  We optimize and characterize the preparation of 3-trimethoxysilyl
propylmethacrylate (TPM) colloidal suspensions for three-dimensional confocal
microscopy. We revisit a simple synthesis of TPM microspheres by nucleation of
droplets from pre-hydrolyzed TPM oil in a 'zero-flow' regime, and demonstrate
how precise and reproducible control of particle size may be achieved via
single-step nucleation with a focus on how the reagents are mixed. We also
revamp the conventional dyeing method for TPM particles to achieve uniform
transfer of a fluorophore to the organosilica droplets, improving particle
identification. Finally, we illustrate how a ternary mixture of tetralin,
trichloroethylene and tetrachloroethylene may be used as a suspension medium
which matches the refractive index of these particles while allowing
independent control of the density mismatch between particle and solvent.
