The present study investigates the development and characterization of sustainable poly(lactic acid) (PLA) composite filaments reinforced with bio-waste derived prawn shell particles (PSP) for fused deposition modeling (FDM) applications. PLA/PSP composite filaments containing 5-20 wt% PSP were fabricated using a multi-zone twin-screw extrusion process, and their dimensional stability, surface morphology, thermal behavior, and mechanical performance were systematically evaluated. The incorporation of PSP significantly influenced the extrusion quality and structure-property relationship of the developed filaments. Among the investigated compositions, the 15 wt% PSP composite exhibited the best overall performance, achieving a tensile strength of 46.2 MPa with improved surface uniformity due to enhanced filler dispersion and interfacial adhesion. Thermal analysis revealed that the 10 wt% PSP composite exhibited superior thermal stability with an onset degradation temperature of 372 degrees C, while higher PSP loadings promoted increased char formation because of the mineral-rich nature of the prawn shell particles. SEM observations further confirmed homogeneous particle distribution and reduced interfacial defects at the optimum filler loading. Overall, the study demonstrates the potential of prawn shell waste as a sustainable bio-reinforcement for developing high-performance biodegradable PLA filaments for additive manufacturing applications.
Shape Memory Polymers (SMPs), a class of smart materials capable of shape-programed recovery through temperature stimulation, have opened new avenues for personalized preparation and dynamic functional regulation of bone tissue engineering scaffolds when combined with 4D printing technology. This review strictly follows the PRISMA systematic review guidelines, and literature retrieval and screening were independently completed by two researchers. Literature sources included Web of Science, PubMed, and ScienceDirect, with a retrieval time range from January 2018 to May 2025. Excluding review articles, letters, and conference abstracts, 37 original research articles were included. This paper systematically reviews the shape memory mechanisms of thermotropic SMPs and the current status of 4D printing applications in bone scaffold fabrication. Thermotropic SMPs rely on the chemical structure of “fixed phase-reversible phase” dual-network, where the fixed phase maintains the permanent shape, and the reversible phase (e.g. PCL crystalline segments, PLA glassy segments) realizes temporary shape fixation and recovery. Different from existing descriptive reviews, this work critically analyzes the correlation between scaffold shape memory characteristics (recovery rate, response speed, mechanical adaptability) and bone repair performance, deciphers the regulatory mechanisms of material modification and structural design, and summarizes existing performance trade-offs and technical contradictions. This paper also systematically categorizes core challenges in material design, printing processing, biological performance, and clinical translation, and proposes actionable future research directions. This work aims to provide standardized theoretical references and technical guidance for optimizing the design and clinical application of 4D-printed bone scaffolds based on thermotropic SMPs.
Hydrogels are polymeric systems that have been extensively investigated and applied in biomedical contexts. Its properties generally include biocompatibility, hydrophilicity, and mechanical properties well-suited for applications in regenerative medicine and controlled delivery systems of drugs and bioactive components. Current research on hydrogels involves incorporating plant metabolites to enhance their healing properties. The bark of the Mimosa tenuiflora plant has been used empirically to treat skin injuries and burns. Emerging research has identified that this plant possesses molecules that can help wound healing. However, the use of the extract of this plant in biomaterials for skin regeneration is very little studied. In this study, the properties of hydrogels prepared from chitosan and Mimosa tenuiflora extract were investigated. Several bioactive molecules in the Mimosa tenuiflora extract were identified, including tannins and araginogalactans. The physicochemical properties of the samples were evaluated, as well as their porosity, degradation kinetics, water retention, percentage of gelation, water vapor transmission rate, and swelling ratio. The results showed porosity in the range of 62%-76%, a swelling ratio of 90%-97% and a degradation appropriate for use in the repair of skin wounds. It was observed that the extract helps to increase the antibacterial property of hydrogel, against Gram - and Gram + bacteria. Furthermore, the incorporation of the chitosan hydrogel matrix extract increases cell migration in an in vitro healing study. Therefore, it can be inferred that the extract of Mimosa tenuiflora enhances the antibacterial activity, cell migration in vitro, and physicochemical properties, such as water retention, porosity, and degradation in vitro, of the hydrogels compared to the control hydrogel. These findings suggest these hydrogels as promising candidates for wound healing dressings.
Siwi dates are highly nutritious, versatile, and naturally energy-rich. However, prolonged storage often results in quality deterioration due to pests and microbial contamination, leading to texture changes, insect infestation, and loss of flavor and nutrients. To address these challenges, environmentally friendly preservation strategies have been explored to safeguard this valuable crop. In this study, we report the synthesis of a sustainable edible coating formulated from moringa extract (ME) incorporated into polyvinyl alcohol (PVA) and chitosan (CS) matrices, prepared via gamma-irradiation. Different ratios of moringa extract (ME) (3, 5, 10, and 15%) were successfully incorporated into PVA/CS matrix to synthesize four distinct PVA/CS/ME coating solutions. For efficient characterization, PVA/CS/ME films containing 10% ME were fabricated using the casting method, and their properties were examined by FTIR, XRD, and tensile testing. FTIR and XRD analyses confirmed the effective interaction between ME and the PVA/CS matrix. Increasing the ME concentration within the PVA/CS matrix imparted significant antibacterial activity against Staphylococcus aureus and Escherichia coli, attributed to ME phytochemicals, thereby highlighting the films' potential as active food packaging materials that enhance safety and extend shelf life. Furthermore, four PVA/CS/ME coating solutions were applied as edible coatings to extend the shelf life and maintain the quality of Siwi dates during 6 months of storage at room temperature (65-70% RH). Quality parameters, including insect infestation (%), weight loss (%), moisture content (%), browning index, total soluble solids, and pH, were monitored throughout the storage period. The coating solution containing 15% ME demonstrated the most pronounced effect, effectively reducing insect infestation and preserving fruit quality. These findings highlight a promising eco-friendly approach for the long-term preservation and marketing of Siwi dates.
This study developed and characterised poly(vinyl alcohol) (PVA)-polyvinylpyrrolidone (PVP)-chitosan composite hydrogels crosslinked with oxalic acid through thermal crosslinking as antifungal wound dressings loaded with amphotericin B (AMB). Hydrogel films were prepared from aqueous stock solutions with varying chitosan content and subjected to dry thermal treatment to induce crosslinking with oxalic acid. Increasing chitosan content significantly elevated the viscosity of the polymeric mixtures and influenced the swelling percentage and equilibrium water content. Conversely, the gel fraction remained largely unchanged, indicating enhanced water uptake without compromising structural integrity. FTIR spectroscopy confirmed successful network formation and chitosan incorporation. Leachable studies identified PVA and PVP as the primary leachate components. While AMB partitioning showed no statistical differences across formulations, the hydrogels maintained a mildly acidic surface pH. Notably, the AMB-loaded PPChi20 hydrogel exhibited a significantly larger zone of inhibition against C. albicans compared to AMB-free controls. As blank formulations showed no antifungal activity, the efficacy was primarily dependent on the hydrogel's AMB loading capacity. These findings suggest that PVA-PVP-chitosan hydrogels crosslinked with oxalic acid are promising candidates for topical AMB delivery in managing fungal-infected wounds.
