Bio-based epoxy resin/carbon nanotube coatings applied on cotton fabrics for smart wearable systems.

Electroactive coatings for smart wearable textiles based on a furan bio-epoxy monomer (BOMF) crosslinked with isophorone diamine (IPD) and additivated with carbon nanotubes (CNTs) are reported herein. The effect of BOMF/IPD molar ratio on the curing reaction, as well as on the properties of the crosslinked resins was first assessed, and it was found that 1.5:1 BOMF/IPD molar ratio provided higher heat of reaction, glass transition temperature, and mechanical performance. The resin was then modified with CNT to prepare electrically conductive nanocomposite films, which exhibited conductivity values increased by eight orders of magnitude upon addition of 5 phr of CNTs. The epoxy/CNT nanocomposites were finally applied as coatings onto a cotton fabric to develop electrically conductive, hydrophobic and breathable textiles. Notably, the integration of CNTs imparted efficient and reversible electrothermal behavior to the cotton fabric, showcasing its potential application in smart and comfortable wearable electronic devices.

Thermophilic biocatalysts for one-step conversion of citrus waste into lactic acid.

Agri-food residues offer significant potential as a raw material for the production of L-lactic acid through microbial fermentation. Weizmannia coagulans, previously known as Bacillus coagulans, is a spore-forming, lactic acid-producing, gram-positive, with known probiotic and prebiotic properties. This study aimed to evaluate the feasibility of utilizing untreated citrus waste as a sustainable feedstock for the production of L-lactic acid in a one-step process, by using the strain W. coagulans MA-13. By employing a thermophilic enzymatic cocktail (Cellic CTec2) in conjunction with the hydrolytic capabilities of MA-13, biomass degradation was enhanced by up to 62%. Moreover, batch and fed-batch fermentation experiments demonstrated the complete fermentation of glucose into L-lactic acid, achieving a concentration of up to 44.8 g/L. These results point to MA-13 as a microbial cell factory for one-step production of L-lactic acid, by combining cost-effective saccharification with MA-13 fermentative performance, on agri-food wastes. Moreover, the potential of this approach for sustainable valorization of agricultural waste streams is successfully proven. KEY POINTS: • Valorization of citrus waste, an abundant residue in Mediterranean countries. • Sustainable production of the L-( +)-lactic acid in one-step process. • Enzymatic pretreatment is a valuable alternative to the use of chemical.

Characterization of polyethylene terephthalate (PET) and polyamide (PA) true-to-life nanoplastics and their biological interactions.

Plastic and microplastics, including polyethylene (PE), polypropylene (PP), and polystyrene (PS), are major contributors to environmental pollution. However, there is a growing recognition of the need to investigate a wider range of plastic polymers to fully understand the extent and impacts of plastic pollution. This study focuses on the comprehensive characterization of true-to-life nanoplastics (T2LNPs) derived from polyethylene terephthalate (PET) and polyamide (PA) to enhance our understanding of environmental nanoplastics pollution. T2LNPs were produced through cryogenic mechanical fragmentation of everyday items made from these polymers. A solid methodological framework incorporating various characterization techniques was established. Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and thermogravimetric analysis (TGA) were employed to study the chemical composition and confirm the absence of chemical modifications possibly occurring during fragmentation. Atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to analyze the morphology of the T2LNPs. Additionally, AFM image analysis compared to dynamic light scattering (DLS) measurements provided insights into the size distribution and the stability of the T2LNP suspensions. The results revealed the heterogeneity of T2LNPs derived from PET and PA, emphasizing the importance of studying different plastic compositions to comprehensively understand nanoplastics pollution. Lastly, the distinctive characteristics and morphology of T2LNPs were translated into the realm of biological interactions, offering initial insights into the influence of these disparities on the formation of the protein corona on the surface of T2LNPs. By proposing T2LNPs as test materials and establishing a comprehensive characterization approach, this study aims to bridge the knowledge gap regarding the behavior and toxicity of nanoplastics. Furthermore, it highlights the need for a reliable and transferable analytical package for nanoplastic characterization to facilitate future studies on the environmental impact of nanoplastics.

Preparation and properties of novel binary and ternary highly amorphous poly(vinyl alcohol)-based composites with hybrid nanofillers.

