Polystyrene Latex Beads Research Articles

Prediction models for the flux decay profile and initial flux of microfiltration for therapeutic proteins.

Microfiltration (MF) is an essential step during biopharmaceutical manufacturing. However, unexpected flux decay can occur. Although the flux decay profile and initial flux are important factors determining MF filterability, predicting them accurately is challenging, as the root cause of unexpected flux decay remains elusive. In this study, the methodology for developing a prediction model of flux decay profiles was established. First, the filtration profiles of different monodisperse polystyrene latex and silica beads of various sizes were evaluated. These results revealed that the size and surface electrostatic properties of the beads affect the flux decay profile. Taking the size and surface electrostatic properties of protein aggregates into account, we constructed a predictive model using model bead filtration profiles. We showed that this methodology was applicable to two different MF filters to predict the flux decay profile of therapeutic proteins. Because our proposed prediction model is based on normalized flux, the initial flux is required to predict the overall filtration profile. Then, we applied the Hagen-Poiseuille equation using sample viscosity values to estimate the initial flux. The developed prediction models can be used for effective MF scale-up assessment during the early stages of process development.

A novel reagent for the screening of haptoglobin-deficient blood donors.

In Japan, the prevalence of haptoglobin deficiency is approximately 1 in 4000. Haptoglobin-deficient individuals may produce anti-haptoglobin from allo-immunization, leading to serious transfusion reactions. Therefore, implementation of a consistent supply of haptoglobin-deficient fresh frozen plasma is crucial. We developed a novel reagent to facilitate large-scale identification of haptoglobin-deficient individuals as potential donors of plasma products. We established mouse monoclonal anti-haptoglobin-producing cell lines (three clones) using the hybridoma method by immunizing mice with the haptoglobin protein. Purified antibodies were conjugated with carboxylate-modified polystyrene latex beads and used for haptoglobin measurements by the latex agglutination method using an automatic analyser (LABOSPECT008). Samples with low protein concentrations were re-examined by enzyme-linked immunosorbent assay to confirm the results. Additionally, the haptoglobin gene was amplified by polymerase chain reaction to confirm the haptoglobin deletion allele (Hpdel ). From February to October 2022, 7476 blood donor samples were screened. Two haptoglobin-deficient and 21 low-haptoglobin-expressing individuals were identified. Two haptoglobin-deficient donors were found homozygous for Hpdel , and 19 (90%) of the 21 low-haptoglobin-expressing individuals were heterozygous for Hpdel , which includes the first reported case of heterozygous Hpdel /HpJohnson . We developed a new reagent for the detection of haptoglobin deficiency, which is automatable and inexpensive and appears useful for large-scale screening of blood donors.

Classification and characterization of immune haemocytes in the larvae of the Indian fritillary, Papilio hyperbius (Lepidopetra: Nymphalidae)

In this study, haemocytes present in Papilio hyperbius Linnaeus were identified and characterized. Six different types of haemocyte were recorded in the haemocoel of this species of insect: prohaemocytes, plasmatocytes, granulocytes, spherulocytes, adipohaemocytes and oenocytoids. Of these the granulocytes were found to be responsible for cell-mediated immune responses such as phagocytosis. Granulocytes that were exposed to immunity inducers (carboxylate-modified polystyrene latex beads [CLBs] and Escherichia coli) had fan-like or pod-like structures on their cell membranes. The lysosomes in granulocytes were activated 2 h after injection with E. coli and after 12 h, all granulocytes exhibited highly activated lysosomes. After 24 and 48 h, the lysosome activity in granulocytes decreased. Transmission electron microscopy revealed that phagocytosis, which was mediated by granulocytes in the early hours of the E. coli infection, led to the formation of one phagosome for one E. coli within the cytosol. Moreover, as time passed, endosomes or lysosomes of different size developed. Subsequently, the phagosomes and lysosomes fused and E. coli were eliminated. After this series of immune responses, the nuclei of the granulocytes were indistinct and their cellular activity decreased. Hence, as old immune cells were replaced by new ones, active and healthy immune haemocytes were presumed to be maintained in the hemocoel.

