Immobilization of Solvatochromic Dyes on Transparent Cellulose Films: an Improved Method for the Study of Homeopathic Potencies.

Background: Highly diluted and succussed solutions (homeopathic potencies) have been shown to interact with a wide range of solvatochromic dyes based on changes in their UV-visible spectra. Studies so far have involved free dyes in solution, but there is a pressing need to find ways to investigate the potency-dye interaction using isolated dye molecules to ask more searching physico-chemical questions regarding the fundamental nature of potencies.

Aims and methods: The aims of the present study have been to look for ways to covalently immobilize solvatochromic dyes onto transparent cellulose films and hence be in a position to investigate dye-potency interactions without the complication of dye-dye interactions, including dye aggregation, which can occur with free dyes in solution.

Results: To date, a total of nine different dyes have been immobilized on cellulose films using epoxide activation of hydroxyl groups on the cellulose surface. Using this method, studies have begun looking at the time course of potency action on one of these immobilized dyes, Brooker's merocyanine. Results show that the interaction of Arsenicum 10M with this dye consists of three phases-an initial growth phase, a sustained plateau of interaction, and a final decline phase lasting several days.

Conclusion: A method has been developed that successfully immobilizes solvatochromic dyes onto transparent cellulose film. These films can then be used in a spectrophotometer to study at a much more detailed level how potencies interact with dyes compared with using free dyes in solution. Results indicate that the information gained in this way provides new insights regarding the fundamental nature of potencies. Specifically, studies using immobilized Brooker's merocyanine with Arsenicum 10M reveal that the lifetime of the potency is much longer than expected and that its action consists of three distinct phases, suggesting a resonant interaction with the dye. How resonant interaction might help to explain the clinical action of potencies is discussed.