Smart protective coatings and devices are currently of great interest. In particular, they can absorb or reflect harmful waves of electromagnetic interference (EMI). In this work, novel binary and ternary composites with highly amorphous poly(vinyl alcohol) (HAVOH) as a matrix and single-walled carbon nanotubes (SWCNTs) and MXenes as nanofillers were prepared. HAVOH is a recently patented kind of poly(vinyl alcohol) (PVOH) that was modified with diol monomers. MXenes are a new type of inorganic two-dimensional (2D) nanoparticle consisting of carbides, nitrides and carbonitrides. Three series of composites, HAVOH/SWCNTs, HAVOH/MXenes and HAVOH/SWCNTs/MXenes, were prepared using the solvent casting method. Samples were tested with various methods to study their structure, electrical properties, thermal behavior and EMI-shielding properties. HAVOH/3.0 wt.% SWCNTs/3.0 wt.% MXene specimens revealed a shielding effectiveness of 55 dB, which is 122 times better than that of the neat matrix. These results are promising for the fabrication of films with protective effects against EMI.

Cellulose Isolation from Tomato Pomace: Part II-Integrating High-Pressure Homogenization in a Cascade Hydrolysis Process for the Recovery of Nanostructured Cellulose and Bioactive Molecules.

This work proposes a biorefinery approach for utilizing tomato pomace (TP) through a top-down deconstructing strategy, combining mild chemical hydrolysis with high-pressure homogenization (HPH). The objective of the study is to isolate cellulose pulp using different combinations of chemical and physical processes: (i) direct HPH treatment of the raw material, (ii) HPH treatment following acid hydrolysis, and (iii) HPH treatment following alkaline hydrolysis. The results demonstrate that these isolation routes enable the production of cellulose with tailored morphological properties from TP with higher yields (up to +21% when HPH was applied before hydrolysis and approximately +6% when applied after acid or after alkaline hydrolysis). Additionally, the side streams generated by this cascade process show a four-fold increase in phenolic compounds when HPH is integrated after acid hydrolysis compared to untreated sample, and they also contain nanoparticles composed of hemicellulose and lignin, as shown by FT-IR and SEM. Notably, the further application of HPH treatment enables the production of nanostructured cellulose from cellulose pulp derived from TP, offering tunable properties. This approach presents a sustainable pathway for the extraction of cellulose and nanocellulose, as well as the valorization of value-added compounds found in residual biomass in the form of side streams.

Direct Laser Writing of Chitosan-Borax Composites: Toward Sustainable Electrochemical Sensors.

In this study, the laser-induced graphitization process of sustainable chitosan-based formulations was investigated. In particular, optimal lasing conditions were investigated alongside the effect of borax concentration in the chitosan matrix. In all cases, it was found that the obtained formulations were graphitizable with a CO2 laser. This process gave rise to the formation of high surface area, porous, and electrically conductive laser-induced graphene (LIG) structures. It was found that borax, as a cross-linker of chitosan, enabled the graphitization process when its content was ≥30 wt % in the chitosan matrix, allowing the formation of an LIG phase with a significant content of graphite-like structures. The graphitization process was investigated by thermogravimetric analysis (TGA), Raman, X-ray photoemission (XPS), and Fourier transform infrared (FTIR) spectroscopies. LIG electrodes obtained from CS/40B formulations displayed a sheet resistance as low as 110 Ω/sq. Electrochemical characterization was performed after a 10 min electrode activation by cycling in 1 M KCl. A heterogeneous electron transfer rate, k0, of 4 × 10-3 cm s-1 was determined, indicating rapid electron transfer rates at the electrode surface. These results show promise for the introduction of a new class of sustainable composites for LIG electrochemical sensing platforms.

All natural mussel-inspired bioadhesives from soy proteins and plant derived polyphenols with marked water-resistance and favourable antibacterial profile for wound treatment applications.

