Cell-Specific Impacts of Surface Coating Composition on Extracellular Vesicle Secretion.

Biomaterial properties have recently been shown to modulate extracellular vesicle (EV) secretion and cargo; however, the effects of substrate composition on EV production remain underexplored. This study investigates the impacts of surface coatings composed of collagen I (COLI), fibronectin (FN), and poly l-lysine (PLL) on EV secretion for applications in therapeutic EV production and to further understanding of how changes in the extracellular matrix microenvironment affect EVs. EV secretion from primary bone marrow-derived mesenchymal stromal cells (BMSCs), primary adipose-derived stem cells (ASCs), HEK293 cells, NIH3T3 cells, and RAW264.

Platelet Biorheology and Mechanobiology in Thrombosis and Hemostasis: Perspectives from Multiscale Computation.

Thrombosis is the pathological clot formation under abnormal hemodynamic conditions, which can result in vascular obstruction, causing ischemic strokes and myocardial infarction. Thrombus growth under moderate to low shear (<1000 s) relies on platelet activation and coagulation. Thrombosis at elevated high shear rates (>10,000 s) is predominantly driven by unactivated platelet binding and aggregating mediated by von Willebrand factor (VWF), while platelet activation and coagulation are secondary in supporting and reinforcing the thrombus.

Osmotically Rupturing Phagosomes in Macrophages Using PNIPAM Microparticles.

The rupture of macrophage phagosomes has been implicated in various human diseases and plays a critical role in immunity. However, the mechanisms underlying this process are complex and not yet fully understood. This study describes the development of a robust engineering method for rupturing phagosomes based on a well-defined mechanism.

Engineering Human Mesenchymal Bodies in a Novel 3D-Printed Microchannel Bioreactor for Extracellular Vesicle Biogenesis.

Human Mesenchymal Stem Cells (hMSCs) and their derived products hold potential in tissue engineering and as therapeutics in a wide range of diseases. hMSCs possess the ability to aggregate into "spheroids", which has been used as a preconditioning technique to enhance their therapeutic potential by upregulating stemness, immunomodulatory capacity, and anti-inflammatory and pro-angiogenic secretome. Few studies have investigated the impact on hMSC aggregate properties stemming from dynamic and static aggregation techniques.

Specific labelling of phagosome-derived vesicles in macrophages with a membrane dye delivered with microfabricated microparticles.

Phagocytosis performed by a macrophage involves complex membrane trafficking and reorganization among various membranous cellular structures including phagosomes and vesicles derived from the phagosomes known as phagosome-derived vesicles. The present work reports on development of a technique that allows to specifically label the phagosome-derived vesicles in macrophages with a membrane dye. The technique is based on the use of microfabricated microparticles that are made of a thermosensitive nonbiodegradable polymer poly(N-isopropylacrylamide) (PNIPAM) or its derivative and contain a membrane dye 1,1'-dialkyl-3,3,3',3'-tetramethylindodicarbocyanine (DiI).

DNA Nanomachines for Identifying Cancer Biomarkers in Body Fluids and Cells.

Identifying molecular biomarkers promises to significantly improve the accuracy in cancer diagnosis at its early stage. DNA nanomachines, which are designable and switchable nanostructures made of DNA, show broad potential to detect tumor biomarkers with noninvasive, inexpensive, highly sensitive, and highly specific advantages. This Feature summarizes the recent DNA nanomachine-based platforms for the early detection of cancer biomarkers, both from body fluids and in cells.

Controlled Fabrication of DNA Molecular Templates for Formation and Measurement of Ultrathin Metal Nanostructures.

Fabrication of ultrathin metal nanostructures usually requires some combination of high-vacuum deposition and postgrowth processing, which precludes access to nanostructures of ultrasmall cross sections for most materials. DNA nanowires (NWs) are versatile insulating templates with intrinsic sub-10 nm line width. Here, we demonstrate a method of DNA template fabrication with precise control over the location and orientation of the DNA NWs.

Conjugating Micropatches to Living Cells Through Membrane Intercalation.

