Brain drug delivery poses a significant challenge due to the blood-brain barrier’s extremely reduced permeability to most molecules, making it a considerable obstacle for the effective treatment of neurological and psychiatric diseases. Furthermore, conventional pharmaceutical formulations tend to lead to low drug targeting, leave drugs susceptible to enzymatic and chemical degradation, and do not easily reach high drug strength in liquid and semisolid preparations. To tackle these issues, intranasal nanoemulgels were developed, for direct nose-to-brain drug delivery, and overall improved therapeutic efficacy and safety. Nanoemulgels containing antiepileptic drug molecules phenytoin and fosphenytoin, and nanoemulgels loaded with a repurposed anti-inflammatory drug for brain cancer treatment, were produced through spontaneous emulsification, using a mixture of pre-selected oils, surfactants, co-surfactants, co-solvents and aqueous solutions of a thermosensitive gelling polymer, Poloxamer 407. Formulations were optimized and characterized in what concerned their droplet size, polydispersity index, zeta potential, pH, osmolality, stability, viscosity and rheologic behavior, in vitro drug release, and in vitro therapeutic efficacy and safety. Results showed that low droplet sizes (between 20 and 200 nm) and reduced PDI values (< 0.3) were obtained, as well as high drug strengths. The nanoemulgels depicted a pseudoplastic non-Newtonian rheological behavior, with gelling temperatures adequate for intranasal delivery (bellow the mean nasal temperature, 32 ºC). An overall high controlled cumulative drug release was also obtained (around 80% or higher after 24 hours), and in vitro therapeutic efficacy in glioblastoma cell lines proved that the developed nanoplatforms had improved anticancer effects. Hence, intranasal nanoemulgels with ideal physicochemical characteristics and preliminarily proven therapeutic effects for the treatment of different brain diseases were successfully developed. Assays in in vivo models might further confirm their potential, and their simple and cost-effective production method might catapult these nanocomposites into easing their way to industrial production.

Introduction. 2-Isopropenyl-2-oxazoline (iPOx) is a monomer belonging to the 2-oxazolines class. Unlike typical 2-oxazolines that undergo ring-opening polymerization, iPOx polymerizes via its vinyl group, retaining the 2-oxazoline functionality which offers valuable sites for post-polymerization modifications, especially with carboxylic compunds. Thus, iPOx serves as a versatile building block for the design of functional (co)polymers. Conventional synthesis routes for iPOx often involve harsh conditions, limiting their practicality and scalability. This study explores multiple synthetic routes for the preparation of iPOx, aiming to establish a more accessible and practical method.

Methods. The synthesis followed well-established protocols, starting from methacrylic acid or its derivatives, which are reacted with aminoalcohols or haloalkylamines in various solvents. The resulting hydroxyamides or haloamides were then cyclized to obtain the final product, iPOx.

Results. Several synthetic routes were evaluated for the preparation of iPOx, varying the starting methacrylate derivatives, nucleophiles, and solvents. Reactions using methacrylic anhydride and 2-chloroethylamine yielded the highest purity intermediates, which were efficiently cyclized to iPOx under basic conditions. Hydroxyamide-based routes also produced good yields although they required harsher conditions during the cyclization step. Overall, the optimized pathway demonstrated improved scalability, reduced reaction times, and minimized byproduct formation compared to conventional methods. FTIR and NMR spectroscopy was used for structural confirmation of intermediates.

Conclusions. This study systematically evaluated various synthetic routes for the preparation of iPOx. The influence of the starting materials and reaction conditions on the reaction yield and purity of the final compound was also assessed. The optimized synthesis protocol provided a more practical and scalable route to iPOx, with improved efficiency and reduced byproduct formation.

The urgent need for sustainable solutions in agriculture has prompted the exploration of novel materials to mitigate issues such as excessive fertilizer use, inefficient water management, and soil contamination. Addressing these challenges, this work presents innovative interpenetrated polymeric networks (IPN) based on chitosan (CTS) crosslinked with tris(cyclic carbonate) (TrisCC), engineered as controlled-release biostimulant delivery systems (BDS). The IPN synthesis employed TrisCC, prepared by means of click thiol-ene chemistry, and varying CTS concentrations (2–6% w/v) to modulate network characteristics. A fixed crosslinker-to-CTS ratio targeted 30% amino group involvement, and product properties were thoroughly characterized, including rheology, micromorphology, swelling, biodegradability, and in vitro release of biostimulants, such as melatonin (MEL) or glycine betaine (GB).

The IPN formulated with 6% CTS (CTS₆-TrisCC₃₀) demonstrated optimal mechanical strength and a highly porous architecture, achieving a remarkable swelling index of 4300%. All systems displayed soil biodegradability, with half-life values influenced by the degree of crosslinking and polymer concentration. Sustained, aqueous release profiles for MEL and GB indicated consistent attainment of bioactive concentrations.

