Propofol (2,6-bis(1-methylethyl)phenol) is a small lipophilic neuroactive drug used extensively in anesthesia. While its mechanism of action is known, its temporary effects on the lipid composition of cell membranes have not been fully elucidated. A structurally related series of saturated phospholipids with C14-acyl chains and different polar head groups is utilized in the present study with a view to understanding specific drug–lipid interactions in model membranes at the air–water interface. Langmuir surface pressure–area isotherms show that propofol can shift the lipid phase transitions to higher areas per lipid molecule and surface pressures. Brewster angle microscopy imaging shows that the drug exhibits a fluidizing effect on the lipid morphology, resulting in the formation of bright circular domains with reduced line tension. Neutron reflectometry reveals effects of squeezing out of the drug from the membranes during membrane compression, as the location and amount of the drug are quantified for these systems for the first time. The greatest overall drug−lipid interactions are with the phosphatidylcholine lipid, where the drug is located predominantly in the relatively fluid acyl chains. The greatest drug−lipid head group interactions are with the phosphatidylethanolamine lipid, which is discussed as an interplay between its squeezing out from the acyl chains due to their more condensed nature and possible specific interactions between the hydroxyl group on the drug and the ammonium group on the lipid head group. An absence of drug interactions was observed with the charged head group of the phosphatidylglycerol lipid. It is concluded that changes in membrane fluidity caused by different lipid polar head groups modulate the extent and nature of the drug–membrane interactions more generally than specific intermolecular interactions between chemical groups or effects of lipid head group charge. These new findings provide a fresh perspective on the processes influencing lipid interactions of a small hydrophobic drug and its distribution within lipid membranes, understanding which links to reducing side effects in patients from medication-induced changes to cell membrane composition

The continuous quest for materials capable of providing sustained release of antimicrobial drugs is particularly important for indwelling medical applications. In this study, we utilized amoxicillin as a model active pharmaceutical ingredient (API) to investigate the feasibility of using porous media – specifically, functionalized calcium carbonate (FCC) microparticles – as a primary drug carrier embedded within an ethyl cellulose (EC) polymer film. Our main objective was to prolong and sustain the release of the API. The fabrication process of the microparticle containing film involved two key steps: loading the model API into the FCC particles and then embedding these loaded particles into the polymeric film. Amoxicillin was loaded into the FCC particles using a solvent evaporation method. Detailed characterization through Scanning Electron Microscopy (SEM), lab- and synchrotron-based XRD revealed that amoxicillin precipitated both inside and on the surface of the FCC particles, predominantly in an amorphous form. Additionally, ultraviolet-visible (UV-vis) spectroscopic data demonstrated an increased release rate from the porous FCC compared to direct dissolution of pure amoxicillin powder. Embedding amoxicillin preloaded porous FCC particles in the EC film led to a more rational sustained release compared with powder amoxicillin embedded directly in the film, advantageously delivering the same amount of amoxicillin over a longer period; a result that may be relevant for indwelling medical devices such as urinary catheters, vascular access devices or wound drains

A synchrotron-based experiment was carried out to demonstrate the potential of x-ray photon correlation spectroscopy (XPCS) to characterize collective dynamics driven by superparamagnetic iron oxide nanoparticles (SPIONs) during magnetomotive ultrasound (MMUS) imaging. MMUS is a developing diagnostic imaging technique that has the potential to enable more precise cancer staging than other clinically established diagnostic tools. It relies on SPIONs acting as a contrast agent while being stimulated by time-varying magnetic fields. The resulting dynamics are crucial to maximizing image contrast. We describe the design and execution of an XPCS experiment on phantoms mimicking human tissue during MMUS imaging. Quantitative analysis of the results reveals variations in the temporal correlation functions of the scattered intensity as a function of scattering vector and angle. Preliminary observations indicate that these variations might depend on experimental parameters such as the frequency and strength of the magnetic field and SPION type and concentration

