An RNA-dependent and phase-separated active subnuclear compartment safeguards repressive chromatin domains

The nucleus is composed of functionally distinct membraneless compartments that undergo phase separation (PS). However, whether different subnuclear compartments are connected remains elusive. We identified a type of nuclear body with PS features composed of BAZ2A that associates with active chromatin. BAZ2A bodies depend on RNA transcription and BAZ2A non-disordered RNA-binding TAM domain. Although BAZ2A and H3K27me3 occupancies anticorrelate in the linear genome, in the nuclear space, BAZ2A bodies contact H3K27me3 bodies. BAZ2A-body disruption promotes BAZ2A invasion into H3K27me3 domains, causing H3K27me3-body loss and gene upregulation. Weak BAZ2A-RNA interactions, such as with nascent transcripts, promote BAZ2A bodies, whereas the strong binder long non-coding RNA (lncRNA) Malat1 impairs them while mediating BAZ2A association to chromatin at nuclear speckles. In addition to unraveling a direct connection between nuclear active and repressive compartments through PS mechanisms, the results also showed that the strength of RNA-protein interactions regulates this process, contributing to nuclear organization and the regulation of chromatin and gene expression.

Synergy between 3D-extruded electroconductive scaffolds and electrical stimulation to improve bone tissue engineering strategies

In this work, we propose a simple, reliable, and versatile strategy to create 3D electroconductive scaffolds suitable for bone tissue engineering (TE) applications with electrical stimulation (ES). The proposed scaffolds are made of 3D-extruded poly(ε-caprolactone) (PCL), subjected to alkaline treatment, and of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), anchored to PCL with one of two different crosslinkers: (3-glycidyloxypropyl)trimethoxysilane (GOPS) and divinyl sulfone (DVS). Both cross-linkers allowed the formation of a homogenous and continuous coating of PEDOT:PSS to PCL. We show that these PEDOT:PSS coatings are electroconductive (11.3-20.1 S cm-1), stable (up to 21 days in saline solution), and allow the immobilization of gelatin (Gel) to further improve bioactivity. In vitro mineralization of the corresponding 3D conductive scaffolds was greatly enhanced (GOPS(NaOH)-Gel - 3.1 fold, DVS(NaOH)-Gel - 2.0 fold) and cell colonization and proliferation were the highest for the DVS(NaOH)-Gel scaffold. In silico modelling of ES application in DVS(NaOH)-Gel scaffolds indicates that the electrical field distribution is homogeneous, which reduces the probability of formation of faradaic products. Osteogenic differentiation of human bone marrow derived mesenchymal stem/stromal cells (hBM-MSCs) was performed under ES. Importantly, our results clearly demonstrated a synergistic effect of scaffold electroconductivity and ES on the enhancement of MSC osteogenic differentiation, particularly on cell-secreted calcium deposition and the upregulation of osteogenic gene markers such as COL I, OC and CACNA1C. These scaffolds hold promise for future clinical applications, including manufacturing of personalized bone TE grafts for transplantation with enhanced maturation/functionality or bioelectronic devices.

Design of Experiment for Optimizing Microencapsulation by the Solvent Evaporation Technique

We employed microemulsion combined with the solvent evaporation technique to produce biodegradable polycaprolactone (PCL) MCs, containing encapsulated isophorone diisocyanate (IPDI), to act as crosslinkers in high-performance adhesive formulations. The MC production process was optimized by applying a design of experiment (DoE) statistical approach, aimed at decreasing the MCs' average size. For that, three different factors were considered, namely the concentration of two emulsifiers, polyvinyl alcohol (PVA) and gum arabic (GA); and the oil-to-water phase ratio of the emulsion. The significance of each factor was evaluated, and a predictive model was developed. We were able to decrease the average MC size from 326 μm to 70 µm, maintaining a high encapsulation yield of approximately 60% of the MCs' weight, and a very satisfactory shelf life. The MCs' average size optimization enabled us to obtain an improved distributive and dispersive mixture of isocyanate-loaded MCs at the adhesive bond. The MCs' suitability as crosslinkers for footwear adhesives was assessed following industry standards. Peel tests revealed peel strength values above the minimum required for casual footwear, while the creep test results indicated an effective crosslinking of the adhesive. These results confirm the ability of the MCs to release IPDI during the adhesion process and act as crosslinkers for new adhesive formulations.

Mechanistic Study of the Formation of Multicomponent Oxide Porous Microspheres (MICROSCAFS®) by Cryo-Scanning Electron Microscopy

Multicomponent oxide microspheres with interconnected macroporosity (MICROSCAFS®) are new materials with great potential as support materials for photocatalysis, optimized for real life applications and for other uses that are still being explored. They are obtained from an adapted sol-gel process combined with phase separation phenomena that occur within the water droplets of an emulsion. We present here a methodology based on cryogenic scanning electron microscopy (cryo-SEM) that allows, with minimal specimen preparation, the direct and in situ visualization of 'wet' alkoxide-derived microstructures, for the mechanistic study of the complex process of MICROSCAFS® generation. It is simultaneously combined with energy dispersive X-ray spectroscopy (EDS) to visualize phase separation phenomena and study the chemical elemental composition at specific regions of the sample and reaction times.

Novel Electroactive Mineralized Polyacrylonitrile/PEDOT:PSS Electrospun Nanofibers for Bone Repair Applications

Bone defect repair remains a critical challenge in current orthopedic clinical practice, as the available therapeutic strategies only offer suboptimal outcomes. Therefore, bone tissue engineering (BTE) approaches, involving the development of biomimetic implantable scaffolds combined with osteoprogenitor cells and native-like physical stimuli, are gaining widespread interest. Electrical stimulation (ES)-based therapies have been found to actively promote bone growth and osteogenesis in both in vivo and in vitro settings. Thus, the combination of electroactive scaffolds comprising conductive biomaterials and ES holds significant promise in improving the effectiveness of BTE for clinical applications. The aim of this study was to develop electroconductive polyacrylonitrile/poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PAN/PEDOT:PSS) nanofibers via electrospinning, which are capable of emulating the native tissue's fibrous extracellular matrix (ECM) and providing a platform for the delivery of exogenous ES. The resulting nanofibers were successfully functionalized with apatite-like structures to mimic the inorganic phase of the bone ECM. The conductive electrospun scaffolds presented nanoscale fiber diameters akin to those of collagen fibrils and displayed bone-like conductivity. PEDOT:PSS incorporation was shown to significantly promote scaffold mineralization in vitro. The mineralized electroconductive nanofibers demonstrated improved biological performance as observed by the significantly enhanced proliferation of both human osteoblast-like MG-63 cells and human bone marrow-derived mesenchymal stem/stromal cells (hBM-MSCs). Moreover, mineralized PAN/PEDOT:PSS nanofibers up-regulated bone marker genes expression levels of hBM-MSCs undergoing osteogenic differentiation, highlighting their potential as electroactive biomimetic BTE scaffolds for innovative bone defect repair strategies.

