Bone fragment or bone powder? ATR-FTIR spectroscopy-based comparison of chemical composition and DNA preservation of bones after 10 years in a freezer.

Freezing bone samples to preserve their biomolecular properties for various analyses at a later time is a common practice. Storage temperature and freeze-thaw cycles are well-known factors affecting degradation of molecules in the bone, whereas less is known about the form in which the tissue is most stable. In general, as little intervention as possible is advised before storage. In the case of DNA analyses, homogenization of the bone shortly before DNA extraction is recommended. Because recent research on the DNA yield from frozen bone fragments and frozen bone powder indicates better DNA preservation in the latter, the aim of the study presented here was to investigate and compare the chemical composition of both types of samples (fragments versus powder) using ATR-FTIR spectroscopy. Pairs of bone fragments and bone powder originating from the same femur of 57 individuals from a Second World War mass grave, stored in a freezer at - 20 °C for 10 years, were analyzed. Prior to analysis, the stored fragments were ground into powder, whereas the stored powder was analyzed without any further preparation. Spectroscopic analysis was performed using ATR-FTIR spectroscopy. The spectra obtained were processed and analyzed to determine and compare the chemical composition of both types of samples. The results show that frozen powdered samples have significantly better-preserved organic matter and lower concentrations of B-type carbonates, but higher concentrations of A-type carbonates and stoichiometric apatite. In addition, there are more differences in the samples with a low DNA degradation index and less in the samples with a high DNA degradation index. Because the results are inconsistent with the current understanding of bone preservation, additional research into optimal preparation and long-term storage of bone samples is necessary.

Separating forensic, WWII, and archaeological human skeletal remains using ATR-FTIR spectra.

ATR-FTIR spectroscopy is a fast and accessible, minimally or non-destructive technique which provides information on physiochemical characteristics of analyzed materials. In forensic and archaeological sciences, it is commonly used for answering numerous questions, including the archaeological or forensic context of the human skeletal remains. In this research, the accuracy of ATR-FTIR-obtained spectra for separation between forensic, WWII, and archaeological human skeletal remains was investigated. Building from the previously proposed methodological procedures, various ratio-based and whole spectra separation procedures were applied, carefully analyzed, and evaluated. Results showed that employing whole spectral domains works best for the separation of archaeological, WWII, and forensic samples, even with samples of highly variable origin. Principal component analysis (PCA) further highlighted the necessity of acknowledging all the major components in the remains: amides, phosphates, and carbonates for the separation. Most influential proved to be amide I, namely its secondary structure, which presented well-preserved and organized collagen structure in forensic and WWII samples, while highly degraded in archaeological samples. Using the whole spectral domain for separation between samples from different contexts proved to be fast and simple, with no manipulation beyond baseline correction and normalization of spectra necessary. However, a dataset with samples of known origin is required for the learning model and predictions. A less accurate alternative is separation based on combining ratios of peaks correlating to organics and minerals in the bone, which eliminated overlapping and managed to classify the majority of the samples correctly as archaeological, WWII, or forensic.

A Unique Interactive Nanostructure Knitting based Passive Sampler Adsorbent for Monitoring of Hg2+ in Water.

This work reports the development of ultralight interwoven ultrathin graphitic carbon nitride (g-CN) nanosheets for use as a potential adsorbent in a passive sampler (PAS) designed to bind Hg2+ ions. The g-CN nanosheets were prepared from bulk g-CN synthesised via a modified high-temperature short-time (HTST) polycondensation process. The crystal structure, surface functional groups, and morphology of the g-CN nanosheets were characterised using a battery of instruments. The results confirmed that the as-synthesized product is composed of few-layered nanosheets. The adsorption efficiency of g-CN for binding Hg2+ (100 ng mL-1) in sea, river, rain, and Milli-Q quality water was 89%, 93%, 97%, and 100%, respectively, at natural pH. Interference studies found that the cations tested (Co2+, Ca2+, Zn2+, Fe2+, Mn2+, Ni2+, Bi3+, Na+, and K+) had no significant effect on the adsorption efficiency of Hg2+. Different parameters were optimised to improve the performance of g-CN such as pH, contact time, and amount of adsorbent. Optimum conditions were pH 7, 120 min incubation time and 10 mg of nanosheets. The yield of nanosheets was 72.5%, which is higher compared to other polycondensation processes using different monomers. The g-CN sheets could also be regenerated up to eight times with only a 20% loss in binding efficiency. Overall, nano-knitted g-CN is a promising low-cost green adsorbent for use in passive samplers or as a transducing material in sensor applications.

