Single-cell analysis plays a crucial role in disease identification and treatment evaluation by providing valuable insights into cell-to-cell variability and subpopulations of functional importance. However, traditional techniques like flow cytometry and immunofluorescence staining face limitations in terms of cost, sample preparation, and optical setup. In contrast, microfluidic platforms offer advantages such as reduced sample volumes, enhanced throughput, and decreased contamination risk. This research seminar focuses on the development of a compact multicolor fluorescence detection system that utilises a single laser source and a single photo detector for optofluidic-based single-cell analysis. Furthermore, the application of this technology for detecting circulating tumor cells (CTCs) will be explored. Optofluidic modelling for dynamic size analysis of water-in-oil droplets, providing valuable insights into the propagation of light in optofluidic devices. These insights contribute to the understanding of the optical behaviour within the system. Through this research, we aim to overcome the limitations of traditional techniques and develop a compact and efficient system for single-cell analysis. The ultimate objective is to advance the field of single-cell analysis, particularly in the context of optofluidics and CTC detection, leading to improved diagnostics and targeted therapies in cancer research.