Venturi pump-critical orifice as an online and robust nanoparticle dilution probe for in situ powder stream characterization

The study of aerosol dynamics in nanomaterial synthesis and powder processing requires real time, fast, automatic and reliable characterization of particle size distribution and concentration. Online characterization techniques, such as the scanning mobility particle sizer (SMPS) allow these measurements for aerosol systems. Unfortunately, the SMPS was developed and optimized primarily for atmospheric sampling. However, reactors for the purposeful synthesis of nanoparticles operate in highly dynamic conditions with high concentrations, various pressures and even flammable, pyrophoric or toxic gases, demanding fast and reliable quenching, diluting and transporting the aerosols towards characterization. In the present work, a sampling and dilution probe based on the Venturi principle with different orifice sizes was characterized using polystyrene latex beads and salt. The obtained dilution rates were compared vs state of the art equations and precursor dilution from a silane reactor showing good agreement. The smallest orifices could clog but ethanol and pressurized gas allow their regeneration. • Study compares dilution probe capabilities on PSL beads, salt and silane vs models. • Probes useful for characterizing & monitoring aerosol reactors and generators. • Particularly attractive in systems with toxic, explosive or pyrophoric atmospheres. • Cheap, operational at different pressures, allows quenching fast aerosol dynamics. • Experiments agree with predictions PSL standard shows advantages over salt.

Matrin3 (MATR3) Expression Is Associated with Hemophagocytosis.

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory syndrome characterized by prolonged fever, cytopenia, hepatosplenomegaly, and hemophagocytosis. This occurs as a result of activated macrophages and impaired function of natural killer cells and/or cytotoxic T lymphocytes. The NF-κB pathway plays a crucial role in hyperinflammation. Matrin3 (MATR3) is a nuclear RNA/DNA-binding protein that plays multiple roles in the regulation of gene expression. We enroll 62 patients diagnosed with secondary HLH and hemophagocytosis. Peripheral blood (PB) from 25 patients and 30 healthy volunteers and good quality bone marrow (BM) samples from 47 patients are collected and used for analysis. Clinical parameters, including age, sex, etiology, ferritin, fibrinogen, triglyceride, and viral infection status, had no association with survival prediction. Patients with downregulation of NF-κB and MATR3mRNA expression in the BM had a higher mortality rate. MATR3mRNA expression in PB was lower in patients compared to that in healthy volunteers. We use shRNA-MATR3-KD-THP1 cells to determine the efficacy of phagocytosis. We note that shRNA-MATR3-KD-THP1 cells had a higher phagocytic effect on necrotic Jurkat E6 cells and carboxylate modified polystyrene latex beads. Herein, we provide evidence of a new marker for clinical translation that can serve as a potential treatment target for secondary HLH.

Magnetically recyclable flake-like BiOI-Fe3O4 microswimmers for fast and efficient degradation of microplastics

Microplastics ubiquitously in the environment endanger both marine organisms and human beings. Currently, the smaller sizes of microplastics in size ranging from 1 µm to 10 µm are likely to pass through the filtration systems in water treatment facilities and present in the drinking water supply. This study proposes a promising method of degrading the 1.1 µm polystyrene latex (PSL) beads microplastics using a self-propelled and magnetically recovered BiOI-Fe3O4 microswimmer. The results reveal flake-like BiOI-Fe3O4 microswimmer successfully degrades 64% polystyrene microplastics in 120 h and reduces the concentration of microplastics in an aqueous solution from 0.05 g/L to 0.018 g/L. The presence of visible light and H2O2 fuel induced the movement of the microswimmer by the decomposition of H2O2 into oxygen bubbles. It is observed that the microswimmer with the mean particle size of 3.913 µm can move at a reasonable speed of 3.0498 µm/s in 5 wt% H2O2 concentration under 3.6 W visible light irradiation. It can be concluded that PSL degrades rapidly when exposed to visible light for less than 24 h.

Focus-engineered sub-diffraction imaging in infrared-sensitive third-order sum frequency generation microscope.

We experimentally demonstrate sub-diffraction imaging in infrared-sensitive third-order sum frequency generation (TSFG) microscope using focal-field engineering technique. The TSFG interaction studied here makes use of two mid infrared photons and a single 1040 nm pump photon to generate up-converted visible photons. Focal field engineering scheme is implemented using a Toraldo-style single annular phase mask imprinted on the 1040 nm beam using a spatial light modulator. The effect of focal field engineered excitation beam on the non-resonant-TSFG process is studied by imaging isolated silicon sub-micron disks and periodic grating structures. Maximum reduction in the measured TSFG central-lobe size by ∼43% with energy in the central lobe of 35% is observed in the presence of phase mask. Maximum contrast improvement of 30% is observed for periodic grating structures. Furthermore, to validate the infrared sensitivity of the focus engineered TSFG microscope, we demonstrate imaging of amorphous Germanium-based guided-mode resonance structures, and polystyrene latex beads probed near the O-H vibrational region. We also demonstrate the utility of the focus engineered TSFG microscope for high resolution imaging of two-dimensional layered material. Focus-engineered TSFG process is a promising imaging modality that combines infrared selectivity with improved resolution and contrast, making it suitable for nanostructure and surface layer imaging.

