scholarly journals Water uptake of subpollen aerosol particles: hygroscopic growth, CCN activation, and liquid-liquid phase separation

2020 ◽  
Author(s):  
Eugene F. Mikhailov ◽  
Mira L. Pöhlker ◽  
Kathrin Reinmuth-Selzle ◽  
Sergey S. Vlasenko ◽  
Ovid O. Krüger ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Water Uptake ◽  
Chemical Reactivity ◽  
Fine Fraction ◽  
Liquid Phase Separation ◽  
Hygroscopic Growth ◽  
Model Calculations ◽  
Wide Range ◽  
Liquid Liquid Phase Separation

Abstract. Pollen grains emitted from vegetation can release subpollen particles (SPP) that contribute to the fine fraction of atmospheric aerosols and may act as cloud condensation nuclei (CCN), ice nuclei (IN), or aeroallergens. Here, we investigate and characterize the hygroscopic growth and CCN activation of birch, pine, and rapeseed SPP. A high humidity tandem differential mobility analyzer (HHTDMA) was used to measure particle restructuring and water uptake over a wide range of relative humidity (RH) from 2 % to 99.5 %, and a continuous flow CCN counter was used for size-resolved measurements of CCN activation at supersaturations (S) in the range of 0.2 % to 1.2 %. For both, subsaturated and supersaturated conditions, effective hygroscopicity parameters κ, were obtained by Köhler model calculations. Gravimetric and chemical analyses, electron microscopy, and dynamic light scattering measurements were performed to characterize further properties of SPP from aqueous pollen extracts such as chemical composition (starch, proteins, DNA, and inorganic ions) and the hydrodynamic size distribution of water-insoluble material. All investigated SPP samples exhibited sharp increases of water uptake and κ above ~95 % RH, suggesting a liquid-liquid phase separation (LLPS). The HHTDMA measurements at RH > 95 % enable closure between the CCN activation at water vapor supersaturation and hygroscopic growth at subsaturated conditions, which is often not achieved when HTDMA measurements are performed at lower RH where the water uptake and effective hygroscopicity may be limited by the effects of LLPS. Such effects may be important not only for closure between hygroscopic growth and CCN activation but also for the chemical reactivity, allergenic potential, and related health effects of SPP.

Water uptake of subpollen aerosol particles: hygroscopic growth, CCN activation, and liquid-liquid phase separation

2021 ◽  
Author(s):  
Eugene Mikhailov ◽  
Mira Pöhlker ◽  
Kathrin Reinmuth-Selzle ◽  
Sergey Vlasenko ◽  
Christopher Pöhlker ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Water Uptake ◽  
Chemical Reactivity ◽  
Fine Fraction ◽  
Liquid Phase Separation ◽  
Hygroscopic Growth ◽  
Model Calculations ◽  
Wide Range ◽  
Liquid Liquid Phase Separation

<p>Pollen grains emitted from vegetation can release subpollen particles (SPP) that contribute to the fine fraction of atmospheric aerosols and may act as cloud condensation nuclei (CCN), ice nuclei (IN), or aeroallergens. Here, we investigate and characterize the hygroscopic growth and CCN activation of birch, pine, and rapeseed SPP. A high humidity tandem differential mobility analyzer (HHTDMA) was used to measure particle restructuring and water uptake over a wide range of relative humidity (RH) from 2 % to 99.5 %, and a continuous flow CCN counter was used for size-resolved measurements of CCN activation at supersaturations (S) in the range of 0.2 % to 1.2 %. For both subsaturated and supersaturated conditions, effective hygroscopicity parameters к , were obtained by Köhler model calculations. Gravimetric and chemical analyses, electron microscopy, and dynamic light scattering measurements were performed to characterize further properties of SPP from aqueous pollen extracts such as chemical composition (starch, proteins, DNA, and inorganic ions) and the hydrodynamic size distribution of water-insoluble material. All investigated SPP samples exhibited a sharp increase of water uptake and k above ~95 % RH, suggesting a liquid-liquid phase separation (LLPS). The HHTDMA measurements at RH> 95% enable closure between the CCN activation at water vapor supersaturation and hygroscopic growth at subsaturated conditions, which is often not achieved when HTDMA measurements are performed at lower RH where the water uptake and effective hygroscopicity may be limited by the effects of LLPS. Such effects may be important not only for closure between hygroscopic growth and CCN activation but also for the chemical reactivity, allergenic potential, and related health effects of SPP.</p><p>This research has been supported by the Russian Science Foundation (grant no. 18-10 17-00076) and Max Planck Society.</p>

scholarly journals Water uptake of subpollen aerosol particles: hygroscopic growth, cloud condensation nuclei activation, and liquid–liquid phase separation

