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A novel naphthalimide-based solid-phase fluorescence pH sensor (PS-Acyl-II) is prepared by immobilization of a small molecule probe (II) on polystyrene microspheres through an ester bond and is characterized by Fourier-transform infrared spectroscopy, optical microscope, scanning electron microscope, and conductiometric titrations. The sensor can determine the pH of a solution within the pH 4.0–7.0, free from interference of common metal ions, and can be reused several times. The geometries of II, PS-Acyl-II, and its product with H+ are optimized at the B3LYP/6-31G** level by density functional theory. The charge distribution, orbital interactions, and bonding characteristics are analyzed and compared in detail to discuss the recognition mechanism and structure–fluorescence property relationships.

With the increasing difficulty in exploitation of low-permeability, high water content and other unconventional reservoirs, a new kind of proppants that possess not only ultra-light weight and high strength and but also hydrophobic performances have attracted more and more interests. Here, this kind of proppants were designed and prepared successfully in the form of polymer microspheres. What's more is that the polymer microspheres (named O-MSDBs) showing high strength and stable hydrophobicity were prepared by a one-step suspension polymerization between styrene, divinyl benzene and γ-methacryloxypropyl-trimethoxy silane accompanying with the formation of silica through sol–gel process. When compared with reported ultra-lightweight proppants (ULWPs), the O-MSDBs not only perform better in ultra-lightweight (0.9917 g·cm−3) and are comparable in high strength (low crushing ratio of 0.89–2.53% at 55–69 MPa), but also show new hydrophobic function. The water contact angle on the surface of O-MSDBs is 140.7° that keeps about more than 80% after mechanical abrasion or acid dissolution. The one-step facile preparation method and brilliant performances make O-MSDBs very promising to large-scale preparation and widely applied in fracturing technology as proppants.

—At present, quite a large number of inducers forming neutrophilic extracellular traps (NET) have been described. Mechanical factors (MF) are of particular importance, since they are constantly acting as neutrophils pass through the microcirculatory system. An adequate choice of therapy for various diseases accompanied by excessive NET formation requires assessment of the ability of a patient’s neutrophils to form NET in response to various inducers. Studying the role of MF in neutrophil activation in patients presents certain difficulties associated with introducing expensive and complex recording systems into laboratory practice. A possible alternative to the existing approaches can be joint incubation of whole blood with hemocompatible polymer microspheres (PMS). To develop this approach, polystyrene microspheres containing quaternary ammonium groups were obtained, on the surface of which hemocompatible aggregates consisting of thiooctadecyl poly-N-vinyl-2-pyrrolidone (PMSnano) were attached. The data obtained indicate that with incubation of blood samples with PMSnano under gentle stirring, the amount of formed NET is statistically significantly higher than in a stationary incubation mode. This confirms the idea that MF are capable of activating neutrophils and triggering the NET formation process. The proposed approach to assessing the effect of MF on neutrophil activation processes owing to its ease of implementation may find wide application both in biomedical research and clinical laboratories.

A new class of lithium-ion conducting Solid Polymer Electrolytes (SPEs) has been derived from oligomeric Polyethylene Oxide (PEO)-grafted Cross-linked Polystyrene (XPS) microspheres containing one or two lithium sulfonamide moieties. The SPE containing Li:O mole ratio of 1:8 displayed excellent ionic conductivity (in excess of 10-4S/cm at 25ºC) and good electrochemical stability (4.3 volts versus Li/Li+). Thermal properties of these SPEs have also been investigated with Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). These new SPEs possess amorphous character with a glass Transition Temperature (Tg) around 135ºC, and no significant thermal decomposition until 420ºC. Synthesis and characterization including surface morphologies of these SPEs are described.

