Nanotopography promotes cardiogenesis of pluripotent stem cell-derived embryoid bodies through focal adhesion kinase signaling.

Controlling the microenvironment surrounding the pluripotent stem cells (PSCs) is a pivotal strategy for regulating cellular differentiation. Surface nanotopography is one of the key factors influencing the lineage-specific differentiation of PSCs. However, much of the underlying mechanism remains unknown.

The effect of low-intensity cold atmospheric plasma jet on photoaging-induced hyperpigmentation in mouse model.

Background: Cold atmospheric plasma (CAP) produces reactive oxygen/nitrogen species (RONS) in the target and can induce cytoprotective effects by activating hormesis-related pathways when its intensity is in the low range.

Objectives: The aim of this study is to evaluate the effect of low-intensified CAP (LICAP) on skin with photoaging-induced hyperpigmentation in an animal model.

Methods: Changes in cell viability and RONS production following LICAP treatment were measured.

Low-intensity cold atmospheric plasma reduces wrinkles on photoaged skin through hormetic induction of extracellular matrix protein expression in dermal fibroblasts.

Background: Recent evidence indicates that cold atmospheric plasma (CAP) can upregulate the production of extracellular matrix (ECM) proteins in dermal fibroblasts and enhance transdermal drug delivery when applied at a low intensity.

Objectives: The aim of this study was to evaluate the effect of low-intensity CAP (LICAP) on photoaging-induced wrinkles in an animal model and the expression profiles of ECM proteins in human dermal fibroblasts.

Methods: Each group was subjected to photoaging induction and allocated to therapy (LICAP, topical polylactic acid (PLA), or both).

Static and Dynamic Biomaterial Engineering for Cell Modulation.

In the biological microenvironment, cells are surrounded by an extracellular matrix (ECM), with which they dynamically interact during various biological processes. Specifically, the physical and chemical properties of the ECM work cooperatively to influence the behavior and fate of cells directly and indirectly, which invokes various physiological responses in the body. Hence, efficient strategies to modulate cellular responses for a specific purpose have become important for various scientific fields such as biology, pharmacy, and medicine.

Assessment of Cellular Uptake Efficiency According to Multiple Inhibitors of FeO-Au Core-Shell Nanoparticles: Possibility to Control Specific Endocytosis in Colorectal Cancer Cells.

Magnetite (FeO)-gold (Au) core-shell nanoparticles (NPs) have unique magnetic and optical properties. When combined with biological moieties, these NPs can offer new strategies for biomedical applications, such as drug delivery and cancer targeting. Here, we present an effective method for the controllable cellular uptake of magnetic core-shell NP systems combined with biological moieties.

Regulating response and leukocyte adhesion of human endothelial cell by gradient nanohole substrate.

Understanding signals in the microenvironment that regulate endothelial cell behavior are important in tissue engineering. Although many studies have examined the cellular effects of nanotopography, no study has investigated the functional regulation of human endothelial cells grown on nano-sized gradient hole substrate. We examined the cellular response of human umbilical vein endothelial cells (HUVECs) by using a gradient nanohole substrate (GHS) with three different types of nanohole patterns (HP): which diameters were described in HP1, 120-200 nm; HP2, 200-280 nm; HP3, 280-360 nm.

Nanotopographical regulation of pancreatic islet-like cluster formation from human pluripotent stem cells using a gradient-pattern chip.

Bioengineering approaches to regulate stem cell fates aim to recapitulate the in vivo microenvironment. In recent years, manipulating the micro- and nano-scale topography of the stem cell niche has gained considerable interest for the purposes of controlling extrinsic mechanical cues to regulate stem cell fate and behavior in vitro. Here, we established an optimal nanotopographical system to improve 3-dimensional (3D) differentiation of pancreatic cells from human pluripotent stem cells (hPSCs) by testing gradient-pattern chips of nano-scale polystyrene surface structures with varying sizes and shapes.

Fabrication of Gradient Nanopattern by Thermal Nanoimprinting Technique and Screening of the Response of Human Endothelial Colony-forming Cells.

Nanotopography can be found in various extracellular matrices (ECMs) around the body and is known to have important regulatory actions upon cellular reactions. However, it is difficult to determine the relation between the size of a nanostructure and the responses of cells owing to the lack of proper screening tools. Here, we show the development of reproducible and cost-effective gradient nanopattern plates for the manipulation of cellular responses.

Manipulation of the response of human endothelial colony-forming cells by focal adhesion assembly using gradient nanopattern plates.