2021 ◽  
Vol 21 (9) ◽  
pp. 6999-7022
Author(s):  
Eugene F. Mikhailov ◽  
Mira L. Pöhlker ◽  
Kathrin Reinmuth-Selzle ◽  
Sergey S. Vlasenko ◽  
Ovid O. Krüger ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Water Uptake ◽  
Cloud Condensation Nuclei ◽  
Liquid Phase Separation ◽  
Hygroscopic Growth ◽  
Differential Mobility Analyzer ◽  
Condensation Nuclei ◽  
Differential Mobility ◽  
Liquid Liquid Phase Separation

Abstract. Pollen grains emitted from vegetation can release subpollen particles (SPPs) that contribute to the fine fraction of atmospheric aerosols and may act as cloud condensation nuclei (CCN), ice nuclei (IN), or aeroallergens. Here, we investigate and characterize the hygroscopic growth and CCN activation of birch, pine, and rapeseed SPPs. A high-humidity tandem differential mobility analyzer (HHTDMA) was used to measure particle restructuring and water uptake over a wide range of relative humidity (RH) from 2 % to 99.5 %, and a continuous flow CCN counter was used for size-resolved measurements of CCN activation at supersaturations (S) in the range of 0.2 % to 1.2 %. For both subsaturated and supersaturated conditions, effective hygroscopicity parameters, κ, were obtained by Köhler model calculations. Gravimetric and chemical analyses, electron microscopy, and dynamic light scattering measurements were performed to characterize further properties of SPPs from aqueous pollen extracts such as chemical composition (starch, proteins, DNA, and inorganic ions) and the hydrodynamic size distribution of water-insoluble material. All investigated SPP samples exhibited a sharp increase of water uptake and κ above ∼95 % RH, suggesting a liquid–liquid phase separation (LLPS). The HHTDMA measurements at RH >95 % enable closure between the CCN activation at water vapor supersaturation and hygroscopic growth at subsaturated conditions, which is often not achieved when hygroscopicity tandem differential mobility analyzer (HTDMA) measurements are performed at lower RH where the water uptake and effective hygroscopicity may be limited by the effects of LLPS. Such effects may be important not only for closure between hygroscopic growth and CCN activation but also for the chemical reactivity, allergenic potential, and related health effects of SPPs.

scholarly journals Liquid-liquid phase separation and viscosity within secondary organic aerosol generated from diesel fuel vapors

2019 ◽  
Author(s):  
Mijung Song ◽  
Adrian M. Maclean ◽  
Yuanzhou Huang ◽  
Natalie R. Smith ◽  
Sandra L. Blair ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Diesel Fuel ◽  
Diffusion Coefficients ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Liquid Phase Separation ◽  
Small Diffusion ◽  
Wide Range ◽  
Liquid Liquid Phase Separation

