DiagPoly™ PEG Fluorescent Polystyrene Particles, Red, 0.5 μm (# WHM-S236) are encapsulated with red fluorophores (excitation: 552 nm, emission: 580 nm) with PEG2000 on the surface. The density of liquid suspension is 1.05-1.06 g/mL. Sonicate/Vortex the microspheres before each use. https://www.cd-bioparticles.co....m/product/diagpoly-p