Surface physicochemistry properties of polymer particles are crucial for protein corona formation and macrophage phagocytosis when they contact with living body. In this work, polystyrene microspheres (PS-MSs) were selected as a model of polymer microparticles and fabricated by chromic acid etching through controlling conditions to obtain different surface morphology structures and to investigate their effect on the protein adsorption and phagocytic uptake of PS-MSs. The adsorption of bovine serum albumin (BSA) and fibrinogen (FIB) on PS-MSs showed almost the same tendency, i.e. the etched PS-MSs presented lower protein adsorption compared with original microspheres. The adsorption of BSA and FIB was the lowest when the protuberances on the etched surfaces were maximum and the size of the protuberances was minimum. Furthermore, the surface morphologies of PS-MSs were influenced in return not only by the amounts of proteins but also by protein types. Meanwhile, the macrophages phagocytosis of PS-MSs depended on the amounts and kinds of adsorbed proteins, especially the albumin content. In a word, phagocytosis and protein adsorption can be regulated by microsphere morphologies through etching, which provides a promising strategy to avoid invalid uptake for polymer particles such as drug delivery carriers.

In order to develop the in-vitro diagnostic chips with dry chemical methods that have good diffusion performance, high accuracy of test results, and good reproducibility, the synthesis conditions o...

Electrostatic self-potentials of individual particles trapped at an oil–water interface were determined, and the effects of surface chemical nonuniformity on heterogeneous self-potentials and equilibrium microstructures were investigated. Direct measurement of the pair interactions and the self-potentials of polystyrene microspheres were performed using optical laser tweezers. The individual particles had different self-potentials even when they possessed the same surface functionalities. Atomic force microscopy measurements elucidated the relationship between nonuniform surface charge distribution and heterogeneity and magnitude of self-potentials. Monte Carlo simulations demonstrated that self-potential heterogeneity led to the formation of more melted microstructures that showed excellent consistency with experiments.

A tiny object active releasing method is proposed in this paper. Each jaw of the microgripper is driven by a piezoceramic actuator (PEA), which can be controlled independently. Shear force generated by the longitudinal motion of right jaw is utilized to overcome the adhesion force between the object and the jaw during releasing step. Based on Johnson-Kendall-Roberts (JKR) theory, analysis model is established to understand the release mechanism. Copper wire and polystyrene microspheres with different diameters are adopted to carry out the experiments to investigate the performance of the release strategy. The experimental results show that the objects can be released successfully, and this releasing method isn't limited by the materials of the objects.

Molecular imprinted polymer microspheres (MIP) were prepared by a one-step swelling polymerization method using polystyrene microspheres as seeds, congo red (CR) as template molecules, methacrylic ...

The addition of biochar to sand columns can enhance the retention of bacteria and thus may provide a management strategy for removing bacteria from tile-drainage waters. In this study, the role of sand size as a factor in controlling microbial retention in biochar-amended sand columns was investigated. Laboratory column experiments were conducted to quantify the removal of two bacterial isolates (E. coli and Salmonella) and polystyrene microspheres in 10-cm-long columns packed with clean sand of three different sizes (0.25, 0.71, and 1.19 mm) at four biochar concentrations (0%, 5%, 10%, and 15%). Sorption studies were also performed to help identify the relative roles of sorption and physical straining on the removal of bacteria and microspheres within the columns. For the large sand, the log10 removal values (LRV) for E. coli increased from 0.22 to 0.49 for the 0% and 15% biochar concentrations, respectively, while LRV for Salmonella increased from 0.19 to 0.68. For the small sand, increasing biochar concentration from 0% to 15% increased LRV from 0.11 to 1.9 for E. coli and from 0.20 to 4.6 for Salmonella. In comparison, LRV for microspheres in the 15% biochar columns was only minimally higher than the unamended columns for all three sand sizes. Results from the sorption studies show that high sorption coefficients generally correlated with high LRV indicating that sorption rather than physical straining was the primary mechanism of retention in the columns. Results from this study further our understanding of bacterial retention in biochar-amended porous media.

Chloromethylated cross-linked polystyrene (CMCPS) microsphere is hydroxylated, obtaining hydroxylated cross-linked polystyrene microsphere (CPS-OH). Methacrylic acid (MAA) is grafted on the surface...

The structures of individual polystyrene microspheres obtained in the presence of organosilicon surfactants were studied by transmission electron microscopy. The density of the macro-molecule distribution over the cross section of particles was determined. The synthesized latex particles have a core—shell structure.

