Langmuir

Cholesterol is a key component of cellular membranes, regulating membrane organization, fluidity, and signaling. However, cholesterol analysis remains technically challenging, as no single method currently allows both accurate quantification and spatially resolved visualization. Biochemical assays provide accurate quantification but lack spatial resolution, whereas imaging strategies can perturb membrane organization or cholesterol accessibility. Here, we describe optimized protocols using fluorescent D4 probes derived from the cholesterol-binding domain of perfringolysin O (D4-mCherry and D4-GFP) to detect, visualize, and quantify cholesterol in biological samples. We detail procedures for probe production, purification, and application, and establish conditions that ensure robust and reproducible labeling of membrane-accessible cholesterol. By combining fluorescence-based imaging with quantitative analysis, this approach enables the assessment of cholesterol distribution while preserving its native membrane environment. The proposed methodology provides a versatile and reliable framework for studying cholesterol in a wide range of experimental systems.

The apparent pKa of ionizable lipids in lipid nanoparticles (LNPs) is a key determinant of RNA encapsulation during formulation and endosomal release after cellular uptake. However, it is difficult to predict the effective pKa of a given ionizable lipid solely from its solution pKa, because it is sensitive to the membranes composition, as well as solution conditions such as the salt concentration. We developed a simple continuum electrostatics model, based on Gouy-Chapman theory, to predict the shift in effective pKa for ionizable lipids in lipid bilayers as a function of salt concentration and membrane composition. We derive equations for the surface potential and fraction of lipids charged, which are solved self-consistently as a function of solution pH to extract the titration curve and effective pKa. The model shows that the shift in effective pKa is largest when the concentration of titratable lipid is high, and the effect is diminished by increasing salt concentration. We provide a python implementation of the model and an interactive notebook that will allow users to further easily explore the predicted pKa shifts as a function of formulation variables.

Nanoplastics generated from plastic waste in our ecosystems are becoming increasingly prevalent as bulk plastics exposed to natural factors like water and sunlight fragment to the nanoscale over time. These incidental nanoplastics span a wide range of physicochemical properties, which makes studying nanoplastic interactions in biological systems difficult. Here, we characterized the behavior of incidental nanoplastics generated through mechanical abrasion within coacervate droplets to probe the surface properties of the nanoplastics. We used elastin-like polypeptides (ELPs) to create hydrophobic or charged coacervate microenvironments. Using optical microscopy and fluorescence quantification, we observed that nanoplastics made from polyethylene terephthalate (nPET), nylon 6 (nPA), and polystyrene (nPS) exhibited distinct partitioning behavior with more favorable interactions with hydrophobic droplets. This indicated that the hydrophobic polymer backbone was the predominate surface feature despite exposed functional groups of the incidental nanoplastics, in contrast to findings with model carboxylated latex nanospheres (nPS-COOH). Furthermore, the selective partitioning of incidental nanoplastics into the hydrophobic droplets was able to capture over 80% of nPET in solution, and after recovery of the protein droplet, was able to cumulatively capture over 75% of the nPET feedstock across multiple cycles. This work explores the nuanced surface characteristics of incidental nanoplastics, expands the application of coacervates as chemical probes, and demonstrates a biopolymer approach for effective nanoplastic removal.

Nanodiscs are nanoscale lipid bilayer membrane mimetics surrounded by two membrane scaffold proteins (MSP). They are widely used as soluble cassettes for membrane proteins and lipids in diverse applications. The original MSP1 was derived directly from human apolipoprotein A-1, and novel constructs have been adapted from this original design, including nanodiscs with larger sizes and covalent circularization. Here, we developed MSPs with a range of different fluorescent C-terminal protein tags, including a versatile HaloTag fusion. These fluorescent MSP were purified following typical MSP purification procedures with similar yield. Then, we demonstrate that fluorescent MSPs form nanodiscs with similar structure and stoichiometry to conventional MSP nanodiscs. These fluorescent MSP constructs enable a range of different applications and provide a versatile template for future design of nanodiscs with unique functions. For Table of Contents Only O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=109 SRC="FIGDIR/small/716332v1_ufig1.gif" ALT="Figure 1"> View larger version (49K): org.highwire.dtl.DTLVardef@f85870org.highwire.dtl.DTLVardef@764055org.highwire.dtl.DTLVardef@179b7c5org.highwire.dtl.DTLVardef@ff6a7_HPS_FORMAT_FIGEXP M_FIG C_FIG

