The Design and Fabrication of Three-Chamber Microscale Cell Culture Analog Devices with Integrated Dissolved Oxygen Sensors

Abstract

Whole animal testing is an essential part in evaluating the toxicological and pharmacological profiles of chemicals and pharmaceuticals, but these experiments are expensive and cumbersome. A cell culture analog (CCA) system, when used in conjunction with a physiologically based pharmacokinetic (PBPK) model, provides an in vitro supplement to animal studies and the possibility of a human surrogate for predicting human response in clinical trials. A PBPK model mathematically simulates animal metabolism by modeling the absorption, distribution, metabolism, and elimination kinetics of a chemical in interconnected tissue compartments. A CCA uses mammalian cells cultured in interconnected chambers to physically represent the corresponding PBPK. These compartments are connected by recirculating tissue culture medium that acts as a blood surrogate. The purpose of this article is to describe the design and basic operation of the microscale manifestation of such a system. Microscale CCAs offer the potential for inexpensive, relatively high throughput evaluation of chemicals while minimizing demand for reagents and cells. Using microfabrication technology, a three-chamber ("lung"-"liver"-"other") microscale cell culture analog (µCCA) device was fabricated on a 1 in. (2.54 cm) square silicon chip. With a design flow rate of 1.76 µL/min, this µCCA device achieves approximate physiological liquidto-cell ratio and hydrodynamic shear stress while replicating the liquid residence time parameters in the PBPK model. A dissolved oxygen sensor based on collision quenching of a fluorescent ruthenium complex by oxygen molecules was integrated into the system, demonstrating the potential to integrate real-time sensors into such devices.

Chip-based liver equivalents for toxicity testing – organotypicalness versus cost-efficient high throughput

“…A system developed for pharmacokinetic and pharmacodynamic modelling by Shuler's group 54 (Fig. 2b) has been improved regarding culture format from monolayer hepatocyte cultures to 3D hydrogel supported cultures.…”

Modeling Life

“…Each compartment corresponds to a tissue or organ in the PBPK and the body. We call this approach a micro cell culture analog or ''Body-on-a-Chip'' 17,22 and was the first description of a multi-compartment cell-containing system that attempted to arrange the various ''organ'' compartments in a physiologically realistic manner.…”

“…We called the first device of this type a cell culture analog (CCA) and was described in Sweeny et al 24 We then constructed our first micro scale device, a microCCA and described it in 2004. 17 The micro scale makes it feasible to run multiple units relatively cheap.…”

“…Details of design and operation are given elsewhere. 17,22,25,28 The system has been used to determine response to naphthalene as a model toxicant. Naphthalene is not toxic itself, but activated in the liver to a reactive form, which causes cell death in other organs, such as the lung.…”

Characterization of microfluidic human epidermal keratinocyte culture

“…The use of HEK in toxicity assays (Chou et al 2002;Didier et al 1999;Monteiro-Riviere et al 2005;Rouse et al 2006;Shvedova et al 2003) makes this cell type an attractive candidate for use in microfluidic high throughput toxicity assays. Cell culture in microfluidic systems has been demonstrated by others Delamarche et al 2005;Figallo et al 2007;Flaim et al 2005;Folch and Toner 2000;Gu et al 2004;Hui and Bhatia 2007;Hung et al 2005a, Hung et al b;Kane et al 2006;Khademhosseini et al 2004;Kim et al 2006;Leclerc et al 2006a;b;Lee et al 2006;Prokop et al 2004;Raty et al 2004;Rhee et al 2005;Sin et al 2004;Song et al 2005;Toh et al 2007;Tourovskaia et al 2005;Walker et al 2002) but keratinocytes have not yet been studied at the microscale.…”