Objective: To describe the outcomes of a new product based on negatively charged polystyrene microspheres (NCM) technology, in non-responding diabetic foot ulcers (DFU). Methods: A clinical case series of patients with a hard-to-heal DFU treated with NCM were recruited between March and June 2017 in a specialised diabetic foot unit. DFUs were treated daily with NCM over four weeks, although the health professional could decide to continue NCM treatment in some patients. Cases were followed up for 12 weeks. Wollina score (granulation, colour and consistency tissue), wound area (cm2), percentage reduction and wound closure (%) were measured. Results: A total of 22 ulcers (19 patients) were included, of which three patients (five ulcers) were withdrawn due to adverse events: four infections and one necrosis. None were associated with the product. NCM treatment was completed in 17 ulcers (16 patients). The mean patient age was 61.53±9.57 years. At baseline, mean duration time of the DFU was 7.88±8.65 weeks, the median area was 5.35cm2, the interquartile range (IQR) was 1.45 to 4.65cm2 and positive probe-to-bone test (PTB+) was recorded at 29.4%. After four weeks of treatment, an increase in Wollina score (3.65±2.12 to 5.69±1.18; p=0.000), a 62.2% reduction of the ulcer area (5.35 cm2; IQR: 1.45 to 4.65cm2) to 3.33cm2 (IQR: 0.25 to 1.70cm2; pConclusion: After NCM use, a reactivation of the healing process in non-responding wounds was observed, having a significant improvement in Wollina score as well as reduction of the wounds. Complete healing was achieved in all ulcers at 12 weeks, including PTB+.

Polarized light scattering spectroscopy (PLSS) is a promising optical technique developed for the detection of cancer, which extracts the single scattering light to infer morphological information of epithelial cells. However, traditional PLSS uses either a rotatable polarizer or two orthogonal polarizers to purify the single scattering light, which makes it complicated and challenged to build a PLSS endoscope. Herein, we propose a snapshot PLSS with a single optical path to directly get the single scattering light for the first time. The single scattering light is encoded using the spectrally-modulated polarimetry and decoded using the continuous slide iterative method. Both the polystyrene microsphere solutions and the ex vivo gastric cancer samples are used to verify the method. The experimental results of the snapshot PLSS are consistent well with that of the traditional PLSS. The proposed method has a potential for the building of snapshot PLSS endoscope systems in future.

Droplet microfluidics offers exquisite control over the flows of multiple fluids in micro-scale, enabling fabrication of advanced microspheres with precisely tuneable structures. The main goal of this work was to design monodispersed carboxylated polystyrene microspheres with a developed pore structure (a specific surface area more than 200 m

Background After physiological recordings are performed in behaving animals, it is valuable to identify microelectrode tracks in histological sections so that neuronal responses can be correlated with brain anatomy. However, no good method currently exists for long-term labeling, so that microelectrode tracks can be recovered months or even years after recording sessions. New Method Penetrations were made into the brains of mice with microelectrodes coated with fluorescent dyes packaged into 0.2 μm polystyrene microspheres, followed by survival periods of 3 days, 2, 4, or 6 months. Sections were examined by fluorescence microscopy before and after cytochrome oxidase histochemistry to identify microelectrode tracks. Results After all 4 survival periods, 0.2 μm fluorescent microspheres clearly marked the tracks of microelectrode penetrations. Comparison with Existing Methods Fluorescent microspheres label microelectrode penetrations for longer than do fluorescent lipophilic dyes, such as FM 1−43FX. The label appears punctate, and resistant to degradation, because it is protected by the barrier of the polystyrene micro-container. Conclusions Coating of microelectrodes with fluorescent microspheres allows one to identify the penetration track in histological sections half a year later. This technique may be useful when electrophysiological recording sessions are being carried out in behaving animals, with plans to identify electrode tracks in histological sections many months later.

