Cellulosic biosensor chips for monitoring adsorptive interaction of rubisco protein with cellulose using SPR

摘要

Cellulosic films were prepared by spin-coating a nano-layer of cellulose from an organic solvent onto gold substrates. The cellulose-coated substrates were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and surface plasmon resonance (SPR). Rubisco protein adsorptive interaction with the spin-coated cellulosic surfaces was monitored using SPR. The results have demonstrated that rubisco uptake by the spin-coated cellulosic films is minimal relative to other non-cellulosic films. The results have also revealed that rubisco uptake by the spin-coated cellulosic films is inconsistent, most likely due to the interference of the SPR reflectivity signal (i.e. measurement accuracy) by the swelling of the thick (similar to 30 nm on dry basis) films. This inconsistency problem was resolved by preparing ultrathin films (similar to 2.5 nm) of cellulose via the self-assembly of cellulose onto the SPR biosensor chips. The self-assembly was achieved by attaching disulphide functional group to the cellulose molecules through the chemical coupling with alpha-lipoic acid.