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A small scale field trial with expanded polystyrene beads for mosquito control in septic tanks

Chang MS, Lian S, Jute N

Trans R Soc Trop Med Hyg, 1995 3 1;89(2):140-1.
PMID: 7778135

A field trial of the use of expanded polystyrene beads (EPSB) to control the breeding of mosquito larvae in household septic tanks was conducted in Sarawak. One week after treatment, the breeding of Culex quinquefasciatus and Aedes albopictus was reduced by 100% and 68.7% respectively. For both species combined, a 57.25% reduction in the adult emergence rate was achieved. No adult was caught in the emergence trap one month after treatment. A reduction in mosquito biting rates was reported by 87.3% of respondents. All households regarded the EPSB treatment as effective. This study has reduced the relatively high infestation rate of A. albopictus in the septic tanks to 16-20%. The EPSB treatment is feasible and practical. Post-treatment assessment using adult emergence traps and the implications for the vector control programme of the local authority are discussed.

Matched MeSH terms: Polystyrenes
Fulltext An optical test strip for the detection of benzoic acid in food

Hamzah HH, Yusof NA, Salleh AB, Bakar FA

Sensors (Basel), 2011;11(8):7302-13.
PMID: 22164018 DOI: 10.3390/s110807302

Fabrication of a test strip for detection of benzoic acid was successfully implemented by immobilizing tyrosinase, phenol and 3-methyl-2-benzothiazolinone hydrazone (MBTH) onto filter paper using polystyrene as polymeric support. The sensing scheme was based on the decreasing intensity of the maroon colour of the test strip when introduced into benzoic acid solution. The test strip was characterized using optical fiber reflectance and has maximum reflectance at 375 nm. It has shown a highly reproducible measurement of benzoic acid with a calculated RSD of 0.47% (n = 10). The detection was optimized at pH 7. A linear response of the biosensor was obtained in 100 to 700 ppm of benzoic acid with a detection limit (LOD) of 73.6 ppm. At 1:1 ratio of benzoic acid to interfering substances, the main interfering substance is boric acid. The kinetic analyses show that, the inhibition of benzoic is competitive inhibitor and the inhibition constant (K(i)) is 52.9 ppm. The activity of immobilized tyrosinase, phenol, and MBTH in the test strip was fairly sustained during 20 days when stored at 3 °C. The developed test strip was used for detection of benzoic acid in food samples and was observed to have comparable results to the HPLC method, hence the developed test strip can be used as an alternative to HPLC in detecting benzoic acid in food products.

Matched MeSH terms: Polystyrenes/chemistry
Fulltext Analysis of shotcrete lining of underground tunnels

Ghiasi, Vahed, Husaini Omar

Pertanika Journal of Science & Technology, 2011;19(2):249-257.
MyJurnal

Shotcrete is a process where concrete is projected or “shot” under pressure, using a feeder or a
“gun” onto a surface to form structural shapes including walls, floors, and roofs. The surface can
be wood, steel, polystyrene, or any other surfaces that concrete can be projected onto. The surface
can be trowel led smooth while the concrete is still wet. Shotcrete has high strength, durability, low
permeability, excellent bond, and limitless shape possibilities. These properties allow shotcrete
to be used as a structural material in most cases. Although the hardened properties of shotcrete
are similar to conventional cast-in-place concrete, the nature of the placement process provides
additional benefits, such as excellent bond with most substrates and instant or rapid capabilities,
particularly on complex forms or shapes. In addition to building homes, shotcrete can also be used
to build pools. The practice of underground tunneling shows that the degree of stability of tunnels
is dependent on the state of the soil, rock mass, and shotcrete around the tunnel contour. The
development in the urban or suburban areas leads to the construction of tunnels in all kinds of soil
and rock. Meanwhile, the construction of tunnels in shallow depth or soft soils causes the ground
to displace. The determination of soil and rock mechanical properties to assess the stability of New
Austrian Tunnelling Method (NATM) tunnels and design the support system is one of the most
important steps in tunnelling. This paper provides information pertaining to the safety and increase
the stability of NATM tunnel before, during and after the operation of the tunnel. Therefore, the
shotcrete process is a recognized method for cemented sandy silt stabilization, with the aid of high
pressure shot concrete to increase the stability of tunnels.

