1. Introduction

Reliable experimental characterization of architected lattice materials requires specialized fixture systems that ensure accurate load transfer. Traditional metallic fixtures are often prohibitively expensive and slow to produce, hindering rapid, iterative material research. This study addresses this challenge by presenting the design, finite element validation, and topological optimization of a cost-effective test fixture made from Fused Filament Fabrication (FFF) Polylactic Acid (PLA). The fixture is designed to enable the cyclic mechanical characterization of LPBF-manufactured Kelvin-type lattices.

1. Methods

The fixture's design process was iterative, combining CAD modeling and Finite Element Analysis (FEA) to refine its geometry and performance. The supports were designed for axial load transfer compatible with an Instron 8801 testing machine. The loading protocol was proportionally scaled from a recognized standard for Steel Plate Shear Yielding Dampers (SPSYDs). A density-based topology optimization was performed to minimize mass while maintaining structural rigidity, targeting a mass reduction constraint of 60%.

1. Results

The iterative design and optimization process successfully improved the safety factor from an initial 2.08 to a final value of 4.25, confirming its structural integrity under the maximum load of 5.3 kN. The topology optimization achieved a mass reduction of 40% compared to the initial design. Preliminary experimental analysis and numerical simulations confirmed that the optimized PLA supports exhibited minimal deformation, with displacements around 0.73 mm, which was significantly lower than the machine clamps.

1. Conclusions

This research demonstrated that combining numerical analysis and topological optimization can produce cost-effective, FFF-manufactured PLA components that are capable of replacing traditional metal devices in cyclic mechanical testing applications. The developed methodology can be extended to other test devices where stiffness and precision are crucial. The validated fixture provides a reliable platform for future experimental tests of lattice-based hysteretic dampers.

Introduction.

Size-exclusion chromatographic separation with Sephadex gels is a widely used technique for dereplication and screening methodologies of natural products. Sephadex G-10 resin is a polymeric network composed of dextran units cross-linked by epichlorohydrin and allows using physiological solutions as mobile phases for the direct coupling chromatographic separation to study living tissues or organs. Thus, this type of system enables real-time monitoring of active compounds, an application of significant importance in organic chemistry and pharmacology.

Methods.

Medium-pressure liquid chromatography separation (MPLC) with Sephadex G-10 coupled directly to biological detection using perfused organs was carried out for bio-guided study of hydro-ethanolic extracts from Nicotiana glauca Graham (Solanaceae). Sephadex G-10 provides the lowest fractionation range of gels type Sephadex, allowing the separation of substances with molecular weights below 700 Da, typically within the range of 100–1000 Da. Furthermore, this resin enabled the use of Krebs-HEPES as an elution medium, a medium that kept the studied organs in optimal conditions.

Perfused rat organs were used: Rings of aorta artery and trachea, and portions from the deferent conduct and ileum.

Results.

Two natural alkaloids, anabasine and nornicotine, were readily isolated and identified as the compounds responsible for the contractile activity observed in the smooth muscle of rat ileum and trachea.

The coupling of this chromatographic system with Sephadex G-10 to biological detection in living organs simplified the bioassay-guided: it carried out by a single person, with a physiological and non-contaminating medium, minimizing the number of animals slaughtered, with chemical characterization by mass spectrometry analysis, and reducing the study time.

Conclusions.

This application of Sephadex G-10 chromatography rationalizes the bio-guided identification of isolated natural products and advances its use toward green chemistry dereplication methodologies as well as in future automated or robotic approaches.

Background: Self-healing polymers are an innovative break through in material science, where autonomous repair and prolonging service life functionality in biomedical applications is possible. In prosthetics and orthotics, the materials take care of challenges such as mechanical breakdown, degradation upon wear and tear, and frequent replacement.

Materials and Methods: PubMed, Google Scholar, Scopus, and Web of Science were used to conduct a systematic search of studies up until December 2024. The inclusion criteria involved article types, including peer-reviewed articles, conference proceedings, and patents concerned with self-healing polymer use in prosthetic and orthotic applications.