Abstract. Information on liquid-liquid phase separation (LLPS) and viscosity (or diffusion) within secondary organic aerosol (SOA) is needed to improve predictions of particle size, mass, reactivity, and cloud nucleating properties in the atmosphere. Here we report on LLPS and viscosities within SOA generated by the photooxidation of diesel fuel vapors. Diesel fuel contains a wide range of volatile organic compounds, and SOA generated by the photooxidation of diesel fuel vapors may be a good proxy for SOA from anthropogenic emissions. In our experiments, LLPS occurred over the relative humidity (RH) range of ~ 70 % to ~ 100 %, resulting in an organic-rich outer phase and a water-rich inner phase. These results may have implications for predicting the cloud nucleating properties of anthropogenic SOA since the organic-rich outer phase can lower the kinetic barrier for activation to a cloud droplet. At ≤ 10 % RH, the viscosity was in the range of ≥ 1 × 108 Pa s, which corresponds to roughly the viscosity of tar pitch. At 38–50 % RH the viscosity was in the range of 1 × 108–3 × 105 Pa s. These measured viscosities are consistent with predictions based on oxygen to carbon elemental ratio (O : C) and molar mass as well as predictions based on the number of carbon, hydrogen, and oxygen atoms. Based on the measured viscosities and the Stokes–Einstein relation, at ≤ 10 % RH diffusion coefficients of organics within diesel fuel SOA is ≤ 5.4 × 10−17cm2 s−1 and the mixing time of organics within 200 nm diesel fuel SOA particles (τmixing) is ≳ 50 h. These small diffusion coefficients and large mixing times may be important in laboratory experiments, where SOA is often generated and studied using low RH conditions and on time scales of minutes to hours. At 38–50 % RH, the calculated organic diffusion coefficients are in the range of 5.4 × 10−17 to 1.8 × 10−13 cm2 s−1 and calculated τmixing values are in the range of ~ 0.01 h to ~ 50 h. These values provide important constraints for the physicochemical properties of anthropogenic SOA.

scholarly journals Liquid–liquid phase separation and viscosity within secondary organic aerosol generated from diesel fuel vapors

2019 ◽  
Vol 19 (19) ◽  
pp. 12515-12529 ◽  
Author(s):  
Mijung Song ◽  
Adrian M. Maclean ◽  
Yuanzhou Huang ◽  
Natalie R. Smith ◽  
Sandra L. Blair ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Diesel Fuel ◽  
Diffusion Coefficients ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Liquid Phase Separation ◽  
Small Diffusion ◽  
Wide Range ◽  
Liquid Liquid Phase Separation

Abstract. Information on liquid–liquid phase separation (LLPS) and viscosity (or diffusion) within secondary organic aerosol (SOA) is needed to improve predictions of particle size, mass, reactivity, and cloud nucleating properties in the atmosphere. Here we report on LLPS and viscosities within SOA generated by the photooxidation of diesel fuel vapors. Diesel fuel contains a wide range of volatile organic compounds, and SOA generated by the photooxidation of diesel fuel vapors may be a good proxy for SOA from anthropogenic emissions. In our experiments, LLPS occurred over the relative humidity (RH) range of ∼70 % to ∼100 %, resulting in an organic-rich outer phase and a water-rich inner phase. These results may have implications for predicting the cloud nucleating properties of anthropogenic SOA since the presence of an organic-rich outer phase at high-RH values can lower the supersaturation with respect to water required for cloud droplet formation. At ≤10 % RH, the viscosity was ≥1×108 Pa s, which corresponds to roughly the viscosity of tar pitch. At 38 %–50 % RH, the viscosity was in the range of 1×108 to 3×105 Pa s. These measured viscosities are consistent with predictions based on oxygen to carbon elemental ratio (O:C) and molar mass as well as predictions based on the number of carbon, hydrogen, and oxygen atoms. Based on the measured viscosities and the Stokes–Einstein relation, at ≤10 % RH diffusion coefficients of organics within diesel fuel SOA is ≤5.4×10-17 cm2 s−1 and the mixing time of organics within 200 nm diesel fuel SOA particles (τmixing) is 50 h. These small diffusion coefficients and large mixing times may be important in laboratory experiments, where SOA is often generated and studied using low-RH conditions and on timescales of minutes to hours. At 38 %–50 % RH, the calculated organic diffusion coefficients are in the range of 5.4×10-17 to 1.8×10-13 cm2 s−1 and calculated τmixing values are in the range of ∼0.01 h to ∼50 h. These values provide important constraints for the physicochemical properties of anthropogenic SOA.

scholarly journals Three archetypical classes of macromolecular regulators of protein liquid–liquid phase separation

2019 ◽  
Vol 116 (39) ◽  
pp. 19474-19483 ◽  
Author(s):  
Archishman Ghosh ◽  
Konstantinos Mazarakos ◽  
Huan-Xiang Zhou
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Computational Study ◽  
Quantitative Measure ◽  
Liquid Phase Separation ◽  
Wide Range ◽  
Regulatory Effects ◽  
High Concentrations ◽  
Droplet Phase ◽  
Liquid Liquid Phase Separation

