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Macromolecular Rapid Communications Oct 2012Using a facile dialysis nanoprecipitation method, nanoparticles of several hundred nanometers have been successfully generated from a "traditional," non-biodegradable...
Using a facile dialysis nanoprecipitation method, nanoparticles of several hundred nanometers have been successfully generated from a "traditional," non-biodegradable polymer, that is, polystyrene. The effect of initial polymer concentration inside the dialysis membrane, as well as the polymer/solvent system and the ionic strength (electrolyte concentration) of the dialysis solution, on nanoparticle size is examined. A nucleation-aggregation mechanism has been provided to explain the observed trends. Furthermore, we determine the zeta potential as a function of ionic strength for the generated nanoparticles and show that anionic charging may be present in the system.
Topics: Anions; Dialysis; Nanoparticles; Osmolar Concentration; Particle Size; Polystyrenes
PubMed: 22836901
DOI: 10.1002/marc.201200335 -
Waste Management (New York, N.Y.) Feb 2017In this work, the objective is to examine a novel approach on the biodegradability of polystyrene is examined. A two-step method for the degradation of polystyrene to...
In this work, the objective is to examine a novel approach on the biodegradability of polystyrene is examined. A two-step method for the degradation of polystyrene to chemically useful products has been devised. Initially, polystyrene is liquefied via a thermal degradation procedure predominantly into styrene monomers at low temperatures and left to cool down. Application of microorganisms in a second step targets the breaking of the polymer into smaller organic molecules. Microorganisms tested were Rhodococcus zopfii stoecker, Enterococcus faecalis, Pseudomonas putida and Salmonella with the last two being the most effective. A third step is required to treat the organic products accordingly. The suggested method exhibits total conversion of polystyrene. While the method has only been examined on a small scale, its potential advantages for the recycling of polystyrene waste, are minimized energy costs due to low temperatures of thermal treatment used and the extremely fast degradation kinetics observed.
Topics: Biodegradation, Environmental; Enterococcus faecalis; Hot Temperature; Polystyrenes; Pseudomonas putida; Recycling; Rhodococcus; Salmonella; Waste Management
PubMed: 27440221
DOI: 10.1016/j.wasman.2016.04.017 -
Analytica Chimica Acta Jul 2018Parabens are used as antimicrobial preservatives in food, cosmetic products and pharmaceuticals regardless of their endocrine disrupting effect. In this study, highly...
Parabens are used as antimicrobial preservatives in food, cosmetic products and pharmaceuticals regardless of their endocrine disrupting effect. In this study, highly selective molecular imprinted polymers (MIPs) were synthesized in submicron-sizes and converted to an SPME fiber coating through electrospinning process in order to determine parabens in water samples. Conversion of MIP to a fiber is achieved via creation of spacial knitting around MIP by polystyrene. The selectivity and extraction ability of the fibers were compared with the commercial fibers and the corresponding non-imprinted polymer (NIP) coated fiber. The coated fiber showed better extraction ability among them. Also, the results revealed that the fiber has better selectivity for benzyl paraben and the other structurally-related compounds, such as methyl and propyl paraben. Extraction efficiency of prepared fibers for three parabens has been tested by spiking bottled, tap and sea water samples. The recoveries changed between 92.2 ± 0.8 and 99.8 ± 0.1 for three different water types. This method could be used for selective and sensitive determination of parabens in aqueous samples.
Topics: Acrylates; Adsorption; Microspheres; Molecular Imprinting; Parabens; Polystyrenes
PubMed: 29523246
DOI: 10.1016/j.aca.2018.02.016 -
Archives of Microbiology Jul 2021The present study approaches the capability of Cephalosporium strain NCIM 1251 to degrade pre-treated polystyrene films. Polystyrene was initially treated with UV for...
The present study approaches the capability of Cephalosporium strain NCIM 1251 to degrade pre-treated polystyrene films. Polystyrene was initially treated with UV for the introduction of oxygen molecules in pure polystyrene samples. UV treatment inserts aliphatic ketones functional group in polystyrene whereas it created C-C stretching after chemical treatment in UV-treated polystyrene as analyzed by Fourier-transform infrared spectroscopy (FTIR). The gravimetric study confirmed a decline in the weight of the pre-treated polystyrene by 20.62 ± 1.47% after 8 weeks of the incubation period. pH, total dissolved solids (TDS), and conductivity of mineral salt media were correlated with the extent of biodegradation. Treatment with UV and acid increased the thermal stability of pure polystyrene, whereas thermal stability decreased in pre-treated polystyrene after incubation with Cephalosporium strain NCIM 1251 as studied by Thermogravimetric analysis (TGA). Scanning Electron Microscopy (SEM) analysis observed revisions in the morphology and surface patterns in pre-treated polystyrene after inoculation with Cephalosporium strain NCIM 1251. The observed findings suggest that the Cephalosporium strain NCIM 1251 could be efficient for the decomposition of pre-treated polystyrene.
