Inorganic Layered Nanomaterial for Potential Cancer Therapy

Over the past decade the application of nanotechnology for the delivery of chemotherapeutic drugs has been an increasingly active area of research, particularly for cancer treatment. The clinical efficacy of currently used chemotherapeutic agents is limited due to low selective distribution, which causes adverse side effects and fast elimination in vivo. In addition, a high percentage of the intermediate- and high-risk tumor patients develop metastatic disease resistant to chemotherapy and die of the disease. Therefore, special attention has been paid to developing new effective delivery systems that selectively target the affected area and reduce the side effects due to the toxicity of commonly used treatments. Among the new potential delivery systems are the inorganic layered nanomaterials (ILN). One of them is zirconium bis(monohydrogen orthophosphate) monohydrate (Zr(HPO₄)2·H₂O, α-ZrP), the best characterized zirconium phosphate (ZrP).  The highly hydrated phase of the layered ZrP, known as the θ-phase (θ-ZrP), is an acidic ion exchanger that has been used for the immobilization of several photo-, bio- and redox-active compounds. Among these compounds is a metallocene dichloride known as molybdocene dichloride (MDC), which has been proposed and investigated as a potential anticancer drug. We use θ-ZrP as a host to intercalate MDC by direct ion exchange and characterize the intercalated material for possible applications as an anticancer drug carrier.     The direct intercalation reaction of the MDC into θ-ZrP was performed. The intercalated materials were characterized using IR spectroscopy, X-ray powder diffraction (XRPD), UV-vis spectrophotometry, SEM-EDX, thermogravimetric analysis (TGA), and NMR spectroscopy to confirm the presence of MDC inside the layers of ZrP. The XRPD data indicates that a new intercalated phase with expanded interlayer distances of 11.0 Å was obtained; TGA indicates up to 64% loading. IR spectroscopy confirms the presence of the cyclopentadienyl bearing metallocene in the layers of ZrP. We will present the characterization of the unintercalated metallocene derivative as well as those of the intercalated materials.