Multifunctional Material Building Blocks from Plant Pollen.

With its multifaceted nature, plant pollen serves not only as a key element in the reproductive cycle of seed plants but also as an influential contributor to environmental, human health, safety, and climate-related concerns. Pollen functions as a carrier of nutrients and organisms and holds a pivotal role in sustaining pollinator populations. Moreover, it is vital in ensuring the safety and quality of our food supply while presenting potential therapeutic applications. Pollen, often referred to as the diamond of the organic world due to its distinctive physical structures and properties, has been underappreciated from a material science and engineering standpoint. We propose adopting a more interdisciplinary and comprehensive approach to its study. Recent groundbreaking research has focused on the development of pollen-based building blocks that transform practically indestructible plant pollen into microgel, paper, and sponge, thereby unveiling numerous potential applications. In this review, we highlight the transformative potential of plant pollen as it is converted into a variety of building blocks, thereby unlocking myriad prospective applications through eco-friendly processing.

Elucidating Structural Configuration of Lipid Assemblies for mRNA Delivery Systems.

The development of mRNA delivery systems utilizing lipid-based assemblies holds immense potential for precise control of gene expression and targeted therapeutic interventions. Despite advancements in lipid-based gene delivery systems, a critical knowledge gap remains in understanding how the biophysical characteristics of lipid assemblies and mRNA complexes influence these systems. Herein, we investigate the biophysical properties of cationic liposomes and their role in shaping mRNA lipoplexes by comparing various fabrication methods. Notably, an innovative fabrication technique called the liposome under cryo-assembly (LUCA) cycle, involving a precisely controlled freeze-thaw-vortex process, produces distinctive onion-like concentric multilamellar structures in cationic DOTAP/DOPE liposomes, in contrast to a conventional extrusion method that yields unilamellar liposomes. The inclusion of short-chain DHPC lipids further modulates the structure of cationic liposomes, transforming them from multilamellar to unilamellar structures during the LUCA cycle. Furthermore, the biophysical and biological evaluations of mRNA lipoplexes unveil that the optimal N/P charge ratio in the lipoplex can vary depending on the structure of initial cationic liposomes. Cryo-EM structural analysis demonstrates that multilamellar cationic liposomes induce two distinct interlamellar spacings in cationic lipoplexes, emphasizing the significant impact of the liposome structures on the final structure of mRNA lipoplexes. Taken together, our results provide an intriguing insight into the relationship between lipid assembly structures and the biophysical characteristics of the resulting lipoplexes. These relationships may open the door for advancing lipid-based mRNA delivery systems through more streamlined manufacturing processes.

Interindividual- and blood-correlated sweat phenylalanine multimodal analytical biochips for tracking exercise metabolism.

In situ monitoring of endogenous amino acid loss through sweat can provide physiological insights into health and metabolism. However, existing amino acid biosensors are unable to quantitatively assess metabolic status during exercise and are rarely used to establish blood-sweat correlations because they only detect a single concentration indicator and disregard sweat rate. Here, we present a wearable multimodal biochip integrated with advanced electrochemical electrodes and multipurpose microfluidic channels that enables simultaneous quantification of multiple sweat indicators, including phenylalanine and chloride, as well as sweat rate. This combined measurement approach reveals a negative correlation between sweat phenylalanine levels and sweat rates among individuals, which further enables identification of individuals at high metabolic risk. By tracking phenylalanine fluctuations induced by protein intake during exercise and normalizing the concentration indicator by sweat rates to reduce interindividual variability, we demonstrate a reliable method to correlate and analyze sweat-blood phenylalanine levels for personal health monitoring.

Cholesterol-Enriched Hybrid Lipid Bilayer Formation on Inverse Phosphocholine Lipid-Functionalized Titanium Oxide Surfaces.

