Microfluidic devices are attracting interest for point-of-care diagnostics due to their low unit cost, low reagent and sample usage, fast analysis times and portability. Fluorescence is the most widely used detection method in microfluidics due to its high sensitivity, excellent dynamic range, ease of implementation and non-invasive nature. Fluorescence detection has accordingly been widely used for the interrogation of microfluidic devices, with the majority of reports to date having used non-integrated laser excitation sources coupled with off-chip optics and photodetectors. For point-of-care applications, there is a growing need for self-contained systems which incorporate the microfluidic chip and all associated optical components into a compact, low-cost package. Highly compact systems of this kind would eliminate the need for expensive dedicated bench-top instrumentation. As such they would find multiple uses in the home, ambulance and GP’s surgery, where their ability to provide immediate and/or frequent testing would enable faster, more responsive and ultimately more successful treatment. Work undertaken in this thesis focuses on developing highly sensitive analyte detection systems that would enable the use of cheap optical and electronic components. To accomplish this, two separate methods, based on optical filters and time-gated detection of phosphorescent polymer beads, were investigated. We describe a simple technique for fabricating non-emissive colour filters based on the sensitisation of a highly porous nanostructured metal-oxide film with a monolayer of dye molecules. The resultant filters exhibit much less autofluorescence than conventional colour filters, and are a viable low cost alternative to interference filters. In separate work Ru(dpp)3-doped polystyrene/bisphenol A diglycidyl ether polymer phosphorescent beads developed by Dr. Edwards (Imperial College London) were used to demonstrate the feasibility of highly sensitive of low-cost time-gated detection. This method was applied to a simple biotin assay to show their bio-assay applicability.