Hydrolytic Degradation Research Articles

Biodegradable PLA films incorporating GO‐ZnO hybrid and Mentha Longifolia oil: Fabrication and characterization

AbstractThe study investigates the effects of graphene oxide/zinc oxide (GO‐ZnO) nanohybrids, combined with Mentha longifolia essential oil, on the mechanical, UV resistance, antibacterial, and rheological properties of polylactic acid (PLA). GO‐ZnO nanohybrids were prepared at ZnO‐to‐GO ratios of 1:1 and 2:1 and incorporated into PLA at various concentrations. The addition of GO‐ZnO significantly enhanced the tensile strength and modulus of PLA composites due to strong interactions between PLA and the functionalized nanohybrids. Hydrolytic degradation tests revealed accelerated PLA degradation with GO‐ZnO, attributed to the catalytic effects of ZnO. Rheological analysis showed reduced elasticity with higher nanohybrid content, attributed to thermal degradation. UV absorption tests demonstrated improved UV protection with GO‐ZnO and essential oil. Antibacterial tests indicated higher inhibition percentages against E. coli and Listeria, highlighting a synergistic antibacterial effect of the hybrid system. These findings suggest PLA/GO‐ZnO/oil composites are promising candidates for antibacterial packaging applications.Highlights PLA hydrolytic degradation enhanced by GO‐ZnO nanohybrids, M. longifolia oil. GO‐ZnO and M. longifolia oil catalyze PLA thermal degradation during scission. PBS mechanical properties improved via GO‐ZnO interaction with PLA and oil. GO‐ZnO and M. longifolia oil provide synergistic antibacterial effects in PLA. Thermal degradation of PLA with GO‐ZnO and oil analyzed through rheology.

Structural features of dioxane lignin: A comparative study with milled wood and formaldehyde-stabilized lignins.

Dioxane lignin (DL) is isolated from plant material under mild acidolysis conditions and is widely used in many studies as a representative sample of protolignin, an alternative to milled wood lignin (MWL). However, the structural changes caused by hydrolytic degradation reactions during DL extraction are still poorly understood. In this work, an integrated approach based on 2D NMR and high-resolution mass spectrometry was used to establish the features of the lignin structure on the example of pine lignin isolated using dioxane under various conditions: MWL, DL and "formaldehyde stabilized" lignin (LSF). In this context, we sought to gain a deeper understanding of the chemical structure of DL, focusing on the least studied fragments. Cross-peaks related to the degradation products of 1,2-diarylpropane were uniquely identified for the first time by a combination of HSQC-HMBC spectra. In addition, the 1,3-dioxane structure of β-aryl ether, the presence of which in DL has not been previously observed and originates from elements of the native structure and formaldehyde (product of lignin destruction), was unambiguously shown and confirmed by NMR and mass spectrometry analysis. Additionally, signals related to the 1,3-dioxane structure of 1,2-diarylpropane were also detected for the first time in the HSQC spectrum of LSF.

HEMA-free versus HEMA-containing adhesive systems: a systematic review

BackgroundHydrophilic monomer 2-hydroxyethyl methacrylate (HEMA)-free adhesive systems are gaining increasing popularity nowadays. Although the addition of HEMA to dental adhesives improves dentin wettability and resin diffusion into demineralized collagen fibrils, HEMA’s high hydrophilicity can lead to hydrolytic degradation of the adhesive interface. Thus, HEMA-free adhesive systems have been developed. Unfortunately, the lack of HEMA in the adhesive composition may lead to a separation phase between hydrophobic and hydrophilic components. The aim of this systematic review was to evaluate the clinical performance of HEMA-free adhesive systems and compare them with HEMA-containing ones.MethodsAn electronic search of The National Library of Medicine (MEDLINE/PubMed) was conducted. Eligibility criteria were reporting empirical data from clinical studies published between 2013 and 2023 about the clinical performance of HEMA-free adhesive systems for direct resin composite restorations. Studies with at least 2-year clinical follow-up done in permanent dentition in any form of cavities were selected. The included studies were assessed for risk of bias using the modified Cochrane Collaboration tool criteria.ResultsThe database search returned 147 studies; a total of 7 studies were included in this review; the majority of studies reported no significant difference between the two types of adhesives for the parameter of retention.ConclusionsHEMA-free adhesive systems exhibited good clinical performance with regard to retention. There was some concern about their influence on marginal adaptation and marginal discoloration due to the conflicted results reported by the included trials. Thus, the results need to be confirmed with long-term evaluations.Systematic review registrationPROSPERO CRD42023448952.

