Compositions for use in security marking

Abstract

Provided is a security marking composition for marking an area of land, which security marking composition is readily capable of transfer from the land to a person or to a vehicle, which security marking composition comprises: (a) a carrier selected from a polymer and an emulsion; and (b) a security marker.

Claims

1. A security marking composition for marking an area of land, which security marking composition is readily capable of transfer from the land to a person or to a vehicle, which security marking composition comprises: (a) a carrier comprising a polymer; and (b) a security marker; wherein the security marker comprises nucleic acid; wherein the polymer is in the form of threads of polyacrylamide or synthetic spider silk protein, the threads being configured to break and stick to skin or clothing on contact.

2. A security marking composition according to claim 1, wherein the nucleic acid is DNA.

3. A security marking composition according to claim 1, wherein the security marker comprises: a plurality of identical first synthetic nucleotide oligomers; and a plurality of identical second synthetic nucleotide oligomers which are different to the first synthetic nucleotide oligomers, wherein each of the first synthetic nucleotide oligomers comprises a first primer binding sequence of bases, a first identifier sequence of three to seven bases in length, and a second primer binding sequence of bases, the first identifier sequence being disposed between the first and second primer binding sequences, wherein each of the second synthetic nucleotide oligomers comprises a third primer binding sequence of bases, a second identifier sequence of three to seven bases in length, and a fourth primer binding sequence of bases, the second identifier sequence being disposed between the third and fourth primer binding sequences, wherein the first identifier sequence is different to the second identifier sequence, and wherein information on the owner of the composition is identifiable from the first and second identifier sequences using a database.

4. A composition according to claim 3, wherein the first identifier sequence has a length in the range four to six bases.

5. A composition according to claim 3, wherein the second identifier sequence has a length in the range four to six bases.

6. A composition according to claim 3, wherein the first and second primer binding sequences are different to the third and fourth primer binding sequences.

7. A composition according to claim 3, wherein the first and second primer binding sequences are identical to the third and fourth primer binding sequences.

8. A composition according to claim 3, wherein the first and second primer binding sequences are different.

9. A composition according to claim 3, wherein the third and fourth primer binding sequences are different.

10. A composition according to claim 3, wherein the first, second, third and fourth primer binding sequences each have a length in the range 5 to 40 bases.

11. A composition according to claim 3, wherein each of the first synthetic nucleotide oligomers consists of the first primer binding sequence, the first identifier sequence, and the second primer binding sequence.

12. A composition according to claim 3, wherein each of the second synthetic nucleotide oligomers consists of the third primer binding, the second identifier sequence, and the fourth primer binding sequence.

13. A composition according to claim 1, further comprising one or more of an adhesive, a fluorescent material, a plurality of microdots, a solvent, a propellant, a grease and a gel.

14. A composition according to claim 10, wherein the first, second, third and fourth primer binding sequences each have a length in the range of 10 to 30 bases.

15. A composition according to claim 14, wherein the first, second, third, and fourth primer binding sequences each have a length in the range of 15 to 20 bases.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) For a better understanding of the present invention and to show how the same may be carried into effect, embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which:

(2) FIG. 1 shows a schematic illustration of first and second synthetic nucleotide oligomers in accordance with an embodiment of the present invention;

(3) FIG. 2 shows a schematic illustration of a method of determining an owner of a composition in accordance with an embodiment of the present invention; and

(4) FIG. 3 shows a schematic illustration of a method used to lengthen and amplify one of the nucleotide oligomers in accordance with an embodiment of the present invention.

(5) FIG. 4 shows the sticky emulsion being distributed directly on vegetation, in this case in a shrubby area. The method for dispersal is quite straight forward using irrigation equipment such as standard water hoses, sprinklers or even water throwers.

(6) FIG. 5 shows commercially available polyacrylamide balls, which may be employed as a carrier in the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

(7) Compositions of the present invention comprise a mixture of two different synthetic nucleotide oligomers. Examples are illustrated in FIG. 1. The first synthetic nucleotide oligomer 2 comprises a primer binding sequence 4, a primer binding sequence 6, and an identifier sequence 8 disposed between the primer binding sequences. The second synthetic nucleotide oligomer 10 is similar in structure to the first oligomer and comprises a primer binding sequence 12, a primer binding sequence 14, and an identifier sequence 16 disposed between the primer binding sequences.

(8) The identifier sequences are used to identify the composition. The identifier sequences of the two oligomers are different and together provide a unique code for the composition. The identifier sequences have three to seven bases, preferably 4 to 6 bases. The primer binding sequences are identical or complementary to portions of standard primer sequences used for amplifying the oligomer during analysis.

(9) FIG. 2 shows a method of analyzing a composition comprising a mixture of two different synthetic nucleotide oligomers 2, 10 as described above in relation to FIG. 1.