Coronin 1A is Uniquely Expressed in the Human Follicle Associated Epithelium and is Required For Human M Cell Maturation and Function

IntroductionMicrofold (M) cells are specialized epithelial cells that play an integral role in immune surveillance of the gut luminal environment. They functionally act as gatekeepers within the follicle‐associated epithelium (FAE) of Peyer’s patches to regulate antigen delivery to immune cells of gut‐associated lymphoid tissue. Studies have associated damage in the FAE with chronic inflammatory conditions, such as IBD; however, studies designed to understand how human M cells contribute to disease onset and/or pathogenesis under pathogenic conditions remain incomplete. OBJECTIVE: Since M cells are differentiated from Lgr5+ intestinal stem cells, we proposed to utilize human enteroids to determine the factors that regulate human M cell differentiation and function. Quantitative proteomics analysis of human enteroids differentiated to express M cells revealed enriched expression of coronin 1A, an actin‐remodeling protein involved in phagocytosis and expressed immune cells. Since M cells engulf luminal gut antigens via phagocytosis, we hypothesized that coronin 1A is uniquely expressed in the human FAE and plays a role in gut antigen uptake and transcytosis in human M cells.MethodsHuman ileal enteroids derived from biopsies obtained from healthy donors were grown as monolayers and differentiated (no Wnt3a, R‐spondin‐1) for at least 5 days. To express M cells, cultures were exposed to RANKL and TNF during differentiation. Human expression of coronin 1A was validated by immunoblot and confocal microscopy of ileal biopsies obtained from healthy donors. Stable knockdown (KD) of coronin 1A in human enteroids was achieved by shRNA lentivirus and puromycin selection. M cell monolayers, expressing or lacking coronin 1A, were exposed apically to commensal (HS) and pathogenic strains of E. coli (EPEC, AIEC) to determine the contribution of gut microbes to stimulate M cell transcytosis, as measured by uptake of fluorescent polystyrene latex beads and immunoglobulins.ResultsCoronin 1A was expressed in human enteroid monolayers differentiated to express M cells, but not in monolayers differentiated to mimic the villus epithelium. Similar results were obtained in biopsy sections of the human ileum with coronin 1A detected in the FAE, but not in crypt or villus epithelia. This staining pattern was unique for human, as coronin 1A expression in the mouse ileum was confined to lamina propria and lymphoid follicle immune cells. Coronin 1A KD resulted in decreased expression of glycoprotein 2, a marker of mature M cells, while other markers of the FAE and M cells, including CD14, ICAM1, Spi‐B, SOX8, and FcRN remained unchanged. Coronin 1A KD also resulted in impaired uptake/transcytosis of IgG (via FcRN) as well as pathogen‐stimulated uptake/transcytosis of polystyrene beads by human M cells.ConclusionsThe studies show: (1) human enteroids can be differentiated to model coronin 1A expression in the intact human FAE; (2) coronin 1A expression is necessary for terminal differentiation and function of human M cells; and (3) coronin 1A is required for pathogen‐stimulated uptake and transcytosis of various types of luminal gut cargo. We conclude that M cell‐expressing enteroid monolayers can be used as a relevant human model to further interrogate tropism for host‐pathogen interactions, mechanisms of luminal surveillance, and response to oral vaccine therapies.

