| Advanced Point-of-Care (POC) biosensors are able to reduce the time, costs, and sample volumes of metabolic analysis for diagnostic and disease management purposes. Bioluminescent-based analysis is a highly sensitive and specific analytical method with a large detection range, but has not been used in commercial POC biosensors. The specificity is provided by analyte specific reactions coupled to bioluminescent reactions which produce light proportional the analyte concentration. Bioluminescent analytical assays, in a miniaturized and stable format, can measure microMolar concentrations in microliter sample volumes.; A prototype bioluminescence-based sensor, or "ChemChip," was built with a wicking membrane for sample delivery to an array of lyophilized bioluminescent assays in 140 nL clear bottom wells. A CCD camera was used to simultaneously measure bioluminescent signals from assays specific to ATP, NADH, galactose, and lactate.; During the development of the ChemChip, a novel rapid prototyping method called "Xurography" which means razor writing in Greek, was developed for making microstructures as small as 25 mum by cutting adhesive backed film with a knife plotter. A unique alignment method was developed to build multilayered microfluidic elements and systems.; Xurography enabled a more complicated and functional bioluminescent sensor called the "ChemCD" to be developed. In addition to aliquoting 200 nL samples from a 15 muL sample into separate reaction wells containing lyophilized bioluminescent reagents, the ChemCD can also separate and aliquot plasma samples from whole blood, by controlled centrifugal force. The reaction wells had optical enhancements to improve light collection for greater sensitivity. Bioluminescence-based assays for ATP, creatinine, galactose, and glucose were all tested simultaneously on the ChemCD.; The ChemChip and ChemCD could be convenient to operate in POC and home environments. Such devices could likely evolve to measure hundreds of different metabolites in submicroMolar and milliMolar ranges from 1-100 muL biofluid samples. They could also include customized comprehensive diagnostic panels for basic research, clinical research, and for personal disease and health management. These systems would provide rapid results, facilitate patient empowerment, and reduce health care costs. |