HYPOTHESIS: Implementation of tissue adhesives from natural sources endowed with good mechanical properties and underwater resistance still represents a challenging research goal. Inspired by the extraordinary wet adhesion properties of mussel byssus proteins resulting from interaction of catechol and amino residues, hydrogels from soy protein isolate (SPI) and selected polyphenols i.e. caffeic acid (CA), chlorogenic acid (CGA) and gallic acid (GA) under mild aerial oxidative conditions were prepared. EXPERIMENTS: The hydrogels were subjected to chemical assays, ATR FT-IR and EPR spectroscopy, rheological and morphological SEM analysis. Mechanical tests were carried out on hydrogels prepared by inclusion of agarose. Biological tests included evaluation of the antibacterial and wound healing activity, and hemocompatibility. FINDINGS: The decrease of free NH2 and SH groups of SPI, the EPR features, the good cohesive strength and excellent underwater resistance (15 days for SPI/GA) under conditions relevant to their use as surgical glues indicated an efficient interaction of the polyphenols with the protein in the hydrogels. The polyphenols greatly also improved the mechanical properties of the SPI/ agarose/polyphenols hydrogels. These latter proved biocompatible, hemocompatible, not harmful to skin, displayed durable adhesiveness and good water-vapour permeability. Excellent antibacterial properties and in some cases (SPI/CGA) a favourable wound healing activity on dermal fibroblasts was obtained.

Effectiveness of Mesoporous Silica Nanoparticles Functionalized with Benzoyl Chloride in pH-Responsive Anticorrosion Polymer Coatings.

Smart polymer coatings embedding stimuli-responsive corrosion inhibitor nanocarriers are commonly exploited, in the literature, for the development of high-performance active coatings. In this work, high-surface-area amino-functionalized mesoporous silica nanoparticles (MSN-NH2) were developed with a one-step synthesis process and then functionalized with benzoyl chloride (MSN-BC) through a reaction with amino groups. MSN-BC are able to release benzoic acid (BA) in acid and alkaline conditions as a result of the hydrolysis of the pH-sensitive amide bond. MSN-BC were embedded in polymer coatings to exploit the pH-dependent release of corrosion-inhibiting BA. After an in-depth characterization of the developed functional nanoparticles and of their pH-dependent release kinetics of BA, MSN-BC were embedded in an acrylic matrix, realizing coatings for the corrosion protection of aluminum AA2024 alloys. Results demonstrate the effectiveness of the nanoparticles' porous structure for a high loading of the anticorrosive active agent BA and the long-lasting efficiency of the coating for the corrosion protection of aluminum alloys, as validated by morphological and electrochemical impedance spectroscopy (EIS) measurements. EIS experiments were carried out with up to 21 days of exposure to a corrosive environment, revealing the potentialities of the acrylic coatings embedding MSN-BC for the protection of aluminum alloys.

Poly(lactic acid)/Plasticizer/Nano-Silica Ternary Systems: Properties Evolution and Effects on Degradation Rate.

Plasticized nanocomposites based on poly(lactic acid) have been prepared by melt mixing following a two-step approach, adding two different oligomeric esters of lactic acid (OLAs) as plasticizers and fumed silica nanoparticles. The nanocomposites maintained a remarkable elongation at break in the presence of the nanoparticles, with no strong effects on modulus and strength. Measuring thermo-mechanical properties as a function of aging time revealed a progressive deterioration of properties, with the buildup of phase separation, related to the nature of the plasticizer. Materials containing hydroxyl-terminated OLA showed a higher stability of properties upon aging. On the contrary, a synergistic effect of the acid-terminated plasticizer and silica nanoparticles was pointed out, inducing an accelerated hydrolytic degradation of PLA: materials at high silica content exhibited a marked brittleness and a dramatic decrease of molecular weight after 16 weeks of aging.

Monitoring Water Absorption and Desorption in Untreated and Consolidated Tuff by a Non-Invasive Graphene-Based Humidity Sensor.

A hybrid montmorillonite (MMT)/reduced graphene oxide (rGO) film was realised and used as a non-invasive sensor for the monitoring of water absorption and desorption in pristine and consolidated tuff stones. This film was obtained by casting from a water dispersion containing graphene oxide (GO), montmorillonite and ascorbic acid; then the GO component was thermo-chemically reduced and the ascorbic acid phase was removed by washing. The hybrid film showed electrical surface conductivity that varied linearly with the relative humidity, ranging from 2.3 × 10-3 S in dry conditions to 5.0 × 10-3 S at 100% RH. The sensor was applied onto tuff stone samples through the use of a high amorphous polyvinyl alcohol layer (HAVOH) adhesive, which guaranteed good water diffusion from the stone to the film and was tested during water capillary absorption and drying tests. Results show that the sensor is able to monitor water content changes in the stone, being potentially useful to evaluate the water absorption and desorption behaviour of porous samples both in laboratory environments and in situ.

