Development and characterization of eco-friendly guar gum-agar-beeswax-based active packaging film for cheese preservation.

In this work, an attempt has been made to develop a novel natural polysaccharide-based composite packaging biofilm prepared through a solution casting method. The biofilm is prepared from guar gum (GG) and agar-agar (AA) beeswax (BE). The incorporation of 20 % wt./wt.glycerol BE in the blended polymer GG/AA (50:50) (GG/AA/BE20 (50:50)) film shows a reduction in water solubility (66.67 %), water vapour permeability (69.28 %) and oxygen permeability (72.23 %). Moreover, GG/AA/BE20 (50:50) shows an increment in the tensile strength and elongation of a break by 48.32 % and 26.05 %, respectively, compared to pristine GG film. The scanning electron microscopy (SEM) image reveals defects-free smooth surfaces of the film. The Fourier transform-infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) demonstrated the strong hydrogen bonding between GG, AA, and BE. The biodegradable film shows 99 % degradation within 28 days when placed in the soil. The developed film plays a crucial role in extending the shelf life of cheese, effectively maintaining its moisture content, texture, colour, and pH over a span of up to two months from the point of packaging. These results suggest that GG/AA/BE20 (50:50) composite film is a promising packaging film for cheese preservation.

Antioxidant Edible Films Derived from Belitung Taro Tubers (Xanthosoma sagittifolium) Incorporated with Moringa Leaf Extract (Moringa oleifera).

Edible films are thin films frequently manufactured using natural bioresources and are employed in food packaging to safeguard food quality. This research prepared edible films from renewable biomass consisting of Belitung taro tuber starch (Xanthosoma sagittifolium) and incorporated sorbitol as a plasticizer, carboxymethyl cellulose as a reinforcing agent, and moringa leaf extract (Moringa oleifera) as an antioxidant. The physicochemical characteristics of the resulting edible films were examined. The most favorable treatment was identified in an edible film containing 3% (v/v based on the total volume of 100 mL) of moringa leaf extract. This exhibited a tensile strength of 6.86 N/mm2, percent elongation of 73.71%, elasticity of 9.37×10-3 kgf/mm2, water absorption of 349.03%, solubility of 93.18%, and water vapor transmission speed of 3.18 g/h m2. Its shelf life was five days at ambient temperature. The edible film was found to have 135.074 ppm of half maximal inhibitory concentration (IC50) based on the antioxidant analysis of inhibition concentration (IC50) value measurements, and was classified as having moderate antioxidant activity. Additionally, the biodegradability assessment revealed that the edible films degraded within 14 days. Based on this data, it can be deduced that adding moringa leaf extract enhances the physicochemical and functional characteristics of the film. These edible films can be used as substitutes for nonrenewable and nonbiodegradable packaging materials.

Water-dependent effects of biodegradable microplastics on arsenic fractionation in soil: Insights from enzyme degradation and synchrotron-based X-ray analysis.

The abundance of biodegradable microplastics (BMPs) is increasing in soil due to the widespread use of biodegradable plastics. However, the influence of BMPs on soil metal biogeochemistry, especially arsenic (As), under different water regimes is still unclear. In this study, we investigated the effects of two types of BMPs (PLA-MPs and PBAT-MPs) on As fractionation in two types of soils (black soil and fluvo-aquic soil) under three water regimes including drying (Dry), flooding (FL), and alternate wetting and drying (AWD). The results show that BMPs had limited indirect effects on As fractionation by altering soil properties, but had direct effects by adsorbing and releasing As during their degradation. Enzyme degradation experiments show that the degradation of PLA-MPs led to an increased desorption of 4.76 % for As(III) and 15.74 % for As(V). Synchrotron-based X-ray fluorescence (µ-XRF) combined with micro-X-ray absorption near edge structure (µ-XANES) analysis show that under Dry and AWD conditions, As on the BMPs primarily bind with Fe hydrated oxides in the form of As(V). Conversely, 71.57 % of As on PBAT-MP under FL conditions is in the form of As(III) and is primarily directly adsorbed onto its surface. This study highlights the role of BMPs in soil metal biogeochemistry.

