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At least 19 recordsLinked to original sources
PubMed2026

Acinetobacter guillouiae, a lipolytic strain isolated from sludge capable of partially depolymerising polyethylene terephthalate: genomic, proteomic, and biochemical insights.

Acinetobacter guillouiae I-MWF was isolated by incubating amorphous polyethylene terephthalate (PET) film in sludge samples. The strain partially depolymerised PET powder with 11.3% crystallinity, as confirmed by FT-IR, HPLC-UV, and LC-MS analyses. Extracellular enzymes released terephthalic acid (TPA), mono(2-hydroxyethyl) terephthalate (MHET), and bis(2-hydroxyethyl) terephthalate (BHET). Genomic analysis identified 18 putative extracellular hydrolases, including lipases and esterases, each with a conserved catalytic triad. Proteomic profiling revealed expression of two triacylglycerol lipases and two additional lipase-family proteins when the strain was cultivated with PET or a PET-Tween 80 mixture. These enzymes were cloned in Escherichia coli, but most formed insoluble, inactive inclusion bodies, and one was not expressed. Molecular modelling highlighted structural features likely to influence their catalytic interaction with PET. Although the strain partially depolymerised PET powder, it was unable to grow on PET, TPA, or ethylene glycol, indicating that PET depolymerisation occurs as a side activity rather than supporting growth. Instead, A. guillouiae displayed strong lipolytic activity and a clear preference for lipid-based substrates, achieving its highest growth with Tween 80. A lipid transporter was also expressed under these conditions, suggesting adaptation to hydrocarbon-rich environments. These findings indicate that A. guillouiae I-MWF can mediate partial PET depolymerisation without assimilating the resulting monomers, while preferentially growing on lipid-like substrates.

Acinetobacter↗
PubMed2026

Diet-dependent effects of an environmentally relevant dose of polyethylene and polyethylene terephthalate on white adipose tissue and systemic insulin resistance in mice.

As human exposure to micro- and nanoplastics (NPs) is unavoidable, it remains unclear whether dietary composition can modulate their health impacts. To address this, we investigated the metabolic effects of two common yet understudied polymers, polyethylene (PE) and polyethylene terephthalate (PET), in mice with either healthy or energy-dense diet. C57BL/6 J male mice were exposed to an environmentally relevant dose of PE or PET (100 nm, 25 mg/kg BW/day) for 29 weeks under either a normal diet (ND) or a high-fat diet (HFD). The metabolic consequence of NP exposure was highly diet-dependent. In ND-fed mice, PE and PET reduced white adipose tissue (WAT) mass, with PET inducing metabolic changes that toward a lipodystrophy-like state. Conversely, in HFD-fed mice, both polymers impaired systemic insulin sensitivity. Regardless of diet, PE and PET promoted immunoglobin G (IgG) accumulation in epididymal WAT, with PE-exposed lean mice exhibited the most robust IgG elevation, WAT fibrosis and impaired adipogenesis. These findings demonstrate that chronic, environmentally relevant PE or PET exposure disrupts metabolic health in male mice under both dietary contexts. While dietary composition dictates the specific metabolic phenotype, it does not prevent adverse outcomes. This complicates lifestyle-based mitigation strategies and underscores the urgent need for environmental source controls.

Insulin Sensitivity↗
PubMed1976

[The change of physical properties of plastics (polyoxymethylenecopolymer, polyethyleneterephthalate, polyethylene, polytetrafluorethylene) after animal implantation and autoclavation (author's transl)].

