Ultra-stable zeolites--a tool for in-cell chemistry

Ultrastable zeolite particles were used as vehicles to carry low molecular bio-active substances and macromolecules as proteins into viable cells. Zeolite particles that can be used for internalisation by phagocytosis were obtained from the non-sedimenting fraction of a commercially available zeolite preparation after 1 x g sedimentation. Protein adsorbed on the zeolite surface was shown to enter the endosomal pathway after phagocytosis and could be cleaved by the endosomal proteases. As a model of a low molecular weight bio-active molecule, the inhibitor of the cellular synthesis of nitrogen oxide, N-nitro-L-arginine methyl ester (L-NAME), was used. A partial inhibition of the cellular NO production was shown after utilizing zeolites as vehicles to introduce the inhibitor into the cells. A targeting of the intra-cellular enzymes that was at least 10 times more efficient was obtained by the use of zeolites as a carrier of the inhibitor, as opposed to addition of the inhibitor to the culture medium.