Design of a liver tissue biosensor

Summary form only given. The threat of chemical and biological attack is becoming increasingly more likely. Since the liver metabolizes xenobiotic species, construction of a liver tissue based biosensor allows the detection of a wide range of harmful agents by detecting physiological changes in cultured liver cells. Previously, the development of such technology has been limited since traditional 2D culturing methods lead to dedifferentiation and loss of hepatic functions within hours to days. By recreating a 3D culture environment similar to the acinus in the liver, maintenance of differentiated hepatic functions such as albumin secretion, urea synthesis and cytochrome p450 1A1 production has been demonstrated for culture periods over 14 days. Measurement of cytochrome p450 1A1 through ethoxyresorufin dealkylation (EROD) was adapted for use as a diagnostic to optically assess toxicity of probe compounds. Detection by both spectroscopy and 2-photon microscopy was developed to allow temporal as well morphological exploration of toxicity. These methods were used to successfully detect both aflatoxin B1, and microcystin LR. For microcystin, a five fold decrease in EROD intensity was observed within 12 hours. For aflatoxin toxicity was sensed by 15 hours for doses as low as 12 nM. Since each of these compounds act through different biological mechanisms, these results show that our liver tissue biosensor can be used to sense a range of different classes of toxins.