Hydroxyapatite-filled osteoinductive and piezoelectric nanofibers for bone tissue engineering

Osteoporotic-related fractures are among the leading causes of chronic disease morbidity in Europe and in the US. While a significant percentage of fractures can be repaired naturally, in delayed-union and non-union fractures surgical intervention is necessary for proper bone regeneration. Given the current lack of optimized clinical techniques to adequately address this issue, bone tissue engineering (BTE) strategies focusing on the development of scaffolds for temporarily replacing damaged bone and supporting its regeneration process have been gaining interest. The piezoelectric properties of bone, which have an important role in tissue homeostasis and regeneration, have been frequently neglected in the design of BTE scaffolds. Therefore, in this study, we developed novel hydroxyapatite (HAp)-filled osteoinductive and piezoelectric poly(vinylidene fluoride-co-tetrafluoroethylene) (PVDF-TrFE) nanofibers via electrospinning capable of replicating the tissue's fibrous extracellular matrix (ECM) composition and native piezoelectric properties. The developed PVDF-TrFE/HAp nanofibers had biomimetic collagen fibril-like diameters, as well as enhanced piezoelectric and surface properties, which translated into a better capacity to assist the mineralization process and cell proliferation. The biological cues provided by the HAp nanoparticles enhanced the osteogenic differentiation of seeded human mesenchymal stem/stromal cells (MSCs) as observed by the increased ALP activity, cell-secreted calcium deposition and osteogenic gene expression levels observed for the HAp-containing fibers. Overall, our findings describe the potential of combining PVDF-TrFE and HAp for developing electroactive and osteoinductive nanofibers capable of supporting bone tissue regeneration.

The problem of polyethylene waste - Recent attempts for its mitigation

For the past two decades, with the increase in plastic consumption came a rise in plastic waste, with the bulk of it ending up in landfills, incinerated, recycled or leaking into the environment, especially in aquatic ecosystems. Plastic waste poses a significant environmental threat and a wealth issue due to its non-biodegradability and recalcitrant nature. Polyethylene (PE) remains one of the major utilized polymers in different applications amid all the other types because of its low production costs, simplistic nature prone to be modified and historically predominant researched material. Since the common methods for plastic disposal are troubled by limitations, there is a growing need for more appropriate and environment friendly methods alternatives. This study highlights several ways that can be used to assist PE (bio)degradation and mitigate its waste impact. Biodegradation (microbiological activity driven) and photodegradation (radiation driven) are the most promising for PE waste control. The shape of the material (powder, film, particles, etc.), the medium degradation - composition, additives and pH, temperature and incubation, or exposure times are important in plastic degradation efficiency. Moreover, radiation pretreatment can enhance the biodegradability of PE, providing a promising approach to fighting plastic pollution. This paper relates the most significant results regarding PE degradation studies followed by weight loss (WL) analysis, surface morphology changes, oxidation degree (for photodegradation) and mechanical properties assessment. All these strategies are very promising methods to minimize the polyethylene impact. However, there is still a long way to go through. The degradation kinetics is still low for the currently available biotic or abiotic processes and complete mineralization is thoroughly unseen.

Development of BioPolyurethane Coatings from Biomass-Derived Alkylphenol Polyols-A Green Alternative

Bio-based polyols were obtained from the thermochemical liquefaction of two biomass feedstocks, pinewood and Stipa tenacissima, with conversion rates varying between 71.9 and 79.3 wt.%, and comprehensively characterized. They exhibit phenolic and aliphatic moieties displaying hydroxyl (OH) functional groups, as confirmed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and nuclear magnetic resonance spectroscopy (NMR) analysis. The biopolyols obtained were successfully employed as a green raw material to produce bio-based polyurethane (BioPU) coatings on carbon steel substrates, using, as an isocyanate source, a commercial bio-based polyisocyanate-Desmodur^® Eco N7300. The BioPU coatings were analyzed in terms of chemical structure, the extent of the reaction of the isocyanate species, thermal stability, hydrophobicity, and adhesion strength. They show moderate thermal stability at temperatures up to 100 °C, and a mild hydrophobicity, displaying contact angles between 68° and 86°. The adhesion tests reveal similar pull-off strength values (ca. 2.2 MPa) for the BioPU either prepared with pinewood and Stipa-derived biopolyols (BPUI and BPUII). Electrochemical impedance spectroscopy (EIS) measurements were carried out on the coated substrates for 60 days in 0.05 M NaCl solution. Good corrosion protection properties were achieved for the coatings, with particular emphasis on the coating prepared with the pinewood-derived polyol, which exhibited a low-frequency impedance modulus normalized for the coating thickness of 6.1 × 10¹⁰ Ω cm at the end of the 60 days test, three times higher than for coatings prepared with Stipa-derived biopolyols. The produced BioPU formulations show great potential for application as coatings, and for further modification with bio-based fillers and corrosion inhibitors.

Multicomponent oxide microspheres with designed macroporosity (MICROSCAFS®): a customized platform for chemicals immobilization

A novel versatile, easily recoverable, and recyclable material platform is herein presented, consisting of multicomponent oxide microspheres, of silica-titania and silica-titania-hafnia composition, with tailored interconnected macroporosity (MICROSCAFS®). When functionalized or loaded with desired species, they are potential enablers of emerging applications in environmental remediation, among other fields. We combine emulsion templating for the spherical shape of the particles, with an adapted sol-gel technique involving polymerization-induced phase separation by spinodal decomposition. An advantage of our method regards the employed mix of precursors, which prevents the use of specific gelation additives and porogens and allows a high reproducibility of MICROSCAFS®. We present insight into their formation mechanism using cryo-scanning electron microscopy, and a systematic study of the effect of multiple synthesis parameters on the MICROSCAFS® size and porosity. The composition of the silicon precursors has the most significant effect on fine-tuning the pores size, ranging from the nanometer to the micron scale. Mechanical properties are correlated with morphological features. Larger macroporosity (68% open porosity, estimated by X-ray computed tomography) leads to less stiffness, higher elastic recovery, and compressibility values up to 42%. We believe this study creates a base for consistent custom MICROSCAFS® production, with a design for various future applications.

Evaluation of the Potential of Metakaolin, Electric Arc Furnace Slag, and Biomass Fly Ash for Geopolymer Cement Compositions

The widespread use of geopolymer cement (GPC) has been hindered by a lack of scientific knowledge that still exists regarding its synthesis process. Key points, such as the release of aluminosilicate species from the raw materials and its link to the properties of GPC, have still not been completely studied. As a result, most of the GPC formulations covered in the literature are based on precursors' elemental analysis using XRF (X-ray Fluorescence), or other equivalent analysis methods, and consider that the total aluminosilicate content of the precursors is available for participating in the geopolymerization process, which seems very unlikely. In this study, the amounts of aluminate and silicate species released from metakaolin (MK), electric arc furnace slag (EAFS), and biomass fly ash (BFA) in alkaline dissolution tests were determined by simple spectrophotometric methods. It was found that MK yields the highest aluminosilicate dissolution amount, about 2.1 mmol of silicate + aluminate per gram of MK, while EAFS and BFA yield about 0.53 and 0.32 mmol/g precursor, respectively. These results were used to estimate the total amounts of dissolved aluminosilicates in a series of GPC mortars prepared from these raw materials, which were thereafter subjected to mechanical tests. It was shown that the mortars' compressive strength (which ranged from 1 to 63 MPa) is linearly correlated with their estimated total amount of dissolved aluminosilicates, with the best linear fit yielding a coefficient of determination above 0.99. It was concluded that by using the results of the dissolution tests, the estimation of compressive strength is greatly improved when compared to using the elemental analysis obtained by XRF, which yields a coefficient of determination of 0.88 and a larger dispersion of data points. The results reveal the usefulness of this simple method for evaluating the potential of inorganic industrial waste streams as precursors for GPC.

