Abstract: An ultrathin-walled multiwell reactor for heat block thermocycling of samples includes an array of small-volume wells of identical height with similarly shaped sample wells formed in a top surface of a heat block. The multiwell plates are preferentially vacuum formed out of a 30-50 micron thick thermoplastic film and can be used for rapid, oil-free temperature cycling of small (1-10 &mgr;l) volume samples.

Abstract: A heat block thermocycler to perform rapid PCR in multiple small-volume samples (1-20 &mgr;l) employing, low profile, low thermal mass sample block the temperature of which can be rapidly and accurately modulated by a single thermoelectric pump (thermoelectric module). An array of spaced-apart sample wells is formed in the top surface of the block. The samples are placed into the wells of ultrathin-walled (20-40 &mgr;m) multiwell plate and located into the sample block. The heated lid tightly seals the individual wells by pressing the sealing film to the top surface of the multiwell plate. Air pressure arising inside the tightly sealed wells at elevated temperatures deforms the elastic walls of the wells of the ultrathin-walled plate and brings them into close thermal contact with the sample block. A gasket thermally isolates the sample block from the heated lid. The PCR reactions (30 cycles) can be performed in 10-30 minutes.