The coming years are expected to bring rapid changes in the nanotechnology regulatory landscape, with the establishment of a new framework for nano-risk governance, in silico approaches for characterisation and risk assessment of nanomaterials, and novel procedures for the early identification and management of nanomaterial risks. In this context, Safe(r)-by-Design (SbD) emerges as a powerful preventive approach to support the development of safe and sustainable (SSbD) nanotechnology-based products and processes throughout the life cycle. This paper summarises the work undertaken to develop a blueprint for the deployment and operation of a permanent European Centre of collaborating laboratories and research organisations supporting safe innovation in nanotechnologies. The proposed entity, referred to as “the Centre”, will establish a ‘one-stop shop’ for nanosafety-related services and a central contact point for addressing stakeholder questions about nanosafety. Its operation will rely on significant business, legal and market knowledge, as well as other tools developed and acquired through the EU-funded EC4SafeNano project and subsequent ongoing activities. The proposed blueprint adopts a demand-driven service update scheme to allow the necessary vigilance and flexibility to identify opportunities and adjust its activities and services in the rapidly evolving regulatory and nano risk governance landscape. The proposed Centre will play a major role as a conduit to transfer scientific knowledge between the research and commercial laboratories or consultants able to provide high quality nanosafety services, and the end-users of such services (e.g., industry, SMEs, consultancy firms, and regulatory authorities). The Centre will harmonise service provision, and bring novel risk assessment and management approaches, e.g. in silico methodologies, closer to practice, notably through SbD/SSbD, and decisively support safe and sustainable innovation of industrial production in the nanotechnology industry according to the European Chemicals Strategy for Sustainability.

Propofol is an amphiphilic small molecule that strongly influences the function of cell membranes, yet data regarding interfacial properties of propofol remain scarce. Here we consider propofol adsorption at the air/water interface as elucidated by means of vibrational sum frequency spectroscopy (VSFS), neutron reflectometry (NR), and surface tensiometry. VSFS data show that propofol adsorbed at the air/water interface interacts with water strongly in terms of hydrogen bonding and weakly in the proximity of the hydrocarbon parts of the molecule. In the concentration range studied there is almost no change in the orientation adopted at the interface. Data from NR show that propofol forms a dense monolayer with a thickness of 8.4 Å and a limiting area per molecule of 40 Å2, close to the value extracted from surface tensiometry. The possibility that islands or multilayers of propofol form at the air/water interface is therefore excluded as long as the solubility limit is not exceeded. Additionally, measurements of the 1H NMR chemical shifts demonstrate that propofol does not form dimers or multimers in bulk water up to the solubility limit.

phospholipid, NR data reveal that propofol is located exclusively in the head group region, which is rationalized in the context of previous studies. The results imply a non-homogeneous distribution of propofol in the plane of real cell membranes, which is an inference that requires urgent testing and may help to explain why such low concentration of the drug are required to induce general anaesthesia.

We investigate theoretically and experimentally the spontaneous imbibition of water based inkjet formulations utilizing paper capillary rise and imbibition of inkjet drops. We approximate the paper structure to a two dimensional anisotropic porous material, and using Darcy's law as a base, we derive dimensionless groups that scale drop imbibition. This derivation is based on a previous dimensional scaling of drop imbibition on thick isotropic porous material. We apply this scaling to a paper substrate by measuring the average drop imbibition rate, and perform paper capillary rise experiments to obtain the average system parameters required for the scaling. The results suggest that this approach is a valuable tool to predict drop imbibition rates on paper. We then continue and perform the same sets of experiments on a different paper with similar structure that is surface treated (surface sized) with CaCl2 salt, an additive that is known to improve print quality. We find that due to rapid aggregation of the colorant ink by the CaCl2, the imbibition rate is slowed down in the capillary rise experiments, i.e., on much larger scales compared to a single inkjet drop. However, the presence of CaCl2 has only minor effect over the average imbibition rates of single drops. Imbibition rates on the CaCl2 surface sized paper did not give adequate scaling as a result of the fact that the aggregation was not included the theoretical assumptions behind the scaling.