| Microfluidic chip-based analysis has progressed rapidly since the concept was introduced nearly two decades ago, offering several benefits over conventional benchtop analysis that include reduced reagent volumes and faster analysis times. Most of these benefits have been achieved using laser-induced fluorescence (LIF) detection to interrogate the microfluidic system and generate endpoint data for analysis, and LIF detection will likely continue to play a large role in the future of microfluidics, as the process of miniaturizing and integrating optical components onto and around the microchip has already begun.; The chapters that follow present advances and applications of microfluidic systems using LIF detection on microchip. This includes the development of a multicolor detection system for microchip analysis using an acousto-optic tunable filter (AOTF). This versatile and compact filter, which can be used to isolate specific user-selected wavelengths, is demonstrated in several different applications, highlighted by the first five-color genotyping analysis performed on microchip. A portable analysis system is also developed using a combination of electrokinetically-driven flow control on microchip and the detection of naturally-fluorescenng phycobiliproteins found in algae, demonstrating the utility of microchip analysis in point-of-collection applications where LIF data can provide indications of environmental change. LIF is also a powerful tool for the evaluation of new microchip technologies, and as described in the development of an alternative to electrokinetic mobilization for injecting sample on microchip. Using LIF signal from a mixture of dyes to evaluate pressure-based pumping on-chip, the ability to manipulate small volumes and perform reproducible and representative sampling is demonstrated on simple and complex devices, including the most complete micro total analysis (muTAS) system reported to date. |