Antioxidant colloids via heteroaggregation of cerium oxide nanoparticles and latex beads

Antioxidant colloids were developed via controlled heteroaggregation of cerium oxide nanoparticles (CeO2 NPs) and sulfate-functionalized polystyrene latex (SL) beads. Positively charged CeO2 NPs were directly immobilized onto SL particles of opposite surface charge via electrostatic attraction (SL/Ce composite), while negatively charged CeO2 NPs were initially functionalized with poly(diallyldimethylammonium chloride) (PDADMAC) polyelectrolyte and then, aggregated with the SL particles (SPCe composite). The PDADMAC served to induce a charge reversal on CeO2 NPs, while the SL support prevented nanoparticle aggregation under conditions, where the dispersions of bare CeO2 NPs were unstable. Both SL/Ce and SPCe showed enhanced radical scavenging activity compared to bare CeO2 NPs and were found to mimic peroxidase enzymes. The results demonstrate that SL beads are suitable supports to formulate CeO2 particles and to achieve remarkable dispersion storage stability. The PDADMAC functionalization and immobilization of CeO2 NPs neither compromised the peroxidase-like activity nor the radical scavenging potential. The obtained SL/Ce and SPCe artificial enzymes are foreseen to be excellent antioxidant agents in various applications in the biomedical, food, and cosmetic industries.

Combined Effects of Masking and Distance on Aerosol Exposure Potential

ObjectiveTo quantify the efficacy of masking and “social distancing” on the transmission of airborne particles from a phantom aerosol source (simulating an infected individual) to a nearby target (simulating a healthy bystander) in a well-controlled setting. MethodsAn aerosol was created using monodisperse polystyrene latex beads in place of infectious respiratory secretions. Detection was by aerodynamic particle spectrometry. Both reusable cloth masks and disposable paper masks were studied. Transmission was simulated indoors during a 3-minute interval to eliminate the effect of variable ventilation rate on aerosol exposure. The study commenced on September 16, 2020, and concluded on December 15, 2020. ResultsCompared with a baseline of 1-foot separation with no masks employed, particle count was reduced by 84% at 3 feet of separation and 97% at 6 feet. A modest decrease in particle count was observed when only the receiver was masked. The most substantial exposure reduction occurred when the aerosol source was masked (or both parties were masked). When both the source and target were masked, particle count was reduced by more than 99.5% of baseline, regardless of separation distance or which type of mask was employed. ConclusionThese results support the principle of layered protection to mitigate transmission of SARS-CoV-2, the virus causing COVID-19, and other respiratory viruses and emphasize the importance of controlling the spread of aerosol at its source. The combination of masking and distancing reduced the exposure to exhaled particulates more than any individual measure. Combined measures remain the most effective way to combat the spread of respiratory infection.

Characterization of the immune hemocyte in larvae of Dorcus titanus castanicolor (Motschulsky, 1861) (Lucanidae, Coleoptera)

AbstractThere are four types of hemocytes in the stag beetle hemolymph: granulocytes, prohemocytes, coagulocytes, and spherulocytes. Unusually, the size and shape of the hemocyte subtypes are similar. To identify the predominant immune hemocytes, we injected carboxylate‐modified polystyrene latex beads and E. coli particles into the hemocoel of stag beetles. In response to the pathogens, only granulocytes underwent morphological changes, including the extension of fan (or amoeba)‐like structures from their membrane, and had bacterial particles in their cytoplasm. At 6 h post‐injection, lysosomes in the cytoplasm of the granulocytes were activated to remove the pathogens. At 12 h post‐injection, more lysosomes were activated along with phagocytosis of the E. coli particles. At 24 h to 48 h post‐injection, the bacterial particles, including activated lysosomes, were gradually cleared from the cytoplasm. To confirm these results, we performed flow cytometry analysis. Consistent with our microscope observations, the granulocytes were activated after 6 h post‐infection, and lysosomes were mostly activated at 12 h. These results suggest that bacteria are actively engulfed between 6 and 12 h post‐infection by granulocytes. Granulocyte lysosomes were activated within 12 h to digest the bacteria, which were completely cleared by 48 h post‐infection.

