Observation of Py-12-O-2-DMA fluorescence in sodium dodecyl sulfate aqueous solution

Abstract

Various fluorescent molecules have been developed for cell observation using a fluorescence microscope. There is also a need to develop magnetic sensitive fluorescent molecules to be used in research to determine whether cells are affected by magnetic field effect. Pyrene-(CH2)12-O-(CH2)2-N, N-dimethylaniline (Py-12-O2-DMA) is one of the molecules synthesized for the research of the magnetic field effect. Py-12-O-2-DMA is a structure in which pyrene, a fluorescent molecule that acts as an electron acceptor molecule, and N, Ndimethylaniline, which acts as an electron donor molecule, are connected by an alkyl chain consisting of 12 carbons. Py-12-O-2-DMA with this structure forms exciplex and RIP through photo-induced electron transfer. In non-polar solvents, the intensity of fluorescence emitted by the exciplex is changed by the magnetic field effect. Due to charge recombination of the non-radiative product RIP, magnetic field effect can be observed through the change in the exciplex fluorescence intensity. However, water is an extremely strong polar solvent and the same characteristic of the molecules that make up Py-12-O-2-DMA is that they all have very low solubility in water. The way to dissolve molecules with low solubility in water is to use a surfactant. Surfactants with hydrophilic groups and hydrophobic groups create a structure called micelles above the critical micelle concentration (CMC). As insoluble substances exist inside micelles made of hydrophobic groups, they dissolve in water, which is called solubilization. Solubilization of insoluble substances using surfactants is a well-known method in everyday life, such as washing clothes with surfactants to remove oil or oil-soluble pigments from fabric. Several studies have already been reported on the physical properties of surfactants observed through the emission spectrum of several organic fluorescent molecules. Also, many studies have been conducted using micelles for the application of organic fluorescent molecules. In this study, Py-12-O-2-DMA is dissolved in micelles using sodium dodecyl sulfate, a surfactant, and the fluorescence spectrum is measured to determine whether the magnetic field effect appears in water.