of long-term evolutionary persistence of this kind of reproduction has never been tested. We here report giant sperm discovered by propagation phase contrast X-ray synchrotron micro- and nanotomography, preserved in five Miocene ostracod specimens from Queensland, Australia. The specimens belong to the species Heterocypris collaris Matzke-Karasz et al. 2013 (one male and three females) and Newnhamia mckenziana Matzke-Karasz et al. 2013 (one female). The sperm are not only the oldest petrified gametes on record, but include three-dimensional subcellular preservation. We provide direct evidence that giant sperm have been a feature of this taxon for at least 16 Myr and provide an additional criterion (i.e. longevity) to test hypotheses relating to origin and function of giant sperm in the animal kingdom. We further argue that the highly resistant, most probably chitinous coats of giant ostracod sperm may play a role in delaying decay processes, favouring early mineralization of soft tissue.

• Klíčová slova
• Cypridoidea, bat guano, fossil gametes, soft body preservation, synchrotron radiation tomography,
• MeSH
• biologická evoluce MeSH
• jeskyně * MeSH
• korýši ultrastruktura   MeSH
• mikroskopie elektronová rastrovací MeSH
• rentgenová mikrotomografie MeSH
• spermie ultrastruktura   MeSH
• transmisní elektronová mikroskopie MeSH
• zkameněliny * MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Austrálie MeSH
• Queensland MeSH

In this study, the potential of highly porous hydrogels based on biodegradable synthetic poly(α-amino acids) to support proliferation and chondrogenesis of human dental pulp stem cells (hDPSCs) was investigated. Covalently crosslinked gels with permanent pores were formed under cryogenic conditions by free-radical copolymerization of poly[N5-(2-hydroxyethyl)-l-glutamine-stat-N5-(2-methacryloyl-oxy-ethyl)-l-glutamine] (PHEG-MA) with 2-hydroxyethyl methacrylate (HEMA) and N-propargyl methacrylamide (PrMAAm) as minor co-monomers. PrMAAm provided alkyne groups for modifying the gels with cell-supporting moieties (RGDS peptides) by the azide-alkyne "click"-reaction. Two types of gels with different compressive moduli were prepared. Each type was modified with two different concentrations of RGDS peptide. X-ray computed nanotomography (nanoCT) was used to visualize and analyze the 3D-structure of the cryogels. It was shown that modifying the PHEG-MA cryogels within the range of RGDS concentrations examined here had a positive effect on the proliferation of hDPSCs. Immunofluorescence staining for collagen type 2 and aggrecan proved that there was differentiation of hDPSCs into chondrocytes.

• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH