Evolution of flexible biting in hyperdiverse parasitoid wasps.

One key event in insect evolution was the development of mandibles with two joints, which allowed powerful biting but restricted their movement to a single degree of freedom. These mandibles define the Dicondylia, which constitute over 99% of all extant insect species. It was common doctrine that the dicondylic articulation of chewing mandibles remained unaltered for more than 400 million years. We report highly modified mandibles overcoming the restrictions of a single degree of freedom and hypothesize their major role in insect diversification. These mandibles are defining features of parasitoid chalcid wasps, one of the most species-rich lineages of insects. The shift from powerful chewing to precise cutting likely facilitated adaptations to parasitize hosts hidden in hard substrates, which pose challenges to the emerging wasps. We reveal a crucial step in insect evolution and highlight the importance of comprehensive studies even of putatively well-known systems.

Superporous Poly(ethylene glycol) Diacrylate Cryogel with a Defined Elastic Modulus for Prostate Cancer Cell Research.

The physical and mechanical properties of the tumor microenvironment are crucial for the growth, differentiation and migration of cancer cells. However, such microenvironment is not found in the geometric constraints of 2D cell culture systems used in many cancer studies. Prostate cancer research, in particular, suffers from the lack of suitable in vitro models. Here a 3D superporous scaffold is described with thick pore walls in a mechanically stable and robust architecture to support prostate tumor growth. This scaffold is generated from the cryogelation of poly(ethylene glycol) diacrylate to produce a defined elastic modulus for prostate tumor growth. Lymph node carcinoma of the prostate (LNCaP) cells show a linear growth over 21 d as multicellular tumor spheroids in such a scaffold with points of attachments to the walls of the scaffold. These LNCaP cells respond to the growth promoting effects of androgens and demonstrate a characteristic cytoplasmic-nuclear translocation of the androgen receptor and androgen-dependent gene expression. Compared to 2D cell culture, the expression or androgen response of prostate cancer specific genes is greatly enhanced in the LNCaP cells in this system. This scaffold is therefore a powerful tool for prostate cancer studies with unique advantages over 2D cell culture systems.

Direct three-dimensional imaging of polymer-water interfaces by nanoscale hard X-ray phase tomography.

We report three-dimensional (3D) direct imaging of complex surface-liquid interfaces by hard X-ray phase contrast tomography as a non-destructive approach for the morphological characterization of surfaces at the micro- and nanoscale in contact with water. Specifically, we apply this method to study the solid-air-water interface in hydrophobic macroporous polymethacrylate surfaces, and the solid-oil-water interface in slippery liquid-infused porous surfaces (SLIPS). Varying the isotropic spatial resolution allows the 3D quantitative characterization of individual polymer globules, globular clusters (porosity) as well as the infused lubricant layer on SLIPS. Surface defects were resolved at the globular level. We show the first application of X-ray nanotomography to hydrated surface characterizations and we anticipate that X-ray nanoscale imaging will open new ways for various surface/interface studies.

Introducing Biomedisa as an open-source online platform for biomedical image segmentation.

We present Biomedisa, a free and easy-to-use open-source online platform developed for semi-automatic segmentation of large volumetric images. The segmentation is based on a smart interpolation of sparsely pre-segmented slices taking into account the complete underlying image data. Biomedisa is particularly valuable when little a priori knowledge is available, e.g. for the dense annotation of the training data for a deep neural network. The platform is accessible through a web browser and requires no complex and tedious configuration of software and model parameters, thus addressing the needs of scientists without substantial computational expertise. We demonstrate that Biomedisa can drastically reduce both the time and human effort required to segment large images. It achieves a significant improvement over the conventional approach of densely pre-segmented slices with subsequent morphological interpolation as well as compared to segmentation tools that also consider the underlying image data. Biomedisa can be used for different 3D imaging modalities and various biomedical applications.

Quanfima: An open source Python package for automated fiber analysis of biomaterials.

Hybrid 3D scaffolds composed of different biomaterials with fibrous structure or enriched with different inclusions (i.e., nano- and microparticles) have already demonstrated their positive effect on cell integration and regeneration. The analysis of fibers in hybrid biomaterials, especially in a 3D space is often difficult due to their various diameters (from micro to nanoscale) and compositions. Though biomaterials processing workflows are implemented, there are no software tools for fiber analysis that can be easily integrated into such workflows. Due to the demand for reproducible science with Jupyter notebooks and the broad use of the Python programming language, we have developed the new Python package quanfima offering a complete analysis of hybrid biomaterials, that include the determination of fiber orientation, fiber and/or particle diameter and porosity. Here, we evaluate the provided tensor-based approach on a range of generated datasets under various noise conditions. Also, we show its application to the X-ray tomography datasets of polycaprolactone fibrous scaffolds pure and containing silicate-substituted hydroxyapatite microparticles, hydrogels enriched with bioglass contained strontium and alpha-tricalcium phosphate microparticles for bone tissue engineering and porous cryogel 3D scaffold for pancreatic cell culturing. The results obtained with the help of the developed package demonstrated high accuracy and performance of orientation, fibers and microparticles diameter and porosity analysis.

3D biodegradable scaffolds of polycaprolactone with silicate-containing hydroxyapatite microparticles for bone tissue engineering: high-resolution tomography and in vitro study.

To date, special interest has been paid to composite scaffolds based on polymers enriched with hydroxyapatite (HA). However, the role of HA containing different trace elements such as silicate in the structure of a polymer scaffold has not yet been fully explored. Here, we report the potential use of silicate-containing hydroxyapatite (SiHA) microparticles and microparticle aggregates in the predominant range from 2.23 to 12.40 µm in combination with polycaprolactone (PCL) as a hybrid scaffold with randomly oriented and well-aligned microfibers for regeneration of bone tissue. Chemical and mechanical properties of the developed 3D scaffolds were investigated with XRD, FTIR, EDX and tensile testing. Furthermore, the internal structure and surface morphology of the scaffolds were analyzed using synchrotron X-ray µCT and SEM. Upon culturing human mesenchymal stem cells (hMSC) on PCL-SiHA scaffolds, we found that both SiHA inclusion and microfiber orientation affected cell adhesion. The best hMSCs viability was revealed at 10 day for the PCL-SiHA scaffolds with well-aligned structure (~82%). It is expected that novel hybrid scaffolds of PCL will improve tissue ingrowth in vivo due to hydrophilic SiHA microparticles in combination with randomly oriented and well-aligned PCL microfibers, which mimic the structure of extracellular matrix of bone tissue.

Multifunctional Scaffolds with Improved Antimicrobial Properties and Osteogenicity Based on Piezoelectric Electrospun Fibers Decorated with Bioactive Composite Microcapsules.

The incorporation of bioactive compounds onto polymer fibrous scaffolds with further control of drug release kinetics is essential to improve the functionality of scaffolds for personalized drug therapy and regenerative medicine. In this study, polymer and hybrid microcapsules were prepared and used as drug carriers, which are further deposited onto polymer microfiber scaffolds [polycaprolactone (PCL), poly(3-hydroxybutyrate) (PHB), and PHB doping with the conductive polyaniline (PANi) of 2 wt % (PHB-PANi)]. The number of immobilized microcapsules decreased with increase in their ζ-potential due to electrostatic repulsion with the negatively charged fiber surface, depending on the polymer used for the scaffold's fabrication. Additionally, the immobilization of the capsules in dynamic mechanical conditions at a frequency of 10 Hz resulted in an increase in the number of the capsules on the fibers with increase in the scaffold piezoelectric response in the order PCL < PHB < PHB-PANi, depending on the chemical composition of the capsules. The immobilization of microcapsules loaded with different bioactive molecules onto the scaffold surface enabled multimodal triggering by physical (ultrasound, laser radiation) and biological (enzymatic treatment) stimuli, providing controllable release of the cargo from scaffolds. Importantly, the microcapsules immobilized onto the surface of the scaffolds did not influence the cell growth, viability, and cell proliferation on the scaffolds. Moreover, the attachment of human mesenchymal stem cells (hMSCs) on the scaffolds revealed that the PHB and PHB-PANi scaffolds promoted adhesion of hMSCs compared to that of the PCL scaffolds. Two bioactive compounds, antibiotic ceftriaxone sodium (CS) and osteogenic factor dexamethasone (DEXA), were chosen to load the microcapsules and demonstrate the antimicrobial properties and osteogenesis of the scaffolds. The modified scaffolds had prolonged release of CS or DEXA, which provided an improved antimicrobial effect, as well as enhanced osteogenic differentiation and mineralization of the scaffolds modified with capsules compared to that of individual scaffolds soaked in CS solution or incubated in an osteogenic medium. Thus, the immobilization of microcapsules provides a simple, convenient way to incorporate bioactive compounds onto polymer scaffolds, which makes these multimodal materials suitable for personalized drug therapy and bone tissue engineering.