Flexible and biocompatible piezoelectric materials are crucial for next-generation wearable and bio-integrated electronics. In this work, we report a sustainable bio-composite film by incorporating lysozyme, a naturally abundant protein, into a polyvinyl alcohol matrix to achieve efficient electromechanical conversion. The composite exploits the intrinsic molecular dipoles of lysozyme, which are effectively stabilized and aligned within the polymer network. Under applied bending strain and vertical pressure, the film exhibits a pronounced piezoelectric response, as evidenced by time-dependent electrical measurements under forward and reverse bias conditions. The deformation of -helices and other helical structures within lysozyme induces dipole reorientation and charge separation, generating a measurable electrical output. In contrast, pure polyvinyl alcohol films show no detectable response, confirming the essential role of lysozyme in the observed piezoelectricity. Furthermore, the device enables real-time human motion sensing, highlighting its potential for flexible, eco-friendly, and biocompatible electronic applications.

Intercalation of small molecules between DNA base pairs affects DNA conformation, disrupting essential cellular processes including replication, transcription, and repair. We investigated conformational changes in 18-mer DNA upon intercalation of doxorubicin, SYBR Gold and YOYO-1 using extensive MD simulations. Two main patterns for the intercalation were identified: RISE-type intercalation occurs between adjacent base pairs and extends the DNA helix with decreased twist angles, while OPEN-type intercalation proceeds through base-pair opening without significant DNA extension. Kinetic analysis revealed that association rates for intercalation followed the order: first YO-moiety (mono-intercalation) > SYBR Gold > doxorubicin > YOYO-1 (bis-intercalation). Free energy landscape showed that forces at DNA termini reached up to 117 pN during stretching. Notably, base pairs adjacent to intercalators were protected from strand separation, accompanied by additional helical unwinding. MM-PBSA/GBSA analysis revealed that the driving force for intercalation is the stacking energy, and the binding affinity was highest for minor groove binding. Persistence length decreased with single molecule binding but recovered with two molecules due to their electrostatic repulsion. Mechanical properties of intercalated DNA showed position-dependence, demonstrating that multiple intercalation modes coexist in solution. The heterogeneous nature of intercalation explains why experimental measurements reflect ensemble averages rather than single binding configurations.

Silver (Ag+) ions are known to be toxic to bacteria, cells, organisms and living systems; yet its impacts on the locomotion of surface-crawling organisms remain poorly quantified. Here we investigated the short-term (0-6 hours) effects of Ag+ ions on the locomotion of Drosophila melanogaster larvae on flat agarose surfaces containing Ag+ ions at different concentrations (0, 1, 10, and 100 mM). By quantifying their locomotion, we found that Drosophila larvae showed shorter accumulated distances and reduced crawling speed. Additionally, we quantified the go/stop dynamics and peristalsis of the larvae and observed that Ag+ ions disrupted the normal, rhythmic, peristaltic contraction of the larvae and "trapped" them in the stop phase. Such toxic effects were dependent on Ag+ concentration and exposure duration.

Reactive oxygen species generated during inflammation can oxidize viral envelope lipids, with outcomes ranging from modulated infectivity to viral inactivation. For SARS-CoV-2, the molecular mechanisms by which membrane lipid oxidation influences spike protein anchoring remain poorly understood. We use all-atom molecular dynamics (MD) simulations to quantify how graded oxidation of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) affects the anchoring of the SARS-CoV-2 spike transmembrane (TM) region in an endoplasmic-reticulum-Golgi intermediate compartment (ERGIC)-like multicomponent membrane. Viral envelopes containing 0, 25, 50, 75, and 100% oxidized POPC (PoxnoPC) corresponding to 0 - 55% oxidation of all PO-type phospholipids were simulated with the spike TM helix and cytoplasmic tail embedded in a POPC/POPE/POPI/POPS/cholesterol mixture. Steered MD and umbrella sampling were used to calculate the potential of mean force (PMF) for extracting the TM+CT region along the membrane normal. Partial oxidation (25 - 75% POPC) produced reductions in the detachment barrier that were not statistically distinguishable from the native system within the sampling uncertainty, whereas full POPC oxidation lowered the anchoring free energy by about 23% (from 606 {+/-} 39 to 464 {+/-} 38 kJ mol-1), indicating that oxidation of roughly half of the glycerophospholipids can measurably weaken spike-membrane coupling. Despite this reduction, the remaining barrier (about 180kBT ) is still large, suggesting that oxidation alone may be insufficient for spontaneous spike detachment and likely acts synergistically with mechanical forces during fusion or immune engagement. Analysis of acyl-chain order parameters, area per lipid, membrane thickness, number-density profiles, and lateral lipid clustering reveals that POPC peroxidation decreases lipid order, thins and softens the bilayer, and disrupts cholesterol-stabilized clusters that refer to large cooperative lipid assemblies (>10 lipids) identified via RDF-based clustering. These oxidation-induced changes reduce hydrophobic matching around the TM helix and facilitate its extraction from the viral envelope. Our results provide a mechanistic link between lipid peroxidation, membrane nanostructure, and spike anchoring, supporting lipid oxidation for example during cold atmospheric plasma or ozone treatment as a physically grounded contributing antiviral mechanism against SARS-CoV-2.