Impacts of conventional and biodegradable microplastics in maize-soil ecosystems: Above and below ground.

The increasing accumulation of microplastics (MPs) in agroecosystems has raised significant environmental and public health concerns, facilitating the application of biodegradable plastics. However, the comparative effects of conventional and biodegradable MPs in agroecosystem are still far from fully understood. Here we developed microcosm experiments to reveal the ecological effects of conventional (polyethylene [PE] and polypropylene [PP]) and biodegradable (polyadipate/butylene terephthalate [PBAT] and polycaprolactone [PCL]) MPs (0, 1%, 5%; w/w) in the maize-soil ecosystem. We found that PCL MPs reduced plant production by 73.6-75.2%, while PE, PP and PBAT MPs elicited almost negligible change. The addition of PCL MPs decreased specific enzyme activities critical for soil nutrients cycling by 71.5-95.3%. Biodegradable MPs tended to reduce bacterial α-diversity. The 1% treatments of PE and PBAT, and PCL enhanced bacterial networks complexity, whereas 5% of PE and PBAT, and PP had adverse effect. Moreover, biodegradable MPs appeared to reduce the α-diversity and networks complexity of fungal community. Overall, PCL reduced the ecosystem multifunctionality, mainly by inhibiting the microbial metabolic activity. This study offers evidence that biodegradable MPs can impair agroecosystem multifunctionality, and highlights the potential risks to replace the conventional plastics by biodegradable ones in agricultural practices.

Biodegradable microspheres via orally deliver celastrol with ameliorated neuropathic pain in diabetes rats.

The treatment of peripheral neuropathy resulting from diabetes primarily emphasizes neurotrophic medications. However, a growing body of clinical studies indicates that neuroinflammation plays a significant role in the pathogenesis of neuropathic pain. This has spurred active exploration of treatment strategies leveraging nanomedicine for diseases, aiming for superior therapeutic outcomes. In this context, we have developed biodegradable nanoparticles made of polylactic-co-glycolic acid, loaded with triptolide (pCel), designed to alleviate somatic cell neuropathic pain induced by diabetes. Treatment with pCel notably reduced levels of reactive oxygen species and apoptosis in vitro. Furthermore, the progression of streptozotocin-induced diabetes, characterized by elevated renal function indices (blood urea nitrogen, creatinine), liver function indices (bilirubin, alkaline phosphatase) and decreased levels of albumin and globulin, was mitigated following pCel administration. Importantly, oral treatment with pCel significantly inhibited mechanical allodynia and the activation of the sciatic glial cells in diabetic rats. These findings indicate that this synthetic, biodegradable nanomedicine exhibits excellent stability, biocompatibility and catalytic activity, making it a promising and innovative approach for the management of chronic pain conditions associated with diabetic neuropathy.

Effects of microplastics derived from biodegradable mulch film on different plant species growth and soil properties.

Biodegradable mulch residues contribute significantly to the presence of microplastics in soil ecosystems. The environmental impact of microplastics, especially biodegradable microplastics (bio-MPs), on soil and plants is of increasing concern. In this study, the responses of five crop species potted in soil treated with different mass concentrations of bio-MPs were assessed for one month. The shoot and root biomasses of cabbages and strawberries were inhibited by bio-MPs treatment. There was little variation in the growth indicators of identical plants with the addition of different mass concentrations of bio-MPs; however, a significant difference was observed among different plants with the addition of the same concentration of bio-MPs. The detrimental effects of bio-MPs were more pronounced in strawberries and cabbages than in the other plant species. Moreover, bio-MPs can affect the availability of soil nutrients and enzyme activities. Structural equation modeling showed that changes in soil properties may indirectly affect plant growth and nutrient uptake when exposed to bio-MPs. This study provides a theoretical basis for understanding the ecological effects of biodegradable mulch films.

The fate of post-use biodegradable PBAT-based mulch films buried in agricultural soil.

