Method and apparatus for detecting and quantifying bacterial spores on a surface
A method and an apparatus for detecting and quantifying bacterial spores on a surface. In accordance with the method: bacterial spores are transferred from a place of origin to a test surface, the test surface comprises lanthanide ions. Aromatic molecules are released from the bacterial spores; a complex of the lanthanide ions and aromatic molecules is formed on the test surface, the complex is excited to generate a characteristic luminescence on the test surface; the luminescence on the test surface is detected and quantified.
1. A method for detecting and quantifying individual bacterial spores on a test surface, comprising
imaging an aromatic molecule concentration region adjacent to at least one of the individual bacterial spores on the test surface,
wherein the aromatic molecule concentration region is formed by a complex made of an aromatic molecule released by the individual bacterial spore and a lanthanide ion present on the test surface; and
wherein imaging is performed with a micrometric spatial resolution.
2. The method of claim 1 , further comprising, prior to imaging the aromatic molecule concentration region:
capturing the at least one of the individual bacterial spores, and
transferring the at least one of the individual bacterial spores to the test surface.
3. The method of claim 2 , wherein the transferring is performed by way of an adhesive polymer or a swab.
4. The method of claim 3 , wherein the adhesive polymer is selected from the group consisting of PDMS, agar and agarose.
5. The method of claim 3 , wherein the transferring is performed by way of a swab, the method further comprising transferring the at least one of the individual bacterial spores from the swab into water.
6. The method of claim 5 , wherein the water is passed through a water filter.
7. The method of claim 2 , wherein the capturing of the at least one of the individual bacterial spores is from a place of origin selected from the group consisting of water and air.
8. The method of claim 2 , wherein the transferring of the at least one of the individual bacterial spores is from a place of origin to a filter selected from the group consisting of an air filter and a water filter.
9. The method of claim 1 , wherein the aromatic molecule is released by germination of its respective individual bacterial spore.
10. The method of claim 9 , wherein germination is induced by contacting the at least one individual bacterial spore with L-alanine, L-asparagine, or D-glucose.
11. The method of claim 1 , wherein the aromatic molecule is selected from the group consisting of dipicolinic acid, dipicolinate, and mixtures thereof.
12. The method of claim 1 , wherein the aromatic molecule interacts with the test surface resulting in a derivative of the aromatic molecule.
13. The method of claim 1 , wherein the aromatic molecule is released by lysis of the at least one individual bacterial spore.
14. The method of claim 13 , wherein the lysis is induced by way of a method of lysis selected from the group consisting of microwaving, autoclaving, sonication, plasma cleaning, dry heating and hydrogen chloride gassing.
15. The method of claim 1 , wherein the imaging comprises imaging the aromatic molecule concentration region of each of a plurality of the individual bacterial spores clustered together on the test surface.
16. The method of claim 1 , wherein the individual bacterial spores are embedded in the test surface.
17. The method of claim 1 , wherein the test surface is an adhesive polymer selected from the group consisting of PDMS, agar, agarose PDMS together with agar, and PDMS together with agarose.
18. The method of claim 1 , wherein the lanthanide ion is selected from the group consisting of terbium ions, europium ions, or a mixture thereof.
19. The method of claim 3 , wherein the adhesive polymer is a totally or partially optically transparent adhesive polymer.
20. An apparatus for detecting and quantifying individual bacterial spores, the apparatus comprising:
a test surface comprising one or more adhesive polymers and one or more lanthanide ions, the test surface including at least one bacterial spore, each said at least one bacterial spore adapted to release aromatic molecules such that the at least one bacterial spore and respective aromatic molecules are in close proximity to each other so as to render the at least one bacterial spore individually detectable, quantifiable, and/or imageable with a micrometric spatial resolution;
an ultraviolet light radiation device adjacent to the test surface to excite a complex made of a lanthanide ion of the one or more lanthanide ions and an aromatic molecule of the aromatic molecules and generate a characteristic luminescence of the complex; and
an imaging device for imaging the at least one bacterial spore corresponding to the luminescence, the imaging device configured to image with a micrometric spatial resolution.
21. The apparatus of claim 20 , wherein the one or more adhesive polymers is a totally or partially optically transparent adhesive polymer.
22. The apparatus of claim 20 , wherein a microscope is connected to the imaging device.
23. The apparatus of claim 20 , wherein the test surface exhibits two conditions such that:
in a first condition, the test surface comprises the one or more adhesive polymers, the one or more lanthanide ions and the at least one bacterial spore; and
in a second condition, the test surface comprises the one or more adhesive polymers, an excited complex of one of the lanthanide ions and the aromatic molecule released from the respective at least one bacterial spore, and the respective at least one bacterial spore.