The assignee for this patent application is 3m
Reporters obtained the following quote from the background information supplied by the inventors: "Food-borne illnesses and hospital-acquired infections resulting from microorganism contamination are a concern in numerous locations all over the world. Thus, it is often desirable or necessary to assay for the presence of bacteria or other microorganisms in various clinical, food, environmental, or other samples, in order to determine the identity and/or the quantity of the microorganisms present.
"Bacterial DNA or bacterial RNA, for example, can be assayed to assess the presence or absence of a particular bacterial species even in the presence of other bacterial species. The ability to detect the presence of a particular bacterium, however, depends, at least in part, on the concentration of the bacterium in the sample being analyzed. Bacterial samples can be plated or cultured to increase the numbers of the bacteria in the sample to ensure an adequate level for detection, but the culturing step often requires substantial time and therefore can significantly delay the assessment results.
"Concentration of the bacteria in the sample can shorten the culturing time or even eliminate the need for a culturing step. Thus, methods have been developed to isolate (and thereby concentrate) particular bacterial strains by using antibodies specific to the strain (for example, in the form of antibody-coated magnetic or non-magnetic particles). Such methods, however, have tended to be expensive and still somewhat slower than desired for at least some diagnostic applications.
"Concentration methods that are not strain-specific have also been used (for example, to obtain a more general assessment of the microorganisms present in a sample). After concentration of a mixed population of microorganisms, the presence of particular strains can be determined, if desired, by using strain-specific probes.
"Non-specific concentration or capture of microorganisms has been achieved through methods based upon carbohydrate and lectin protein interactions. Chitosan-coated supports have been used as non-specific capture devices, and substances (for example, carbohydrates, vitamins, iron-chelating compounds, and siderophores) that serve as nutrients for microorganisms have also been described as being useful as ligands to provide non-specific capture of microorganisms.
"Various inorganic materials (for example, hydroxyapatite and metal hydroxides) have been used to non-specifically bind and concentrate bacteria. Physical concentration methods (for example, filtration, chromatography, centrifugation, and gravitational settling) have also been utilized for non-specific capture, with and/or without the use of inorganic binding agents. Such non-specific concentration methods have varied in speed, cost (at least some requiring expensive equipment, materials, and/or trained technicians), sample requirements (for example, sample nature and/or volume limitations), space requirements, ease of use (at least some requiring complicated multi-step processes), suitability for on-site use, and/or effectiveness."
In addition to obtaining background information on this patent application, VerticalNews editors also obtained the inventors' summary information for this patent application: "Thus, we recognize that there is an urgent need for processes for rapidly detecting pathogenic microorganisms. Such processes will preferably be not only rapid but also low in cost, simple (involving no complex equipment or procedures), and/or effective under a variety of conditions (for example, with varying types of sample matrices, varying bacterial loads, and varying sample volumes).
"Briefly, in one aspect, this invention provides a process for non-specifically concentrating the strains of microorganisms (for example, strains of bacteria, fungi, yeasts, protozoans, viruses (including both non-enveloped and enveloped viruses), and bacterial endospores) present in a sample, such that the microorganisms remain viable for the purpose of detection or assay of one or more of the strains. The process comprises (a) providing a concentration agent (preferably, a particulate concentration agent) that comprises diatomaceous earth bearing, on at least a portion of its surface, a surface treatment comprising a surface modifier comprising titanium dioxide, fine-nanoscale gold or platinum, or a combination thereof; (b) providing a sample (preferably, in the form of a fluid) comprising at least one microorganism strain; and © contacting (preferably, by mixing) the concentration agent with the sample such that at least a portion of the at least one microorganism strain is bound to or captured by the concentration agent. Preferably, the process further comprises detecting the presence of the at least one bound microorganism strain (for example, by culture-based, microscopy/imaging, genetic, bioluminescence-based, or immunologic detection methods) and/or segregating (preferably, by gravitational settling) the resulting microorganism-bound concentration agent. The process can optionally further comprise separating the resulting segregated concentration agent from the sample.
"The process of the invention does not target a specific microorganism strain. Rather, it has been discovered that certain relatively inexpensive, inorganic materials can be surprisingly effective in capturing a variety of microorganisms. Such materials can be used to concentrate the microorganism strains present in a sample (for example, a food sample) in a non-strain-specific manner, so that one or more of the microorganism strains (preferably, one or more strains of bacteria) can be more easily and rapidly assayed.
"The process of the invention is relatively simple and low in cost (requiring no complex equipment or expensive strain-specific materials) and can be relatively fast (preferred embodiments capturing at least about 70 percent (more preferably, at least about 80 percent; most preferably, at least about 90 percent) of the microorganisms present in a sample in less than about 30 minutes, relative to a corresponding control sample without concentration agent). In addition, the process can be effective with a variety of microoganisms (including pathogens such as both gram positive and gram negative bacteria) and with a variety of samples (different sample matrices and, unlike at least some prior art methods, even samples having low microorganism content and/or large volumes). Thus, at least some embodiments of the process of the invention can meet the above-cited urgent need for low-cost, simple processes for rapidly detecting pathogenic microorganisms under a variety of conditions.
"In another aspect, the invention also provides a diagnostic kit for use in carrying out the process of the invention, the kit comprising (a) a concentration agent (preferably, a particulate concentration agent) that comprises diatomaceous earth bearing, on at least a portion of its surface, a surface treatment comprising a surface modifier comprising titanium dioxide, fine-nanoscale gold or platinum, or a combination thereof; and (b) a testing container (preferably, a sterile testing container) for use in carrying out the process of the invention. Preferably, the diagnostic kit further comprises one or more components selected from microorganism culture media, lysis reagents, buffers, genetic detection assay components, bioluminescence detection assay components, instructions for carrying out the process, and combinations thereof.
"In yet another aspect, the invention provides a concentration agent comprising titanium dioxide, fine-nanoscale gold or platinum, or a combination thereof on a particulate support selected from diatomaceous earth, metal oxide-modified diatomaceous earth, and combinations thereof.
"In still another aspect, the invention provides a process for preparing a concentration agent comprising (a) providing a particulate support selected from diatomaceous earth, metal oxide-modified diatomaceous earth, and combinations thereof; and (b) depositing fine-nanoscale gold or platinum on the support by physical vapor deposition.
"In yet another aspect, the invention provides a process for preparing a concentration agent comprising (a) providing a particulate support selected from diatomaceous earth, metal oxide-modified diatomaceous earth, and combinations thereof; (b) providing a hydrolyzable titanium dioxide precursor compound; © combining the support and the compound; and (d) hydrolyzing the compound so as to deposit titanium dioxide on the support.
BRIEF DESCRIPTION OF DRAWING
"These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawing, wherein:
"FIG. 1 shows, in side sectional view, an apparatus that was used in preparing concentration agents for use in carrying out the embodiments of the process of the invention described in the examples section below.
"FIG. 2 shows, in perspective view, the apparatus of FIG. 1.
"These figures, which are idealized, are not drawn to scale and are intended to be merely illustrative and nonlimiting."
For more information, see this patent application: Kshirsagar, Manjiri T.; Kshirsagar, Tushar A.; Wood, Thomas E. Microorganism Concentration Agent and Method of Making. Filed
Keywords for this news article include: Chemicals, Chemistry, Nanoscale, Treatment, Light Metals, Nanotechnology, Silicon Dioxide, Titanium Dioxide, Diatomaceous Earth, Emerging Technologies, 3m
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