Abstract: The invention relates to a method for linking two adjacent plastic work pieces (2, 3). The inventive method is characterized in that the intended contact zone (K) of at least one of the two work pieces (2) with which the latter adjoins to the other work piece (3) is at least partially subjected to a high-energy radiation to such an extent that the glass transition temperature is reduced in a marginal zone (R). The two work pieces (2, 3) are brought in the desired position relative to each other. For establishing the connection of the two work pieces (2, 3) at least the marginal zone (R) modified by the previous radiation process is heated at least in its surface area to a temperature that is higher than the glass transition temperature of the marginal zone (R) modified by the radiation process but lower than the glass transition temperature of the zones of the work pieces (2, 3) that have not been modified.

Abstract: Microfluidic devices are provided having units of 8-fold symmetry comprising 8 assay units, where a reservoir provides a common component to 8 assay units. The units can be compactly formed in a substrate to provide the ability to perform a large number of assays within a small area. The microfluidic devices find use in operations, such as assays, DNA sequence detection, etc. Various formats can be used to have the microfluidic device interrelate with microtiter well plates. Methods are provided for monitoring the flow rates/velocities of assay components and streams for comparison of results in different assay units and/or to modify the conditions to change the flow rates in particular channels.

Abstract: Compositions and methods are provided for performing capillary electrophoresis using a composition comprising in combination in an aqueous buffered medium a coating polymer and a sieving polymer, where the sieving polymer is more hydrophilic than the coating polymer and is present in greater amount. Of particular interest are uncrosslinked acrylamide polymer mixtures for coating plastic channels and providing sieving for performing DNA separations in microfluidic devices. Polyacrylamide or N,N-dimethyl acrylamide is used with a N,N-dialkyl acrylamide copolymer, either separately or together for sieving and coating, serving as the medium in capillary electrophoresis DNA separations.