The change of physical properties of plastics (polyoxymethylene-copolymer, polyethyleneterephthalate, polyethylene, polytetrafluorethylene) and the bio-compatibility of these materials were examined by implantation in the backmuscle of 6-month-old male rabbits for 4 and 12 weeks and after autoclavation. We have found out, that after implantation and autoclavation polyethylene-terephthalate demonstrates a strong diminution of the visco-elastic qualities. Polyethylene and polytetrafluorethylene were not changed by these treatments. After an implantation of 12 weeks and an autoclavation of four times the visco-elastic properties of polyoxymethylene-copolymer were only slightly diminished by 10 to 15%. The histological investigation of the surrounding tissue demonstrated a very good bio-compatibility of polyethylene. After an implantation of 4 weeks polyoxymethylene-copolymer, polyethyleneterephthalate and polytetrafluorethylene produced a comparable foreign body reaction, which, however, was evidently diminished after an implantation of 12 weeks.

Animals↗
PubMed1975

[Polyamides and esters of terephthalic acid used in the production of medical articles to be sterilized by accelerated electrons].

The paper concerns the study on the resistance of home-made polyamides and polyterephthalic acid esters used for manufacture of medical equipment to the effect of accelerated electron radiation. The studied polyamides were found to be unfit for medical articles manufacture without removal of soluble components of the plastics. Sterilization with accelerated electrons results in limited advantageous changes in polyamide properties. Medical articles made of polyethylene terephthalate can be successfully sterilized in electron accelerator with no changes in characteristics even upon prolonged storage.

Electrons↗
PubMed1977

Reconstitution of craniofacial osseous contour deformities, sequelae of trauma and post resection for tumors, with an alloplastic-autogenous graft.

Our experience using a new technique for reconstructing contour defects of facial bones has been presented. It employs particulate, cancellous bone and an implantable prosthesis accurately fabricated of polyether urethane and polyethylene terephthalate cloth mesh which can be produced in a variety of configurations. A mannequin made of these materials displaying the various parts of the craniofacial complex that have been restored or are currently under investigation is shown in Figure 10. Large cranial vault defects, orbital floors, mandibles including chin augmentation, and nasal bone deformities have been successfully restored in man. Restoration of the pinna of the ear is currently being evaluated in laboratory animals.

Adolescent↗
PubMed1992

[New reconstruction method for defect of chest wall using composite graft].

In the case of a 64-year-old man squamous cell carcinoma in the left lung with metastasis to the rib, we excised the affected portion of the chest wall and used a composite graft, a combination hydroxyapatite (HAP) filler, for reconstruction with good results. HAP filler is a ceramic that combines the calcium phosphate apatite hydroxide with 3-calcium phosphate. The Dacron fabric used was made of polyethylene terephthalate fiber. Two layers of Dacron fabric were laid together, stitched to the rib with nylon thread, and the resulting tubular cavity packed with HAP filler to create an artificial rib. The intercostal muscle was sandwiched between the layers of Dacron fabric and the ends of the natural rib laid across those of the artificial one. We used the periosteum and intercostal muscle to integrate the graft and complete reconstruction. Postoperative recovery was good, and there was no visible sign of deformation at the graft site. Even in palpation we were unable to tell that the rib was artificial.

Biocompatible Materials↗
PubMed2025

Ultrahigh-throughput screening assay for PET-degrading enzymes.

In recent years, several PET-degrading enzymes have been identified from both known microorganisms and metagenomic sources in response to the growing environmental issue of polyethylene terephthalate (PET) accumulation. Despite this progress, there is a limited number of (ultra)high-throughput screening methods for assessing PET-hydrolyzing activity without relying on surrogate substrates. This method utilizes the coupled activity of ketoreductases (KREDs) and diaphorase to produce a fluorescent compound (resorufin) in the presence of PET degradation products, offering a more direct and efficient screening approach. A metagenomic KRED was coupled with the diaphorase from Clostridium kluyveri to enable the detection of the hydrolysis of PET degradation products catalyzed by the Bacillus subtilis BS2 esterase. The coupled reaction was established in water-in-oil microdroplets, encapsulating a single E. coli cell per droplet, demonstrating its potential for use in the ultrahigh-throughput screening of metagenomic libraries or randomized libraries for directed evolution campaigns.

