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Abstract There is a wide demand for new biodegradable materials with innovations to improve the basic functions of traditional food packaging and prolong the shelf life of food, enhancing its security and sensorial properties. Poly(L-lactic acid) (PLLA) is a biodegradable biopolymer used in traditional packaging of food because of its non-toxicity, biodegradability, biocompatibility and transparency. The aim of this work is to modify PLLA films in order to prepare an improved material for food active packaging. For this, PLLA was internally blended with zinc oxide (ZnO) nanoparticles and, it was also superficially modified by the deposition of chitosan (CHI) and β-cyclodextrins (β-CD) by layer-by-layer (LbL). These prepared multilayers were characterized by confocal fluorescence microscopy, contact angle measurements, transmission electron microscopy and UV-Vis spectroscopy. On one hand, the proposed multiple modification inhibits polymer-bacterial interactions and improves the biological properties of the PLLA due to the bactericide effect of ZnO nanoparticles and the contact killing capacity of chitosan. On the other hand, the release of the carvacrol incorporated in β-CDs improves the antibacterial and antioxidant properties of prepared films (more than 95 wt% of totally released carvacrol was released within 14 days). This investigation demonstrates that here specifically modified PLLA films could be promising materials in the new trends of biodegradable and active food packaging. Graphical abstract Image 1 Highlights • Biodegradable PLLA was modified to be applied as active packaging. • Multilayers of chitosan and anionic β-cyclodextrin were successfully formed onto PLLA. • Prepared multilayers were effective for the loading and release of carvacrol. [ABSTRACT FROM AUTHOR]

Highlights • HA/CHI multilayers were formed onto smoothen and micropatterned Ti-6Al−4 V alloys. • Hydrophobic micro-patterned surfaces become hydrophilic after HA/CHI deposition. • Multilayers were able to release TRI within the initial period of bacterial adhesion. Abstract Bacterial contamination is a critical problem in medical implants, which are preferential sites for bacterial adhesion, leading to infections which can compromise health and immune system of patients. Commercial titanium alloys are the most commonly used materials for permanent implants in contact with bone, and the prevention of infections on their surface is therefore a crucial challenge for orthopaedic and dental surgeons. Thus, the aim of this work is to develop polysaccharide antibacterial coatings onto modified titanium surfaces with different surface topography, in order to act as reservoirs of antibacterial agents. For this, hyaluronic acid/chitosan polyelectrolyte multilayers were successfully developed after acid hydrolysis of Ti-6Al −4 V alloys. Surface modification could be monitorized by XPS spectroscopy, fluorescence confocal microscopy and contact angle measurements. Furthermore, the effect of surface micropatterning on the stability, hydrophilicity, capability to the loading and release of triclosan and the antibacterial properties of prepared multilayers against Staphylococcus aureus were also analysed. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Multilayers of hyaluronic acid and chitosan were carried out onto PET films. • Multilayers resulted substrates for loading and release of antibacterial agents. • Polysaccharide coating led to the inhibition of bacteria attachment. • Antibacterial agents release along the time was modulated by selective layer loading. Abstract Antibacterial coatings have been widely explored to inhibit biofilm formation in order to prevent post-implantation infections of biomedical devices. However, due to the complex mechanism of bacterial adhesion and proliferation, only the combination of different strategies can lead to higher antibacterial efficiency, especially in the initial stages. For this, layer by layer (LbL) assembly of hyaluronic acid (HA) and chitosan (CHI) was successfully developed onto activated surface of polyethylene terephthalate in order to obtain polyelectrolyte multilayers (PEMs) that combine adhesion resistance, contact killing properties and modulated releasing of antibacterial agents. PEMs showed high efficiency for loading of triclosan (TRI) and rifampicin (RIF). The release of these bactericides could be modulated by their sequential incorporation along the polysaccharide layers. HA/CHI multilayers inhibited E. coli adhesion onto developed surfaces and when TRI and RIF were loaded in the coatings, better antibacterial activity was demonstrated. The possibility of acting as antibacterial reservoir added to the antibacterial properties of the polysaccharide layer make these multilayers promising materials as implants substrates. [ABSTRACT FROM AUTHOR]

