This thesis presents an experimental study of the effect that particle size and shape have on nanoparticle magination and adhesion propensity in micro-capillaries. With the use of half elliptical cross-section microfluidic channels that were fabricated using photolithography as well as wet and dry etching techniques and geometrically mimetic of human microcirculation, particles ranging from 93 to 970 nm were flown and imaged individually adhering to the channel walls. The results show a significant increase in particle adhesion below 200 nm as well as the emergence of a critical particle diameter above which no particle adherence was observed. The volume delivery efficiency was also shown to increase below 200 nm, providing insight for the rational design of nanocarriers for targeted cancer therapeutics. / text