Super-Strong Hydrogel Composites Reinforced with PBO Nanofibers for Cartilage Replacement

Cartilage replacement materials exhibiting a set of demanding properties such as high water content, high mechanical stiffness, low friction, and excellent biocompatibility are quite difficult to achieve. Here, poly(p-phenylene-2,6-benzobisoxazole) (PBO) nanofibers are combined with polyvinyl alcohol (PVA) to form a super-strong structure with a performance that surpasses the vast majority of previously existing hydrogels. PVA-PBO composites with water contents in the 59-76% range exhibit tensile and compressive moduli reaching 20.3 and 4.5 MPa, respectively, and a coefficient of friction below 0.08. Further, they are biocompatible and support the viability of chondrocytes for 1 week, with significant improvements in cell adhesion, proliferation, and differentiation compared to PVA. The new composites can be safely sterilized by steam heat or gamma radiation without compromising their integrity and overall performance. In addition, they show potential to be used as local delivery platforms for anti-inflammatory drugs. These attractive features make PVA-PBO composites highly competitive engineered materials with remarkable potential for use in the design of load-bearing tissues. Complementary work has also revealed that these composites will be interesting alternatives in other industrial fields where high thermal and mechanical resistance are essential requirements, or which can take advantage of the pH responsiveness functionality.

Biodegradable Microcapsules of Poly(Butylene Adipate-co-Terephthalate) (PBAT) as Isocyanate Carriers and the Effect of the Process Parameters

Poly(butylene adipate-co-terephthalate) (PBAT), a biodegradable flexible, and tough polymer is herein used, for the first time, to encapsulate and protect isocyanate derivatives. Isocyanates are essential building blocks widely employed in the chemical industry for the production of high-performing materials. Microencapsulation of isocyanates eliminates the risks associated with their direct handling and protects them from moisture. In light of this, and having in mind eco-innovative products and sustainability, we present a straightforward process to encapsulate isophorone diisocyanate (IPDI) using this biodegradable polymer. Spherical and core-shell microcapsules (MCs) were produced by an emulsion system combined with the solvent evaporation method. The MCs present a regular surface, without holes or cracks, with a thin shell and high isocyanate loadings, up to 79 wt%. Additionally, the MCs showed very good isocyanate protection if not dispersed in organic or aqueous solutions. Effects of various process parameters were systematically studied, showing that a higher stirring speed (1000 rpm) and emulsifier amount (2.5 g), as well as a smaller PBAT amount (1.60 g), lead to smaller MCs and narrower size distribution.

Water Peel-Off Transfer of Electronically Enhanced, Paper-Based Laser-Induced Graphene for Wearable Electronics

Laser-induced graphene (LIG) has gained preponderance in recent years, as a very attractive material for the fabrication and patterning of graphitic structures and electrodes, for multiple applications in electronics. Typically, polymeric substrates, such as polyimide, have been used as precursor materials, but other organic, more sustainable, and accessible precursor materials have emerged as viable alternatives, including cellulose substrates. However, these substrates have lacked the conductive and chemical properties achieved by conventional LIG precursor substrates and have not been translated into fully flexible, wearable scenarios. In this work, we expand the conductive properties of paper-based LIG, by boosting the graphitization potential of paper, through the introduction of external aromatic moieties and meticulous control of laser fluence. Colored wax printing over the paper substrates introduces aromatic chemical structures, allowing for the synthesis of LIG chemical structures with sheet resistances as low as 5 Ω·sq^-1, translating to an apparent conductivity as high as 28.2 S·cm^-1. Regarding chemical properties, I_D/I_G ratios of 0.28 showcase low defect densities of LIG chemical structures and improve on previous reports on paper-based LIG, where sheet resistance has been limited to values around 30 Ω·sq^-1, with more defect dense and less crystalline chemical structures. With these improved properties, a simple transfer methodology was developed, based on a water-induced peel-off process that efficiently separates patterned LIG structures from the native paper substrates to conformable, flexible substrates, harnessing the multifunctional capabilities of LIG toward multiple applications in wearable electronics. Proof-of concept electrodes for electrochemical sensors, strain sensors, and in-plane microsupercapacitors were patterned, transferred, and characterized, using paper as a high-value LIG precursor for multiples scenarios in wearable technologies, for improved sustainability and accessibility of such applications.

Characterisation of Films Based on Exopolysaccharides from Alteromonas Strains Isolated from French Polynesia Marine Environments

This work assessed the film-forming capacity of exopolysaccharides (EPS) produced by six Alteromonas strains recently isolated from different marine environments in French Polynesia atolls. The films were transparent and resulted in small colour alterations when applied over a coloured surface (ΔEab below 12.6 in the five different colours tested). Moreover, scanning electron microscopy showed that the EPS films were dense and compact, with a smooth surface. High water vapour permeabilities were observed (2.7-6.1 × 10-11 mol m-1 s-1 Pa-1), which are characteristic of hydrophilic polysaccharide films. The films were also characterised in terms of barrier properties to oxygen and carbon dioxide. Interestingly, different behaviours in terms of their mechanical properties under tensile tests were observed: three of the EPS films were ductile with high elongation at break (ε) (35.6-47.0%), low tensile strength at break (Ꞇ) (4.55-11.7 MPa) and low Young's modulus (εm) (10-93 MPa), whereas the other three were stiffer and more resistant with a higher Ꞇ (16.6-23.6 MPa), lower ε (2.80-5.58%), and higher εm (597-1100 MPa). These properties demonstrate the potential of Alteromonas sp. EPS films to be applied in different areas such as biomedicine, pharmaceuticals, or food packaging.

Triclosan and Its Consequences on the Reproductive, Cardiovascular and Thyroid Levels

Hygiene is essential to avoid diseases, and this is thanks to daily cleaning and disinfection habits. Currently, there are numerous commercial products containing antimicrobial agents, and although they are efficient in disinfecting, it is still not known the effect of the constant use of these products on human health. In fact, a massive use of disinfectants has been observed due to COVID-19, but the possible adverse effects are not yet known. Triclosan is one of the antimicrobial agents used in cosmetic products, toothpaste, and disinfectants. This compound is an endocrine disruptor, which means it can interfere with hormonal function, with its estrogenic and androgenic activity having already been stated. Even if the use of triclosan is well-regulated, with the maximum allowed concentration in the European Union of 0.3% (m/m), its effects on human health are still uncertain. Studies in animals and humans suggest the possibility of harmful health outcomes, particularly for the reproductive system, and in a less extent for the cardiovascular and thyroid functions. Thus, the purpose of this review was to analyse the possible implications of the massive use of triclosan, mainly on the reproductive and cardiovascular systems and on the thyroid function, both in animals and humans.

