Folic acid modified clay/polymer nanocomposites for selective cell adhesion

A folic acid (FA) modified poly(epsilon-caprolactone)/clay nanocomposite (PCL/MMT-(CH₂CH₂OH)₂-FA) resulting in selective cell adhesion and proliferation was synthesized and characterized as a cell culture and biosensing platform. For this purpose, first the FA modified clay (MMT-(CH₂CH₂OH)₂-FA) was prepared by treating the organo-modified clay, Cloisite 30B [MMT-(CH₂CH₂OH)₂] with FA in chloroform at 60 °C. Subsequent ring opening polymerization of ε-caprolactone in the presence of tin octoate (Sn(Oct)₂) using MMT-(CH₂CH₂OH)₂-FA at 110 °C resulted in the formation of MMT-(CH₂CH₂OH)₂-FA with an exfoliated clay structure. The structures of intermediates and the final nanocomposite were investigated in detail by FT-IR spectral analysis and DSC, TGA, XRD, SEM and AFM measurements. The combination of FA, PCL and clay provides a simple and versatile route to surfaces that allows controlled and selective cell adhesion and proliferation. FA receptor-positive HeLa and negative A549 cells were used to prove the selectivity of the modified surfaces. Both microscopy and electrochemical sensing techniques were applied to show the differences in cell adherence on the modified and pristine clay platforms. This approach is expected to be adapted into various bio-applications such as 'cell culture on chip', biosensors and design of tools for targeted diagnosis or therapy.