PC Lipid Microparticles contain attached phosphatidylcholine with the phospholipid headgroup exposed and available for biological interactions. Phosphatidylcholine (PC) is primarily an extracellular phospholipid component of cell membranes and is a key structural lipid. Technicial Notes 1. Total lipid concentration is approximately 1 µmol per 1 mg particles. 2. Trace amounts of a fluorescent lipid are embedded in the particles. The fluor has maximal excitation/emission at approximately 460/540 nm. 3. Particle size is 3 µm.