Inorganic-Polymer Core-Shell with Gadolinium Complex for Switching on/off CT/MRI Dual Detection System of Cancer Cells upon pH Change

Core shell type of CT/MRI contrasting agent nano-delivery system is successfully demonstrated via utilizing continuous fusion of reverse micelles with one-pot fashioned reaction that is easy and economically favorable way. The system consists of layered double hydroxides (LDHs) as outermost shells for effective cellular uptake toward cancer cells and chitosan/gelatin biopolymer composites as second shells to immobilize Gd-DTPA complexes as the CT/MRI contrasting agent in the core. To prove cancer cell targeting ability by LDHs, cellular uptake efficacy is measured with fluorescence assisted cell sorting (FACS) and confocal microscopy. Besides, the delivery system shows the possibility to release contrasting agents with switching on/off fashion depending on pH conditions. Especially, it is found that the release of dye molecules is almost prohibited at physiologically neutral condition (release-off) and the dye seems to burst out from the systems at lysosomal environment (release-on state). The accelerated release of Gd-DTPA complexes in the lysosomal conditions indicates the delivery system can be utilized for CT/MRI contrasting systems with highly selective and senstive ways upon changing envriromental conditions. As a result, high performances of CT/MRI contrasting effect are achieved at acidic condition; we obtaine 508 HU for CT and 6.6 of r₁ relexivity for MRI respectively.