The scalable fabrication of stable colloidosomes with controlled permeability and defined multicompartmental architecture remains a critical challenge, limiting their broader use in molecular delivery and environmental remediation. Here, we develop a hybrid lipid-metal-organic framework (lipid-MOF) colloidosome assembled through an interfacial emulsification strategy that integrates the structural rigidity of ZIF-8 particles with lipid-mediated membrane stabilization. During assembly, ZIF-8 particles accumulate at the oil-water interface to form a shell, producing hollow micron-sized spherical colloidosomes. The resulting colloidosomes exhibit excellent colloidal stability in aqueous media for over 30 days with a zeta potential of approximately -50 mV. Nitrogen adsorption measurements reveal a surface area of 45 m2g-1 and an average pore width of 4 nm. Fluorescence imaging shows that hydrophobic Nile red preferentially partitions into the colloidosomal membrane, whereas hydrophilic fluorescein isothiocyanate (FITC) localize predominantly within the aqueous interior, enabling simultaneous encapsulation of molecules with contrasting polarity with loading efficiencies approaching 90%. Furthermore, the colloidosomes demonstrate rapid removal of model pollutants from water, achieving >90% removal of methylene blue and metal ions without stirring. Together, these results introduce lipid-MOF colloidosomes as a new class of hybrid platforms that unify structural stability, multicompartmental encapsulation, and efficient adsorption behavior, opening pathways toward sustainable platforms for drug delivery and environmental bioremediation.

Microplastic (MP) pollution, which is present in the ecosystem in vast quantities, adversely affects human health and the environment, making it imperative to develop methods for its mitigation. The challenge of detecting or capturing MPs could potentially be addressed using plastic-binding peptides (PBPs). The ideal PBP for MP remediation would not only bind strongly to plastic, but also have other properties such as high solubility in water or great binding specificity to a certain plastic. However, the scarcity or absence of known PBPs for common plastics along with the lack of methods that can discover PBPs with all of the desired properties precludes the development of peptide-based MP remediation strategies. In this study, we discovered short linear PBPs with high predicted water solubility and binding specificity by employing an in-silico discovery pipeline that combines deep learning and biophysical modeling. First, a long short-term memory (LSTM) network was trained on biophysical modeling data to predict peptide affinity to plastic. High affinity peptides were generated by pairing the trained LSTM with a Monte Carlo tree search (MCTS) algorithm. Molecular dynamics (MD) simulations showed that the PBPs discovered for polyethylene, the most common plastic, had 15% lower binding free energy than PBPs obtained using biophysical modeling alone. PBPs with both high affinity and high predicted solubility in water were found by including the CamSol solubility score in the MCTS peptide scoring function, increasing the average solubility score from 0.2 to 0.9, while only minimally decreasing affinity for polyethylene. The framework also discovered peptides with high binding specificity between polystyrene and polyethylene, two major constituents of MP pollution, using a competitive MCTS approach that optimized the difference in affinity between the two plastics. MD simulations showed that competitive MCTS increased the binding specificity of PBPs for polystyrene and identified peptides with relatively great preference for either of the two plastics. The framework can readily be applied to design PBPs for other types of plastic. Overall, the high-affinity PBPs with desirable properties discovered by marrying artificial intelligence and biophysics can be valuable for remediating MP pollution and protecting the health of humans and the environment.