The fate of black biodegradable mulch film (MF) based on starch and poly(butylene-adipate-co-terephthalate) (PBAT) in agricultural soil is investigated herein. Pristine (BIO-0) and UV-aged film samples (BIO-A192) were buried for 16 months at an experimental field in southern Italy. Visual, physical, chemical, morphological, and mechanical analyses were carried out before and after samples burial. Film residues in the form of macro- and microplastics in soil were analyzed at the end of the trial. Progressive deterioration of both pristine and UV-aged samples, with surface loss and alterations in mechanical properties, occurred from 42 days of burial. After 478 days, the apparent surface of BIO-0 and BIO-A192 films decreased by 57 % and 66 %, respectively. Burial determined a rapid depletion of starch from the polymeric blend, especially for the BIO-A192, while the degradation of the polyester phase was slower. Upon burial, an enrichment of aromatic moieties of PBAT in the film residues was observed, as well as microplastics release to soil. The analysis of the MF degradation products extracted from soil (0.006-0.008 % by mass in the soil samples) revealed the predominant presence of adipate moieties. After 478 days of burial, about 23 % and 17 % of the initial amount of BIO-0 and BIO-A192, respectively, were extracted from the soil. This comprehensive study underscores the complexity of biodegradation phenomena that involve the new generation of mulch films in the field. The different biodegradability of the polymeric components, the climate, and the soil conditions that did not strictly meet the parameters required for the standard test method devised for MFs, have significantly influenced their degradation rate. This finding further emphasizes the importance of implementing field experiments to accurately assess the real effects of biodegradable MFs on soil health and overall agroecosystem sustainability.

Study of the effect of magnetic fields on static degradation of Fe and Fe-12Mn-1.2C in balanced salts modified Hanks' solution.

Iron and its alloys are attractive as biodegradable materials because of their low toxicity and suitable mechanical properties; however, they generally have a slow degradation rate. Given that corrosion is an electrochemical phenomenon where an exchange of electrons takes place, the application of magnetic fields from outside the body may accelerate the degradation of a ferrous temporary implant. In the present study, we have investigated the effect of alternating and direct low magnetic field (H = 6.5 kA/m) on the corrosion process of pure iron (Fe) and an iron-manganese alloy (FeMnC) in modified Hanks' solution. A 14-day static immersion test was performed on the materials. The corrosion rate was assessed by mass and cross-sectional loss measurements, scanning electron microscopy, X-ray diffractometry, Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy before and after degradation. The results show that the presence of magnetic fields significantly accelerates the degradation rate of both materials, with the corrosion rate being twice as high in the case of Fe and almost three times as high for FeMnC. In addition, a homogenous degradation layer is formed over the entire surface and the chemical composition of the degradation products is the same regardless of the presence of a magnetic field.

Exploring the biodegradability of candidate metallic intravascular stent materials using X-ray microfocus computed tomography: An in vitro study.

In vitro testing for evaluating degradation mode and rate of candidate biodegradable metals to be used as intravascular stents is crucial before going to in vivo animal models. In this study, we show that X-ray microfocus computed tomography (microCT) presents a key added value to visualize degradation mode and to evaluate degradation rate and material surface properties in 3D and at high resolution of large regions of interest. The in vitro degradation behavior of three candidate biodegradable stent materials was evaluated: pure iron (Fe), pure zinc (Zn), and a quinary Zn alloy (ZnAgCuMnZr). These metals were compared to a reference biostable cobaltchromium (CoCr) alloy. To compare the degradation mode and degradation rate evaluated with microCT, scanning electron microscopy (SEM) and inductively-coupled plasma (ICP) were included. We confirmed that Fe degrades very slowly but with desirable uniform surface corrosion. Zn degrades faster but exhibits localized deep pitting corrosion. The Zn alloy degrades at a similar rate as the pure Zn, but more homogeneously. However, the formation of deep internal dendrites was observed. Our study provides a detailed microCT-based comparison of essential surface and corrosion properties, with a structural characterization of the corrosion behavior, of different candidate stent materials in 3D in a non-destructive way.

Implementation of microcontroller board on a sustainable and degradable PLA/Flax composite substrate: a case study.