The influence of nano-ZnO application methods on UV protective properties of cotton.

The influence of different application methods on UV protective properties of white and dyed cotton functionalized with ZnO nanoparticles (nano-ZnO) was investigated. The methods differ in application procedure, time of treatment and auxiliaries used in the treating bath. The ultraviolet protection factor (UPF) was determined for untreated and functionalized samples. The presence of nano-ZnO on fibres was investigated using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The content of Zn was determined with energy-dispersive X-ray spectroscopy (EDS) and inductively coupled plasma mass spectrometry (ICP-MS). Dynamic light scattering (DLS) was used for particle size measurements in the prepared solutions. The results show that UV protection of cotton increases with a higher content and uniform distribution of nano-ZnO on the samples and that dyeing increases the loading capacity of cotton towards nano-ZnO. One of the methods (Method IV) gave remarkable results giving cotton an excellent UV protection whether it was dyed or not.

The mysteries of DNA preservation in bone: A comparative study of petrous bones and metacarpal epiphyses using ATR-FTIR spectroscopy.

A comparative analysis of 26 petrous bones and epiphyses of metacarpals from the Second World War era revealed no significant differences in DNA yield or success in STR typing. This unexpected parity in DNA preservation between the petrous bone, a renowned source of endogenous DNA in skeletal remains, and the epiphyses of metacarpals, which are porous and susceptible to taphonomic changes, is surprising. In this study, we introduced ATR-FTIR spectroscopy as an approach to unravel the correlation between bone molecular structure and DNA preservation. Metacarpals and petrous bones with same taphonomic history were sampled and prepared for DNA analyses. While one portion of the sample was used for DNA analysis, the other underwent ATR-FTIR spectroscopic examination. The normalized spectra and FTIR indices between the epiphyses of metacarpals and petrous bones were compared. Because the taphonomic history of the remains used is relatively short and stable, the ATR-FTIR spectroscopy unveiled subtle structural differences between the two bone types. Petrous bones exhibited higher mineralization, whereas epiphyses contained more organic matter. The unexpected preservation of DNA in the epiphyses of metacarpals can likely be attributed to the presence of soft tissue remnants within the trabeculae. Here observed differences in the molecular structure of bones indicate there are different mechanisms enabling DNA preservation in skeletal tissues.

Janus nanocellulose membrane by nitrogen plasma: Hydrophilicity to hydrophobicity selective switch.

Cellulose nanofibrils are one of the keystone materials for sustainable future, yet their poor water repellency hinders their push into industrial applications. Due to complexity and poor economical outcome and/or processing toxicity of the existing hydrophobization methods, nanocellulose loses against its antagonist plastic in medical and food industries. Herein, we demonstrate for the first time the "one-side selective water-repellency activation" in nanocellulose membranes by the means of mild N2-plasma treatment, exhibiting lowest wettability after 20 s of treatment. Hydrophobicity and accompanying Janus character were justified by the topological, chemical and structural reorganizations in cellulose nanofibrils. The findings suggest that the mechanism behind the hydrophilic/hydrophobic change primarily relies on the interplay between OH removal and appearance of SiCH3, originating from the polysiloxanes-based substrate, as well as complementary CNH2 groups formation. First-principles calculations show that NH2 groups moderately increase hydrophobicity, while various SiCH3 substitutions wholly change the character of the surface to repel water. Using nitrogen is shown to be crucial, as N(H)Si(CH3)3 groups induce greater hydrophobicity than simple OSi(CH3)3. Finally, the obtained materials absorb water on the hydrophilic side, while remaining hydrophobic on the other, exhibit high tensile strength, and protection against UV light, demonstrating applicability over wide range of applications.

