Improvements in LED-based fluorescence analysis systems

This paper presents results from an electronic interface that significantly improves the stability, power output, and spectral flexibility of light emitting diode (LED)-based systems used to excite fluorescence or other forms of luminescence. LEDs are an attractive alternative to conventional white-light sources used in fluorescence analysis because of reduced power of operation, enhanced modularity, reduced optical loss, fewer imaging artifacts, and increased flexibility in spectral control without the need for high overhead optics. Drawbacks of previously presented LED-based systems include insufficient light output, instability (poor lifetime), and limited flexibility in broadband spectral output. The LED-array-based system here presents, up to a 93% improvement in stability over other LED-based systems, up to 100-fold increase in light output over single LED systems, and millions of possible combinations of spectral output (as compared to a 1–10 possible spectral outputs with one to two LED array-based systems). These benefits over previous LED-based systems are achieved at a reduction in power, space, and cost of at least one order of magnitude over conventional white-light source-based systems. Used in conjunction with appropriate optics, this electronic interface provides a highly competitive, portable (small footprint) alternative to conventional fluorometer designs.