Hybrid lipid bilayers (HLBs) are rugged biomimetic cell membrane interfaces that can form on inorganic surfaces and be designed to contain biologically important components like cholesterol. In general, HLBs are formed by depositing phospholipids on top of a hydrophobic self-assembled monolayer (SAM) composed of one-tail amphiphiles, while recent findings have shown that two-tail amphiphiles such as inverse phosphocholine (CP) lipids can have advantageous properties to promote zwitterionic HLB formation. Herein, we explored the feasibility of fabricating cholesterol-enriched HLBs on CP SAM-functionalized TiO2 surfaces with the solvent exchange and vesicle fusion methods. All stages of the HLB fabrication process were tracked by quartz crystal microbalance-dissipation (QCM-D) measurements and revealed important differences in fabrication outcome depending on the chosen method. With the solvent exchange method, it was possible to fabricate HLBs with well-controlled cholesterol fractions up to ~65 mol% in the upper leaflet as confirmed by a methyl-ß-cyclodextrin (MßCD) extraction assay. In marked contrast, the vesicle fusion method was only effective at forming HLBs from precursor vesicles containing up to ~35 mol% cholesterol, but this performance was still superior to past results on hydrophilic SiO2. We discuss the contributing factors to the different efficiencies of the two methods as well as the general utility of two-tail CP SAMs as favorable interfaces to incorporate cholesterol into HLBs. Accordingly, our findings support that the solvent exchange method is a versatile tool to fabricate cholesterol-enriched HLBs on CP SAM-functionalized TiO2 surfaces.

Lipid Membrane Remodeling by the Micellar Aggregation of Long-Chain Unsaturated Fatty Acids for Sustainable Antimicrobial Strategies.

Antimicrobial fatty acids derived from natural sources and renewable feedstocks are promising surface-active substances with a wide range of applications. Their ability to target bacterial membrane in multiple mechanisms offers a promising antimicrobial approach for combating bacterial infections and preventing the development of drug-resistant strains, and it provides a sustainable strategy that aligns with growing environmental awareness compared to their synthetic counterparts. However, the interaction and destabilization of bacterial cell membranes by these amphiphilic compounds are not yet fully understood. Here, we investigated the concentration-dependent and time-dependent membrane interaction between long-chain unsaturated fatty acids-linolenic acid (LNA, C18:3), linoleic (LLA, C18:2), and oleic acid (OA, C18:1)-and the supported lipid bilayers (SLBs) using quartz crystal microbalance-dissipation (QCM-D) and fluorescence microscopy. We first determined the critical micelle concentration (CMC) of each compound using a fluorescence spectrophotometer and monitored the membrane interaction in real time following fatty acid treatment, whereby all micellar fatty acids elicited membrane-active behavior primarily above their respective CMC values. Specifically, LNA and LLA, which have higher degrees of unsaturation and CMC values of 160 µM and 60 µM, respectively, caused significant changes in the membrane with net |Δf| shifts of 23.2 ± 0.8 Hz and 21.4 ± 0.6 Hz and ΔD shifts of 5.2 ± 0.5 × 10-6 and 7.4 ± 0.5 × 10-6. On the other hand, OA, with the lowest unsaturation degree and CMC value of 20 µM, produced relatively less membrane change with a net |Δf| shift of 14.6 ± 2.2 Hz and ΔD shift of 8.8 ± 0.2 × 10-6. Both LNA and LLA required higher concentrations than OA to initiate membrane remodeling as their CMC values increased with the degree of unsaturation. Upon incubating with fluorescence-labeled model membranes, the fatty acids induced tubular morphological changes at concentrations above CMC. Taken together, our findings highlight the critical role of self-aggregation properties and the degree of unsaturated bonds in unsaturated long-chain fatty acids upon modulating membrane destabilization, suggesting potential applications in developing sustainable and effective antimicrobial strategies.

pH-Modulated Nanoarchitectonics for Enhancement of Multivalency-Induced Vesicle Shape Deformation at Receptor-Presenting Lipid Membrane Interfaces.