Membraneless organelles, corresponding to the droplet phase upon liquid–liquid phase separation (LLPS) of protein or protein–RNA mixtures, mediate myriad cellular functions. Cells use a variety of biochemical signals such as expression level and posttranslational modification to regulate droplet formation and dissolution, but the physical basis of the regulatory mechanisms remains ill-defined and quantitative assessment of the effects is largely lacking. Our computational study predicted that the strength of attraction by droplet-forming proteins dictates whether and how macromolecular regulators promote or suppress LLPS. We experimentally tested this prediction, using the pentamers of SH3 domains and proline-rich motifs (SH35 and PRM5) as droplet-forming proteins. Determination of the changes in phase boundary and the partition coefficients in the droplet phase over a wide range of regulator concentrations yielded both a quantitative measure and a mechanistic understanding of the regulatory effects. Three archetypical classes of regulatory effects were observed. Ficoll 70 at high concentrations indirectly promoted SH35–PRM5 LLPS, by taking up volume in the bulk phase and thereby displacing SH35 and PRM5 into the droplet phase. Lysozyme had a moderate partition coefficient and suppressed LLPS by substituting weaker attraction with SH35 for the stronger SH35–PRM5 attraction in the droplet phase. By forming even stronger attraction with PRM5, heparin at low concentrations partitioned heavily into the droplet phase and promoted LLPS. These characteristics were recapitulated by computational results of patchy particle models, validating the identification of the 3 classes of macromolecular regulators as volume-exclusion promotors, weak-attraction suppressors, and strong-attraction promotors.

scholarly journals Observations on hygroscopic growth and phase transitions of mixed 1, 2, 6-hexanetriol/(NH4</sub>)<sub>2</sub>SO<sub>4</sub> particles: Investigation of liquid-liquid phase separation (LLPS) dynamic process and mechanism and secondary LLPS

2021 ◽  
Author(s):  
Shuai-Shuai Ma ◽  
Zhe Chen ◽  
Shu-Feng Pang ◽  
Yun-Hong Zhang
Keyword(s):  
Phase Transitions ◽  
Phase Separation ◽  
Liquid Phase ◽  
Liquid Phase Separation ◽  
Solution Phase ◽  
High Time Resolution ◽  
Hygroscopic Growth ◽  
Inorganic Particles ◽  
Inorganic Components ◽  
Liquid Liquid Phase Separation

Abstract. Atmospheric aerosols consisting of organic and inorganic components may undergo liquid-liquid phase separation (LLPS) and liquid-solid phase transitions during ambient relative humidity (RH) fluctuation. However, the knowledge of dynamic phase evolution processes for mixed organic-inorganic particles is scarce. Here we present a universal and visualized observation on LLPS, efflorescence and deliquescence transitions as well as hygroscopic growth of mixed 1, 2, 6-hexanetriol/ammonium sulfate (AS) particles with different organic-inorganic mole ratios (OIR = 1:4, 1:2, 1:1, 2:1 and 4:1) with the high time resolution (0.5 s), using an optical microscope with a video camera. The optical images suggest that an inner AS solution phase is surrounded by an outer organic-rich phase after LLPS for all mixed particles. The LLPS mechanism for particles with different OIRs differs, meanwhile, multiple mechanisms may dominate successively in individual particles with a certain OIR, somewhat inconsistent with earlier observations by literature. More importantly, another phase separation in inner AS solution phase, defined as secondary LLPS here, is observed for OIR = 1:1, 1:2 and 1:4 particles. The secondary LLPS may be attributed to the formation of more concentrated AS inclusions in the inner phase, and becomes more obvious with decreasing RH and increasing AS mole fraction. Furthermore, the changes in size and amount of AS inclusions during LLPS are quantitatively characterized, which further illustrate the equilibrium partitioning process of organic and inorganic components. The experimental results have significant implications for revelation of complex phase transitions of internally mixed atmospheric particles and evaluation of liquid-liquid and liquid-solid equilibria in thermodynamic models.