In this paper, we present a novel polylactic-acid/flax-composite substrate and the implementation of a demonstrator: a microcontroller board based on commercial design. The substrate is developed for printed circuit board (PCB) applications. The pre-preg is biodegradable, reinforced, and flame-retarded. The novel material was developed to counter the increasing amount of e-waste and to improve the sustainability of the microelectronics sector. The motivation was to present a working circuit in commercial complexity that can be implemented on a rigid substrate made of natural, bio-based materials with a structure very similar to the widely used Flame Retardant Class 4 (FR4) substrate at an early technological readiness level (TRL 2-3). The circuit design is based on the Arduino Nano open-source microcontroller board design so that the demonstration could be programmable and easy to fit into education, IoT applications, and embedded designs. During the work, the design was optimized at the level of layout. The copper-clad pre-preg was then prepared and processed with subtractive printed wiring technology and through hole plating. The traditional surface mounting methodology was applied for assembly. The resulting yield of PCB production was around 50%. Signal analysis was successful with analogue data acquisition (voltage) and low-frequency (4 kHz) tests, indistinguishable from sample FR4 boards. Eventually, the samples were subjected to highly accelerated stress test (HAST). HAST tests revealed limitations compared to traditional FR4 printed circuit materials. After six cycles, the weight loss was around 30% in the case of PLA/Flax, and as three-point bending tests showed, the possible ultimate strength (25 MPa at a flexural state) was reduced by 80%. Finally, the sustainability aspect was assessed, where we found that ~95vol% and ~90wt% of the traditional substrate can be substituted, significantly easing the load of waste on the environment.

Development of bio-composite mulch film from cotton gin wastes: Study of pesticide residue and outdoor stability and degradation.

Non-degradable plastic mulch films used in agriculture are polluting the environment by leaving residues and microplastics in the soil. They are also difficult to recycle due to contamination during their use. Biodegradable mulch films are needed as alternatives so that they can be used effectively during the growing season and later be ploughed to be degraded in soil. However, market-available so-called biodegradable mulch films are very slow to degrade in the natural environment and thus do not fit with crop rotation demands or annual cultivation. In this study, we have developed mulch films from cotton gin trash (CGT) and/or gin motes (GM) in combination with biodegradable polycaprolactone and demonstrated their effectiveness over 3 months in outdoor conditions. Both the stability and degradation behaviours of mulch film samples were observed when they were placed on top of the soil and buried in the soil, respectively. Pesticide residue analysis also was carried out on CGT powder to identify and quantify individual pesticides against a matrix of known pesticides. The mulch films prepared in this study showed comparable and stable mechanical properties compared to commercial biodegradable mulch film, though were much quicker to degrade when buried in the soil. No pesticides were detected in the CGT samples. The films produced were vapour-permeable and may be useful in practical agricultural settings by being able to maintain consistent soil moisture and allowing precipitation to penetrate gradually. The lab-scale production cost for the film was 98.8 AUD/kg, which could be lowered by integrating a continuous film line in large-scale production.

Sheep Bone Ultrastructure Analyses Reveal Differences in Bone Maturation around Mg-Based and Ti Implants.

Magnesium alloys are some of the most convenient biodegradable materials for bone fracture treatment due to their tailorable degradation rate, biocompatibility, and mechanical properties resembling those of bone. Despite the fact that magnesium-based implants and ZX00 (Mg-0.45Zn-0.45Ca in wt.%), in particular, have been shown to have suitable degradation rates and good osseointegration, knowledge gaps remain in our understanding of the impact of their degradation properties on the bone's ultrastructure. Bone is a hierarchically structured material, where not only the microstructure but also the ultrastructure are important as properties like the local mechanical response are determined by it. This study presents the first comparative analysis of bone ultrastructure parameters with high spatial resolution around ZX00 and Ti implants after 6, 12, and 24 weeks of healing. The mineralization was investigated, revealing a significant decrease in the lattice spacing of the (002) Bragg's peak closer to the ZX00 implant in comparison to Ti, while no significant difference in the crystallite size was observed. The hydroxyapatite platelet thickness and osteon density demonstrated a decrease closer to the ZX00 implant interface. Correlative indentation and strain maps obtained by scanning X-ray diffraction measurements revealed a higher stiffness and faster mechanical adaptation of the bone surrounding Ti implants as compared to the ZX00 ones. Thus, the results suggest the incorporation of Mg2+ ions into the bone ultrastructure, as well as a lower degree of remodeling and stiffness of the bone in the presence of ZX00 implants than Ti.