Multivalent ligand-receptor interactions between receptor-presenting lipid membranes and ligand-modified biological and biomimetic nanoparticles influence cellular entry and fusion processes. Environmental pH changes can drive these membrane-related interactions by affecting membrane nanomechanical properties. Quantitatively, however, the corresponding effects on high-curvature, sub-100 nm lipid vesicles are scarcely understood, especially in the multivalent binding context. Herein, we employed the label-free localized surface plasmon resonance (LSPR) sensing technique to track the multivalent attachment kinetics, shape deformation, and surface coverage of biotin ligand-functionalized, zwitterionic lipid vesicles with different ligand densities on a streptavidin receptor-coated supported lipid bilayer under varying pH conditions (4.5, 6, 7.5). Our results demonstrate that more extensive multivalent interactions caused greater vesicle shape deformation across the tested pH conditions, which affected vesicle surface packing as well. Notably, there were also pH-specific differences, i.e., a higher degree of vesicle shape deformation was triggered at a lower multivalent binding energy in pH 4.5 than in pH 6 and 7.5 conditions. These findings support that the nanomechanical properties of high-curvature lipid membranes, especially the membrane bending energy and the corresponding responsiveness to multivalent binding interactions, are sensitive to solution pH, and indicate that multivalency-induced vesicle shape deformation occurs slightly more readily in acidic pH conditions relevant to biological environments.

Lipid Membrane Interface Viewpoint: From Viral Entry to Antiviral and Vaccine Development.

Membrane-enveloped viruses are responsible for most viral pandemics in history, and more effort is needed to advance broadly applicable countermeasures to mitigate the impact of future outbreaks. In this Perspective, we discuss how biosensing techniques associated with lipid model membrane platforms are contributing to improving our mechanistic knowledge of membrane fusion and destabilization that is closely linked to viral entry as well as vaccine and antiviral drug development. A key benefit of these platforms is the simplicity of interpreting the results which can be complemented by other techniques to decipher more complicated biological observations and evaluate the biophysical functionalities that can be correlated to biological activities. Then, we introduce exciting application examples of membrane-targeting antivirals that have been refined over time and will continue to improve based on biophysical insights. Two ways to abrogate the function of viral membranes are introduced here: (1) selective disruption of the viral membrane structure and (2) alteration of the membrane component. While both methods are suitable for broadly useful antivirals, the latter also has the potential to produce an inactivated vaccine. Collectively, we emphasize how biosensing tools based on membrane interfacial science can provide valuable information that could be translated into biomedicines and improve their selectivity and performance.

Unraveling How Cholesterol Affects Multivalency-Induced Membrane Deformation of Sub-100 nm Lipid Vesicles.

Cholesterol plays a critical role in modulating the lipid membrane properties of biological and biomimetic systems and recent attention has focused on its role in the functions of sub-100 nm lipid vesicles and lipid nanoparticles. These functions often rely on multivalent ligand-receptor interactions involving membrane attachment and dynamic shape transformations while the extent to which cholesterol can influence such interaction processes is largely unknown. To address this question, herein, we investigated the attachment of sub-100 nm lipid vesicles containing varying cholesterol fractions (0-45 mol %) to membrane-mimicking supported lipid bilayer (SLB) platforms. Biotinylated lipids and streptavidin proteins were used as model ligands and receptors, respectively, while the localized surface plasmon resonance sensing technique was employed to track vesicle attachment kinetics in combination with analytical modeling of vesicle shape changes. Across various conditions mimicking low and high multivalency, our findings revealed that cholesterol-containing vesicles could bind to receptor-functionalized membranes but underwent appreciably less multivalency-induced shape deformation than vesicles without cholesterol, which can be explained by a cholesterol-mediated increase in membrane bending rigidity. Interestingly, the extent of vesicle deformation that occurred in response to increasingly strong multivalent interactions was less pronounced for vesicles with greater cholesterol fraction. The latter trend was rationalized by taking into account the strong dependence of the membrane bending energy on the area of the vesicle-SLB contact region and such insights can aid the engineering of membrane-enveloped nanoparticles with tailored biophysical properties.