Matched MeSH terms: Polystyrenes
Fulltext Assessing biofilm formation by Listeria monocytogenes

Fouladynezhad, N., Afsah-Hejri, L., Rukayadi, Y., Abdulkarim, S.M., Son, R., Marian, M.N.

International Food Research Journal, 2013;20(2):987-990.
MyJurnal

Listeria monocytogenes (L. monocytogenes) is a serious food-borne pathogen for immunocompromised individuals. L. monocytogenes is capable of producing biofilm on the surface of food processing lines and instruments. The biofilm transfers contamination to food products and impose risk to public health. Transfers contamination to food products, and impose risk hazard to public health. The aim of this study was to investigate biofilm producing ability of L. monocytogenes isolates. Microtitre assay was used to measure the amount of biofilm production by ten L. monocytogenes isolates from minced chicken / meat, sausages and burgers. Results showed that all 10 L. monocytogenes isolates were able to form biofilm after 24 h at 20˚C on polystyrene surface (the common surface in food industries). Some strains were capable of forming biofilm more than the others. All strains showed a slight raise in the quantities of attached cells over 48 and 72 h. L. monocytogenes strains isolated from minced chicken, minced meat and burgers were better biofilm-producers comparing to the strains isolated from sausages.

Matched MeSH terms: Polystyrenes
Fulltext Attachment, Proliferation, and Morphological Properties of Human Dermal Fibroblasts on Ovine Tendon Collagen Scaffolds: A Comparative Study

Busra FM, Lokanathan Y, Nadzir MM, Saim A, Idrus RBH, Chowdhury SR

Malays J Med Sci, 2017 Mar;24(2):33-43.
PMID: 28894402 DOI: 10.21315/mjms2017.24.2.5

INTRODUCTION: Collagen type I is widely used as a biomaterial for tissue-engineered substitutes. This study aimed to fabricate different three-dimensional (3D) scaffolds using ovine tendon collagen type I (OTC-I), and compare the attachment, proliferation and morphological features of human dermal fibroblasts (HDF) on the scaffolds.
METHODS: This study was conducted between the years 2014 to 2016 at the Tissue Engineering Centre, UKM Medical Centre. OTC-I was extracted from ovine tendon, and fabricated into 3D scaffolds in the form of sponge, hydrogel and film. A polystyrene surface coated with OTC-I was used as the 2D culture condition. Genipin was used to crosslink the OTC-I. A non-coated polystyrene surface was used as a control. The mechanical strength of OTC-I scaffolds was evaluated. Attachment, proliferation and morphological features of HDF were assessed and compared between conditions.
RESULTS: The mechanical strength of OTC-I sponge was significantly higher than that of the other scaffolds. OTC-I scaffolds and the coated surface significantly enhanced HDF attachment and proliferation compared to the control, but no differences were observed between the scaffolds and coated surface. In contrast, the morphological features of HDF including spreading, filopodia, lamellipodia and actin cytoskeletal formation differed between conditions.
CONCLUSION: OTC-I can be moulded into various scaffolds that are biocompatible and thus could be suitable as scaffolds for developing tissue substitutes for clinical applications and in vitro tissue models. However, further study is required to determine the effect of morphological properties on the functional and molecular properties of HDF.

Matched MeSH terms: Polystyrenes
Change in energy-consuming strategy, nucleolar metabolism and physical defense in Macrobrachium rosenbergii after acute and chronic polystyrene nanoparticles exposure

Liang J, Abdullah ALB, Wang H, Liu G, Han M

Aquat Toxicol, 2023 Oct;263:106711.
PMID: 37783050 DOI: 10.1016/j.aquatox.2023.106711

The COVID-19 pandemic has further intensified plastic pollution due to the escalated use of single-use gloves and masks, consequently leading to the widespread presence of microplastics (MPs) and nanoplastics (NPs) in major rivers and lakes worldwide. Macrobrachium rosenbergii has become an important experimental subject due to its ecological role and environmental sensitivity. In this study, we sought to comprehend the ramifications of NPs on the widely-distributed freshwater prawn, M rosenbergii, by conducting a detailed analysis of its responses to NPs after both 96 h and 30 days of exposure. The transcriptome analysis revealed 918 differentially expressed unigenes (DEGs) after 30 days of NPs exposure (356 upregulated, 562 downregulated) and 2376 DEGs after 96 h of NPs exposure (1541 upregulated, 835 downregulated). The results of DEGs expression indicated that acute NPs exposure enhanced carbohydrate transport and metabolism, fostering chitin and extracellular matrix processes. In contrast, chronic NPs exposure induced nucleolar stress in M. rosenbergii, impeding ribosome development and mRNA maturation while showing no significant changes in glucose metabolism. Our findings underscore the M. rosenbergii distinct coping mechanisms during acute and chronic NPs exposure, elucidating its vital adaptive strategies. These results contribute to our understanding of the ecological implications of NPs pollution and its impact on aquatic animals.