Role of Copper and Zinc Ions in the Hydrolytic Degradation of Neurodegeneration-Related Peptides.

Spontaneous cleavage reactions normally occur in vivo on amino acid peptide backbones, leading to fragmentation products that can have different physiological roles and toxicity, particularly when the substrate of the hydrolytic processes are neuronal peptides and proteins highly related to neurodegeneration. We report a hydrolytic study performed with the HPLC-MS technique at different temperatures (4 °C and 37 °C) on peptide fragments of different neuronal proteins (amyloid-β, tau, and α-synuclein) in physiological conditions in the presence of Cu2+ and Zn2+ ions, two metal ions found at millimolar concentrations in amyloid plaques. The coordination of these metal ions with these peptides significantly protects their backbones toward hydrolytic degradation, preserving the entire sequences over two weeks in solution, while the free peptides in the same buffer are fully fragmented after the same or even shorter incubation period. Our data show that peptide cleavage is not only ruled by the chemical sensitivity of amino acids, but the peptide conformation changes induced by metal coordination influence hydrolytic reactions. The enhanced stability of neuronal peptides provided by metal coordination can increase local levels of amyloidogenic species capable of seeding fibril growth, resulting in aberrant protein depositions and deficits in neuronal activity.

Investigation of the Thermal Stability and Hydrolytic Degradation Kinetics of Poly(Lactide-co-Glycolide) Melts.

Poly(lactide-co-glycolide) (PLGA) is widely used in a variety of long-acting injectables. However, its biodegradable nature creates potential chemical stability challenges during melt extrusion, where PLGA is exposed to elevated temperature (100-140°C) for several minutes. This study evaluated the thermal stability of three PLGA grades (Resomer® 502, 502H, and 505) with varying molecular weights and chain-ends using a differential scanning calorimeter and twin-screw extruder. DSC results revealed that both residual water content and chain-end groups significantly accelerate PLGA degradation. At 0.2% water content, all samples maintained good stability (less than 15% reduction in molecular weight). However, at 0.4% water content, Resomer 502H, which has acid end groups, experienced significant degradation (45% reduction in molecular weight) after 30min at 140°C due to catalyzed hydrolysis. The extruded samples remained stable across tested barrel temperatures (100°C and 140°C) and screw speeds (125 and 250rpm). Further investigations of PLGA with 0.2% water content demonstrates that the hydrolysis rates of Resomer® 502 and 505 were comparable, indicating that molecular weight does not influence hydrolysis rate. In contrast, Resomer® 502H exhibited a higher hydrolysis rate and a slightly higher activation energy, suggesting a greater temperature dependency. Additionally, when subjected to 200°C for one hour with less than 0.03% water content, Resomer® 505 showed a less than 7% reduction in molecular weight, indicating minimal thermal degradation. Conversely, Resomer® 502 and 502H experienced an increase in molecular weight, which was likely attributed to recombination reactions, particularly in Resomer® 502H, which has higher tin content (170ppm).

Identification of ketamine and norketamine in dried bloodstains on crime-scene surfaces

BackgroundToxicological analysis of dried bloodstains (DBS) provides critical information for reconstructing the sequence of events at a crime scene. Drugs have higher stability in DBS relative to liquid blood owing to the arrest of enzymatic reactions in dehydrated samples. However, literature on the identification of ketamine and its metabolites in DBS is limited and is mostly focussed on the analysis of bloodstains collected on paper cards. The present study has analysed the stability of ketamine and norketamine in DBS aged on common crime scene surfaces under various storage temperatures. Coloured linen fabric and glass slide, representing porous and non-porous surfaces, respectively, were stained with a defined volume of drug-fortified whole blood and stored at room temperature (20 °C), in the refrigerator (4 °C), and freezer (− 20 °C) for 1, 7, and 14 days. Analytes were solvent-extracted using a dichloromethane: hexane (1:3 v/v) mixture, followed by gas chromatography-mass spectrometry (GC–MS) analysis with ketamine-d4 as the internal standard.ResultsAt least 4.3 ng/mL and 8.7 ng/mL ketamine and norketamine, respectively, were detected in dried stains prepared from 5 to 50 µL whole blood corresponding to a concentration range of 10–100 ng/mL. The GC–MS method was linear in this range with a coefficient of determination, R2 > 0.99. Recovery of the analytes was comparable (~ 100–120%) between DBS porous and whole blood, whereas it was considerably lower (~ 50%) in DBS non-porous samples due to the incomplete transfer of the stains from the glass into the extraction solvent mixture. Analyte response in DBS showed a strong correlation with that in whole blood at four concentration levels (0.1–5 µg/mL). Mean precision values (% CV) for biological and technical replicates (n = 5) were 15.0 and 6.5, respectively, and within an acceptable range.ConclusionsThe developed method for the analysis of ketamine and norketamine in DBS is comparable to that in other biological matrices such as whole blood under short-term storage conditions. Lower temperatures are favourable for maintaining the integrity of the samples; however, the bloodstains must be completely dried before storing them in the refrigerator or freezer for short-term (1–7 days) to prevent hydrolytic degradation of drugs.Graphical