Extracellular vesicles (EVs) are lipid spheres released from cells. Research utilizing EVs has met several hurdles owing to the small size of the majority of EVs and other nanoparticles (<150 nm) and the lack of detection technologies capable of providing high-throughput single particle measurements at this scale. The use of high-throughput single particle measurements is critical for the assessment of EV heterogeneity and abundance which are features often used to assess the development of isolation protocols or particle characterization. The Coulter principle, known in the field as resistive pulse sensing (RPS), has been used for several decades to size and count cells. More recently, this technology has evolved to accommodate nanoparticle analysis. In the last decade a platform utilizing microfluidic resistive pulse sensing (MRPS) has been demonstrated for nanoparticles, offering ergonomic characterization of nanoparticles along with utilizing open format data. To date, assessment of MRPS accuracy and reporting standards have not been assessed. With the aim of increasing data accuracy, ergonomics, and reporting transparency, we developed a microfluidic resistive pulse sensing post-acquisition analysis software (RPSPASS) application for automated cohort calibration, population gating, statistical output, QC plot generation, alternative data file outputs, and standardized reporting templates.

Medulloblastoma (MB) is an aggressive central nervous system (CNS) malignancy that primarily affects children and frequently exhibits metastasis to the leptomeninges of the brain and spinal cord. We developed a {beta}-Cyclodextrin-poly({beta}-Amino Ester) nanoparticle system to deliver the histone deactylase inhibitor (HDACi) Panobinostat to MB by the intrathecal route. Various imaging methods were utilized to study nanoparticle and payload fate following infusion into the cerebrospinal fluid (CSF) of mice via cisterna magna or lumbar access points. Nanoparticles dramatically improved penetration of hydrophobic small molecules into distal regions of the spinal cord. Panobinostat-loaded nanoparticles were effective at treating patient-derived MB, activating pharmacodynamic targets, slowing growth of the primary tumor, decreasing incidence of metastasis at the time of death, and ultimately prolonging survival. These studies provide insight into the mechanisms mediating transport of colloids and therapeutic molecules in the subarachnoid space and highlight new approaches for treating metastatic disease in the CNS.

It is an essential element of mechanobiology to measure the forces of biological cells. In microparticle traction force microscopy, they are inferred from the deformation of elastic microparticles. Two complementary variants have been introduced before: the volume method, which reconstructs surface stresses from the displacements of fiducial markers embedded inside the particles, and the surface method, which infers stresses directly from the deformation of the particle surface. However, a systematic comparison of the two methods has been lacking. Here, we quantitatively compare both approaches using simulated traction fields representing biologically relevant loading scenarios. We find that the surface method consistently reconstructs traction profiles with substantially lower errors than the volume method, which suffers from displacement tracking and stress calculation at the surface. At high noise levels, however, the performance gap becomes smaller. To compare the performance of the two methods in a realistic experimental setting, we developed DNA-based hydrogel microparticles equipped with both fluorescent surface labels and embedded fluorescent nanoparticles, enabling the direct comparison of the two methods within the same system. Compression experiments produced traction profiles consistent with Hertzian contact mechanics and confirmed the trends observed in the simulations. While our computational workflow establishes a framework to apply both methods, our experimental workflow establishes DNA microparticles as versatile and biocompatible probes for measuring cellular forces.

Pancreatic ductal adenocarcinoma (PDAC) remains difficult to treat with nucleic acid therapeutics because efficient intratumoral delivery is limited and off-target liver accumulation is common. Here, we developed a structure-activity map for intraperitoneally administered mRNA lipid nanoparticles (mRNA-LNPs) to identify formulation features that improve delivery to pancreatic tumors while reducing liver expression. A full-factorial library of 48 mRNA-LNP formulations was generated by varying ionizable lipid, sterol, phospholipid, and PEG-lipid components. Formulations were characterized for size, polydispersity, zeta potential, and encapsulation, then evaluated in an orthotopic KPC8060 pancreatic tumor model after intraperitoneal administration of firefly luciferase mRNA-loaded LNPs. Biodistribution was assessed by Rhodamine B fluorescence and functional delivery by luciferase expression 12 h after dosing. Lipid composition strongly influenced both physicochemical properties and in vivo performance. G0-C14-based formulations produced the smallest and most homogeneous particles, whereas FTT5-containing formulations were generally larger. Across the 48-formulation library, mRNA expression and nanoparticle biodistribution varied significantly among tumor, pancreas, liver, and spleen. Statistical, decision-tree, and predictive modeling analyses identified composition rules associated with organ-selective delivery. High tumor expression was associated primarily with G0-C14 combined with DSPC and {beta}-sitosterol, whereas liver expression was favored by C12-200 or DLin-MC3-DMA with DOPE and DSPE-PEG. Notably, a G0-C14/DSPC/DSPE-PEG formulation emerged as a lead candidate, producing a greater than 6-fold increase in tumor luciferase signal relative to the library median while reducing liver exposure by approximately 60%. Histopathology showed no treatment-related liver or lung toxicity. These findings define actionable formulation rules for tuning intraperitoneal mRNA-LNP delivery in PDAC and support further development of tumor-selective mRNA therapeutics for pancreatic cancer.