Antibacterial evaluation of different prosthetic liner textiles coated by CuO nanoparticles.

Prosthetic liners are mainly used as an interface between residual limbs and prosthetic sockets to minimize physical and biological damage to soft tissue. However, the closed and moist conditions within liners and the amputee's skin provide a suitable environment for bacterial growth to cause infections. This study aimed to coat a comprehensive variant material with copper oxide nanoparticles (CuO NPs) and compare their surface analysis and antibacterial properties. These materials were covered with CuO NPs solution at a concentration of 70 µg mL-1 to achieve this purpose. After drying, their surface characteristics were analyzed by measuring zeta potential, contact angle, surface roughness, and fiber arrangement. Cu-released concentration from the coatings into the acetate buffer solution by inductively coupled plasma mass spectrometry indicated that lycra and nylon quickly released Cu ions to concentrations up to ∼0.2 µg mL-1 after 24 h, causing low metabolic activity of human bone-marrow mesenchymal stem cells (bMSC) in the indirect assay. Antibacterial activity of the coated specimens was evaluated by infecting their surfaces with the Gram-positive bacteria Staphylococcus epidermidis, reporting a significant ∼40 % reduction of metabolic activity for x-dry after 24 h; in addition, the number of viable bacterial colonies adhered to the surface of this material was reduced by ∼23 times in comparison with non-treated x-dry that were visually confirmed by scanning electron microscope. In conclusion, CuO NPs x-dry shows optimistic results to pursue further experiments due to its slow speed of Cu release and prolonged antibacterial activity, as well as its compatibility with human cells.

Poly(Allylamine Hydrochloride) and ZnO Nanohybrid Coating for the Development of Hydrophobic, Antibacterial, and Biocompatible Textiles.

In healthcare facilities, infections caused by Staphylococcus aureus (S. aureus) from textile materials are a cause for concern, and nanomaterials are one of the solutions; however, their impact on safety and biocompatibility with the human body must not be neglected. This study aimed to develop a novel multilayer coating with poly(allylamine hydrochloride) (PAH) and immobilized ZnO nanoparticles (ZnO NPs) to make efficient antibacterial and biocompatible cotton, polyester, and nylon textiles. For this purpose, the coated textiles were characterized with profilometry, contact angles, and electrokinetic analyzer measurements. The ZnO NPs on the textiles were analyzed by scanning electron microscopy and inductively coupled plasma mass spectrometry. The antibacterial tests were conducted with S. aureus and biocompatibility with immortalized human keratinocyte cells. The results demonstrated successful PAH/ZnO coating formation on the textiles, demonstrating weak hydrophobic properties. Furthermore, PAH multilayers caused complete ZnO NP immobilization on the coated textiles. All coated textiles showed strong growth inhibition (2-3-log reduction) in planktonic and adhered S. aureus cells. The bacterial viability was reduced by more than 99%. Cotton, due to its better ZnO NP adherence, demonstrated a slightly higher antibacterial performance than polyester and nylon. The coating procedure enables the binding of ZnO NPs in an amount (<30 µg cm-2) that, after complete dissolution, is significantly below the concentration causing cytotoxicity (10 µg mL-1).

The posterity of Zebrafish in paradigm of in vivo molecular toxicological profiling.