A multi-residue method based on solid phase extraction followed by HPLC-HRMS/MS analysis for the determination of dyes and additives released from polyester fibres after degradation.

Microfibres released from textiles are one of the most common types of microplastics (MPs) found in the environment. Whether they are synthetic or natural, they can undergo degradation in different environmental matrices. This may result in the leaching of a variety of chemicals, mainly textile dyes and additives of high toxicity that need to be regulated. A novel method was developed, validated and applied to identify and quantify these types of compounds present in a hydrolytic alkaline degradation solution (neutralized), but it can also be used in similar laboratory-simulated solutions, and seawater. The employed solution was utilized in an accelerated degradation simulation of two different polyester (PES) fibre types. Thirteen compounds were extracted and quantified using a solid-phase extraction protocol followed by HPLC-HRMS/MS. Intra-day (Intra-R) and inter-day (Inter-R) precision ranged from 0.02 to 6.23 % and 0.08 to 8.85 %, respectively, while linearity (R2) values were >0.9980. The limits of detection (LOD=0.7- 3.3 ng mL-1) and quantification (LOQ=0.5- 10 ng mL-1) were determined for the proposed method. Good recoveries were obtained for all compounds studied (65-120 %), while matrix effects ranged from -6 to 30 %, depending on the analyte. Ten compounds were detected and quantified in the degradation solution of the two different polyester fibres, with three (benzothiazole, 4-nitrophenol, 2,6-dichloro-4-nitroaniline) being PES type specific, while the rest were found in both types. A non-target analysis allowed the identification of a wider range of possible leachates (55 compounds in positive ion mode and 24 in negative).

Oxygen vacancies boost the efficacy of MnO2 nanoparticles in catalyzing the hydrolytic degradation of organophosphate esters: implications for managing plastic additive pollution

Oxygen vacancies enhance the efficiency of α-MnO2 nanoparticles in catalyzing the hydrolysis of 4-nitrophenyl phosphate (pNPP), a model organophosphate pollutant.

In situ synthesis of degradable polymer prodrug nanoparticles.

The in situ synthesis of degradable polymer prodrug nanoparticles is still a challenge to be met, which would make it possible to remedy both the shortcomings of traditional formulation of preformed polymers (e.g., low nanoparticle concentrations) and those of the physical encapsulation of drugs (e.g., burst release and poor drug loadings). Herein, through the combination of radical ring-opening polymerization (rROP) and polymerization-induced self-assembly (PISA) under appropriate experimental conditions, we report the successful preparation of high-solid content, degradable polymer prodrug nanoparticles, exhibiting multiple drug moieties covalently linked to a degradable vinyl copolymer backbone. Such a rROPISA process relied on the chain extension of a biocompatible poly(ethylene glycol)-based solvophilic block with a mixture of lauryl methacrylate (LMA), cyclic ketene acetal (CKA) and drug-bearing methacrylic esters by reversible addition fragmentation chain transfer (RAFT) copolymerization at 20 wt% solid content. This novel approach was exemplified with two different CKA monomers and two different anticancer drugs, namely paclitaxel and gemcitabine, to demonstrate its versatility. After transferring to water, remarkably stable aqueous suspensions of core-degradable polymer prodrug nanoparticles, 56-225 nm in diameter, with tunable amounts of CKA units (7-26 mol%) and drug loadings of up to 33 wt% were obtained. The incorporation of ester groups in the copolymers was demonstrated by hydrolytic degradation of both the copolymers and the nanoparticles under accelerated conditions. The nanoparticles showed significant cytotoxicity against A549 cells, used as a lung cancer model. Fluorescence labeling of the solvophilic block also enabled effective monitoring of cell internalization by confocal microscopy, with potential for theranostic applications.

