Spatiotemporally controlled contraction of micropatterned skeletal muscle cells on a hydrogel sheet.

We have developed gel sheet-supported C(2)C(12) myotube micropatterns and combined them with a microelectrode array chip to afford a skeletal muscle cell-based bioassay system. Myotube line patterns cultured on a glass substrate were transferred with 100% efficiency to the surface of fibrin gel sheets. The contractile behavior of each myotube line pattern on the gel was individually controlled by localized electrical stimulation using microelectrode arrays that had been previously modified with electropolymerized poly(3,4-ethylenedioxythiophene) (PEDOT).

A scalable controlled-release device for transscleral drug delivery to the retina.

A transscleral drug-delivery device, designed for the administration of protein-type drugs, that consists of a drug reservoir covered with a controlled-release membrane was manufactured and tested. The controlled-release membrane is made of photopolymerized polyethylene glycol dimethacrylate (PEGDM) that contains interconnected collagen microparticles (COLs), which are the routes for drug permeation. The results showed that the release of 40-kDa FITC-dextran (FD40) was dependent on the COL concentration, which indicated that FD40 travelled through the membrane-embedded COLs.

Directing the flow of medium in controlled cocultures of HeLa cells and human umbilical vein endothelial cells with a microfluidic device.

A microfluidic device was integrated with a controlled coculture system of HeLa cells and human umbilical vein endothelial cells (HUVECs). This integrated assembly allowed control of the direction of flow of medium (along with signaling factors secreted from cells) across the cultured cells. We grew HeLa cells and HUVECs to confluency on separate substrates and then joined the two substrates.

Preparation and characterization of collagen microspheres for sustained release of VEGF.

In this study, we prepared injectable collagen microspheres for the sustained delivery of recombinant human vascular endothelial growth factor (rhVEGF) for tissue engineering. Collagen solution was formed into microspheres under a water-in-oil emulsion condition, followed by crosslinking with water-soluble carbodiimide. Various sizes of collagen microspheres in the range of 1-30 mum diameters could be obtained by controlling the surfactant concentration and rotating speed of the emulsified mixture.

Transfer of two-dimensional patterns of human umbilical vein endothelial cells into fibrin gels to facilitate vessel formation.

Two-dimensional cell patterns prepared on substrate surfaces by an electrochemical-based biolithography method have been transferred into fibrin gels prepared in situ. Line patterns of human umbilical vein endothelial cells (HUVECs) in the gel that was strained after the transfer formed a linear vessel-like structure within 8 days.

Micropatterning contractile C2C12 myotubes embedded in a fibrin gel.

Contractile C(2)C(12) myotube line patterns embedded in a fibrin gel have been developed to afford a physiologically relevant and stable bioassay system. The C(2)C(12) myotube/fibrin gel system was prepared by transferring a myotube monolayer from a glass substrate to a fibrin gel while retaining the original line patterns of myotubes. To endow the myotubes with contractile activity, a series of electrical pulses was applied through a pair of carbon electrodes placed at either side of a fibrin gel separately.

Controlled cocultures of HeLa cells and human umbilical vein endothelial cells on detachable substrates.

We investigated the interactions between HeLa cells and human umbilical vein endothelial cells (HUVECs) by monitoring their movements in a controllable coculture system. Two complementary, detachable, cell-substrates, one of polystyrene (PS) and the other of poly(dimethylsiloxane) (PDMS), were fabricated by replica molding. Coculturing was started by mechanically assembling two complementary substrates.

Generation of patterned cell co-cultures in silicone tubing using a microelectrode technique and electrostatic assembly.

We report a method for producing patterned cell adhesion inside silicone tubing. A platinum needle microelectrode was inserted through the wall of the tubing and an oxidizing agent electrochemically generated at the inserted electrode. This agent caused local detachment of the anti-biofouling heparin layer from the inner surface of the tubing.

Stepwise formation of patterned cell co-cultures in silicone tubing.

Here, we describe a method for producing patterned cell adhesion inside silicone tubing. A platinum (Pt) needle microelectrode was inserted through the wall of the tubing and an oxidizing agent electrochemically generated at the inserted electrode. This agent caused local detachment of the anti-biofouling heparin layer from the inner surface of the tubing.

Patterning cellular motility using an electrochemical technique and a geometrically confined environment.

We describe herein a method for controlling the pattern of permissible cell migration and proliferation on a substrate in time and space. Using this method, a confluent monolayer of cells that is confined within a defined region is released into a neighboring region. Incorporated into the method is an electrochemical technique that uses a scanning microelectrode to draw regions on the surface of the system that thereafter can support cell migration and growth.