The aggrandised advancement in utility of advanced day-to-day materials and nanomaterials has raised serious concern on their biocompatibility with human and other biotic members. In last few decades, understanding of toxicity of these materials has been given the centre stage of research using many in vitro and in vivo models. Zebrafish (Danio rerio), a freshwater fish and a member of the minnow family has garnered much attention due to its distinct features, which make it an important and frequently used animal model in various fields of embryology and toxicological studies. Given that fertilization and development of zebrafish eggs take place externally, they serve as an excellent model organism for studying early developmental stages. Moreover, zebrafish possess a comparable genetic composition to humans and share almost 70% of their genes with mammals. This particular model organism has become increasingly popular, especially for developmental research. Moreover, it serves as a link between in vitro studies and in vivo analysis in mammals. It is an appealing choice for vertebrate research, when employing high-throughput methods, due to their small size, swift development, and relatively affordable laboratory setup. This small vertebrate has enhanced comprehension of pathobiology and drug toxicity. This review emphasizes on the recent developments in toxicity screening and assays, and the new insights gained about the toxicity of drugs through these assays. Specifically, the cardio, neural, and, hepatic toxicology studies inferred by applications of nanoparticles have been highlighted.

Comparison of DNA preservation and ATR-FTIR spectroscopy indices of cortical and trabecular bone of metacarpals and metatarsals.

Shape, size, composition, and function of the bones in the human body vary on the macro, micro and nanoscale. This can influence changes caused by taphonomy and post-mortem preservation, including DNA. Highly mineralised compact bone is less susceptible to taphonomic factors than porous trabecular bone. Some studies imply that DNA can be better preserved in trabecular bone, due to remnants of the soft tissue or bacteria better digesting organic matter while not digesting DNA. The aim of this study was to understand the differences between compact (diaphyses) and trabecular (epiphyses) bone on a molecular level and thus the reasons for the better preservation of the DNA in the trabecular bone. The powder obtained from epiphyses and diaphyses of metacarpals and metatarsals was analysed using ATR-FTIR spectroscopy and compared. Samples with poorest DNA preservation originated from diaphyses, predominantly of metatarsals. They were characterised by higher concentrations of phosphates and crystallinity, while lower collagen quality in comparison to samples with the best DNA preservation. Epiphyses presented higher concentrations of better-preserved collagen while diaphyses had higher concentrations of carbonates and phosphates and higher crystallinity. Due to better-preserved collagen in the epiphyses, the soft tissue remnants hypothesis seems more likely than the bacteria hypothesis.

Emerging and Promising Multifunctional Nanomaterial for Textile Application Based on Graphitic Carbon Nitride Heterostructure Nanocomposites.

Nanocomposites constructed with heterostructures of graphitic carbon nitride (g-C3N4), silver (Ag), and titanium dioxide (TiO2) have emerged as promising nanomaterials for various environmental, energy, and clinical applications. In the field of textiles, Ag and TiO2 are already recognized as essential nanomaterials for the chemical surface and bulk modification of various textile materials, but the application of composites with g-C3N4 as a green and visible-light-active photocatalyst has not yet been fully established. This review provides an overview of the construction of Ag/g-C3N4, TiO2/g-C3N4, and Ag/TiO2/g-C3N4 heterostructures; the mechanisms of their photocatalytic activity; and the application of photocatalytic textile platforms in the photochemical activation of organic synthesis, energy generation, and the removal of various organic pollutants from water. Future prospects for the functionalization of textiles using g-C3N4-containing heterostructures with Ag and TiO2 are highlighted.

Dissecting giant hailstones: A glimpse into the troposphere with its diverse bacterial communities and fibrous microplastics.