Sustainable and Green Production of Nanostructured Cellulose by a 2-Step Mechano-Enzymatic Process.

Nanostructured cellulose (NC) represents an emerging sustainable biomaterial for diverse biotechnological applications; however, its production requires hazardous chemicals that render the process ecologically unfriendly. Using commercial plant-derived cellulose, an innovative strategy for NC production based on the combination of mechanical and enzymatic approaches was proposed as a sustainable alternative to conventional chemical procedures. After ball milling, the average length of the fibers was reduced by one order of magnitude (down to 10-20 µm) and the crystallinity index decreased from 0.54 to 0.07-0.18. Moreover, a 60 min ball milling pre-treatment followed by 3 h Cellic Ctec2 enzymatic hydrolysis led to NC production (15% yield). Analysis of the structural features of NC obtained by the mechano-enzymatic process revealed that the diameters of the obtained cellulose fibrils and particles were in the range of 200-500 nm and approximately 50 nm, respectively. Interestingly, the film-forming property on polyethylene (coating ≅ 2 µm thickness) was successfully demonstrated and a significant reduction (18%) of the oxygen transmission rate was obtained. Altogether, these findings demonstrated that nanostructured cellulose could be successfully produced using a novel, cheap, and rapid 2-step physico-enzymatic process that provides a potential green and sustainable route that could be exploitable in future biorefineries.

Massive foreign body reaction and osteolysis following primary anterior cruciate ligament reconstruction with the ligament augmentation and reconstruction system (LARS): a case report with histopathological and physicochemical analysis.

BACKGROUND: Autologous hamstrings and patellar tendon have historically been considered the gold standard grafts for anterior cruciate ligament reconstruction (ACLR). In the last decades, the utilization of synthetic grafts has re-emerged due to advantageous lack of donor site morbidity and more rapid return to sport. The Ligament Augmentation and Reconstruction System (LARS) has demonstrated to be a valid and safe option for ACLR in the short term. However, recent studies have pointed out the notable frequency of associated complications, including synovitis, mechanical failure, and even chondrolysis requiring joint replacement. CASE PRESENTATION: We report the case of a 23-year-old male who developed a serious foreign body reaction with wide osteolysis of both femoral and tibial tunnels following ACLR with LARS. During first-stage arthroscopy, we performed a debridement of the pseudocystic mass incorporating the anterior cruciate ligament (ACL) and extending towards the tunnels, which were filled with autologous anterior iliac crest bone graft chips. Histological analysis revealed the presence of chronic inflammation, fibrosis, and foreign body giant cells with synthetic fiber inclusions. Furthermore, physicochemical analysis showed signs of fiber depolymerization, increased crystallinity and formation of lipid peroxidation-derived aldehydes, which indicate mechanical aging and instability of the graft. After 8 months, revision surgery was performed and ACL revision surgery with autologous hamstrings was successfully carried out. CONCLUSIONS: The use of the LARS grafts for ACLR should be cautiously contemplated considering the high risk of complications and early failure.

A versatile approach to evaluate the occurrence of microfibers in mussels Mytilus galloprovincialis.

Microplastics of fibrous shape are esteemed to be the most abundant micro-debris form present in the environment. Despite the occurrence of microfibers in fish may pose a risk to human health, the literature is scarce regarding studies on the contamination in commercial marine fish mostly due to methodological issues. In this study, a versatile approach, able to discriminate among natural and synthetic microfibers according to the evaluation of specific morphological features, is proposed in farmed mussels (Mytilus galloprovincialis). The approach was useful to determine that microfibers were present in 74% of mussel samples, with a mean number of 14.57 microfibers/individual, corresponding to 3.13 microfibers/g w.w. A negative correlation between the size of analysed mussels and the amount of microfibers/g w.w. was detected, showing that smaller specimens contained more microfibers than the larger ones. This work paves the way to further studies aimed to adequately assess the risk that microfibers may pose to marine biota, also considering the commercial value as seafood items of many species of the Mytilus genus and the potential implication for human exposure.

