The coalescence between growing droplets is important for the surface coverage and spatial arrangements of droplets on surfaces. In this work, total internal reflection fluorescence (TIRF) microscopy is utilized to in situ investigate the formation of nanodroplets around the rim of a polymer microcap, with sub-micron spatial and millisecond temporal resolution. We observe that the coalescence among droplets occurs frequently during their growth by solvent exchange. Our experimental results show that the position of the droplet from two merged droplets is related to the size of the parent droplets. The position of the coalesced droplet and the ratio of parent droplet sizes obey a scaling law, reflecting a coalescence preference based on the size inequality. As a result of droplet coalescence, the angles between the centroids of two neighbouring droplets increase with time, obeying a nearly symmetrical arrangement of droplets at various time intervals. The evolution of the position and number from coalescence of growing droplets is modelled. The mechanism for coalescence driven self-organization of growing droplets is general, applicable to microcaps of different sizes and droplets of different liquids. The understanding from this work may be valuable for positioning nanodroplets by nucleation and growth without using templates.
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Metab Brain Dis
January 2025
Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Hale Building for Transformative Medicine, Room 10006, 60 Fenwood Road, Boston, MA, 02115, USA.
α-Synuclein (αS) is a 140 amino-acid neuronal protein highly enriched in presynaptic nerve terminals. Its progressive accumulation in Lewy bodies and neurites is the hallmark of Parkinson's disease (PD). A growing number of studies highlights a critical interplay between lipid metabolism and αS biology.
View Article and Find Full Text PDFUltrason Sonochem
January 2025
School of Engineering Computing and Mathematics, Oxford Brookes University, Oxford, UK; Department of Materials, University of Oxford, Oxford, UK.
This study experimentally investigates the role of cavitation-induced shock waves in initiating and destabilizing capillary (surface) waves on a droplet surface, preceding atomization. Acoustic emissions and interfacial wave dynamics were simultaneously monitored in droplets of different liquids (water, isopropyl alcohol and glycerol), using a calibrated fiber-optic hydrophone and high-speed imaging. Spectral analysis of the hydrophone data revealed distinct subharmonic frequency peaks in the acoustic spectrum correlated with the wavelength of capillary waves, which were optically captured during the onset of atomization from the repetitive imploding bubbles.
View Article and Find Full Text PDFSci Rep
January 2025
Aerosol Technology Laboratory, Biological and Agricultural Engineering Department, Texas A&M University, College Station, TX, 77843, USA.
Gram-negative bacteria pose an increased threat to public health because of their ability to evade the effects of many antimicrobials with growing antibiotic resistance globally. One key component of gram-negative bacteria resistance is the functionality and the cells' ability to repair the outer membrane (OM) which acts as a barrier for the cell to the external environment. The biosynthesis of lipids, particularly lipopolysaccharides, or lipooligosaccharides (LPS/LOS) is essential for OM repair.
View Article and Find Full Text PDFAppl Environ Microbiol
January 2025
McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas, USA.
Electroactive organisms contribute to metal cycling, pollutant removal, and other redox-driven environmental processes via extracellular electron transfer (EET). Unfortunately, developing genotype-phenotype relationships for electroactive organisms is challenging because EET is necessarily removed from the cell of origin. Microdroplet emulsions, which encapsulate individual cells in aqueous droplets, have been used to study a variety of extracellular phenotypes but have not been applied to investigate EET.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
Department of Food Engineering and Technology, Institute of Biosciences, Humanities and Exact Sciences, São Paulo State University (UNESP), Street Cristóvão Colombo, 2265, São José do Rio Preto 15054-000, Brazil. Electronic address:
In response to the growing need to expand the knowledge base on novel, more sustainable protein sources, this study investigated the effectiveness of cowpea protein concentrate (CPC) as a natural emulsifying agent, examining the relationships between pH (3-11), oil concentration (2-10 %), and emulsion stability. pH and oil concentration significantly impacted droplet size distribution, with uniformity decreasing in the order of pH 9 > pH 11 > pH 7, which was attributed to droplet coalescence and flocculation. As evidenced by circular dichroism, alkalinity induced a slight increase in the beta-sheet content of CPC, while simultaneously reducing the alpha-helix content.
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