SignificanceQuantifying lipid droplet (LD) remodeling in 3D hepatic organoids is often limited to endpoint staining or phototoxic live fluorescence imaging, thereby obscuring droplet-level kinetics. AimWe aimed to develop a label-free method to track LD dynamics in living hepatic organoids under different fatty-acid loads. ApproachTime-lapse 3D refractive-index tomograms were acquired using holotomography and analyzed with a depth-adaptive, multi-threshold segmentation pipeline to quantify LD number, volume, sphericity, and refractive-index-derived concentration and dry mass at single-droplet resolution. ResultsOleic acid and linoleic acid induced LD accumulation while preserving organoid integrity, whereas palmitic acid triggered rapid structural collapse. Despite increases in total LD burden under both oleic acid and linoleic acid, droplet-level dynamics diverged: oleic acid produced volume-dominated accumulation via enlargement of fewer LDs and increased size heterogeneity, whereas linoleic acid produced number-dominated accumulation via sustained increases in LD number, yielding a more uniform population of small droplets. ConclusionsLabel-free holotomography with depth-adaptive analysis enables non-invasive, longitudinal, and multi-scale quantification of LD dynamics in intact organoids and reveals fatty-acid- dependent temporal modes of lipid storage. Statement of DiscoveryWe developed a label-free, longitudinal 3D holotomography framework with depth-adaptive lipid droplet segmentation that quantifies single-droplet dynamics in living mouse hepatic organoids. Using this platform, we found that oleic acid and linoleic acid induce LD accumulation via distinct strategies--oleic acid via droplet enlargement and linoleic acid via sustained increases in droplet number--while palmitic acid rapidly compromises organoid integrity.

Low- to moderate-intensity ultrasound (US) technologies are increasingly being used to non-invasively modulate biological function in both clinical and laboratory settings. Realizing the full potential of these approaches requires a detailed mechanistic understanding of how ultrasound interacts with living cells. Here, we developed a well-controlled experimental platform to expose adherent cells to ultrasound stimulation while monitoring cellular activation via calcium imaging. We show that cell activation is dependent on cell type and identify NIH3T3 fibroblasts as a particularly robust responder. Our findings indicate that acoustic streaming is the primary mechanism underlying ultrasound-induced activation in our in vitro experiments. Surprisingly, the investigation of calcium dynamics revealed that the observed cytoplasmic calcium elevation originates predominantly from intracellular stores rather than extracellular influx, with membrane ion channels not contributing directly to the response. Notably, the biomechanical property of the cell-cortex emerges as a critical determinant of the cells sensitivity to ultrasound. Overall, our results provide clear evidence that the underlying mechanistic response involves external and internal factors that modulate the ultrasound-cell interaction and highlight important mechanistic considerations for ultrasound-based strategies aimed at cellular stimulation.

Continuous monitoring of protein biomarkers could transform the management of acute and chronic diseases. Despite tremendous potential, wearable health monitors have remained largely limited to metabolites and small molecules. A key challenge is the limited availability of biointerfaces that reversibly track low-abundance proteins in vivo without user intervention. Here, we present the Differential Aptalyzer, a minimally invasive hydrogel microneedle platform for continuous monitoring of proteins in skin interstitial fluid. The platform combines high-affinity antibodies for selective target capture with aptamers for reversible electrochemical signal transduction. When integrated into a differential electrochemical chip and pulse-assisted sensor regeneration, this approach enables continuous monitoring of proteins in a wearable format. Using cardiac troponin I (cTnI) as a clinically-relevant model analyte, Differential Aptalyzer offers a broad dynamic range (0.003-0.640 ng/mL) and strong specificity against interfering proteins. Importantly, this platform reliably tracks both rising and falling exogenous cTnI levels injected into healthy mice, as well as endogenously elevated cTnI in a double-knockout mouse model of coronary artery disease, demonstrating its capability in continuous protein monitoring and identifying coronary artery disease cohorts.