Matched MeSH terms: Polystyrenes/toxicity
Chemical modification of chitin by grafting with polystyrene using ammonium persulfate initiator

Abu Naim A, Umar A, Sanagi MM, Basaruddin N

Carbohydr Polym, 2013 Nov 6;98(2):1618-23.
PMID: 24053848 DOI: 10.1016/j.carbpol.2013.07.054

Chitin was successfully grafted with polystyrene by free radical mechanism using ammonium persulfate (APS) initiator. The reaction was carried out in aqueous medium. The effect of pH, chitin:monomer weight ratio, APS, reaction time and reaction temperature were investigated. The results showed that the optimum conditions for grafting of polystyrene were found as follows: pH 7, chitin:monomer weight ratio of 1:3, 0.4 g of APS, reaction temperature of 60 °C and reaction time 2 h. The graft copolymer was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA) and differential scanning electron microscopy (DSC). Gel permeation chromatography (GPC) analysis carried out on the hydrolyzed graft copolymer showed that the Mn and Mw were 6.3395×10(4) g/mol and 1.69283×10(5) g/mol, respectively, with polydispersity index of 2.7.

Matched MeSH terms: Polystyrenes/chemistry*
Fulltext Chromatographic fingerprint and Chemometric approach for quality control of Tongkat Ali (Eurycoma Longifolia)

Nor Nasriah Zaini, Mardiana Saaid, Hafizan Juahir, Rozita Osman

Pertanika Journal of Science & Technology, 2017;25(103):345-354.
MyJurnal

Tongkat Ali (Eurycoma longifolia) is one of the most popular tropical herbal plants as it is believed to enhance virility and sexual prowess. This study looked examined chromatographic fingerprint of Tongkat Ali roots and its products generated using online solid phase-extraction liquid chromatography (SPE-LC) combined with chemometric approaches. The aim was to determine its quality. Pressurised liquid extraction (PLE) technique was used prior to online SPE-LC using polystyrene divinyl benzene (PSDVB) and C18 columns. Seventeen Tongkat Ali roots and 10 products (capsules) were analysed. Chromatographic dataset was subjected to chemometric techniques, namely cluster analysis (CA), discriminant analysis (DA) and principal component analysis (PCA) using 37 selected peaks. The samples were grouped into three clusters based on their quality. The PCA resulted in 11 latent factors describing 90.8% of the whole variance. Pattern matching analysis showed no significant difference (p>0.05) between the roots and products within the same CA grouping. The findings showed the combination of chromatographic fingerprint and chemometric techniques provided comprehensive evaluation for efficient quality control of Tongkat Ali formulation.

Matched MeSH terms: Polystyrenes
Fulltext Colour vision of workers in the plastics industry

Kaur S, Mursyid A, Ariffin AE

Journal of Occupational Safety and Health, 2004;1(1):25-30.
MyJurnal

A study was undertaken to determine the effect of polyethylene and polystyrene used in the manufacture of plastic items on colour perception. Colour vision was assessed using the Ishihara plates, panel 015 test and the Farnsworth Munsell 100-Hue test. Two factories were chosen at random. One factory (referred here as factory A) used virgin resin in pellet form (polyethylene) in the manufacturing of plastic containers to store consumer edible oil. The other factory (referred as factory B) used polystyrene to make plastic bags. A total of 39 healthy employees from factory A (mean age 26.4 :t 8.2 years) and 40 healthy employees from factory B (mean age 26.8 :t 9.6 years) were recruited in this study. A control group of 27 normal healthy subjects (mean age 27.4 :t 4.3 years) who were employees of UKM with no occupational involvement with petroleum derivatives were also recruited in this study and they performed the same colour vision tests. All subjects passed the Ishihara plates test showing that none of the subjects (employees of factory A and B, and control subjects) had a congenital red-green defect. All control subjects passed all of the colour vision tests whilst some employees of factories A and B failed the 015 and FM100 Hue tests. For employees from factory A results from the 015 test showed that 7 (17.9%) had a tritan (blue-yellow) type of defect and 1 (2.6%) had a complex type of defect. The FM 100 Hue results of factory A employees showed that 51.3% (n=20) had a complex type of defect. Total error scores (TES) calculated from the FM 100 Hue test revealed that employees from factory A had a statistically significant higher mean TES of 65.13:!: 48.31 compared to that of control subjects with a mean TES of 31.26:!: 14.93. For employees in factory B, 10 employees (25.0%) had a tritan (blue-yellow) type of defect and 2 (5.0%) had a complex type of defect. Results of the FM 100 Hue test showed that 4 employees (1.0%) had a tritan type of defect whereas 22 (55.0%) had a complex type of defect. Mean total error scores (TES) calculated from the FM 100 Hue test revealed that employees from factory B had a statistically significant higher mean TES of 71.54 :t 54.63 compared with that of control subjects with a mean TES of 31.26 :t. 14.93