High-Throughput Screening Assays↗
PubMed1979

Suture material as a factor in the occurrence of anastomotic false aneurysms. An analysis of 26 cases.

False aneurysm formation is a well-recognized late complication of prosthetic graft insertion. Despite the fact that other etiologic factors may be involved, the behavior of the suture material remains of central importance. In a retrospective review of 1,330 peripheral vascular cases, we found 26 cases involving a total of 39 false aneurysms, or an incidence of 2% (26/1,330). Twenty-four of these were directly attributable to failure of the monofilament plastic suture or silk suture material. Braided Dacron suture was used in the original anastomosis in another seven cases, and in these instances the false aneurysms were not related to suture failure but were association with such factors as previous endarterectomy, failure of arterial wall, and chronic hypertension. None of the 39 aneurysms was secondary to infection or trauma. These results emphasize the importance of using a braided, nonabsorbable suture material to ensure the continued integrity of an anastomosis involving prosthetic grafts.

Aged↗
PubMed1977

Reactions of the articular capsule to wear products of artificial joint prostheses.

Examination of a great number of tissue samples taken from the newly formed capsules surrounding artificial joints reveals small particles of prosthetic material. Abraded from the joint by wear and tear, these particles of plastic, metal, and acrylic cement initiate a foreign-body reaction and result in the formation of granulation tissue, including macrophages and foreign-body giant cells. Typical features of tissue reactions exist for each of the materials from which prostheses are made. The consequent formation of scar tissue produces a thickening of the capsule, which, in turn, may cause a reduction in the mobility of the joint. In small amounts, the foreign-body particles are eliminated via the perivascular lymph spaces. Where this transport system is insufficient to handle the volume, however, the foreign-body response may extend to the whole environment surrounding the joint. In such cases, there may be loosening of the cemented prosthetic parts because of deterioration of contiguous bone anchors by the tissue membrane lining the bone cement.

Foreign-Body Reaction↗
PubMed1975

Morphological studies in tissues surrounding alloarthroplastic joints.

Histological, histochemical and ultrastructural studies were done on soft tissue surrounding alloarthroplastic joints. In 38 cases a prosthesis of the hip joint and in 2 cases of the knee had to be exchanged and replaced. In most of the cases the reoperation became necessary because the anchoring of the prosthetic parts in the bone loosened. Up to 18 months after the first operation infection was responsible for the malfunctioning in some cases. Other complications were luxation and material faults. The morphological changes are determined by the tissue reaction to the different alloplastic materials used and by the time interval they remained in the organism. The large polymerized acrylic cement particles are phagozytosed by multinucleated foreign body giant cells. About 12 months following the implantation of the artificial joints small double refractile particles appear and evoke characteristic morphological changes. The particles are abraded by the continuous friction of the moving alloplastic or metallic surfaces of the prostheses. Usually they are phagozytosed by histiocytes, which form large granulomas and undergo degenerative changes as is indicated by the ultrastructural and histochemical findings. These alterations are more pronounced and occur sooner in prosthesis with parts (rotation ball or cup.) fabricated by polyester than in those made by polyethylene. The abraded particles not only are transported to the inguinal lymphnodes, but also to the tissue between prostheses and bone, where they induce the same morphological changes as in the capsule. Hence the fibrous membrane separating bone and prostheses increases in width, and the spongy bone is partially destroyed by the proliferating histiocytes. It is assumed that by impairing the anchoring this foreign body reaction to the abraded alloplastic particles is the leading cause of the loosening of this kind of artificial joints.

Acid Phosphatase↗
PubMed2026

Discovering hidden candidate plastic-degrading enzymes: Combined multi-omics and machine learning strategy.