As an important kind of environmental endocrine disruptors, 17 β -Estradiol (E2) plays a major role in affecting the growth of human including sexual characters, pregnancy system, etc. In the modern society, with the threat of abuse in breeding, it is imperative to design sensitive methods for detecting low concentration of E2 in environment. In this work, we constructed a highly sensitive and simple fluorescent aptasenor for detecting E2 via amplification of hybridization chain reaction (HCR) and horseradish peroxidase (HRP). Through the competitions between complementary strand (cmDNA) and E2 to E2 aptamer modified on magnetic beads, the unbound cmDNA would be collected and captured by polystyrene microspheres to induce HCR which brought abundant biotin sites. Subsequently, benefit from the excellent catalytic performance of streptavidin-horseradish peroxidase (SA-HRP), the highly sensitive fluorescence signals could be obtained in low concentration of E2. Under the optimal conditions, the prospered method for E2 detection was shown a good liner range from 1 to 100 pg/mL, with the lower detecting limit of 0.2 pg/mL compared with previous work. In addition, the recovery rates tested in the real samples of milk and water were 99.20%–108.06% and 91.07%–106.13%. In all, the assay may provide a perspective way for highly sensitive detection for various contaminants in the real samples.

—The significance of the Yersinia pseudotuberculosis porins OmpF and OmpC for adhesion to macrophages J774 was assessed using optical trapping. The passive sensitization of polystyrene microspheres with the preparations of these porins was verified. Using a set of differently functionalized microspheres, it was shown that OmpF produced at a lower culture temperature contributes to the adhesiveness of the bacteria Y. pseudotuberculosis to macrophages, while OmpC synthesized at a temperature of 37°C does not have this property. These results can be explained by thermoinducible differences in the primary structure and conformational features of the outer loops of porin molecules. These differences are suggested to be necessary for effective circulation in the environment and manifestation of the invasive properties of Y. pseudotuberculosis as an agent of saprozoonotic infection.

To take advantage of the polymer’s special properties, we synthesized PVDAT coated polystyrene (PVDAT@PS) microspheres through semi-continuous precipitation polymerization, and demonstrated the possibility of controlling the size of microspheres by using different sized PS cores. Mechanism of the microsphere synthesis was investigated. Preliminary application studies indicated that the synthesized microspheres adsorbed double-stranded DNAs (dsDNAs) comprising A-T base pairs in pH7.4 phosphate buffered saline, and the adsorption capacity was in a range of 3.28mg to 5.58mg per gram PVDAT@ PS microspheres depending on A-T base pair percentage and chain length of the dsDNAs.

Uniform polystyrene (PS) microspheres are synthesized by dispersion polymerization in a continuous long tubular reactor (CLTR) system, whereas the batch reactor system yields ∼1.8 fold smaller PS microspheres because the CLTR system has higher conversion (∼92%) and more number of nuclei at early stage than the batch system (∼68 %) due to better heat transfer. The uniform PS microspheres can be synthesized in CLTR system with high conversion if the residence time (reaction time) in CLTR is longer than the saturation time of reaction (conversion). In addition, when we apply the PS microspheres to antiglare (AG) film for high resolution displays, the AG film exhibits good pencil hardness of 4 H under 200 g load and internal, external, and total haze of 12.50, 4.38, and 16.88, respectively.

We report the surface modification of polystyrene microsphere by ozone treatment. The effects of the ozone treatment on the surface properties of polystyrene microsphere are probed using a series o...

A novel piezoresistive pressure sensor based on silver-coated polystyrene (Ag@PS) microspheres filled in a poly-dimethylsiloxane (PDMS) substrate with a cavity was successfully manufactured. This s...

