In this letter, we describe a method to control the organization and thickness of multilayered phospholipid films. The meniscus an organic solution molecules was dragged at speed v on solid substrate under controlled temperature forced convection, leading deposition dried film with h in range 20-200 nm. We found two distinct regimes dominating deposition. At low speeds, accumulate near contact line form dry behind (evaporation regime). high speed, viscous forces become predominant pull out...

We study the effect of surfactants on deposits formed after evaporation colloidal suspension drops, at initial concentrations lower than critical micellar concentrations, for various particle/surfactant mixtures. show that surfactant-mediated interactions between particles and liquid–gas (LG) liquid–solid (LS) interfaces, rather flow patterns, primarily define morphology dry deposit in a robust reproducible manner. For like-charged mixtures, most form ring-shaped (according to so-called...

Abstract Thermal annealing is usually needed to direct the assembly of multiple complementary DNA strands into desired entities. We show that, with a magnesium-free buffer containing NaCl, complex cocktails and proteins can self-assemble isothermally, at room or physiological temperature, user-defined nanostructures, such as origamis, single-stranded tile assemblies nanogrids. In situ, time-resolved observation reveals that this self-assembly thermodynamically controlled, proceeds through...

Ace of hearts: Liquid droplets can be manipulated in a controlled fashion along trajectories any desired shape (such as heart, see picture) by using light to create wavelength-dependent interfacial tension gradient at liquid/liquid interface. In this new phenomenon, the "chromocapillary effect", an flow generates droplet motion direction opposite gradient. Detailed facts importance specialist readers are published "Supporting Information". Such documents peer-reviewed, but not copy-edited or...

Compaction is the process in which a large DNA molecule undergoes transition between an elongated conformation and very compact form. In nature, compaction occurs to package genomic material inside tiny spaces such as viral capsids cell nuclei. vitro, several strategies exist DNA. this review, we first provide physico-chemical description of phenomenon, focusing on modes compaction, types agents chemical physical parameters that control its reverse process, decompaction. We then describe...

Liquid marbles, that is, liquid drops coated by a hydrophobic powder, do not wet any solid or substrate, making their transport and manipulation both highly desirable challenging. Herein, we describe the light-driven of floating marbles emphasize surprising motion behavior. are deposited on water solution containing photosensitive surfactants. Irradiation generates photoreversible Marangoni flows toward UV light away from blue when thickness substrate is large enough (Marangoni regime)....

The coffee-ring effect denotes the accumulation of particles at edge an evaporating sessile drop pinned on a substrate. Because it can be detected by simple visual inspection, this ubiquitous phenomenon envisioned as robust and cost-effective diagnostic tool. Toward direction, here we systematically analyze deposit morphology drying drops containing polystyrene different surface properties with various proteins (bovine serum albumin (BSA) forms hemoglobin). We show that patterns reveal...

The evaporation of a drop colloidal suspension pinned on substrate usually results in ring particles accumulated at the periphery initial drop. Intense research has been devoted to understanding, suppressing and ultimately controlling this so-called coffee-ring effect (CRE). Although crucial role flow patterns CRE thoroughly investigated, interactions phenomenon largely neglected. This Concept paper reviews recent works field shows that colloids with (and at) liquid-solid liquid-gas...

Abstract The magnetic actuation of deposited drops has mainly relied on volume forces exerted the liquid to be transported, which is poorly efficient with conventional diamagnetic liquids such as water and oil, unless magnetosensitive particles are added. Herein, we describe a new additive‐free way magnetically control motion discrete entities. Our strategy consists using paramagnetic deformable substrate direct, magnet, various floating entities, ranging from naked marbles. A broad variety...

Using functional proteins for therapeutic purposes due to their high selectivity and/or catalytic properties can enable the control of various cellular processes; however, transport active inside living cells remains a major challenge. In contrast, intracellular delivery nucleic acids has become routine method number applications in gene therapy, genome editing, or immunization. Here we report functionalizable platform constituting DNA–protein nanogel carriers cross-linked through...

Artificial biomolecular nanotubes are a promising approach to building materials mimicking the capacity of cellular cytoskeleton grow and self-organize dynamically. Nucleic acid nanotechnology has demonstrated variety self-assembling with programmable, robust features morphological similarities actual components. However, their production typically requires thermal annealing, which not only poses general constraint on potential applications but is also incompatible physiological conditions....

