Preparation of fluorescently and biologically active chain-like chitosan nanocomposite and its use in separating MBP-tagged proteins and as fluorescent tracer of tobacco

Chain-like chitosan-sodium tripolyphosphate (CS-TPP) nanocomposite was prepared by an aqueous solution route. Then fluorescently active 6-carboxyl luciferin (6-FAM) was modified onto CS-TPP surface to afford CS-TPP-6-FAM nanocomposite (CS-TPP-6-FAM) with fluorescent activity. Onto the surface of CS-TPP-6-FAM was grafted bioactive carboxymethyl β-cyclodextrin (CβCD) to obtain CS/TPP/FAM/CβCD that can separate maltose binding protein tagged (MBP-tagged) fusion proteins from E. coli lysate. Findings demonstrate that CS-TPP-6-FAM-CβCD has an average diameter of 22 nm and a chain length of 70 nm. Its adsorption kinetic data can be described by Langmuir isotherm equation and the pseudo 2nd kinetic model, corresponding to high protein binding capacity for MBP-tagged PYL3. Furthermore, CS-TPP-6-FAM-CβCD dispersed in Hoagland nutrient solution can be adsorbed by tobacco through vascular bundle channels. Therefore, CS-TPP-6-FAM-CβCD could have promising applications in separating MBP-tagged fusion proteins from E. coli lysate and in monitoring the growth of plants as the fluorescent tracer.