Due to the increasing environmental pollution caused by synthetic plastics, particularly in Mexico, there has been growing interest in the development of sustainable materials derived from biopolymers and agri-food waste. This research evaluated the use of eggshell nanoparticles (ENPs), which are rich in calcium carbonate, as functional reinforcements in various polymeric matrices. ENPs were obtained through high-energy milling for periods of 1–3 h, reaching an average size of 84 ± 40 nm after 2 h, with 91 % of the particles < 100 nm. These nanoparticles were incorporated at concentrations of 1–3 wt.% into gellan gum (GG) films intended for the manufacture of compostable utensils and were also blended with polylactic acid (PLA) to produce filaments processed by extrusion. Additionally, superhydrophobic coatings inspired by the lotus leaf effect were developed by applying ENP and ZnO micro- and nanoparticles onto glass substrates. The materials were characterized using optical, confocal, and electron microscopy, as well as FTIR, XRD, and texture image analysis. The results for the films showed that the incorporation of 3 % ENPs into GG significantly improved their mechanical, thermal, and hydrophobic properties; in the filaments, it was observed that 2 % ENP supports flexibility. On the other hand, the coatings with the highest surface roughness were those in which ENP was used with ZnO nanoparticles with contact angles > 150°, confirming its superhydrophobic character. Overall, these results demonstrate that the use of waste materials such as eggshells enables the development of biodegradable materials with enhanced functional properties and potential applications in packaging, utensils, and surface treatments, contributing to a circular economy and reducing the environmental impact of conventional plastics.

Introduction

The transition to a circular bioeconomy requires valorizing organic waste into high-value bioproducts. We studied marine bacteria and renewable carbon from lignocellulosic biomass to produce polyhydroxyalkanoates (PHA), biodegradable bioplastics. Two marine bacteria were selected: Cobetia marina (culture collection) and Roseibium alexandrii, isolated from a PHA biofilm after long-term marine exposure.

Methods

Over 50 isolates were screened for PHA accumulation using phaC gene detection and Nile red fluorescence. R. alexandrii was chosen for its consistent activity, with C. marina as reference. Both were grown on simple carbon sources (glucose, crotonic acid, gamma-valerolactone [GVL]) and complex sugars from organosolv-hydrolyzed cellulose. Different C/N ratios of 12.5, 25, and 50 were tested to assess nutrient balance effects. After 48 h, cell dry weight and Nile red fluorescence were measured, and PHA was extracted and analyzed by NMR spectroscopy.

Results

Overall, C/N 12.5 yielded the highest biomass and fluorescence in most conditions, especially with glucose, crotonic acid, and birch- or cellulose-derived fractions. C/N 25 showed moderate results, while 50 led to reduced growth and PHA synthesis. GVL alone was a poor substrate, but when present in low amounts within sugar mixtures, it did not interfere, enabling the direct use of spontaneously separated crude hydrolysates. Some of the sugar-rich fractions enabled biomass and PHA yields comparable or superior to glucose. Crotonic acid, a PHA degradation product, supported high PHA yields, suggesting a promising route to re-synthesize PHA from its own breakdown products.

Conclusions

These results highlight the potential of marine microbes and unrefined waste streams in circular, scalable bioplastic production. The present communication will discuss how these advances contribute to the development of novel, sustainable polymeric materials and open new pathways for integrating microbial biotechnology into polymer science.

Acknowledgments: Project TED2021-130211B-C31 funded by MCIN/AEI /10.13039/501100011033 and by the European Union NextGenerationEU/ PRTR

The use of resins derived from epoxidized soybean oil (ESO) promotes advances in sustainable materials and reduces carbon footprint. There is technological potential for the development of nanocomposites with viable technical performance, aligning functional properties with environmental impact mitigation. However, ESO acts as an electrical insulator, limiting applications as a material for static charge dissipation and electromagnetic interference shielding. Therefore, electrical and hybrid nanocomposites based on ESO were prepared with fumaric acid as the curing agent, using carbon nanotubes (MWCNT) and graphene (G) as conductive nanofillers. The ESO/MWCNT/G nanocomposites were evaluated through electrical conductivity (σ), electromagnetic interference shielding (EMI SE), and reflection loss (RL), adopting hybridization between MWCNT/G with 5/0, 4/1, 3/2, 2/3, 1/4, and 0/5 parts per hundred resin (phr). The pure ESO exhibited insulating behavior, with a conductivity of 1.61 x 10⁻¹¹ S/cm, which resulted in low electromagnetic shielding performance (~1 dB) between 8.2-18 GHz. The ESO nanocomposite with MWCNT/G (5/0 phr) showed the highest electrical conductivity value of 5.81 x 10⁻⁵ S/cm, leading to the highest magnetic shielding performance between 12-15 dB. Among the hybrid nanocomposites, the MWCNT/G (3/2 phr) formulation demonstrated synergy in magnetic shielding effectiveness, although still lower than that of MWCNT/G (5/0 phr). The shielding mechanism of the ESO/MWCNT/G nanocomposites was primarily due to reflection, except for MWCNT/G (5/0 phr), which, in the Ku band, showed nearly identical values of energy shielded by reflection and absorption. In terms of RL, the best results were observed for MWCNT/G (3/2 and 2/3 phr) in the Ku band, reaching -10 dB (corresponding to 90% attenuation), which is the minimum standard value for a material with good absorptivity. The results suggest potential for application as a coating for static charge dissipation.

