Characterization of Drosophila embryos immobilized by fluidic microassembly

A technique for positioning and immobilization of Drosophila embryos in 2-D arrays for use in high throughput microinjection experiments has been characterized. The method is based on fluidic microassembly and immobilization yield, the number of misplaced embryos, and adhesion force of the embryos have been measured for samples with two different pad geomtries. For samples with 250 /spl mu/m/spl times/400 /spl mu/m sized pads an immobilization yield of 85% was achieved. The adhesion force of the embryos was estimated at 36 /spl mu/N/spl plusmn/22 /spl mu/N. A substantial amount of clustering was, however, observed. By reducing the pad size to 200 /spl mu/m/spl times/200 /spl mu/m and changing the pad pitch the number of misplaced embryos was reduced to less then 5%. The immobilization yield was, however, lower for these samples. The adhesion force of embryos immobilized at the smaller pads was estimated at 14 /spl mu/N/spl plusmn/5.5 /spl mu/N.