METHOD OF EXCITING A MECHANICAL RESONANCE IN A STRUCTURAL COMPONENT OF A MICROORGANSIM

Abstract

Method of exciting an electro-magnetic mechanical resonance in a structural component (2, 3) of a microorganism (1), the method comprising exposing said microorganism to an oscillating magnetic field (H), which oscillates at least at a first frequency, characterized in that said first frequency corresponds to a frequency of a mechanical resonance of said structural component. The invention is further directed to a method of selecting effective operating parameters to perform the invention. Under further aspects, the invention relates to applications of the method in in the technical fields of water treatment, nutrition industry, cell culture industry or paper industry as well as in the general reduction or limitation of the reproduction of specific germs in all areas, as well as in human and animal tissue cultures, ex vivo (extracorporal) of blood preparations. In a specific embodiment of the invention, the microorganism is brought in contact with magnetic nanoparticles, which are designed to attach themselves to the structural component of the microorganism.

Claims

1. Method of exciting a mechanical resonance in a structural component (2, 3) of a microorganism (1), the method comprising exposing said microorganism to an oscillating magnetic field (H), which oscillates at least at a first frequency, characterized in that said first frequency corresponds to a frequency of a mechanical resonance of said structural component.

2. Method according to claim 1, wherein said first frequency is in the range up to Megahertz, in particular in the range 0.01 Hertz to 400 kHz.

3. Method according to claim 1, wherein said oscillating magnetic field (H) is generated by driving an alternating current of said first frequency through a coil arrangement (11) comprising at least one coil (11, 11).

4. Method according to claim 3, wherein said coil arrangement (11) comprises a pair of coils, wherein the coils of the pair of coils are arranged on a common axis (A) and spaced apart in direction of said axis, and wherein said microorganism (1) is placed in a space between said coils (11, 11) of the pair of coils.

5. Method according to claim 4, wherein the direction of said alternating current is either parallel in said coils (11, 11) of the pair of coils or is opposite in said coils of the pair of coils.

6. Method according to claim 4, wherein alternating current of said first frequency is driven through a first coil (11) of said pair of coils and wherein alternating current of a second frequency is driven through a second coil (11) of said pair of coils.

7. Method according to claim 1, wherein a combination of duration of said exposing and of field strength of said oscillating magnetic field is selected such that a microbial activity is reduced, in particular such that said structural component of said microorganism is damaged.

8. Method according to claim 1, wherein said microorganism (1) is brought in contact with magnetic nanoparticles at least while exposing said microorganism to said oscillating magnetic field (H).

9. Method according to claim 8, wherein said magnetic nanoparticles are designed to attach themselves to said structural component of said microorganism.

10. Method of rating a first frequency regarding efficacity, wherein the method comprises the steps observing a pre-treatment activity of a first microorganism, exposing said first microorganism to an oscillating magnetic field oscillating at said first frequency, observing a post-treatment activity of said first microorganism, determining a rating of efficacity for said first frequency in dependence of the difference between said post-treatment activity and said pre-treatment activity.

11. The method according to claim 10, wherein the rating of efficacity applies to a set of values of operating parameters of the method according to claim 1, the set comprising at least said first frequency.

12. Method according to claim 11, wherein said set of values of operating parameters is defined as said first frequency, and/or said first frequency and the relative direction of the alternating current in a pair of coils, and/or said first frequency and said second frequency.

13. Method of determining a species-specific frequency of the method according to claim 1, wherein the method comprises repeatedly performing the method according to one of claims 1 to 9 with various values of said first frequency, wherein in each repetition of the method according to claim 10 is applied to a microorganism of a first species, wherein a table of ratings of efficacity in dependency of said first frequency is established, wherein the frequency with the highest rating of efficacity is selected as the species-specific frequency for said first species.

14. Method according to claim 13, wherein a frequency range for said first frequency is estimated based on observed movements of said first species of microorganisms and wherein said various values of said first frequency are selected from said frequency range.

15. Use of the method according to claim 1 for reduction of microbial activity in the technical fields of water treatment, nutrition industry, cell culture industry or paper industry as well as in the general reduction or limitation of the reproduction of specific germs in all areas, as well as in human and animal tissue cultures, ex vivo, i.e. extracorporal, treatment of blood preparations.

16. Coil arrangement (11) for performing the method according to claim 3, wherein the coil arrangement is formed of a number of mutually isolated loops of flexible wire, in particular of stranded wire, wherein said loops surround a free space into which said microorganism can be placed, wherein said loops are connected in series through a multiple connector pair, allowing for connecting and disconnecting several of said loops simultaneously.

Description

[0061] The invention shall now be further exemplified with the help of figures. The figures show:

[0062] FIG. 1 a schematic view of a situation occurring during the method according to the invention;

[0063] FIG. 2.a) and 2.b) cross-sections through coil-arrangements used for performing embodiments of the method;

[0064] FIG. 3 a schematic view of an apparatus for performing the method according to the invention;

[0065] FIG. 4.a) and 4.b) schematic views of variants to drive an alternating current through the coil arrangement;

[0066] FIG. 5 a photography of embodiments of flexible coil arrangements;

[0067] FIG. 6 a photography of an embodiment of a coil arrangement with male and female connector parts in the disconnected state;

[0068] FIG. 7 a photography of a detail of partially assembled coil arrangement.

