Polystyrene Beads Research Articles

Microplastics impede larval urchin selective feeding.

Microplastics are emergent threats to marine organisms as ingestion can cause a multitude of physiological problems. Suspension feeders, including marine invertebrate larvae, are particularly susceptible to ingesting microplastics due to similarities in physical appearance to algal cells. Larval feeding involves multiple stages: the capture and subsequent selection of particles followed by ingestion from the mouth to the stomach, digestion, and finally, egestion. Yet, little is known about which aspect of the feeding process is disrupted by microplastics. Here, we determine if prior exposure to microplastics alters the feeding behavior of the larval sea urchin Heliocidaris crassispina. We conducted two experiments: a food handling experiment studied larval survival, growth, and time required to fill and vacate the stomach; and a particle selection experiment analyzed changes in the ability of the larvae to selectively ingest algal cells over microplastics. In both experiments, larvae were pre-exposed to algae only (control), the addition of 10 μm polystyrene beads at 1 bead mL-1 or 1000 beads mL-1 until 3- or 7-days post-fertilization. Previous exposure to microplastics lengthened stomach filling time and impaired particle selection. While there was no significant change in survivorship and larval arm length, these sub-lethal impacts on larval feeding likely have more severe ramifications in vivo where food is limited, and thus, potentially threaten post-settlement success.

Electrosynthesized nanostructured molecularly imprinted polymer for detecting diclofenac molecule

• Effective technique to generate nanostructured polymer on glassy carbon electrodes. • Micropatterned molecular imprinted polymer film for detecting diclofenac. • A cavity-confined electrochemical growth of PEDOT in the presence of DCF. • Simultaneous extraction of PS beads and DCF by dipping in THF solution at once. • A larger active surface decorated GC provides more accessible binding sites. This work describes the preparation and application of micropatterned molecular imprinting in conductive polymer film for the detection of diclofenac molecules. A fast and cost-effective technique for generating nanostructured polymer on glassy carbon electrode (GCE) by combining nanosphere lithography (NSL) and electrochemical polymerization is reported. Firstly, GCE is modified by a close-packed monolayer of polystyrene (PS) spheres sized 500 nm in diameter, which subsequently serves as a template for the electrochemical deposition of poly(3,4-ethylene dioxythiophene) (PEDOT) accompanied by diclofenac (DCF). The functional monomers of 3,4-ethylene dioxythiophene (EDOT) were electropolymerized in the presence of sodium diclofenac (DCF-Na) as a target molecule to prepare a molecularly imprinted polymer (MIP) electrode. After dissolving PS and DCF-templated molecules simultaneously in tetrahydrofuran (THF) solvent, the micropatterned structure of PEDOT is generated on the GCE surface. This as-prepared MIP surface is applied to test the recognition of DCF molecules in phosphate-buffered saline (PBS) solution. Good linearity of peak current recorded by differential pulse voltammograms (DVP) after exposure to different DCF concentrations was obtained with a limit of detection (LOD) of 77.5 nM. The sensitivity of the as-prepared MIP electrode is 5 times larger than that of the control electrode made by non-molecular imprinted polymer (NIP). It opens a pathway to significantly improve the sensitivity and the quality of conventional electrochemical sensors for the detection of Diclofenac.

Assessment of the Hydraulic Characteristics of Aggregate-Expanded Polystyrene Beads Composite Using Enhanced Standard Proctor Compaction Test Configuration

Assessment of the Hydraulic Characteristics of Aggregate-Expanded Polystyrene Beads Composite Using Enhanced Standard Proctor Compaction Test Configuration

Structural Behaviour of Polystyrene Foam Lightweight Concrete Beams Strengthened with FRP Laminates