Instant in situ formation of a polymer film at the water-oil interface.

The water-oil interface is an environment that is often found in many contexts of the natural sciences and technological arenas. This interface has always been considered a special environment as it is rich in different phenomena, thus stimulating numerous studies aimed at understanding the abundance of physico-chemical problems that occur there. The intense research activity and the intriguing results that emerged from these investigations have inspired scientists to consider the water-oil interface even as a suitable setting for bottom-up nanofabrication processes, such as molecular self-assembly, or fabrication of nanofilms or nano-devices. On the other hand, biphasic liquid separation is a key enabling technology in many applications, including water treatment for environmental problems. Here we show for the first time an instant nanofabrication strategy of a thin film of biopolymer at the water-oil interface. The polymer film is fabricated in situ, simply by injecting a drop of polymer solution at the interface. Furthermore, we demonstrate that with an appropriate multiple drop delivery it is also possible to quickly produce a large area film (up to 150 cm2). The film inherently separates the two liquids, thus forming a separation layer between them and remains stable at the interface for a long time. Furthermore, we demonstrate the fabrication with different oils, thus suggesting potential exploitation in different fields (e.g. food, pollution, biotechnology). We believe that the new strategy fabrication could inspire different uses and promote applications among the many scenarios already explored or to be studied in the future at this special interface environment.

NIR-Absorbing Mesoporous Silica-Coated Copper Sulphide Nanostructures for Light-to-Thermal Energy Conversion.

Plasmonic nanostructures, featuring near infrared (NIR)-absorption, are rising as efficient nanosystems for in vitro photothermal (PT) studies and in vivo PT treatment of cancer diseases. Among the different materials, new plasmonic nanostructures based on Cu2-xS nanocrystals (NCs) are emerging as valuable alternatives to Au nanorods, nanostars and nanoshells, largely exploited as NIR absorbing nanoheaters. Even though Cu2-xS plasmonic properties are not linked to geometry, the role played by their size, shape and surface chemistry is expected to be fundamental for an efficient PT process. Here, Cu2-xS NCs coated with a hydrophilic mesoporous silica shell (MSS) are synthesized by solution-phase strategies, tuning the core geometry, MSS thickness and texture. Besides their loading capability, the silica shell has been widely reported to provide a more robust plasmonic core protection than organic molecular/polymeric coatings, and improved heat flow from the NC to the environment due to a reduced interfacial thermal resistance and direct electron-phonon coupling through the interface. Systematic structural and morphological analysis of the core-shell nanoparticles and an in-depth thermoplasmonic characterization by using a pump beam 808 nm laser, are carried out. The results suggest that large triangular nanoplates (NPLs) coated by a few tens of nanometers thick MSS, show good photostability under laser light irradiation and provide a temperature increase above 38 °C and a 20% PT efficiency upon short irradiation time (60 s) at 6 W/cm2 power density.

Non-covalent small molecule partnership for redox-active films: Beyond polydopamine technology.

HYPOTHESIS: The possibility to use hexamethylenediamine (HMDA) to impart film forming ability to natural polymers including eumelanins and plant polyphenols endowed with biological activity and functional properties has been recently explored with the aim to broaden the potential of polydopamine (PDA)-based films overcoming their inherent limitations. 5,6-dihydroxyindole-2-carboxylic acid, its methyl ester (MeDHICA) and eumelanins thereof were shown to exhibit potent reducing activity. EXPERIMENTS: MeDHICA and HMDA were reacted in aqueous buffer, pH 9.0 in the presence of different substrates to assess the film forming ability. The effect of different reaction parameters (pH, diamine chain length) on film formation was investigated. Voltammetric and AFM /SEM methods were applied for analysis of the film redox activity and morphology. HPLC, MALDI-MS and 1HNMR were used for chemical characterization. The film reducing activity was evaluated in comparison with PDA by chemical assays and using UV stressed human immortalized keratinocytes (HaCat) cells model. FINDINGS: Regular and homogeneous yellowish films were obtained with moderately hydrophobic properties. Film deposition was optimal at pH 9, and specifically induced by HMDA. The film consisted of HMDA and monomeric MeDHICA accompanied by dimers/small oligomers, but no detectable MeDHICA/HMDA covalent conjugation products. Spontaneous assembly of self-organized networks held together mainly by electrostatic interactions of MeDHICA in the anion form and HMDA as the dication is proposed as film deposition mechanism. The film displayed potent reducing properties and exerted significant protective effects from oxidative stress on HaCaT.