These results highlight the considerable promise of CTS-based IPNs as sustainable, controlled‑release platforms for agricultural biostimulants. The innovation lies in the integration of natural biopolymer networks with tunable degradation and release properties, potentially enabling precise nutrient and stress-mitigation strategies in crops. Future work will focus on validating these delivery systems under field conditions to confirm their agronomic efficacy in real‑world environments.

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Poly(lactic acid) (PLA) is a biodegradable, bio-based polymer with promising applications in sustainable materials. However, its inherent brittleness, poor UV resistance, and limited thermal stability hinder broader use in advanced applications such as packaging and biomedical devices. Interface engineering through the incorporation of functional inorganic nanomaterials offers a potential route to overcome these limitations while maintaining the environmental advantages of PLA. In this study, we report on the design, synthesis, and characterization of PLA nanocomposites reinforced with surface-modified graphitic carbon nitride (g-C₃N₄, CN), a metal-free, 2D nanomaterial with unique optical and structural properties. CN was synthesized from melamine and subsequently functionalized using mild acid oxidation and silanization to improve dispersion and compatibility with the PLA matrix. These modifications introduced reactive –OH, –NH, and alkoxysilane groups on the CN surface, enabling hydrogen bonding and covalent interactions with PLA during melt blending. Mechanical testing showed that with only 1 wt% silanized CN, the elongation at break of PLA increased sevenfold, from 6% to 42%, without sacrificing tensile strength. Optical analysis demonstrated a dramatic reduction in UV transmittance below 400 nm, while visible-light transparency remained above 80%. These enhancements were attributed to improved interfacial adhesion and uniform nanofiller dispersion, as confirmed by means of FTIR, TEM, XRD, and XPS. This work demonstrates that interface engineering via surface-functionalized inorganic nanofillers can effectively enhance the mechanical flexibility, UV barrier, and thermal stability of PLA with minimal filler content. Our approach provides a scalable and environmentally conscious strategy for developing multifunctional PLA-based nanocomposites tailored for advanced material applications.

Implementing sustainability and circularity concepts involves the conscious use and treatment of various types of waste to promote the transition from a linear to a circular economy and reduce the carbon footprint. This study explores the use of wood waste that has undergone hydrothermal treatment as a sustainable filler in bioplastics, with the aim of formulating composite biomaterials as an alternative to fossil-based materials. Wood waste was subjected to a sustainable hydrothermal carbonization treatment at a temperature of 210 °C, the limiting temperature to avoid cellulose decomposition. The produced particles were then introduced into the poly(butylene succinate) (PBS) matrix via melt mixing, varying the processing time (2 min and 5 min) and screw rotation speed (20 rpm and 60 rpm), at different weight ratios. For comparison, biocomposites based on PBS and micro-crystalline cellulose have been produced following the same processing protocols.

The obtained composite materials were characterized using thermal (TGA/DTG), calorimetric (DSC), mechanical (tensile and DMTA tests) and rheological (oscillatory tests) analyses. Additionally, the materials were subjected to a degradation process to evaluate their resistance to hydrolytic and photo-oxidative degradation, as well as to burial in soil. All the results obtained highlight that the wood waste particles, subjected to hydrothermal carbonization (HTC), were dispersed uniformly and have a reinforcing action on the bioplastic matrix. The calorimetric analysis suggests a clear nucleating effect of both fillers, leading to a significant increase in the crystalline degree of the PBS matrix. The elastic modulus values of the biocomposites are significantly higher than the value of the neat matrix, and this increase is more pronounced for the materials containing hydrothermally treated particles.

In conclusion, hydrothermally treated wood particles can be considered as a valuable alternative to high-cost conventional micro-crystalline cellulose.

Bone tissue, the second most frequently replaced tissue in the human body, requires over four million surgeries annually, often with considerable risk, driving the advancement of tissue engineering as a promising alternative to autologous grafts through the development of multifunctional, biocompatible, and bioactive 3D scaffolds that promote osteoconductivity and mimic the native bone environment. In this study, poly(lactic acid) (PLA), a bio-based, mechanically strong yet hydrophobic polymer, was blended with poly(vinyl alcohol) (PVA), a biodegradable, hydrophilic polymer with lower mechanical strength, to fabricate composite filaments. Six PLA/PVA ratios were evaluated. Scaffolds were fabricated via Fused Deposition Modeling (FDM) and subsequently freeze-dried to enhance porosity and water absorption. To improve bioactivity, scaffolds were surface-coated with hydroxyapatite (HA), a naturally occurring bone mineral synthesized via a hydrothermal method. Scaffolds were thoroughly characterized through FTIR and XRD (physicochemical analysis), SEM and EDS (morphological analysis), and micro-CT. Their performance under simulated physiological conditions was examined through water absorption and mechanical testing. The freeze-dried scaffold with a 25:75 PLA/PVA ratio showed the highest water absorption capacity of 277.7% after 210 minutes, compared to its non-freeze-dried counterpart, which reached 270.1% in 75 minutes. Compression testing further demonstrated that scaffolds possessed a Young’s modulus of 12.284 MPa, closely approximating that of natural cancellous bone. The synthesized HA for coating had a meso-nanometric average particle size of 32.5 nm and a uniform spherical morphology. Its successful incorporation into the scaffold was confirmed by FTIR, while uniform dispersion across the scaffold surface was verified by SEM imaging. These findings indicate that the freeze-dried PLA/PVA (25:75) scaffold reinforced with hydroxyapatite presents an effective and sustainable approach for bone tissue engineering. Its combination of mechanical strength, high water absorption, and bioactive surface properties makes it a strong candidate for future bone regeneration applications.