Bioconversion of Terephthalic Acid and Ethylene Glycol Into Bacterial Cellulose by Komagataeibacter xylinus DSM 2004 and DSM 46604

Komagataeibacter xylinus strains DSM 2004 and DSM 46604 were evaluated for their ability to grow and produce bacterial cellulose (BC) upon cultivation on terephthalic acid (TA) and ethylene glycol (EG), which are monomers of the petrochemical-derived plastic polyethylene terephthalate (PET). Both strains were able to utilize TA, EG, and their mixtures for BC synthesis, with different performances. K. xylinus DSM 2004 achieved higher BC production from TA (0.81 ± 0.01 g/L), EG (0.64 ± 0.02 g/L), and TA + EG mixtures (0.6 ± 0.1 g/L) than strain DSM 46604. The latter was unable to utilize EG as the sole carbon source and reached a BC production of 0.16 ± 0.01 g/L and 0.23 ± 0.1 g/L from TA alone or TA + EG mixtures, respectively. Further supplementing the media with glucose enhanced BC production by both strains. During cultivation on media containing TA and EG, rapid pH drop due to metabolization of EG into acidic compounds led to some precipitation of TA that was impregnated into the BC pellicles. An adaptation of the downstream procedure involving BC dissolution in NaOH was used for the recovery of pure BC. The different medium composition tested, as well as the downstream procedure, impacted the BC pellicles’ physical properties. Although no variation in terms of the chemical structure were observed, differences in crystallinity degree and microstructure of the produced BC were observed. The BC produced by K. xylinus DSM 2004 had a higher crystallinity (19–64%) than that of the strain DSM 46604 (17–53%). Moreover, the scanning electron microscopy analysis showed a higher fiber diameter for K. xylinus DSM 2004 BC (46–56 nm) than for K. xylinus DSM 46604 (37–49 nm). Dissolution of BC in NaOH did not influence the chemical structure; however, it led to BC conversion from type I to type II, as well as a decrease in crystallinity. These results demonstrate that PET monomers, TA and EG, can be upcycled into a value-added product, BC, presenting an approach that will contribute to lessening the environmental burden caused by plastic disposal in the environment.

Estimating RNA dynamics using one time point for one sample in a single-pulse metabolic labeling experiment

Background

Over the past decade, experimental procedures such as metabolic labeling for determining RNA turnover rates at the transcriptome-wide scale have been widely adopted and are now turning to single cell measurements. Several computational methods to estimate RNA synthesis, processing and degradation rates from such experiments have been suggested, but they all require several RNA sequencing samples. Here we present a method that can estimate those three rates from a single sample.

Methods

Our method relies on the analytical solution to the Zeisel model of RNA dynamics. It was validated on metabolic labeling experiments performed on mouse embryonic stem cells. Resulting degradation rates were compared both to previously published rates on the same system and to a state-of-the-art method applied to the same data.

Results

Our method is computationally efficient and outputs rates that correlate well with previously published data sets. Using it on a single sample, we were able to reproduce the observation that dynamic biological processes tend to involve genes with higher metabolic rates, while stable processes involve genes with lower rates. This supports the hypothesis that cells control not only the mRNA steady-state abundance, but also its responsiveness, i.e., how fast steady state is reached. Moreover, degradation rates obtained with our method compare favourably with the other tested method.

Conclusions

In addition to saving experimental work and computational time, estimating rates for a single sample has several advantages. It does not require an error-prone normalization across samples and enables the use of replicates to estimate uncertainty and assess sample quality. Finally the method and theoretical results described here are general enough to be useful in other contexts such as nucleotide conversion methods and single cell metabolic labeling experiments.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12859-022-04672-4.

Development of polycarbonate urethane-based materials with controlled diclofenac release for cartilage replacement

Hydrogels are very promising human cartilage replacement materials since they are able to mimic its structure and properties. Besides, they can be used as platforms for drug delivery to reduce inflammatory postsurgical reactions. Polycarbonate urethane (PCU) has been used in orthopedic applications due to its long-term biocompatibility and bio-durability. In this work, PCU-based hydrogels with the ability to release an anti-inflammatory (diclofenac) were developed, for the first time, for such purpose. The materials were reinforced with different amounts of cellulose acetate (CA, 10%, 15%, and 25% w/w) or carbon nanotubes (CNT, 1% and 2% w/w) in order to improve their mechanical properties. Samples were characterized in terms of compressive and tensile mechanical behavior. It was found that 15% CA and 2% CNT reinforcement led to the best mechanical properties. Thus, these materials were further characterized in terms of morphology, wettability, and friction coefficient (CoF). Contrarily to CNTs, the addition of CA significantly increased the material's porosity. Both materials became more hydrophilic, and the CoF slightly increased for PCU + 15%CA. The materials were loaded by soaking with diclofenac, and drug release experiments were conducted. PCU, PCU + 15%CA and PCU + 2%CNT presented similar release profiles, being able to ensure a controlled release of DFN for at least 4 days. Finally, in vitro cytotoxicity tests using human chondrocytes were also performed and confirmed a high biocompatibility for the three studied materials.

Paper-Based Biosensors for COVID-19: A Review of Innovative Tools for Controlling the Pandemic

The appearance and quick spread of the new severe acute respiratory syndrome coronavirus disease, COVID-19, brought major societal challenges. Importantly, suitable medical diagnosis procedures and smooth clinical management of the disease are an emergent need, which must be anchored on novel diagnostic methods and devices. Novel molecular diagnostic tools relying on nucleic acid amplification testing have emerged globally and are the current gold standard in COVID-19 diagnosis. However, the need for widespread testing methodologies for fast, effective testing in multiple epidemiological scenarios remains a crucial step in the fight against the COVID-19 pandemic. Biosensors have previously shown the potential for cost-effective and accessible diagnostics, finding applications in settings where conventional, laboratorial techniques may not be readily employed. Paper- and cellulose-based biosensors can be particularly relevant in pandemic times, for the renewability, possibility of mass production with sustainable methodologies, and safe environmental disposal. In this review, paper-based devices and platforms targeting SARS-CoV-2 are showcased and discussed, as a means to achieve quick and low-cost PoC diagnosis, including detection methodologies for viral genomic material, viral antigen detection, and serological antibody testing. Devices targeting inflammatory markers relevant for COVID-19 are also discussed, as fast, reliable bedside diagnostic tools for patient treatment and follow-up.

Enhanced solar photocatalysis of TiO2 nanoparticles and nanostructured thin films grown on paper

Titanium dioxide nanoparticles and nanostructured thin films were simultaneously synthesized using a microwave-assisted hydrothermal method. The synthesis formed very fine particles, appearing as nanospheres in the 11 nm size range. As for the nanostructured films, they have displayed similar structural characteristics to the nanoparticles, with thickness of 130 nm. These films covered uniformly and homogenously the Whatman paper, while maintaining its flexibility. The materials processed had their photocatalytic activity assessed from rhodamine B degradation under solar radiation (91% degradation after 40 min for the powder material and 68% after 6 h for the nanostructured thin films). Reusability experiments were also carried out, revealing superior performance concerning the Degussa P25, the most common photocatalyst used. The results of the present work can be thought as an option for the existing photocatalysts activated under solar light, namely for water purification, as it simultaneously produces enhanced photocatalytic powders and photocatalytic papers fully disposable and that can be easily recycled.

