Multiphenotypic whole-cell sensor for viability screening.

Here, we describe the fabrication of whole mammalian cell biosensors for the optical monitoring of cell viability. Three phenotypes were examined for their response to the addition of two model chemotoxins: sodium hypochlorite and sodium azide, and one model biotoxin, concanavalin A. Two sensing platforms containing cells, hydrogel microspheres, or hydrogel arrays, were also explored.

Microreactor microfluidic systems with human microsomes and hepatocytes for use in metabolite studies.

In the area of drug discovery, high-speed synthesis has increased the number of drug candidates produced. These potential drugs need to be evaluated for their adsorption, distribution, metabolism, elimination, and toxicology (ADMET) properties as early in the drug development stage as possible. Previously, a potential drug's ADMET properties have been found out by using monolayer cell cultures and live animals.

Cryopreservation of cell-containing poly(ethylene) glycol hydrogel microarrays.

Here we describe the fabrication and preservation of mammalian cell-containing hydrogel microarrays that have potential applications in drug screening and pathogen detection. Hydrogel microstructures containing murine fibroblasts were fabricated on silicon substrates and subjected to a "stage-down" freezing process. The percent viability of both immortal and primary embryonic murine fibroblast cells within the gels was determined at various stages in the freezing process, showing that cells entrapped in hydrogel microstructures remained viable throughout the process.

Hepatocyte viability and protein expression within hydrogel microstructures.

Poly(ethylene) glycol (PEG) hydrogels have been successfully used to entrap mammalian cells for potential high throughput drug screening and biosensing applications. To determine the influence of PEG composition on the production of cellular protein, mammalian hepatocytes were maintained in PEG hydrogels for 7 days. Total cell viability, total protein production, and the production of two specific proteins, albumin and fibronectin, were monitored.

A novel single-step fabrication technique to create heterogeneous poly(ethylene glycol) hydrogel microstructures containing multiple phenotypes of mammalian cells.

In this study, a novel method for the one-step fabrication of stacked hydrogel microstructures using a microfluidic mold is presented. The fabrication of these structures takes advantage of the laminar flow regime in microfluidic devices, limiting the mixing of polymer precursor solutions. To create multilayered hydrogel structures, microfluidic devices were rotated 90 degrees from the traditional xy axes and sealed with a cover slip.

Molding of hydrogel microstructures to create multiphenotype cell microarrays.

The fabrication of mammalian cell-containing poly(ethylene glycol) (PEG) hydrogel microstructures on glass and silicon substrates is described. Using photoreaction injection molding in poly(dimethylsiloxane) microfluidic channels, three-dimensional hydrogel microstructures encapsulating cells (fibroblasts, hepatocytes, macrophage) were fabricated with cells uniformly distributed to each hydrogel microstructure, and the number of cells in each hydrogel microstructure was controlled by changing the cell density of the precursor solution. PEG hydrogels were modified using an Arg-Gly-Asp (RGD) peptide sequence, with the incorporation of RGD into the hydrogel matrix promoting the spreading of encapsulated fibroblasts over a 24-h period in culture.

The effect of dissolved oxygen (DO) concentration on the glycosylation of recombinant protein produced by the insect cell-baculovirus expression system.

The effect of dissolved oxygen concentration on human secreted alkaline phosphatase (SEAP) glycosylation by the insect cell-baculovirus expression system was investigated in a well-controlled bioreactor. Oligomannose-type N-linked glycans (i.e.