Chicken eggshells are an abundant waste from the food industry, composed mainly of calcium carbonate (~96%) along with proteins, and have demonstrated potential as reinforcing agents in biodegradable polymeric matrices. Their rigid mineral structure, biodegradability, and high surface area after milling make them suitable candidates for use in sustainable packaging development. In this study, eggshell powder (ESP) was valorized as inorganic fillers for the development of poly(lactic acid) (PLA) and reprocessed PLA (rPLA) biocomposites plasticized with acetyl tributyl citrate (ATBC). ESP was obtained from post-consumer eggshells by a process involving washing, sterilization, shredding, grinding and sieving to achieve particle sizes below 45 µm. ESP microparticles were incorporated into PLA-rPLA-ATBC matrices at 1, 3 and 5 wt.%, and further processed by melt extrusion (170-190 °C) into filaments for subsequent thermoforming by hot-pressing. The mechanical, morphological and thermal properties of the resulting biocomposites were analyzed. Homogeneous and transparent ESP-loaded films were successfully obtained. The results indicate that increasing the ESP content improves the stiffness of the material, while the addition of ATBC improved processability and the flexibility of the final biocomposites. This work contributes to the circular economy by valorizing agro-industrial waste as functional additives in biodegradable polymers. This first step shows that eggshell particles as mechanical reinforcements and potential carriers of active compounds within matrices, such as active food packaging, are an attractive alternative for the development of next generation sustainable packaging materials.

The mitigation of air pollution caused by fine particulate matter remains an urgent global concern. To address this challenge, sustainably and bio-based air filters incorporating waste-derived natural fillers offer a promising alternative to conventional synthetic materials. In this study, innovative sandwich-structured membranes were developed by integrating a hot-pressed mat of waste wool fibers (WWFs) as a structural core, flanked by two fibrous outer layers composed of polylactic acid (PLA) and finely ground waste wool powder (WWP), produced via the solution blow spinning (SBS) technique. The resulting sandwich-structured waste wool-based membrane (S-WWM) was tested under various flow conditions and environmental humidity levels. The incorporation of 10 wt% WWP into the PLA matrix enhanced the spinnability and fiber morphology due to changes in solution viscosity. The multilayer structure, characterized by a balance between pore size and low packing density, achieved outstanding PM₁ filtration efficiency (99.5%), with a moderate pressure drop (70 Pa) at 32 L/min. In addition, the membrane showed strong performance retention over five filtration cycles and remained stable in humid conditions. These membranes are characterized by the unique properties of wool fibers, such as excellent breathability and mechanical strength, combined with high filtration efficiency achieved by PLA composite fibers. These results demonstrate the potential of upcycled wool-based materials in fabricating high-performance, reusable, and environmentally friendly air filtration systems.

The consideration of sustainability in the plastic industry encompasses three aspects through to reduce the environmental impacts generated: migration from the use of raw fossil polymers to biopolymers from renewable sources, efficient energy consumption and greener options for final waste disposal. Therefore, biocomposites could be an option to generate impact in the three aspects.The use of polilactic acid (PLA) as a polymer matrix has the potential to enable a great number of final disposal options, since PLA is considered biodegradable and compostable, but also to reduce energy consumption in processing and assure the migration to the use of biopolymers. Although this polymer is relatively fragile, this could be interpreted as an opportunity for improvement by using cellulose as a reinforcement agent and a way to utilize by-products such as sawdust, a typical waste that is not currently taken advantage of, to generate valued-added products that have the biodegradable characteristics whilst simultaneously displaying improved mechanical properties. In this study, a biocomposite generated by reactive extrusion, combining PLA, maleic anhydride as the coupling agent, and cellulose isolated from sawdust, is created. The composite's mechanical properties were evaluated through RSM and the energy consumption of the process was monitored in real time, with the biodegradability of the product measured according to ISO 14855-2. Finally, as a final product, a reusable plate was created, which was then tested according to temperature and mechanical assays in order to evaluate its possible uses.

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.