A NOVEL FABRICATION PROCEDURE FOR THE PREPARATION OF POLYMETHYL METHACRYLATE LAB-ON-A-CHIP SUBSTRATES

Modification of a minicomputer numerical controller with a low cost diode laser for fabrication of polymethyl methacrylate chips has been demonstrated. The maximum power of the diode laser was 5W at 808nm. The scanning speed was 1.0-10.0mms(-1) by the movement of x and y stages. The patterns of microchannels on the chip were designed using drawing software and then applied to software that controlled the operation of the controller. The parameters that affected the channel depth, width, and smoothness were studied by varying the laser power and speed of polymethyl methacrylate sheets with surface area of 4.0x6.0cm(2) and thickness of 0.1cm. The optimum conditions were used to fabricate microchannels on each sheet giving different depths and widths over the range of 74 mu m to 554 mu m and 147 mu m to 393 mu m, respectively. The most appropriate conditions for polymethyl methacrylate chip fabrication were 5W and 3mms(-1) for the laser diode power and the speed, respectively. The optimal dimensions of the microchannel on the polymethyl methacrylate sheet were 226 mu m in width and 202 mu m in depth based on sensitivity, reproducibility, and low background signals. The microchannels were sealed with a polymethyl methacrylate cover plate by thermal bonding. The resulting chips were tested for iron(III) determination in water based on microreverse flow analysis.