9 research outputs found
Law of corresponding states for osmotic swelling of vesicles
As solute molecules permeate into a vesicle due to a concentration difference
across its membrane, the vesicle swells through osmosis. The swelling can be
divided into two stages: (a) an "ironing" stage, where the volume-to-area ratio
of the vesicle increases without a significant change in its area; (b) a
stretching stage, where the vesicle grows while remaining essentially
spherical, until it ruptures. We show that the crossover between these two
stages can be represented as a broadened continuous phase transition.
Consequently, the swelling curves for different vesicles and different
permeating solutes can be rescaled into a single, theoretically predicted,
universal curve. Such a data collapse is demonstrated for giant unilamellar
POPC vesicles, osmotically swollen due to the permeation of urea, glycerol, or
ethylene glycol. We thereby gain a sensitive measurement of the solutes'
membrane permeability coefficients, finding a concentration-independent
coefficient for urea, while those of glycerol and ethylene glycol are found to
increase with solute concentration. In addition, we use the width of the
transition, as extracted from the data collapse, to infer the number of
independent bending modes that affect the thermodynamics of the vesicle in the
transition region.Comment: 10 page
Hybridosomes from spruce needle homogenate
Introduction: Being of compatible structure with biomembranes, lipid–based nanoparticles are considered
as convenient platforms for drug delivery systems. In the proposed work we considered formation of lipid
nanovesicles associated with bioactive phytochemicals from spruce needle homogenate (here called
hybridosomes). We formed hybridosomes by mixing appropriate amounts of lecithin, supernatant of isolation
of extracellular particles from spruce needle homogenate and glycerol.
Methods: We visualized hybridosomes by light microscopy and cryogenic transmission electron microscopy
and assessed them by flow cytometry, dynamic light scattering, ultraviolet–visual spectroscopy and
interferometric microscopy.
Results: We found that the particles consisted of a bilayer membrane and a fluid-like interior. Flow cytometry
and interferometric light microscopy measurements showed that the majority of the particles were
nano-sized. Dynamic light scattering and interferometric light microscopy measurements agreed well with the
determined average hydrodynamic radius of the particles Rh (between 140 and 180 nm) while their number
densities were in the range between 10^13 and 10^14/mL indicating that hybridosomes present about 2/3 of the
mixture, excluding solvent and other small molecules.
Discussion: Simple and low-cost preparation method, non-demanding saving process and efficient
formation procedure suggest that large scale production of hybridosomes from lipids and spruce needle
homogenate is feasible.Small New World 2.0 4-5 September 2023., Graz, Austri
Hybridosomes from spruce needle homogenate
Introduction: Being of compatible structure with biomembranes, lipid–based nanoparticles are considered
as convenient platforms for drug delivery systems. In the proposed work we considered formation of lipid
nanovesicles associated with bioactive phytochemicals from spruce needle homogenate (here called
hybridosomes). We formed hybridosomes by mixing appropriate amounts of lecithin, supernatant of isolation
of extracellular particles from spruce needle homogenate and glycerol.
Methods: We visualized hybridosomes by light microscopy and cryogenic transmission electron microscopy
and assessed them by flow cytometry, dynamic light scattering, ultraviolet–visual spectroscopy and
interferometric microscopy.
Results: We found that the particles consisted of a bilayer membrane and a fluid-like interior. Flow cytometry
and interferometric light microscopy measurements showed that the majority of the particles were
nano-sized. Dynamic light scattering and interferometric light microscopy measurements agreed well with the
determined average hydrodynamic radius of the particles Rh (between 140 and 180 nm) while their number
densities were in the range between 10^13 and 10^14/mL indicating that hybridosomes present about 2/3 of the
mixture, excluding solvent and other small molecules.
Discussion: Simple and low-cost preparation method, non-demanding saving process and efficient
formation procedure suggest that large scale production of hybridosomes from lipids and spruce needle
homogenate is feasible.Small New World 2.0 4-5 September 2023., Graz, Austri
Electroformation in a flow chamber with solution exchange as a means of preparation of flaccid giant vesicles
A recently described technique (Estes and Mayer, Biochim. Biophys. Acta 1712
(2005) 152--160) for the preparation of giant unilamellar vesicles (GUVs) in
solutions with high ionic strength is examined. By observing a series of
osmotic swellings followed by vesicle bursts upon a micropipette transfer of a
single POPC GUV from a sucrose solution into an isoosmolar glycerol solution, a
value for the permeability of POPC membrane for glycerol, P = (2.09+/-0.82) x
10^{-8} m/s, has been obtained. Based on this result, an alternative mechanism
is proposed for the observed exchange of vesicle interior. With modifications,
the method of Estes and Mayer is then applied to preparation of flaccid GUVs.Comment: 13 pages, 10 figures, accepted for publication in Colloids and
Surfaces B: Biointerface
Characterization of Nanohybridosomes from Lipids and Spruce Homogenate Containing Extracellular Vesicles
Introduction: Lipid nanovesicles associated with bioactive phytochemicals from spruce needle homogenate (here called nano-sized
hybridosomes or nanohybridosomes, NSHs) were considered.