Existing clinical cell therapies, which rely on the use of biological functionalities of living cells, can be further enhanced by conjugating functional particles to the cells to form cell-particle complexes. Disk-shaped microparticles produced by the top-down microfabrication approach possess unique advantages for this application. However, none of the current mechanisms for conjugating the microfabricated microparticles to the cells are principally applicable to all types of cells with therapeutic potentials.

Microcontact Printing with Laser Direct Writing Carbonization for Facile Fabrication of Carbon-Based Ultrathin Disk Arrays and Ordered Holey Films.

A nanometer-thick carbon film with a highly ordered pattern structure is very useful in a variety of applications. However, its large-scale, high-throughput, and low-cost fabrication is still a great challenge. Herein, microcontact printing (µCP) and direct laser writing carbonization (DLWc) are combined to develop a novel method that enables ease of fabrication of nanometer-thick and regularly patterned carbon disk arrays (CDAs) and holey carbon films (HCFs) from a pyromellitic dianhydride-oxydianiline-based polyamic acid (PAA) solution.

Functionalization of Brain Region-specific Spheroids with Isogenic Microglia-like Cells.

Current brain spheroids or organoids derived from human induced pluripotent stem cells (hiPSCs) still lack a microglia component, the resident immune cells in the brain. The objective of this study is to engineer brain region-specific organoids from hiPSCs incorporated with isogenic microglia-like cells in order to enhance immune function. In this study, microglia-like cells were derived from hiPSCs using a simplified protocol with stage-wise growth factor induction, which expressed several phenotypic markers, including CD11b, IBA-1, CX3CR1, and P2RY12, and phagocytosed micron-size super-paramagnetic iron oxides.

Development of a microdevice-based human mesenchymal stem cell-mediated drug delivery system.

Cell-mediated drug delivery systems utilize living cells as vehicles to achieve controlled delivery of drugs. One of the systems features integrating cells with disk-shaped microparticles termed microdevices into cell-microdevice complexes that possess some unique advantages over their counterparts. Human mesenchymal stem cells (hMSCs) have been extensively studied as therapeutic cells and used as carrier cells for drug-loaded nanoparticles or other functional nanoparticles.

Cell population balance of cardiovascular spheroids derived from human induced pluripotent stem cells.

Stem cell-derived cardiomyocytes and vascular cells can be used for a variety of applications such as studying human heart development and modelling human disease in culture. In particular, protocols based on modulation of Wnt signaling were able to produce high quality of cardiomyocytes or vascular cells from human pluripotent stem cells (hPSCs). However, the mechanism behind the development of 3D cardiovascular spheroids into either vascular or cardiac cells has not been well explored.

Highly Efficient Spectrally Stable Red Perovskite Light-Emitting Diodes.

Perovskite light-emitting diodes (LEDs) have recently attracted great research interest for their narrow emissions and solution processability. Remarkable progress has been achieved in green perovskite LEDs in recent years, but not blue or red ones. Here, highly efficient and spectrally stable red perovskite LEDs with quasi-2D perovskite/poly(ethylene oxide) (PEO) composite thin films as the light-emitting layer are reported.

Single cell patterning for high throughput sub-cellular toxicity assay.

Cell population based toxicity assays cannot distinguish responses of single cells and sub-cellular organelles; while single cell assays are limited by low statistical power due to small number of cells examined. This article reports a new single cell array based toxicity assay, in which cell responses at population level, single cell level and sub-cellular level can be obtained simultaneously at high throughput. The single cell array was produced by microcontact printing and selected area cell attachment, and exposed to damaging X-ray radiation, which was followed by fluorescence imaging after staining.

Catalase-Laden Microdevices for Cell-Mediated Enzyme Delivery.

Enzymes have been used to treat various human diseases and traumas. However, the therapeutic utility of free enzymes is impeded by their short circulation time, lack of targeting ability, immunogenicity, and inability to cross biological barriers. Cell-mediated drug delivery approach offers the unique capability to overcome these limitations, but the traditional cell-mediated enzyme delivery techniques suffer from drawbacks such as risk of intracellular degradation of and low loading capacity for the payload enzyme.

Neural patterning of human induced pluripotent stem cells in 3-D cultures for studying biomolecule-directed differential cellular responses.

