Polymer Degradation Research Articles

A Numerical Study on the Drug Release Process of Biodegradable Polymer Drug-Loaded Vascular Stents

Biodegradable polymer drug-loaded vascular stents are a typical and promising application in the field of invasive interventional therapy. The drug release process of drug-loaded vascular stents, as well as the drug concentration in the vascular wall and its change process, will affect the therapeutic effect of vascular stents on vascular stenosis. As a drug carrier, the degradation properties of the polymer will affect the drug release process. In this study, the drug release process from the biodegradable polymer stent and the drug delivery process in vascular lumens and intravascular walls were studied by using 3D finite element method, with the effect of the biodegradation behavior of polymer on the drug release process being considered. The effects of the initial drug concentration, stent geometry, and polymer degradation rate on the drug release and delivery process were investigated. The results showed that the initial drug concentration and the thickness of the polymer stent significantly affected the drug concentration in the middle layer of the vessel wall, but the initial drug concentration had no effect on the drug release duration. The degradation of the polymer causes its porosity to change with time, which affects the drug diffusion in polymer, and further affects the drug concentration in the vessel wall. The three-dimensional structure of the stent can affect the blood flow in the blood vessel, resulting in drug deposition near the struts, especially near the intersection of the support struts and the bridge struts.

Versatile and Controlled Synthesis of Degradable, Water-Soluble Bottlebrush Polymers with Poly(disulfide) Backbones Derived from α-Lipoic Acid.

Bottlebrush (BB) polymers, with their densely grafted side chains and unique architecture, are highly advantageous for drug delivery due to their high functional group density for drug conjugation, unimolecular nature, and enhanced biodistribution properties. These attributes enable extended blood circulation half-life, improved tumor tissue penetration, and high tumoral drug accumulation. However, the typically nondegradable, all-carbon backbones of most BB polymers limit their suitability for applications requiring controlled clearance and biodegradability. To address this, we developed degradable BB polymers with poly(disulfide) backbones synthesized via reversible addition-fragmentation chain transfer (RAFT) copolymerization of α-lipoic acid (LA), a renewable and readily available compound, with acrylate-based inimers. These copolymers feature degradable backbones and initiating sites for subsequent BB synthesis. Using an atom transfer radical polymerization (ATRP) grafting-from methodology, we synthesized BB polymers with relatively low dispersities (Đ = 1.30-1.53), high backbone degrees of polymerization (DPbb), and high molar masses (Mn,MALS = 650-2700 kg/mol). The easily cleavable disulfide bonds enabled backbone degradation under mild reducing conditions. Beyond hydrophilic BB with tri(ethylene glycol) methyl ether acrylate (TEGA) side chains, we synthesized BB with cationic, anionic, and zwitterionic side chains, demonstrating broad monomer compatibility. This scalable approach produces water-soluble, degradable BB polymers with tunable architectures and predictable molecular weights. By addressing the need for degradability in BB polymers, this work advances their potential for drug delivery, offering enhanced functionality, biocompatibility, and sustainability.

Degradation of polyester coil-coated materials by accelerated weathering investigated by FTIR-ATR chemical imaging and impedance analysis

In the present study, ex situ Fourier transform infrared (FTIR) chemical imaging and in situ electrochemical impedance spectroscopy (EIS) were combined to investigate the ageing process of a polyester/melamine coil-coated steel. The samples were first subjected to a QUV accelerated weathering test for 250 h up to 2000 h, followed by immersion in a 0.5 M NaCl solution to assess water uptake and polymer matrix plasticization. FTIR analyses revealed chemical degradation, including chain scission and the formation of polar groups, between 500 h and 2000 h of QUV exposure. Degradation effects were observed throughout the whole topcoat, with more significant degradation occurring near the surface. EIS measurements indicated greater water uptake with increasing QUV exposure, highlighting two regions of water sorption: an initial rapid Fickian diffusion region and a slower non-Fickian region. The time constant (τ) analysis, which was extracted from the EIS data and related to the dielectric manifestation of the glass transition, confirmed polymer matrix plasticization due to water uptake. Despite UV-induced degradation, the polymer maintained effective protective properties, as evidenced by the high low-frequency impedance unaffected by UV exposure or immersion duration (1 week). This methodology successfully identified ageing markers, providing a framework for studying UV degradation mechanisms, water uptake, and polymer mobility in anticorrosion coatings.