Introduction

Perovskia atriplicifolia Benth.is an ornamental plant with a strong, pleasant scent, belonging to the family Lamiaceae. In traditional medicine, it has been used to prevent and cure various skin diseases. In this study, the chemical components and antioxidant activity of P. atriplicifolia extract were analyzed and a rheological and textural characterization of the extract-based hydrogel was performed.

Methods

Spectrophotometric and HPLC methods were used to determine the phytochemical components and the antioxidant activity of P. atriplicifolia herb extract.

The rheological properties of the extract-based hydrogel were determined using a rotational rheometry method in a plate-to-plate arrangement at 25 °C. The hydrogel was also analyzed using a TX-700 texture analyzer, in the Compression/Relaxation/Tension (CRT) and Texture Profile Analysis (TPA) modes.

Results

The total contents of polyphenols, flavonoids, phenolic acids, and condensed tannins in the extract were 64.46 mg/mL, 17.39 mg/mL, 4.92 mg/mL, and 4.12 mg/mL, respectively. Among phenolic compounds, hesperidin (0.16 mg/mL), caffeic (0.04 mg/mL), and rosmarinic (1.32 mg/mL) acid are identified. Additionally, it was found that the course of the flow curves was non-linear. In the range of shear rates tested, the apparent viscosity decreased, indicating that the formulations are non-Newtonian fluids, diluted by shear force. The results of the CRT and TPA tests showed that the hydrogel had high adhesiveness, supporting effective skin retention and bioadhesiveness. It also exhibited high elasticity (1.32), indicating good flexibility in regaining its shape, and cohesiveness above 1, confirming strong structural integrity and good skin adherence.

Conclusions

A hydrogel based on P. atriplicifolia extract containing compounds with antioxidant activity has beneficial rheological and textural properties, ensuring optimal application of the preparation on the skin.

Introduction

Chitosan (CS) materials are biodegradable, biocompatible, and can exhibit antimicrobial, hemostatic, and antioxidant properties [1].

Functionalization of chitosan with quaternary ammonium groups (QCS) is beneficial for improving its properties, such as its mucoadhesiveness and bioadhesiveness, and its antimicrobial, anticoagulant, antioxidant, and immunomodulatory properties, making chitosan more suitable for tissue engineering and transdermal drug delivery [2-3].

Methods

CS/QCS binary fibers were prepared by electrospinning using poly(ethyleneoxide) as a co-spinning agent, followed by its selective removal from the mats.

The composition, morphology, and properties of CS/QCS fibers were investigated, and biocompatible fibers with an optimal CS/QCS ratio that led to a progressive biodegradation rate were investigated in wound healing experiments.

Results

The presence of the two biopolymers in binary fibers, CS and QCS, was confirmed by FTIR and ¹H-NMR spectroscopy.

Enzymatic degradation, monitored in lysozyme solution in PBS (pH=7.4) for 7 days, showed an increase in the rate of biodegradation along with increasing QCS content.

The presence of QCS in the fibers endowed them with strong antimicrobial activity, especially against Gram-negative bacteria.

Tests on normal human fibroblasts have shown that the fibers can be safely used as medical devices.

Subcutaneous implantation of fibers in Wistar rats did not affect biochemical parameters, indicating their potential for safe in vivo use.

CS/QCS fibers in wound healing experiments proved that there was total closure and active healing of second-/third-degree burn wounds in rats.

Conclusion

All these findings indicate their potential to function as effective bioresorbable dressings.

[1] Z. Guo; R. Xing, S. Jiu, Z. Zhong, X. Ji, L. Wang; P. Li, Carbohydr Res , 342(10) (2007) 1329–1332.