Lightweight concrete (LWC) is one of the most important building materials nowadays. Many research studies were focused on LWC produced using lightweight aggregates. However, limited work was cited for LWC produced using polystyrene beads. In this study, LWC beams strengthened with carbon fibre reinforced polymer (CFRP) and glass fibre reinforced polymer (GFRP) were experimentally tested to investigate the improvement in their flexural and shear behaviours. LWC in this investigation was achieved by partial replacement of normal aggregate by polystyrene beads and resulted in approximately 30% less weight compared to Normal weight concrete. Fourteen Reinforced Concrete (RC) LWC beams of 100 mm by 300 mm cross section having an overall length of 3250 mm were tested under four-point bending. These beams were designed, detailed, and tested to obtain flexural and shear mode of failure. These beams were divided into two groups based on the intended failure mode. In each group, six beams were strengthened using CFRP and GFRP laminates, while the remaining one beam was used as control. The tested parameters were the type of FRP, the width of the laminates used in shear strengthening, and the number of layers used in flexural strengthening. It was found that strengthening of LWC beams using CFRP and GFRP layers resulted in increasing the loading capacity and decreasing deflection as compared to control. The strengthening with CFRP and GFRP is also suitable in reducing the crack width and crack propagation which is more significant in LWC beams. The experimental results were also compared with the expressions in codes for forecasting the strength of LWC beams and it was that these expressions are compatible with the experimental results.

Assessing the toxicity of polystyrene beads and silica particles on the microconsumer Brachionus calyciflorus at different timescales

Environmental pollution by microplastics has become a severe problem in terrestrial and aquatic ecosystems and, according to actual prognoses, problems will further increase in the future. Therefore, assessing and quantifying the risk for the biota is crucial. Standardized short-term toxicological procedures as well as methods quantifying potential toxic effects over the whole life span of an animal are required. We studied the effect of the microplastic polystyrene on the survival and reproduction of a common freshwater invertebrate, the rotifer Brachionus calyciflorus, at different timescales. We used pristine polystyrene spheres of 1, 3, and 6 µm diameter and fed them to the animals together with food algae in different ratios ranging from 0 to 50% nonfood particles. As a particle control, we used silica to distinguish between a pure particle effect and a plastic effect. After 24 h, no toxic effect was found, neither with polystyrene nor with silica. After 96 h, a toxic effect was detectable for both particle types. The size of the particles played a negligible role. Studying the long-term effect by using life table experiments, we found a reduced reproduction when the animals were fed with 3 µm spheres together with similar-sized food algae. We conclude that the fitness reduction is mainly driven by the dilution of food by the nonfood particles rather than by a direct toxic effect.

Fabrication of Nylon-6 and Nylon-11 Nanoplastics and Evaluation in Mammalian Cells.

Microplastics (MPs) and nanoplastics (NPs) exist in certain environments, beverages, and food products. However, the ultimate risk and consequences of MPs and NPs on human health remain largely unknown. Studies involving the biological effects of small-scale plastics have predominantly used commercially available polystyrene beads, which cannot represent the breadth of globally dominant plastics. Nylon is a commodity plastic that is used across various industry sectors with substantial global production. Here, a series of well-characterized nylon-11 and nylon-6 NPs were successfully fabricated with size distributions of approximately 100 nm and 500 nm, respectively. The facile fabrication steps enabled the incorporation of fluorescent tracers in these NPs to aid the intracellular tracking of particles. RAW 264.7 macrophages were exposed to nylon NPs in a dose-dependent manner and cytotoxic concentrations and cellular uptake were determined. These well-characterized nylon NPs support future steps to assess how the composition and physicochemical properties may affect complex biological systems and ultimately human health.

Rapid Detection of Urinary Tract Infection in 10 min by Tracking Multiple Phenotypic Features in a 30 s Large-Volume Scattering Video of Urine Microscopy.

Rapid point-of-care (POC) diagnosis of bacterial infection diseases provides clinical benefits of prompt initiation of antimicrobial therapy and reduction of the overuse/misuse of unnecessary antibiotics for nonbacterial infections. We present here a POC compatible method for rapid bacterial infection detection in 10 min. We use a large-volume solution scattering imaging (LVSi) system with low magnifications (1-2×) to visualize bacteria in clinical samples, thus eliminating the need for culture-based isolation and enrichment. We tracked multiple intrinsic phenotypic features of individual cells in a short video. By clustering these features with a simple machine learning algorithm, we can differentiate Escherichia coli from similar-sized polystyrene beads, distinguish bacteria with different shapes, and distinguish E. coli from urine particles. We applied the method to detect urinary tract infections in 104 patient urine samples with a 30 s LVSi video, and the results showed 92.3% accuracy compared with the clinical culture results. This technology provides opportunities for rapid bacterial infection diagnosis at POC settings.

