Poly Lactic Acid Research Articles

Differentiating low-carbon waste management strategies for bio-based and biodegradable plastics under various energy decarbonization scenarios.

Bio-based and biodegradable (bio-)plastics are heralded as a key solution to mitigate plastic pollution and reduce CO2 emissions. Yet, their end-of-life treatments embodies complex energy and material interactions, potentially leading to emissions through incineration or recycling. This study investigates the cradle-to-grave, emphasizing the waste management stage, carbon footprint for several types of bio-plastics, leveraging both GWP100a and CO2 uptake methods to explore the carbon reduction benefits of recycling over disposal. Our findings indicate that in scenarios characterized by carbon-intensive electricity, using polylactic acid (PLA) as an example, incineration with energy recovery (-1.6316kg CO2-eq/kg, PLA) yields a more favorable carbon footprint compared to chemical recycling (-1.5317kg CO2-eq/kg, PLA). In contrast, in environments with a high proportion of renewable energy, chemical recycling is a superior method, and compared to incineration (-1.4087kg CO2-eq/kg, PLA), the carbon footprint of chemical recycling (-2.0406kg CO2-eq/kg, PLA) are significantly reduced. While mechanical recycling presents considerable environmental benefits, its applicability is constrained by the waste quality, especially in the case of biodegradable plastics like PLA. In addition, the degradation of biodegradable plastics such as PLA was modeled during compost and anaerobic digestion processes. This enables us to quantify the specific biogenic carbon emissions released during these processing steps, revealing the direct emissions with dynamic degradation. This study highlights the importance of tailoring bio-plastic waste management strategies to support global energy decarbonization while understanding their life-cycle carbon metabolism to effectively tackle plastic pollution and climate change.

Influence of biodegradable microplastics on soil carbon cycling: Insights from soil respiration, enzyme activity, carbon use efficiency and microbial community.

The rising prevalence of biodegradable microplastics (BMPs) in soils has raised concerns about their impacts on soil ecosystems and carbon cycling. This study investigates the effects of different BMPs on soil carbon cycling, focusing on soil respiration, enzyme activities, and carbon use efficiency (CUE) from 13C-labeled dissolved organic carbon (DOC) in an upland soil. The BMPs tested were polybutylene adipate terephthalate (PBAT), polyhydroxyalkanoates (PHA), and polylactic acid (PLA), at high (H, 1% w/w) and low (L, 0.1% w/w) concentrations. Over a 64-day incubation, cumulative CO2 emissions increased in the PHA_L, PHA_H, and PLA_H treatments, with the highest rise of 665% PHA_H treatment. Microbial biomass carbon (MBC) ranged from 97.73±3.03mgC kg⁻1 in the control to 223.09±7.91mgC kg⁻1 in PHA_H, with microbial CUE peaking at 0.26 in PHA_H. Enzymatic activities were notably affected: β-glucosidase (BG) increased by 50% in PLA_H, while cellobiohydrolase (CBH) activity decreased by up to 62% in PBAT_H and PLA_L. N-acetylglucosaminidase (NAG) and phosphatase (AP) activities were highest in PHA_H, indicating enhanced nutrient cycling. Microbial community structure based on PLFAs was significantly altered, with total PLFA content increasing by 191% in PHA_H. Correlation analysis and partial least squares path modeling (PLS-PM) revealed that BMP concentration, DOC content, and microbial diversity were positively correlated with microbial CUE. This study highlights the significant role of BMPs in influencing soil carbon cycling, primarily through their effects on microbial diversity and soil enzyme activities.

Biodegradable microplastics adsorb more Cd than conventional microplastic and biofilms enhance their adsorption.

