Fabrication and characterization of thin self-rolling film for anti-inflammatory drug delivery.

Thin films have been identified as an alternative approach for targeting sensitive site as drug delivery tool. In this work, the preparation of self-rolling thin films to form tubes for wound healing and easy placement (e.g.

Formation of a Controllable Diffusion Barrier Layer on the Surface of Polydimethylsiloxane Films by Infrared Laser Irradiation.

Developing a diffusion barrier layer on material interfaces has potential applications in various fields such as in packaging materials, pharmaceuticals, chemical filtration, microelectronics, and medical devices. Although numerous physical and chemical methods have been proposed to generate the diffusion barrier layer, the complexity of fabrication techniques and the high manufacturing costs limit their practical utility. Here, we propose an innovative approach to fabricate the diffusion barrier layer by irradiating poly(dimethylsiloxane) (PDMS) with a mid-infrared (λ = 10.

In silico analysis shows that dynamic changes in curvature guide cell migration over long distances.

In vitro experiments have shown that cell scale curvatures influence cell migration; cells avoid convex hills and settle in concave valleys. However, it is not known whether dynamic changes in curvature can guide cell migration. This study extends a previous in-silico model to explore the effects over time of changing the substrate curvature on cell migration guidance.

Self-Assembly of Soot Nanoparticles on the Surface of Resistively Heated Carbon Microtubes in Near-Hexagonal Arrays of Micropyramids.

Almost regular hexagonal arrays of microscopic pyramids consisting of soot nanoparticles are formed on the surface of graphitized hollow filaments, which are resistively heated to ∼1800-2400 °C under an Ar atmosphere containing trace amounts of oxygen (∼300 ppm). At higher temperatures ( > 2300 °C, approximately) the soot particles are represented mainly by multishell carbon nano-onions. The height and width of the pyramids are strongly dependent on the temperature of the resistive heating, diminishing from 5 to 10 μm at ≈ 1800 °C to ∼1 μm at 2300-2400 °C.

Bioresorbable Bilayered Elastomer/Hydrogel Constructs with Gradual Interfaces for the Fast Actuation of Self-Rolling Tubes.

In the biomedical field, self-rolling materials provide interesting opportunities to develop medical devices suitable for drug or cell encapsulation. However, to date, a major limitation for medical applications is the use of non-biodegradable and non-biocompatible polymers that are often reported for such applications or the slow actuation witnessed with degradable systems. In this work, biodegradable self-rolling tubes that exhibit a spontaneous and rapid actuation when immersed in water are designed.

Epithelial cells adapt to curvature induction via transient active osmotic swelling.

Generation of tissue curvature is essential to morphogenesis. However, how cells adapt to changing curvature is still unknown because tools to dynamically control curvature in vitro are lacking. Here, we developed self-rolling substrates to study how flat epithelial cell monolayers adapt to a rapid anisotropic change of curvature.

Biphasic Drug Release from Rolled-Up Gelatin Capsules with a Cylindrical Cavity.

Biphasic drug delivery systems are used for quick release of a specific amount of drug for immediate amelioration of a patient's state, followed by sustained release, to avoid repeated administration. This type of delivery is often necessary for pain management and the treatment of many pathologies, such as migraines, hypertension, and insomnia. In this work, we propose a novel architecture of a biphasic release media that does not need the rapidly disintegrating layer and that allows for easily setting the sustained release rate.

Laser-Assisted Strain Engineering of Thin Elastomer Films to Form Variable Wavy Substrates for Cell Culture.

Endothelial and epithelial cells usually grow on a curved environment, at the surface of organs, which many techniques have tried to reproduce. Here a simple method is proposed to control curvature of the substrate. Prestrained thin elastomer films are treated by infrared laser irradiation in order to rigidify the surface of the film.

Time-programmed release of fluoroscein isocyanate dextran from micro-pattern-designed polymer scrolls.

In this article we present a relevant strategy for a non-trivial time-programmed release of water-soluble macromolecules from biocompatible μ-containers. The system is based on self-scrolled chitosan acetate (CA) fibers, encapsulated in a poly(dimethylsiloxane) matrix. Mass transfer between a fiber and the external environment takes place via the only opened extremity of the fiber.

Self-scrolling ability of differentially acetylated chitosan film.

Chitosan film cast on a glass slide was exposed to acetic anhydride vapor, resulting in an acetylation gradient in the film, with preferential acetylation of the exposed surface. The difference in degree of acetylation between the two surfaces of the peeled film was confirmed by attenuated total reflection infrared spectroscopy. Upon immersion of the film in water, differential swelling occurred because the more highly acetylated surface absorbed less water, and the resulting bending moment caused self-scrolling with the more highly acetylated surface inside.

Vapour processed self-rolled poly(dimethylsiloxane) microcapillaries form microfluidic devices with engineered inner surface.

We propose a microfluidics device whose main functional part consists of a microcapillary produced by the self-rolling of a thin poly(dimethylsiloxane) film. Rolling is caused by inhomogeneous swelling of the film, pre-treated by oxygen plasma, in the vapour of chloroform. The capillaries are integrated with external electrical circuits by co-rolling electrodes and micro-resistors.

Self-rolled polymer tubes: novel tools for microfluidics, microbiology, and drug-delivery systems.

Recent work on the fabrication of tubular microstructures via self-rolling of thin, bilayer polymer films is reviewed. A bending moment in the films arises due to the swelling of one component of the bilayer in a selective solvent. The inner diameters of the tubes vary from hundreds of nanometers to dozens of micrometers.

Electrically conductive hexagonally ordered nanoporous membranes produced by ion-beam induced carbonization of block-copolymer precursors.

Highly ordered carbonized nanoporous membranes are produced by ion-beam treatment of self-assembled block copolymer precursor films. The membranes are electrically conductive, as verified by scanning tunnelling microscopy (STM) measurements. The carbonization degree is investigated by means of Raman and infrared (IR) spectroscopy, and the morphology of the films via transmission electron microscopy (TEM).

Fabrication of metallic microtubes using self-rolled polymer tubes as templates.

We present a novel approach for fabricating single and bimetallic (gold, titanium) (Au, Ti, Au/Ti) microtubes with very high aspect ratio from self-rolled polymer templates. The polymer microtubes used as the template were generated by self-rolling of thin polymer bilayer films (polystyrene/poly(4-vinylpyridine) (PS/P4VP) gradually released from a solid substrate. The self-rolling was introduced in the polymer bilayer by swelling the bottom P4VP layer in dodecylbenzenesulfonic acid (DBSA) solution, which was opposed by a stiff top PS layer.