Among biomedical community, great efforts have been realized to develop antibacterial coatings that avoid implant-associated infections. To date, conventional mono-functional antibacterial strategies have not been effective enough for successful long-term implantations. Consequently, researchers have recently focused their attention on novel bifunctional or multifunctional antibacterial coatings, in which two or more antibacterial mechanisms interact synergistically. Thus, in this work different chitosan-based (CHI) hydrogel coatings were created on Ti6Al4V surface using genipin (Ti-CHIGP) and polyethylene glycol (Ti-CHIPEG) crosslinking agents. Hydrogel coatings demonstrated an exceptional in vivo biocompatibility plus a remarkable ability to promote cell proliferation and differentiation. Lastly, hydrogel coatings demonstrated an outstanding bacteria-repelling (17–28 % of S. aureus and 33–43 % of E. coli repelled) and contact killing (186–222 % of S. aureus and 72–83 % of E. coli damaged) ability. Such bifunctional antibacterial activity could be further improved by the controlled release of drugs resulting in powerful multifunctional antibacterial coatings. • CHI hydrogel coatings were developed to achieve long-term implantable biomaterials. • Hydrogel coatings exhibited a bifunctional antibacterial activity (repel + kill). • Drug loaded hydrogel coatings synergistically combine three antibacterial mechanisms. [ABSTRACT FROM AUTHOR]

Today, the treatment of implant-associated infections with conventional mono-functional antibacterial coatings has not been effective enough for a prosperous long-term implantation. Therefore, biomedical industry is making considerable efforts on the development of novel antibacterial coatings with a combination of more than one antibacterial strategies that interact synergistically to reinforce each other. Therefore, in this work hyaluronic acid-based (HA) hydrogel coatings were created on the surface Ti6Al4V biomaterial with 1,4-butanediol diglycidyl ether (Ti-HABDDE) and divinyl sulfone (Ti-HADVS) crosslinking agents. Hydrogel coatings displayed an extraordinary in vivo biocompatibility, a remarkable ability to promote cell proliferation, differentiation and mineralization, and capability to sustainedly release drugs. Finally, HA-based hydrogel coatings demonstrated an outstanding multifunctional antibacterial activity: bacteria-repelling (51–55 % of S. aureus and 27–40 % of E. coli), bacteria-killing (82–119 % of S. aureus and 83–87 % of E. coli) and bactericide release killing (drug-loaded hydrogel coatings, R > 2). [Display omitted] [ABSTRACT FROM AUTHOR]

Antibiotics represent one increasingly harmful type of contaminant of emerging concern in treated and non-treated water. They cause the generation of antibiotic-multiresistant organisms, one of the major challenges in current medicine. Plasmonic-photocatalysis using solar energy represents a promising solution for their removal with low energy consumption. Its successful application requires the improvement of photocatalysts' efficiency under sunlight and the development of robust, durable, and efficient substrates for photocatalysts immobilisation. In this work, hybrid TiO 2 :Au nanostars were initially synthesised. Then, two porous membranes were prepared to support this nanocatalyst based on poly (vinylidenefluoride- co -hexafluoropropylene) polymer. Doctor blade and salt leaching casting methods, combined with temperature-induced phase separation, were used to generate membranes with high porosity, 80–90%, which was maintained after nanoparticle incorporation (3, 8 and 10 wt%). The photocatalytic activity of the nanocomposite membranes was tested through the degradation of the antibiotic ciprofloxacin under UV and visible radiation. Salt-leaching membranes containing 10 wt% nanoparticles presented the highest degradation efficiencies, 45% under UV and 35% under visible radiation. In contrast, doctor blade membranes showed 36% and 32% degradation efficiencies, respectively. The reusability of the membranes was assessed in repeated cycles, presenting an average efficiency loss of only 2% after three uses. Finally, the reusability of these membranes was also tested in treated effluent water matrixes, presenting similar, or even better, degradation efficiencies, and a minimum reusability efficiency lost 0–1%. The results demonstrate that these membranes are a promising alternative for the degradation of a wide variety of contaminants under sunlight radiation. [Display omitted] • Synthesised TiO 2 :Au nanostars enhance sunlight absorption at visible wavelengths. • High control on polyvinylidene fluoride porous membrane morphologies. • Efficient degradation of ciprofloxacin under UV and visible radiation. • Membranes with 10 wt% of nanoparticles maintained efficiency after many uses. • Reusable membranes were fully functional in real water effluents. [ABSTRACT FROM AUTHOR]