Results: 34 studies were included among 1,247 identified articles. These self-healing materials were divided into intrinsic (shape memory, dynamic covalent bond) and extrinsic (microcapsule-based, vascular networks). The systems based on polyurethane possessed better mechanical behavior and healing performance (85-95% of recovery). Research indicated a major increase in fatigue resistance of 2-5 fold and an improvement of service life by 40-70 percent.

Discussion: It is observed that presently, significant benefits of self-healing polymers are associated with possible use in prosthetics and orthotics. Nonetheless, there are still issues to be dealt with, such as efficiency in healing at physiological levels and regulatory approval systems.

Conclusion: Self-healing polymers have high potential to transform prosthetic and orthotic device production with high durability, less maintenance, and satisfaction from people using the devices.

Introduction: Photosensitive polymers are emerging as a new method of tissue engineering with great prospects for hard tissue in terms of bone, and cartilage, and dental tissue regeneration. Such materials experience property transformations upon light exposure, which allows us to control biocompatibility and direct cell differentiation with a high degree of precision and allows us to gett rid of the limitations of traditional methods.

Materials and Methods: Systematic searches of databases were performed in PubMed, Google Scholar, Scopus, and Web of science (2010-2024) according to the following combinations of keywords: photosensitive polymers and tissue engineering; photosensitive polymers and hard tissue regeneration; and photosensitive polymers and bone tissue engineering. English-language peer-reviewed research articles concerning photosensitive polymer sections in hard tissue regeneration were included.

Results: There were a total of 89 studies included out of 1,247 identified articles. Important polymers were poly(ethylene glycol) diacrylate (PEGDA), gelatin methacryloyl (GelMA), and hyaluronic acid methacrylate (HAMA). These materials showed the ability to form 3D scaffolds with adjustable mechanical properties, biocompatibility and growth factor release. 3D bioprinting using photosensitive polymers gave us the potential to fabricate complex bone structures.

Discussion: In this analysis, there was high potential concerning photosensitive polymers in dentistry as far as hard tissue regeneration is concerned. They have the benefits of tunable mechanical properties, excellent control of polymerization and the ability to make complex structures. Ongoing issues are the cytotoxicity of photosensitive polymers and low transparency of light through thick constructs.

Conclusion: Photosensitive polymers can be considered an optimistic approach for hard tissue regeneration. The recent developments of 3D bioprinting and the development of new polymers point towards their high clinical application potential. Future research must provide answers to the existing difficulties, develop optimal formulations, and carry out a single clinical research study.

Modern polymers are evolving into multifunctional systems with highly sophisticated behavior, often termed “smart” materials due to their ability to respond to specific stimuli. Mechanophores are generally force-responsive molecules that have greater interest in the daily use of polymeric materials. Mechanoresponsive polymers are particularly attractive as they undergo molecular-level conformational changes and selective bond scission when subjected to mechanical stress. This enables productive, reversible chemical transformations rather than nonspecific degradation.

Dynamic covalent bonds, such as the furan–maleimide Diels–Alder (DA) adduct, play a crucial role in synthetic chemistry, and are now expanding into advanced polymer materials. Among various mechanophores, furan–maleimide adducts are particularly attractive due to their low reaction barrier, reversible bond scission, and efficient stress absorption. Unlike others, DA adducts enable controlled, reversible bond breaking and reforming, making them ideal for self-healing materials.

We aim to develop a novel furan–maleimide-based mechanophore by functionalizing it with different mercaptan groups under simplified reaction conditions. This newly designed mechanophore will be incorporated into polymers such as PMA (polymethyl acrylate) and SBR (styrene–butadiene rubber). After polymerization, the material will undergo vulcanization, ensuring its integration into the polymer network.

