-
Microbiological Research Dec 2023The urgent need for better disposal and recycling of plastics has motivated a search for microbes with the ability to degrade synthetic polymers. While microbes capable...
The urgent need for better disposal and recycling of plastics has motivated a search for microbes with the ability to degrade synthetic polymers. While microbes capable of metabolizing polyurethane and polyethylene terephthalate have been discovered and even leveraged in enzymatic recycling approaches, microbial degradation of additive-free polypropylene (PP) remains elusive. Here we report the isolation and characterization of two fungal strains with the potential to degrade pure PP. Twenty-seven fungal strains, many isolated from hydrocarbon contaminated sites, were screened for degradation of commercially used textile plastic. Of the candidate strains, two identified as Coniochaeta hoffmannii and Pleurostoma richardsiae were found to colonize the plastic fibers using scanning electron microscopy (SEM). Further experiments probing degradation of pure PP films were performed using C. hoffmannii and P. richardsiae and analyzed using SEM, Raman spectroscopy and Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR). The results showed that the selected fungi were active against pure PP, with distinct differences in the bonds targeted and the degree to which each was altered. Whole genome and transcriptome sequencing was conducted for both strains and the abundance of carbohydrate active enzymes, GC content, and codon usage bias were analyzed in predicted proteomes for each. Enzymatic assays were conducted to assess each strain's ability to degrade naturally occurring compounds as well as synthetic polymers. These investigations revealed potential adaptations to hydrocarbon-rich environments and provide a foundation for further investigation of PP degrading activity in C. hoffmannii and P. richardsiae.
Topics: Plastics; Polypropylenes; Ascomycota; Fungi; Biodegradation, Environmental
PubMed: 37793281
DOI: 10.1016/j.micres.2023.127507 -
Environment International Sep 2023Microplastics residues in natural waters can adsorb organic contaminants owing to their rough surface morphology and high specific surface area, potentially harming...
Microplastics residues in natural waters can adsorb organic contaminants owing to their rough surface morphology and high specific surface area, potentially harming human health when ingested. Although humans inevitably ingest microplastics, the bioaccessibility of microplastic-associated chemicals in the human gastric and intestinal fluids remains unresolved. This study investigated the mechanism and primary factor controlling the bioaccessibility of polypropylene (PP) microplastic fiber-associated tetracycline (TC) and ciprofloxacin (CIP) in simulated human gastrointestinal fluids. After mixing 0.1 g of PP microfiber with 10 mg/L of TC (or CIP) for 96 h and exposure to simulated human gastrointestinal fluids, the TC concentrations were 0.440, 0.678, and 1.840 mg/L and the CIP concentrations were 0.700, 1.367, and 3.281 mg/L CIP in the simulated human saliva, gastric, and intestinal fluids after incubation for 60 s, 4 h, and 8 h, respectively. This indicated that the antibiotics TC and CIP adsorbed onto microfiber surface are readily released into human gastrointestinal fluids upon ingestion. Gastric and intestinal fluids showed enhanced bioaccessibility to TC/CIP adhered to PP microfiber. The primary factors affecting the bioaccessibility to TC/CIP adhered to PP microfiber surfaces were found to be pepsin in human gastric fluid and trypsin in human intestinal fluid. Molecular docking and simulated molecular dynamic analyses results showed that pepsin and trypsin stablish connections with TC via hydrogen bonds (reaction sites: pepsin TC: T, T, S, D, D and Y; trypsin TC: S, H, K, G, and G) and CIP via hydrophobic interactions (reaction sites: pepsin CIP: Y, T, T, F, I, V, and I; trypsin CIP: W, I, C, and C). Our findings highlight that microplastic ingestion increases the risk of microplastics and the co-contaminants adsorbed to human health; thus, these findings are helpful to assess the risk of microplastics and co-contaminants to human health.
Topics: Humans; Ciprofloxacin; Microplastics; Plastics; Polypropylenes; Molecular Docking Simulation; Pepsin A; Trypsin; Anti-Bacterial Agents; Tetracycline
PubMed: 37703772
DOI: 10.1016/j.envint.2023.108193 -
Journal of the American Society For... Aug 2023Sample preparation for single-cell proteomics is generally performed in a one-pot workflow with multiple dispensing and incubation steps. These hours-long processes can...