Monodisperse silver rings with nanometer-scale diameters (see Figure) are produced due to the ability of DNA organize into toroidal condensates well-defined shapes and sizes upon its interaction multications. Silver ions can bind residual negative surface charge condensed DNA, then reduced metal yield toroids coated a thin shell.

Abstract When a colloidal drop dries on surface, most of the particles accumulate at periphery, yielding characteristic ring‐shaped pattern. This so‐called coffee‐ring effect (CRE) is observed in any pinned evaporating containing non‐volatile solutes. Here, CRE dynamically controlled for first time by using light, and an unprecedented reconfigurability deposit profile demonstrated. achieved through new mechanism where particle stickiness optically tuned demand, thus offering reliable...

Abstract We report the synthesis and characterisation of photosensitive cationic surfactants with various hydrophobic tail lengths. These molecules, called AzoC x , are used as nucleic acid binders (pNABs) applied to photocontrol DNA conformation. All these molecules induce compaction in a photodependent way, originating polarity their tails. show that increasing hydrophobicity strongly enhances efficiencies but reduces possibility reversible Optimal performance was achieved AzoC5, which...

Controlled particle deposition on surfaces is crucial for both exploiting collective properties of particles and their integration into devices. Most available methods depend intrinsic either the substrate or to be deposited making them difficult apply complex, naturally occurring industrial formulations. Here we describe a new strategy pattern from an evaporating drop, regardless inherent characteristics suspension composition. We use light generate Marangoni surface stresses resulting in...

The mixing of confined liquids is a central yet challenging operation in miniaturized devices. Microfluidic usually achieved with passive mixers that are robust but poorly flexible, or active offer dynamic control mainly rely on electrical mechanical transducers, which increase the fragility, cost, and complexity device. Here, we describe first remote reversible microfluidic triggered by light illumination simply provided an external LED approach based light-induced generation water...

We study the behavior of multicomponent giant unilamellar vesicles (GUVs) in presence AzoTAB, a photosensitive surfactant. GUVs are made an equimolar ratio dioleoylphosphatidylcholine (DOPC) and dipalmitoylphosphatidylcholine (DPPC) various amounts cholesterol (Chol), where lipid membrane shows phase separation into DPPC-rich liquid-ordered (Lo) DOPC-rich liquid-disordered (Ld) phase. find that UV illumination at 365 nm for 1 s induces bursting significant fraction GUV population. The...

External control of DNA melting and hybridization, a key step in bio- nanotechnology, is commonly achieved with temperature. The use light to direct this process challenging alternative, which has been only possible modification, such as covalent grafting or mismatch introduction, so far. Here we describe the first photocontrol that relies on addition molecule noncovalently interacts unmodified affects its properties photoreversible highly robust manner, without any prerequisite length...

We elaborated a versatile experimental model of chromatin which consists single chain long duplex DNA that interacts with well-defined cationic nanoparticles various sizes. found the compaction by is stepwise and progressive at single-chain level. It controlled ability to wrap nanoparticles, more efficient for larger particles and, similar DNA-histone interaction, optimal physiological salt concentration.

We studied the evolution of oil-in-oil (O/O) and water-in-oil (W/O) phospholipid-coated micro-droplets at an oil/water interface. found that, in both cases, spontaneously transferred from oil phase to water phase. O/O transformed into oil-in-water micro-droplets, while W/O led formation liposomes.

The compaction of long duplex DNA by cationic nanoparticles (NP) used as a primary model histone core particles has been investigated. We have systematically studied the effect salt concentration, particle size, and charge means single-molecule observations-fluorescence microscopy (FM) transmission electron (TEM)-and molecular dynamics (MD) simulations. found that large-scale is progressive proceeds through formation beads-on-a-string structures various morphologies. adsorbed amount per...

To understand non-trivial biological functions, it is crucial to develop minimal synthetic models that capture their basic features. Here, we demonstrate a sequence-independent, reversible control of transcription and gene expression using photosensitive nucleic acid binder (pNAB). By introducing pNAB whose affinity for acids tuned by light, in vitro RNA production, EGFP translation, GFP (a set reactions including both translation) were successfully inhibited the dark recovered after short...

Abstract An integrated smart microfluidic device consisting of nickel micropillars, microvalves, and microchannels was developed for specific capture sorting cells. A regular hexagonal array micropillars on the bottom a microchannel by standard photolithography, which can generate strong induced magnetic field gradients under an external to efficiently trap superparamagnetic beads (SPMBs) in flowing stream, forming bed with sufficient as zone. Fluids could be manipulated programmed...