To evaluate its performance, the mechanophore will be subjected to various material tests, including tensile strength, stress, and strain under mechanical force. The goal is to confirm its ability to undergo reversible bond scission, making it a potential candidate for tire applications where durability and adaptability to mechanical stress are crucial.

Alzheimer's disease (AD) is a neurodegenerative disease associated with progressive cognitive and memory dysfunction. Quercetin is a natural flavonoid possessing strong antioxidant and neuroprotective activities that has been identified to be of potential value in the treatment of AD by its acetylcholinesterase and butyrylcholinesterase inhibitory action. Its lack of aqueous solubility, low bioavailability, and limited passage across the blood-brain barrier (BBB) limit its clinical applications. To overcome such challenges, the present study had the objective of formulating a nano formulation targeted to the brain of quercetin with a chemically modified polyethyleneimine-based polymer. The functionalized polymer was prepared and determined by FTIR and mass spectroscopic methods that successful conjugation was achieved. Nanoparticles were formulated by solvent injection methods and compared for particle size, zeta potential, PDI, and entrapment efficiency. Optimized formulations showed particle sizes in the nano-range with monodispersity and positive surface charge. Sustained release and pH sensitivity of the drug were observed in vitro, especially under physiological pH conditions of 7.4. Pharmacokinetics demonstrated increased quercetin brain uptake using the modified formulation over plain drug. Moreover, acute toxicity experiments proved that the synthesized modified nanoparticles were safe and biocompatible, with no considerable adverse effects in treated animals. The results confirm the potential of the improved nano formulation as a promising platform for effective and targeted delivery of quercetin to the brain for the treatment of Alzheimer's disease.

The global reliance on fossil-derived polymers continues to contribute to environmental degradation and climate change. As the world seeks sustainable alternatives, algae-derived polymers have emerged as a promising solution due to their renewable nature and compatibility with green chemistry and circular economy principles. Unlike traditional biomass sources, algae can be cultivated on non-arable land using saline or wastewater, reducing land-use conflict and freshwater consumption while simultaneously sequestering atmospheric CO₂. This review examines recent progress in the extraction, processing, and functionalization of algae-derived polymers, with a particular focus on polysaccharides such as alginate and carrageenan. A comparative analysis was conducted to evaluate their mechanical performance, biodegradability, and application scalability across various industries including sustainable packaging, biomedical devices, and textiles. The review draws on data from peer-reviewed publications within the past decade. The findings highlight that algal polysaccharides offer excellent film-forming capabilities, mechanical adaptability, and environmental biodegradability. Seaweed-derived polymers like carrageenan have shown strong potential in biomedical fields due to their gel-forming and biocompatible nature. Life-cycle assessments support the environmental benefits of algae-based bioplastics compared to conventional plastics. In conclusion, algae-derived polymers represent a rapidly advancing frontier in sustainable materials science. While their adoption in high-value sectors is accelerating, further interdisciplinary research is needed to overcome related cost, processing, and commercialization challenges.

Percutaneous coronary intervention (PCI) is a minimally invasive technique used to reopen narrowed or blocked coronary arteries caused by atherosclerosis. In which stent is implanted to reopen arteries, but after some time, it gets narrowed again, called restenosis, which is a reduction in lumen diameter after PCI. Drug-eluting stents (DES) were developed to specifically address the problems of restenosis encountered with BMS ISR. Drug-eluting stent was found to be better than other types of stents. These stents are coated with drugs like paclitaxel, sirolimus, zotarolimus, or everolimus. Primarily, PLGA or PLA polymers are used to increase the release of the drug for a longer duration. Most drug-eluting stent manufacturers use PLGA or PLA to load the medicine and coating of the stent. The required course of release of sirolimus or everolimus for transplant success will be 90 days or more. However, the PLGA-coated Genex stents loaded with sirolimus provided the release of 30 days (Purple Micro Port Pvt. Ltd.). Chitosan is known for its extended release of drugs. Further, the drug sirolimus was analyzed to have 14 hydrogen bond acceptors. Thus, chitosan rich in hydrogen bond donors will be used for the modification. Moreover, the sulphonamide-containing linkers are reported to be pH sensitive (pH 7.2-7.4). Thus, a novel modified polymer contains PLGA and chitosan linked with a pH-sensitive sulphonamide linkage. The novel polymer rich in Hydrogen bond donors will improve drug loading and release. Thus, the pH sensitivity and enhanced drug loading may increase the release from 30 to 90 days.