Changes in the microbiome and associated host tissue structure in the blue mussel (Mytilus edulis) following exposure to polystyrene microparticles

Marine life is increasingly exposed to microplastics, which can be ingested and disrupt the relationship between host tissues and their microbiomes. We investigated the effects of microplastics (5 µm polystyrene beads) on the microbial community and host tissue structure in organs at high risk of exposure (digestive gland and gills) in blue mussels ( Mytilus edulis Linnaeus, 1758). We exposed mussels to concentrations of microplastic consistent with levels found in local coastal waters. High exposures (1000 particles per m3 per mussel) decreased the alpha and beta diversity in the microbiome of the digestive gland, with an increase in relative abundance of Polaribacter and a decrease in other species in the Flavobacteriaceae. Both low (10 particles per m3 per mussel) and high exposures to polystyrene also changed tissue structure in the hosts, with an increase in immune cells (hemocytes) and reactive lysosomes in the gills, and in the digestive gland, a loss of cell specialization in digestive cells and an increase in cell breakdown products. Thus, exposure to particles of polystyrene in concentrations consistent with levels detected in local coastal zones reduces microbial biodiversity of the digestive gland and disrupts host tissues, which may indicate a loss of the host–symbiont interactions that support tissue homeostasis.

Distinct Responses of Biofilm Carbon Metabolism to Nanoplastics with Different Surface Modifications.

Recently, there is an increasing concern regarding the toxicity of nanoplastics (NPs) on freshwater organisms. However, knowledge about the potential impacts of NPs with different surface modification on freshwater biofilms is still very limited. In this research, biofilms were cultured in lab and exposed to nano polystyrene (PS) beads: non-functionalized PS NPs, PS-COOH NPs, and the carbon source utilization of biofilms were measured by BIOLOG ECO microplates. The results showed that both two types of PS NPs significantly reduced the total carbon metabolic activity of biofilms, compared with the controls, whereas the carbon metabolic rate increased notably, especially for the PS-COOH NPs treatments at day 14. Moreover, results from six categories of carbon sources analysis suggested that PS NPs with different surface chemical properties exhibit distinct effects on the carbon utilization of biofilms, and the divergent changes of the specific carbon source category were observed at day 21 from the two PS NPs treatments. In addition, the metabolic functional diversity of biofilms were not altered by the PS NPs treatments. These findings highlighted that chemical properties of NPs play an important role in the toxic effects on the carbon metabolism activities of the biofilms. This study offers new insights that nanoplastics of different chemical characteristics have the ability to affect the microbial-mediated carbon cycling process in aquatic ecosystems.

Blood uptake and urine excretion of nano- and micro-plastics after a single exposure

Nano- and micro-plastic (NMP) pollution has emerged as a global issue; however, uptake in the blood is controversial. Also, there is no evidence that NMPs are excreted via urine. This study was designed to clarify the time course of NMPs absorption in blood and the excretion in urine.Male mice received a single administration of fluorescent polystyrene (PS) beads (100-nm and 3-μm) via tail vein injection, gavage, or pulmonary perfusion. Blood and urine samples were measured 0.5, 1, 2, and 4 h after exposure by confocal laser scanning microscope (CLSM). Transmission electron microscopy (TEM) was performed to corroborate the findings.Fluorescence particles were detected in both blood and urine from the 100-nm and 3-μm PS-treated groups after exposure. In the 3-μm PS treated group, particles with corresponding diameters were detected after intravenous injection and pulmonary perfusion, and particles with a diameter <3 μm were detected in blood samples after gavage. The fluorescent signal in urine was particularly weak and the size was <3 μm. Significant time course changes in fluorescence intensity were demonstrated in blood and urine (P < 0.05) after intravenous injection and pulmonary perfusion in the 100-nm PS-treated group. By contrast, significant changes were detected in the urine (P < 0.05), but not the blood, after gavage. TEM confirmed the presence of particles with corresponding diameters in blood samples; however, the excretion in urine was difficult to confirm for nano-plastics (NPs) and micro-plastics (MPs) because all particles with diameters of approximately 100 nm and 3 μm had irregular shapes and no clear boundaries.Our findings revealed that both NPs and MPs enter the blood circulation through digestive and respiratory pathways. Both 100-nm and 3-μm NMPs may be excreted through urine, but further evidence is needed. The physical and chemical properties of MPs may be impacted by digestive processes in vivo.