Topics: Acremonium; Biodegradation, Environmental; Ketones; Microscopy, Electron, Scanning; Polystyrenes; Spectroscopy, Fourier Transform Infrared; Ultraviolet Rays
PubMed: 33620524
DOI: 10.1007/s00203-021-02228-3 -
The Journal of Physical Chemistry. B Jul 2022Radical polymerization is an economic and practical polymerization method over ionic and coordination polymerizations and is widely used for polymer production. Although...
Radical polymerization is an economic and practical polymerization method over ionic and coordination polymerizations and is widely used for polymer production. Although many efforts have been made to improve the convenience and controllability of radical polymerization, it is still a challenge to directly observe the microbehaviors of propagation, which may provide inspiration for the development of polymerization processes. In this study, we focused on the tacticity of polystyrene produced by bulk radical polymerization since there is a debate over the temperature dependence. The propagation process is simulated Red Moon methodology, which is a cost-effective method for handling complex chemical reaction systems. By the multiple pathway analysis for the propagation reaction model composed of the dimer radical and the monomer using density functional theory, we obtained the relative energies in multiple transition states, whose energy differences are partly explained by the π-π stacking interactions. performing Red Moon simulations from 30 to 190 °C, we confirmed that meso contents moderately increase as the temperature increases, which is explained by the influence of temperature on the probability density of the reaction conformations of each pathway. The successful prediction and explanation for tacticity demonstrate the potential of Red Moon methodology in unveiling the microbehaviors of propagation.
Topics: Polymerization; Polystyrenes; Temperature
PubMed: 35793271
DOI: 10.1021/acs.jpcb.2c02767 -
Journal of Environmental Management Jan 2023Plastic pollution is a major environmental concern due to its deleterious effects on various ecosystems. The limitations and shortcomings of waste management strategies...
Plastic pollution is a major environmental concern due to its deleterious effects on various ecosystems. The limitations and shortcomings of waste management strategies has led to the over-accumulation of plastic waste, mainly comprised of single-use plastics, such as polystyrene (PS). Considering the advantages of biotransformation over the other plastic disposal methods, it has become a major focus of the modern research. Biotransformation of plastics involves its microbial hydrolysis into short chain oligomers and monomers that are eventually assimilated as carbon source by the microbes leading to the release of CO. As fungi are known to possess multifarious and highly regulated enzyme system capable of utilizing diverse nutrient sources, the present study explored the potential of Lichtheimia ramosa AJP11 towards myco-transformation of polystyrene sulfonate (PSS), a structural analogue of polystyrene (PS). During the 30-day incubation period of L. ramosa AJP11 in minimal salt medium (MSM)+1% PSS, the fungus showed 41.6% increment in its fresh weight biomass, indicating the utilization of PSS as sole carbon source. Further analysis revealed the generation of various reaction intermediates such as alkanes and fatty acids, crucial for the continuum of fungal metabolic pathways. Moreover, detection of PS oligomers such as cyclohexane and 2,4-DTBP confirmed the myco-transformation of PSS. The extracellular fungal protein profile showed considerable overexpression of a 14.4 kDa protein, characterized to be a hydrophobic surface binding (Hsb) protein, which is hypothesized to adsorb onto the PSS to facilitate its transformation. Further, in silico analysis of Hsb protein indicated it to be an amphiphilic α-helical protein with ability to bind styrene sulfonate unit via both hydrogen and hydrophobic interactions, with a binding energy of -5.02 kcal mol. These findings open new avenues for over expression of Hsb under controlled reactor conditions to accelerate the PS waste disposal.
Topics: Polystyrenes; Ecosystem; Plastics; Carbon
PubMed: 36302301
DOI: 10.1016/j.jenvman.2022.116579 -
New Biotechnology Sep 2017Large amounts of polystyrene (PS), one of the most widely used plastics in the world, end up in the environment through industrial discharge and littering, becoming one...
Large amounts of polystyrene (PS), one of the most widely used plastics in the world, end up in the environment through industrial discharge and littering, becoming one of the major components of plastic debris. Such plastics, especially the small-sized microplastics and nanoplastics, have received increasing concerns in terms of their potential environmental risks. Feasible approaches for the degradation of PS in waste materials and in the environment are highly desirable. Physicochemical pretreatments of PS may be applied to enhance biological degradation. In the present study, we synthesized C-labelled PS polymers, either uniformly labelled on the ring ([U-ring-C]-PS) or labelled at the β-carbon position of the alkyl chain ([β-C]-PS), and investigated the mineralisation of the C-PS polymers by the fungus Penicillium variabile CCF3219 as well as the effect of ozonation as a physico-chemical pre-treatment on the mineralisation by the fungi. Biodegradation of the C-PS polymers was studied in liquid medium (pH 7.5, without additional carbon substrate) with P. variabile for 16 weeks. During the incubation time, CO was captured to calculate the mineralisation of C-PS and the remaining polymers were analysed by means of scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectrometry and gel-permeation chromatography (GPC). The results showed that the fungi mineralised both labelled polymers, and that the [U-ring-C]-PS with a lower molecular weight led to a higher mineralisation rate. Ozonation pre-treatment strongly enhanced mineralisation of [β-C]-PS. SEM analysis showed that the surface of the ozonated [β-C]-PS became uneven and rough after the incubation, indicating an attack on the polymer by P. variabile. FT-IR analysis showed that ozonation generated carbonyl groups on the [β-C]-PS and the amount of the carbonyl groups decreased after incubation of the [β-C]-PS with P. variabile. GPC analysis showed that the molecular weights of the ozonated [β-C]-PS decreased after incubation. The present data suggest that ozonation pretreatment could be a potential approach for degradation of PS waste and remediation of PS-contaminated sites.
