Abstract
INTRODUCTION AND OBJECTIVE: Precisely and sensitively diagnosing diseases especially early and accurate tumor diagnosis in clinical magnetic resonance (MR) scanner is a highly demanding but challenging task. Gadolinium (Gd) chelate is the most common T (1) magnetic resonance imaging (MRI) contrast agent at present. However, traditional Gd-chelates are suffering from low relaxivity, which hampers its application in clinical diagnosis. Currently, the development of nano-sized Gd based T (1) contrast agent, such as incorporating gadolinium chelate into nanocarriers, is an attractive and feasible strategy to enhance the T (1) contrast capacity of Gd chelate. The objective of this study is to improve the T (1) contrast ability of Gd-chelate by synthesizing nanoparticles (NPs) for accurate and early diagnosis in clinical diseases. METHODS: Reverse microemulsion method was used to coat iron oxide (IO) with tunable silica shell and form cores of NPs IO@SiO(2) at step one, then Gd-chelate was loaded on the surface of silica-coated iron oxide NPs. Finally, Gd-based silica coating magnetite NPs IO@SiO(2)-DTPA-Gd was developed and tested the ability to detect tumor cells on the cellular and in vivo level. RESULTS: The r (1) value of IO@SiO(2)-DTPA-Gd NPs with the silica shell thickness of 12 nm was about 33.6 mM(-1)s(-1), which was approximately 6 times higher than Gd-DTPA, and based on its high T (1) contrast ability, IO@SiO(2)-DTPA-Gd NPs could effectively detect tumor cells on the cellular and in vivo level. CONCLUSION: Our findings revealed the improvement of T (1) relaxation was not only because of the increase of molecular tumbling time caused by the IO@SiO(2) nanocarrier but also the generated magnetic field caused by the IO core. This nanostructure with high T (1) contrast ability may open a new approach to construct high-performance T (1) contrast agent.