The above results show that employees of the plastic factories studies are associated with a higher risk of acquiring colour vision defects as compared to normal subjects who are not engaged in the plastic manufacturing industry. This may have an implication towards the future retinal health of employees in petrod1emical-based industries.

Matched MeSH terms: Polystyrenes
Combined effects of norfloxacin and polystyrene nanoparticles on the oxidative stress and gut health of the juvenile horseshoe crab Tachypleus tridentatus

Huang M, Ma Y, Qian J, Sokolova IM, Zhang C, Waiho K, et al.

J Hazard Mater, 2024 Apr 15;468:133801.
PMID: 38377908 DOI: 10.1016/j.jhazmat.2024.133801

Pollution with anthropogenic contaminants including antibiotics and nanoplastics leads to gradual deterioration of the marine environment, which threatens endangered species such as the horseshoe crab Tachypleus tridentatus. We assessed the potential toxic mechanisms of an antibiotic (norfloxacin, 0, 0.5, 5 μg/L) and polystyrene nanoparticles (104 particles/L) in T. tridentatus using biomarkers of tissue redox status, molting, and gut microbiota. Exposure to single and combined pollutants led to disturbance of redox balance during short-term (7 days) exposure indicated by elevated level of a lipid peroxidation product, malondialdehyde (MDA). After prolonged (14-21 days) exposure, compensatory upregulation of antioxidants (catalase and glutathione but not superoxide dismutase) was observed, and MDA levels returned to the baseline in most experimental exposures. Transcript levels of molting-related genes (ecdysone receptor, retinoic acid X alpha receptor and calmodulin A) and a molecular chaperone (cognate heat shock protein 70) showed weak evidence of response to polystyrene nanoparticles and norfloxacin. The gut microbiota T. tridentatus was altered by exposures to norfloxacin and polystyrene nanoparticles shown by elevated relative abundance of Bacteroidetes. At the functional level, evidence of suppression by norfloxacin and polystyrene nanoparticles was found in multiple intestinal microbiome pathways related to the genetic information processing, metabolism, organismal systems, and environmental information processing. Future studies are needed to assess the physiological and health consequences of microbiome dysbiosis caused by norfloxacin and polystyrene nanoparticles and assist the environmental risk assessment of these pollutants in the wild populations of the horseshoe crabs.

Matched MeSH terms: Polystyrenes/toxicity
Combined toxic effects of nanoplastics and norfloxacin on antioxidant and immune genes in mussels

Ma Y, Gao Y, Xu R, Li D, Waiho K, Wang Y, et al.

Mar Environ Res, 2024 Jan;193:106277.
PMID: 38040551 DOI: 10.1016/j.marenvres.2023.106277