Assessment of Socket Pressure during Walking in Rapid Fit Prosthetic Sockets.

(1) Background: A sustainable casting system that combines the use of a polystyrene bag, a prosthetic liner and a vacuum system was developed to reduce fabrication time while maintaining comfort for the trans-tibial prosthesis user. (2) Methods: Eight prosthetists (28.7 ± 8.25 years old) fit ten trans-tibial prosthesis wearers (46 ± 12.4 years old) with two types of total surface bearing (TSB) prostheses; a polystyrene bead (PS) prosthesis and a plaster of paris (POP) prosthesis. Duration of casting and combined mean peak pressure was measured at six locations on the residual limb using Force Sensing Resistors (FSR). A pressure uniformity score (%) was determined. Socket Comfort Scale (SCS) was also measured. (3) Results: Duration of casting for the POP method was 64.8 ± 9.53 min and 7.8 ± 2 min for the PS method, (p = 0.006). Pressure uniformity in the POP prosthesis was 79.3 ± 6.54 and 81.7 ± 5.83 in the PS prosthesis (p = 0.027). SCS in both prosthesis types were equivalent. (4) Conclusion: A rapid fit PS prosthesis was developed, with significantly shorter duration than the traditional POP method. Socket pressure uniformity was confirmed and improved in the PS method. Socket comfort was equal between the two prothesis types.

Characterization Of Acoustofluidic Geometric Traps By Means Of Defocus Particle Tracking

In this work we used the General Defocusing Particle Tracking method to measure the three-dimensional trajectories of 10-μm-diameter polystyrene beads moving inside a micro-acoustofluidic device. The aim is to measure the change in acoustic energy density induced by localized modifications of the channel geometry. The measurements were performed in a glass capillary tube with a rectangular cross-section of 2.0 mm × 0.2 mm. The wall thickness of the capillary tube is 140 μm and it was locally increased by gluing a glass slide with a thickness of 100 μm. The acoustic energies at five different frequencies around the expected resonant frequency have been estimated for the single-glass and double-glass region from the measured particle paths. The results showed a down-shift of the resonant frequency in the double-glass zone, as expected from theoretical predictions. This approach can be used to create multiple acoustofluidic traps based on simple geometrical modifications of the microchannel.

Stable primary embryonic cells of Artemia are suitable for tracing the process of V. anguillarum and V. parahaemolyticus infection

The cell line is an important experimental tool to investigate the mechanism of host-pathogen interactions and to diagnose and cure diseases. However, their application in aquatic invertebrates is limited because they lack immortalized cell lines. The brine shrimp Artemia produces encysted diapause gastrula embryos under stress conditions. The biological advantages of Artemia embryos, such as quick switching on of the cell cycle upon short-term hydration and easy control of microbial contamination via decapsulation, makes them a candidate material for cell culture in vitro. This study identified five subpopulations of embryonic cells at the gastrula stage based on morphological characteristics. After 3–4 h of hydration, embryonic cells were derived from the cysts and successfully cultured for 10 days in 1.2 × L-15 medium containing 15% fetal bovine serum, with a cell viability of more than 90%. Using this primary cell culture system, Vibrio anguillarum and V. parahaemolyticus strains were screened as possible infectious Vibrio strains using laser confocal microscopy observations. The pathological features of viable Vibrio-challenged embryonic cells were further studied by comparing formaldehyde-inactivated and autoclaved Vibrio and polystyrene beads using SEM observation. The results confirmed that both Vibrio strains could challenge embryonic cells and cause some cytopathological features, such as cell aggregation and concaves. Our study provides the first evidence that in vitro cell culture of Artemia embryos can be used to demonstrate the characteristics of Vibrio infection. The primary cell culture system established in this study will facilitate research on the mechanism of host-pathogen interactions in aquatic animals.