Thrombosis or embolism is the leading cause of death and long-term adult disability worldwide. To reduce the risk of thrombosis and hemorrhaging in patients, a facile and versatile method was developed to fabricate microcapsules for targeted antithrombotic drug delivery. The microcapsules were prepared via oxidative polymerization of dopamine on polystyrene microspheres, followed by immobilization of fibrinogen onto the surface of poly(dopamine) layers. Subsequently, microcapsules were obtained by removing the cores with THF. Nattokinase was loaded into the microcapsules via diffusion. The loading amount was approximately 0.05 mg g−1 at 37 °C, and the loading efficiency was nearly 75%, based on the initial concentration of nattokinase in PBS. The release of nattokinase was a gradual process at 37 °C, and the activity of the targeted activated platelets was highly efficient. The antithrombotic activity of the nattokinase microcapsules was evidenced by the sharp dissolution of fibrin clots and the blood clotting time indexes. A gradual release mechanism of platelet-inspired microcapsules used for targeted antithrombotic therapy was proposed. This strategy for targeted antithrombotic drug delivery, which lowers the demand dose and minimizes side effects while maximizing drug efficacy, provides a potential new way to treat life-threatening diseases caused by vascular disruption.

We report on a novel, to the best of our knowledge, optical scheme of an annular optical trap based on an acousto-optic tunable spatial filter. Design of the optical trap is proposed and validated. Experimental demonstration with polystyrene microspheres includes controllable arrangement of freely floating particles into a circular pattern, aggregation, and disaggregation of the particles. Dynamical adjustment of the trapping field potential diameter is achieved by programmable frequency-swept controlling of the acousto-optic filter.

A microfluidic colorimetric biosensor was developed using thiolated polystyrene microspheres (SH-PSs) for aggregating of gold nanoparticles (AuNPs), a novel hose-based microvalve for controlling the flow direction, and a smartphone imaging APP for monitoring colorimetric signals. Aptamer-PS-cysteamine conjugates were used as detection probes and reacted with Salmonella in samples. Complementary DNA - magnetic nanoparticle (cDNA - MNP) conjugates were used as capture probes, reacted with the free aptamer-PS-cysteamine conjugates. AuNPs were aggregated on the surface of Salmonella-aptamer-PS-cysteamine conjugates, resulting in a visible color change in the detection chamber, which indicating different concentrations of Salmonella. The limit of detection was low to 6.0 × 101 cfu/mL. The microfluidic biosensor exhibited a good specificity. It was evaluated by analyzing salad samples spiked with Salmonella. The recoveries ranged from 91.68% to 113.76%, which indicated its potential application in real samples.

Organic phototransistors (OPTs) have been intensively studied in recent years due to the combined advantages of phototransistors and organic semiconductors (OSCs). However, the electrical performance of OPTs is largely limited by OSCs themselves, posing a challenge to further improve the performance of the devices. Preparing nano/micro-structures of OSCs is considered as an effective way to improve the performance of OPTs. Polystyrene (PS) microsphere, as a kind of insulating and low-cost material, is extensively used in fabricating nano/microporous structures, and the resulting devices exhibit high response to external stimuli. Therefore, we combined PS microspheres with OSCs to fabricate PS/OSC OPTs, and the Ilight/Idark ratio was enhanced by two orders of magnitude compared with the pristine counterparts, which can be modulated from 46 to 1800 by controlling the diameters of PS microspheres. This strategy paves a way for developing high-performance OPTs with nano/microporous structures with potential applications in organic optoelectronics.

Rationally designed synthesis strategy for well-defined morphology which can endow the catalysts with unexpectedly enhanced catalytic properties remains a significant challenge in heterogeneous cat...

Heterophase polymerisation of styrene was carried out, and nanocomposite polystyrene microspheres with a controllable content of ZnO nanoparticles were synthesised. The colloid chemical properties of the obtained polymer suspensions were studied, and it was shown that the particles have a ‘core–shell’ structure with a ZnO content of up to 30%.

A novel microsphere-based fluorescent sensor 1 for determination of Hg(II) in food samples has been successfully synthesized and its fluorescent sensing properties were investigated in detail. Poly...

Hypercrosslinked polystyrene (HCLPS) microspheres with ultrahigh surface area have been prepared via dispersion polymerization and post cross-linking. The microspheres were predominantly microporous and exhibited surface area of 1161 m2/g, and the total pore volume of 0.72 cm3/g. HCLPS microspheres could be enough swollen in organic solvent and water in spite of thermodynamic compatibility. Furthermore, gas storage capacity of HCLPS microspheres was also investigated, and the results indicated that the microspheres could reversibly store up to 2.27 wt% H2 at 1bar/77.3 K, and 14.8 wt% CO2 at 1bar/273 K. Therefore, as-prepared HCLPS microspheres were promising materials for use in packing materials of HPLC, adsorbents for organic compound, and gas storage materials.