• Influence of PEDOT:PSS ratio in inks for screen printing sensors has been study. • Reducing PSS content hinders dispersion stability and therefore film conductivity. • Green surfactants have been used satisfactorily to replace Triton™ X-100. • First time reported enzymeless H 2 O 2 sensor with PEDOT:PSS as the unique active part. • Valuable sensitivities have been achieved by PEDOT:PSS sensors for H 2 O 2 detection. Correct levels of hydrogen peroxide in human body are of utmost importance to a variety of physiological functions. Its determination provides valuable information about specific changes that may affect our health. Here we report on PEDOT:PSS electrodes, screen printed on flexible substrates, for the amperometric detection of hydrogen peroxide at -1 V vs Ag/Ag+. PEDOT:PSS-based inks were prepared with different PEDOT-to-PSS ratios and various additives to improve viscosity, adhesion and electrical properties of the printed films. PEDOT:PSS electrodes could detect hydrogen peroxide in the range 1-100 µM with limits of detection ca. 0.97 µM, limits of quantification ca. 1.07 µM and high sensitivities up to 1.7 A·M-1·cm-2 for the best performance electrode. This work represents a relevant contribution towards non-enzymatic detection of hydrogen peroxide with an electrode fabricated using a low-cost printing process. [Display omitted] [ABSTRACT FROM AUTHOR]

The present work is a first approach in order to achieve thermo-sensitive and waterproof polyurethane fibers useful in the textile industry. For this, two polyurethane formulations with glass transition temperatures (T g) close to the body temperature have been synthetized and characterized by several techniques such as Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Dynamic-Mechanical Analysis (DMA) and Thermo-mechanical analysis (TMA). In this manner their thermal and shape memory behavior were determined. It was also estimated the water vapor transmission rate of both polyurethane films. Then, integration of two different microencapsulated phase change materials (PCMs), one with organic shell and another one, with an inorganic shell, was carried out by extrusion in order to achieve materials with thermo-regulating properties. Fibers for both polyurethanes, pristine or loaded with microencapsulated PCMs, were again characterized to check that the thermal and shape memory properties are maintained, and to study their capability to storage and release energy. The promising results pave the way for a new generation of thermo-regulating materials useful in numerous applications such as the textile sector. • Thermo-regulating and waterproof textiles from shape memory polyurethanes (SMPUs). • Shape memory polyurethanes fibers loaded with microencapsulated phase-change materials (MEPCMs). • Phase-change materials (MEPCMs) are capable to store and release energy in a specific temperature range. • New generation of thermo-regulating materials useful in numerous applications such as the textile sector. [ABSTRACT FROM AUTHOR]

Today, Ti6Al4V alloy is the most used and manufactured metallic implantable biomaterial in biomedical industry. However, in recent years it has demonstrated that Ti6Al4V based biomaterials could induce harmful diseases to human health in long-term implantations. Thus, biomedical community makes great efforts in order to improve the biocompatibility of Ti6Al4V implants and to afford additional antibacterial properties. For this, one promising strategy is the activation of Ti6Al4V surface through simple and industrially scalable physicochemical techniques that involve the increase of the thickness of the surface oxidation (TiO 2) and the creation of active hydroxyl groups (Ti-OH). In this work, Ti6Al4V biomaterials were activated with chemical wet (CWT), electrochemical (ET), and physical oxygen plasma (POPT) treatments. Their surface activation effectiveness was evaluated in terms of surface damage, changes in surface roughness, wettability, and oxidation and hydroxylation capability (Ti-OH/TiO 2 ratio). So, results show that acidic HCl:H 2 O 2 piranha CWT of Ti6Al4V surfaces is the most effective surface activation procedure with improved surface reactivity (highest Ti-OH/TiO 2 ratio), cytocompatibility, cell proliferation, and hemocompatibility. Antibiofilm activity of pristine Ti6Al4V was also enhanced by acidic HCl:H 2 O 2 piranha treatment, leading to a decrease in bacterial adhesion of 30 % against S. aureus and E. coli. • Ti6Al4V surface was activated using chemical wet (CWT), electrochemical (ET), and physical oxygen plasma (POPT) treatments. • CWTs activated more effectively Ti6Al4V surface displaying a roughness close to nano-scale plus an increased wettability. • CWTs significantly improved cytocompatibility, cell proliferation and hemocompatibility of pristine Ti6Al4V. • Ti6Al4V activated with CWT repelled S. aureus and E. coli bacteria strains endowing antibiofilm properties in 30 %. [ABSTRACT FROM AUTHOR]

