Lipid Transition Research Articles

Enhancement of Galantamine HBr Skin Permeation Using Sonophoresis and Limonene-Containing PEGylated Liposomes.

This study aimed to investigate the effect of low-frequency sonophoresis (SN) and limonene-containing PEGylated liposomes (PL) on the transdermal delivery of galantamine HBr (GLT). To evaluate the skin penetration mechanism, confocal laser scanning microscopy (CLSM), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC) were employed. The application of SN led to more GLT penetration into and through the skin than GLT solution alone. The liposomes also improved GLT permeation, and 2% limonene-containing PL (PL-LI2%) exhibited the highest GLT permeation, followed by PL-LI1%, PL-LI0.1%, and PL. The CLSM images of PL-LI2% resulted in the highest fluorescence intensity of fluorescent hydrophilic molecules in the deep skin layer, and the rhodamine PE-labeled liposome membrane was distributed in the intercellular region of the stratum corneum (SC). PL-LI2% induced significant changes in intercellular lipids in the SC, whereas SN had no effect on intercellular lipids of the SC. DSC thermograms showed that the greatest decrease in the lipid transition temperature occurred in PL-LI2%-treated SC. SN might improve drug permeation through an intracellular pathway, while limonene-containing liposomes play an important role in delivering GLT through an intercellular pathway by increasing the fluidity of intercellular lipids in the SC. Moreover, a small vesicle size and high membrane fluidity might enhance the transportation of intact vesicles through the skin.

Intramolecular structural parameters are key modulators of the gel-liquid transition in coarse grained simulations of DPPC and DOPC lipid bilayers

The capability of coarse-grained models based on the MARTINI mapping to reproduce the gel-liquid phase transition in saturated and unsaturated model lipids was investigated. We found that the model is able to reproduce a lower critical temperature for 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) with respect to 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). Nonetheless, the appearance of a gel phase for DOPC is strictly dependent on the intramolecular parameters chosen to model its molecular structure. In particular, we show that the bending angle at the coarse-grained bead corresponding to the unsaturated carbon-carbon bond acts as an order parameter determining the temperature of the phase transition. Structural analysis of the molecular dynamics simulations runs evidences that in the gel phase, the packing of the lipophilic tails of DOPC assume a different conformation than in the liquid phase. In the latter phase, the DOPC geometry resembles that of the relaxed free molecule. DPPC:DOPC mixtures show a single phase transition temperature, indicating that the observation of a phase separation between the two lipids requires the simulation of systems with sizes much larger than the ones used here.

The impact of particle preparation methods and polymorphic stability of lipid excipients on protein distribution in microparticles

Objective: The present study aimed at elucidating the influence of polymorphic stability of lipid excipients on the physicochemical characters of different solid lipid microparticles (SLM), with the focus on the alteration of protein distribution in SLM.Methods: Labeled lysozyme was incorporated into SLM prepared with different excipients, i.e. trimyristin (TG14), glyceryl distearate (GDS), and glyceryl monostearate (GMS), by water-oil-water (w/o/w) or solid-oil-water (s/o/w) method. The distribution of lysozyme in SLM and the release of the protein from SLM were evaluated by confocal laser scanning microscopy. The storage stability of SLM was characterized by HPLC, differential scanning calorimetry, X-ray powder diffraction, and scanning electron microscopy.Results: Lysozyme was displayed as small scattered domains inside GDS and GMS SLM, whereas it was incorporated in the core of TG14 SLM formulated by the w/o/w method or evenly distributed in TG14 SLM prepared by the s/o/w method. Stability study at 37 °C revealed that only TG14 SLM made by the w/o/w method was able to maintain the lysozyme amount both on the particle surface and released from the SLM. Elevated storage temperature induced polymorphic transition of lipids in GDS and GMS SLM, which was, however, not remarkable for the TG14 SLM.Conclusions: Lipid excipients and particle preparation methods were found to differently affect the lysozyme distribution in SLM, owning to varied storage stabilities of the lipids. The present study provides updated knowledge for rational development of lipid-based formulations for oral delivery of peptide or protein drugs.