Topics: Biodegradation, Environmental; Carbon Radioisotopes; Ozone; Penicillium; Polystyrenes
PubMed: 27450755
DOI: 10.1016/j.nbt.2016.07.008 -
Journal of Agricultural and Food... Nov 2022Herein, we develop an optical biosensor for highly sensitive and facile detection of ochratoxin A (OTA) using an enzyme-mediated click reaction for signal amplification...
Herein, we develop an optical biosensor for highly sensitive and facile detection of ochratoxin A (OTA) using an enzyme-mediated click reaction for signal amplification and polystyrene nanoparticles (PNPs) for signal readout. Alkaline phosphatase was employed to hydrolyze the ascorbic acid-phosphate to generate ascorbic acid, which reduces Cu(II) to Cu(I). Cu(I) can catalyze the click reaction between alkyne-functionalized magnetic beads and azide-functionalized PNPs to form complexes, while unbound PNPs acted as the signal probe. This strategy utilized the high efficiency of click chemistry and the inherent optical absorption properties of PNPs, which effectively improved the sensitivity of conventional immunoassays and simplified the procedures using magnetic separation technology. This optical biosensor enabled OTA detection in a linear range of 0.1 to 50 ng/mL with a detection limit of 54 pg/mL. Moreover, it has been successfully challenged with OTA detection in maize samples, revealing its potential as a promising tool for mycotoxin screening.
Topics: Polystyrenes; Limit of Detection; Biosensing Techniques; Nanoparticles; Ascorbic Acid
PubMed: 36372964
DOI: 10.1021/acs.jafc.2c05137 -
Langmuir : the ACS Journal of Surfaces... Oct 2015In this work we experimentally and theoretically analyze the detachment of microscopic polystyrene beads from different self-assembled monolayer (SAM) surfaces in a...
In this work we experimentally and theoretically analyze the detachment of microscopic polystyrene beads from different self-assembled monolayer (SAM) surfaces in a shear flow in order to develop a mechanistic model for the removal of cells from surfaces. The detachment of the beads from the surface is treated as a thermally activated process applying an Arrhenius Ansatz to determine the activation barrier and attempt frequency of the rate determing step in bead removal. The statistical analysis of the experimental shear detachment data obtained in phosphate-buffered saline buffer results in an activation energy around 20 kJ/mol, which is orders of magnitude lower than the adhesion energy measured by atomic force microscopy (AFM). The same order of magnitude for the adhesion energy measured by AFM is derived from ab initio calculations of the van der Waals interaction energy between the polystyrene beads and the SAM-covered gold surface. We conclude that the rate determing step for detachment of the beads is the initiation of rolling on the surface (overcoming static friction) and not physical detachment, i.e., lifting the particle off the surface.
Topics: Microscopy, Atomic Force; Polystyrenes; Shear Strength; Surface Properties
PubMed: 26401759
DOI: 10.1021/acs.langmuir.5b02321 -
Drug Discovery Today Mar 2018A recent study on nanoparticle-induced hypersensitivity reactions in pigs showed robust pulmonary intravascular macrophage clearance of Polybead carboxylate microspheres... (Review)
Review
A recent study on nanoparticle-induced hypersensitivity reactions in pigs showed robust pulmonary intravascular macrophage clearance of Polybead carboxylate microspheres in mediating the adverse cardiopulmonary distress, irrespective of the ability of these particles to activate the complement (C) system in vitro. Focusing on this observation, this article highlights the controversies in projecting in vitro C assay data to in vivo conditions and applying data on polystyrene particles to therapeutic nanopharmaceuticals. Based on overwhelming evidence of a role of anaphylatoxins in hypersensitivity reactions, the need to further explore the role of C activation in the reported and other reactions is highlighted. C-activation-related and C-independent pseudoallergies (CARPA and CIPA) can proceed simultaneously, as outlined by the 'double-hit' hypothesis.
Topics: Anaphylatoxins; Animals; Complement Activation; Drug Hypersensitivity; Humans; Microspheres; Nanoparticles; Polystyrenes; Swine
PubMed: 29326077
DOI: 10.1016/j.drudis.2018.01.025