(10) A sample of the composition is taken and the nucleotide oligomers are isolated. The nucleotide oligomers are then lengthened using primers and then amplified using a polymerase chain reaction. One key feature is that the primers are longer than the primer binding sequences of the nucleotide oligomers 2, 10. Accordingly, the nucleotide oligomers are increased in length as illustrated in Step A of FIG. 2. The extended oligomers retain the same length of identifier sequence 8, 16 but have much longer primer sequences 18, 20, 22, 24 when compared to the original primer binding sequences 4, 6, 12, 14. These extended oligomers are amplified in number using a polymerase chain reaction as illustrated in Step B and then sequenced as illustrated in Step C. The longer oligomers can be sequenced using standard sequencing methods. In contrast, it would be difficult to sequence the shorter oligomers accurately using standard methods. Finally, in Step D a database is used to match the identified sequences with information about the owner of the composition.

(11) FIG. 3 shows in more detail a method used to lengthen and amplify one of the nucleotide oligomers. As before, the synthetic nucleotide oligomer 2 comprises a first primer binding sequence 4, a second primer binding sequence 6, and an identifier sequence 8 disposed between the primer binding sequences.

(12) Identification of the DNA security marker is an important part of certain embodiments of the invention, and will now be described in detail.

(13) In Step 1, a PCR primer 30 is bound to the second primer binding sequence 6. The PCR primer 30 has a terminal portion 32 at its 3′ end which is complementary to the second primer binding sequence 6 for binding thereto. The PCR primer 30 also has a primer binding site 34 for Sanger sequencing amplification at a position other than the terminal portion 32. In this case, the primer binding site 34 is at the 5′ end of the PCR primer 30 and comprises a sequence corresponding to a reverse sequence primer.

(14) In Step 2, the PCR primer sequence 30 is extended using the synthetic nucleotide oligomer 2 as a template so as to form an extended sequence 40 comprising portions 36 and 38 which are complementary to the first primer binding sequence 4 and the identifier sequence 8 of the original synthetic nucleotide oligomer 2.

(15) In Step 3, a second PCR primer 42 is bound to the portion 36 of the extended sequence 40. The second PCR primer 42 has a terminal portion 44 at its 3′ end which is complementary to the portion 36 of the extended sequence 40. As the portion 36 is complementary to the first primer binding sequence 6, then the terminal portion 44 of the second primer 42 is identical to the original first primer binding sequence 4.

(16) The second PCR primer 42 also has a primer binding site 46 for Sanger sequencing amplification at a position other than the terminal portion 44. In this case, the primer binding site 46 is at the 5′ end of the PCR primer 42 and comprises a sequence corresponding to a forward sequence primer.

(17) In Step 4, the second PCR primer 42 is extended using the extended sequence 40 as a template so as to form a final extended sequence 48 comprising portion 50 which is complementary to portion 38 and thus identical to the identifier sequence 8 of the original synthetic nucleotide oligomer 2. The final extended sequence 48 thus comprises a sequence of a forward sequence primer 46, a sequence of a reverse sequence primer 52, and a sequence 50 identical to the identifier sequence 8 of the original synthetic nucleotide oligomer 2.

(18) In Step 5, the final extended sequence 48 is amplified in number using PCR amplification. The amplification product can then be sequenced using the forward and reverse sequencing primer sites.

(19) The same method steps can be utilized for amplification and sequencing of a second nucleotide oligomer in the composition using a third and fourth PCR primer. In this case, if the first and second PCR primers harbour the same sequencing primer binding sites as the third and fourth PCR primers respectively, the nucleotide oligomers should be amplified and sequenced separately. Alternatively, if the first and second PCR primers harbour different sequencing primer binding sites to the third and fourth PCR primers respectively, the nucleotide oligomers may be amplified in one reaction. However, sequencing analysis should still be performed separately.

(20) The compositions and methods of the present invention allow short nucleotide oligomers to be utilized for uniquely identifying the compositions while enabling standard equipment to be utilized for sequencing the oligomers by extending the length of the oligomers during the initial stages of amplification.

(21) Effective and successful dispersal of the security marker composition is not especially limited. The polyacrylamide spheres may be distributed by many agricultural devices, such as standard broadcasters of fertilizers. The suitable dimensions of this equipment depends on the specific terrain and local conditions.

(22) The sticky emulsion may be distributed directly on the vegetation, preferably in bushy areas (see FIG. 4). The methods for dispersal are quite straightforward, and irrigation equipment such as standard water hoses, sprinklers or even water throwers may be employed.

(23) The sticky threads may be applied manually when used for applications when invisibility is of high priority. For outdoor dispersal it is more suitable to employ hurling equipment or slingshots to distribute the thin threads or fine gardening nets.

(24) While this invention has been particularly shown and described with reference to preferred embodiments, it will be understood to those skilled in the art that various changes in form and detail may be made without departing from the scope of the invention as defined by the appending claims.