ATR-IR study of skin components: Lipids, proteins and water. Part I: Temperature effect

In this work we report the studies of the effect of temperature on skin components, such as lipids, proteins and water. Modifications of lipids structure induced by increasing temperature (from 20 to 90°C) have been studied using ATR-IR (Attenuated Total Reflectance Infrared) spectroscopy, which is a powerful tool for characterization of the molecular structure and properties of tissues, such as skin. Due to the small depth of penetration (0.6–5.6μm), ATR-IR spectroscopy probes only the outermost layer of the skin, i.e. the stratum corneum (SC). The assignment of main spectral features of skin components allows for the determination of phase transitions from the temperature dependencies of band intensities [e.g. νas(CH2) and νs(CH2)]. The phase transitions were determined by using two methods: the first one was based on the first derivative of the Boltzmann function and the second one employed tangent lines of sigmoidal, aforementioned dependencies. The phase transitions in lipids were correlated with modifications of the structure of water and proteins.

Enhanced Sampling of Phase Transitions in Coarse-Grained Lipid Bilayers.

Freezing and melting of dipalmitoylphosphatidylcholine (DPPC) bilayers are simulated in both the explicit (Wet) and implicit solvent (Dry) coarse-grained MARTINI force fields with enhanced sampling, via the isobaric, molecular dynamics version of the generalized replica exchange method (gREM). Phase transitions are described with the entropic viewpoint, based upon the statistical temperature as a function of enthalpy, TS(H) = 1/(dS(H)/dH), where S is the configurational entropy. Bilayer thickness, area per lipid, and the second-rank order parameter (P2) are calculated vs temperature in the transition range. In a 32-lipid Wet MARTINI system, transitions in the lipid and water subsystems are strongly coupled, giving rise to considerable structure in TS(H) and the need to specify the state of the water when reporting a lipid transition temperature. For gel lipid + liquid water → fluid lipid + liquid water, we find 292.4 K. The small system is influenced by finite-size effects, but it is argued that the entropic approach is well suited to revealing them, which will be particularly relevant for studies of finite nanosystems where there is no thermodynamic limit. In a 390-lipid Dry MARTINI system, two-dimensional analogues of the topographies of coexisting states ("subphases") seen in pure fluids are found. They are not seen in the 32-lipid Wet or Dry system, but the Dry lipids show a new type of state with gel in one leaflet and tilted gel in the other. Dry bilayer transition temperatures are 333.3 K (390 lipids) and 338 K (32 lipids), indicating that the 32-lipid system is not too small for a qualitative study of the transition. Physical arguments are given for Dry lipid system size dependence and for the difference between Wet and Dry systems.

Functionally significant low-temperature structural alterations in mitochondrial membranes of homoiothermic animals

This work is focused on the physicochemical nature and functional meaning of structural alterations in mitochondrial membranes. These alterations are observed at subnormal temperatures for homeothermic animals. Using pyrene as a fluorescent probe, some structural transitions in annular lipids were detected at 19 and 25°C, which are identified as the pre-transition and main phase transition temperatures. The observed changes are consistent with abrupt alterations in the efficiency of tryptophan fluorescence quenching by pyrene that occur at the same temperatures. The data imply considerable changes in the protein–lipid contact area. The effects are observed under low-amplitude mitochondrial swelling in media with lowered tonicity. Since the transition of the phosphorylating system into the supercomplex state has been previously shown under these conditions, it allows us to assume a relationship between the observed membrane structural alterations and the supercomplex formation. Measurements of the respiration rate in mitochondria in a hypoosmotic medium show that the activation energy of the rate-limiting step in the process of ATP synthesis changes abruptly at the temperature of the phase transition of annular lipids (25°C). Analysis of the literature data indicates that a similar abnormal low-temperature abrupt change in activation energy in the reaction of ATP synthesis around 25°C is observed for a variety of animal species. Hence, the low-temperature structural alterations in membranes of warm-blooded animals should have general biological importance. A comparison of the results obtained in our study and the literature data led, therefore, to a qualitative description of the physiochemical nature of the observed membrane alterations. Similar to the membrane-raft model, a model of supercomplex formation in mitochondria is proposed.