Nanoplastics (NPs) and antibiotics (ABs) are two of the emerging marine contaminants that have drawn the most attention in recent years. Given the necessity of figuring out the effects of plastic and antibiotic contamination on marine organism life and population in the natural environment, it is essential to apply rapid and effective biological indicators to evaluate their comprehensive toxic effects. In this study, using mussel (Mytilus coruscus) as a model, we investigated the combined toxic effects of NP (80 nm polystyrene beads) and AB (Norfloxacin, NOR) at environmental-relevant concentrations on antioxidant and immune genes. In terms of the antioxidant genes, NPs significantly increased the relative expression of Cytochrome P450 3A-1 (CYP3A-1) under various concentrations of NOR conditions, but they only significantly increased the relative expression of CYP3A-2 in the high concentration (500 μg L-1 NOR) co-exposure group. In the NP-exposure group which exposed to no or low concentrations of NOR, nuclear factor erythroid 2-related factor 2 (Nrf2) was upregulated. In terms of the immune genes, interleukin-1 receptor-associated kinase (IRAK) -1 showed a significant increase in the low-concentration NOR group while a significant inhibition in the high-concentration NOR group. Due to the presence of NPs, exposure to NOR resulted in a significant increase in both IRAK-4 and heat shock protein (HSP) 70. Our findings indicate that polystyrene NPs can exacerbate the effects of NOR on the anti-oxidant and immune defense performance of mussels. This study delves into the toxic effects of NPs and ABs from a molecular perspective. Given the expected increase in environmental pollution due to NPs and ABs, future research is needed to investigate the potential synergistic effect of NPs and ABs on other organisms.

Matched MeSH terms: Polystyrenes/toxicity
Conductive PEDOT:PSS coated polylactide (PLA) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) electrospun membranes: Fabrication and characterization

Chang HC, Sun T, Sultana N, Lim MM, Khan TH, Ismail AF

Mater Sci Eng C Mater Biol Appl, 2016 Apr 1;61:396-410.
PMID: 26838866 DOI: 10.1016/j.msec.2015.12.074

In the current study, electrospinning technique was used to fabricate composite membranes by blending of a synthetic polymer, polylactic acid (PLA) and a natural polymer, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), PHBV. Conductive membranes were prepared by dipping PLA/PHBV electrospun membranes into poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (

Matched MeSH terms: Polystyrenes/chemistry*
Continuous harvest of stem cells via partial detachment from thermoresponsive nanobrush surfaces

Peng IC, Yeh CC, Lu YT, Muduli S, Ling QD, Alarfaj AA, et al.

Biomaterials, 2016 Jan;76:76-86.
PMID: 26519650 DOI: 10.1016/j.biomaterials.2015.10.039

Stem cell culture is typically based on batch-type culture, which is laborious and expensive. Here, we propose a continuous harvest method for stem cells cultured on thermoresponsive nanobrush surfaces. In this method, stem cells are partially detached from the nanobrush surface by reducing the temperature of the culture medium below the critical solution temperature needed for thermoresponse. The detached stem cells are harvested by exchange into fresh culture medium. Following this, the remaining cells are continuously cultured by expansion in fresh culture medium at 37 °C. Thermoresponsive nanobrush surfaces were prepared by coating block copolymers containing polystyrene (for hydrophobic anchoring onto culture dishes) with three types of polymers: (a) polyacrylic acid with cell-binding oligopeptides, (b) thermoresponsive poly-N-isopropylacrylamide, and (c) hydrophilic poly(ethyleneglycol)methacrylate. The optimal coating durations and compositions for these copolymers to facilitate adequate attachment and detachment of human adipose-derived stem cells (hADSCs) and embryonic stem cells (hESCs) were determined. hADSCs and hESCs were continuously harvested for 5 and 3 cycles, respectively, via the partial detachment of cells from thermoresponsive nanobrush surfaces.

Matched MeSH terms: Polystyrenes
Control of Attachment of Pseudomonas aeruginosa and Burkholderia cepacia to Surfaces by Shear Force

Hui YW, Narayanan K, Dykes GA

Water Environ Res, 2016 Nov 01;88(11):2040-2046.
PMID: 26704787 DOI: 10.2175/106143016X14504669767292

The effect of physical shearing on the attachment of six Pseudomonas aeruginosa strains and six Burkholderia cepacia strains to glass, stainless steel, polystyrene and Teflon® was determined. A significant (p < 0.05) decrease in hydrophobicity was apparent for all P. aeruginosa strains (17-36%) and B. cepacia, MS 5 (20%) after shearing. A significant (p < 0.05) decrease in attachment of some P. aeruginosa (0.2-0.5 log CFU/cm2) and B. cepacia (0.2-0.4 log CFU/cm2) strains to some surface types was apparent after shearing. Significant (p < 0.05) correlation was observed for both numbers of flagellated cells and hydrophobicity against attachment to glass, stainless steel and polystyrene for P. aeruginosa while only hydrophobicity showed significant correlation against the same surfaces for B. cepacia. Scanning electron microscopy and protein analysis showed that shearing removed surface proteins from the cells and may have led to the observed changes in hydrophobicity and attachment to abiotic surfaces.