Chitosan/poly-γ-glutamic acid crosslinked hydrogels: Characterization and application as bio-glues.

Ecofriendly hydrogels were prepared using chitosan (CH, 285 kDa) and two fractions of low molecular weight microbial poly-γ-glutamic acid (γ-PGA) (R1 and R2 of 59 kDa and 20 kDa, respectively). The hydrogels were synthesized through sustainable physical blending, employing three CH/γ-PGA mass ratios (1/9, 2/8, and 3/7), resulting in the formation of physically crosslinked materials. The six resulting CH/R1 and CH/R2 hydrogels were physico-chemically characterized and the ones with the highest yields (CH/R1 and CH/R2 ratio of 3/7), analyzed for rheological and morphological properties, showed to act as bio-glues on wood and aluminum compared to commercial vinyl- (V1) and acetovinyl (V2) glues. Lap shear analyses of CH/R1 and CH/R2 blends exhibited adhesive strength on wood, as well as adhesive/cohesive failure like that of V1 and V2. Conversely, CH/R2 had higher adhesive strength and adhesive/cohesive failure on aluminum, while CH/R1 showed an adhesion strength with adhesive failure on the metal similar to that of V1 and V2. Scanning electron microscopy revealed the formation of strong physical bonds between the hydrogels and both substrates. Beyond their use as bio-adhesives, the unique properties of the resulting crosslinked materials make them potentially suitable for various applications in paint, coatings, heritage preservation, and medical sector.

Evaluation of biodegradability, toxicity and ecotoxicity of organic acid-based deep eutectic solvents.

Over the past decade, deep eutectic systems (DES) have become popular, yet their potential toxicity to living organisms is not well understood. This study fills this gap by examining the toxicity, antibacterial activity and biodegradability of p-toluenesulfonic acid monohydrate (PTSA)-based DESs prepared from ammonium or phosphonium salts. Brine shrimp assays revealed varying toxicity levels of PTSA and salts. Allyltriphenylphosphonium bromide showing the longest survival time among all tested salts while PTSA exhibited a significantly longer duration of cell survival compared to other hydrogen bond donors. PTSA and ammonium salts (N,N-diethylethanolammonium chloride and choline chloride) as individual components showed non-toxic behavior for Gram-negative and Gram-positive bacteria while different PTSA-based DESs showed significant inhibition zones. Fish acute ecotoxicity tests indicated moderately toxicity for individual components and DESs, though higher concentrations increased fish mortality, highlighting the need for careful handling and disposal of PTSA-based DESs to the environment. Biodegradability analyses found all tested DESs to be readily biodegradable and it was reported that, DES 3 prepapred form PTSA and choline chloride has the highest biodegradability level. Notably, all tested DESs showed over 60 % biodegradability after 28 days. This groundbreaking study explores PTSA-based DESs, highlighting their biodegradability and potential use as antibacterial agents. Results revealed that PTSA as individual component is much better from toxicity point of view in comparison with PTSA-based DESs for any further industrial applications.

Early-life exposure to five biodegradable plastics impairs eye development and visually-mediated behavior through disturbing hypothalamus-pituitary-thyroid (HPT) axis in zebrafish larvae.

