Platelets were once viewed merely as blood clotting cells. Their functions have been shown to be far more diverse, including immune and cancer modulation. How platelets are produced from their precursor cell, megakaryocytes, is a highly debated topic. There are two main theories of where platelets are produced: bone marrow sinusoids and the lung vasculature. These concepts has been mimicked in vitro to produce platelets for therapeutic purposes. Efficient in vitro platelet production has however been challenging. To produce platelets, the Poole group (UK) used an in vitro, microfluidics device with a branched structure, modelled from the architecture of the lung vasculature. Here, two alternative microfluidics systems were designed. The ‘smooth branched’ design maintained the branching structure of its predecessor but had rounded edges instead of sharp. The sinusoidal’ design consisted of straight channels where the width increased and decreased in a pulsatile manner. The efficiency and platelet producing mechanisms of these three systems were characterised using brightfield, laser scanning confocal and scanning electron microscopy as well as flow cytometry. The branched system was the most efficient at producing platelets. Removal of sharp corners from this system seemed to have little to no effect on production efficiency or damage to cells. All three systems exhibited proplatelet formation. Blockages and debris were commonly observed, indicating flawed chip design and high stress levels. The data from this work should be used to influence future microfluidic device designs. Branching points appear useful for inducing catch and release, however branching points should be redesigned to reduce blockages.
Investigating In Vitro Platelet Production Through a Microscopy Lens
Furniss, J. A. (Author). 23 Jan 2024
Student thesis: Master's Thesis › Master of Science by Research (MScR)