(Invited, Digital Presentation) Influence of Hemisphere-Shaped Nanodimples of Gold Electrode on Capacitance in Ionic Liquid

Ionic liquids (ILs) have attracted much attention as promising electrolytes for electrochemical devices due to their wide electrochemical window (stability) and negligible vaporization. For such applications, nanostructured electrodes have advantage on their large surface area leading to accumulation of large density energy at the interface. However, recent reports on IL/electrode interfaces revealed that quite unique structures can be formed, and it is not clear how the interface forms and how it changes by forming an electric double layer (EDL). In this study, we investigated the interfacial capacitance of nanostructured Au electrodes using electrochemical impedance spectroscopy (EIS) and IR measurements.Polystyrene beads were self-assembled in a close packed form on a gold substrate by dipping in polystyrene beads solution and rapid drying. Au electrodeposition on thus prepared surface followed by removal of the beads resulted in the fabrication of a nanostructured Au electrode with periodic dimples. Electrochemical behavior of a ferrocene dissolved ionic liquid (1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl) amide (BMI-TFSA)) at the nanostructured and flat Au electrodes were investigated by EIS. We found that the capacitance of the nanostructured electrode was smaller than that of the flat electrode in the whole potential range. This result suggests that the thickness of the electric double layer formed in the nano-sized dimple is thicker than that formed on the flat surface. In the case of nanostructured Au electrode having 160 nm diameter dimples, the large capacitance was observed comparing with other electrodes having the dimples of different sizes. In addition, on the negative-going scan, the capacitance takes maximum at 0.1 V vs. Fc/Fc+, whereas no peak was found on the reverse positive-going scan. This result indicates that the exchange of cation/anion layers smoothly proceeded on the negative-going scan, whereas such a smooth exchange was prevented due to strongly surface-adsorbed BMIM+ on the positive-going scan. We also found that the hysteresis behavior was relatively suppressed in the case of the electrodes having 70 nm and 120 nm diameter dimples. We carried out the In-situ ATR-IR measurement to investigate the structure of ionic liquid molecules at the ionic liquid/electrode interface. The details of the relationships between the arrangement of ionic liquid at the interface and the capacitance of the electrode will be discussed.

An imaging flow cytometry-based methodology for the analysis of single extracellular vesicles in unprocessed human plasma

Extracellular vesicles (EVs) are tissue-specific particles released by cells containing valuable diagnostic information in the form of various biomolecules. To rule out selection bias or introduction of artefacts caused by EV isolation techniques, we present a clinically feasible, imaging flow cytometry (IFCM)–based methodology to phenotype and determine the concentration of EVs with a diameter ≤400 nm in human platelet-poor plasma (PPP) without prior isolation of EVs. Instrument calibration (both size and fluorescence) were performed with commercial polystyrene beads. Detergent treatment of EVs was performed to discriminate true vesicular events from artefacts. Using a combination of markers (CFSE & Tetraspanins, or CD9 & CD31) we found that >90% of double-positive fluorescent events represented single EVs. Through this work, we provide a framework that will allow the application of IFCM for EV analysis in peripheral blood plasma in a plethora of experimental and potentially diagnostic settings. Additionally, this direct approach for EV analysis will enable researchers to explore corners of EVs as cellular messengers in healthy and pathological conditions.

Imaging Flow Cytometry for Sizing and Counting of Subvisible Particles in Biotherapeutics

Imaging flow cytometry (IFC), a technique originally designed for cellular imaging, is featured by the parallel acquisition in brightfield (BF), fluorescence (FL), and side scattering channels. Introduced to the field of subvisible particle analysis in biopharmaceuticals roughly ten years ago, it has the potential to yield additional information, e.g., on particle origin. Here, we present an extensive, systematic development of masks for IFC image analysis to optimize the accuracy of size determination of polystyrene beads and pharmaceutically relevant particles (protein, silicone oil) in BF and FL channels. Based on the developed masks, particle sizing and counting by IFC are compared to flow imaging microscopy (FIM). Mask verification based on fluorescent polystyrene particles revealed good agreement between sizes obtained from IFC and FIM. In the evaluation of counting accuracy, IFC reported lower concentrations for polystyrene particle standards than FIM. For the analysis of fluorescently stained silicone oil and protein particles however, IFC FL imaging reported higher particle concentrations in the low micrometer size range. Overall, we identified IFC as suitable tool to generate supportive data for particle characterization purposes or trouble shooting activities, but not as routine quantitative technique, e.g., for subvisible particle analysis during drug product development or quality control.