Influence of Food Pigments and Thermal Aging on the Color Stability of Denture Base Resins

Color stability of acrylic resins is essential for preserving the aesthetic appearance of denture bases over time. This study explores how food pigments and thermal changes affect the color stability of commonly used denture base resins. Four acrylic resins were tested: three heat-cured acrylic resins with different characteristics (Zhermack® Villacryl H Plus V2, H Plus V4, and H Rapid FN V4) and one self-cured acrylic resin (Zhermack® Villacryl S V4). To simulate the oral environment, the resins underwent 1000 thermal cycles between 5 °C and 55 °C, followed by a 7-day immersion period in beverages such as coffee, red wine, a caramel-colored soft drink (cola), and distilled water (control), forming sixteen group of specimens (n = 5). Color changes (∆E) were measured using the VITA Easyshade V® spectrophotometer, following the CIEDE2000 standard. The findings revealed that thermal aging caused noticeable color changes in all resins (p < 0.001). Red wine led to the most intense discoloration, followed by coffee. The caramel-colored soft drink caused moderate staining, while distilled water had a negligible effect. The type of polymerization did not affect the degree of discoloration, as no significant differences were found between the resins after exposure to beverages (p > 0.05). Overall, this study highlights how both internal and external factors impact the appearance of acrylic resins. Thermal aging can accelerate polymer degradation, while pigments in beverages cause visible staining. Among the tested beverages, red wine proved to be the most aggressive due to its high pigment concentration and low pH. These findings emphasize the need for improved material formulations to enhance the longevity and aesthetic performance of dentures.

Poly(curcumin-co-poly(ethylene glycol)) films provide neuroprotection following reactive oxygen species insult in vitro

Objective.Curcumin is an antioxidant and anti-inflammatory molecule that may provide neuroprotection following central nervous system injury. However, curcumin is hydrophobic, limiting its ability to be loaded and then released from biomaterials for neural applications. We previously developed polymers containing curcumin, and these polymers may be applied to neuronal devices or to neural injury to promote neuroprotection. Thus, our objective was to evaluate two curcumin polymers as potential neuroprotective materials for neural applications.Approach.For each curcumin polymer, we created three polymer solutions by varying the weight percentage of curcumin polymer in solvent. These solutions were subsequently coated onto glass coverslips, and the thickness of the polymer was assessed using profilometry. Polymer degradation and dissolution was assessed using brightfield microscopy, scanning electron microscopy, and gel permeation chromatography. The ability of the polymers to protect cortical neurons from free radical insult was assessed using anin vitrocortical culture model.Main results.The P50 curcumin polymer (containing greater poly(ethylene glycol) content than the P75 polymer), eroded readily in solution, with erosion dependent on the weight percentage of polymer in solvent. Unlike the P50 polymer, the P75 polymer did not undergo erosion. Since the P50 polymer underwent erosion, we expected that the P50 polymer would more readily protect cortical neurons from free radical insult. Unexpectedly, even though P75 films did not erode, P75 polymers protected neurons from free radical insult, suggesting that erosion is not necessary for these polymers to enable neuroprotection.Significance.This study is significant as it provides a framework to evaluate polymers for future neural applications. Additionally, we observed that some curcumin polymers do not require dissolution to enable neuroprotection. Future work will assess the ability of these materials to enable neuroprotection withinin vivomodels of neural injury.

From biofilms to biocatalysts: Innovations in plastic biodegradation for environmental sustainability.

The increase in plastic waste has evolved into a severe environmental crisis, which requires innovative recycling technologies to repurpose used plastic with adequate environmental protection. This review highlights the urgent need for innovative approaches to the treatment and degradation of post-use plastics. It investigates the promising role of biofilms in the biodegradation of polymers, especially for polymers such as polyethylene terephthalate (PET), polyurethane (PU), and polyethylene (PE). By examining biofilms, researchers can determine key enzymes involved in polymer degradation and improve their efficiency through genetic engineering. In addition, the review explores in detail the structure and development of biofilms on polymeric surfaces, elucidating the role of specific microbial strains necessary for biofilm formation and maintenance. Techniques for identifying enzymes within biofilms and improving their degradation ability are also discussed. The review concludes with recent discoveries in enzyme isolation and the key role of biofilms in the degradation and recycling of major plastic pollutants such as PET, PU, and PE. These findings highlight the potential of biofilm-derived enzymes to promote sustainable polymer recycling.