Macroporosity Control by Phase Separation in Sol-Gel Derived Monoliths and Microspheres

Macroporous and hierarchically macro/mesoporous materials (mostly monoliths and microspheres) have attracted much attention for a variety of applications, such as supporting or enabling materials in chromatography, energy storage and conversion, catalysis, biomedical devices, drug delivery systems, and environmental remediation. A well-succeeded method to obtain these tailored porous materials relies on the sol-gel technique, combined with phase separation by spinodal decomposition, and involves as well emulsification as a soft template, in the case of the synthesis of porous microspheres. Significant advancements have been witnessed, in terms of synthesis methodologies optimized either for the use of alkoxides or metal-salts and material design, including the grafting or immobilization of a specific species (or nanoparticles) to enable the most recent trends in technological applications, such as photocatalysis. In this context, the evolution, in terms of material composition and synthesis strategies, is discussed in a concerted fashion in this review, with the goal of inspiring new improvements and breakthroughs in the framework of porous materials.

Electrical stimulation of neural-differentiating iPSCs on novel coaxial electroconductive nanofibers

Neural tissue engineering strategies are paramount to create fully mature neurons, necessary for new therapeutic strategies for neurological diseases or the creation of reliable in vitro models. Scaffolds can provide physical support for these neurons and enable cues for enhancing neural cell differentiation, such as electrical current. Coaxial electrospinning fibers, designed to fulfill neural cell needs, bring together an electroconductive shell layer (PCL-PANI), able to mediate electrical stimulation of cells cultivated on fibers mesh surface, and a soft core layer (PGS), used to finetune fiber diameter (951 ± 465 nm) and mechanical properties (1.3 ± 0.2 MPa). Those dual functional coaxial fibers are electroconductive (0.063 ± 0.029 S cm-1, stable over 21 days) and biodegradable (72% weigh loss in 12 hours upon human lipase accelerated assay). For the first time, the long-term effects of electrical stimulation on induced neural progenitor cells were studied using such fibers. The results show increase in neural maturation (upregulation of MAP2, NEF-H and SYP), up-regulation of glutamatergic marker genes (VGLUT1 - 15-fold) and voltage-sensitive channels (SCN1α - 12-fold, CACNA1C - 32-fold), and a down-regulation of GABAergic marker (GAD67 - 0.09-fold), as detected by qRT-PCR. Therefore, this study suggest a shift from an inhibitory to an excitatory neural cell profile. This work shows that the PGS/PCL-PANI coaxial fibers here developed have potential applications in neural tissue engineering.

Porous Silica Microspheres with Immobilized Titania Nanoparticles for In-Flow Solar-Driven Purification of Wastewater

In this paper, inorganic silica microspheres with interconnected macroporosity are tested as a platform for designing robust and efficient photocatalytic systems for a continuous flow reactor, enabling a low cost and straightforward purification of wastewater through solar-driven photocatalysis. The photocatalytically active microspheres are prepared by wet impregnation of porous silica scaffolds with Trizma-functionalized anatase titania (TiO2) nanoparticles (NPs). NPs loading of 22 wt% is obtained in the form of a thin and well-attached layer, covering the external surface of the microspheres as well as the internal surface of the pores. The TiO2 loading leads to an increase of the specific surface area by 26%, without impacting the typically interconnected macroporosity (≈60%) of the microspheres, which is essential for an efficient flow of the pollutant solution during the photocatalytic tests. These are carried out in a liquid medium for the decomposition of methyl orange and paracetamol. In addition to photocatalytic activity under continuous flow, the microspheres offer the advantage that they can be easily removed from the reaction medium, which is an appealing aspect for industrial applications. In this work, the typical issues of TiO2 NPs photocatalysts are circumvented, without the need for elaborate chemistries, and for low availability and expensive raw materials.

Paper Microfluidics and Tailored Gold Nanoparticles for Nonenzymatic, Colorimetric Multiplex Biomarker Detection

The plasmonic properties of gold nanoparticles (AuNPs) are a promising tool to develop sensing alternatives to traditional, enzyme-catalyzed reactions. The need for sensing alternatives, especially in underdeveloped areas of the world, has given rise to the application of nonenzymatic sensing approaches paired with cellulosic substrates to biochemical analysis. Herein, we present three individual, low-step, wet-chemistry, colorimetric assays for three target biomarkers, namely, glucose, uric acid, and free cholesterol, relevant in diabetes control and their translation into paper-based assays and microfluidic platforms for multiplexed analysis. For glucose determination, an in situ AuNPs synthesis approach was applied into the developed μPAD, giving semiquantitative measures in the physiologically relevant range. For uric acid and cholesterol determination, modified AuNPs were used to functionalize paper with a gold-on-paper approach with the optical properties changing based on different aggregation degrees and hydrophobic properties of particles dependent on analyte concentration. These paper-based assays show sensitivity ranges and limits of detection compatible for target analyte level determination and detection limits comparable to those of similar enzymatic, colorimetric systems, relying only on plasmonic transduction without the need for enzymatic activity or other chromogenic substrates. The resulting paper-based assays were integrated into a single 3D, multiplex paper-based device using paper microfluidics, showing the capability for performing different colorimetric assays with distinct requirements in terms of sample flow and sample uptake in test zones using a combination of both horizontal and vertical flows inside the same device. The presented device allows for multiparametric, colorimetric measures of different metabolite levels from a single complex sample matrix drop using digital color analysis, showing the potential for development of low-cost, low-complexity tools for diagnostics toward the point-of-care.

Review on Adhesives and Surface Treatments for Structural Applications: Recent Developments on Sustainability and Implementation for Metal and Composite Substrates

Using adhesives for connection technology has many benefits. It is cost-efficient, fast, and allows homogeneous stress distribution between the bonded surfaces. This paper gives an overview on the current state of knowledge regarding the technologically important area of adhesive materials, as well as on emergent related technologies. It is expected to fill some of the technological gaps between the existing literature and industrial reality, by focusing at opportunities and challenges in the adhesives sector, on sustainable and eco-friendly chemistries that enable bio-derived adhesives, recycling and debonding, as well as giving a brief overview on the surface treatment approaches involved in the adhesive application process, with major focus on metal and polymer matrix composites. Finally, some thoughts on the connection between research and development (R&D) efforts, industry standards and regulatory aspects are given. It contributes to bridge the gap between industry and research institutes/academy. Examples from the aeronautics industry are often used since many technological advances in this industry are innovation precursors for other industries. This paper is mainly addressed to chemists, materials scientists, materials engineers, and decision-makers.