The effect of expanded polystyrene beads (EPS) on the physical and mechanical properties of aerated concrete

Abstract There is a significant challenge to developing the strength and durability of the aerated concrete (AC) for structural applications, but to date, no researchers have focussed on the effect of expanded polystyrene beads (EPS) on the AC properties. EPS-AC consists of cement, sand, water and aluminium powder with commercially available spherical small, hollow and impermeable polystyrene beads. In this research, different contents of EPS from 0 to 4% by cement weight were added to create the AC with different densities. It is revealed that the greatest enhancements in the properties of EPS-AC were noticed when the EPS volume fraction was increased to 4%. The compressive, flexural strength and modulus of rupture were enhanced by 48, 37 and 125% respectively, whereas the density was raised slightly. Moreover, it was shown that all EPS-AC mixes could satisfy the requirements of structural lightweight concrete.

Biobarcode and sequence-responsive DNA nanocapsules for label-free and sensitive electrochemical detection of circulating tumor cells

Monitoring trace circulating tumor cells (CTCs) in whole blood is important for early diagnosis and treatment of cancers. Whereas, it remains a major difficulty for detecting CTCs because of their extremely low contents in blood. Herein, by coupling biobarcode amplification method with sequence-responsive and enzyme-embedded DNA nanocapsules, we report a highly sensitive, label-free and specific electrochemical sensing assay to detect CTCs in blood. The target CTCs are selectively isolated from sample solutions by aptamer-conjugated magnetic beads and biobarcode DNA-functionalized polystyrene beads. Subsequent release of the biobarcode DNA can trigger the liberation of lots of enzymes from the nanocapsules, further leading to drastically enhanced catalytic current on the sensor electrode for detecting CTCs at the detection limit of 8 cell mL−1 in a non-label approach. Moreover, whole blood-spiked target CTCs can also be detected by the developed strategy, offering it the great promise for the monitoring of different rare CTCs in complex samples for various biomedical applications.

Charge Transfer in Patterned Bilayer Film of Ag/ZnS Composite by Magnetron Control Sputtering.

Ordered heterojunction nanocap arrays composed of the bilayer film Ag/ZnS were prepared onto ordered two-dimensional polystyrene bead arrays by magnetron control sputtering, and the surface morphologies were tuned by changing the ZnS thickness. When the ZnS thickness varied from 10 to 30 nm with a Ag thickness of 5 nm, the roughness of the bilayer film Ag/ZnS increased obviously. The UV–VIS spectra showed the shifted LSPR peaks with ZnS thickness, which was attributed to the changes of the electron density as confirmed by Hall effect analysis. SERS observations confirmed the charge transfer process for the varied electromagnetic couplings when the ZnS thickness changed.

AFM microfluidic cantilevers as weight sensors for live single cell mass measurements

Reliably measuring small mass changes at the single-cell level is challenging. In this manuscript, we report the use of microfluidic cantilevers in liquid with sub-nanogram scale weight sensing capability for the measurement of cellular mass changes of living single cells. With this instrumentation, we were able to perform fast mass measurements within 3 min. We show results of mass measurements of polystyrene and metal beads of various sizes (smallest weight measured at 280 ± 95 pg) and live single-cell mass measurements in a physiologically relevant environment. We also performed finite element analysis to simulate and optimize the structural design and materials of cantilevers. Our simulation results indicate that using polymer materials, such as SU8 and polyimide, could improve the minimal detectable mass by three-fold compared to conventional silicon cantilevers. The simulations also suggest that smaller dimensions of length, width, and thickness would improve the mass detection capability of microfluidic cantilevers.