Method of determining crystallization

1. A method for determining a crystallisation in a material of interest in a localised environment, said method comprising:

(A) providing a sensor device having an optical waveguide capable of exhibiting a measurable response to a change in the localised environment caused by the crystallisation in the material of interest therein;

(B) introducing the material of interest into the localised environment;

(C) inducing the crystallisation in the material of interest;

(D) generating an output from the optical waveguide over a temporal range;

(E) measuring the response of a characteristic of the output over the temporal range; and

(F) relating the response of the characteristic of the output over the temporal range to the crystallisation.

2. A method as claimed in claim 1 wherein step (D) comprises: irradiating the optical waveguide with electromagnetic radiation to generate an output over a temporal range.

3. A method as claimed in claim 1 wherein step (C) comprises: imposing a condition such as to induce the crystallisation.

4. A method as claimed in claim 3 further comprising: (G) associating the crystallization with the condition.

5. A method as claimed in claim 3 wherein the condition comprises at least one of a chosen temperature, pressure, acidity, solvent, humidity and a combination thereof.

6. A method as claimed in claim 3 wherein step (C) is preceded by the step of:

(CO) sequentially imposing variable conditions on the localised environment until the condition in the localised environment is such as to induce the crystallisation.

7. A method as claimed in claim 1 wherein the material of interest contains a biological molecule.

8. A method as claimed in claim 1 wherein the material of interest comprises a protein.

9. A method as claimed in claim 1 wherein the sensor device comprises an interferometric sensor device.

10. A method as claimed in claim 9 wherein the optical waveguide has a structure which includes:

either (a) one or more sensing layers capable of inducing in a secondary waveguide a measurable response to a change in the localised environment caused by the crystallisation

or (b) a sensing waveguide capable of exhibiting a measurable response to a change in the localised environment caused by the crystallisation.

11. A method as claimed in claim 9 wherein the optical waveguide has a structure which includes: either (a) one or more sensing layers capable of inducing in a secondary waveguide a measurable response to a change in the localised environment caused by the crystallisation and an inactive secondary waveguide in which the sensing layer is incapable of inducing a measurable response to a change in the localised environment caused by the crystallisation or (b) a sensing waveguide capable of exhibiting a measurable response to a change in the localised environment caused by the crystallisation and an inactive waveguide substantially incapable of exhibiting a measurable response to a change in the localised environment caused by the crystallisation.

12. A method as claimed in claim 10 wherein each of the sensing waveguide or secondary waveguide of the sensor component is a planar waveguide.

13. A method as claimed in claim 1 wherein the crystallisation contributes to a change in the effective refractive index of the optical waveguide.

14. A method as claimed in claim 9 wherein the characteristic of the output is a non-positional characteristic.

15. A method as claimed in claim 14 wherein the nonpositional characteristic is contrast of a pattern of interference fringes.

16. A method as claimed in claim 2 wherein step (D) is carried out with electromagnetic radiation in TM mode.

17. A method as claimed in claim 2 wherein step (D) is carried out with electromagnetic radiation in TE mode.

18. A method as claimed in claim 10 wherein the sensor device further comprises: means for intimately exposing at least a part of the (or each) sensing layer or the sensing waveguide of the optical waveguide, said means having a volume of 50 microlitres or less.

19. A method as claimed in claim 1 wherein step (D) comprises: generating an output from the optical waveguide on at least two occasions over a temporal range.

20. A method as claimed in claim 19 wherein step (D) comprises: generating an output from the optical waveguide continuously over a temporal range.

21. A method as claimed in claim 1 , wherein the change of an optical property comprises a change of an optical property of the waveguide.

22. A method as claimed in claim 21 , wherein the change of the optical property of the waveguide comprises a change in the proportion of an electromagnetic radiation which is lost during propagation of the electromagnetic radiation along the waveguide.

23. A method as claimed in claim 1 , wherein the sensor comprises an interferometric sensor.

24. A method as claimed in claim 23 , wherein the sensor further comprises a reference waveguide.