[Display omitted] • The ECL response of screen-printed graphite electrodes is explained. • Carbon paste composition determines electrode wettability and electron transfer rates. • The ECL response of laser-induced HOPG SPE depends mainly on the paste binder. • ECL is highly sensitive to electrode microstructure and surface chemistry. • Image analysis of ECL using a smartphone facilitates the study of electrode activity. Screen printed graphite electrodes are widely used in electroanalysis, and increasingly in electrochemiluminescence (ECL) applications. However, their response is very dependent on graphite paste composition and electrode fabrication processes. This work studies the ECL of the tris(2,2′-bipyridyl)ruthenium (II)/tripropylamine (Ru(bpy) 3 2+/TPrA) system at four graphite electrodes printed from three commonly found graphite pastes. Dropsens graphite electrodes are included in the study for completeness. Electrodes were also treated with a CO 2 laser in air (7.7–12.0 mJ cm−2) to remove surface binder impurities to form laser-induced-HOPG, a much more electrochemically active form of graphite. It has been found that the ECL intensity expressed by graphite electrodes depends on electrode kinetics but also very significantly on electrode wettability, both of which depend on paste composition, particularly carbon mix and polymer binder. The observed differences between as-printed and laser-activated electrodes were investigated using a combination of ECL generation techniques, scanning electron microscopy (SEM), contact angle measurements, thermal analysis and X-ray photoelectron spectroscopy (XPS). An affordable method to assess electrode quality using ECL and image capture with a mobile phone camera and open-source image analysis software is presented. [ABSTRACT FROM AUTHOR]

Commercial screen-printed carbon electrodes have been treated with a CO 2 laser energy of 12.8 mJ cm−2 in air. This thermal treatment resulted in an increase in the crystallinity of the graphite and an enhancement in electron transfer rates, determined by Raman spectroscopy and cyclic voltammetry, respectively. Laser treatment also facilitated the introduction of oxygen groups by anodization at a potential of 1.55 V vs Ag, which was highly beneficial for the simultaneous detection of dopamine (DA), even in the presence of ascorbic acid (AA), and uric acid (UA) by differential pulse voltammetry (DPV). Anodized laser-treated electrodes were much better at resolving the oxidation peaks of these three substances compared to the as-received commercial electrodes. A linear response from 0.34 to 1.6 µM and a detection limit of 80 nM were obtained for DA in the presence of 20 µM uric acid and 160 µM ascorbic acid. This work demonstrates a suitable method to improve sensitivity in carbon-based printable sensors for the simultaneous analysis of oxygen surface-sensitive substances. [ABSTRACT FROM AUTHOR]

Hyaluronic acid (HA) solutions were crosslinked with divinyl sulfone (DVS) and subsequently loaded with antibiotic molecules to obtain biocompatible and antibacterial injectable hydrogels. The crosslinking degree of the hydrogels was modulated by varying the reaction time and the HA:DVS weight ratio. Synthesized HA-DVS hydrogels were characterized by their rheological properties, pore size, swelling capacity and hydrolytic and thermal degradation. Biocompatibility was assessed by measuring pH, osmolality and by in vitro cytotoxic assay. Acetyl salicylic (AAS) loaded hydrogels display anti-inflammatory properties in vitro , whereas cefuroxime (CFX), tetracycline (TCN) and amoxicillin (AMX) loaded hydrogels show in vitro antibacterial activity against Staphylococcus aureus. The combine use of antibiotics and AAS produces a synergic effect that reduces the S. aureus population up to a log10 reduction (R) of 5.55. Overall results show that antibiotic/AAS loaded HA-DVS hydrogels could be effectively used to combat S. aureus infections and to increase the antibacterial activity of antibiotics commonly used against S. aureus. [Display omitted] • Biocompatible HA-DVS injectable hydrogels were obtained after hydrogel formulations optimization. • A sustained release of CFX, TCN and AMX antibiotics, and AAS anti-inflammatory agent, from different HA-DVS formulations was achieved. • Hydrogels loaded with a combination of antibiotics and AAS demonstrated a synergic enhanced antibacterial activity against S. aureus. [ABSTRACT FROM AUTHOR]