Biodegradable plastics have been commonly developed and applied as an alternative to traditional plastics, which cause environmental plastic pollution. However, biodegradable plastics still present limitations such as stringent degradation conditions and slow degradation rate, and may cause harm to the environment and organisms. Consequently, in this study, zebrafish was used to evaluate the effects of five biodegradable microplastics (MPs), polyglycolic acid (PGA), polylactic acid (PLA), polybutylene succinate (PBS), polyhydroxyalkanoate (PHA) and polybutylene adipate terephthalate (PBAT) exposure on the early development, retina morphology, visually-mediated behavior, and thyroid signaling at concentrations of 1 mg/L and 100 mg/L. The results indicated that all MPs induced decreased survival rate, reduced body length, smaller eyes, and smaller heads, affecting the early development of zebrafish larvae. Moreover, the thickness of retinal layers, including inner plexiform layer (IPL), outer nuclear layer (ONL), and retinal ganglion layer (RGL) was decreased, and the expression of key genes related to eye and retinal development was abnormally altered after all MPs exposure. Exposure to PBS and PBAT led to abnormal visually-mediated behavior, indicating likely affected the visual function. All MPs could also cause thyroid system disorders, among which alterations in the thyroid hormone receptors (TRs) genes could affect the retinal development of zebrafish larvae. In summary, biodegradable MPs exhibited eye developmental toxicity and likely impaired the visual function in zebrafish larvae. This provided new evidence for revealing the effects of biodegradable plastics on aquatic organism development and environmental risks to aquatic ecosystems.

Development of a biodegradable prosthesis through tissue engineering, for the organ-replacement or substitution of the extrahepatic bile duct.

INTRODUCTION AND OBJECTIVES: There are different situations in which an extrahepatic bile duct replacement or substitute is needed, such as initial and localized stages of bile duct cancer, agenesis, stenosis, or bile duct disruption. MATERIALS AND METHODS: A prosthesis obtained by electrospinning composed of Poly (D,L-lactide-co-glycolide) (PGLA) - Polycaprolactone (PCL) - Gelatin (Gel) was developed, mechanical and biological tests were carried out to evaluate resistance to tension, biocompatibility, biodegradability, cytotoxicity, morphological analysis and cell culture. The obtained prosthesis was placed in the extrahepatic bile duct of 15 pigs with a 2-year follow-up. Liver function tests and cholangioscopy were evaluated during follow-up. RESULTS: Mechanical and biological evaluations indicate that this scaffold is biocompatible and biodegradable. The prosthesis implanted in the experimental model allowed cell adhesion, migration, and proliferation, maintaining bile duct permeability without altering liver function tests. Immunohistochemical analysis indicates the presence of biliary epithelium. CONCLUSIONS: A tubular scaffold composed of electrospun PGLA-PCL-Gel nanofibers was used for the first time to replace the extrahepatic bile duct in pigs. Mechanical and biological evaluations indicate that this scaffold is biocompatible and biodegradable, making it an excellent candidate for use in bile ducts and potentially in other tissue engineering applications.

Biodegradable Poly (L-Lactic acid) Fibrous Membrane with Ribbon-Structured Fibers and Ultrafine Nanofibers Enhances Air Filtration Performance.

Here, the poly (l-lactic acid) (PLLA) membrane with multi-structured networks (MSN) is successfully prepared by electrospinning technology for the first time. It is composed of micron-sized ribbon-structured fibers and ultrafine nanofibers with a diameter of tens of nanometers, and they are connected to form the new network structure. Thanks to the special fiber morphology and structure, the interception and electrostatic adsorption ability for against atmospheric particulate matter (PM) are significantly enhanced, and the resistance to airflow is reduced due to the "slip effect" caused by ultrafine nanofibers. The PLLA MSN membrane shows excellent filtration performance with ultra-high filtration efficiency (>99.9% for PM2.5 and >99.5% for PM0.3) and ultra-low pressure drop (≈20 Pa). It has demonstrated filtration performance that even exceeds current non-biodegradable polymer materials, laying the foundation for future applications of biodegradable PLLA in the field of air filtration. In addition, this new structure also provides a new idea for optimizing the performance of other polymer materials.

Developmental prospects of carrageenan-based wound dressing films: Unveiling techno-functional properties and freeze-drying technology for the development of absorbent films - A review.