Sample preparation for single-cell proteomics is generally performed in a one-pot workflow with multiple dispensing and incubation steps. These hours-long processes can be labor intensive and lead to long sample-to-answer times. Here we report a sample preparation method that achieves cell lysis, protein denaturation, and digestion in 1 h using commercially available high-temperature-stabilized proteases with a single reagent dispensing step. Four different one-step reagent compositions were evaluated, and the mixture providing the highest proteome coverage was compared to the previously employed multistep workflow. The one-step preparation increases proteome coverage relative to the previous multistep workflow while minimizing labor input and the possibility of human error. We also compared sample recovery between previously used microfabricated glass nanowell chips and injection-molded polypropylene chips and found the polypropylene provided improved proteome coverage. Combined, the one-step sample preparation and the polypropylene substrates enabled the identification of an average of nearly 2400 proteins per cell using a standard data-dependent workflow with Orbitrap mass spectrometers. These advances greatly simplify sample preparation for single-cell proteomics and broaden accessibility with no compromise in terms of proteome coverage.
Topics: Humans; Proteome; Proteomics; Polypropylenes; Mass Spectrometry; Specimen Handling
PubMed: 37410391
DOI: 10.1021/jasms.3c00159 -
Bioengineering (Basel, Switzerland) Jul 2023Hard insoles have been proposed to decrease plantar pressure and prevent foot pain and paresthesia due to repetitive loading. The aim of this research was to analyze the...
BACKGROUND
Hard insoles have been proposed to decrease plantar pressure and prevent foot pain and paresthesia due to repetitive loading. The aim of this research was to analyze the effect of three different hard insoles in cycling on healthy subjects.
METHODS
A crossover randomized trial was carried out. The mean age of the subjects was 35 ± 3.19 years, and all of them were men. While the subjects were cycling on a stationary bicycle, their plantar pressure was recorded with nine in-shoe sensors placed in nine specific foot areas to test a standard ethylene-vinyl-acetate 52° Shore A hardness insole, a polypropylene 58° Shore D insole, and a polypropylene 58 Shore D insole with selective aluminum 60 HB Brinell hardness in the metatarsal head and hallux.
RESULTS
The maximum plantar pressure decreased significantly with the polypropylene insole containing selective aluminum in the metatarsal head and hallux areas. The maximum plantar data of the polypropylene aluminum insole in the M2 area (5.56 kgF/cm), fifth metatarsal styloid process (6.48 kgF/cm), M3-M4 area (4.97 kgF/cm), and hallux (8.91 kgF/cm) were of particular interest compared to the other insoles.
CONCLUSIONS
The use of insoles made of polypropylene with aluminum in the metatarsal head and hallux areas decreases the maximum plantar pressure in cycling compared to standard EVA and polypropylene insoles.
PubMed: 37508843
DOI: 10.3390/bioengineering10070816 -
Angewandte Chemie (International Ed. in... Jan 2024Commercial adhesives typically fall into two categories: structural or pressure sensitive. Structural glues rely on covalent bonds formed during curing and provide high...
Commercial adhesives typically fall into two categories: structural or pressure sensitive. Structural glues rely on covalent bonds formed during curing and provide high tensile strength whilst pressure-sensitive adhesives use physical bonding to provide weaker adhesion, but with considerable convenience for the user. Here, a new class of adhesive is presented that is also reversible, with a bond strength intermediate between those of pressure-sensitive and structural adhesives. Complementary water-based formulations incorporating oppositely charged polyelectrolytes form electrostatic bonds that may be reversed through immersion in a low or high pH aqueous environment. This electrostatic adhesive has the advantageous property that it exhibits good adhesion to low-energy surfaces such as polypropylene. Furthermore, it is produced by the emulsion copolymerization of commodity materials, styrene and butyl acrylate, which makes it inexpensive and opens the possibility of industrial production. Bio-based materials have been also integrated into the formulations to further increase sustainability. Moreover, unlike other water-based glues, adhesion does not significantly degrade in humid environments. Because such electrostatic adhesives do not require mechanical detachment, they are appropriate for the large-scale recycling of, e.g., bottle labels or food packaging. The adhesive is also suitable for dismantling components in areas as varied as automotive parts and electronics.
PubMed: 37899307
DOI: 10.1002/anie.202310750 -
Frontiers in Immunology 2023The release of nanoplastics (NPs) in the environment is a significant health concern for long-term exposed humans. Although their usage has certainly revolutionized...
