bioRxiv Science⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/859124

Biophysical characterization reveals the similarities of liposomes produced using microfluidics and electroformation

Schaich, M.·Sobota, D.·Sleath, H.·Cama, J.·Keyser, U. F.
View original source ↗Export metadata ↓

Abstract

Giant Unilamellar Vesicles (GUVs) are a versatile tool in many branches of science, including biophysics and synthetic biology. Octanol-Assisted Liposome Assembly (OLA), a recently developed microfluidic technique enables the production and testing of GUVs within a single device under highly controlled experimental conditions. It is therefore gaining significant interest as a platform for use in drug discovery, the production of artificial cells and more generally for controlled studies of the properties of lipid membranes. In this work, we expand the capabilities of the OLA technique by forming GUVs of tunable binary lipid mixtures of DOPC, DOPG and DOPE. Using fluorescence recovery after photobleaching we investigated the lateral diffusion coefficients of lipids in OLA liposomes and found the expected values in the range of 1 m2/s for the lipid systems tested. We studied the OLA derived GUVs under a range of conditions and compared the results with electroformed vesicles. Overall, we found the lateral diffusion coefficients of lipids in vesicles obtained with OLA to be quantitatively similar to those in vesicles obtained via traditional electroformation. Our results provide a quantitative biophysical validation of the quality of OLA derived GUVs, which will facilitate the wider use of this versatile platform.

Source connections

Explore related subjects

biophysicsPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Schaich, M., Sobota, D., Sleath, H., Cama, J., Keyser, U. F.. 2019-11-28. Biophysical characterization reveals the similarities of liposomes produced using microfluidics and electroformation. https://doi.org/10.1101/859124

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Semidilute Polymer Scaling Controls PEG-induced Protein Phase Separation

When does polyethylene glycol (PEG) mass concentration provide a common measure of crowding strength across polymer chain lengths? Here we use bovine serum albumin (BSA) and PEG as a controlled depletion system and measure both coexisting phases to determine binodals, tie lines, and critical points across PEG molecular weights of 4--100 kDa. Phase diagrams for PEG 20, 35, and 100 kDa approximately collapse in mass-concentration coordinates, consistent with semidilute polymer scaling. Generalized free volume theory (GFVT) describes the BSA binodals and tie lines. It also approximately describes binodals for three additional globular proteins in PEG 35K, extending the comparison across proteins spanning 7.2--66.4 kDa. For the binary PEG mixtures tested, GFVT approximates the binodals using an effective polymer size corresponding to the weight-average molecular weight. These results identify a regime in which PEG mass concentration (g/L) provides a transferable measure of depletion-induced crowding.

biophysics↗
bioRxiv2026

Correlation-resolved sum-frequency generation microscopy of biological tissue with bright twin beams

Sum-frequency generation (SFG) driven by bright twin beams generated through high-gain parametric down-conversion comprises a coherent component arising from correlated mode pairs and an incoherent component arising from interactions between uncorrelated modes. Modal correlations can enhance coherent SFG in anisotropic nonlinear media, for example by extending the effective interaction length. Whether such correlations can likewise benefit image formation in heterogeneous biological tissue remains unknown. Here we address this question by performing SFG imaging of biological tissue using bright twin beams as the excitation source. Spectral decomposition of the SFG signal separates its coherent and incoherent components, allowing us to reconstruct co-registered images and examine how twin-beam correlations influence image formation. In mouse skeletal muscle, the coherent-component image revealed sarcomere periodicity with a Bragg-spot-to-background ratio of approximately 310, compared with 7.5 in the incoherent-component image. In fresh human dermis, the coherent-component image showed greater Fourier power than the incoherent-component image in the 0.30-0.50 \mu m^{-1} band and a greater fractional autocovariance decay at short spatial lags. These results demonstrate that twin-beam correlations can enhance contrast and detectability at selected spatial frequencies in heterogeneous tissue. Correlation-resolved SFG microscopy thus offers a route for exploiting bright quantum-light sources in nonlinear optical bioimaging.

biophysics↗
bioRxiv2026

Polarization affects viscoelasticity and podosome distribution of primary human macrophages

Macrophages are essential cells of the innate immune system that regulate wound healing and tissue homeostasis. They exert diverse functions, depending on their polarization state, which can lead to either functional healing of the tissue or fibrosis. Macrophage polarization state is affected by both the local biochemical and mechanical microenvironment within the tissue, suggesting a possible dependence of macrophage function on cell mechanical state, which has been poorly explored to date. In this study, we provide a systematic and quantitative characterization of the viscoelastic properties of unstimulated, pro-inflammatory, and anti-inflammatory monocyte-derived primary human macrophages at the single-cell level using atomic force microscopy. Pro-inflammatory macrophages exhibited a lower elastic modulus (E = 458.8 {+/-} 179.9 Pa) and a more dissipative response (low frequency exponent = 0.22 {+/-} 0.03) than anti-inflammatory macrophages (E = 716 {+/-} 345.6 Pa and = 0.15 {+/-} 0.04). These differences in mechanical properties were independent of cell morphology but correlated with differences in podosome distribution with pro-inflammatory macrophages exhibiting a dispersed distribution, and anti-inflammatory macrophages a more clustered distribution. This study identifies polarization-dependent mechanical differences in human primary macrophages and provides a quantitative experimental framework for future work in macrophage mechanobiology.

biophysics↗