Matched MeSH terms: Polystyrenes
Fulltext Curcuma longa rhizome extract and Curcumin reduce the adhesion of Acanthamoeba triangularis trophozoites and cysts in polystyrene plastic surface and contact lens

Mitsuwan W, Sangkanu S, Romyasamit C, Kaewjai C, Jimoh TO, de Lourdes Pereira M, et al.

Int J Parasitol Drugs Drug Resist, 2020 12;14:218-229.
PMID: 33238231 DOI: 10.1016/j.ijpddr.2020.11.001

Curcuma longa and Curcumin have been documented to have a wide spectrum of pharmacological effects, including anti-Acanthamoeba activity. Hence, this study sought to explore the anti-adhesion activity of C. longa extract and Curcumin against Acanthamoeba triangularis trophozoites and cysts in plastic and contact lenses. Our results showed that C. longa extract and Curcumin significantly inhibited the adhesion of A. triangularis trophozoites and cysts to the plastic surface, as investigated by the crystal violet assay (P

Matched MeSH terms: Polystyrenes
Fulltext Data of continuous harvest of stem cells via partial detachment from thermoresponsive nanobrush surfaces

Yeh CC, Muduli S, Peng IC, Lu YT, Ling QD, Alarfaj AA, et al.

Data Brief, 2016 Mar;6:603-8.
PMID: 26909373 DOI: 10.1016/j.dib.2015.12.056

This data article contains two figures and one table supporting the research article entitled: "Continuous harvest of stem cells via partial detachment from thermoresponsive nanobrush surface" [1]. The table shows coating conditions of three copolymers, poly(styrene-co-acrylic acid) grafted with oligovitronectin, poly(styrene-co-N-isopropylacrylamide) and poly(styrene-co-polyethylene glycol methacrylate) to prepare thermoresponsive surface. XPS spectra show the nitrogen peak of the polystyrene surface coated with poly(styrene-co-acrylic acid) grafted with oligovitronectin. The surface coating density analyzed from sorption of poly(styrene-co-acrylic acid) grafted with oligovitronectin by UV-vis spectroscopy is also presented.

Matched MeSH terms: Polystyrenes
Development of an Hg(II) fibre-optic sensor for aqueous environmental monitoring

Ahmad M, Hamzah H, Sufliza Marsom E

Talanta, 1998 Oct;47(2):275-83.
PMID: 18967326

An optical sensor for Hg(II) monitoring using a complex of zinc dithizonate immobilised on XAD 7 which is based on reflectance spectrophotometry has been developed in this study. Measurements were made using a kinetic approach whereby the reflectance signal is measured at a fixed time of 5 min. The sensor could be regenerated using a saturated solution of KCl in 1 M sulphuric acid. The sensor was found to have an optimum response at pH 3.0 with respective measurement repeatability and probe-to-probe reproducibility of 1.53% and 5.26%. A linear response was observed in the Hg(II) concentration range of 0.0-180.0 ppm with a calculated limit of detection (LOD) of 0.05 ppm. The results obtained for aqueous Hg(II) determination using this probe were found to be comparable with the well-established method of atomic absorption spectrometry.

Matched MeSH terms: Polystyrenes
Fulltext Dielectrophoresis Prototypic Polystyrene Particle Synchronization toward Alive Keratinocyte Cells for Rapid Chronic Wound Healing