Biodegradable polylactic acid (PLA) mulch has been developed to replace conventional polyethylene (PE) mulch in agriculture to reduce plastic pollution and the accumulation of microplastics (MPs) in soil. Cadmium (Cd) is a significant soil contaminant, and can be adsorbed by MPs. It is increasingly recognised that in the natural environment biofilms can develop on MPs and that this can affect their adsorption properties. We exposed PLA and PE mulches outdoors for 16 months. MPs were then generated from pristine and weathered mulches. Biofilms developed on the weathered plastics. Oxygen-containing functional groups were detected on the weathered, but not the pristine PE, abundance of these groups increased for the weathered PLA. After removal of the biofilm the observed increases in oxygen-containing functional groups relative to the pristine plastics remained. In adsorption experiments pristine PLA MPs had a greater maximum adsorption capacity than pristine PE MPs (106-126 vs 23.2mg/kg) despite having a lower specific surface area (0.325m2/g vs 1.82m2/g) suggesting that the greater levels of adsorption were due to MP chemistry. The weathered plastics adsorbed more Cd than the pristine plastics (e.g. maximum adsorption capacities of 153-185 and 152mg/kg for the weathered PLA and PE respectively). However, after removal of the biofilm, adsorption of Cd to the weathered MPs was no greater than for the pristine plastics. This suggests that the increased adsorption of Cd due to weathering was caused primarily by adsorption onto the biofilm.

Environmental release behavior, cell toxicity and intracellular distribution of novel biodegradable plastic materials.

In response to the increasingly severe issue of plastic waste, biodegradable plastics have garnered extensive attention as a potential alternative to traditional plastics. Among these materials, biodegradable plastics hold a dominant position. The objective of this study was to assess the environmental risks of five commercially available biodegradable plastics: polyglycolic acid (PGA), polylactic acid (PLA), poly(butylene succinate) (PBS), poly(butylene carbonate) (PBC), and poly(butylene adipate-co-terephthalate) (PBAT). The evaluation included their physical properties, microplastic release behavior, and cytotoxicity. In addition, the effect of age process on the environmental behavior of biodegradable plastic materials was further investigated. The results revealed that PGA and PBS exhibited lower risks in terms of microplastic release, whereas PLA demonstrated higher environmental mobility. Further cytotoxicity experiments indicated that PLA and PBS exerted significant toxic effects on human cell lines, including human normal liver cells (LO2), human monocytic leukemia cells (THP-1), human umbilical vein endothelial cells (HUVECs), and human colon carcinoma cells (Caco-2). Additionally, this study utilized Nile Red labeling to observe the co-culture system of PGA with THP-1cells, uncovering that THP-1cells gradually engulfed and internalized PGA microplastics over time. This finding provides new insights into the potential mechanism by which microplastics promote cell proliferation. Moreover, we also found that the aging process partially reduced the cytotoxicity of PGA, but had little effect on environmental mobility. Considering the comprehensive research findings, PGA is considered an ideal material for large-scale applications due to its low cytotoxicity and environmental risks. In contrast, the environmental safety of other types of plastics requires more comprehensive risk assessment to determine their suitability. This study provides significant scientific evidence for the environmental impact assessment of biodegradable plastics and plays a crucial role in promoting the development of sustainable plastic alternatives.

High-efficiency respiratory protection and intelligent monitoring by nanopatterning of electroactive poly(lactic acid) nanofibers.

The advent of multifunctional nanofibrous membranes (NFMs) has led to the development of next-generation air filters that are ready to intercept fine particulate matters (PMs) and monitor the respiratory diseases. However, it is still challenging to fabricate biodegradable NFMs featuring the desirable combination of high filtration efficiencies, low air resistance, and intelligent real-time monitoring. Herein, a hierarchical nanopatterning approach was proposed to functionalize the stereocomplexed poly(lactic acid) (PLA) (SC-PLA) nanofibers via the combined electrospinning of SC-PLA and electrospray of CNT@ZIF-8 nanohybrids. The nanopatterned SC-PLA (NSC-PLA) NFMs were characterized by largely increased surface activity and electroactivity, as evidenced by the nearly two-fold increase in surface potential (up to 7.3kV) and substantial improvements in the dielectric properties. Furthermore, the NSC-PLA NFMs exhibited excellent tribo-output performance, yielding a voltage of as high as 13.5V for NSC-PLA NFMs loaded 10% nanohybrids (NSC-PLA10). In particular, the exceptionally high electroactivity and unique protrusion structure together contributed to promote the filtration efficiencies, while providing a low pressure drop (e.g., 96.1% for PM2.5 and 88.3% for PM0.3, only 67.6Pa of NSC-PLA10, at 32L/min). More importantly, NSC-PLA NFMs enabled real-time monitoring of physiological signals during different respiratory states, as evidenced by the output voltages of 17.2, 32.9 and 37.5mV for normal breath, fast breath and cough recorded by NSC-PLA10. The proposed NSC-PLA NFMs show enormous potential in the fields of air filtration and real-time respiratory monitoring, thus providing ecofriendly solutions to personal health management.