Biodegradable, non-toxic and transparent poly (l-lactic acid) (PLLA) biopolymer is modified in order to obtain an improved material with antibacterial properties for its use as active packaging of food. For this, PLLA films were endowed with the bactericidal effect of ZnO nanoparticles by internal blending and the bacteria contact-killing properties of the biopolymer chitosan (CHI) by superficial modification. Surface functionalization with CHI was carried out by covalent or electrostatic functionalization which were comparatively analyzed in terms of yield and stability. Additionally, the effect of employed CHI concentration and molecular weight was also studied for both modification methods. Modified films were characterized by confocal fluorescence microscopy, contact angle measurements, UV–Vis spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy and electrostatic force microscopy. The antibacterial properties of each modification on PLLA were studied against Escherichia coli, showing the greater microbial death after covalent functionalization with CHI. Moreover, stability of modified films was studied in enzymatic and non-enzymatic medium and it was improved by chemical crosslinking with the natural molecule genipin. The valuable properties of PLLA, as well as the derived antibacterial properties of the incorporation of ZnO nanoparticles and CHI, make prepared films highly attractive candidates for the innovative packaging industry. Image 1 • Biodegradable PLLA was modified to be improved as antibacterial packaging material. • CHI was linked on PLLA films blended with ZnO by covalent and electrostatic interactions. • The stability of covalent CHI linkage was enhanced by crosslinking with genipin. [ABSTRACT FROM AUTHOR]

• Hyaluronic acid and chitosan assembled as hydrogels and nanometric multilayers. • Formation of the complexes was demonstrated in hydrogels and multilayers. • HA/CHI hydrogels and multilayers showed self-healing properties in a few minutes. • Self-healed hydrogels maintained the rheological properties of the initial material. In this work, polyelectrolyte complexes (PEC) were obtained in form of nanometric polyelectrolyte multilayers (PEMs) and macroscopic hydrogels by electrostatic interactions between two natural polysaccharides: hyaluronic acid (HA) and chitosan (CHI). PEM was developed onto poly(ethylene terephthalate) (PET) surface by layer-by-layer approach. The characterization of both systems was carried out simultaneously by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), X ray diffraction (XRD), thermogravimetric analysis (TGA) and transmission and scanning electronic microscopy (TEM and SEM). The rheological properties of PEC hydrogels were also analysed. The formation of the complexes was demonstrated due to electrostatic interactions, which in turn resulted being responsible for intrinsic self-healing ability. This is a highly demanded property in reducing replacements costs. Both, PEC hydrogels and multilayers showed self-healing properties within few minutes, this fact proves the versatility of HA/CHI complexes to easily obtain different forms of self-healable materials interesting as functional biomedical supports and coatings. [ABSTRACT FROM AUTHOR]

Cytotoxicity is a critical parameter for materials intended for biological applications, such as food packaging. Shape-memory polyurethanes (SMPUs) have garnered significant interest due to their versatile properties and adaptability in synthesis. However, their suitability for biological applications is limited by the use of aromatic isocyanates, such as methylene diphenyl 4,4'-diisocyanate (MDI) and toluene diisocyanate (TDI), which are commonly used in SMPU synthesis but can generate carcinogenic compounds upon degradation. In this study, thermo-responsive shape-memory polyurethanes (SMPUs) were synthesized using poly(tetramethylene ether) glycol (PTMG) and castor oil (CO) as a chain extender with four different isocyanates-aromatic (MDI and TDI), aliphatic (hexamethylene diisocyanate [HDI] and isophorone diisocyanate [IPDI])-to evaluate their impact on polyurethane cytotoxicity. Cytotoxicity assays were conducted on the synthesized SMPU samples before and after exposure to light-induced degradation. The results showed that prior to degradation, all samples exhibited cell proliferation rates above 90%. However, after degradation, the SMPUs containing aromatic isocyanates demonstrated a drastic reduction in cell proliferation to values below 10%, whereas the samples with aliphatic isocyanates maintained cell proliferation above 70%. Subsequently, the influence of polyol chain length was assessed using PTMG, with molecular weights of 1000, 650, and 250 g·mol -1 . The results indicated that the SMPUs with longer chain lengths exhibited higher cell proliferation rates both before and after degradation. The thermal and mechanical properties of the SMPUs were further characterized using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermomechanical analysis (TMA), providing comprehensive insights into the behavior of these materials.