Sustainable Cellulose-Aluminum-Plastic Composites from Beverage Cartons Scraps and Recycled Polyethylene.

The sustainable management of multilayer paper/plastic waste is a technological challenge due to its composite nature. In this paper, a mechanical recycling approach for multilayer cartons (MC) is reported, illustrating the realization of thermoplastic composites based on recycled polyethylene and an amount of milled MC ranging from 20 to 90 wt%. The effect of composition of the composites on the morphology and on thermal, mechanical, and water absorption behavior was investigated and rationalized, demonstrating that above 80 wt% of MC, the fibrous nature of the filler dominates the overall properties of the materials. A maleated polyethylene was also used as a coupling agent and its effectiveness in improving mechanical parameters of composites up to 60 wt% of MC was highlighted.

Washing load influences the microplastic release from polyester fabrics by affecting wettability and mechanical stress.

Microplastics released from textiles during the washing process represent the most prevalent type of microparticles found in different environmental compartments and ecosystems around the world. Release of microfibres during the washing process of synthetic textiles is due to the mechanical and chemical stresses that clothes undergo in washing machines. Several washing process parameters, conditions, formulations of laundering additives have been correlated to microfibre release and some of them have been identified to affect microfibre release during washing process, while no correlation has been evaluated between microfibre release and washing load. In the present study, microfibre release was evaluated as function of the washing load in a real washing process, indicating a progressive decrease of microfibre release with increasing washing load. The quantity of released microfibres increased by around 5 times by decreasing the washing load due to a synergistic effect between water-volume to fabric ratio and mechanical stress during washing. Moreover, the higher mechanical stress to which the fabric is subjected in the case of a low washing load, hinders the discrimination of the effect on the release of other washing parameters like the type of detergent and laundry additives used.

Innovative Silver-Based Capping System for Mesoporous Silica Nanocarriers Able to Exploit a Twofold Anticorrosive Mechanism in Composite Polymer Coatings: Tailoring Benzotriazole Release and Capturing Chloride Ions.

In this work, engineered stimuli-responsive mesoporous silica nanoparticles (MSNs) were developed and exploited in polymer coatings as multifunctional carriers of a typical corrosion inhibitor, benzotriazole (BTA). In detail, a new capping system based on a BTA-silver coordination complex, able to dissolve in acid and alkaline conditions and to simultaneously tailor the BTA release and the capture of chloride ions, was properly designed and realized. Acrylic coatings embedding the engineered MSNs were deposited onto iron rebar samples and tested for their protective capability in acid and alkaline environments. Results highlighted the high potential of the proposed system for the protection of metals, due to the synergistic effect of the mesoporous structure and the capping system, which guaranteed both the sequestration of chloride ions and the on-demand release of the effective amount of anticorrosive agents able to ensure the enhanced protection of the substrate.

Comparison of biodegradable polyesters degradation behavior in sand.

Sandy beaches represent environmental compartments particularly vulnerable to litter pollution, and they reflect the magnitude of pollution of adjacent compartments: water and coastal areas. The substitution of conventional polymers by biodegradable materials is generally considered as an alternative for reducing environmental accumulation of plastic debris. The present study is aimed to investigate the degradation of poly(lactic acid), poly(ε-caprolactone), poly(butylenesuccinate adipate) and poly(3-hydroxybutyrate) buried in sand for 267 days, simulating them as beach litter. The analysed polyesters showed different degradation mechanisms and kinetics. PLA is mainly subjected to weathering by physical aging; after an initial faster degradation of the amorphous phase, PCL showed a decrease of its degradation rate; similarly to PCL, the degradation of PBSA started from the amorphous phase; PHB is clearly subjected to biological degradation. The degradation trend of the investigated materials in sand decreased in the order PHB > PBSA > PCL > PLA. PLA, PCL and PBSA did not undergo complete degradation in sand during the testing time.