Water triggered injectable polylactic acid hydrogel based on zwitterionic sulfobetaine modification for incompressible bleeding and tissue anti-adhesion.

Massive blood loss is the main cause of prehospital trauma-related death, the development of rapid and effective hemostatic materials is imminent. Injectable hydrogels have the advantages of covering irregular bleeding sites and quickly closing the wound. However, its inherent viscosity can easily precipitate tissue adhesion in vivo and other complications. Based on the anti-protein properties of zwitterion and our previous work about in situ hemostatic/anti-adhesion hydrogel material, we have synthesized a series of injectable hydrogel composed of sulfobetaine-modified polylactic acid (PLA) and gelatin (Gel). These hydrogels could form a smooth film structure by simple water triggering, thereby conferring anti-adhesive properties. We visualized the changes in surface hydrophobicity using fluorescent probes and demonstrated tissue adhesion, rapid hydrophobic interface response, as well as rapid hemostasis for incompressible wounds through in vivo and in vitro experiments. Additionally, we explored the application of hydrogel materials in the scenario of postoperative bleeding, which can effectively prevent unnecessary adhesion through rapid film formation and the anti-protein property of sulfobetaine. We believe that this multifunctional hemostatic hydrogel has the potential to serve as a prehospital emergency treatment of incompressible bleeding and benefit to the postoperative recovery of patients.

Enhanced healing of critical-sized bone defects using degradable scaffolds with tailored composition through immunomodulation and angiogenesis

The impact of orthopedic scaffolds on bone defect healing, particularly the late-stage bone remodeling process, is pivotal for the therapeutic outcome. This study applies fadditively manufactured scaffolds composed of hydroxyapatite-doped poly(lactide-co-glycolide)-b-poly(ethylene glycol)-b-poly(lactide-co-glycolide) (HA-PELGA) with varying properties to treat rat calvarial defects, elucidating their significant role in bone remodeling by modulating physiological responses. We engineered two scaffolds with different polylactic acid (PLA) to polyglycolic acid (PGA) ratio (9/1 and 18/1) to vary in hydrophobicity, degradation rate, mechanical properties, and structural stability. These variations influenced physiological responses, including osteogenesis, angiogenesis, and immune reactions, thereby guiding bone remodeling. Our findings show that the HA-PELGA(18/1) scaffold, with a slower degradation rate, supported bulk bone formation due to a stable microenvironment. Conversely, the HA-PELGA(9/1) scaffold, with a faster degradation rate and more active interfaces, facilitated the formation of a thin bone layer and higher bone infiltration. This study demonstrates these degradable scaffolds help to promote bone healing and reveals how scaffold properties influence the bone remodeling process, offering a potential strategy to optimize scaffold design aiming at late-stage bone defect healing.

Attapulgite microspheres coated with poly(lactic acid-glycolic acid) nanoparticles form satellite structure to enhance doxorubicin delivery in bone cancer therapy

Attapulgite microspheres coated with poly(lactic acid-glycolic acid) nanoparticles form satellite structure to enhance doxorubicin delivery in bone cancer therapy

The role of photooxidation and organic matter in Cr(III) and Cr(VI) interactions with poly(lactic acid) microplastics in aqueous solution

The role of photooxidation and organic matter in Cr(III) and Cr(VI) interactions with poly(lactic acid) microplastics in aqueous solution

Epoxidized safflower oil: Synthesis and evaluation of its performance as bioplasticizer for polylactic acid films

Epoxidized safflower oil: Synthesis and evaluation of its performance as bioplasticizer for polylactic acid films