Electrochemiluminescence (ECL) is typically confined to a micrometric region from the electrode surface. This study demonstrates that ECL emission can extend up to several millimeters away from the electrode employing electrogenerated chlorine bubbles. The mechanism behind this bubble-enhanced ECL was investigated using an Au microelectrode in chloride-containing and chloride-free electrolyte solutions. We discovered that ECL emission at the gas/solution interface is driven by two parallel effects. First, the bubble corona effect facilitates the generation of hydroxyl radicals capable of oxidizing luminol while the bubble is attached to the surface. Second, hypochlorite generated from chlorine sustains luminol emission for over 200 s and extends the emission range up to 5 mm into the solution, following bubble detachment. The new approach can increase the emission intensity of luminol-based assays 5-fold compared to the conventional method. This is demonstrated through a glucose bioassay, using a midrange mobile phone camera for detection. These findings significantly expand the potential applications of ECL by extending its effective range in time and space.

The copper-free azide-alkyne click reaction has shown to be a successful alternative to immobilize covalently a fluorescente compound onto poly(-l-lactic) acid (PLLA) surfaces. Proceded by basic hydrolysis and amidation reaction, typical surface characterization techniques have validated each functionaliztion step and the success of the conjugation. This method offers a catalyst-free option for various surface conjugations, extremely demanded in biomedical and biosensory fields., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Screen printing is one of the most used techniques for developing printed electronics. It stands out for its simplicity, scalability, and effectivity. Specifically, the manufacturing of hybrid integrated circuits has promoted the development of the technique, and the photovoltaic industry has enhanced the printing process by developing high-performance metallization pastes and high-end screens. In recent years, fine lines of 50 μm or smaller are about to be adopted in mass production, and screen printing has to compete with digital printing techniques such as inkjet printing, which can reach narrower lines. In this sense, this work is focused on testing the printing resolution of a high-performance stainless-steel screen with commercial conductive inks and functional lab-made inks based on reduced graphene oxide using an interdigitated structure. We achieved electrically conductive functional patterns with a minimum printing resolution of 40 μm for all inks., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Photocuring of chitosan has shown great promise in the extrusion-based 3D printing of scaffolds for advanced biomedical and tissue engineering applications. However, the poor mechanical stability of methacrylated chitosan photocuring ink restricts its applicability. The inclusion of co-networks by means of simultaneous polycomplex formation is an effective method by which to solve this drawback, but the formed hydrogel inks are not printable. This work aims to develop new photocurable chitosan inks based on the simultaneous photocrosslinking of methacrylated chitosan (CHIMe) with N,N'-methylenebisacrylamide, polyethylene glycol diacrylate, and acrylic acid to be applied in extrusion 3D printing. Interestingly, the polycomplex co-network corresponding to the acrylic-acid-based ink could be successfully printed by the here-presented simultaneous photocuring strategy. Further, the conversion of photocrosslinking was studied via photo-DSC analyses that revealed a clear dependence on the chemical structure of the employed crosslinking agents (from 40 to ~100%). In addition, the mechanical and rheological properties of the photocured hydrogels were comparatively studied, as well as the printing quality of the extruded scaffolds. The newly developed chitosan photocurable inks demonstrated extrusion printability (squareness ~0.90; uniformity factor ~0.95) and tunable mechanical properties (Young modulus 14-1068 Pa) by means of different crosslinking approaches according to the chemical architecture of the reactive molecules employed. This work shows the great potential of photocrosslinkable chitosan inks.

Self-standing nanocomposite films were prepared by three-dimensional UV-induced radical copolymerization of methacrylated alginate (MALG) with acrylic acid (AA) and reinforced with graphene oxide (GO) to improve both mechanical strength and dye adsorption capacity in wastewater decontamination operations. Dynamic mechanical-thermal analysis revealed variations in storage modulus: the higher the GO content, the higher the storage modulus (E') values. Also, the higher the temperature (associated with a lower and lower water content of films), the larger values of E' for the films of the same composition (E'(25 °C) = 676.6-1538.7 MPa; E'(100 °C) = 886.9-2066.6 MPa), providing insights into the compatibility between GO and the MALG/AA matrix, as well as, assessing the improvement in the nanocomposite's final mechanical properties. These crosslinked films in a dry state exhibited rapid water uptake and relatively short drying times (ca. 30 min at room temperature for the MALG/AA/GO composites) resulting from the swelling-drying studies and water contact angle measurements. The efficacy of methylene blue removal from water assessed via UV-VIS spectrometry revealed excellent results, expressed as an adsorption yield of 70-80% and 85-98% after 30 h and 258 h, respectively, of immersion time of films into an MB aqueous solution of 12.5 mg/L (as the contaminated water model). The reusability of the same films was evaluated by consecutive extraction processes of MB from the composite membranes when the content of desorbed dye was also spectrophotometrically monitored and conducted in acidic conditions (HCl aqueous solutions of pH 2). Overall, the introduction of GO in the developed self-standing MALG/AA nanocomposite films exhibited enhanced mechanical properties and increased efficiency for dye removal applications. Their great reutilization potential was highlighted by low drying times and a good ability to release the dye initially adsorbed. Thus, the prepared films could be suitable materials for sustainable and effective water treatment technologies.

