1. Field of the Invention
The present invention relates to an object-capturing device, which captures objects, such as microorganisms and chemical substances, in the air, and a method for using the object-capturing device.
2. Description of the Related Art
Conventionally, a technique of capturing objects, such as air-borne microorganisms and chemical substances, by sucking air through a filter and separating the objects by the filter has been well-known. A well-known capturing device for capturing air-borne microorganisms has a carrier, which undergoes a phase transition from gel to sol at a temperature raised from room temperature, on a capturing dish, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2009-131186. Such capturing device is attached to an impactor-type air sampler. When air sucked by the air sampler collides with the carrier, microorganisms carried by the air flow are captured by the carrier in a gel phase. The carrier solates by raising the temperature, and thereby the captured microorganisms with the carrier in a sol phase are obtained from the capturing dish. The obtained microorganisms are counted according to a predetermined counting method.
A well-known method for counting microorganisms is the ATP method, which quantifies adenosine triphosphates (ATPs) extracted from microorganisms and thereby counts the microorganisms, as disclosed in, for example, Japanese Patent Application Laid-Open No. 11-137293. The ATP method extracts ATPs contained in the microorganisms by contacting the captured microorganisms with an ATP extracting reagent, and counts the microorganisms based on the intensity of luminescence measured when the extracted ATPs reacts with a luminescence reagent.
For example, a method for counting captured microorganisms based on the number of microorganism colonies cultured in a plate medium requires several days. On the other hand, the ATP method requires about one to several hours from the capturing of microorganisms to the counting of the microorganisms. Thus, the ATP method dramatically reduces the required time.
However, the ATP method counts microorganisms based on weak luminescence intensity. Substances that act as disturbance factors may be contained in a sample to be counted. Consequently, these substances need to be minimized.
A conventional capturing device, such as a device disclosed in Japanese Patent Application Laid-Open No. 2009-131186, has a carrier exposed on a capturing dish. Thus, for example, microorganisms other than those to be tested, or other substances that act as disturbance factors may attach onto the exposed carrier during the time after microorganisms are captured onto the carrier in an air sampler and before the microorganisms are counted. Particularly, when a test site where microorganisms are captured is far from a site where the microorganisms are counted, the carrier may be more heavily contaminated.
In other words, when the capturing device, such as the device disclosed in Japanese Patent Application Laid-Open No. 2009-131186, is used, the carrier is contaminated during the time after the carrier is removed from the air sampler and before the microorganisms are counted, and thereby the microorganisms captured at the test site may not be accurately counted.