[0069] FIG. 1 shows schematically and by means of an illustrative simplified example, a situation occurring during the method according to the invention. A microorganism 1 is exposed to an oscillating magnetic field H. The orientation and oscillating polarity of the magnetic field is symbolically indicated by arrows. The microorganism shown has a cell membrane 2 and organelles 3. In the case shown, the cell membrane is the structural component, which undergoes a periodical mechanical deformation. Extreme positions of the deformation are shown in double lines and in double dashed lines, respectively. The orientation of the magnetic field after half a period of one oscillation of the magnetic field is shown as arrows with dashed lines. The frequency of the applied oscillating magnetic field corresponds to the resonance frequency related to the periodical mechanical deformation.

[0070] FIG. 2.a) shows a cross section through coil-arrangement comprising a pair of coils arranged as Helmholtz-pair. Both coils of the pair of coils are arranged on a common axis A, which is indicated as dash-dotted line. First coil 11 and second coil 11 of the pair of coils. An oscillating current is driven through both the coils such that the current runs in parallel in both coils. This way, the magnetic field H of the first coil is oriented in the same direction as the field of the second coil. The magnetic fields produced by the coils add up to a homogeneous magnetic field in a region between the coils and close to the axis. A container 20, which carries microorganisms, is placed in the space between the coils.

[0071] FIG. 2.b) shows a cross section through coil-arrangement similar to the one shown in FIG. 2.a), but with the difference, that the current is driven through the coils of the pair of coils in opposite direction. This way, the magnetic field generated by the first coil is directed in opposite direction compared to the field direction of the second coil. The axial component of the magnetic field, i.e. the field component parallel to the axis A, has a gradient form in the space between the two coils of the pair of coils. The microorganism placed in the space between the coils are exposed to an oscillating magnetic field gradient.

[0072] Coil-arrangements as shown in FIG. 2.a) and FIG. 2.b) may be driven by a single current source, when the two coils are connected in series. Alternatively, each coil may be driven by a separate current source. In the latter case, the frequency of the oscillation may be selected differently for the current in the first and the second coil. In this case, the magnetic field created oscillates between the situations shown in FIG. 2.a) and FIG. 2.b) as extremal situation.

[0073] FIG. 3 shows a schematic view of an apparatus 10 for performing the method according to the invention. The apparatus comprises a coil-arrangement 11, which comprises a first coil 11 and a second coil 11. The geometry of the coil-arrangement may e.g. be a Helmholtz-pair, as shown in FIG. 2.a) or FIG. 2.b). A two-channel RF-frequency generator 12 has two output channels, which deliver each an oscillating signal oscillating at a selectable first frequency and second frequency, respectively. A two-channel broad band power amplifier amplifies the signals of the RF-frequency generator such that the first coil 11 and the second coil 11 can be driven with an oscillating current of the first and the second frequency. A trimmer 14, i.e. an adjustable capacity, for phase compensation is connected in series to each of the coil. The adjustable capacity may be built as a capacitance decade dimensioned for high voltages across the coils, e.g. for voltages in the range 50 V to 5 KV.

[0074] FIG. 4.a) shows a variant of driving an alternating current I(t) through the coil arrangement 11, symbolically indicated as coil having inductance L. The coil arrangement may have more complicated structure than indicated by the symbol in this schematic diagram. A variable capacitor C is connected in series to the coil arrangement. The complete configuration has a total resistance R.sub.tot, which includes the DC resistance of the coil, a resistance due to the frequency dependent skin effect, the dielectric loss of the capacitor and the output impedance of the source. Applying an oscillating voltage U.sub.s(t), provided by an AC-voltage source, leads to a current I(t) flowing through the coil arrangement and producing the oscillating magnetic field used for the method according to the invention. The voltage source may be able to provide a DC voltage, too, in particular to provide a DC-offset in addition to the AC-voltage. The capacitor may be set to a capacitance value, which fits to the inductance of the coil arrangement. An alternative to the variable capacitor is a capacitor decade, as shown in FIG. 4.b).

[0075] FIG. 5 shows a photography of two embodiments of flexible coil arrangements. They are positioned around models of parts of a human skeleton, in order to illustrate the possibility of locally applying oscillating magnetic fields by means of these coil arrangements. The coil arrangements shown comprise multiple wires in a common tube and connected at both ends of the tube by a multiple connector pair, in the case shown by DSUB-15 connectors. Inlet and outlet wire are provided with connectors that enable connecting the coil arrangement to a power source. The tube is wound to several circular loops. In the example coil arrangement shown on the left half of the photo, the tube forms 16 loops. The tube, which in this example is formed as a braided sleeve, contains 16 wires, such that a total of 256 windings results in the complete coil arrangement.

[0076] FIG. 6 shows a photography of an embodiment of a coil arrangement with male and female connector parts in the disconnected state. In this state, it is simple to position the coil arrangement at a new place, where magnetic fields are to be applied. Before starting operation, the male and female connector parts are connected, and the inlet and outlet wire are connected to a power supply.

[0077] FIG. 7 shows a photography of a detail of partially assembled coil arrangement. Stranded wires are connected to the connector part shown in the lower part of the photo. In the upper part, only three positions of the DSUB-15 connector are connected in the state of assembling as shown here.

LIST OF REFERENCE SIGNS

[0078] 1 microorganism [0079] 2 cell membrane [0080] 3 organelle [0081] 10 apparatus for performing the method [0082] 11 coil arrangement [0083] 11 first coil (of pair of coils) [0084] 11 second coil (of pair of coils) [0085] 12 two channel RF-frequency generator [0086] 13 two channel broad band power amplifier [0087] 14 trimmer for phase compensation [0088] 15 inlet wire [0089] 16 outlet wire [0090] 17 multiple connector [0091] 18 tube [0092] 19 stranded wire [0093] 20 sample/container for microorganism [0094] A axis [0095] H magnetic field