Nanoarchitectonics-based model membrane platforms for probing membrane-disruptive interactions of odd-chain antimicrobial lipids.

The use of nanoscience tools to investigate how antimicrobial lipids disrupt phospholipid membranes has greatly advanced molecular-level biophysical understanding and opened the door to new application possibilities. Until now, relevant studies have focused on even-chain antimicrobial lipids while there remains an outstanding need to investigate the membrane-disruptive properties of odd-chain antimicrobial lipids that are known to be highly biologically active. Herein, using the quartz crystal microbalance-dissipation (QCM-D) and electrochemical impedance spectroscopy (EIS) techniques, we investigated how an 11-carbon, saturated fatty acid and its corresponding monoglyceride-termed undecanoic acid and monoundecanoin, respectively-disrupt membrane-mimicking phospholipid bilayers with different nanoarchitectures. QCM-D tracking revealed that undecanoic acid and monoundecanoin caused membrane tubulation and budding from supported lipid bilayers, respectively, and were only active above their experimentally determined critical micelle concentration (CMC) values. Monoundecanoin was more potent due to a lower CMC and electrochemical impedance spectroscopy (EIS) characterization demonstrated that monoundecanoin caused irreversible membrane disruption of a tethered lipid bilayer platform at sufficiently high compound concentrations, whereas undecanoic acid only induced transient membrane disruption. This integrated biophysical approach also led us to identify that the tested 11-carbon antimicrobial lipids cause more extensive membrane disruption than their respective 12-carbon analogues at 2 × CMC, which suggests that they could be promising molecular components within next-generation antimicrobial nanomedicine strategies.

Optimizing Plasmonic Gold Nanorod Deposition on Glass Surfaces for High-Sensitivity Refractometric Biosensing.

Owing to high surface sensitivity, gold nanorods (AuNRs) are widely used to construct surface-based nanoplasmonic biosensing platforms for label-free molecular diagnostic applications. A key fabrication step involves controlling AuNR deposition onto the target surface, which requires maximizing surface density while minimizing inter-particle aggregation, and is often achieved by surface functionalization with a self-assembled monolayer (SAM) prior to AuNR deposition. To date, existing studies have typically used a fixed concentration of SAM-forming organic molecules (0.2-10% v/v) while understanding how SAM density affects AuNR deposition and resulting sensing performance would be advantageous. Herein, we systematically investigated how controlling the (3-aminopropyl)triethoxysilane (APTES) concentration (1-30% v/v) during SAM preparation affects the fabrication of AuNR-coated glass surfaces for nanoplasmonic biosensing applications. Using scanning electron microscopy (SEM) and UV-visible spectroscopy, we identified an intermediate APTES concentration range that yielded the highest density of individually deposited AuNRs with minimal aggregation and also the highest peak wavelength in aqueous solution. Bulk refractive index sensitivity measurements indicated that the AuNR configuration had a strong effect on the sensing performance, and the corresponding wavelength-shift responses ranged from 125 to 290 nm per refractive index unit (RIU) depending on the APTES concentration used. Biosensing experiments involving protein detection and antigen-antibody interactions further demonstrated the high surface sensitivity of the optimized AuNR platform, especially in the low protein concentration range where the measurement shift was ~8-fold higher than that obtained with previously used sensing platforms.

Microplastics released from food containers can suppress lysosomal activity in mouse macrophages.