Unlabelled: Nanotopography plays a pivotal role in the regulation of cellular responses. Nonetheless, little is known about how the gradient size of nanostructural stimuli alters the responses of endothelial progenitor cells without chemical factors. Herein, the fabrication of gradient nanopattern plates intended to mimic microenvironment nanotopography is described.

Nanotopological plate stimulates osteogenic differentiation through TAZ activation.

The topographical environment, which mimics the stem cell niche, provides mechanical cues to regulate the differentiation of mesenchymal stem cells (MSC). Diverse topographical variations have been engineered to investigate cellular responses; however, the types of mechanical parameters that affect cells, and their underlying mechanisms remain largely unknown. In this study, we screened nanotopological pillars with size gradient to activate transcriptional coactivator with PDZ binding motif (TAZ), which stimulates osteogenesis of MSC.

Nanopillar Surface Topology Promotes Cardiomyocyte Differentiation through Cofilin-Mediated Cytoskeleton Rearrangement.

Nanoscaled surface patterning is an emerging potential method of directing the fate of stem cells. We adopted nanoscaled pillar gradient patterned cell culture plates with three diameter gradients [280-360 (GP 280/360), 200-280 (GP 200/280), and 120-200 nm (GP 120/200)] and investigated their cell fate-modifying effect on multipotent fetal liver kinase 1-positive mesodermal precursor cells (Flk1 MPCs) derived from embryonic stem cells. We observed increased cell proliferation and colony formation of the Flk1 MPCs on the nanopattern plates.

Period-chirped gratings fabricated by laser interference lithography with a concave Lloyd's mirror.

We developed a laser interference lithography (LIL) system for fabrication of period-chirped gratings, which would be useful for sophisticated optical components. Despite its simplicity, the developed LIL system, based on a Lloyd's mirror interferometer with a cylindrically concave mirror, can generate chirped gratings, yet over a large area at high throughput owing to the nature of LIL. We have derived exact theoretical equations needed for system design, built the LIL system, and subsequently realized period-chirped gratings.

Nanotopographical control for maintaining undifferentiated human embryonic stem cell colonies in feeder free conditions.

Recently emerging evidence has indicated surface nanotopography as an important physical parameter in the stem cell niche for regulating cell fate and behaviors for various types of stem cells. In this study, a substrate featuring arrays of increasing nanopillar diameter was devised to investigate the effects of varying surface nanotopography on the maintenance of undifferentiated human embryonic stem cells (hESC) colonies in the absence of feeder cells. Single hESCs cultured across gradient nanopattern (G-Np) substrate were generally organized into compact colonies, and expressed higher levels of undifferentiated markers compared to those cultured on the unstructured control substrate.

A simple and fast fabrication of a both self-cleanable and deep-UV antireflective quartz nanostructured surface.

Both self-cleanability and antireflectivity were achieved on quartz surfaces by forming heptadecafluoro-1,1,2,2-tetrahydrodecyltrichlorosilane self-assembled monolayer after fabrication of nanostructures with a mask-free method. By exposing polymethylmethacrylate spin-coated quartz plates to O2 reactive ion etching (RIE) and CF4 RIE successively, three well-defined types of nanopillar arrays were generated: A2, A8, and A11 patterns with average pillar widths of 33 ± 4 nm, 55 ± 5 nm, and 73 ± 14 nm, respectively, were formed. All the fabrication processes including the final cleaning can be finished within 4 h.

Combined laser interference and photolithography patterning of a hybrid mask mold for nanoimprint lithography.

A lithography technique that combines laser interference lithography (LIL) and photolithography, which can be a valuable technique for the low cost production of microscale and nanoscale hybrid mask molds, is proposed. LIL is a maskless process which allows the production of periodic nanoscale structures quickly, uniformly, and over large areas. A 257 nm wavelength Ar-Ion laser is utilized for the LIL process incorporating a Lloyd's mirror one beam inteferometer.

Effects of surface nano-topography on human osteoblast filopodia.

Anchorage-dependent cells growing over a substratum require stable adhesion areas on the surface for the next cellular activities. The adhesion is achieved by some contact points called focal adhesions. Because focal adhesions were distributed randomly, a trial to control the positions of focal adhesion with a specific order may cause interesting effects like as cytoskeleton rearrangement, which may induce and transfer new signals to the nucleus.

Size-controllable quartz nanostructure for signal enhancement of DNA chip.

A mask-free, cost-effective dry-etching method for the fabrication of height- and spacing-controlled, pillar-like nanostructures was established in order to detect DNA molecules. The height and spacing of the quartz nanostructure were regulated by successive O(2) and CF(4) reactive ion etching times. The height and spacing of the nanostructures were tuned between 118 and 269 nm and between 107 and 161 nm, respectively.