Hybrid Hydrogel Supplemented with Algal Polysaccharide for Potential Use in Biomedical Applications.

Hydrogels are a viable option for biomedical applications due to their biocompatibility, biodegradability, and ability to incorporate various healing agents while maintaining their biological efficacy. This study focused on the preparation and characterization of novel hybrid hydrogels enriched with the natural algae compound Ulvan for potential use in wound dressings. The characterization of the hydrogel membranes involved multiple methods to assess their structural, mechanical, and chemical properties, such as pH measurements, swelling, moisture content and uptake, gel fraction, hydrolytic degradation, protein adsorption and denaturation tests, rheological measurements, SEM, biocompatibility testing, and scratch wound assay. The hydrogel obtained with a higher concentration of Ulvan (1 mg/mL) exhibited superior mechanical properties, a swelling index of 264%, a water content of 55%, and a lower degradation percentage. In terms of rheological properties, the inclusion of ULV in the hydrogel composition enhanced gel strength, and the Alginate + PVA + 1.0ULV sample demonstrated the greatest resistance to deformation. All hydrogels exhibited good biocompatibility, with cell viability above 70% and no obvious morphological modifications. The addition of Ulvan potentiates the regenerative effect of hydrogel membranes. Subsequent studies will focus on encapsulating bioactive compounds, investigating their release behavior, and evaluating their active biological effects.

Optimizing conditions for carbofuran degrading isolates: a pathway to sustainable bioremediation in agricultural settings

Agriculture, driven by the escalating global demand for food, heavily relies on pesticides to ensure high yields and pest-free produce. The carbamate group of pesticides, including the widely used carbofuran, presents advantages such as low retention, high efficacy, and broad application. However, the associated health concerns categorize these pesticides as hidden threats. In response, biological remediation emerges as a more cost-efficient and environmentally friendly alternative to chemical or physical approaches. Our prior investigation identified 17 highly potential carbofuran degraders, forming the basis for this research. The focus lies on optimizing the isolates’ growth conditions, exploring temperatures (30 °C and 37 °C) and pH levels (7 and 9) in Bushnell Haas Agar. It was observed that all four pesticide doses (250, 500, 750, and 1000 mg/L) in Bushnell Haas Agar medium were supported by the majority of isolates at 30 °C and pH 9, whereas 750 and 1000 mg/L were favored at pH 7 (30 °C) and at both pH 7 and 9 (37 °C). Despite limited biofilm-forming ability rendered due to presence of ompA along with or with not bap gene, the isolates’ extracellular polymeric substance (EPS) composition indicated a polymeric nature. Also 13 of the isolates’ EPS production accelerates at 250 mg/L pesticide concentration. Metabolic pathway analyses revealed a preference for hydrolytic degradation, while molecular examinations confirmed the presence of plasmid and the absence of specific genes mcd and cehA responsible for carbamate – hydrolase on the chromosome. Concern is raised by the presence of colistin and tetracycline resistant genes (mcr2 (47.05%), tetA (29.41%), and qnrs (23.53%) in the genomic content of some isolates, in addition to ESBL resistance genes found in varying frequencies, such as blaIMP3 (5.89%), blaVIM (70.59%), blaKPC (88.25%), blaOXA-1 (11.76%), bla-SHV (23.53%) & blaOXA1 (11.76%), bla-CTMX15 (17.65%), necessitating alternative mechanisms. The findings demonstrate the isolates’ dual function as repositories of antibiotic resistance and prospective bioremediation agents, requiring careful handling and application. Developing safe and efficient bioremediation systems will need addressing resistance issues while maximizing degrading efficiency.

Natural Molecule-Derived Nanogels from Hematoxylin and l-lysine for Biomedical Use with Antimicrobial Properties.