This review explores the intricate wound healing process, emphasizing the critical role of dressing material selection, particularly for chronic wounds with high exudate levels. The aim is to tailor biodegradable dressings for comprehensive healing, focusing on maximizing moisture retention, a vital element for adequate recovery. Researchers are designing advanced wound dressings that enhance techno-functional and bioactive properties, minimizing healing time and ensuring cost-effective care. The study delves into wound dressing materials, highlighting carrageenan biocomposites superior attributes and potential in advancing wound care. Carrageenan's versatility in various biomedical applications demonstrates its potential for tissue repair, bone regeneration, and drug delivery. Ongoing research explores synergistic effects by combining carrageenan with other novel materials, aiming for complete biocompatibility. As innovative solutions emerge, carrageenan-based wound-healing medical devices are poised for global accessibility, addressing challenges associated with the complex wound-healing process. The exceptional physico-mechanical properties of carrageenan make it well-suited for highly exudating wounds, offering a promising avenue to revolutionize wound care through freeze-drying techniques. This thorough approach to evaluating the wound healing effectiveness of carrageenan-based films, particularly emphasizing the development potential of lyophilized films, has the potential to significantly improve the quality of life for patients receiving wound healing treatments.

Microplastic pollution and nutrient enrichment shift the diet of freshwater macroinvertebrates.

Microplastic pollution poses a global threat to freshwater ecosystems, with laboratory experiments indicating potential toxic impacts through chemical toxicity, physical abrasion, and false satiation. Bioplastics have emerged as a potential greener alternative to traditional oil-based plastics. Yet, their environmental effects remain unclear, particularly at scales relevant to the natural environment. Additionally, the interactive impacts of microplastics with other environmental stressors, such as nutrient enrichment, are poorly understood and rarely studied. Under natural conditions organisms might be able to mitigate the toxic effects of microplastics by shifting their diet, but this ability may be compromised by other stressors. This study combines an outdoor mesocosm experiment and stable isotope analysis to determine changes in the trophic niches of three freshwater invertebrate species exposed to conventional (HDPE) and bio-based biodegradable (PLA) microplastics at two concentrations, both independently and combined with nutrient enrichment. Exposure to microplastics altered the isotopic niches of two of the invertebrate species, with nutrient enrichment mediating this effect. Moreover, the effects of microplastics were consistent regardless of their type or concentration. Under enriched conditions, two of the species exposed to microplastics shifted to a specialised diet compared with controls, whereas little difference was observed between the isotopic niches of those exposed to microplastic and controls under ambient nutrient conditions. Additionally, PLA was estimated to support 24 % of the diet of one species, highlighting the potential assimilation of bioplastics by biota and possible implications. Overall, these findings suggest that the toxic effects of microplastics suggested from laboratory studies might not manifest under real-world conditions. However, this study does demonstrate that subtle sublethal effects occur even at environmentally realistic microplastic concentrations. The crucial role of nutrient enrichment in mediating microplastic effects underscores the importance of considering microplastic pollution in the context of other environmental stressors.

The 3-year follow-up of a fully biodegradable implantable device closure for perimembranous ventricular septal defects in children using echocardiography.

Objects: The aim of this study was to investigate the morphologic changes of a novel fully biodegradable implantable device after closing a perimembranous ventricular septal defect (Pm-VSD) and to evaluate the effect of the occluder on the myocardial function in patients during a 3-year follow-up period. Methods: One-year, 2-year, and 3-year follow-ups were carried out after implantation with a total of 30 Pm-VSD patients who had successful closure by the fully biodegradable occluder. In total, 30 healthy children were enrolled as controls. At discharge and at every follow-up visit, the lengths of the left and right discs of the novel device were measured in the apical three- and four-chamber as well as short-axis views. At the end of the follow-up, using three-dimensional speckle-tracking conditions, the values of myocardial deformation, including global longitudinal strain, global circumferential strain, and global area strain, were acquired. Results: The fully bioabsorbable double-disc occluder gradually decreased over time and was eventually invisible under echocardiographic scanning during the follow-up (p < 0.05). At the end of the third year, there were no significant differences in the myocardial deformation parameters between the cases implanted with the novel devices and the controls; no significant differences were found between the basal segments of the ventricle septa and that of the left ventricle (LV) free wall among the patients who completed the Pm-VSD closure using the fully biodegradable occluder (p > 0.05). Conclusion: The novel fully biodegradable occluder is a safe, effective, and perfect alternative for the treatment of VSD. Echocardiography plays a crucial role in the follow-up of this new type of occluder implantation.