scholarly journals CRISPR-based DNA and RNA detection with liquid-liquid phase separation

2018 ◽  
Author(s):  
Willem Kasper Spoelstra ◽  
Jeroen M. Jacques ◽  
Franklin L. Nobrega ◽  
Anna C. Haagsma ◽  
Marileen Dogterom ◽  
...  
Keyword(s):  
Phase Separation ◽  
Nucleic Acid ◽  
Liquid Phase ◽  
Clinical Diagnostics ◽  
Liquid Phase Separation ◽  
Molecular Diagnostic ◽  
Target Sequence ◽  
Dna And Rna ◽  
Wide Range ◽  
Liquid Liquid Phase Separation

AbstractThe ability to detect specific nucleic acid sequences allows for a wide range of applications including identification of pathogens, clinical diagnostics, and genotyping. CRISPR-Cas proteins Cas12a and Cas13a are RNA-guided endonucleases that bind and cleave specific DNA and RNA sequences, respectively. After recognition of a target sequence both enzymes activate a unique, indiscriminate nucleic acid cleavage activity, which has been exploited for detection of sequence specific nucleotides using labelled reporter molecules. We here present a label-free detection approach that uses a readout based on solution turbidity caused by liquid-liquid phase separation (LLPS). Turbidity arises from coacervates of positively charged polyelectrolytes with long poly(dT) or poly(U) oligonucleotides. In the presence of a target sequence, long oligonucleotides are progressively shortened, changing the solution from turbid to transparent. We explain how oligonucleotide cleavage resolves LLPS by using a mathematical model which we validate with poly(dT) phase separation experiments. The deployment of LLPS complements CRISPR-based molecular diagnostic applications and facilitates easy and low-cost nucleotide sequence detection.

scholarly journals Observations on hygroscopic growth and phase transitions of mixed 1, 2, 6-hexanetriol ∕ (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub> particles: investigation of the liquid–liquid phase separation (LLPS) dynamic process and mechanism and secondary LLPS during the dehumidification

2021 ◽  
Vol 21 (12) ◽  
pp. 9705-9717
Author(s):  
Shuaishuai Ma ◽  
Zhe Chen ◽  
Shufeng Pang ◽  
Yunhong Zhang
Keyword(s):  
Phase Transitions ◽  
Phase Separation ◽  
Liquid Phase ◽  
Liquid Phase Separation ◽  
Solution Phase ◽  
High Time Resolution ◽  
Hygroscopic Growth ◽  
Inorganic Particles ◽  
Inorganic Components ◽  
Liquid Liquid Phase Separation

Abstract. Atmospheric aerosols consisting of organic and inorganic components may undergo liquid–liquid phase separation (LLPS) and liquid–solid phase transitions during ambient relative humidity (RH) fluctuation. However, the knowledge of dynamic phase evolution processes for mixed organic–inorganic particles is scarce. Here we present a universal and visualized observation of LLPS, efflorescence and deliquescence transitions as well as hygroscopic growth of laboratory-generated mixed 1, 2, 6-hexanetriol / ammonium sulfate (AS) particles with different organic–inorganic mole ratios (OIR = 1:4, 1:2, 1:1, 2:1 and 4:1) with high time resolution (0.5 s) using an optical microscope operated with a video camera. The optical images suggest that an inner AS solution phase is surrounded by an outer organic-rich phase after LLPS for all mixed particles. The LLPS mechanism for particles with different OIRs is found to be distinct; meanwhile, multiple mechanisms may dominate successively in individual particles with a certain OIR, somewhat inconsistently with previously reported observations. More importantly, another phase separation in the inner AS solution phase, defined as secondary LLPS here, is observed for OIR = 1:1, 1:2 and 1:4 particles. The secondary LLPS may be attributed to the formation of more concentrated AS inclusions in the inner phase and becomes more obvious with decreasing RH and increasing AS mole fraction. Furthermore, the changes in size and number of AS inclusions during LLPS are quantitatively characterized, which further illustrate the equilibrium partitioning process of organic and inorganic components. These experimental results have significant implications for the revelation of complex phase transitions of internally mixed atmospheric particles and evaluation of liquid–liquid and liquid–solid equilibria in thermodynamic models.

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