The ingestion and accumulation of microplastics is a serious threat to the health and survival of humans and other organisms given the increasing use of daily-use plastic products, especially during the COVID-19 pandemic. However, whether direct microplastic contamination from plastic packaging is a threat to human health remains unclear. We analyzed the market demand for plastic packaging in Asia-Pacific, North America, and Europe and identified the commonly used plastic food packaging products. We found that food containers exposed to high-temperature released more than 10 million microplastics per mL in water. Recycled plastic food packaging was demonstrated to continuously leach micro- and nanoplastics. In vitro cell engulfing experiments revealed that both micro- and nanoplastic leachates are readily taken up by murine macrophages without any preconditioning, and that short-term microplastic exposure may induce inflammation while exposure to nanoplastic substantially suppressed the lysosomal activities of macrophages. We demonstrated that the ingestion of micro- and nanoplastics released from food containers can exert differential negative effects on macrophage activities, proving that the explosive growth in the use of plastic packaging can poses significant health risks to consumers.

Inkjet-Printed Phospholipid Bilayers on Titanium Oxide Surfaces: Towards Functional Membrane Biointerfaces.

Functional biointerfaces hold broad significance for designing cell-responsive medical implants and sensor devices. Solid-supported phospholipid bilayers are a promising class of biological materials to build bioinspired thin-film coatings, as they can facilitate interactions with cell membranes. However, it remains challenging to fabricate lipid bilayers on medically relevant materials such as titanium oxide surfaces. There are also limitations in existing bilayer printing capabilities since most approaches are restricted to either deposition alone or to fixed microarray patterning. By combining advances in lipid surface chemistry and on-demand inkjet printing, we demonstrate the direct deposition and patterning of covalently tethered lipid bilayer membranes on titanium oxide surfaces, in ambient conditions and without any surface pretreatment process. The deposition conditions were evaluated by quartz crystal microbalance-dissipation (QCM-D) measurements, with corresponding resonance frequency (Δf) and energy dissipation (ΔD) shifts of around −25 Hz and <1 × 10−6, respectively, that indicated successful bilayer printing. The resulting printed phospholipid bilayers are stable in air and do not collapse following dehydration; through rehydration, the bilayers regain their functional properties, such as lateral mobility (>1 µm2/s diffusion coefficient), according to fluorescence recovery after photobleaching (FRAP) measurements. By taking advantage of the lipid bilayer patterned architectures and the unique features of titanium oxide's photoactivity, we further show how patterned cell culture arrays can be fabricated. Looking forward, this work presents new capabilities to achieve stable lipid bilayer patterns that can potentially be translated into implantable biomedical devices.

Streamlined Fabrication of Hybrid Lipid Bilayer Membranes on Titanium Oxide Surfaces: A Comparison of One- and Two-Tail SAM Molecules.

There is broad interest in fabricating cell-membrane-mimicking, hybrid lipid bilayer (HLB) coatings on titanium oxide surfaces for medical implant and drug delivery applications. However, existing fabrication strategies are complex, and there is an outstanding need to develop a streamlined method that can be performed quickly at room temperature. Towards this goal, herein, we characterized the room-temperature deposition kinetics and adlayer properties of one- and two-tail phosphonic acid-functionalized molecules on titanium oxide surfaces in various solvent systems and identified optimal conditions to prepare self-assembled monolayers (SAMs), upon which HLBs could be formed in select cases. Among the molecular candidates, we identified a two-tail molecule that formed a rigidly attached SAM to enable HLB fabrication via vesicle fusion for membrane-based biosensing applications. By contrast, vesicles adsorbed but did not rupture on SAMs composed of one-tail molecules. Our findings support that two-tail phosphonic acid SAMs offer superior capabilities for rapid HLB coating fabrication at room temperature, and these streamlined capabilities could be useful to prepare durable lipid bilayer coatings on titanium-based materials.

Recyclable and Reusable Natural Plant-Based Paper for Repeated Digital Printing and Unprinting.

