Nanoporous Alumina Membranes as Diffusion Controlling Systems

This work describes the use of nanoporous alumina membranes for the diffusion of crystal violet molecules, encapsulated in the micelles of sodium dodecylsulfate (SDS), through pores ranging between 20 and 200 nm in diameter. The encapsulation of the crystal violet in SDS micelles is necessary in order to enlarge the size of the molecules to such an extent that the pore size becomes a speed-controlling function. Superior results were obtained when the membrane-containing capsule is placed into a water-filled beaker, and carefully moved by means of a "tipping bridge" in order to prevent diffusion problems in the capsule. Free crystal violet was liberated following diffusion due to the low SDS concentration in the aqueous solution, which was far below the critical micelle concentration (CMC). Micelle formation and encapsulation of crystal violet is shown by UV-visible and fluorescence spectroscopies. The experiments described herein serve as an exploratory test for developing novel drug delivery systems.

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