The impact of temperature on protein expression in fruit flies can now be studied using a microfluidic device thanks to chemists from the US.

Rustem Ismagilov and colleagues at the University of Chicago controlled the temperature across fly embryos so that one half of the embryo was cooler than the other. They used multi-stream laminar flow to control the local temperature of live Drosophila melanogaster  fruit fly embryos and a Y-shaped tube device with the embryo fixed at the junction point. Two flowing streams at different temperatures were then employed to control the temperature of each half of the embryo. The change in temperature was found to locally affect protein expression.

'Biochemical processes are sensitive to small differences in environmental temperature,' said Ismagilov. The rates of protein expression were disrupted depending on which area of flow a given part of the embryo was exposed to. The temperature affected the order in which proteins were expressed within the Drosophila embryo. This was visible on the embryo itself as a striped or banded patterning following staining for the protein in question. The bands formed on the warm side of the embryo first.

The laminar flow was visualised by labelling the streams with ink or fluorescent microspheres to verify the existence of a temperature gradient. The heat difference was confirmed using a suspension of liquid crystals, which responded to changes in temperature.

'The microfluidic platform could prove useful in understanding the dynamics of biochemical methods as they respond to changes in temperature' said Ismagilov.

Michael J Spencelayh