A kind of manipulative oil in water Pickering emulsion stabilized by heterogeneously modified cellulose nanocrystals (CNCs) and its application as a template for the creation of functional polystyrene microspheres were presented in this study. First, 18-carbon alkyl long chains were selectively introduced at the reducing ends of CNCs through a two-step chemical process including the hydrazone reaction and the amidation reaction. The as-obtained heterogeneously modified CNCs (CNC–C18) were then used as emulsifiers for the formation of oil in water Pickering emulsions. Compared with the pristine CNCs used in this study, CNC–C18 exhibited a high emulsifying performance. Highly stable oil in water Pickering emulsions could be formed at a low content of CNC–C18 nanoparticles. Because of the pH-responsive stability of the C═N bond linkages between 18-carbon alkyl chains and CNCs, the introduced 18-carbon alkyl chains could be cleaved completely at a suitable acid condition, and this endowed the formed Pickering...

Colloidal gold and Eu3+ -doped fluorescent microspheres were applied as labels to develop the immunochromatographic strips for detecting melamine in milk. Under the optimized condition, the visual detection limit of colloidal gold-immunochromatographic test strip (ICTS) was 150 μg/L of melamine in phosphate-buffered saline (PBS), although the visual detection limit of fluorescent nanoparticles (FN)-ICTS was 75 μg/L in PBS. As thermal acceleration test, FN-ICTS could be stored at 37 °C for at least 11 d before sample testing, but the color of the lines on colloidal gold-ICTS faded away after 7-d storage. The visual result of FN-ICTS was more stable than that of colloidal gold-ICTS, and the fluorescence intensity of the line on FN-ICTS could be maintained up to 30 d at 22 °C after sample testing. Once the immunochromatographic strips were used to detect melamine in milk, no negative effect of milk components on the performance of FN-ICTS was identified, whereas the performance of colloidal gold-ICTS was significantly influenced by milk matrix.

Flexible pressure sensors are currently at the center stage of wearable electronics. Despite tremendous progress in the recent years, flexible pressure sensors with high sensitivity, high stability, and mechanical robustness are still challenging. In this paper, as inspired by the bean pod structure, a sensor architecture consisting a microspacer core layer of polystyrene (PS) microspheres, sandwiched between two laser-induced graphene/polyurethane (LIG/PU) films, is presented. A flexible and self-healable pressure sensor is prepared, achieving ultrahigh sensitivity, improved linearity, wide sensing range up to 100 kPa, and excellent stability (for over 1000 loading-unloading cycles). Specifically, the pressure sensor achieves high sensitivities of 149, 659, and 2048 kPa

Objectives: The aim of this study was to test the Bioimpedance probe needle on in-vitro tissue phantom. Study Design: Bioimpedance probe needle that was connected to a bioimpedance measurement device to record spectra in the kHz range. The probe consists of an 18Gauge 1.2x89 mm spinal needle. The probe was used for obtaining impedance information about the polystyrene microspheres which were in different diameters; 1, 2 and 4 micrometers. The current was transferred to the phantom and conductivity information was obtained by the probe. Results: Bioimpedance probe needle allows the discrimination of different particle sizes based on their specific signatures. The sensitivity of the probe to particle size in tissue phantom was tested during the study. Spectroscopic data were evaluated with resistance values at 50 kHz and the information about the particle size in the tissue phantom was obtained. Bioimpedance spectra results which were obtained from polystyrene microspheres showed that the resistance values were increasing while the size of the particle was enlarging. Conclusion: Due to the highly accurate differentiation of particle size in the tissue phantom, our probe has the potential to be used in the rapid detection of Escherichia coli or Acinetobacter baumannii which have different sized microorganisms in the tapped cerebrospinal fluid without being cultured in real time. In addition, it is possible for the probe to perform cell counting and differentiation in cell culture studies.