Hematoxylin (HT) is a natural staining dye used in histopathology, often combined with Eosin for H&E staining. A poly(hematoxylin-co-l-lysine) (p(HT-co-l)) nanonetwork was synthesized through a one-step Mannich condensation reaction using formaldehyde as a linking agent. The resulting p(HT-co-l) nanogels had an average size of about 200 nm and exhibited a smooth surface and desirable functional groups such as -OH, -NH2, and -COOH, as recognized by FT-IR analysis. The isoelectric point (IEP) of the p(HT-co-l) nanogel was determined as pH 7.9, close to physiological environments, despite HT being acidic IEP at pH 1.7 and l-lysine being basic IPE at pH 8.7. The time-dependent swelling studies of p(HT-co-l) nanogels were carried out using dynamic light scattering (DLS) in different salt solutions, e.g., MgCl2, KNO3, KCl, PBS, and DI water environments revealed that nanogels have high swelling ability depending on the medium, e.g., >10-fold in a saline solution compared to distilled water within 1.5 h. Hydrolytic degradation studies in PBS demonstrated a linear release profile up to 125 h at 37.5 °C. The p(HT-co-l) nanogels also demonstrated significant antimicrobial and antifungal activities against E. coli (ATCC 8739), S. aureus (ATCC 6538), and C. albicans (ATCC 10231). Furthermore, biocompatibility tests indicated that p(HT-co-l) nanogels are more biocompatible than HT alone, as tested with human Nuli-1 bronchial epithelial cells.

Poly(3-hydroxybutyrate) Modified with Thermoplastic Polyurethane and Microfibrillated Cellulose: Hydrolytic Degradation and Thermal and Mechanical Properties.

Blending poly(3-hydroxybutyrate) (PHB) with other polymers could be a rapid and accessible solution to overcome some of its drawbacks. In this work, PHB was modified with microfibrillated cellulose (MC) and a thermoplastic polyurethane containing biodegradable segments (PU) by two routes, using a masterbatch and by direct mixing. The PU and MC modifiers improved the thermal stability of PHB by up to 13 °C and slightly decreased its melt viscosity and crystallinity, thus improving the melt processability. The addition of PU in PHB composites led to a decrease in the storage modulus, which did not exceed 20% at room temperature. The hydrolytic degradation in an alkaline environment at 50 °C for 28 days decreased the thermal stability of the composites by 58-65 °C, while the lower mass loss and morphological features showed that the PU modifier delayed the degradation of the PHB composites. The improved thermal stability, melt processability, and lower cost, along with higher flexibility and the possibility of controlling the hydrolytic degradation by the PU content, make the PHB/PU/MC composites obtained by the masterbatch method promising materials for medical and engineering applications.

Rapid and well-controlled degradation of polylactic acid materials with bio-based GEL(pectin/α-cellulose/SiO2/CaCl2).

Polylactic acid (PLA) has been a subject of considerable interest as a degradable polymer. However, the degradation process is slow and uncontrollable. In this work, controlled degradable PLA/bio-based GEL (pectin/α-cellulose/SiO2/CaCl2) hydrophilic plasticizer composite material was successfully prepared by solution blending process. The bio-based GEL was proven to have strong water absorption properties and the ability to improve and regulate the degradation performance of PLA. The results declared that the addition of 5% GEL and 15% polyethylene glycol (PEG) to the PLA composites resulted in a degradation degree of 83% within 12h in an alkaline solution. And the rate represents a 21.2-fold increase in speed compared to pure PLA material. Under neutral and acidic conditions, the degradation degree of the modified composites was approximately 169 times faster than that of pure PLA. Meanwhile, the tensile strength of PLA composites decreased from 44.8MPa to 16.7MPa, but the elongation at break increased from 5.8% to 172% compared to pure PLA. Furthermore, the initial decomposition temperature and maximum thermal decomposition rate temperature of PLA composites were found to be reduced. The controlled degradation of PLA composites was accomplished through the regulation of GEL content. The hydrolysis degradation process under different pH laid a foundation for the pretreatment process of soil microbial degradation of PLA. The mechanism suggested that the GEL created a large number of pores on the surface and inside the material within an extremely short period of time, providing ample opportunities for soil microorganisms to invade.

Enhanced antioxidant and antimicrobial activities of chitosan/oxidized microcrystalline cellulose blended films with Tribulus terrestris extract for food packaging applications.