Electrically-driven hydrogel actuators in microfluidic channels: fabrication, characterization, and biological application.

The utility of electro-responsive smart materials has been limited by bubble generation (hydrolysis) during application of electrical fields and by biocompatibility issues. Here we describe the design of a device that overcomes these limitations by combining material properties, new design concepts, and microtechnology. 4-hydroxybutyl acrylate (4-HBA) was used as a backbone hydrogel material, and its actuating behavior, bending force, and elasticity were extensively characterized as a function of size and acrylic acid concentration.

Nanostructure-dependent water-droplet adhesiveness change in superhydrophobic anodic aluminum oxide surfaces: from highly adhesive to self-cleanable.

Water-droplet adhesiveness was freely controlled on a single platform of superhydrophobic anodized aluminum oxide (AAO) within the range from highly adhesive to self-cleanable. Changing the structure from nanopore to nanopillar arrays at the surface caused a dramatic increase in the receding angle and a decrease in the hysteresis of water contact angles. The presence of dead-end nanopores but not through nanoholes was recognized as one of the main causes of the adhesiveness of superhydrophobic surfaces.

In vitro response of primary human bone marrow stromal cells to recombinant human bone morphogenic protein-2 in the early and late stages of osteoblast differentiation.

A number of factors must be added to human bone marrow stromal cells (hBMSCs) in vitro to induce osteogenesis, including ascorbic acid (AA), beta-glycerophosphate (GP), and dexamethasone (Dex). Bone morphogenic protein (BMP)-2 is an osteoinductive factor that can commit stromal cells to differentiate into osteoblasts. However, it is still not clear whether the addition of BMP-2 alone in vitro can induce hBMSCs to complete osteoblast differentiation, resulting in matrix mineralization.

Synthesis and characterization of matrix metalloprotease sensitive-low molecular weight hyaluronic acid based hydrogels.

Hyaluronic acid is a naturally derived glycosaminoglycan (GAG) involved in biological processes. A low molecular weight hyaluronic acid (50 kDa)-based hydrogel was synthesized using acrylated hyaluronic acid. Matrix metalloproteinase (MMP) sensitive hyaluronic acid-based hydrogels were prepared by conjugation with two different peptides: cell adhesion peptides containing integrin binding domains (Arg-Gly-Asp: RGD) and a cross-linker with MMP degradable peptides to mimic the remodeling characteristics of natural extracellular matrices (ECMs) by cell-derived MMPs.

Effects of cross-linking molecular weights in a hyaluronic acid-poly(ethylene oxide) hydrogel network on its properties.

We examined the effects of cross-linking molecular weights on the properties of a hyaluronic acid (HA)-poly(ethylene oxide) (PEO) hydrogel. Swelling behaviors, mechanical strength and rheological behaviors of the HA-PEO hydrogel were evaluated by employing different cross-linking molecular weights (100 kDa and 1.63 mDa) of the HAs in the hydrogel networks.

Characterization of low-molecular-weight hyaluronic acid-based hydrogel and differential stem cell responses in the hydrogel microenvironments.

Hyaluronic acid is a natural glycosaminoglycan involved in biological processes. Low-molecular-weight hyaluronic acid (10 and 50 kDa)-based hydrogel was synthesized using derivatized hyaluronic acid. Hyaluronic acid was acrylated by two steps: (1) introduction of an amine group using adipic acid dihydrazide, and (2) acrylation by N-acryloxysuccinimide.

Immobilization of fibronectin onto a large area nanoimprinted polystyrene patterns.

A well known fibrous protein, fibronectin was successfully immobilized onto well-fabricated nanopatterns of polystyrene (PS) substrates. The nanopatterns with finely-defined physical dimensions were obtained by nanoimprinting lithography (NIL) using anodized aluminum oxide (AAO) molds of which the pore sizes were controlled in nanometer scale; 45 nm, 250 nm and 410 nm for the widths and 110 nm and 500 nm for the pitches. Discrete changes of the surface images before and after the protein-adsorption on the patterns were demonstrated by scanning electron microscope (SEM), and the effect of the patterned features on the immobilization has been investigated and discussed.

"On the fly" continuous generation of alginate fibers using a microfluidic device.

In this paper, we introduce a new continuous production technique of calcium alginate fibers with a microfluidic platform similar to a spider in nature. We have used a poly(dimethylsiloxane) (PDMS) microfluidic device embedded capillary glass pipet as the apparatus for fiber generation. As a sample flow, we introduced a sodium alginate solution, and, as a sheath flow, a CaCl2 solution was introduced.