Investigating the Degradability and Optoelectronic Properties of π-Conjugated Polymers with 1,2,4-Chalcogenadiazole Linkers

Investigating the Degradability and Optoelectronic Properties of π-Conjugated Polymers with 1,2,4-Chalcogenadiazole Linkers

Prilling as an Effective Tool for Manufacturing Submicrometric and Nanometric PLGA Particles for Controlled Drug Delivery to Wounds: Stability and Curcumin Release.

This study investigates for the first time the use of the prilling technique in combination with solvent evaporation to produce nano- and submicrometric PLGA particles to deliver properly an active pharmaceutical ingredient. Curcumin (CCM), a hydrophobic compound classified under BCS (Biopharmaceutics Classification System) class IV, was selected as the model drug. Key process parameters, including polymer concentration, solvent type, nozzle size, and surfactant levels, were optimized to obtain stable particles with a narrow size distribution determined by DLS analysis. Particles mean diameter (d50) 316 and 452 nm, depending on drug-loaded cargo as Curcumin-loaded PLGA nanoparticles demonstrated high encapsulation efficiency, assessed via HPLC analysis, stability, and controlled release profiles. In vitro studies revealed a faster release for lower drug loadings (90% release in 6 h) compared to sustained release over 7 days for higher-loaded nanoparticles, attributed to polymer degradation and drug-polymer interactions on the surface of the particles, as confirmed by FTIR analyses. These findings underline the potential of this scalable technique for biomedical applications, offering a versatile platform for designing drug delivery systems with tailored release characteristics.

Characterization of Ultraviolet-Degraded Polyethylene Terephthalate Film Using a Complementary Approach: Reactive Pyrolysis–Gas Chromatography–Mass Spectrometry and Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry

Polyethylene terephthalate (PET) is widely used across various industries owing to its versatility and favorable properties, including application in beverage bottles, food containers, textile fibers, engineering resins, films, and sheets. However, polymer materials are susceptible to degradation from factors such as light, oxygen, and heat. Therefore, it is crucial to understand the structural changes that occur during degradation and the extent of these changes. This report investigates the structural alterations in PET films resulting from ultraviolet (UV) irradiation utilizing pyrolysis-gas chromatography time-of-flight mass spectrometry (Py-GC-TOFMS) and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOFMS). Using the reactive Py-GC-TOFMS, we estimated the composition of the pyrolysis products resulting from UV degradation through electron ionization, soft ionization, and exact mass measurements. Additionally, artificial intelligence (AI)-based structure analysis was performed to evaluate these compounds' structures. Notably, most degradation products were not found in the National Institute of Standards and Technology database, underscoring the effectiveness of our approach. Using MALDI-TOFMS analysis, we determine the changes in the end groups before and after UV irradiation. This analysis confirmed the generation of a series of carboxylic acid end groups as a result of degradation, a polymer series not detected by reactive pyrolysis GC-MS. We also explored degradation in the depth direction, demonstrating that degradation progresses gradually to depths of several micrometers. Our findings highlight the importance of employing mass spectrometry techniques for a comprehensive analysis of polymer degradation.