The formation of giant hailstones is a rare weather event that has devastating consequences in inhabited areas. This hazard has been occurring more frequently and with greater size of hailstones in recent years, and thus needs to be better understood. While the generally accepted mechanism is thought to be a process similar to the formation of smaller hailstones but with exceptional duration and stronger updrafts, recent evidence suggests that biotic and abiotic factors also influence the growth of these unusually large ice chunks. In this study, we improved these findings by determining the distribution of a wide variety of these factors throughout the hail volume and expanding the search to include new particles that are common in the environment and are of anthropogenic origin. We melted the concentric layers of several giant hailstones that fell to the ground over a small region in Slovenia in 2019. The samples, up to 13 cm in diameter, were analyzed for biotic and abiotic constituents that could have influenced their formation. Using 16S rRNA-based metagenomics approaches, we identified a highly diverse bacterial community, and by using scanning electron microscopy and Raman spectroscopy, we found natural and synthetic fibers concentrated in the cores of the giant hailstones. For the first time, we were able to detect the existence of microplastic fibers in giant hailstones and determine the changes in the distribution of sand within the volume of the samples. Our results suggest that changes in the composition of hail layers and their great diversity are important factors that should be considered in research. It also appears that anthropogenic microfiber pollutants were a significant factor in the formation of the giant hailstones analyzed in this study.

Boosting Copper Biocidal Activity by Silver Decoration and Few-Layer Graphene in Coatings on Textile Fibers.

The outbreak of the Coronavirus disease 2019 (COVID-19) pandemic has highlighted the importance of developing antiviral surface coatings that are capable of repelling pathogens and neutralizing them through self-sanitizing properties. In this study, a novel coating design based on few-layer graphene (FLG) is proposed and silver-decorated micro copper flakes (CuMF) that exhibit both antibacterial and antiviral properties. The role of sacrificial anode surfaces and intrinsic graphene defects in enhancing the release of metal ions from CuMF embedded in water-based binders is investigated. In silico analysis is conducted to better understand the molecular interactions of pathogen-repelling species with bacterial or bacteriophage proteins. The results show that the optimal amount of CuMF/FLG in the coating leads to a significant reduction in bacterial growth, with reductions of 3.17 and 9.81 log for Staphylococcus aureus and Escherichia coli, respectively. The same coating also showed high antiviral efficacy, reducing bacteriophage phi6 by 5.53 log. The antiviral efficiency of the coating is find to be doubled compared to either micro copper flakes or few-layer graphene alone. This novel coating design is versatile and can be applied to various substrates, such as personal protective clothing and face masks, to provide biocidal activity against both bacterial and viral pathogens.

Eco-Friendly Approach to Produce Durable Multifunctional Cotton Fibres Using TiO2, ZnO and Ag NPs.

The development of durable multifunctional properties is crucial for the production of high-performance technical textiles. In this work, a novel, environmentally friendly and facile method was developed for the chemical modification of cotton fabric by in situ biosynthesis of Ag NPs in the presence of sumac leaf extract as a reducing agent on TiO2, ZnO and TiO2 + ZnO previously applied to cotton fibres. The results showed that the presence of TiO2, ZnO and TiO2 + ZnO significantly increased the concentrations of the synthesised Ag NPs on the cotton fibres compared to the one-component Ag coating. This resulted in excellent antimicrobial properties of the TiO2/Ag, ZnO/Ag and TiO2 + ZnO/Ag composites even after 25 washes. While the TiO2 and ZnO particles in the composite were incompatible, the synergistic effect among Ag, TiO2 and ZnO in the composites resulted in excellent UV blocking properties of the coatings before and after 25 washes. Since the biosynthesis of Ag NPs was accompanied by a yellow-brown colouration of the samples, the photocatalytic self-cleaning of the composite coating could not be determined from the photodegradation rate of the coffee stains. This research provides a new environmentally friendly approach to producing durable antimicrobial and UV blocking coatings on cotton fibres.

Correlating Structural Properties with Electrochemical Behavior of Non-graphitizable Carbons in Na-Ion Batteries.

