embosser at an elevated temperature also since dry etch is performed to etch silicon ridges are produced on the sidewalls of the channels to smooth the ridges the channels are coated with a thin layer of teflon in some devices made in pmma the silicon wafer may break after embossing even after coating with teflon some small pieces of broken silicon are found in the channels the above method works in the fabrication of design one but design two is more difficult to produce nonetheless pmma is a possible substrate as are other materials such as glass transparencies other polymers etc in design one with a flow rate 2 u03bcl minute o d 0 40 and number of dilutions of the initial cell solution 1 10 3 the following results were obtained in one embodiment shrimp alkaline phosphatase activity loss is measured in microchannels of design one it is similar to the embodiment for the horseradish peroxidase assay only sap is known to be very heat labile a 200 mw laser 980 nm wavelength laser was used in design 1 in pdms with varying flow rates exposure of sap molecules to laser beam was controlled by varying flow rates set up a two fold dilution series with 100 u03bcl of assay buffer in tube 1 and 50 u03bcl in next 6 tubes add 3 u03bcl enzyme to tube 1 and serially dilute 50 u03bcl into 50 u03bcl into 50 u03bcl etc add 10 u03bcl of tube 5 to 1 ml of assay buffer put the solution of step 3 into.