Structural Rearrangements in GABA

GABAA receptors (GABARs) are allosteric proteins that convert a chemical signal (GABA binding) to an electrical signal (opening of an integral ion-conducting channel). They mediate inhibition in the brain and are the therapeutic targets for a variety of drugs such as benzodiazepines (BZDs), barbiturates, neuroactive steroids, volatile and intravenous anesthetics. For these receptors, binding of neurotransmitter in the extracellular ligand-binding domain triggers opening of an intrinsic ion channel more than 50A away in the transmembrane domain of the receptor. While recent structures of prokaryotic and eukaryotic pLGICs solved in detergent micelles have shed light on their molecular architecture, a full understanding of pLGIC function requires knowledge of the protein motions that govern their conformational transitions in physiological lipids. Comparing closed versus open channel structures of prokaryotic and eukaryotic pLGICs predict that agonist-mediated channel opening is associated with a quaternary twisting and a radial un-blooming (inward tilting) of the extracellular binding domain (ECD). Using a luminescence resonance energy transfer (LRET) approach that allows us to measure structural motions in full length heteropentameric GABARs in live cells, we are examining if, and how, the ECD moves in response to agonist-dependent gating transitions and allosteric drug binding. We found that GABA decreased the distances between fluorescent probes attached to the ECD of both the alpha and beta GABAR subunits, whereas binding of a competitive antagonist had no effect consistent with receptor activation promoting a global inward tilting of the ECD. Surprisingly, a BZD positive modulator that binds in the ECD but does not open the ion channel induced similar decreases in LRET-based distances as GABA raising the intriguing idea that the inward motion may reflect a low affinity to high affinity binding site transition in the ECD versus a closed to open channel transition.

Line Tension Assists Membrane Permeation at the Transition Temperature in Mixed-Phase Lipid Bilayers.

The umbrella sampling method has been used to evaluate the free energy profile for a large permeant moving through a lipid bilayer, represented using a coarse-grained simulation model, at and below its gel-fluid transition temperature. At the lipid transition temperature, determined to be 302 K for the MARTINI 2.0 model of DPPC, the permeation barrier for passage through an enclosed fluid domain embedded in a patch of gel was significantly lower than that for passage through a fluid stripe domain. In contrast, permeation through a fluid domain in a stripe geometry produced a free energy profile nearly identical to that of a gel-free fluid bilayer. In both cases, insertion of the permeant into a fluid domain coexisting with the gel phase led to a shift in phase composition, as lipids transitioned from fluid to gel to accommodate the area occupied by the permeant. In the case of the enclosed fluid domain, this transition produced a decrease in the length of the fluid-gel interface as the approximately circular fluid domain shrank. The observed decrease in the apparent permeation barrier, combined with an approximation for the change in interfacial length, enabled estimation of the interfacial line tension to be between 10 and 13 pN for this model. The permeation barrier was shown to drop even further in simulations performed at temperatures below the transition temperature. The results suggest a mechanism to explain the experimentally observed anomalous peak in the temperature-dependent permeability of lipid bilayers near their transition temperatures. The contribution of this mechanism toward the permeability of a gel phase containing a thermal distribution of fluid-phase domains is estimated using a simple statistical thermodynamic model.

Lennard-Jones type pair-potential method for coarse-grained lipid bilayer membrane simulations in LAMMPS

Lipid bilayer membranes have been extensively studied by coarse-grained molecular dynamics simulations. Numerical efficiencies have been reported in the cases of aggressive coarse-graining, where several lipids are coarse-grained into a particle of size 4∼6nm so that there is only one particle in the thickness direction. Yuan et al. proposed a pair-potential between these one-particle-thick coarse-grained lipid particles to capture the mechanical properties of a lipid bilayer membrane, such as gel–fluid–gas phase transitions of lipids, diffusion, and bending rigidity Yuan et al. (2010). In this work we implement such an interaction potential in LAMMPS to simulate large-scale lipid systems such as a giant unilamellar vesicle (GUV) and red blood cells (RBCs). We also consider the effect of cytoskeleton on the lipid membrane dynamics as a model for RBC dynamics, and incorporate coarse-grained water molecules to account for hydrodynamic interactions. The interaction between the coarse-grained water molecules (explicit solvent molecules) is modeled as a Lennard-Jones (L-J) potential. To demonstrate that the proposed methods do capture the observed dynamics of vesicles and RBCs, we focus on two sets of LAMMPS simulations: 1. Vesicle shape transitions with enclosed volume; 2. RBC shape transitions with different enclosed volume. Finally utilizing the parallel computing capability in LAMMPS, we provide some timing results for parallel coarse-grained simulations to illustrate that it is possible to use LAMMPS to simulate large-scale realistic complex biological membranes for more than 1 ms. Program summaryProgram Title: fluidmembraneProgram Files doi:http://dx.doi.org/10.17632/4v53nkv5hc.1Licensing provisions: GNU GPLv3Programming language: C++.Nature of problem:A pair-potential function for simulating the shape transition of fluid vesicles and the resting shapes of red blood cells.Program Solution method:Nosé-Hoover thermostat and Berendsen pressure coupling algorithms.External routines/libraries: LAMMPSSubprograms used: create_rbc_with_water (MATLAB), bond_harmonic1 (C++), in_example (LAMMPS input script).