Production of medium-chain-length polyhydroxyalkanoates by Pseudomonas chlororaphis subsp. aurantiaca: Cultivation on fruit pulp waste and polymer characterization

Pseudomonas chlororaphis subsp. aurantiaca DSM 19603 was cultivated on apple pulp, a glucose- and fructose-rich waste generated during juice production, to produce medium-chain length polyhydroxyalkanoates. A cell dry mass of 8.74 ± 0.20 g/L, with a polymer content of 49.25 ± 4.08% were attained. The produced biopolymer was composed of 42.7 ± 0.1 mol% 3-hydroxydecanoate, 17.9 ± 1.0 mol% 3-hydroxyoctanoate, 14.5 ± 1.1 mol% 3-hydroxybutyrate, 11.1 ± 0.6 mol% 3-hydroxytetradecanoate, 10.1 ± 0.5 mol% 3-hydroxydodecanoate and 3.7 ± 0.2 mol% 3-hydroxyhexanoate. It presented low glass transition and melting temperatures (-40.9 ± 0.7 °C and 42.0 ± 0.1 °C, respectively), and a degradation temperature of 300.0 ± 0.1 °C, coupled to a low crystallinity index (12.7 ± 2.7%), a molecular weight (Mw) of 1.34 × 10⁵ ± 0.18 × 10⁵ Da and a polydispersity index of 2.70 ± 0.03. The biopolymer's films were dense and had a smooth surface, as demonstrated by Scanning Electron Microscopy. They presented a tension at break of 5.21 ± 1.09 MPa, together with an elongation of 400.5 ± 55.8% and an associated Young modulus of 4.86 ± 1.49 MPa, under tensile tests. These attractive filming properties of this biopolymer could potentially be valorised in several areas such as the fine chemicals industry, biomedicine, pharmaceuticals, or food packaging.

Paper-Based In-Situ Gold Nanoparticle Synthesis for Colorimetric, Non-Enzymatic Glucose Level Determination

Due to its properties, paper represents an alternative to perform point-of-care tests for colorimetric determination of glucose levels, providing simple, rapid, and inexpensive means of diagnosis. In this work, we report the development of a novel, rapid, disposable, inexpensive, enzyme-free, and colorimetric paper-based assay for glucose level determination. This sensing strategy is based on the synthesis of gold nanoparticles (AuNPs) by reduction of a gold salt precursor, in which glucose acts simultaneously as reducing and capping agent. This leads to a direct measurement of glucose without any enzymes or depending on the detection of intermediate products as in conventional enzymatic colorimetric methods. Firstly, we modelled the synthesis reaction of AuNPs to determine the optical, morphological, and kinetic properties and their manipulation for glucose sensing, by determining the influence of each of the reaction precursors towards the produced AuNPs, providing a guide for the manipulation of nucleation and growth. The adaptation of this synthesis into the developed paper platform was tested and calibrated using different standard solutions with physiological concentrations of glucose. The response of the colorimetric signals obtained with this paper-based platform showed a linear behavior until 20 mM, required for glycemic control in diabetes, using the Red × Value/Grey feature combination as a calibration metric, to describe the variations in color intensity and hue in the spot test zone. The colorimetric sensor revealed a detection limit of 0.65 mM, depending on calibration metric and sensitivity of 0.013 AU/mM for a linear sensitivity range from 1.25 to 20 mM, with high specificity for the determination of glucose in complex standards with other common reducing interferents and human serum.

Trans youth in Portugal: gendered embodiments

The lived gendered experience of trans youth constitutes a relatively overlooked aspect of current research. Addressing this gap, this study reveals how young trans people in Portugal define their identities and legitimate their bodies in daily life. Drawing on in-depth interviews with 12 Portuguese trans young people, this study focuses on how trans youth situate themselves within dominant paradigms for understanding (trans)gender identities and embodiment. In doing so, this study engages with wider discussion regarding transgender embodiment that aims to move beyond binary/non-binary gender divisions, as well as privilege the voices and lived experiences of trans people. As the study demonstrates, trans youth are able to (re)construct authentic and coherent gendered selves through the incorporation of a diverse range of frameworks available in contemporary society. Although these frameworks may sometimes seem incompatible and contradictory, trans youth demonstrate conditional forms of agency in the way they (re)create their gender identity and embodiment. By revealing the diversity of trans participant discourses, practices and embodiments of gender, this study makes a key contribution to research on trans youth in Portugal and beyond, as well as broader debates.

Evaluation of temperature and osteotomy speed with piezoelectric system

BACKGROUND

Piezosurgery is an option to realize several clinical and surgical procedures, due to its advantages as precision in osteotomy. This study aims to evaluate the heating and osteotomy speed in bone blocks of ox's shins, to report the best way of its use in the clinical practice.

METHODS

A bone blocks had the dimensions as follow: 20 mm length, 10 mm width, and 5 mm wide. It was evaluated 5 different groups: group LM (low speed and medium pressure); group HM (high speed and medium pressure); group HH (high speed and high pressure); group LH (low speed and high pressure); group LL (low speed and low pressure). The heating increasement was measured with a thermal viewer and the osteotomy was timed when the cut depth reached 5 mm and the whole block detached itself. One-way ANOVA and Tukey tests were adopted to analyze the data and the level of significance was set at a P value of 0.05.

RESULTS

The pressure and speed of the tip, works directly in the generated temperature during osteotomy. The medium pressure level is the most favorable, because high pressure level caused a high increase in heating over the bone and low pressure presented a very long osteotomy time.

CONCLUSIONS

The high speed and medium pressure can be suggested as the most efficient in both standards of time/temperature to realize the osteotomy.

Evaluation of temperature and osteotomy speed with piezoelectric system

BACKGROUND

Piezosurgery is an option to realize several clinical and surgical procedures, due to its advantages as precision in osteotomy. This study aims to evaluate the heating and osteotomy speed in bone blocks of ox's shins, to report the best way of its use in the clinical practice.

METHODS

A bone blocks had the dimensions as follow: 20 mm length, 10 mm width, and 5 mm wide. It was evaluated 5 different groups: group LM (low speed and medium pressure); group HM (high speed and medium pressure); group HH (high speed and high pressure); group LH (low speed and high pressure); group LL (low speed and low pressure). The heating increasement was measured with a thermal viewer and the osteotomy was timed when the cut depth reached 5 mm and the whole block detached itself. One-way ANOVA and Tukey tests were adopted to analyze the data and the level of significance was set at a P value of 0.05.

RESULTS

The pressure and speed of the tip, works directly in the generated temperature during osteotomy. The medium pressure level is the most favorable, because high pressure level caused a high increase in heating over the bone and low pressure presented a very long osteotomy time.

CONCLUSIONS

The high speed and medium pressure can be suggested as the most efficient in both standards of time/temperature to realize the osteotomy.

Three-dimensional chromatin interactions remain stable upon CAG/CTG repeat expansion

Expanded CAG/CTG repeats underlie 13 neurological disorders, including myotonic dystrophy type 1 (DM1) and Huntington's disease (HD). Upon expansion, disease loci acquire heterochromatic characteristics, which may provoke changes to chromatin conformation and thereby affect both gene expression and repeat instability. Here, we tested this hypothesis by performing 4C sequencing at the DMPK and HTT loci from DM1 and HD-derived cells. We find that allele sizes ranging from 15 to 1700 repeats displayed similar chromatin interaction profiles. This was true for both loci and for alleles with different DNA methylation levels and CTCF binding. Moreover, the ectopic insertion of an expanded CAG repeat tract did not change the conformation of the surrounding chromatin. We conclude that CAG/CTG repeat expansions are not enough to alter chromatin conformation in cis. Therefore, it is unlikely that changes in chromatin interactions drive repeat instability or changes in gene expression in these disorders.

