Inkjet micropatterning through horseradish peroxidase-mediated hydrogelation for controlled cell immobilization and microtissue fabrication.

A simple fabrication method for cell micropatterns on hydrogel substrates was developed using an inkjet printing system that induced hydrogel micropatterns. The hydrogel micropatterns were created from inks resulting in cell-adhesive and non-cell-adhesive printed regions by horseradish peroxidase-catalyzed reaction onto non-cell-adhesive and cell-adhesive hydrogel substrates, respectively, to obtain the cell micropatterns. Cell-adhesive and non-cell-adhesive regions were obtained from gelatin and alginate derivatives, respectively.

Gelatin/Hyaluronic Acid Content in Hydrogels Obtained through Blue Light-Induced Gelation Affects Hydrogel Properties and Adipose Stem Cell Behaviors.

Composite hydrogels of hyaluronic acid and gelatin attract great attention in biomedical fields. In particular, the composite hydrogels obtained through processes that are mild for cells are useful in tissue engineering. In this study, hyaluronic acid/gelatin composite hydrogels obtained through a blue light-induced gelation that is mild for mammalian cells were studied for the effect of the content of each polymer in the precursor solution on gelation, properties of resultant hydrogels, and behaviors of human adipose stem cells laden in the hydrogels.

Horseradish peroxidase-catalyzed hydrogelation consuming enzyme-produced hydrogen peroxide in the presence of reducing sugars.

In the present work, three kinds of reducing sugars: glucose, galactose, and mannose, are applied to horseradish peroxidase (HRP)-catalyzed hydrogelation of an aqueous solution containing natural polymers modified with phenolic hydroxyl moieties. In this system, HRP consumes hydrogen peroxide that was generated from the oxidation of thiol groups in HRP in the presence of reducing sugars. Herein, we highlight the versatility of applicable sugar types and the controllable hydrogel properties.

Characterization of encapsulated cells within hyaluronic acid and alginate microcapsules produced via horseradish peroxidase-catalyzed crosslinking.

Hydrogel microcapsules having the ability to promote cell adhesion and proliferation are a useful tool for fabricating tissue in vitro. The present study explored the effects of two anionic polysaccharide hydrogel membranes which have an impact on the adhesiveness, morphology and growth of cells. Microcapsules were made by coating a cell-laden gelatin microparticle with a hydrogel membrane produced from modified hyaluronic acid or alginate possessing phenolic hydroxyl moieties (HA-Ph or Alg-Ph respectively) via a horseradish peroxidase-catalyzed crosslinking reaction.

Inducing flocculation of non-floc-forming Escherichia coli cells.

The present article reviews several approaches for inducing flocculation of Escherichia coli cells. The common industrially used bacterium E. coli does not naturally have floc-forming ability.

Peroxidase-catalyzed microextrusion bioprinting of cell-laden hydrogel constructs in vaporized ppm-level hydrogen peroxide.

Hydrogels were prepared by contacting air containing 10-50 ppm HO with an aqueous solution containing polymer(s) possessing phenolic hydroxyl (Ph) moieties (polymer-Ph) and horseradish peroxidase (HRP). In this system, HRP catalyzes cross-linking of the Ph moieties by consuming HO diffused from the air. The hydrogelation rate and mechanical properties of the resultant hydrogels can be tuned by controlling the HO concentration in air, the exposure time of the air containing HO to the solution containing polymer-Phs and HRP, and the HRP concentration.

Visible Light-Induced Hydrogelation of an Alginate Derivative and Application to Stereolithographic Bioprinting Using a Visible Light Projector and Acid Red.

Visible light-induced hydrogelation is attractive for various biomedical applications. In this study, hydrogels of alginate with phenolic hydroxyl groups (Alg-Ph) were obtained by irradiating a solution containing the polymer, ruthenium II trisbipyridyl chloride ([Ru(bpy)]) and sodium persulfate (SPS), with visible light. The hydrogelation kinetics and the mechanical properties of the resultant hydrogels were tunable by controlling the intensity of the light and the concentrations of [Ru(bpy)] and SPS.

Drop-On-Drop Multimaterial 3D Bioprinting Realized by Peroxidase-Mediated Cross-Linking.