Surface-Enhanced Raman Spectroscopy for Environmental Monitoring of Aerosols

Surface-enhanced Raman spectroscopy (SERS) is conducted from single aerosol particles held in a linear electrodynamic quadrupole trap. SERS measurements from two representative types of ambient aerosol particles, semi-liquid and solid aerosols, are demonstrated; aerosol composed of adenine where the metallic nanoparticles (MNPs) are volume distributed throughout the particle and aerosol composed of polystyrene latex (PSL) beads where the MNPs are surface coated. An enhancement factor > 106 is demonstrated from 5 μm aerosols containing trace amounts of adenine (0.1% by mass), with a detection limit of 10–8 M corresponding to 5 × 105 molecules (equivalent to 100 ag in mass or a 50 nm diameter sphere), and a ratio of 100 adenine molecules per Ag NP. SERS signal intensities are linear with particle adenine concentration up to a saturation point. Both the linearity and enhancement factor were confirmed by SERS measurements of adenine as bulk suspensions. The SERS spectra of adenine as bulk suspensions were explored as a function of excitation wavelength ranging from 400 to 800 nm. The two main Raman peaks of adenine at 738 and 1336 cm–1 exhibit SERS maxima for excitation in the 450–500 nm range for commercially available 40 nm spherical Ag nanoparticles (NPs) used in this study, which shifts to longer wavelengths with the addition of NaCl. Shifts in SERS and spontaneous Raman shifts were observed between aqueous and dry adenine, in agreement with the literature, demonstrating the utility of SERS to possibly study water uptake of aerosols. SERS is measured from MNP surface-coated PSL beads with an enhancement factor of 30 for 5 μm PSLs. Theoretical extrapolation demonstrates that the enhancement factor will increase for decreasing particle size with an estimated enhancement factor of 140 for 1 μm PSLs.

Pendimethalin-based herbicide impairs cellular immune response and haemocyte morphology in a beneficial ground beetle

Herbicides have become the most commonly applied agrochemicals in agroecosystems. Thus, basic knowledge of their physiological effects on insects is needed, especially for understanding their impact on beneficial insect species. In this study, we evaluated the effect of a pendimethalin-based herbicide (PND) on the cellular immune response of the carabid beetle Harpalus (Pseudoophonus) rufipes (De Geer 1774) (Coleoptera, Carabidae), acting as biocontrol agent in agroecosystems. Total and differential haemocyte counts and phagocytosis assay, performed by injecting in vivo carboxylate-modified polystyrene latex beads, were measured in beetles exposed to a recommended field dose (4L per ha) of PND to evaluate the exposure effects over the time. The pattern of haemocyte subpopulations and the decrease of the phagocytic index after the exposure to PND suggested a lowering of P. rufipes ability to face an infection performing a cell-mediated response. PND was also found to cause cytotoxic effects on the haemocyte ultrastructure. Ultrastructural alterations such as irregular shape, large vacuolization of the cytoplasm, and condensation of marginated chromatin were recorded from 2d of exposure. The loss of RER, Golgi apparatus, mitochondria integrity and the swelling of the outer nuclear membrane found in some haemocytes suggested an interference of PND with the membrane permeability. Results indicated that the exposure to PND impairs the distribution, morphology and physiological functions of haemocytes causing a decrease of P. rufipes immunocompetence. Moreover, the sensitivity to herbicide exposure makes this species a suitable model and a useful bioindicator for monitoring exposure effects on non-target species. This study provides useful information to protect and preserve biodiversity of insects in agroecosystems.

Phagocytosis of microparticles increases responsiveness of macrophage-like cell lines U937 and THP-1 to bacterial lipopolysaccharide and lipopeptide

Following bacterial infection, macrophages produce pro-inflammatory cytokines in response to bacterial cell components, including lipopolysaccharide (LPS) and lipopeptide, and simultaneously phagocytize and digest the invading bacteria. To study the effects of phagocytosis on pro-inflammatory responses, we determined if phagocytosis of polystyrene latex beads with ~ 1 µm diameter increases pro-inflammatory cytokine expression by human macrophage-like U937 and THP-1 cells stimulated with LPS. Treating macrophage-like cells with beads coated with IgG to facilitate Fcγ receptor-mediated phagocytosis increased LPS-induced expression of pro-inflammatory cytokines, including tumor necrosis factor-alpha, interleukin-1 beta, and interleukin-6. Treatment with beads coated with poly-l-lysine to facilitate Fcγ receptor–independent phagocytosis also increased LPS-induced cytokine expression. Our results indicate that LPS-induced pro-inflammatory responses are enhanced by bead phagocytosis regardless of the uptake mechanism. Additionally, phagocytosis enhanced LPS-induced NF-κB activation, suggesting that Toll-like receptor (TLR) 4 signaling is enhanced by phagocytosis. Furthermore, bead phagocytosis enhanced pro-inflammatory responses in U937 cells stimulated with lipopeptide, a ligand for the TLR2/TLR6 heterodimeric receptor. In conclusion, microparticle phagocytosis by macrophage-like U937 and THP-1 cells enhances the innate immune response induced by bacterial components.