Curcumin derivative intercalated expandable graphite: Imparting flame retardancy, anti-dripping and smoke suppression for polylactic acid composites

Curcumin derivative intercalated expandable graphite: Imparting flame retardancy, anti-dripping and smoke suppression for polylactic acid composites

Polylactic acid microplastics induced negative priming and improved carbon sequestration via microbial processes in different paddy soils

Polylactic acid microplastics induced negative priming and improved carbon sequestration via microbial processes in different paddy soils

Process performance of in-situ bio-methanation for co-digestion of sewage sludge and lactic acid, aiming to utilize waste poly-lactic acid as methane

This study examined hydrogen conversion efficiency and operational stability in pilot-scale in-situ bio-methanation during the co-digestion of sewage sludge and lactic acid (partially derived from waste poly-lactic acid). Parallel laboratory-scale experiments were also conducted. In the pilot, hydrogen conversion efficiency decreased from 98.9 % to 84.4 % as the hydrogen feed rate increased from 240 to 1,200 mL/LR/d. Conversely, laboratory experiments maintained efficiencies above 95 % at a feed rate of 3,600 mL/LR/d, suggesting that hydrogen gas–liquid transfer limited hydrogen conversion efficiency in the pilot. Lactic acid degradation was observed both with and without hydrogen injection in the pilot. Methane yields from the acid were 310 ± 30 and 300 ± 30 mL/g (chemical oxygen demand (COD))-added, close to the theoretical methane yield (350 mL/gCOD). These results demonstrate the importance of hydrogen gas–liquid transfer when scaling up bio-methanation processes. Moreover, they showed the potential of waste poly-lactic acid as a methane source.

Characterizing Phosphorus Removal and Recovery Performance of a 3D Printed Iron-Embedded Polylactic Acid Composite

Characterizing Phosphorus Removal and Recovery Performance of a 3D Printed Iron-Embedded Polylactic Acid Composite

Effects of degradable and non-degradable microplastics on SPNEDPR-AGS system: Sludge characteristics, nutrient transformation, key enzyme, and microbial community

The environmental risk of microplastics (MPs) in aerobic granular sludge (AGS) system is unclear. This study evaluates the effects of non-biodegradable polyvinyl chloride microplastics (PVC-MPs) and biodegradable polylactic acid microplastics (PLA-MPs) on AGS systems. The results showed that both destroyed the performance of AGS systems, with PVC-MPs achieving this by disrupting the AGS structure, while PLA-MPs mainly by causing the expansion of filamentous bacteria induced through the stimulation by lactic acid metabolite (R0: 5.52 ± 0.49 μg/L; RPLA5: 11.67 ± 0.56 μg/L). Moreover, both MPs inhibited nitrogen removal by disrupting partial nitrification and endogenous denitrification and suppressed key microbes such as Candidatus Competibacter and Nitrosomonas. Metabolic pathway analysis and molecular docking have further confirmed the mechanisms by which MPs affect critical metabolic pathways and key enzymes. Consequently, the hazards of biodegradable MPs to the stable operation of sewage treatment plants should also be of concern.

3D bioprinted poly(lactic acid) scaffolds infused with curcumin-loaded nanostructured lipid carriers: a promising approach for skin regeneration.

Nanotechnology and 3D bioprinted scaffolds are revolutionizing the field of wound healing and skin regeneration. By facilitating proper cellular movement and providing a customizable structure that replicates the extracellular matrix, such technologies not only expedite the healing process but also ensure the seamless integration of new skin layers, enhancing tissue repair and promoting overall cell growth. This study centres on the creation and assessment of a nanostructured lipid carrier containing curcumin (CNLC), which is integrated into a 3D bioprinted PLA scaffold system. The goal is to investigate its potential as a vehicle for delivering poorly soluble curcumin for enhanced wound healing. The developed CNLC exhibited an oval morphology and average particle size of 292 nm. The entrapment efficiency (EE) was 81.37 ± 0.85%, and the drug loading capacity was 6.59 ± 1.61%. CNLC was then integrated into PLA-based 3D bioprinted scaffolds, and physicochemical analyses were conducted to evaluate their properties. Cell viability studies carried out using fibroblast cells demonstrated that the PLA/CNLC scaffolds are non-cytotoxic. In vivo experiments showed that the PLA/CNLC scaffolds exhibited complete wound contraction and closure of full-thickness wounds within a period of 21 days. The findings confirmed the scaffold's capacity as a tool for accelerating wound healing. The research emphasises the need for using biomimetic 3D printed scaffold materials and the promise of nanobiotechnology in enhancing treatment efficacy.