High-resolution synchrotron X-ray analysis of bioglass-enriched hydrogels.

Enrichment of hydrogels with inorganic particles improves their suitability for bone regeneration by enhancing their mechanical properties, mineralizability, and bioactivity as well as adhesion, proliferation, and differentiation of bone-forming cells, while maintaining injectability. Low aggregation and homogeneous distribution maximize particle surface area, promoting mineralization, cell-particle interactions, and homogenous tissue regeneration. Hence, determination of the size and distribution of particles/particle agglomerates in the hydrogel is desirable. Commonly used techniques have drawbacks. High-resolution techniques (e.g., SEM) require drying. Distribution in the dry state is not representative of the wet state. Techniques in the wet state (histology, µCT) are of lower resolution. Here, self-gelling, injectable composites of Gellan Gum (GG) hydrogel and two different types of sol-gel-derived bioactive glass (bioglass) particles were analyzed in the wet state using Synchrotron X-ray radiation, enabling high-resolution determination of particle size and spatial distribution. The lower detection limit volume was 9 × 10(-5) mm(3) . Bioglass particle suspensions were also studied using zeta potential measurements and Coulter analysis. Aggregation of bioglass particles in the GG hydrogels occurred and aggregate distribution was inhomogeneous. Bioglass promoted attachment of rat mesenchymal stem cells (rMSC) and mineralization.

Hydrophobic liquid-infused porous polymer surfaces for antibacterial applications.

Biofilms represent a fundamental problem in environmental biology, water technology, food hygiene as well as in medical and technical systems. Recently introduced slippery liquid-infused porous surface (SLIPS) showed great promise for preventing biofilm formation owing to the low surface energy of such surface in combination with its self-cleaning properties. In this study we demonstrated a novel hydrophobic liquid-infused porous poly(butyl methacrylate-co-ethylene dimethacrylate) surface (slippery BMA-EDMA) with bacteria-resistance in BM2 mineral medium and long-term stability in aqueous environments. We showed that the slippery BMA-EDMA surface prevents biofilm formation of different strains of opportunistic pathogen Pseudomonas aeruginosa for at least up to 7 days in low nutrient medium. Only ∼1.8% of the slippery surface was covered by the environmental P. aeruginosa PA49 strain under investigation. In uncoated glass controls the coverage of surfaces reached ∼55% under the same conditions. However, in high nutrient medium, more relevant to physiological conditions, the biofilm formation on the slippery surface turned out to be highly dependent on the bacterial strain. Although the slippery surface could prevent biofilm formation of most of the P. aeruginosa strains tested (∼1% surface coverage), the multiresistant P. aeruginosa strain isolated from wastewater was able to cover up to 12% of the surface during 7 days of incubation. RAPD-PCR analysis of the used P. aeruginosa strains demonstrated their high genome variability, which might be responsible for their difference in biofilm formation on the slippery BMA-EDMA surface. The results show that although the slippery BMA-EDMA surface has a great potential against biofilm formation, the generality of its bacteria resistant properties is still to be improved.

Correlative nanoscale 3D imaging of structure and composition in extended objects.

Structure and composition at the nanoscale determine the behavior of biological systems and engineered materials. The drive to understand and control this behavior has placed strong demands on developing methods for high resolution imaging. In general, the improvement of three-dimensional (3D) resolution is accomplished by tightening constraints: reduced manageable specimen sizes, decreasing analyzable volumes, degrading contrasts, and increasing sample preparation efforts. Aiming to overcome these limitations, we present a non-destructive and multiple-contrast imaging technique, using principles of X-ray laminography, thus generalizing tomography towards laterally extended objects. We retain advantages that are usually restricted to 2D microscopic imaging, such as scanning of large areas and subsequent zooming-in towards a region of interest at the highest possible resolution. Our technique permits correlating the 3D structure and the elemental distribution yielding a high sensitivity to variations of the electron density via coherent imaging and to local trace element quantification through X-ray fluorescence. We demonstrate the method by imaging a lithographic nanostructure and an aluminum alloy. Analyzing a biological system, we visualize in lung tissue the subcellular response to toxic stress after exposure to nanotubes. We show that most of the nanotubes are trapped inside alveolar macrophages, while a small portion of the nanotubes has crossed the barrier to the cellular space of the alveolar wall. In general, our method is non-destructive and can be combined with different sample environmental or loading conditions. We therefore anticipate that correlative X-ray nano-laminography will enable a variety of in situ and in operando 3D studies.