Methods: We formed NSHs by mixing appropriate amounts of lecithin, glycerol and supernatant of isolation of extracellular vesicles
from spruce needle homogenate. We visualized NSHs by light microscopy and cryogenic transmission electron microscopy and
assessed them by flow cytometry, dynamic light scattering, ultraviolet–visual spectroscopy, interferometric light microscopy and liquid
chromatography–mass spectrometry.
Results: We found that the particles consisted of a bilayer membrane and a fluid-like interior. Flow cytometry and
interferometric light microscopy measurements showed that the majority of the particles were nano-sized. Dynamic light
scattering and interferometric light microscopy measurements agreed well on the average hydrodynamic radius of the
particles Rh (between 140 and 180 nm), while the concentrations of the particles were in the range between 1013 and
1014/mL indicating that NSHs present a considerable (more than 25%) of the sample which is much more than the yield of
natural extracellular vesicles (EVs) from spruce needle homogenate (estimated less than 1%). Spruce specific lipids and
proteins were found in hybridosomes.
Discussion: Simple and low-cost preparation method, non-demanding saving process and efficient formation procedure suggest that
large-scale production of NSHs from lipids and spruce needle homogenate is feasible.
Plain Language Summary: Cells shed into their exterior nanoparticles (here referred to as extracellular vesicles – EVs) that
are free to move, reach distant cells and are taken up by them. As they carry bioactive constituents, EVs may have important
impact on the recipient cells. The mechanisms of EV formation and mediation can be employed in designing therapeutic,
prophylactic and diagnostic methods for various medical issues. EVs can be harvested from biological samples; however,
their yield is small,12 and there are potential side effects. Artificial vesicles – liposomes – have high yield; however, in vivo,
they can be degraded before reaching the target and their reproducibility is yet insufficient. In order to combine advantages of
both types of nanoparticles, we have composed nanohybridosomes (NSHs) from soya lecithin, water and supernatant of
isolation of EVs from spruce needle homogenate, visualized them by cryogenic electron microscopy and characterized them
with respect to their size, concentration and protein/nucleic acid content. We have applied a recently developed interferometric light microscopy to determine the hydrodynamic radius and the concentration of EVs. We found that the majority of
composed particles are nano-sized and that they enclose more than 25% of the incoming volume of liquid, which is considerably more than about 1% that can be harvested by isolation of EVs from spruce needle homogenate by (ultra)
centrifugatio
Assessment of small cellular particles from four different natural sources and liposomes by interferometric light microscopy
Small particles in natural sources are a subject of interest for their potential role in intercellular, inter-organism, and inter-species interactions, but their harvesting and assessment present a challenge due to their small size and transient identity. We applied a recently developed interferometric light microscopy (ILM) to assess the number density and hydrodynamic radius (Rh) of isolated small cellular particles (SCPs) from blood preparations (plasma and washed erythrocytes) (B), spruce needle homogenate (S), suspension of flagellae of microalgae Tetraselmis chuii (T), conditioned culture media of microalgae Phaeodactylum tricornutum (P), and liposomes (L). The aliquots were also assessed by flow cytometry (FCM), dynamic light scattering (DLS), ultraviolet-visible spectrometry (UV-vis), and imaging by cryogenic transmission electron microscopy (cryo-TEM). In Rh, ILM showed agreement with DLS within the measurement error in 10 out of 13 samples and was the only method used here that yielded particle density. Cryo-TEM revealed that representative SCPs from Tetraselmis chuii flagella (T) did not have a globular shape, so the interpretation by Rh of the batch methods was biased. Cryo-TEM showed the presence of thin filaments in isolates from Phaeodactylum tricornutum conditioned culture media (P), which provides an explanation for the considerably larger Rh obtained by batch methods than the sizes of particles observed by cryo-TEM images. ILM proved convenient for assessment of number density and Rh of SCPs in blood preparations (e.g., plasma)therefore, its use in population and clinical studies is indicated