We report on a detailed structural versus electrochemical property investigation of the corncob-derived non-graphitizable carbons prepared at different carbonization temperatures using a combination of structural characterization methodology unique to this field. Non-graphitizable carbons are currently the most viable option for the negative electrode in sodium-ion batteries. However, many challenges arise from the strong dependence of the precursor's choice and carbonization parameters on the evolution of the carbon matrix and its resulting electrochemistry. We followed structure development upon the increase in carbonization temperature with thorough structural characterization and electrochemical testing. With the increase of carbonization temperature from 900 to 1600 °C, our prepared materials exhibited a trend toward increasing structural order, an increase in the specific surface area of micropores, the development of ultramicroporosity, and an increase in conductivity. This was clearly demonstrated by a synergy of small- and wide-angle X-ray scattering, scanning transmission electron microscopy, and electron-energy loss spectroscopy techniques. Three-electrode full cell measurements confirmed incomplete desodiation of Na+ ions from the non-graphitizable carbons in the first cycle due to the formation of a solid-electrolyte interface and Na trapping in the pores, followed by a stable second cycle. The study of cycling stability over 100 cycles in a half-cell configuration confirmed the observed high irreversible capacity in the first cycle, which stabilized to a slow decrease afterward, with the Coulombic efficiency reaching 99% after 30 cycles and then stabilizing between 99.3 and 99.5%. Subsequently, a strong correlation between the determined structural properties and the electrochemical behavior was established.

Novel Green In Situ Synthesis of ZnO Nanoparticles on Cotton Using Pomegranate Peel Extract.

This work presents the novel and entirely green in situ synthesis of zinc oxide nanoparticles (ZnO-NP) on cotton fabric. Pomegranate peel extract was used as a reducing agent and wood ash extract was used as an alkali source for the formation of ZnO-NP from zinc acetate. Four different synthesis methods, which varied in drying between immersion of fabric in the active solutions for synthesis and the use of padding and ultrasonication, were investigated to evaluate the most suitable one to achieve excellent ultraviolet (UV) protective properties of the functionalized textile. For comparison, the cotton fabrics were also functionalized with each active solution separately or in a combination of two (i.e., Zn-acetate and plant extract). Scanning electron microscopy (SEM), inductively coupled plasma mass spectroscopy (ICP-MS), Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD) analysis, and atomic force microscopy (AFM) confirm the successful formation of ZnO-NP on cotton. Among the synthesis methods, the method that included continuous drying of the samples between immersion in the active solutions for synthesis (Method 4) was found to be the most suitable to deliver uniformly impregnated cotton fibers with numerous small ZnO wurtzite structured crystals and excellent UV protection, with a UV protection factor of 154.0. This research presents an example of a green circular economy where a bio-waste material can be used to produce ZnO-NP directly on cotton at low temperatures and short treatment times without the addition of chemicals and enables the production of cellulosic fabrics with excellent UV protection.

Graphitic Carbon Nitride as a New Sustainable Photocatalyst for Textile Functionalization.

As a promising organic semiconducting material, polymeric graphitic carbon nitride (g-C3N4) has attracted much attention due to its excellent optical and photoelectrochemical properties, thermal stability, chemical inertness, nontoxicity, abundance, and low cost. Its advantageous visible light-induced photocatalytic activity has already been beneficially used in the fields of environmental remediation, biological applications, healthcare, energy conversion and storage, and fuel production. Despite the recognized potential of g-C3N4, there is still a knowledge gap in the application of g-C3N4 in the field of textiles, with no published reviews on the g-C3N4-functionalization of textile materials. Therefore, this review article aims to provide a critical overview of recent advances in the surface and bulk modification of textile fibres by g-C3N4 and its composites to tailor photocatalytic self-cleaning, antibacterial, and flame retardant properties as well as to create a textile catalytic platform for water disinfection, the removal of various organic pollutants from water, and selective organic transformations. This paper highlights the possibilities of producing g-C3N4-functionalized textile substrates and suggests some future prospects for this research area.

Influence of the Prepolymer Type and Synthesis Parameters on Self-Healing Anticorrosion Properties of Composite Coatings Containing Isophorone Diisocyanate-Loaded Polyurethane Microcapsules.