SELECTION OF POLYMER FOR STENT-GRAFT COATING IN TERMS OF BIOCOMPATIBILITY AND BIODEGRADATION CHARACTERISTICS

HighlightsCoated stents or stent-grafts are widely used in endovascular surgery to close arterial perforations, dissections and aneurysms, as well as in stenting of arteries with loose atherosclerotic plaques in order to reduce the risk of emboli and strokes. The material of stent coating is of great importance in the prevention of early thrombosis and restenosis of stent grafts. Biodegradable polymers have an advantage over non-biodegradable polymers because they do not remain in the patient's tissues for a long period of time and do not cause chronic inflammation. The study of the dynamics and biodegradation characteristics of polymer coating can provide information about its suitability and safety in the stent graft. Annotation Aim. To screen potentially suitable polymers for stent-graft coating with the following assessment of biocompatibility and biodegradation dynamics in an in vivo experiment.Methods. The coating was applied on the stent by electrospinning from a solution of polymers: Polycaprolactone (PCL); polydioxanone (PDO); polylactide-co-caprolactone (P(LA/CL)) with lactide: caprolactone ratio – 70:30; polylactide-co-glycolide (PLGA) with lactide: glycolide ratio – 50:50. Chloroform (CHCl3) and 1,1,1,1,3,3,3,3,3-hexafluoro-2-propanol (HFP) were used as a solvent. Gore-Tex polymer membrane made of polytetrafluoroethylene (ePTFE) was used as control. In order to evaluate biocompatibility and biodegradation dynamics in vivo, the studied polymeric samples were implanted subcutaneously in male Wistar rats for periods of 7 and 14 days, 1, 2, 3 and 6 months. After explantation all samples were studied histologically.Results. 14 days after implantation a moderate inflammatory reaction developed on all polymer specimens. The PTFE material was separated from the surrounding tissues by a thin ordered fibrous capsule, confirming its satisfactory biocompatible properties. The porous structure of PCL membranes was filled by fibroblasts and the specimens were tightly integrated into the surrounding tissues. P(LA/CL) degrades with the formation of large fragments. The composite polymer P(LA/CL)/PDO degraded to form small fragments that are tightly integrated with the fibrous capsule. PLGA membranes showed high rates of degradation - membrane fragments were detected 3 months after implantation, after 6 months the samples were completely degraded.Conclusion. The results of biocompatibility and biodegradation assessment in vivo indicate that the most promising polymers for stent-graft creation are PCL, PLGA and composite polymer P(LA/CL)/PDO. In order to finalize the choice of polymer, it is necessary to conduct further studies to assess the biocompatibility and degradation of polymer coating during implantation of stent-grafts into the arterial bed of large laboratory animals.

De Novo Assembly of the Polyhydroxybutyrate (PHB) Producer Azohydromonas lata Strain H1 Genome and Genomic Analysis of PHB Production Machinery.

Polyhydroxybutyrate (PHB) is a biodegradable natural polymer produced by different prokaryotes as a valuable carbon and energy storage compound. Its biosynthesis pathway requires the sole expression of the phaCAB operon, although auxiliary genes play a role in controlling polymer accumulation, degradation, granule formation and stabilization. Due to its biodegradability, PHB is currently regarded as a promising alternative to synthetic plastics for industrial/biotechnological applications. Azohydromonas lata strain H1 has been reported to accumulate PHB by using simple, inexpensive carbon sources. Here, we present the first de novo genome assembly of the A. lata strain H1. The genome assembly is over 7.7 Mb in size, including a circular megaplasmid of approximately 456 Kbp. In addition to the phaCAB operon, single genes ascribable to PhaC and PhaA functions and auxiliary genes were also detected. A comparative genomic analysis of the available genomes of the genus Azohydromonas revealed the presence of phaCAB and auxiliary genes in all Azohydromonas species investigated, suggesting that the PHB production is a common feature of the genus. Based on sequence identity, we also suggest A. australica as the closest species to which the phaCAB operon of the strain H1, reported in 1998, is similar.

Aging of drinking water transmission pipes during long-term operation as a potential source of nano- and microplastics

Microplastics (MPs) and nanoplastics (NPs) released into drinking water from transmission pipes can pose a potential health risk to consumers. This paper presents the results of a comprehensive study of PE and PVC pipes after long-term operation in drinking water distribution networks, which confirmed that degradable polymers can be a significant source of MPs. Both plastics age relatively quickly, and the degree of damage to the pipe surface depends on the time and operating conditions. During aging, polymer chains deteriorate, leading to a weakening of the structure and increased amorphousness of the plastics. As a result, the surfaces of PE and PVC crack and peel, resulting in the formation of particles with sizes corresponding to NP and MP with high potential for release into water. The magnitude of the phenomenon increases as the diameter of the pipes decreases, indicating that the most vulnerable customers are those at the ends of the network to which drinking water is supplied through small-diameter pipes. Aging PE and PVC pipes should be considered a real and very important source of MPs and NPs in drinking water, and water quality in this aspect should be monitored by manufacturers.

A general strategy towards activatable nanophotosensitizer for phototoxicity-free photodynamic therapy.