The temperature-dependent physical state of polar lipids and their miscibility impact the topography and mechanical properties of bilayer models of the milk fat globule membrane

The polar lipid assembly and biophysical properties of the biological membrane enveloping the milk fat globules (the MFGM) are yet poorly known, especially in connection with the temperature history that milk can experience after its secretion. However, bioactive mechanisms depend on biological structure, which itself highly depend on temperature. The objectives of this study were to investigate polar lipid packing in hydrated bilayers, models of the MFGM, and to follow at intermolecular level temperature-induced changes in the range 60–6°C, using the combination of differential scanning calorimetry, X-ray diffraction, atomic force microscopy (AFM) imaging and force spectroscopy. MFGM polar lipids, especially sphingomyelin, contain long chain saturated fatty acids with high phase transition temperatures. On cooling, the liquid disordered ld to solid ordered so (gel) phase transition of MFGM polar lipids started at about 40°C, leading to phase separation and formation of so phase domains protruding by about 1nm from the ld phase. Indentation measurements using AFM revealed that the resistance of the so phase domains to rupture was significantly higher than that of the ld phase and that it increased for both the domain and fluid phases with decreasing temperature. However, packing and stability of the bilayers were adversely affected by fast cooling to 6°C or by cooling-rewarming cycle. This study showed that MFGM polar lipid bilayers are dynamic systems. Heterogeneity in the structure and mechanical properties of the membrane was induced by temperature-dependent so/ld phase immiscibility of the lipid components. This could have consequences on the MFGM technological and biological functions (e.g. immunity and milk lipid digestion).

Revealing the mechanism of passive transport in lipid bilayers via phonon-mediated nanometre-scale density fluctuations.

The passive transport of molecules through a cell membrane relies on thermal motions of the lipids. However, the nature of transmembrane transport and the precise mechanism remain elusive and call for a comprehensive study of phonon excitations. Here we report a high resolution inelastic X-ray scattering study of the in-plane phonon excitations in 1,2-dipalmitoyl-sn-glycero-3-phosphocholine above and below the main transition temperature. In the gel phase, for the first time, we observe low-frequency transverse modes, which exhibit a phonon gap when the lipid transitions into the fluid phase. We argue that the phonon gap signifies the formation of short-lived nanometre-scale lipid clusters and transient pores, which facilitate the passive molecular transport across the bilayer plane. Our findings suggest that the phononic motion of the hydrocarbon tails provides an effective mechanism of passive transport, and illustrate the importance of the collective dynamics of biomembranes.

High Pressure Processing Effects on Lipids Thermophysical Properties and Crystallization Kinetics

This review examines the combined pressure–thermal effects on thermophysical and crystallization properties of lipids. Pressure treatment transiently accelerates the phase transition and shifts the melting temperature of lipids by 10 °C/100 MPa–20 °C/100 MPa. It also transiently alters various thermophysical properties of lipids including density, viscosity, thermal conductivity, and specific heat. The interdependence phase transition of lipids with their corresponding thermophysical properties is highlighted. The magnitude and rate of pressure application influences the mechanism of lipid crystallization under pressure. For example, slow multi-step modest pressure buildup (100–200 MPa) promotes heterogeneous nucleation and slow crystallization which result in stable crystal structures. Increasing the magnitude of pressure by 400–500 MPa accelerates the nucleation rate significantly. On the other hand, rapid single-step pressurization, regardless of pressure level, induces instantaneous volumetric crystallization of less stable crystal structure which is subsequently modified into stable crystal polymorphs during depressurization. High pressure crystallization is also influenced by temperature, pressure holding time, compression rate, compression cycle, and lipid compositions. The effects of pressure treatment are more pronounced in saturated fatty acids compared to unsaturated ones, and it is shown that triglycerides crystallize more slowly under pressure than free fatty acids.

Lessons learned in andrology: looking at the spermatozoa in context.

Lessons learned in andrology: looking at the spermatozoa in context.

