Nicholas Jan Brooks

The versatility of nanoscale lipid particles has positioned them as the scaffold of choice for biomedical delivery, synthetic membrane engineering, and fundamental biophysical exploration. Across these fields, rational particle design has become a major bottleneck. Lipid composition, stoichiometry, size, morphology, phase behavior, and biophysical properties combine into an enormous, high‑dimensional space that is inherently difficult to explore, making conventional optimization approaches slow and limited. Identifying optimal lipid compositions in this vast space necessitates high‐throughput screening based on efficient low‐cost automation. Here we introduce a high‐throughput microfluidic platform for rapid screening of lipid nanoparticles, offering precise, programmable control over composition and morphology. The system integrates on‐chip microfluidic metering of lipid stocks with continuous particle self‐assembly, followed by robotic collection into 96‐well plates. This workflow enables the generation of over 200 unique formulations per hour, delivering a several‐orders‐of‐magnitude increase in throughput relative to conventional approaches. We apply the platform to systematically map biophysical space at unprecedented resolution, validate compositional trends in transfection efficiency, and identify non‐lamellar formulations with optimal functional performance. By coupling scalable synthesis with automated screening, we expect this platform to provide a robust foundation for data‐driven and AI‐integrated discovery of self‐assembled nanomaterials including lipid, polymeric, and biomolecular assemblies.

Nile Red is an efficient tool to visualise the dissolution and propagation of agrochemicals within plant wax. A bright increase in intensity originates from the alleviation of emission quenching by wax components.

Certain fatty acid isomers have been linked to the development of several pathological conditions. For example, while oleic acid – a monounsaturated, cis fatty acid – is considered part of a healthy diet, its trans analogue elaidic acid is associated with an increased risk of developing cardiovascular diseases. Fatty acids can insert into cellular lipid membranes, changing their structural and biophysical features, and these alterations are believed to underpin some of the biomedical effects of these molecules. In this work, we unveil the effect of oleic and elaidic acid on the structure, lateral organization, and microviscosity of model membranes by using a combination of X-ray scattering and viscosity-sensitive dyes (‘molecular rotors’). Our results suggest that the cis isomer, oleic acid, is a more effective lineactant and minimizes the height mismatch between different lipid phases while maintaining the membrane’s lateral heterogeneity. We demonstrate that, as a consequence, the presence of oleic acid successfully dampens changes in membrane microviscosity under tension.

The actin cytoskeleton and its elaborate interplay with the plasma membrane participate in and control numerous biological processes in eukaryotic cells. Malfunction of actin networks and changes in their dynamics are related to various diseases, from actin myopathies to uncontrolled cell growth and tumorigenesis. Importantly, the biophysical and mechanical properties of actin and its assemblies are deeply intertwined with the biological functions of the cytoskeleton. Novel tools to study actin and its associated biophysical features are, therefore, of prime importance. Here we develop a new approach which exploits fluorescence lifetime imaging microscopy (FLIM) and environmentally sensitive fluorophores termed molecular rotors, acting as quantitative microviscosity sensors, to monitor dynamic viscoelastic properties of both actin structures and lipid membranes. In order to reproduce a minimal actin cortex in synthetic cell models, we encapsulated and attached actin networks to the lipid bilayer of giant unilamellar vesicles (GUVs). Using a cyanine-based molecular rotor, DiSC₂(3), we show that different types of actin bundles are characterized by distinct packing, which can be spatially resolved using FLIM. Similarly, we show that a lipid bilayer-localized molecular rotor can monitor the effects of attaching cross-linked actin networks to the lipid membrane, revealing an increase in membrane viscosity upon actin attachment. Our approach bypasses constraints associated with existing methods for actin imaging, many of which lack the capability for direct visualization of biophysical properties. It can therefore contribute to a deeper understanding of the role that actin plays in fundamental biological processes and help elucidate the underlying biophysics of actin-related diseases.

Lipid membranes are crucial for cellular integrity and regulation, and tight control of their structural and mechanical properties is vital to ensure that they function properly. Fluorescent probes sensitive to the membrane's microenvironment are useful for investigating lipid membrane properties; however, there is currently a lack of quantitative correlation between the exact parameters of lipid organization and a readout from these dyes. Here, we investigate this relationship for "molecular rotors", or microviscosity sensors, by simultaneously measuring their fluorescence lifetime to determine the membrane viscosity, while using X-ray diffraction to determine the membrane's structural properties. Our results reveal a phase-dependent correlation between the membrane's structural parameters and mechanical properties measured by a BODIPY-based molecular rotor, giving excellent predictive power for the structural descriptors of the lipid bilayer. We also demonstrate that differences in membrane thickness between different lipid phases are not a prerequisite for the formation of lipid microdomains and that this requirement can be disrupted by the presence of line-active molecules. Our results underpin the use of membrane-sensitive dyes as reporters of the structure of lipid membranes.