The aim of this work is the design and 3D printing of a new electrochemical sensor for the detection of Listeria monocytogenes based on loop mediated isothermal amplification (LAMP). The food related diseases involve a serious health issue all over the world. Listeria monocytogenes is one of the major problems of contaminated food, this pathogen causes a disease called listeriosis with a high rate of hospitalization and mortality. Having a fast, sensitive and specific detection method for food quality control is a must in the food industry to avoid the presence of this pathogen in the food chain (raw materials, facilities and products). A point-of-care biosensor based in LAMP and electrochemical detection is one of the best options to detect the bacteria on site and in a very short period of time. With the numerical analysis of different geometries and flow rates during sample injection in order to avoid bubbles, an optimized design of the microfluidic biosensor chamber was selected for 3D-printing and experimental analysis. For the electrochemical detection, a novel custom gold concentric-3-electrode consisting in a working electrode, reference electrode and a counter electrode was designed and placed in the bottom of the chamber. The LAMP reaction was optimized specifically for a primers set with a limit of detection of 1.25 pg of genomic DNA per reaction and 100% specific for detecting all 12 Listeria monocytogenes serotypes and no other Listeria species or food-related bacteria. The methylene blue redox-active molecule was tested as the electrochemical transducer and shown to be compatible with the LAMP reaction and very clearly distinguished negative from positive food samples when the reaction is measured at the end-point inside the biosensor., Competing Interests: The authors declare no competing interests., (© 2023 The Authors.)

Great efforts have been performed on the production of advanced biomaterials with the combination of self-healing and wound healing properties in implant/tissue engineering biomedical area. Inspired by this idea, chitosan (CHI) based hydrogels can be used to treat a less investigated class of harmful chronic wounds: ulcers or pressure ulcers. Thus, CHI was crosslinked with previously synthesized polyethylene glycol diacid (PEG-diacid) to obtain different CHI-PEG hydrogel formulations with high H-bonding tendency resulting in self-repair ability. Here presented results show biocompatible, antibacterial, anti-inflammatory, and self-healing CHI-PEG hydrogels with a promising future in the treatment of ulcerated wounds by a significant improvement in metabolic activity (94.51 ± 4.38 %), collagen and elastin quantities (2.12 ± 0.63 μg collagen and 4.97 ± 0.61 μg elastin per mg dermal tissue) and histological analysis. Furthermore, cefuroxime (CFX), tetracycline (TCN) and amoxicillin (AMX) antibiotics, and acetylsalicylic acid (ASA) anti-inflammatory agent were sustainedly released for enhancing antibacterial and anti-inflammatory activities of hydrogels., (Copyright © 2022 Elsevier B.V. All rights reserved.)

In situ-forming, biodegradable, and self-healing hydrogels, which maintain their integrity after damage, owing to dynamic interactions, are essential biomaterials for bioapplications, such as tissue engineering and drug delivery. This work aims to develop in situ, biodegradable and self-healable hydrogels based on dynamic covalent bonds between N-succinyl chitosan (S-CHI) and oxidized aldehyde hyaluronic acid (A-HA). A robust effect of the molar ratio of both S-CHI and A-HA was observed on the swelling, mechanical stability, rheological properties and biodegradation kinetics of these hydrogels, being the stoichiometric ratio that which leads to the lowest swelling factor (×12), highest compression modulus (1.1·10−3 MPa), and slowest degradation (9 days). Besides, a rapid (3 s) self-repairing ability was demonstrated in the macro scale as well as by rheology and mechanical tests. Finally, the potential of these biomaterials was evidenced by cytotoxicity essay (>85%).