Development of protective protein emulsion technology for mechanically deboned poultry meat

Using mechanically deboned poultry meat (MPMO) to sell as mincemeat or recipe ingredient has a number of negative aspects that lie in the oxidation and microbiological stability reduction, caused by production factors and biochemical properties of such raw product as a result of the transition of bone marrow lipids and hemoproteins. On this basis, the paper is aimed at using protective protein emulsions (PPE) that contain mostly natural components and allow to some extent eliminate the negative impact of phospholipid compounds, heme pigments and so on. The results of the design and scientific substantiation of technological solutions that allow to increase the functional and technological and improve consumer properties of mechanically deboned poultry meat (chicken) by adding the PPE, protein preparation from pork skin ScangelA95, sodium ascorbyl palmitate antioxidant are given in the paper. It was found that introducing the proposed PPE leads to increased shear stress limit, reduced intensity of a specific dirty red color of MDPM towards pale red and pink, approximating color to characteristic for minced chicken from shin muscles, loss of gloss and matte appearance, improved mincemeat stability, which lies in reduced oxidation product formation intensity.

Combined force spectroscopy, AFM and calorimetric studies to reveal the nanostructural organization of biomimetic membranes

In this work we studied a binary lipid matrix of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1′-rac-glycerol) (POPG), a composition that mimics the inner membrane of Escherichia coli. More specifically, liposomes with varying fractions of POPG were analysed by differential scanning calorimetry (DSC) and a binary phase diagram of the system was created. Additionally, we performed atomic force microscopy (AFM) imaging of supported lipid bilayers (SLBs) of similar compositions at different temperatures, in order to create a pseudo-binary phase diagram specific to this membrane model. AFM study of SLBs is of particular interest, as it is conceived as the most adequate technique not only for studying lipid bilayer systems but also for imaging and even nanomanipulating inserted membrane proteins. The construction of the above-mentioned phase diagram enabled us to grasp better the thermodynamics of the thermal lipid transition from a gel-like POPE:POPG phase system to a more fluid phase system. Finally, AFM force spectroscopy (FS) was used to determine the nanomechanics of these two lipid phases at 27°C and at different POPG fractions. The resulting data correlated with the specific composition of each phase was calculated from the AFM phase diagram obtained. All the experiments were done in the presence of 10mM of Ca2+, as this ion is commonly used when performing AFM with negatively charged phospholipids.

Generation‐Dependent Gel–Fluid Phase Transition of Membrane Caused by a PAMAM Dendrimer

Coarse‐grained molecular dynamics simulations are performed to investigate the effects of dendrimer size and lipid phase on the dendrimer–membrane interactions. It is found that the low‐generation dendrimer flattens on the gel‐phase bilayer without any disturbance of lipids, while dendrimers with immediate generation can fluidize the upper leaflet of the membrane. High‐generation dendrimers can induce the gel–fluid phase transition of lipids in the vicinity of the dendrimer and the significant bending of membranes. The phase transition is companied by membrane thinning and facilitates a domain formation on the membrane. The findings suggest that high‐generation dendrimers are much more effective in disturbing membranes not only at high temperature but also at low temperature. This work is helpful to understand the binding and internalization mechanisms of cationic nanoparticles into cells involving lipid rafts and endocytosis.

Lipid diffusion in alcoholic environment.

We have studied the effects of a high concentration of butanol and octanol on the phase behavior and on the lateral mobility of 1,2-palmitoyl-sn-glycero-3-phosphocholine (DPPC) by means of differential scanning calorimetry and pulsed-gradient stimulated-echo (PGSTE) NMR spectroscopy. A lowering of the lipid transition from the gel to the liquid-crystalline state for the membrane-alcohol systems has been observed. NMR measurements reveal three distinct diffusions in the DPPC-alcohol systems, characterized by a high, intermediate, and slow diffusivity, ascribed to the water, the alcohol, and the lipid, respectively. The lipid diffusion process is promoted in the liquid phase while it is hindered in the interdigitated phase due to the presence of alcohols. Furthermore, in the interdigitated phase, lipid lateral diffusion coefficients show a slight temperature dependence. To the best of our knowledge, this is the first time that lateral diffusion coefficients on alcohol with so a long chain, and at low temperatures, are reported. By the Arrhenius plots of the temperature dependence of the diffusion coefficients, we have evaluated the apparent activation energy in both the liquid and in the interdigitated phase. The presence of alcohol increases this value in both phases. An explanation in terms of a free volume model that takes into account also for energy factors is proposed.