[2] S. Guo, Y. Ren, R. Chang, Y. He, D. Zhang, F. Guan, M. Yao, ACS Appl Mater Interfaces 14 (2022) 34455–34469

[3] B.-I. Andreica, X. Cheng, L. Marin, Eur Polym J 139 (2020) 110016

Acknowledgments: H2020-MSCA-RISE-2019: SmartWoundMonitoringRestorativeDressings (SWORD) (no. 873123)

In this study, we investigate the formation of electrostatically self-assembled multilayer films (MLFs) of the anionic xanthan gum (XG) and the cationic diethylaminoethyl dextran (DD) polysaccharides. XG/DD MLFs are formed on a gold (Au) surface by implementing the layer-by-layer (LbL) method. The MLFs are comprised of 10 alternating single layers (5 double layers) of the two oppositely charged polysaccharides. The constructed MLFs are studied by using the surface plasmon resonance (SPR) and the quartz crystal microbalance with dissipation (QCM-D) methods. The reported adsorbed masses Γ of the layers are within the range of 8-14 mg/m². Bovine serum albumin (BSA) showcases satisfactory adsorption and interaction with the MLFs both in neutral and acidic environments with increment Γ values of ~3 mg/m², while porcine gastric mucin (PGM) exhibits similar behavior in neutral environments. The XG/DD MLFs show decent stability against the increase of ionic strength and the rinsing with water between successive biopolymer deposition cycles. MLFs with adsorbed BSA and PGM show minimal mass losses due to pH changes and increased ionic strength, respectively. In general, the XG/DD MLFs are considered as promising options for use in drug delivery systems, wound-healing scaffolds, and biosensors, as well as for combating microbial growth due to the charges of the uncomplexed segments of the polysaccharides.

Introduction:
Nature has long been a source of inspiration for material scientists, offering intricate designs and multifunctional properties. In recent years, biomimetic nanofibers have emerged as a promising class of materials for applications in healthcare, environmental sensing, and soft robotics. However, the limitations of conventional polymers in mimicking dynamic biological behavior have driven the search for next-generation materials that can adapt, respond, and evolve under varying stimuli.

Methods:
This study explores the literature about a novel family of stimuli-responsive copolymers synthesized through controlled radical polymerization, incorporating dynamic covalent cross-links and supramolecular motifs. Electrospinning techniques were employed to fabricate ultrafine fibers, simulating extracellular matrix architectures. A suite of characterization methods, including scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA), were used to assess structural fidelity, thermal behavior, and viscoelastic performance.

Results:
Relevant literature points out that the developed nanofibers exhibit significant responsiveness to pH, temperature, and ionic strength, enabling reversible shape transformations and tunable mechanical properties. Notably, fibers embedded with thermoresponsive domains demonstrate up to 60% contraction at mild physiological temperatures (37–42°C), while pH-sensitive segments showed self-healing capabilities under acidic conditions. Comparative analysis revealed a threefold increase in adaptability compared to conventional electrospun scaffolds.

Conclusions:
The integration of intelligent polymer architectures into nanofibrous formats paves the way for highly adaptive materials that closely emulate natural tissue behavior. These findings suggest strong potential for applications in regenerative medicine, wearable electronics, and responsive filtration systems. Future works are expected explore in vivo biocompatibility and long-term stability to advance toward translational applications.

Biopolymers have emerged as sustainable alternatives to conventional plastics, showing advantages like biocompatibility, biodegradability, and non-toxicity [1]. Nevertheless, their aging processes under service life conditions still need a deeper evaluation [2], [3]. This study examined films of three commercial compositions for rigid/flexible packaging based on poly (lactic acid) (PLA)/poly (butylene adipate-co-terephthalate) (PBAT) blends under oxidative degradation conditions.

Commercial PLA/PBAT films, of 100 µm thickness, were exposed to short- (0 - 2 h) and long-term ozone aging (24 - 96 h) in an Anseros SIM 6050 T chamber at 40 ^oC and 300 pphm of ozone concentration. Analytical characterisation included measurements for surface hydrophilicity (WCA), microscopic morphology (SEM), chemical structure (FTIR-ATR), thermal properties (DSC), and mechanical performance.

Ozonation caused significant variations in surface properties after long-term ozone treatment, demonstrated by a constant decrease in WCA. A 96 h treatment led to abiotic degradation revealed by chemical structure analysis, where carbonyl and carboxyl indices were reduced by 17% and 16%, indicating degradation of oxidised functional groups and products, along with mild chain scission. Surface morphology showed surface changes with initial oxidation, reinforcement and re-degradation tendencies. These changes were limited to surface modifications, as slight bulk changes were reported in thermal properties. Mechanical performance improved, with the aging factor increasing from 0.5 to 0.9 to 1.14 - 1.30, suggesting that structural stability was maintained. Phase distribution within the polymer matrix influenced the extent of abiotic degradation. The progressive increase in additives such as plasticisers and inorganic fillers likely buffered the effects of ozone treatment.