Background: Photodynamic therapy (PDT) has gained widespread attention in cancer treatment, but it still faces clinical problems such as skin phototoxicity. Activatable photosensitizers offer a promising approach to addressing this issue. However, several significant hurdles need to be overcome, including developing effective activation strategies and achieving the optimal balance between photodynamic effects and related side effects. Herein, we present a novel and general strategy for the construction of tumor-targeted activatable nanophotosensitizers (TNP1/PSs). Methods: TNP1/PSs were constructed through simple nanoprecipitation method, leveraging the strong cation-π interaction between cationic polymers and aromatic photosensitizers. We conducted a comprehensive characterization and investigation of the photoactivity, as well as the mechanisms underlying both OFF state and switched-on properties of TNP1/PSs. Additionally, we thoroughly evaluated the cytotoxicity, tumor-targeted ability, and anti-tumor efficacy of TNP1/PSs in the 4T1 cell line. Results: TNP1/PSs exhibit a markedly fully OFF state of photoactivity, subsequent to self-assembly through cation-π interactions in aqueous media. The mechanism study reveals a multi-pathway process induced by cation-π complexes, which includes reduced absorption and radiative decay, as well as enhanced thermal decay and intermolecular charge transfer. Upon targeting tumor cells, TNP1/PSs were effectively endocytosed and predominantly traversed the lysosomes, where degradation of the cationic polymer occurs, resulting in the spontaneous switch-on of PDT activity. In vivo studies employing small animal models demonstrated that the as-synthesized nanophotosensitizer possesses remarkable anti-tumor activity while completely avoiding skin phototoxicity. Conclusion: This work provides a powerful platform for efficiently constructing tumor-targeted activatable nanophotosensitizers, paving the way for safe and effective photodynamic therapy in cancer treatment.

Impact of solvolysis on the decomposition efficiency of poly(lactic acid) materials with insight into their non-uniform architecture.

A more recent insight into the structural differences of sustainable poly(lactic acid)-based materials was revealed through a solvolysis reaction under environmentally friendly conditions. The decomposition process clarified the heterogeneous structure of the investigation polymers. It was found that materials used for nanofiber production degraded 25 % more poorly compared to materials suitable for packaging materials. The resultant product, ethyl lactate, demonstrated high purity and yield (up to 900 mg·L-1, 98 %). The degree and effect of decomposition of the poly(lactic acid) were monitored by employing the gel permeation chromatic method, differential scanning calorimetry and thermal gravimetric analysis. X-ray diffraction was conducted to assess differences between the crystalline portions of polymers. The yield and purity of the product were verified by gas and liquid chromatography. The kinetic studies evaluated the rate of polymers degradation connected with chemical structure and temperature. A structural difference was observed in the studied polylactides, with approximately a 15 % deviation in crystallinity. This observed variation resulted from differences in arrangement and chain lengths, as well as the terminal functional groups, leading to non-uniform degradation of both polymers. This study offers a new insight on the degradation efficiency of polymers highlights the non-uniformity of their structure. Converting biodegradable polymer waste into a suitable and reusable product as part of an environmentally friendly approach will contribute to the sustainability of polymer materials.

Anion-induced chiral assembly: construction of Ag(i) coordination polymers for photocatalytic degradation of organic dyes

Assembly of a racemic ligand with different Ag(i) salts leads to homo/heterochiral polymers. The photocatalytic experiments indicate CPs 4–8 are active for the degradation of rhodamine B and methylene blue under UV irradiation.

Development of an Acid-Soluble Residue-Free Drill-In Fluid: Eliminating Reservoir Damage with Waxy Corn Starch

Summary Completely removing and dissolving the mudcake formed by drill-in fluid (DIF) without any residue is a challenging and complex task during the well completion process, as mudcake removal involves polymer degradation and dissolution of filtration reducer. As a traditional technique, a combination of gel breakers and acids is applied to remove mudcake; this method can degrade polymers and dissolve acid-soluble materials, such as calcium carbonate, but it cannot dissolve filtration reducers, such as starch. This drawback allows filtration reducers to easily enter reservoir pores, eventually causing particle blockage damage that is difficult to be removed by inorganic or organic acids. In this study, based on the acid hydrolysis rates (AHRs) of waxy corn starch (WCS) and normal corn starch (NCS), the differences in turbidity of the resulting solutions, and the characteristic of the acid-hydrolyzed WCS without residue, an acid-soluble residue-free DIF (RF-DIF) was developed using WCS as a filtration reducer. Acid residue tests of the mudcakes formed by the DIF on the discs were conducted, and the microscopic pores within the discs were analyzed. Moreover, the reservoir protection performance of the DIF was evaluated, and the pore distribution and connectivity of the treated cores were reconstructed. The experimental results showed that the outer and inner mudcakes formed by DIF containing WCS (Waxy-DIF), which appeared on the surface and inside of the ceramic filter discs, respectively, could be completely dissolved by acid, resulting in the acid solution with a turbidity of less than 30 nephelometric turbidity units (NTU). By comparison, the mudcakes formed by the DIF with NCS (Normal-DIF) could not be completely dissolved by acid, leading to high turbidity. In addition, under the same conditions, the permeability recovery rates of the cores treated with Waxy-DIF and Normal-DIF were 100% and 83.17%, respectively, indicating that Waxy-DIF was more effective in protecting the reservoir, which can meet the needs of oil and gas production.