This paper presents a novel way of ejecting particles (Polystyrene microspheres) carried by liquid droplets through and from agarose-gel-filled Petri dish with high-intensity focused-ultrasound generated from self-focusing acoustic transducers working on the 3rd, 5th and 9th harmonic resonant frequencies of 1-mm-thick lead zirconate titanate (PZT) sheets. With different designs, the ejection spot area (related to focal size) is varied, so that the number of particles per ejection may be precisely controlled.

Samples of liquid dispersions of 4 μm polystyrene microspheres with cyanine 5 and cyanine 5.5 dyes were synthesized and studied using developed experimental setup for fluorescence microscopy. It was shown the possibility of identification of microspheres with different dyes and different dye concentration in the image. The low coefficient of variation of fluorescence intensity in the image makes it possible to use a large number of types of spectrally encoded microspheres in the immunofluorescence analysis.

Visible particles may potentially pose safety and efficacy concerns if inadvertently administered to patients; therefore, it is crucial to monitor and characterize these particles. These particles may be composed of proteinaceous or non-proteinaceous material. Although particles made of non-proteinaceous material are unacceptable in drug products, proteinaceous particles may be acceptable on a case-by-case basis if they are characterized and shown to not pose any quality, efficacy, or safety concerns. The focus of this manuscript is on the proteinaceous particles that may potentially form in some biopharmaceuticals. Monitoring and tracking proteinaceous particles in these biopharmaceuticals can be challenging, but a universal protein-like particle standard might be able to help. The aim of this work is to evaluate abraded ethylene tetrafluoroethylene (ETFE) as a visible protein-like particle standard and demonstrate a semiquantitative method to show how this surrogate can be used to effectively monitor proteinaceous particles during formulation and analytical development. Studies indicated that the ETFE particles in solution better mimic the appearance and behavior of protein particles than the commonly used polystyrene microsphere standards and therefore could be a viable standard for visible proteinaceous particles. Such standards and the semiquantitative method illustrated could be used effectively during development to nondestructively identify potential stability problems. LAY ABSTRACT: Routine visual inspection of protein biopharmaceuticals is crucial to ensure the quality and consistency of drug products. Visible particles may potentially pose safety and efficacy concerns if administered to patients; therefore, it is important to monitor and to minimize them as much as possible. Visible proteinaceous particles, composed of aggregated protein in biopharmaceuticals, may be acceptable on a case-by-case basis if they are characterized and shown not to pose any quality, efficacy, or safety concerns. Monitoring and tracking these visible proteinaceous particles are challenging and could be aided by the use of a universal protein-like particle standard. In this work, a new visible protein-like particle surrogate made of ethylene tetrafluoroethylene (ETFE) will be introduced, and its use will be explored by developing a semiquantitative method to monitor proteinaceous particles in protein products. These studies show that ETFE particles possess desirable traits to become a viable protein-like particle standard that could be used during formulation development and to nondestructively identify potential stability problems.

This work for the first time demonstrates a single-cell impedance micro-cytometer with 3D differential electrodes and fluidic sidewalls completely made of silver-PDMS composites (AgPDMS). Such monolithically integrated electro-fluidic structure is an outcome of one-step molding from a readily used master, obviating extra sacrificial layer patterning as required in the existing device incorporating AgPDMS electrodes. To maintain maximum sensitivity, the device exploits 3D sidewall electrode configured differentially with minimized sensing volume between the electrodes. The micro-cytometer has been showcased here for flow impedance measurement of polystyrene microspheres at multiple frequencies, as well as real-time differentiation between 7 μm beads and human red blood cells (RBCs) featuring similar size.

Polymer microparticles with complex microstructures, including cut spheres, bowl-like particles, hollow spheres with holes and porous hollow spheres, were prepared via phase separation in polymer microspheres. The incorporation of sulfonic acid groups is crucial, and the resulting microparticles are in sharp contrast to those prepared from regular polystyrene microspheres.