Deivasigamani R, Maidin NNM, Wee MFMR, Mohamed MA, Buyong MR

Sensors (Basel), 2021 Apr 25;21(9).
PMID: 33922993 DOI: 10.3390/s21093007

Diabetes patients are at risk of having chronic wounds, which would take months to years to resolve naturally. Chronic wounds can be countered using the electrical stimulation technique (EST) by dielectrophoresis (DEP), which is label-free, highly sensitive, and selective for particle trajectory. In this study, we focus on the validation of polystyrene particles of 3.2 and 4.8 μm to predict the behavior of keratinocytes to estimate their crossover frequency (fXO) using the DEP force (FDEP) for particle manipulation. MyDEP is a piece of java-based stand-alone software used to consider the dielectric particle response to AC electric fields and analyzes the electrical properties of biological cells. The prototypic 3.2 and 4.8 μm polystyrene particles have fXO values from MyDEP of 425.02 and 275.37 kHz, respectively. Fibroblast cells were also subjected to numerical analysis because the interaction of keratinocytes and fibroblast cells is essential for wound healing. Consequently, the predicted fXO from the MyDEP plot for keratinocyte and fibroblast cells are 510.53 and 28.10 MHz, respectively. The finite element method (FEM) is utilized to compute the electric field intensity and particle trajectory based on DEP and drag forces. Moreover, the particle trajectories are quantified in a high and low conductive medium. To justify the simulation, further DEP experiments are carried out by applying a non-uniform electric field to a mixture of different sizes of polystyrene particles and keratinocyte cells, and these results are well agreed. The alive keratinocyte cells exhibit NDEP force in a highly conductive medium from 100 kHz to 25 MHz. 2D/3D motion analysis software (DIPP-MotionV) can also perform image analysis of keratinocyte cells and evaluate the average speed, acceleration, and trajectory position. The resultant NDEP force can align the keratinocyte cells in the wound site upon suitable applied frequency. Thus, MyDEP estimates the Clausius-Mossotti factors (CMF), FEM computes the cell trajectory, and the experimental results of prototypic polystyrene particles are well correlated and provide an optimistic response towards keratinocyte cells for rapid wound healing applications.

Matched MeSH terms: Polystyrenes*
Fulltext Dielectrophoretic manipulation and separation of microparticles using microarray dot electrodes

Yafouz B, Kadri NA, Ibrahim F

Sensors (Basel), 2014;14(4):6356-69.
PMID: 24705632 DOI: 10.3390/s140406356

This paper introduces a dielectrophoretic system for the manipulation and separation of microparticles. The system is composed of five layers and utilizes microarray dot electrodes. We validated our system by conducting size-dependent manipulation and separation experiments on 1, 5 and 15 μm polystyrene particles. Our findings confirm the capability of the proposed device to rapidly and efficiently manipulate and separate microparticles of various dimensions, utilizing positive and negative dielectrophoresis (DEP) effects. Larger size particles were repelled and concentrated in the center of the dot by negative DEP, while the smaller sizes were attracted and collected by the edge of the dot by positive DEP.

Matched MeSH terms: Polystyrenes/chemistry*
Dietary polystyrene nanoplastics exposure alters hepatic glycolipid metabolism, triggering inflammatory responses and apoptosis in Monopterus albus

Zhu C, Zhou W, Han M, Yang Y, Li Y, Jiang Q, et al.

Sci Total Environ, 2023 Sep 15;891:164460.
PMID: 37247739 DOI: 10.1016/j.scitotenv.2023.164460

Microplastics and nanoplastics (MPs and NPs) are abundant, persistent, and widespread environmental pollutants that are of increasing concern as they pose a serious threat to ecosystems and aquatic species. Identifying the ecological effects of NPs pollution requires understanding the effects of changing nanoplastics concentrations in aquatic organisms. Monopterus albus were orally fed three different concentrations of 100 nm polystyrene nanoplastics (PS-NPs): 0.05 %, 0.5 %, and 1 % of the feed for 28 days. Nanoplastics significantly activated the PPAR signaling pathway, Acyl-CoA oxidase 1 (ACOX1), carnitine palmitoyltransferase 1a (CPT1A), angiopoietin-like 4 (ANGPTL4), and phosphoenolpyruvate carboxykinase (PCK) at the mRNA level, resulting in disturbed lipid metabolism. Glutathione peroxidase (GSH-px) activity, catalase (CAT) activity, and malondialdehyde (MDA) were significantly elevated in the high nanoplastics-feeding exposure group, leading to oxidative stress in the liver. Overexpression of the cytokines genes Interleukin 1 (IL1B) and Interleukin-8 (IL8), Tumor necrosis factor alpha (TNF-α), activation of MAPK signaling pathway, and increased gene expression of c-Jun amino-terminal kinases (JNK) and p38 indicate that exposure to NPs may lead to hepatopancreas apoptosis through oxidative stress and inflammation. In summary, dietary PS-NPs exposure alters hepatic glycolipid metabolism, triggering inflammatory responses and apoptosis in M. albus. The results of this study provide valuable ecotoxicological data for a better understanding of the biological fate and effects of nanoplastics in M. albus.

Matched MeSH terms: Polystyrenes/toxicity

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