A cytocompatible inkjet bioprinting approach that enables the use of a variety of bioinks to produce hydrogels with a wide range of characteristics is developed. Stabilization of bioinks is caused by horseradish peroxidase (HRP)-catalyzed cross-linking consuming hydrogen peroxide (H O ). 3D cell-laden hydrogels are fabricated by the sequential dropping of a bioink containing polymer(s) cross-linkable through the enzymatic reaction and H O onto droplets of another bioink containing the polymer, HRP, and cells.

Differentiation potential of human adipose stem cells bioprinted with hyaluronic acid/gelatin-based bioink through microextrusion and visible light-initiated crosslinking.

Bioprinting has a great potential to fabricate three-dimensional (3D) functional tissues and organs. In particular, the technique enables fabrication of 3D constructs containing stem cells while maintaining cell proliferation and differentiation abilities, which is believed to be promising in the fields of tissue engineering and regenerative medicine. We aimed to demonstrate the utility of the bioprinting technique to create hydrogel constructs consisting of hyaluronic acid (HA) and gelatin derivatives through irradiation by visible light to fabricate 3D constructs containing human adipose stem cells (hADSCs).

Displaying a recombinant protein on flocs self-produced by Escherichia coli through fused expression with elongation factor Ts.

The utility of engineering flocculation is wildly recognized in applied and environmental microbiology. We previously reported self-produced flocculation of Escherichia coli cells by overexpressing the native bcsB gene that encodes a component of the cellulose synthesis pathway. Further experiments clarified that the spontaneous E.

Quantitative Evaluation of Recombinant Protein Packaged into Outer Membrane Vesicles of Escherichia coli Cells.

Outer membrane vesicles (OMVs) are spherical bilayered proteolipids released from the cell surfaces of bacteria, which have gained traction in the biotechnology fields. Bacterial cellular machinery can be genetically engineered to produce and package heterologous enzymes into OMVs, producing nanocarriers and nanoparticle catalysts. However, the productivity or efficiency of packaging the target protein into OMVs has not been quantitatively evaluated.

Cell-laden microgel prepared using a biocompatible aqueous two-phase strategy.

Microfluidic methods are frequently used to produce cell-laden microgels for various biomedical purposes. Such microfluidic methods generally employ oil-water systems. The poor distribution of crosslinking reagents in the oil phase limits the available gelation strategies.

Fabrication of single and bundled filament-like tissues using biodegradable hyaluronic acid-based hollow hydrogel fibers.

Hydrogel fibers with biodegradable and biocompatible features are useful for the fabrication of filament-like tissues. We developed cell-laden hyaluronic acid (HA)-based hollow hydrogel fibers to create single and bundled filament-like tissues. The cell-laden fibers were fabricated by crosslinking phenolic-substituted hyaluronic acid (HA-Ph) in an aqueous solution containing cells through a horseradish peroxidase (HRP)-catalyzed reaction in the presence of catalase by extruding the solution in ambient flow of an aqueous solution containing HO.

Cytocompatible Enzymatic Hydrogelation Mediated by Glucose and Cysteine Residues.

Hydrogels were obtained from aqueous solution containing polymer(s) possessing phenolic hydroxyl moieties through horseradish peroxidase (HRP)-catalyzed reaction without direct addition of HO. In this hydrogelation process, HO was generated from HRP and glucose contained in the aqueous solution, that is, HRP functioned not only as a catalyst, but also as a source of HO. The gelation time and mechanical properties of the resultant hydrogel could be altered by changing the concentrations of HRP and glucose.

Impact of immobilizing of low molecular weight hyaluronic acid within gelatin-based hydrogel through enzymatic reaction on behavior of enclosed endothelial cells.

The hydrogels having the ability to promote migration and morphogenesis of endothelial cells (ECs) are useful for fabricating vascularized dense tissues in vitro. The present study explores the immobilization of low molecular weight hyaluronic acid (LMWHA) derivative within gelatin-based hydrogel to stimulate migration of ECs. The LMWHA derivative possessing phenolic hydroxyl moieties (LMWHA-Ph) was bound to gelatin-based derivative hydrogel through the horseradish peroxidase-catalyzed reaction.

Inkjetting Plus Peroxidase-Mediated Hydrogelation Produces Cell-Laden, Cell-Sized Particles with Suitable Characters for Individual Applications.

The authors report a method to prepare cell-laden, cell-sized microparticles from various materials suitable for individual applications. The method includes a piezoelectric inkjetting technology and a horseradish peroxidase (HRP)-catalyzed crosslinking reaction. The piezoelectric inkjetting technology enables production of cell-laden, cell-sized (20-60 μm) droplets from a polymer aqueous solution.