Self-healing anticorrosion composite coatings containing isophorone diisocyanate-loaded polyurethane microcapsules were developed, and comprehensive research on prepolymer and microcapsules synthesis, as well as functional composite coatings preparation and characterization, was performed. The influence of the prepolymer type and the concentration of the stabilizing agent used in the synthesis procedure on the properties of the microcapsules was studied in detail. For this purpose, three different prepolymers were prepared from toluene-2,4-diisocyanate (TDI) and either glycerol, 1,4-butanediol, or 1,6-hexanediol, and their chemical properties were investigated. Microcapsules were synthesized from the obtained prepolymers, according to the oil-in-water polymerization method, where 1,6-hexanediol was used as a chain extender, while the concentration of the stabilizing agent in the synthesis procedure was varied. Microcapsules prepared from TDI-glycerol prepolymer, synthesized in the presence of 10 wt% of the stabilizing agent, showed superior chemical, morphological, and thermo-gravimetrical properties; thus, they were incorporated into the coating in the concentration of 20 wt%. The prepared composite coatings demonstrated self-healing and anticorrosion properties, and thus the developed microcapsules show great potential for the incorporation into the composite anticorrosion coatings at critical points where damage can easily occur, providing longer and more efficient anticorrosion protection.

Bio-Based Epoxy Adhesives with Lignin-Based Aromatic Monophenols Replacing Bisphenol A.

A bio-epoxy surface adhesive for adherence of the metal component species to glass substrate with desirable adhesion strength, converted controlled removal upon request, and bio-based resource inclusion was developed. For the development of resin, three different lignin-based aromatic monophenols, guaiacol, cresol, and vanillin, were used in the chemical epoxidation reaction with epichlorohydrin. The forming transformation process was studied by viscoelasticity, in situ FTIR monitoring, and Raman. Unlike other hydroxyl phenyls, guaiacol showed successful epoxide production, and stability at room temperature. Optimization of epoxide synthesis was conducted by varying NaOH concentration or reaction time. The obtained product was characterized by nuclear magnetic resonance and viscosity measurements. For the production of adhesive, environmentally problematic bisphenol A (BPA) epoxy was partially substituted with the environmentally acceptable, optimized guaiacol-based epoxy at 20, 50, and 80 wt.%. Mechanics, rheological properties, and the possibility of adhered phase de-application were assessed on the bio-substitutes and compared to commercially available polyepoxides or polyurethanes. Considering our aim, the sample composed of 80 wt.% bio-based epoxy/20 wt.% BPA thermoset was demonstrated to be the most suitable among those analyzed, as it was characterized by low BPA, desired boundary area and recoverability using a 10 wt.% acetic acid solution under ultrasound.

New Insights into Antibacterial and Antifungal Properties, Cytotoxicity and Aquatic Ecotoxicity of Flame Retardant PA6/DOPO-Derivative Nanocomposite Textile Fibers.

The aim of this study was to evaluate the antibacterial and antifungal activity, cytotoxicity, leaching, and ecotoxicity of novel flame retardant polyamide 6 (PA6) textile fibers developed by our research group. The textile fibers were produced by the incorporation of flame-retardant bridged 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) derivative (PHED) in the PA6 matrix during the in situ polymerization process at concentrations equal to 10 and 15 wt% (PA6/10PHED and PA6/15PHED, respectively). Whilst the nanodispersed PHED provided highly efficient flame retardancy, its biological activity led to excellent antibacterial activity against Escherichia coli and Staphylococcus aureus, as well as excellent antifungal activity against Aspergillus niger and Candida albicans. The results confirmed leaching of the PHED, but the tested leachates did not cause any measurable toxic effect to the duckweed Lemna minor. The in vitro cytotoxicity of the leached PHED from the PA6/15PHED sample was confirmed for human cells from adipose tissue in direct and prolonged contact. The targeted biological activity of the organophosphinate flame retardant could be beneficial for the development of PA6 textile materials with multifunctional properties and the low ecotoxicity profile, while the PHED's leaching and cytotoxicity limit their application involving the washing processes and direct contact with the skin.