Chitosan/oxidized cellulose blended film with Tribulus terrestris (T. terrestris) extract films were successfully produced by casting method. The obtained blend films were characterized by structural, mechanical, optical, permeation, antioxidant, and antimicrobial properties. Finally, these biodegradable blend films were used to prolong the shelf-life of sour cherries. Remarkable physical properties such as water vapor transmission rate, swelling, water solubility, mechanic strength, and UV-vis light transmittance were observed to improve positively. All blend films showed 60-70 % degradation after 30 days of hydrolytic degradation and soil burial. T. terrestris extract increased the tensile strength from 1.1 MPa to a maximum of 2.1 MPa and elongation at break from 16 % to 46 %. Furthermore, blend films with T. terrestris extract showed ~4 and ~ 3.7 times higher ABTS•+ and DPPH• scavenging potential, respectively. Moreover, the findings also revealed that blend films displayed strong antimicrobial activity against S. aureus, E. coli, and C. tropicalis. Most importantly, the shelf life of sour cherries packaged with blend films was effectively extended up to 10 days. Overall, blended films are a promising potential alternative material to petroleum-based synthetic plastics for use in active food packaging, especially in products with short shelf life such as sour cherry.

Mitophagy in Doxorubicin-Induced Cardiotoxicity: Insights into Molecular Biology and Novel Therapeutic Strategies.

Doxorubicin is a chemotherapeutic drug utilized for solid tumors and hematologic malignancies, but its clinical application is hampered by life-threatening cardiotoxicity, including cardiac dilation and heart failure. Mitophagy, a cargo-specific form of autophagy, is specifically used to eliminate damaged mitochondria in autophagosomes through hydrolytic degradation following fusion with lysosomes. Recent advances have unveiled a major role for defective mitophagy in the etiology of DOX-induced cardiotoxicity. Moreover, specific interventions targeting this mechanism to preserve mitochondrial function have emerged as potential therapeutic strategies to attenuate DOX-induced cardiotoxicity. However, clinical translation is challenging because of the unclear mechanisms of action and the potential for pharmacological adverse effects. This review aims to offer fresh perspectives on the role of mitophagy in the development of DOX-induced cardiotoxicity and investigate potential therapeutic strategies that focus on this mechanism to improve clinical management.

Site-specific weathering of coatings: II. Comparison of natural weathering and accelerated protocols for Central Europe and Florida

AbstractWeathering protocols, which anticipate exposure behavior of coatings in the temperate climate in Central Europe (ZykStuttgart: ZS) and Florida (new protocol: NP), were applied for accelerated testing of melamine-, silicone resin/acrylate dispersion-, and polyurethane-based coating systems and compared to natural weathering at related sites in Stuttgart (Germany) and near Homestead (Florida/USA), respectively. Color parameters and infrared spectra were measured after defined exposure times and normalized to the irradiation doses. Color changes of an industrial standard with an orange pigment (ORWET) were found to depend for both artificial and natural weathering tests predominantly on irradiation dose. This confirms that the spectral power distribution of the lamp/filter configuration proposed in NP matches sufficiently well to both the sunlight spectra in Florida and Stuttgart. For a melamine-based standard crack coat, crack initiation was found only for NP and the late stage of ZS. For all coating systems studied, characteristic band intensities of infrared spectra and/or color parameters for the two protocols and from natural weathering at the related outdoor sites were shifted along the time axis to merge to master plots. To differentiate between thermally activated, photo-initiated, and hydrolytic degradation, the shift factors were plotted versus inverse annual- or cycle-averaged temperatures including irradiation ratios and averaged humidity ratios. Despite the different reaction mechanism for the acrylic component in the silicone resin/acrylate and the polyurethane coating, a dominance of thermally activated degradation was evident for both. The melamine-based binder showed coupled degradation mechanisms (photo-induced and thermally activated complimented by moisture effects). The use of irradiation doses, cycle-, and annual-averaged temperatures together with cycle- and annual-averaged humidities for data analysis provided simple possibilities for comparison of protocols and weathering sites and a rough differentiation between degradation mechanisms.

Composites Based on PLA/PHBV Blends with Nanocrystalline Cellulose NCC: Mechanical and Thermal Investigation.

