Photodynamic dye adsorption and release performance of natural zeolite

Abstract

Clinoptilolite type of zeolite (CZ) is a promising material for biomedicine and pharmaceutics due to its non-toxicity, thermal stability, expanded surface area, and exceptional ability to adsorb various atoms and organic molecules into micropores. Using multiphoton microscopy, we demonstrated that individual CZ particles produce two-photon excited luminescence and second harmonic generation signal at femtosecond laser excitation, and adsorb photo-dynamically active dyes such as hypericin and methylene blue. Furthermore, the release of hypericin from CZ pores in the presence of biomolecules is shown, and CZ can be considered as an effective material for drug delivery and controlled release in biological systems. The results may open new perspectives in application of CZ in biomedical imaging, and introducing of the optical approaches into the clinical environment.

Natural zeolite for adsorbing and release of functional materials

“…A completely different pattern was observed when a droplet of nonadsorbing fluorescein was added to the slide. 16 In this case, TPEL of fluorescein molecules has roughly uniform distribution, and CZ particles do not accumulate anionic fluorescein molecules in contrast to cationic MB, and SHG radiation from CZ particles is not quenched by fluorescein molecules. 16 Similar multiphoton imaging showed that CZ effectively adsorbed photodynamically active HYP from aqueous solutions.…”

“…16 In this case, TPEL of fluorescein molecules has roughly uniform distribution, and CZ particles do not accumulate anionic fluorescein molecules in contrast to cationic MB, and SHG radiation from CZ particles is not quenched by fluorescein molecules. 16 Similar multiphoton imaging showed that CZ effectively adsorbed photodynamically active HYP from aqueous solutions. Taking into account the sizes of the used dyes, one can make preliminary conclusion that the mesoporosity, negative charge of CZ, and hydrophobicity of dyes play main role in adsorption processes in CZ-dye systems.…”

“…34 Microporous CZ particles, as more universal transporter for systemic application of HYP, was suggested and quantitatively investigated previously. 16 Absorption and fluorescence spectra of HYP strongly depend on molecular environments. Using this HYP feature, the rate of release of HYP from CZ particles in the presence of biomolecules was measured.…”

“…In addition, multiphoton imaging allowed to measure sizes of CZ microparticles and estimate upper limit of the diameter of nanosized CZ particles. 16…”

“…Recently, the first effort of multiphoton imaging of CZ nano/microparticles has been performed, and a method of quantitative study of loading and release of photodynamic dyes by nano/microsized CZ particles using multiphoton microscopy (MPM) and optical spectrometry has been suggested. 16 Here we propose a new, more general method for quantification of the adsorbed dye release, and perform more detailed investigation of the release of a natural photodynamic pigment hypericin from CZ nano/ microparticles.…”