The present invention provides the use of a composition comprising a block polymer as a support matrix in the manipulation, processing or analysis of particles, such as cells and fluorescent beads. In a preferred embodiment, the composition exhibits gel-sol thermoreversibility, micelle formation under gelling conditions, optically compatible, controllable surfactant properties, molecular sieving properties and biocompatibility. Further aspects of the invention provide (a) a support matrix composition comprising a block polymer, fluorescent beads and/or a dye for use in the manipulation, processing or analysis of particles, (b) a multichamber plate coated in a support matrix composition and (c) kits for producing the same.