The release of nanoplastics (NPs) in the environment is a significant health concern for long-term exposed humans. Although their usage has certainly revolutionized several application fields, at nanometer size, NPs can easily interact at the cellular level, resulting in potential harmful effects. Micro/Nanoplastics (M/NPs) have a demonstrated impact on mammalian endocrine components, such as the thyroid, adrenal gland, testes, and ovaries, while more investigations on prenatal and postnatal exposure are urgently required. The number of literature studies on the NPs' presence in biological samples is increasing. However, only a few offer a close study on the model environmental NP-immune system interaction exploited by advanced microscopy techniques. The present study highlights substantial morphological and lipid metabolism alterations in human M1 macrophages exposed to labeled polypropylene and polyvinyl chloride nanoparticles (PP and PVC NPs) (20 μg/ml). The results are interpreted by advanced microscopy techniques combined with standard laboratory tests and fluorescence microscopy. We report the accurate detection of polymeric nanoparticles doped with cadmium selenide quantum dots (CdSe-QDs NPs) by following the Se (L line) X-ray fluorescence emission peak at higher sub-cellular resolution, compared to the supportive light fluorescence microscopy. In addition, scanning transmission X-ray microscopy (STXM) imaging successfully revealed morphological changes in NP-exposed macrophages, providing input for Fourier transform infrared (FTIR) spectroscopy analyses, which underlined the chemical modifications in macromolecular components, specifically in lipid response. The present evidence was confirmed by quantifying the lipid droplet (LD) contents in PP and PVC NPs-exposed macrophages (0-100 μg/ml) by Oil Red O staining. Hence, even at experimental NPs' concentrations and incubation time, they do not significantly affect cell viability; they cause an evident lipid metabolism impairment, a hallmark of phagocytosis and oxidative stress.
Topics: Humans; Animals; Female; Pregnancy; Microplastics; Lipid Metabolism; Synchrotrons; Macrophages; Microscopy, Fluorescence; Mammals
PubMed: 37744340
DOI: 10.3389/fimmu.2023.1247747 -
Environment International Nov 2023Irregularly shaped microplastics (MPs) released from infant feeding bottles (PP-IFBs) may exhibit increased cytotoxicity, in contrast to the commonly studied spherical...
Irregularly shaped microplastics (MPs) released from infant feeding bottles (PP-IFBs) may exhibit increased cytotoxicity, in contrast to the commonly studied spherical MPs. This study presents an initial analysis of the thermal-oxidative aging process of plastic shedding from feeding bottles, and investigates the inflammatory response induced by these atypical MPs in human intestinal cells (Caco-2). The PP-IFBs' surface displayed non-uniform white patches and increased roughness, revealing substantial structural alteration and shedding, especially during actions such as shaking, boiling water disinfection, and microwave heating. FT-IR and 2D-COS analyses revealed that oxygen targeted the C-H and C-C bonds of polypropylene molecular chain, producing RO· and ·OH, thereby hastening polypropylene degradation. When human intestinal cells were exposed to MPs from PP-IFBs, oxidative stress was triggered, resulting in lowered glutathione levels, augmented reactive oxygen species (ROS), and heightened lipid peroxidation. Elevated levels of pro-inflammatory cytokines (IL-6 and TNFα) signified an active inflammatory process. The inflammatory response was notably more intense when exposed to MPs released through boiling water disinfection and microwave heating treatments, primarily due to the larger quantity of MPs released and their higher proportion of smaller particles. Furthermore, the NLRP3 inflammasome was identified as critical in initiating this inflammatory chain reaction due to the mitochondrial ROS surge caused by MPs exposure. This was further validated by inhibitor studies, emphasizing the role of the ROS/NLRP3/Caspase-1/IL-1β signaling pathway in in promoting intestinal inflammation. Therefore, swift actions are recommended to protect infants against the potential health effects of MPs exposure.
Topics: Humans; NLR Family, Pyrin Domain-Containing 3 Protein; Plastics; Reactive Oxygen Species; Caspase 1; Microplastics; Caco-2 Cells; Polypropylenes; Spectroscopy, Fourier Transform Infrared; Inflammation; Signal Transduction; Water
PubMed: 37924603
DOI: 10.1016/j.envint.2023.108296 -
International Journal of Molecular... Mar 2024Poly(propylene carbonate) (PPC) is an emerging "carbon fixation" polymer that holds the potential to become a "biomaterial of choice" in healthcare owing to its good... (Review)
Review
Poly(propylene carbonate) (PPC) is an emerging "carbon fixation" polymer that holds the potential to become a "biomaterial of choice" in healthcare owing to its good biocompatibility, tunable biodegradability and safe degradation products. However, the commercialization and wide application of PPC as a biomedical material are still hindered by its narrow processing temperature range, poor mechanical properties and hydrophobic nature. Over recent decades, several physical, chemical and biological modifications of PPC have been achieved by introducing biocompatible polymers, inorganic ions or small molecules, which can endow PPC with better cytocompatibility and desirable biodegradability, and thus enable various applications. Indeed, a variety of PPC-based degradable materials have been used in medical applications including medical masks, surgical gowns, drug carriers, wound dressings, implants and scaffolds. In this review, the molecular structure, catalysts for synthesis, properties and modifications of PPC are discussed. Recent biomedical applications of PPC-based biomaterials are highlighted and summarized.