Effect of human breast milk on innate immune response: Up-regulation of bacterial pattern recognition receptors and innate cytokines in THP-1 monocytic cells

Human breast milk (HBM) contains many bioactive components that protect infants from various microorganisms. Pattern recognition receptors on phagocytic cells recognize microbial pathogens and promote the innate immune system. This study aimed to evaluate the effect of HBM on the expression of pattern recognition receptors and innate cytokines in the monocytic cell line THP-1 and the phagocytic activity of RAW264.7 macrophages. Expression levels of specific mRNAs in THP-1 cells were quantitated using reverse transcription-polymerase chain reaction. Phagocytic activity was measured by fluorescence microscopy to detect the uptake of fluorescent dye-labeled carboxylate-modified polystyrene latex beads in RAW264.7 macrophages. HBM stimulated the phagocytic activity of RAW264.7 macrophages. HBM increased mRNA expression of pattern recognition receptors, including the cluster of differentiation 14 and toll-like receptor 2 and 4, and various innate cytokines, including tumor necrosis factor α, interleukin-1β, C-X-C motif chemokine 8, and C-C motif chemokine ligand 2, in THP-1 monocytic cells. Furthermore, milk oligosaccharides in HBM, such as lacto- N-fucopentaose I, enhanced the expression of pattern recognition receptors and various innate cytokines. HBM is able to modulate the innate immune response by upregulating the expression of pattern recognition receptors and various innate cytokines in monocytes/macrophages.

Design and site-directed immobilization of single-chain Fv antibody to polystyrene latex beads via material-binding peptides and application to latex turbidimetric assay

In this study, immobilization of single-chain Fv (scFv) antibodies on the surfaces of polystyrene (PS) latex beads via material-binding peptides was investigated for sensitive immuno-turbidimetric assay of C-reactive protein (CRP). Anti-CRP scFvs fused with polystyrene-binding peptide (PS-tag) and poly(methylmethacrylate)-binding peptide (PMMA-tag) were over-expressed in Escherichiacoli cells and recovered in the active form following refolding. The beads with PMMA-tag-fused scFv (scFv-PM) were successfully suspended with sufficient dispersion at pH 8.0. Three types of alternative scFv-PMs with a penta-asparatic acid tag (D5-tag) introduced at different positions were then designed. All of the D5-tagged scFv-PMs were successfully immobilized on the surfaces of beads with no significant change in the diameter of the latex beads at pH levels ranging from 6.0 to 8.0. According to the results of turbidimetric assay for the detection of CRP, 13ng/ml of CRP was detectable using beads with D5-tagged scFv-PMs at 400ng/cm3, and no turbidity change was observed in the absence of antigen. When the density of scFv-PM was 250ng/cm2, which was 63% of the maximum density, the beads were dispersed well and reactive with the antigen at a concentration range comparable to those with D5-tagged scFv-PMs. These results indicate that controlling charge density on the surface of beads after site-directed immobilization is definitely important in order to maintain high levels of dispersion and reactivity. Thus, the usefulness of the scFv-PM as well as D5-tagged scFv-PMs developed in the present study should be significant when used as ligand antibodies in the preparation of immuno-latex beads.

Hybrid microgels produced via droplet microfluidics for sustainable delivery of hydrophobic and hydrophilic model nanocarriers.

Drug delivery for treatment of chronic diseases relies on the effective delivery of payload materials into the target cells in a long-term release. In this context, the present study investigated hybrid microgels as platforms to carry nanoparticles to drug delivery. Hybrid microgels were produced with silk fibroin (SF) and chondroitin sulfate (CS), and alginate (ALG) by droplet microfluidics. ALG/SF, ALG/CS, and ALG/CS/SF microgels, ranging from 70-90μm, were tested to encapsulate two model nanoparticles, polystyrene latex beads in pristine form (NPs) and NPs coated with bovine serum albumin (NPs-BSA) to simulate hydrophobic and hydrophilic nanocarriers, respectively. IR spectroscopy and fluorescence microscopy analysis confirmed the presence of SF and CS within ALG-based microgels revealing marked differences in their morphology and physicochemical properties. The release profiles of model nanoparticles revealed to be dependent on microgels composition and physicochemical properties. These findings show that SF ternary hybrid microgels facilitated the entrapment of hydrophobic nanocarriers with encapsulation efficiency (EE) from 83 to 98% keeping a better sustainable profile release than nonhybrid ALG microgels. Besides, CS improved the carriage of NPs-BSA (EE=85%) and their profile release. The results highlight the versatility and tunable properties of these biobased microgels, being a good strategy to be used as an efficient platform in using macro and nanoencapsulated systems for drug delivery.

