The effect of RGD peptide-conjugated magnetite cationic liposomes on cell growth and cell sheet harvesting.

Tissue engineering requires novel technologies for establishing 3D constructs, and the layered method of culturing cell sheets (cell sheet engineering) is one potentially useful approach. In the present study, we investigated whether coating the culture surface with RGD (Arg-Gly-Asp) peptide-conjugated magnetite cationic liposomes (RGD-MCLs) was able to facilitate cell growth, cell sheet construction and cell sheet harvest using magnetic force without enzymatic treatment. To promote cell attachment, an RGD-motif-containing peptide was coupled to the phospholipid of our original magnetite cationic liposomes (MCLs). The RGD-MCLs were added to a commercially available 24-well ultra-low-attachment plate the surface of which comprised a covalently bound hydrogel layer that was hydrophilic and neutrally charged. A magnet was placed on the underside of the well in order to attract the RGD-MCLs to the surface of the well, and then NIH/3T3 cells were seeded into the well. Cells adhered to the bottom of the culture surface, which was coated with RGD-MCLs, and the cells spread and proliferated to confluency. After incubation, the magnet was removed and the cells were detached from the bottom of the plates, forming a contiguous cell sheet. Because the sheets contained magnetite nanoparticles, they could be harvested using a magnet inserted into the well. These results suggest that this novel methodology using RGD-MCLs and magnetic force, which we have termed 'magnetic force-based tissue engineering (Mag-TE)', is a promising approach for tissue engineering.