Paper-Based Platform with an In Situ Molecularly Imprinted Polymer for β-Amyloid

Alzheimer's disease (AD) is one of the most common forms of dementia affecting millions of people worldwide. Currently, an easy and effective form of diagnosis is missing, which significantly hinders a possible improvement of the patient's quality of life. In this context, biosensors emerge as a future solution, opening the doors for preventive medicine and allowing the premature diagnosis of numerous pathologies. This work presents a pioneering biosensor that combines a bottom-up design approach using paper as a platform for the electrochemical recognition of peptide amyloid β-42 (Aβ-42), a biomarker for AD present in blood, associated with visible differences in the brain tissue and responsible for the formation of senile plaques. The sensor layer relies on a molecularly imprinted polymer as a biorecognition element, created on the carbon ink electrode's surface by electropolymerizing a mixture of the target analyte (Aβ-42) and a monomer (O-phenylenediamine) at neutral pH 7.2. Next, the template molecule was removed from the polymeric network by enzymatic and acidic treatments. The vacant sites so obtained preserved the shape of the imprinted protein and were able to rebind the target analyte. Morphological and chemical analyses were performed in order to control the surface modification of the materials. The analytical performance of the biosensor was evaluated by an electroanalytical technique, namely, square wave voltammetry. For this purpose, the analytical response of the biosensor was tested with standard solutions ranging from 0.1 ng/mL to 1 μg/mL of Aβ-42. The linear response of the biosensor went down to 0.1 ng/mL. Overall, the developed biosensor offered numerous benefits, such as simplicity, low cost, reproducibility, fast response, and repeatability less than 10%. All together, these features may have a strong impact in the early detection of AD.

Parental Knowledge about Healthy Sleep Hygiene practices in Children under 6 Year Old: an Exploratory Study

Introduction Children aged 5 to 12 years old needs, at least, 10-11 hours of sleep. Nowadays, children under 6 years old become more interested in TV, computers and in Internet which can lead to difficulty falling asleep. Parent knowledge about child sleep hygiene can influence parent capacity to promote healthy sleep habits, and should be supported by accurate information.

Objectives To analyse parents knowledge of children sleep practices.

Methodology A convenience sample of parents (n = 201) of children from three schools in a northern city of Portugal completed the "Sleep Ideas" Parent Survey on child sleep habits and parental basic sleep knowledge, beliefs and attitudes regarding sleep as a health behaviour.

Results Of the 201 analysed surveys (response rate 67 %), 33.8 % are from parents of children aged under 3 years old, 19.4 % of children with 3 years older, 24.4 % of children with 4 years old, 16.4 % of children with 5 years old and 6.0 % of children with 6 years old. In general, the percentage of correct answers was 84.8 %. Regarding children age, the percentage of correct answers ranged between 77.9 to 86.2 %, being the parents of children with 6 years old those who had the highest percentage of incorrect answers (22.1 %) and, on the other hand, the parents of children with 3 years old those who had the lowest percentage of incorrect answers (13.8 %). The answer with the highest percentage of incorrect answers, in all parents, was “Making a physical effort before going to sleep makes falling asleep easier” (46.8 %).

Conclusion In this study, parents revealed a very reasonable knowledge about sleep, which suggests a good capability to influence positively children’s habits. Parents with high sleep knowledge are more able to promote healthy sleep hygiene habits. Further studies are warranted to promote a better understanding of all the determinant dimensions for good sleeping habits.

Implementation of a Sleep Hygiene Program in 4 - 6 Year Old Portuguese Children: the “It is Time to Sleep” Project First Results

Introduction Sleep, as one of the most determining and present factors in our life, is fundamental for humans, and especially during childhood: it is indispensable for good cognitive, physical and emotional development.

Objectives Designed in the scope of the Portuguese National School Health Program, the objectives of this project were to promote adequate sleep routines, raise awareness of children’s sleep deprivation and to the consequences of an abusive contact with technologies. At the end of this activity, children should be able to recognize the importance of these dimensions.

Methodology The formative activity, performed by 2 school nurses, was applied to 104 children (from 3 different schools from a northern city of Portugal), with 4 (41.3 %), 5 (44.2 %) and 6 years old (14.4 %), and lasted 45 minutes. The project comprises 4 stages: the first one relates to nurses and project theme presentation; the second one is the implementation of a theatre where major issues of the project are presented, namely the importance of sleep and nap, sleep hygiene rules, consequences of sleep deprivation and the influence of technologies on sleep; the third one is the discussion of the main ideas using the song "Sleep Hour"; at the end, a questionnaire was applied to assess children knowledge about sleep hygiene habits divided into six questions with two images each, in which one corresponds to a healthy practice and the other does not.

Results The percentage of correct answers ranged between 96.6 to 98.3 %, suggesting that the formative activity had a positive impact on children’s knowledge about healthy sleep hygiene habits. The 2 questions on which the rate of incorrect answers was higher relate to the fact that sleeping with parents is better than sleeping alone (6.3 %) and that watching TV before going to sleep is a better option than reading a story (4.4 %).

Conclusion This intervention has given children important knowledge about healthy sleep hygiene habits, resulting in its understanding through an approach tailored to their age.

Low Temperature Dissolution of Yeast Chitin-Glucan Complex and Characterization of the Regenerated Polymer

Chitin-glucan complex (CGC) is a copolymer composed of chitin and glucan moieties extracted from the cell-walls of several yeasts and fungi. Despite its proven valuable properties, that include antibacterial, antioxidant and anticancer activity, the utilization of CGC in many applications is hindered by its insolubility in water and most solvents. In this study, NaOH/urea solvent systems were used for the first time for solubilization of CGC extracted from the yeast Komagataella pastoris. Different NaOH/urea ratios (6:8, 8:4 and 11:4 (w/w), respectively) were used to obtain aqueous solutions using a freeze/thaw procedure. There was an overall solubilization of 63-68%, with the highest solubilization rate obtained for the highest tested urea concentration (8 wt%). The regenerated polymer, obtained by dialysis of the alkali solutions followed by lyophilization, formed porous macrostructures characterized by a chemical composition similar to that of the starting co-polymer, although the acetylation degree decreased from 61.3% to 33.9-50.6%, indicating that chitin was converted into chitosan, yielding chitosan-glucan complex (ChGC). Consistent with this, there was a reduction of the crystallinity index and thermal degradation temperature. Given these results, this study reports a simple and green procedure to solubilize CGC and obtain aqueous ChGC solutions that can be processed as novel biomaterials.

Splicing of enhancer-associated lincRNAs contributes to enhancer activity

Transcription is common at active mammalian enhancers sometimes giving rise to stable enhancer-associated long intergenic noncoding RNAs (elincRNAs). Expression of elincRNA is associated with changes in neighboring gene product abundance and local chromosomal topology, suggesting that transcription at these loci contributes to gene expression regulation in cis Despite the lack of evidence supporting sequence-dependent functions for most elincRNAs, splicing of these transcripts is unexpectedly common. Whether elincRNA splicing is a mere consequence of cognate enhancer activity or if it directly impacts enhancer function remains unresolved. Here, we investigate the association between elincRNA splicing and enhancer activity in mouse embryonic stem cells. We show that multi-exonic elincRNAs are enriched at conserved enhancers, and the efficient processing of elincRNAs is strongly associated with their cognate enhancer activity. This association is supported by their enrichment in enhancer-specific chromatin signatures; elevated binding of co-transcriptional regulators; increased local intra-chromosomal DNA contacts; and strengthened cis-regulation on target gene expression. Our results support the role of efficient RNA processing of enhancer-associated transcripts to cognate enhancer activity.

