Aspirating and dispensing small volumes of liquids

Abstract

A metering device for aspirating and dispensing a liquid includes a housing; a pumping medium, preferably a gas containing chamber contained within the housing; a channel having a proximate end in fluid communication with the chamber and a distal end in fluid communication with an external environment; a heat or cold source providing a source of heat or cold to the gas containing chamber; and a temperature sensor for measuring the temperature inside the chamber. In a preferred embodiment, the device further includes a pressure sensor for measuring gas pressure inside the chamber, or multiple chambers. A method for aspirating and dispensing a liquid includes: providing a metering device for aspirating and dispensing a liquid that includes a housing; a gas containing chamber contained within the housing, the chamber; a channel having a proximate end in fluid communication with the chamber and a distal end in fluid communication with an external environment; a heat or cold source providing a source of heat or cold to the gas containing chamber; and a temperature sensor for measuring the temperature inside the chamber; providing a source of liquid to be aspirated; bringing the distal end of the channel into contact with the liquid; cooling the gas containing chamber with the heat or cold source to aspirate a first volume of liquid into the device; and heating the gas containing chamber to dispense a second volume of liquid out of the device. In a preferred embodiment, the metering device is a used in a diagnostic analyzer for determining the presence of one or more analytes in a sample.

Description

[0001] This application claims priority to US Patent Application No. 60 / 971,014, filed September 10, 2007, which is hereby incorporated by reference in its entirety. technical field [0002] The present invention relates to the aspiration and dispensing of small volumes of liquids, particularly in the field of diagnostic assays. In particular, the present invention relates to a metering device for pumping and dispensing liquids using small volumes of heated or cooled gas. Background technique [0003] Metering devices are well known in the art, such as those used in medical diagnostic applications. Metering devices, such as pipettes, are generally classified as soft or hard systems. In soft systems, the liquid being pumped or metered is separated from a pumping source such as a piston pump by a large volume of air. Soft systems generally work well when metering larger volumes of liquid (eg, 2 μL or more). However, soft systems are not up to the task of pumping small volum...

AI Technical Summary

Problems solved by technology

Thus, the known systems are not capable of dispensing small volumes of liquids, especially small volumes of liquids, for example in the low-microliter or sub-microliter range, precisely and accurately

[0004] Another problem with conventional metering devices is that the pump system is usually heavy and bulky

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