Sensors

1. A composition for detecting the presence of a botulinum neurotoxin in a sample, the composition comprising:

a colloid formed from:

(a) a salt solution;

(b) charged particles suspended in the salt solution; and

(c) a cleavable coating on the charged particles,

wherein the cleavable coating comprises at least one SNAP-25, VAMP or syntaxin protein;

wherein the composition has a first color when the cleavable coating is present on the charged particles suspended in the salt solution; and

wherein the composition has a second color when the coating is cleaved.

2. The composition as claimed in claim 1 , wherein the first color is red and the second color is blue.

3. A method of producing a sensor for detecting the presence of botulinum neurotoxin in a sample, the method comprising:

(a) coating an electrically conductive substrate with a colloid formed from:

a salt solution,

charged particles suspended in the salt solution, and

a cleavable coating on the charged particles,

wherein the cleavable coating comprises at least one SNAP-25, VAMP or syntaxin protein,

wherein the composition has a first color when the cleavable coating is present on the charged particles suspended in the salt solution, and

wherein the composition has a second color when the coating is cleaved;

(b) providing a vessel in which the coating can be placed in contact with the sample and optionally other reagents; and

(c) providing a detection arrangement adapted to enable the detection of botulinum neurotoxin driven SNAP-25, VAMP or syntaxin cleavage events.

4. The method as claimed in claim 3 , wherein the detection arrangement comprises a detector and the method further comprises:

(d) coupling the detector to a display for displaying the presence, and optionally the quantity, of the botulinum neurotoxin in the sample.

5. A method of detecting the presence of botulinum neurotoxin in a sample, the method comprising:

(a) providing the composition of claim 1 ;

(b) contacting the sample with the composition; and

(c) detecting whether the composition undergoes a visual change of color from the first color to the second color.

6. The method as claimed in claim 5 , wherein the method further comprises the step of:

(d) quantifying the botulinum neurotoxin in the sample by detecting the number or quantity of SNAP-25, VAMP or syntaxin proteins which have been cleaved by the contacting step.

7. The method as claimed in claim 5 , detecting whether the composition undergoes a visual change of color from the first color to the second color comprises detecting and measuring the difference in absorbance profile of the composition between 525-670 nm relative to a control absorbance profile.

8. The method as claimed in claim 5 , wherein the charged particles are negatively charged.

9. A detection kit for detecting the presence of a botulinum neurotoxin in a sample, the kit comprising:

(i) a colloid formed from:

(a) a salt solution;

(b) charged particles suspended in the salt solution; and

(c) a cleavable coating on the charged particles,

 wherein the cleavable coating comprises at least one SNAP-25, VAMP or syntaxin protein;

 wherein the composition has a first color when the cleavable coating is present on the charged particles suspended in the salt solution; and

 wherein the composition has a second color when the coating is cleaved; and

(ii) a color scale for assessing a visual color profile of a mixture of the salt solution and the sample between 525-670 nm.

10. The kit as claimed in claim 9 , wherein the electrically conductive and negatively charged particles are coated with two or all of SNAP-25, VAMP and syntaxin proteins.

11. The kit as claimed in claim 9 , wherein the charged particles are negatively charged.

12. The composition as claimed in claim 1 , wherein the charged particles are negatively charged.

13. The composition as claimed in claim 12 , wherein the charged particles are electrically conductive.

14. The kit as claimed in claim 11 , wherein the charged particles are electrically conductive.