Polycaprolactone microcapsules containing citric acid and naringin for plant growth and sustainable agriculture: physico-chemical properties and release behavior

Plant growth promoting rhizobacteria (PGPR) is an alternative to chemical fertilizers for sustainable, environment friendly agriculture. There is a need to develop strategies to potentiate the interaction between rhizobacteria and plants. Flavonoids and organic acids (components of root exudates) play specific beneficial roles as carbon sources and signal molecules in the plant - rhizobacteria interactions. The goal of this work is to encapsulate signal molecules, namely citric acid and naringin, an organic acid and a flavonoid, respectively, by a biodegradable polymer, polycaprolactone (PCL), in order to maintain the stability and activity of those signal molecules and enable their slow or controlled release over a selected period of time, according to the needs of the plants. This approach is expected to potentiate food crops, namely peanut crop, in adverse environmental conditions (water deficit), by promoting the beneficial interaction between the peanut plant (A. hypogaea) and rhizobacteria. The microcapsules (MCs) are obtained by an emulsion process combined with solvent evaporation technique and are characterized by scanning electron microscopy, thermogravimetry and Fourier transformed infrared spectroscopy. The kinetics of in vitro release of encapsulated molecules, in a period where the uptake of the compound in plants can occur, is studied. The encapsulation synthesis parameters that lead to the best encapsulation process yield and efficiency, as well as to the best final performance in terms of release, are identified. The effect of pH and molecular weight of PCL is found to mediate the release properties of the molecules for different types of soil. PCL 45000 Mw dissolved at 16% in dichloromethane leads to an encapsulation efficiency of 75% and the resulting MCs containing naringin exhibit a slow release profile for 30 days, unmodified by pH, enabling their use in soils of different characteristics. This research makes possible the manufacturing of smart materials for sustainable agriculture practices.

Functionalizing nanoparticles with cancer-targeting antibodies: A comparison of strategies

Standard cancer therapies sometimes fail to deliver chemotherapeutic drugs to tumor cells in a safe and effective manner. Nanotechnology takes the lead in providing new therapeutic options for cancer due to major potential for selective targeting and controlled drug release. Antibodies and antibody fragments are attracting much attention as a source of targeting ligands to bind specific receptors that are overexpressed on cancer cells. Therefore, researchers are devoting time and effort to develop targeting strategies based on nanoparticles functionalized with antibodies, which hold great promise to enhance therapeutic efficacy and circumvent severe side effects. Several methods have been described to immobilize antibodies on the surface of nanoparticles. However, selecting the most appropriate for each application is challenging but also imperative to preserve antigen binding ability and yield stable antibody-conjugated nanoparticles. From this perspective, we aim to provide considerable knowledge on the most widely used methods of functionalization that can be helpful for decision-making and design of conjugation protocols as well. This review summarizes adsorption, covalent conjugation (carbodiimide, maleimide and "click" chemistries) and biotin-avidin interaction, while discussing the advantages, limitations and relevant therapeutic approaches currently under investigation.

Demonstration of the ability of the bacterial polysaccharide FucoPol to flocculate kaolin suspensions

In this study, the flocculation properties of FucoPol, a bacterial extracellular polysaccharide, were investigated. FucoPol is a high molecular weight polymer and negatively charged due to the presence of glucuronic acid and the acyl groups succinyl and pyruvyl. High flocculation rate values (>70%) were achieved with a low bioflocculant dosage of 1 mg/L, for pH values in the range 3-5 and temperature within 15-20°C. The bioflocculant was also shown to be stable after freezing/thawing and heating up to 100°C. Given the polymer's anionic character, the size of flocs formed and their surface profile, bridging seems to be the main flocculation mechanism of FucoPol. This study demonstrated that FucoPol is a promising natural, biodegradable and biocompatible alternative to the currently used synthetic or inorganic hazardous products, with potential to be used as a novel flocculation agent in several applications, such as water treatment, food or mining. Further studies will involve evaluating the reduction of cation dosage on flocculation efficiency, as well as testing the applicability of FucoPol to flocculate different types of suspended solids, such as, for example, activated carbons, soil solids or yeast cells.

The MITF-SOX10 regulated long non-coding RNA DIRC3 is a melanoma tumour suppressor

The MITF and SOX10 transcription factors regulate the expression of genes important for melanoma proliferation, invasion and metastasis. Despite growing evidence of the contribution of long noncoding RNAs (lncRNAs) in cancer, including melanoma, their functions within MITF-SOX10 transcriptional programmes remain poorly investigated. Here we identify 245 candidate melanoma associated lncRNAs whose loci are co-occupied by MITF-SOX10 and that are enriched at active enhancer-like regions. Our work suggests that one of these, Disrupted In Renal Carcinoma 3 (DIRC3), may be a clinically important MITF-SOX10 regulated tumour suppressor. DIRC3 depletion in human melanoma cells leads to increased anchorage-independent growth, a hallmark of malignant transformation, whilst melanoma patients classified by low DIRC3 expression have decreased survival. DIRC3 is a nuclear lncRNA that activates expression of its neighbouring IGFBP5 tumour suppressor through modulating chromatin structure and suppressing SOX10 binding to putative regulatory elements within the DIRC3 locus. In turn, DIRC3 dependent regulation of IGFBP5 impacts the expression of genes involved in cancer associated processes and is needed for DIRC3 control of anchorage-independent growth. Our work indicates that lncRNA components of MITF-SOX10 networks are an important new class of melanoma regulators and candidate therapeutic targets that can act not only as downstream mediators of MITF-SOX10 function but as feedback regulators of MITF-SOX10 activity.

Exhibition of Local but Not Systemic Induced Phenolic Defenses in Vitis vinifera L. Affected by Brown Wood Streaking, Grapevine Leaf Stripe, and Apoplexy (Esca Complex)

Balance between constitutive and induced responses provides plants flexibility to cope with biotic stresses. This study tested the hypothesis that invasion of grapevine wood by esca-associated fungi induces the production of defensive compounds as part of locally- and systemically-induced responses. In a vineyard, different symptomatic expressions of "Esca complex" in Vitis vinifera L. 'Malvasia' were evaluated in annual inspections. Then, levels of phenolics and fatty acids were determined in asymptomatic leaves of brown wood streaking (BWS) and grapevine leaf stripe (GLSD) vines, and in symptomatic leaves of GLSD and apoplectic vines; the results were compared with levels in healthy vines. In asymptomatic leaves of BWS and some GLSD vines, levels of phenolics decreased, independent of the total phenolic group. Such responses were usually associated with an increase in levels of linoleic, γ-linolenic and arachidonic acids, well-known signal transduction mediators. In symptomatic leaves, levels of phenolics increased, which is consistent with a locally-induced response; the onset of symptoms coincided with the highest increases e.g., 35% for quercetin-3-O-glucuronide. Thus, the long latency period between trunk invasion by fungi and visible foliar damage and the year-to-year fluctuation in symptomatic expressions observed with "Esca complex" might be partially attributed to a better utilization of constitutive defenses.