Hydrogels are 3-dimensional cross networked polymeric materials that can absorb and retain a large amount of water. Nature-derived hydrogels are biodegradable, low cost, non-toxic and biocompatible. Here we developed agricultural waste-derived hydrogel in which cellulose was extracted from rice straw and Carboxymethyl Tamarind Kernel Gum (CMTKG) (made from tamarind’s seed) was collected from market. CMTKG and Rice Straw Cellulose (RSC)-based superabsorbent hydrogels by in situ incorporation of Copper (Cu) were synthesized by graft copolymerization using epichlorohydrin as a crosslinker. Cu-loaded CMTKG-RSC superabsorbent hydrogel (CSH) was applied as a carrier vehicle for Cu micronutrient release for applications in the field of agriculture. The synthesized CSH was characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), and UV–visible spectrophotometer analysis. The prepared CSH was analyzed regarding its swelling, deswelling, water retention, recyclability, and biodegradation. The synthesized CSH observed to have a water absorption capacity (663 – 832% in distilled water) with entanglement of Cu with weak physical forces. The water absorption kinetics exhibited that the rate-controlling step was Fickian diffusion, revealing a slower diffusion rate of water transport into the hydrogel network. The CSH showed a slow release of Cu with ~80% release within 184 h in distilled water. Different kinetic models were studied to observe the release kinetic parameters. The Peppas–Sahlin model was the best-fitted model among all studied models, revealing Cu release controlled by Cu diffusion with polymeric relaxations. Considering these findings, the synthesized hydrogel can be used as a water reservoir for agriculture and reducing irrigation in plants. Slow release of micronutrients (such as Cu) from CSH also enhances the plant growth.

Nanofibrous materials have gained increasing attention for biomedical and agrifood applications owing to their high surface-to-volume ratio, tunable porosity, and ability to incorporate functional agents. Among biodegradable polymers, poly(D,L-lactic acid) (D,L-PLA) offers distinct advantages, including biocompatibility, processability, and controlled degradation kinetics, making it a versatile candidate for multifunctional nanofibrous systems.

In this work, we investigated the preparation of D,L-PLA-based nanofibrous materials using solution blow spinning (SBS), a scalable and cost-effective technique that enables the rapid fabrication of fibers without the need for high voltage or complex equipment. Processing conditions were optimized to obtain uniform fibers with controlled morphology and diameter distribution. The effects of solution properties and processing parameters on fiber morphology and distribution were systematically evaluated. Additionally, the incorporation of bioactive agents was explored to tailor the fibers for targeted applications.

The resulting materials were characterized from their structural, thermal, mechanical, and morphological properties. FTIR analyses confirmed the polymeric structure, while SEM micrographs revealed uniform and continuous fibers in the submicrometric range, with an average fiber diameter distribution of approximately 300 nm. The resulting materials exhibited favorable mechanical stability and degradation behavior. Preliminary assessments demonstrated their suitability as scaffolds in biomedical applications, where the fibrous network supports cell adhesion and growth. In parallel, the fibers showed promise for agrifood applications such as active packaging, benefiting from their barrier properties and potential to act as carriers for active agents.

Overall, this study highlights the versatility of D,L-PLA nanofibers produced by SBS and underscores their dual applicability in health-related and sustainable food systems. The findings contribute to the development of biodegradable nanostructures with multifunctional performance and scalable production pathways, reaffirming their potential as a sustainable alternative to conventional plastics and as a versatile platform for biomedical and industrial applications.

Acknowledgments: Project TED2021-129945B-I00