Lipid membranes are crucial for cellular integrity and regulation, and tight control of their structural and mechanical properties is vital to ensure that they function properly. Fluorescent probes sensitive to the mem-brane’s microenvironment are useful for investigating lipid membrane properties, however, there is currently a lack of quantitative correlation between the exact parameters of lipid organization and a readout from these dyes. Here, we investigate this relationship for ‘molecular rotors’, or microviscosity sensors, by simultaneously measuring their fluorescence lifetime to determine the membrane viscosity, while using the X-Ray diffraction the determine the membrane’s structural properties. Our results reveal a phase-dependent correlation be-tween the membrane’s structural parameters and mechanical properties measured by a BODIPY-based mo-lecular rotor, giving excellent predictive power for the structural descriptors of the lipid bilayer. We also demonstrate that differences in membrane thickness between different lipid phases is not a prerequisite for formation of lipid microdomains and that this requirement can be disrupted by the presence of line-active molecules. Our results underpin the use of membrane-sensitive dyes as reporters of the structure of lipid membranes.

Lipid peroxidation is a process which is key in cell signaling and disease, it is exploited in cancer therapy in the form of photodynamic therapy. The appearance of hydrophilic moieties within the bilayer’s hydrocarbon core will dramatically alter the structure and mechanical behavior of membranes. Here, we combine viscosity sensitive fluorophores, advanced microscopy, and X-ray diffraction and molecular simulations to directly and quantitatively measure the bilayer’s structural and viscoelastic properties, and correlate these with atomistic molecular modelling. Our results indicate an increase in microviscosity and a decrease in the bending rigidity upon peroxidation of the membranes, contrary to the trend observed with non-oxidized lipids. Fluorescence lifetime imaging microscopy and MD simulations give evidence for the presence of membrane regions of different local order in the oxidized membranes. We hypothesize that oxidation promotes stronger lipid-lipid interactions, which lead to an increase in the lateral heterogeneity within the bilayer and the creation of lipid clusters of higher order.

The modification of archaeal lipid bilayer properties by the insertion of apolar molecules in the lipid bilayer midplane has been proposed to support cell membrane adaptation to extreme environmental conditions of temperature and hydrostatic pressure. In this work, we characterize the insertion effects of the apolar polyisoprenoid squalane on the permeability and fluidity of archaeal model membrane bilayers, composed of lipid analogues. We have monitored large molecule and proton permeability and Laurdan generalized polarization from lipid vesicles as a function of temperature and hydrostatic pressure. Even at low concentration, squalane (1 mol%) is able to enhance solute permeation by increasing membrane fluidity, but at the same time, to decrease proton permeability of the lipid bilayer. The squalane physicochemical impact on membrane properties are congruent with a possible role of apolar intercalants on the adaptation of Archaea to extreme conditions. In addition, such intercalant might be used to cheaply create or modify chemically resistant liposomes (archeaosomes) for drug delivery.

Mixtures of fatty acids and phospholipids can form hexagonal (H_II) and inverse bicontinuous cubic phases, the latter of which are implicated in various cellular processes and have wide-ranging biotechnological applications in protein crystallisation and drug delivery systems. Therefore, it is vitally important to understand the formation conditions of inverse bicontinuous cubic phases and how their properties can be tuned. We have used differential scanning calorimetry and synchrotron-based small angle and wide angle X-ray scattering (SAXS/WAXS) to investigate the polymorphic phase behaviour of palmitic acid/partially-methylated phospholipid mixtures, and how headgroup methylation impacts on inverse bicontinuous cubic phase formation. We find that upon partial methylation of the phospholipid headgroup (1 or 2 methyl substituents) inverse bicontinuous cubic phases are formed (of the Im3m spacegroup), which is not the case with 0 or 3 methyl substituents. This shows how important headgroup methylation is for controlling phase behaviour and how a change in headgroup methylation can be used to controllably tune various inverse bicontinuous phase features such as their lattice parameter and the temperature range of their stability.