Plastic pollution poses a major threat to the stability of natural ecosystems as well as human health. Microbial enzymes have long been considered a potential resource for targeted biodegradation but, except for a few successful cases, the discovery of efficient enzymes has proved challenging. Aiming to accelerate the process, we propose an approach combining metagenomics, metatranscriptomics and semi-supervised learning that selects promising plastic-degrading candidate enzymes from the proteome of relevant microorganisms. Tested on a dataset of over 10,000 microbial proteins, ranking models consistently prioritize known plastic-degrading enzymes, achieving an area under the cumulative distribution function curve above 0.96, with leave-one-family-out cross-validation indicating that performance is largely retained across protein families. As a case study, this work focuses on mixed microbial cultures exposed for extended periods to polyethylene, polyethylene terephthalate, and polyurethane substrates. The prevalent species after selective enrichment were functionally characterized, finding Rhodococcus aetherivorans as the most relevant species in two of the five cultures under investigation. Among the top-ranked proteins, several have high structural similarity with known enzymes despite not being identified by sequence similarity search. Moreover, according to metatranscriptomics results, several of these enzymes were found to be expressed at the same level or above that of annotated enzymes, suggesting that they may have functional relevance. Overall, this work highlights the potential of integrating multi-omics with data-driven methods for enzyme discovery and for accelerating the development of biotechnological solutions to plastic pollution.

Biodegradation, Environmental↗
PubMed2026

Controlled framework nickel exsolution in metal-organic frameworks creates confined active sites for chemoselective citral hydrogenation.

Selective hydrogenation of citral to citronellal over non-noble-metal catalysts remains challenging because highly active metallic Ni simultaneously promotes efficient substrate activation and undesired over‑hydrogenation of the desired product. Herein, we develop a controlled exsolution strategy in waste polyethylene terephthalate (PET)-derived nickel metal-organic frameworks (Ni-MOFs) to transform framework Ni into confined metallic active sites while preserving the porous framework architecture. During reductive treatment, framework Ni2+ species undergo gradual node-to-metal evolution, generating highly dispersed Ni0 sites confined within the partially retained MOF framework. More importantly, the degree of framework Ni exsolution governs the balance between citral activation and citronellal over‑hydrogenation, thereby establishing a distinct chemoselective window. Within the optimal exsolution regime, the framework-confined Ni0 sites enable efficient H2 activation and selective hydrogenation of the CC bond while suppressing the subsequent hydrogenation of citronellal. Consequently, the optimized catalyst achieves ∼99% citral conversion and 100% citronellal selectivity at 90 °C and 2 MPa H2, together with excellent catalytic stability and recyclability. Beyond the sustainable valorization of waste PET, this work establishes controlled framework exsolution as an effective strategy for engineering confined active sites and regulating chemoselectivity in non-noble-metal hydrogenation catalysts.

Chemoselective hydrogenation↗
PubMed2026

Amino acid reprogramming and biofilm-specific tricarboxylate transporters in PET-degrading Piscinibacter sakaiensis.

Plastic-degrading bacteria predominantly colonize polymer surfaces as biofilms, yet it remains unclear whether the biofilm phenotype contributes to metabolism beyond retaining extracellular enzymes. Here, we combine population-level RNA-sequencing across three conditions-biofilm cells on polyethylene terephthalate (PET), planktonic cells incubated with PET, and planktonic cells on maltose-with single-cell Raman spectroscopy to characterize the PET response of Piscinibacter sakaiensis (formerly Ideonella sakaiensis). This integrated approach reveals two metabolically distinct response layers. A carbon-source-driven response shared by all PET-exposed cells is dominated by a broad amino acid reprogramming, led by upregulation of branched-chain amino acid transport genes, enhanced serine biosynthesis, and reduced chemotaxis. A biofilm-specific layer selectively induces tripartite tricarboxylate transporter genes from three distinct genomic loci. This transcriptional feature is accompanied by a single-cell phenotype consistent with a protein-rich and saturated membrane. These results suggest that biofilm formation is not limited to enzyme retention but is associated with selective activation of transport systems, consistent with a putative role in capturing PET-derived intermediates at the polymer interface. This two-layer model separates general metabolic adaptation to PET from biofilm-specific functions and provides a framework for understanding how surface-associated bacterial physiology contributes to plastic degradation.IMPORTANCEPolyethylene terephthalate (PET) degradation in natural and engineered environments is largely mediated by surface-attached microbial communities, yet the physiological role of biofilm state during plastic degradation remains poorly understood. Using the model PET degrader Piscinibacter sakaiensis, we show that biofilm-associated cells are not simply retained near the polymer surface but exhibit a distinct metabolic program characterized by selective induction of tripartite tricarboxylate transporters. In contrast, extensive amino acid reprogramming occurs in both biofilm and planktonic PET-exposed cells, indicating that it is driven by carbon source rather than surface attachment. These findings reveal that PET degradation involves two separable physiological layers: a general metabolic response to PET-derived carbon shared across cell phenotypes, and a biofilm-specific transport response potentially linked to substrate capture at the plastic interface. This work advances our understanding of how microbial physiology is organized during plastic biodegradation and identifies transport processes as previously unrecognized components of PET-degrading biofilms.