The Giant Nucleus Impactor (GNI)—A System for the Impaction and Automated Optical Sizing of Giant Aerosol Particles with Emphasis on Sea Salt. Part I: Basic Instrument and Algorithms

AbstractSize distributions of giant aerosol particles (dry radius larger than 0.5μm, sometimes referred to as coarse-mode aerosol particles) are not well characterized in the atmosphere. Measurements are problematic for these particles because they (i) occur in low concentrations, (ii) have difficulty in passing through air inlets, (iii) may be dry or deliquesced particles, and (iv) if sampled by impaction, typically require labor-intensive methods. In this study, a simple, high-volume impaction system called the Giant Nucleus Impactor (GNI), based on free-stream exposure of polycarbonate slides from aircraft, is described along with an automated optical microscope–based system for analysis of the impacted particles. The impaction slides are analyzed in a humidity-controlled chamber (typically 90% relative humidity) that ensures deliquescence of soluble (typically sea salt) particles. A computer-controlled optical microscope with two digital cameras is used to acquire and analyze images of the aerosol particles. At relative humidities above deliquescence (74% RH for sea salt), such particles will form near-spherical cap solution drops on the polycarbonate slides. The sea-salt mass in each giant aerosol particle is then calculated using simple geometry and published water activity measurements. The system has a sample volume of about 10 L s−1at aircraft speeds of 105 m s−1. For salt particles, the measurement range is from about 0.7μm dry radius to at least 16μm dry radius, with a size-bin resolution of 0.2μm dry radius. The sizing accuracy was tested using polystyrene latex (PSL) beads of known size.

Performance of Two Different Techniques to Concentrate Samples for Bioaerosol Quantification

We evaluated two concentrating techniques that could be used to improve bioaerosol detection and quantification: A BioChromato Smart Evaporator C1 (BioChromato, Inc.) and two Concentrating Pipette (CP) models (CP-150 and CP-Select) (InnovaPrep, LLC). We determined the concentration factor (CF) (the concentration of particles in the final solution compared to the concentration in the initial solution) and the particle losses when processing the samples with polystyrene latex (PSL) beads and different species of bacteria. When processing total particles, regardless of the culturability status, the losses for the Evaporator were 3.70–23.89%; for the CP-models, the losses ranged from 0.20% to 67.22%. For the culturable particles processed with the CP devices, the losses ranged from 42.85% to 90.19% and were higher for Gram-negative pseudomonads compared to Gram-positive B. subtilis. Despite the loss of particles, both devices yielded more concentrated final solutions. The CF for the Evaporator was 3.59–10.92; the CF values for the CP devices ranged from 55.77 to 184.64 for total particles and from 6.29 to 96.52 for culturable bacteria. This higher CF was mainly achieved due to lower final suspension volumes. The study demonstrated that the two concentrators can improve particle detection, but that one should take particle losses into account.

Chicken CATH-2 Increases Antigen Presentation Markers on Chicken Monocytes and Macrophages.

: BackgroundCathelicidins are a family of Host Defense Peptides (HDPs), that play an important role in the innate immune response. They exert both broad-spectrum antimicrobial activity against pathogens, and strong immunomodulatory functions that affect the response of innate and adaptive immune cells.ObjectiveThe aim of this study was to investigate immunomodulation by the chicken cathelicidin CATH-2 and compare its activities to those of the human cathelicidin LL-37.MethodsChicken macrophages and chicken monocytes were incubated with cathelicidins. Activation of immune cells was determined by measuring surface markers Mannose Receptor C-type 1 (MRC1) and MHC-II. Cytokine production was measured by qPCR and nitric oxide production was determined using the Griess assay. Finally, the effect of cathelicidins on phagocytosis was measured using carboxylate-modified polystyrene latex beads.ResultsCATH-2 and its all-D enantiomer D-CATH-2 increased MRC1 and MHC-II expression, markers for antigen presentation, on primary chicken monocytes, whereas LL-37 did not. D-CATH-2 also increased the MRC1 and MHC-II expression if a chicken macrophage cell line (HD11 cells) was used. In addition, LPS-induced NO production by HD11 cells was inhibited by CATH-2 and D-CATH-2.ConclusionThese results are a clear indication that CATH-2 (and D-CATH-2) affect the activation state of monocytes and macrophages, which leads to optimization of the innate immune response and enhancement of the adaptive immune response.