Deletion of degQ gene enhances outer membrane vesicle production of Shewanella oneidensis cells.

Shewanella oneidensis is a Gram-negative facultative anaerobe that can use a wide variety of terminal electron acceptors for anaerobic respiration. In this study, S. oneidensis degQ gene, encoding a putative periplasmic serine protease, was cloned and expressed.

Antibiofilm effect of warfarin on biofilm formation of Escherichia coli promoted by antimicrobial treatment.

Enhancement of microbial biofilm formation by low antimicrobial doses is a critical problem in the medical field. The objective of this study was to propose a new drug candidate against the biofilm formation promoted by subinhibitory dose of antimicrobials. To determine the effect on biofilm formation of Escherichia coli, a subinhibitory concentration of lactoferrin (LF), a milk protein involved in a broad range of biological properties including antimicrobial action, or ampicillin (AMP), a typical antibiotic, was added to an E.

5,5-Dithiobis(2-nitrobenzoic acid) pyrene derivative-carbon nanotube electrodes for NADH electrooxidation and oriented immobilization of multicopper oxidases for the development of glucose/O biofuel cells.

We report the functionalization of multi-walled carbon nanotubes (MWCNTs) electrodes by a bifunctional nitroaromatic molecule accomplished via π-π interactions of a pyrene derivative. DTNB (5,5'-dithiobis(2-nitrobenzoic acid)) has the particularity to possess both electroactivable nitro groups and negatively charged carboxylic groups. The integration of the DTNB-modified MWCNTs was evaluated for different bioelectrocatalytic systems.

Anchoring PEG-oleate to cell membranes stimulates reactive oxygen species production.

Polyethylene glycol (PEG) derivatives possessing oleyl and reactive groups for conjugating functional substrates, such as proteins and quantum dots, are useful materials for cell-surface engineering and cell immobilization onto substrates. The reagent is known as a biocompatible anchor for cell membranes (BAM). Here, BAM-anchoring on cell membranes is reported to stimulate reactive oxygen species (ROS) production in those cells.

Enzymatically-gellable galactosylated chitosan: Hydrogel characteristics and hepatic cell behavior.

The influence of contents of galactose and phenolic hydroxyl (Ph) groups incorporated into chitosan was investigated on characteristics of the chitosan derivatives and the resultant gels as well as HepG2 cell attachment and growth behaviors. Introduction of galactose groups increased the solubility of the chitosan derivatives. The gelation time decreased with increasing content of Ph groups in the chitosan derivatives.

Engineering tissues with a perfusable vessel-like network using endothelialized alginate hydrogel fiber and spheroid-enclosing microcapsules.

Development of the technique for constructing an internal perfusable vascular network is a challenging issue in fabrication of dense three-dimensional tissues in vitro. Here, we report a method for realizing it. We assembled small tissue (about 200 μm in diameter)-enclosing hydrogel microcapsules and a single hydrogel fiber, both covered with human vascular endothelial cells in a collagen gel.

Recent developments in ex vivo platelet production.

The platelet is a component of blood that functions to initiate blood clotting. Abnormal platelet count and function can lead to a life-threatening condition caused by excessive bleeding. At present, platelet supply for transfusion can be obtained only from platelet donation.

Cryopreservation of a small number of human sperm using enzymatically fabricated, hollow hyaluronan microcapsules handled by conventional ICSI procedures.

Purpose: We investigated whether enzymatically fabricated hyaluronan (HA) microcapsules were feasible for use in the cryopreservation of a small number of sperm.

Methods: HA microcapsules were fabricated using a system of water-immiscible fluid under laminar flow. Three sperm were injected into a hollow HA microcapsule using a micromanipulator.

Propagation of human iPS cells in alginate-based microcapsules prepared using reactions catalyzed by horseradish peroxidase and catalase.

Cell encapsulation has been investigated as a bioproduction system in the biomedical and pharmaceutical fields. We encaps-ulated human induced pluripotent stem (hiPS) cells in duplex microcapsules prepared from an alginate derivative possessing phenolic hydroxyl moieties, in a single-step procedure based on two competing enzymatic reactions catalyzed by horseradish peroxidase (HRP) and catalase. The encapsulated cells maintained 91.