The use of molecular fluorescent markers to monitor absorption and distribution of xenobiotics in a silkworm model.

The fate of xenobiotics in living organisms is determined by their in vivo absorption, distribution, metabolism and excretion. A convenient and scalable animal model of these biological processes is thus highly beneficial in understanding the effects of xenobiotics. Here we present a silkworm model to investigate the molecular properties-directed absorption, distribution and excretion of fluorescent compounds as model xenobiotics through introducing the compounds into the silkworm's diet and monitoring the resulting color and fluorescence in the silkworm's body. The efficient uptake of xenobiotics into silk has been further studied through quantitative analysis of the intrinsically colored and highly luminescent silk secreted by silkworm. Our findings provide first-hand insights to better understand the molecular properties that allow specific materials to be incorporated into silk while it is being produced in the silk gland. The use of resulting luminescent silk as scaffold for tissue engineering application has been demonstrated to clearly reveal the interaction of silk with cells. Furthermore, this new development also paves a way to produce various functional silk embedded with stimuli-sensitive dyes or drugs as novel biomaterials for in vivo applications.