Method for thermally cycling samples of biological material with substantial temperature uniformity

Abstract

An apparatus for thermally cycling samples of a biological material including a thermal block assembly including a plurality of sample holders for receiving samples of biological material; a heat sink thermally coupled to the thermal block assembly, the heat sink transferring heat away from the thermal block assembly to ambient air in contact with the heat sink; a first heat source thermally coupled to the thermal block assembly to provide heat to the thermal block assembly; and a second heat source thermally coupled to the first heat source and configured to provide heat to a portion of the first heat source. The arrangement of the heat sink, first heat source and second heat source can provide substantial temperature uniformity among the plurality of sample holders. The invention also includes a method for thermally cycling samples of biological material.

Description

RELATED APPLICATIONS [0001] This application is a divisional of application Ser. No. 10 / 691,874, filed Oct. 23, 2003, which is a divisional of application Ser. No. 09 / 364,051, filed on Jul. 30, 1999, now U.S. Pat. No. 6,657,169, the entirety of which are hereby incorporated herein by reference.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] This invention relates to an apparatus for heating samples of biological material, and more particularly an apparatus for thermal cycling of DNA samples to accomplish a polymerase chain reaction, a quantitative polymerase chain reaction, a reverse transcription-polymerase chain reaction, or other nucleic acid amplification types of experiments. [0004] 2. Description of the Related Art [0005] Currently, techniques for thermal cycling of DNA samples are well-known. By performing a polymerase chain reaction (PCR), DNA can be amplified. It is desirable to cycle a specially constituted liquid biological reaction mixture through a s...

AI Technical Summary

Benefits of technology

[0010] To attain the advantages and in accordance with the purposes of the invention, as embodied and broadly described herein, the invention includes an apparatus for heating samples of biological material. The apparatus in its preferred embodiment includes: a thermal block assembly including a plurality of sample holders for receiving samples of biological material; a heat sink thermally coupled to the thermal block assembly, the heat sink transferring heat away from the thermal block assembly to ambient air in contact with the heat sink; a first heat source thermally coupled to the thermal block assembly to provide heat to the thermal block assembly; and a second heat source thermally coupled to the first heat source and configured to provide heat to at least a portion of the first heat source. The arrangement of the heat sink, first heat source and second heat source can provide substantial temperature uniformity among the plurality of sample holders.

Problems solved by technology

Even small variations in the temperature between one sample well and another sample well can cause a failure or undesirable outcome of the experiment.

For instance, in quantitative PCR, one objective is to perform PCR amplification as precisely as possible by increasing the amount of DNA that generally doubles on every cycle; otherwise there can be an undesirable degree of disparity between the amount of resultant mixtures in the sample wells.

In addition, temperature errors can cause the reactions to improperly occur.

For example, if the samples are not controlled to have the proper annealing temperatures, certain forms of DNA may not extend properly.

This can result in the primers in the mixture annealing to the wrong DNA or not annealing at all.

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