Introduction: Appropriate neural patterning of human induced pluripotent stem cells (hiPSCs) is critical to generate specific neural cells/tissues and even mini-brains that are physiologically relevant to model neurological diseases. However, the capacity of signaling factors that regulate 3-D neural tissue patterning in vitro and differential responses of the resulting neural populations to various biomolecules have not yet been fully understood.

Methods: By tuning neural patterning of hiPSCs with small molecules targeting sonic hedgehog (SHH) signaling, this study generated different 3-D neuronal cultures that were mainly comprised of either cortical glutamatergic neurons or motor neurons.

Asymmetric biodegradable microdevices for cell-borne drug delivery.

Use of live cells as carriers for drug-laden particulate structures possesses unique advantages for drug delivery. In this work, we report on the development of a novel type of particulate structures called microdevices for cell-borne drug delivery. The microdevices were fabricated by soft lithography with a disklike shape.

Enhanced radiation therapy with multilayer microdisks containing radiosensitizing gold nanoparticles.

A challenge of X-ray radiation therapy is that high dose X-rays at therapeutic conditions damage normal cells. This paper describes the use of gold nanoparticle-loaded multilayer microdisks to enhance X-ray radiation therapy, where each microdisk contains over 10(5) radiosensitizing nanoparticles. The microdisks are attached on cell membranes through electrostatic interaction.

Versatile surface micropatterning and functionalization enabled by microcontact printing of poly(4-aminostyrene).

Microcontact printing (μCP) of polyelectrolytes is a facile and powerful method for surface micro/nanopatterning and functionalization. Poly(4-aminostyrene) (PAS) is a polyelectrolyte that can be converted to aryldiazonium salt and exhibits pH-dependent hydrophobicity. Here we demonstrate μCP of PAS and the expansion of this technique in various directions.

Facile functionalization and assembly of live cells with microcontact-printed polymeric biomaterials.

The functionalization and assembly of live cells with microfabricated polymeric biomaterials have attracted considerable interest in recent years, but the conventional methods suffer from high cost, high complexity, long processing time or inadequate capability. The present study reports on the development of a novel method for functionalizing and assembling live cells by integrating microcontact printing of polymeric biomaterials with a temperature-sensitive sacrificial layer prepared by spin-coating. This method has been used not only to functionalize live cells with microscopic polyelectrolyte and thermoplastic structures of various sizes and shapes, but also to assemble the cells into macroscopic stripes and sheets.

Gold nanoparticle-packed microdisks for multiplex Raman labelling of cells.

Micro/nanoparticles containing densely packed gold nanoparticles (AuNPs) possess unique properties potentially useful for various biomedical applications. The micro/nanoparticles are conventionally produced by the bottom-up methods, which have limited capability for controlling the particle size, shape and structure. This article reports development of a top-down method that integrates layer-by-layer assembly and microcontact printing to fabricate disk-shaped microparticles named microdisks composed of densely packed AuNPs.

A paper indicator for triple-modality sensing of nitrite based on colorimetric assay, Raman spectroscopy, and electron paramagnetic resonance spectroscopy.

Paper indicators based on colorimetric assays are widely used for nitrite detection, but their application to liquids with strong colours is restricted. We report a novel paper indicator that allows for sensing nitrite by colorimetric assay, Raman spectroscopy, and electron paramagnetic resonance spectroscopy with non-overlapping signal wavelength ranges through non-contact means. The paper indicator was prepared by impregnating poly(4-aminostyrene), 2-naphthol and single-walled carbon nanotubes in a regular filter paper.

[Sequence analysis of LEAFY homologous gene from Dendrobium moniliforme and application for identification of medicinal Dendrobium].

The LEAFY (LFY) homologous gene of Dendrobium moniliforme (L.) Sw. was cloned by new primers which were designed based on the conservative region of known sequences of orchid LEAFY gene.

Low-cost fabrication of centimetre-scale periodic arrays of single plasmid DNA molecules.

We report the development of a low-cost method to generate a centimetre-scale periodic array of single plasmid DNA molecules of 11 kilobase pairs. The arrayed DNA molecules are amenable to enzymatic and physical manipulations.