Scaffolded DNA origami has become a valuable nanoscale tool for applications in biomedical and physical sciences. Critical to leveraging the modular and programmable properties of DNA origami nanodevices is access to the scaffold strand, a long single-stranded DNA (ssDNA) of precise length and sequence, which is folded into a compact shape via piecewise base-pairing with many staple strands, short ssDNA oligonucleotides. Current methods to produce and manipulate long ssDNA scaffolds can be costly, time-consuming, and cumbersome. In contrast, methods to produce and manipulate the sequence of double-stranded DNA (dsDNA) are efficient and scalable. Here, we present a method for the rapid isolation of target ssDNA sequences from a variety of dsDNA sources using oligonucleotides as blocking strands that bind continuously to the undesired strand, thereby releasing the target scaffold strand. We report successful ssDNA isolation from linear and supercoiled dsDNAs of various sequences and lengths, ranging from 769 to 15,101 nucleotides. In addition to isolating ssDNA, we demonstrated this approach enables folding of DNA origami directly from dsDNA templates using both blocking and staple strands in a single-pot thermally controlled reaction. Furthermore, we explore multi-scaffold and gene-encoding DNA origami structures, expanding the framework for application-based designs. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=82 SRC="FIGDIR/small/709872v1_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@1cc75dcorg.highwire.dtl.DTLVardef@4df8e2org.highwire.dtl.DTLVardef@10ed113org.highwire.dtl.DTLVardef@1c05bdd_HPS_FORMAT_FIGEXP M_FIG C_FIG

-Synuclein (Syn) remodels cellular membranes through interactions that involve both its structured, membrane-binding N-terminal domain (NTD) and intrinsically disordered C-terminal domain (CTD). While the amphipathic NTD helix is known to insert into lipid bilayers and generate curvature, the contribution of the acidic CTD remains unclear. Here, we dissect the individual and cooperative roles of these domains using Supported Bilayers with Excess Membrane Reservoir (SUPER) templates to quantify membrane remodeling via membrane fission and membrane morphological deformations (i.e., membrane budding and tubulation). We show that both the NTD and CTD independently remodel membranes, while full-length Syn exhibits greater remodeling ability than either the NTD or CTD in isolation. This result demonstrates a synergistic amplification between helix insertion of the NTD and the tethered, disordered CTD. To further probe the mechanism of membrane remodeling by the CTD, we modulated the chain length of the protein, the bulk ionic strength of the solution (i.e., charge screening), and applied relevant polymer scaling laws for disordered proteins. Our results suggest that the membrane remodeling mechanism for the disordered CTD is electrostatic in nature, stemming from protein-protein repulsion at elevated binding densities. Together, our findings reveal a cooperative energetic mechanism in which N-terminal helix insertion biases membrane curvature and the disordered, C-terminal domain adds an additional electrostatic component that helps to overcome the free energy barrier for membrane bending.

Dragonfly and cicada wing-inspired titanium nanopillar surfaces show promising bactericidal properties for antibacterial medical implant applications, but the precise mechanisms of bacteria-nanopillar interactions under hydrated conditions remain unclear. Cryo-electron tomography (cryo-ET) enables the visualisation of cellular organelles within their native hydrated cellular environment at molecular resolution. Visualising the bacteria-material interface on nanostructured surfaces by cryo transmission electron microscopy (cryo-TEM) requires the preparation of thin lamellae. Obtaining lamellae of bacteria directly on metal substrates while in a non-fixed and hydrated state requires cryo-focused ion beam (cryo-FIB) milling to isolate the targeted bacteria from the bulk sample. This approach faces additional challenges compared to tissues or cells on TEM grids, as titanium samples require a simultaneous cross-section of soft and hard materials at the same position and require vitrification, which embeds the sample in a thick layer of ice. Nonetheless, we demonstrate how to target a specific bacterium interacting with a titanium nanopillar surface using correlative cryo-fluorescence imaging, and how lamellae can still be prepared from vitrified samples by extracting the targeted bacterium and its surrounding as a small volume and transferring it to a receptor grid for thin lamella preparation, called targeted cryo-lift-out. Here, we outline the workflows and discuss their advantages and limitations for producing lamellae through lift-out techniques under cryogenic conditions, using methods that do not involve gas injection systems (GIS) for the lift-out transfer. These advances enhance cryo-ET applications, enabling in situ investigations of the interface between bacteria and nanopillars to effectively study the bactericidal mechanisms of biomimetic nature-inspired nanotopographies in a hydrated environment.