The aim of this thesis is to investigate and develop a microfluidic platform for the detection and size characterization of individual magnetic micromarkers suspended in liquid along with the capture and quantification of microorganisms such as E.coli bacteria by labeling them with magnetic particles (MPs). Two methods were studied for the above-mentioned development: (1) a dark field video imaging system and (2) magnetophoresis, as quick, inexpensive and compact approaches for microbiomolecule identification and quantification in ex vivo biomedical applications. In the first technique, dynamic processes and interactions of micro/nano particles in liquids (Brownian motion) are being utilized whereas in the second method it is the induced translational motion of MPs due to the externally applied magnetic field gradient. The proposed microfluidic platform is suitable for small sample volumes (10 L), where microsize precision is required. This research has been mostly restricted to experimental examination of E.coli comprised solvent, yet the system is applicable for obtaining clinical information about diverse liquid contents when an additional biological binding protocol is provided. A minor limitation associated with the experimental methods is that the concentration range of micromarkers/magnetic particles in the sample needs to be adjusted in such a manner that the number of individual particles in the microscopes field of view is sufficient.