Although paperless technologies are becoming ubiquitous, paper and paper-based materials remain one of the most widely used resources, predicted to exceed an annual total of 460 million metric tons by 2030. Given the environmental challenges, deleterious impact on natural resources, and waste associated with conventional wood-based paper manufacturing, developing more sustainable strategies to source, produce, and recycle paper from natural materials is essential. Here, the development and production of reusable and recyclable paper are reported. This approach offers a pathway for easily producing natural pollen grains via ecofriendly, economical, scalable, and low-energy fabrication routes. It is demonstrated that the pollen-based paper exhibits high-quality printability, readability, and erasability, enabling its reuse. Based on the pH-responsive morphological responses of engineered pollen materials, a method for hygro stable printing and on-demand unprinting is presented. The reusability of the pollen paper renders it more advantageous than conventional single-print wood-based paper. This study thus provides possible pathways to utilize non-allergenic pollen, which is renewable and naturally abundant, as a sustainable source of reusable paper. While this work primarily deals with paper, the methods described here can be extended to produce other products such as cartons and containers for the storage and transport of liquid and solid materials.

Selective Recognition of Phosphatidylinositol Phosphate Receptors by C-Terminal Tail of Mitotic Kinesin-like Protein 2 (MKlp2).

The mitotic kinesin-like protein 2 (MKlp2) plays a key role in the proper completion of cytokinetic abscission. Specifically, the C-terminal tail of MKlp2 (CTM peptides) offers a stable tethering on the plasma membrane and microtubule cytoskeleton in the midbody during abscission. However, little is known about the underlying mechanism of how the CTM peptides bind to the plasma membrane of the intercellular bridge. Herein, we identify the specific molecular interaction between the CTM peptides and phosphatidylinositol phosphate (PIP) receptors using quartz crystal microbalance-dissipation and atomic force microscopy force spectroscopic measurements. To systematically examine the effects of amino acids, we designed a series of synthetic 33-mer peptides derived from the wild-type (CTM1). First, we evaluated the peptide binding amount caused by electrostatic interactions based on 100% zwitterionic and 30% negatively charged model membranes, whereby the nonspecific attractions were nearly proportional to the net charge of peptides. Upon incubating with PIP-containing model membranes, the wild-type CTM1 and its truncated mutation showed significant PI(3)P-specific binding, which was evidenced by a 15-fold higher binding mass and 6-fold stronger adhesion force compared to other negatively charged membranes. The extent of the specific binding was predominantly dependent on the existence of S21, whereby substitution or deletion of S21 significantly hindered the binding affinity. Taken together, our findings based on a correlative measurement platform enabled the quantification of the nonelectrostatic, selective binding interactions of the C-terminal of MKlp2 to certain PIP receptors and contributed to understanding the molecular mechanisms on complete cytokinetic abscission in cells.

Multivalency-Induced Shape Deformation of Nanoscale Lipid Vesicles: Size-Dependent Membrane Bending Effects.

The size of membrane-enveloped virus particles, exosomes, and lipid vesicles strongly impacts functional properties in biological and applied contexts. Multivalent ligand-receptor interactions involving nanoparticle shape deformation are critical to such functions, yet the corresponding effect of nanoparticle size remains largely elusive. Herein, using an indirect nanoplasmonic sensing approach, we investigated how the nanoscale size properties of ligand-modified lipid vesicles affect real-time binding interactions, especially vesicle deformation processes, with a receptor-modified, cell membrane-mimicking platform. Together with theoretical analyses, our findings reveal a pronounced, size-dependent transition in the membrane bending properties of nanoscale lipid vesicles between 60 and 180 nm in diameter. For smaller vesicles, a large membrane bending energy enhanced vesicle stiffness while the osmotic pressure energy was the dominant modulating factor for larger, less stiff vesicles. These findings advance our fundamental understanding of how nanoparticle size affects multivalency-induced nanoparticle shape deformation and can provide guidance for the design of biomimetic nanoparticles with tailored nanomechanical properties.

