Alendronate-Anionic Clay Nanohybrid for Enhanced Osteogenic Proliferation and Differentiation

BACKGROUND: Alendronate (AL), a drug for inhibiting osteoclast-mediated bone-resorption, was intercalated into an inorganic drug delivery nanovehicle, layered double hydroxide (LDH), to form a new nanohybrid, AL-LDH, with 1:1 heterostructure along the crystallographic C-axis. Based on the intercalation reaction strategy, the present AL-LDH drug delivery system (DDS) was realized with an enhanced drug efficacy of AL, which was confirmed by the improved proliferation and osteogenic differentiation of osteoblast-like cells (MG63). METHODS: The AL-LDH nanohybrid was synthesized by conventional ion-exchange reaction and characterized by powder X-ray diffraction (PXRD), high-resolution transmission electron microscopy (HR-TEM), and Fourier transform infrared (FT-IR) spectroscopy. Additionally, in vitro efficacy tests, such as cell proliferation and alkaline phosphatase (ALP) activity, were analyzed. RESULTS: The AL was successfully intercalated into LDH via ion-exchange reaction, and thus prepared AL-LDH DDS was X-ray single phasic and chemically well defined. The accumulated AL content in MG63 cells treated with the AL-LDH DDS nanoparticles was determined to be 10.6-fold higher than that within those treated with the intact AL after incubation for 1 hour, suggesting that intercellular permeation of AL was facilitated thanks to the hybridization with drug delivery vehicle, LDH. Furthermore, both in vitro proliferation level and ALP activity of MG63 treated with the present hybrid drug, AL-LDH, were found to be much more enhanced than those treated with the intact AL. This is surely due to the fact that LDH could deliver AL drug very efficiently, although LDH itself does not show any effect on proliferation and osteogenic differentiation of MG63 cells. CONCLUSION: The present AL-LDH could be considered as a promising DDS for improving efficacy of AL.

The Inhibitory Effect of Methotrexate-Layered Double Hydroxide (LDH) Hybrid on Osteosarcoma Cell Lines / 대한정형외과학회잡지

PURPOSE: The purpose of this study was to observe and analyze the effect of Methotrexate-Layered Double Hydroxide (LDH) hybrids on growth inhibition and the apoptosis of human osteosarcoma cell lines (SaOS-2, MG-63) and normal fibroblasts. MATERIALS AND METHODS: FITC-LDH hybrids were added to the cells and incubated for 2, 4, 6, and 8 hours. The samples were examined by fluorescence microscopy. SaOS-2 and MG-63 cells, and a normal fibroblast cell line (Detroit 551) were treated with 500 g/mL MTX and 500 g/mL MTX-LDH hybrids for 24, 48, 72, and 96 hours, respectively. The proliferation was measured by using the MTT assay. Apoptosis was determined by DNA fragmentation analysis. RESULTS: The hybrids with LDH entered the cells effectively in a time- and dose-dependent manner. The proliferation of SaOS-2 cells in a culture treated with 500 g/mL of MTX-LDH hybrids for 24 hours was significantly inhibited (37% more) compared to those treated with MTX. MG-63 cell growth was inhibited 20% more than SaOS-2 cell growth. However, the difference in the degrees of inhibition of cells treated with MTXLDH hybrid or with MTX alone reduced with time. DNA ladders appeared in cells treated with 500 g/mL MTX-LDH hybrid for 24 hours but not in those treated with MTX and LDH alone. CONCLUSIONS: The results of this study suggest that MTX-LDH hybrid more effectively enters cells and inhibits their proliferation than MTX alone.