Topics: Biocompatible Materials; Polymers; Prostheses and Implants; Propane
PubMed: 38474185
DOI: 10.3390/ijms25052938 -
Biomaterials Advances May 2024Currently, in vitro testing examines the cytotoxicity of biomaterials but fails to consider how materials respond to mechanical forces and the immune response to them;...
Currently, in vitro testing examines the cytotoxicity of biomaterials but fails to consider how materials respond to mechanical forces and the immune response to them; both are crucial for successful long-term implantation. A notable example of this failure is polypropylene mid-urethral mesh used in the treatment of stress urinary incontinence (SUI). The mesh was largely successful in abdominal hernia repair but produced significant complications when repurposed to treat SUI. Developing more physiologically relevant in vitro test models would allow more physiologically relevant data to be collected about how biomaterials will interact with the body. This study investigates the effects of mechanochemical distress (a combination of oxidation and mechanical distention) on polypropylene mesh surfaces and the effect this has on macrophage gene expression. Surface topology of the mesh was characterised using SEM and AFM; ATR-FTIR, EDX and Raman spectroscopy was applied to detect surface oxidation and structural molecular alterations. Uniaxial mechanical testing was performed to reveal any bulk mechanical changes. RT-qPCR of selected pro-fibrotic and pro-inflammatory genes was carried out on macrophages cultured on control and mechanochemically distressed PP mesh. Following exposure to mechanochemical distress the mesh surface was observed to crack and craze and helical defects were detected in the polymer backbone. Surface oxidation of the mesh was seen after macrophage attachment for 7 days. These changes in mesh surface triggered modified gene expression in macrophages. Pro-fibrotic and pro-inflammatory genes were upregulated after macrophages were cultured on mechanochemically distressed mesh, whereas the same genes were down-regulated in macrophages exposed to control mesh. This study highlights the relationship between macrophages and polypropylene surgical mesh, thus offering more insight into the fate of an implanted material than existing in vitro testing.
Topics: Humans; Materials Testing; Surgical Mesh; Polypropylenes; Biocompatible Materials; Macrophages; Urinary Incontinence, Stress
PubMed: 38377947
DOI: 10.1016/j.bioadv.2024.213800 -
Arquivos Brasileiros de Cirurgia... 2023In the surgical correction of large incisional hernias, the use of a prosthesis is essential in most cases regardless of the technique chosen. The preference is for the...
BACKGROUND
In the surgical correction of large incisional hernias, the use of a prosthesis is essential in most cases regardless of the technique chosen. The preference is for the polypropylene prosthesis.
AIMS
To compare the onlay and Rives-Stoppa techniques in the correction of incisional hernias, their immediate results, complications, advantages, and disadvantages.
METHODS
Two groups of patients with incisional hernias were analyzed, submitted to the onlay (19 patients) and Rives-Stoppa (17 patients) techniques, and that used polypropylene prostheses. General epidemiological variables, perioperative data variables, and postoperative complications were assessed.
RESULTS
The patients' epidemiologic profile was similar between both groups. The majority were women (58.4%), with a mean age of 65.5 years and a previous mean body mass index of 41.5 kg/m². The Rives-Stoppa technique was employed in most patients (52.7%). Those submitted to the onlay technique had longer abdominal drainage time and longer hospital stay, as well as a higher incidence of seromas and surgical wound infection.
CONCLUSIONS
The incisional herniorrhaphy technique with the placement of a pre-peritoneal polypropylene mesh by the Rives-Stoppa technique was superior to the onlay due to lower rates of drain use, hospital stay, and postoperative complications.
Topics: Humans; Male; Female; Aged; Incisional Hernia; Polypropylenes; Treatment Outcome; Surgical Mesh; Recurrence; Hernia, Ventral; Herniorrhaphy; Postoperative Complications
PubMed: 37851752
DOI: 10.1590/0102-672020230048e1766