Short- and long-term treatments promoted oxidative degradation of biodegradable film surfaces. Only long-term exposure led to macroscopic surface damage, altering morphology, chemical structure, and hydrophilicity, without affecting deeper layers, while maintaining thermal properties and slightly enhancing mechanical performance.

ACKNOWLEDGEMENTS

Authors acknowledge funding from the Agència Valenciana de la Innovació (AVI) through the INNEST/2022/295 project.

To address environmental concerns in the food packaging industry, there is a growing demand for biodegradable materials with enhanced functional properties. Poly(lactic acid) (PLA) is a promising biodegradable polymer for food packaging, yet it exhibits limitations in barrier performance, mechanical strength, and antibacterial activity. This study focuses on enhancing PLA films by incorporating activated carbon (AC) derived from grape pomace (GP), an abundant byproduct of wine production, thereby promoting a sustainable and circular bioeconomy approach. Biochar (BC) was produced via pyrolysis of GP at 350, 450, 550, and 650 °C for 1 and 2 hours. The optimal BC (obtained at 550 °C for 1 hour) exhibited a porous morphology suitable for further activation. ACs were then synthesized from both raw GP and BC at 450 °C and 550 °C for 1 hour. The most effective variants, AC_550_1h and ACBC_550_1h, were selected based on their superior porosity and used to fabricate PLA films at different loadings (1, 2, 3, 4, and 5 wt.%). The films were characterized using FTIR, XRD, SEM, EDS, and optical profilometry, and evaluated for their adsorption capacity (water and ethanol) and mechanical properties. The optimal formulation, PLA_3ACBC, exhibited enhanced elasticity and adsorption capacity, along with the successful formation of surface nanopillars—confirmed via profilometry. These nanopillars significantly improved antibacterial performance against E. coli and S. aureus compared to smooth, unmodified films. The results show that AC addition enhances the sorption and mechanical behavior of PLA films up to a threshold (3 wt.%). Beyond this concentration, particle aggregation and microcrack formation reduce film performance. Films incorporating AC from BC retained their mechanical integrity better at higher loadings than those using AC from raw GP. This study demonstrates a sustainable strategy for valorizing grape pomace into high-performance activated carbon additives for biodegradable food packaging.

Introduction: The accumulation of plastic debris in marine environments poses an ecological threat, particularly in semi-enclosed basins such as the Mediterranean Sea. Biodegradable plastics have emerged as promising alternatives to conventional polymers, yet evaluating their actual degradation performance under environmental conditions remains methodologically challenging. Protocols, standardized and reproducible, fail to account for the complexity of in situ variables—such as temperature, solar radiation, hydrodynamics, and seasonal fluctuations—which can profoundly affect degradation kinetics. This highlights the urgent need for field-based studies that reflect real-world scenarios. Materials and Methods: We conducted a one-year in situ degradation study at the port of Calpe (Spain), exposing polyethylene terephthalate (PET), polybutylene-succinate-co-adipate (PBSA), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and a 70:30 PBSA:PHBV blend, each 200  µm thick. Sampling was performed at 2, 6, 9, and 12 months. We assessed mass loss, biofilm protein concentration, surface morphology, roughness, thermal stability and chemical changes. Results: PHBV showed the highest degradation (41.8% mass loss at 12 months), followed by the 70:30 blend (24.1%) and PBSA (11.2%), while PET remained unchanged. Biofilm’s protein content remained stable for the first 9 months but increased sharply at month 12 across all materials, less markedly in the 70:30 blend. SEM revealed surface damage in all biodegradable polymers, especially PHBV, while PET served as a microbial support. Thermal behavior changes aligned with degradation, whereas FTIR alterations were limited. Surface roughness increased over time in PHBV and the blend, consistent with microbial activity; PBSA showed a more variable pattern, and PET remained unaltered. Conclusion: Our findings confirm the decisive role of polymer composition in driving degradation under natural marine conditions and underscore the need for realistic, long-term field studies to guide the development of truly sustainable plastic alternatives. Acknowledgments: Projects TED2021-130211B-C31 and PID2021-128749OB-C32 were funded by MCIN/AEI /10.13039/501100011033 and by the European Union NextGenerationEU/ PRTR and by MCIN/AEI/10.13039/501100011033 and FEDER “Una manera de hacer Europa”, respectively.