Toughening Poly(lactic acid) without Compromise - Statistical Copolymerization with a Bioderived Bicyclic Lactone.

Poly(lactic acid) (PLA) offers a renewable and degradable alternative to petroleum-based plastic, but its mechanical properties are not ideal for many applications. Herein, we describe the synthesis and polymerization of 2-oxo-3,8-dioxabicyclo[3.2.1]octane (ODO), a bioderived bicyclic lactone, and show that copolymers of l-lactide (LA) with small amounts of ODO have improved mechanical properties over PLA. Homopolymerization of ODO to poly(oxo-3,8-dioxabicyclo[3.2.1]octane) (PODO) is optimized for both solution-phase, organocatalytic and melt-phase, metal-catalyzed conditions. In comparison to the monocyclic analog, ε-caprolactone (CL), ODO has a lower enthalpy of polymerization and faster rate of polymerization. PODO is an amorphous, elastomeric polyester that has a Tg 90 °C higher than poly(ε-caprolactone) (PCL). Statistical copolymerization of LA with small fractions of ODO yields tough and transparent thermoplastics that have over 12× elongation at break compared to native PLA, while maintaining Tg, Young's modulus (E), and yield strength. Together, these results describe how the incorporation of the tetrahydrofuran ring alters lactone polymerizability and the thermomechanical properties of the homopolymer and copolymer materials.

The Effect of Applying Treatment Sludge and Vermicompost to Soil on the Biodegradability of Poly(lactic acid) and Poly(3-Hydroxybutyrate)

The Effect of Applying Treatment Sludge and Vermicompost to Soil on the Biodegradability of Poly(lactic acid) and Poly(3-Hydroxybutyrate)

High energy radiation induced degradation of poly(lactic acid) (PLLA) film: radiation chemical yield, kinetics, mechanism and radioracemization evidences

High energy radiation induced degradation of poly(lactic acid) (PLLA) film: radiation chemical yield, kinetics, mechanism and radioracemization evidences

Polylactic Acid Micro/Nanoplastic Exposure Induces Male Reproductive Toxicity by Disrupting Spermatogenesis and Mitochondrial Dysfunction in Mice.

Although considered an "eco-friendly" biodegradable plastic, polylactic acid (PLA) microplastic (PLA-MP) poses a growing concern for human health, yet its effects on male reproductive function remain underexplored. This study investigated the reproductive toxicity of PLA in male mice and its potential mechanisms. To this end, our in vivo and in vitro experiments demonstrated that after degradation in the digestive system, a significant number of PLA-MP-derived nanoparticles could penetrate the blood-testis barrier (BTB) and localize within the spermatogenic microenvironment. Mice exposed to PLA-MPs for a long time exhibited significant reproductive toxicity, evidenced by decreased sperm concentration and motility, increased sperm deformity rates, and disrupted sex hormone levels. Further analysis revealed that PLA impaired BTB, induced mitochondrial dysfunction in the testes, and triggered oxidative stress through excessive ROS production from mitochondria, leading to further testicular damage. Notably, PLA nanoplastics internalized in the mitochondrial sheath and disrupted the mitochondrial structure of sperm, causing dose-dependent impairments in mitochondrial function. Transcriptome analyses further indicated that PLA-MPs disrupted spermatogenesis by inhibiting the expression of key mRNA involved in this process. Collectively, our findings highlight the reproductive toxic effect of biodegradable PLA by damaging BTB and impairing mitochondrial function, which provides insights into the toxicological implications of biodegradable microplastics for mammalian fertility.