Colorable polymeric particles with biological probes

A method of preparing polymeric particles with photographic couplers, such polymeric particles being useful in a microarray, the method comprising the steps of: (a) preparing an organic composition by combining a photographic coupler and a high boiling organic solvent; (b) preparing a separate aqueous composition comprising polymeric particles with functionally active groups on their surfaces; (c) combining the organic composition of step (a) with the aqueous composition of step (b), thereby effecting a loading of said photographic coupler and high boiling organic solvent into said polymeric particles; and (d) attaching biological probes to the functionally active groups on the surfaces of the loaded polymeric particles of step c). Polymeric particles made by the method is also disclosed.