Thermodynamic Modeling of Solvent-Assisted Lipid Bilayer Formation Process.

The solvent-assisted lipid bilayer (SALB) formation method provides a simple and efficient, microfluidic-based strategy to fabricate supported lipid bilayers (SLBs) with rich compositional diversity on a wide range of solid supports. While various studies have been performed to characterize SLBs formed using the SALB method, relatively limited work has been carried out to understand the underlying mechanisms of SALB formation under various experimental conditions. Through thermodynamic modeling, we studied the experimental parameters that affect the SALB formation process, including substrate surface properties, initial lipid concentration, and temperature. It was found that all the parameters are critically important to successfully form high-quality SLBs. The model also helps to identify the range of parameter space within which conformal, homogeneous SLBs can be fabricated, and provides mechanistic guidance to optimize experimental conditions for lipid membrane-related applications.

Nanoarchitectured air-stable supported lipid bilayer incorporating sucrose-bicelle complex system.

Cell-membrane-mimicking supported lipid bilayers (SLBs) provide an ultrathin, self-assembled layer that forms on solid supports and can exhibit antifouling, signaling, and transport properties among various possible functions. While recent material innovations have increased the number of practically useful SLB fabrication methods, typical SLB platforms only work in aqueous environments and are prone to fluidity loss and lipid-bilayer collapse upon air exposure, which limits industrial applicability. To address this issue, herein, we developed sucrose-bicelle complex system to fabricate air-stable SLBs that were laterally mobile upon rehydration. SLBs were fabricated from bicelles in the presence of up to 40 wt% sucrose, which was verified by quartz crystal microbalance-dissipation (QCM-D) and fluorescence recovery after photobleaching (FRAP) experiments. The sucrose fraction in the system was an important factor; while 40 wt% sucrose induced lipid aggregation and defects on SLBs after the dehydration-rehydration process, 20 wt% sucrose yielded SLBs that exhibited fully recovered lateral mobility after these processes. Taken together, these findings demonstrate that sucrose-bicelle complex system can facilitate one-step fabrication of air-stable SLBs that can be useful for a wide range of biointerfacial science applications.

Role of Membrane Stretch in Adsorption of Antiviral Peptides onto Lipid Membranes and Membrane Pore Formation.

Many medically important viruses are enveloped viruses, which are surrounded by a structurally conserved, host-derived lipid membrane coating. Agents that target and disrupt this membrane coating could potentially function as broad-spectrum antiviral drugs. The amphipathic α-helical (AH) peptide derived from the N-terminus of the hepatitis C virus NS5A protein is one such candidate and has been demonstrated to be able to selectively rupture lipid vesicles in the size range of viruses (<160 nm diameter). However, the mechanism underlying this membrane curvature selectivity remains elusive. In this study, we have performed molecular dynamics simulations to study the binding of the AH peptide to model membranes that are stretched to resemble the looser lipid headgroup packing present on highly curved outer membranes of nanoscale vesicles. We found that the AH peptide binds more favorably to membranes that are stretched. In addition, a tetrameric placement of peptides across the membrane induced stable pore formation in the stretched membrane. Thus, our results suggest that the AH peptide senses the high curvature of nanoscale vesicles via the enhanced exposure of lipid packing defects induced by membrane area strain.

Digital printing of shape-morphing natural materials.

We demonstrate how programmable shape evolution and deformation can be induced in plant-based natural materials through standard digital printing technologies. With nonallergenic pollen paper as the substrate material, we show how specific geometrical features and architectures can be custom designed through digital printing of patterns to modulate hygrophobicity, geometry, and complex shapes. These autonomously hygromorphing configurations can be "frozen" by postprocessing coatings to meet the needs of a wide spectrum of uses and applications. Through computational simulations involving the finite element method and accompanying experiments, we develop quantitative insights and a general framework for creating complex shapes in eco-friendly natural materials with potential sustainable applications for scalable manufacturing.