This study investigates the physical and mechanical properties of biodegradable composites based on PLA/PHBV blends modified with different content of nanocrystalline cellulose (NCC) of 5, 10, and 15 wt.%. Density measurements reveal that the density of the composite increases with increasing NCC content. Water absorption tests demonstrate a gradual increase in the composite water content with increasing incubation time, reaching stabilization after approximately 30 days. Mechanical testing was also carried out on both on conditioned samples after the process of hydrolytic degradation and accelerated thermal aging. The conditioned composites show an increase in the stiffness of the materials with increasing content of nanocrystalline cellulose. The ability to deform and the ability to absorb energy when the sample is dynamically loaded decrease. The repeated strength tests, after the process of incubation of samples in water and after the process of accelerated thermal aging, show the degradation of composite materials; however, it is noticed that the introduction of cellulose addition reduces the impact of the applied artificial environment in aging tests. The findings of this study indicate promising applications for these types of materials, characterized by high strength and biodegradability under appropriate conditions. Household items such as various containers or reusable packaging represent potential applications of these composites.

Super Porous Carboxymethyl Cellulose–Tannic Acid (TA@CMC) Cryogels with Antioxidant, Antibacterial, and α-Glucosidase Enzyme Inhibition Abilities

Here, super porous carboxymethyl cellulose (CMC) cryogels were synthesized in 10–100% crosslinker and the presence of TA, at varying amounts of TA, e.g., 10 and 25 wt% of CMC under cryogenic conditions (−20 °C) as TA@CMCs. To control the degradation of CMC cryogel networks, the crosslinking ratio of divinyl sulfone (DVS:X) to CMC varied at 10, 25, 50, and 100% moles of the CMC repeating unit. Higher hydrolytic degradation was observed for CMC 10%X cryogels at pH 1.0 with 28.4 ± 1.2% weight loss. On the other hand, the TA-release studies from TA@CMC-based cryogels showed that higher TA releases were observed for both TA@CMC 10% and 25% cryogels at pH 7.4, with 23.6 ± 1.1, and 46.5 ± 2.3 mg/g in 480 min, which are equal to almost 24% and 18% of the TA contents of the corresponding cryogels, respectively. The antioxidant properties of TA@CMC cryogels were examined, and worthy antioxidant properties were observed due to the TA. The alpha-glucosidase enzyme inhibition ability of the prepared cryogels was examined at different concentrations by grinding cryogels, and it was determined that TA@CMC 25% cryogel at 3 mg/mL concentration inhibited 70.4 + 1.3% of the enzyme. All bare CMC-based cryogels were found to be non-hemolytic with a less than 1% hemolysis ratio and also effective on the blood coagulation mechanism with blood-clotting index (BCI) values between 62.1 and 81.7% at 1 mg/mL concentrations. On the other hand, TA@CMC 25% cryogels exhibited a slight hemolytic profile with a 6.1 ± 0.8% hemolysis ratio and did not affect the blood coagulation mechanism with 97.8 ± 0.4% BCI value.

Closed-Loop Chemical Recycling of a Biobased Poly(oxanorbornene-fused γ-butyrolactone).

New polymers, properly designed for end-of-life and efficiently formed from renewable carbon, are key to the transition to a more sustainable circular plastics economy. Ring-opening polymerization (ROP) of bicyclic lactones is a promising method for the production of intrinsically recyclable polyesters, but most lactone monomers lack an efficient synthesis route from biobased starting materials, even though this is essential to sustainably account for material loss during the life cycle. Herein, we present the exceptionally rapid and controlled polymerization of a fully biobased tricyclic oxanorbornene-fused γ-butyrolactone monomer (M1). Polyester P(M1) was formed in low dispersity (D̵ = 1.2-1.3) and controllable molecular weight up to Mn = 76.8 kg mol-1 and exhibits a high glass transition temperature (Tg = 120 °C). The orthogonal olefin and lactone functionalities offer access to a wide range of promising materials, as showcased by postpolymerization modification by hydrogenation of the olefin, which increased polymer thermal stability by over 100 °C. Next to rapid hydrolytic degradation and solvolysis, the poly(oxanorbornene-fused γ-butyrolactone) could be cleanly chemically recycled back to the monomer (CRM), in line with its favorable ceiling temperature (Tc) of 73 °C. The density functional theory (DFT)-computed ΔH° of ring-opening with methanol of γ-butyrolactone-based monomers provided a model to predict Tc, and the DFT-computed and X-ray crystal structure-derived structural parameters of M1, hydrogenated analogue M1-H2, and regioisomer M2 offered insights into the structural descriptors that cause the high polymerizability of M1, which is key to establishing structure-property relations.