we have developed an improved vapor - phase deposition method and apparatus for the application of layers and coatings on various substrates . the method and apparatus are useful in the fabrication of biotechnologically functional devices , bio - mems devices , and in the fabrication of microfluidic devices for biological applications . in one important embodiment , oxide coatings providing hydrophilicity or oxide / polyethylene glycol coatings providing hydrophilicity can be deposited by the present method , over the interior surfaces of small wells in a plastic micro - plate in order to increase the hydrophilicity of these wells . filling these channels with a precise amount of liquid consistently can be very difficult . this prevents a water - based sample from beading up and creating bubbles , so that well can fill accurately and completely , and alleviates spillage into other wells which causes contamination .