PET biodegradation↗
PubMed2026

Ageing effects on chemical, physical, mechanical, and morphological properties of clear aligners - a systematic review.

BACKGROUND: Clear aligner (CA) therapy has experienced rapid use over the past two decades to treat orthodontic malocclusions. However, evidence on CA material degradation in the oral environment remains limited and often focuses on single brands or isolated material properties. OBJECTIVES: To investigate CA ageing characteristics across different materials and brands and evaluate the chemical, physical, mechanical, and morphological changes following simulated or intraoral ageing. SEARCH METHODS: Five databases (PubMed, Web of Science, MEDLINE [Ovid], ProQuest, and Scopus) were searched to 18 March 2026, with no restrictions. ELIGIBILITY CRITERIA: Studies assessing CA properties after intraoral use or simulated ageing (thermocycling, cyclic loading, or liquid immersion) were included. DATA COLLECTION AND ANALYSIS: Study selection followed PRISMA 2020. RoB was assessed using QUIN for purely in vitro studies, JBI for cohort in vivo studies, and Cochrane RoB 2 for RCTs. Results were synthesised narratively and organised by property domain, as substantial methodological heterogeneity precluded formal meta-analysis. Where protocols were comparable, a simple pooled weighted mean was calculated and presented graphically. RESULTS: Ninety-five studies were included. RoB was low in eight studies, moderate in sixty-two, and high in twenty-five. Chemical composition remained largely stable during ageing, though some brands showed trace elemental release. Physical, mechanical, and morphological properties showed material-dependent deterioration. Pooled discolouration was greatest with coffee (weighted mean ΔE = 70.9), versus tea (ΔE = 18.4) and red wine (ΔE = 11.5), with Invisalign® consistently exceeding the clinically perceptible threshold. Force decay of 40-90% typically occurred within 48 h. Thermoplastic polyurethane (TPU)-based and directly printed aligners (DPAs) generally showed greater susceptibility than polyethylene terephthalate glycol-modified (PETG)-based aligners, though findings on hardness, roughness, and stiffness were inconsistent. CONCLUSIONS: CA materials undergo clinically relevant degradation during use, particularly in TPU-based and DPAs aligners. Clinicians may need to prioritise material-specific protocols, reinforce dietary and cleaning instructions, and consider force decay when determining aligner replacement intervals. PROSPERO number: CRD420251110248.

Humans↗
PubMed1976

[Bio-compatibility of different plastics (polyoxymethylene-copolymer, polyethylensterephthalate, polyethylene, polytetrafluorethylene) (author's transl)].

The bio-compatibility of different plastic materials were examined after their implantation in the back-muscle of 6-months-old male rabbits. Twelve weeks after the implantation chemical measurements (DNS-concentration of the tissue) and histological investigations of the surrounding tissue demonstrated for polyethylene the best bio-compatibility.

Animals↗