In-situ and real-time probing cellulase biosensor formation and its interaction with lignosulfonate in varied media

[Display omitted] •Whole process of film formation and interaction was monitored in situ and in real time.•Combined methodology of QCM-D and MP-SPR was employed.•Signals were interpreted with the aid of QTools and WinSpall.•Thickness, viscous and elastic moduli, and coupled solvent of each layer were characterized. It is a challenge to interpret the signals obtained by Quartz Crystal Microbalance (QCM) and Surface Plasmon Resonance (SPR) accompanied with in the significant changes of the density and/or refractivity of media. The work presented herein focuses on demonstrating a universal in-situ and real-time monitoring methodology for ultrathin film formation on gold chips in varied media. Biomimetic model cellulase/enzyme film was immobilized in-situ on gold surface of sensors, followed by revealing its interaction with lignosulphonate in the media changed from ethanol-based to aqueous ones. Combining the techniques of Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) and Multi-parametric Surface Plasmon Resonance (MP-SPR) along with respective software and models enabled us to precisely characterize the thickness, viscous and shear elastic moduli, and the coupled solvent for individual layer formed over the entire process, which are unachievable with conventional methods. The methodology provides real-time monitoring of filming process and offers us an in-situ qualify control approach to the biomimetic model films formed on different substrates including gold chip.