PH-responsive supramolecular switch of a rationally designed dipyrroethene-based chromophore.

Herein, we present a strategy to access a novel class of pH-responsive, dual-state emissive (DSE), highly fluorescent pyrrole-based chromophores via diformylation of dipyrroethenes (DPE) followed by condensation with various aniline derivatives. The DPE-based chromophores exhibit a large Stokes shift and maintain good fluorescence quantum yields. Remarkably, these chromophores demonstrate reversible colourimetric changes and a fluorometric 'on-off-on' switch in response to pH variations. Various spectroscopic techniques, optical microscopy, X-ray crystallography, and computational studies revealed that the synthesized molecules adopt a two-dimensional conformation due to the presence of strong π⋯π stacking and hydrogen bonding interactions, allowing them to function as flexible molecular hosts. Under acidic conditions, selective protonation of imine bonds and subsequent complexation with the counter anion enhance the host-guest interactions, resulting in a stable three-dimensional supramolecular structure. Notably, the reversibility of these molecules under basic conditions showcases the robustness and potential applications of these chromophores in various fields, ranging from the design of finely tuned pH-responsive degradable polymers to self-healing materials, as well as sensing and molecular devices.

Topical siRNA therapy of diabetic-like wound healing.

Non-healing wounds are a serious complication in diabetic patients. One of the detrimental factors contributing to limited wound healing is the accumulation of metalloproteinase-9 (MMP-9) in the wound. Selective inhibition of MMP-9 is one of the established therapeutic targets for diabetic wound healing. Here, a functional and biocompatible wound dressing is developed to enable a controlled release of a traceable vector loaded with the antisense siRNA against MMP-9 in the wound. The dressing consists of degradable polymer nanofibers embedded with a vector nanosystem - polymer-coated fluorescent nanodiamonds optimized for the binding of siRNA and colloidal stability of nanodiamond-siRNA complexes in a physiological environment. The developed dressing is tested on murine fibroblasts and also applied to wounds in a diabetic murine model to evaluate its suitability in terms of in vivo toxicity, biological efficacy, and handling. The treatment results in significant local inhibition of MMP-9 and a shortening of the wound healing time. The scar formation in treated diabetic-like mice becomes comparable with that in non-treated diabetes-free mice. Our results suggest that the application of our biocompatible dressing loaded with a non-toxic vector nanosystem is an effective and promising approach to gene therapy of non-healing wounds.

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.

Biomechanics identification and risk management strategy of volatile organic compound pollution sources integrated with machine learning algorithms

Microplastic pollution has emerged as a critical environmental issue, posing significant threats to aquatic ecosystems and human health. As an innovative approach, biological techniques have shown great potential in mitigating microplastic contamination in water systems. This study explores the use of biotechnological methods, such as microbial degradation and biofilm-assisted filtration, in combination with conventional water treatment processes to enhance the removal of microplastics. Focusing on Southwest China, where water pollution is exacerbated by rapid urbanization and industrial activities, the research identifies the ecological and technical challenges unique to this region. Experimental approaches include optimizing bio-coagulation using microbial consortia, assessing enzymatic degradation of common microplastic polymers, and evaluating the biomechanical interactions between biological agents and microplastic particles during water filtration. Results aim to provide insights into the efficacy and scalability of integrating biological solutions into existing water treatment frameworks. This study contributes to developing sustainable and eco-friendly strategies for addressing microplastic pollution and safeguarding water quality through biologically informed interventions.