Suspension polymerization of acrolein type compounds in the presence of appropriate surfactants results in the formation of microspheres in size ranging from 0.03.mu. to 80.mu.. Fluorescent and magnetic microspheres are obtained by carrying out the same polymerization in the presence of appropriate fluorochromic or ferrofluidic compounds, respectively. Hybrido polyacrolein microspheres are obtained by grafting one type of such microspheres on another type. Immunomicrospheres were formed by binding covalently at physiological pH appropriate proteins to the microspheres. The immunomicrospheres can be used for various biological applications, such as specific markers for labelling cell surface receptors, for cell separation, for diagnostic purposes, etc.