TNF-α and Th2 Cytokines Induce Atopic Dermatitis–Like Features on Epidermal Differentiation Proteins and Stratum Corneum Lipids in Human Skin Equivalents

Atopic dermatitis (AD) is a chronic inflammatory skin disease in which the skin barrier function is disrupted. In this inflammatory AD environment, cytokines are upregulated, but the cytokine effect on the AD skin barrier is not fully understood. We aimed to investigate the influence of Th2 (IL-4, IL-13, IL-31) and pro-inflammatory (tumor necrosis factor alpha (TNF-α)) cytokines on epidermal morphogenesis, proliferation, differentiation, and stratum corneum lipid properties. For this purpose, we used the Leiden epidermal model (LEM) in which the medium was supplemented with these cytokines. Our results show that IL-4, IL-13, IL-31, and TNF-α induce spongiosis, augment TSLP secretion by keratinocytes, and alter early and terminal differentiation-protein expression in LEMs. TNF-α alone or in combination with Th2 cytokines decreases the level of long chain free fatty acids (FFAs) and ester linked ω-hydroxy (EO) ceramides, consequently affecting the lipid organization. IL-31 increases long chain FFAs in LEMs but decreases relative abundance of EO ceramides. These findings clearly show that supplementation with TNF-α and Th2 cytokines influence epidermal morphogenesis and barrier function. As a result, these LEMs show similar characteristics as found in AD skin and can be used as an excellent tool for screening formulations and drugs for the treatment of AD.

Manipulating nanoscale features on the surface of dye-loaded microbubbles to increase their ultrasound-modulated fluorescence output.

The nanoscale surface features of lipid-coated microbubbles can dramatically affect how the lipids interact with one another as the microbubble diameter expands and contracts under the influence of ultrasound. During microbubble manufacturing, the different lipid shell species naturally partition forming concentrated lipid islands. In this study the dynamics of how these nanoscale islands accommodate the expansion of the microbubbles are monitored by measuring the fluorescence intensity changes that occur as self-quenching lipophilic dye molecules embedded in the lipid layer change their distance from one another. It was found that when the dye molecules were concentrated in islands, less than 5% of the microbubbles displayed measurable fluorescence intensity modulation indicating the islands were not able to expand sufficiently for the dye molecules to separate from one another. When the microbubbles were heated and cooled rapidly through the lipid transition temperature the islands were melted creating an even distribution of dye about the surface. This resulted in over 50% of the microbubbles displaying the fluorescence-modulated signal indicating that the dye molecules could now separate sufficiently to change their self-quenching efficiency. The separation of the surface lipids in these different formations has significant implications for microbubble development as ultrasound and optical contrast agents.

Hydration and Temperature-Induced Phospholipid Phase Transitions and their Influence on Desiccation Tolerance of the Nematode Caenorhabditis Elegans

The nematode Caenorhabditis elegans can bypass part of its normal larval development by forming a state with arrested metabolism. The desiccation-tolerance of this state depends on the synthesis of trehalose during a preconditioning phase, where the worm is first exposed to mildly reduced RH, rendering the dauer state attractive for studying the physiology and genetics of Anhydrobiosis. Here, we correlate physical properties of phospholipids (PLs) with the desiccation tolerance of the larvae from which PLs were extracted. The response of PL structure to transient (seconds) changes in water potential and the role of trehalose in water-mediated structural transitions were addressed. Time-resolved Rapid scan FTIR spectroscopy was used in ATR geometry to record hydration-induced difference spectra. We show by chemical analysis that a reduction in choline content in the PL headgroup composition arises during preconditioning. This leads to a stronger coupling of headgroup hydration to disorder in PL acyl chains based on the time-resolved observation of PO2-, C=O and acyl CH2 stretching modes. Trehalose enhances this effect and leads to more uniform kinetics of hydration transients and lipid transitions. In combination with spectroscopic determination of altered lipid main phase transition temperatures (Tm) in PLs upon preconditioning, the data show that chemical tuning of the kinetics and the extent of coupling of headgroup hydration to acyl chain packing changes is a key process in desiccation tolerance as it may release mechanical stress from membranes during temporal changes of water potential. Additional DSC, ITC and Langmuir-Blodget data show that trehalose interacts more favourably with PLs from preconditioned larvae to support desiccation tolerance. This work highlights that chemical tuning of lyotropic phase transitions plays a fundamental role in the trehalose-dependent desiccation tolerance of C. elegans larvae.