A boronate-modified renewable nanointerface for ultrasensitive electrochemical assay of cellulase activity

The saccharification of cellulosic biomass to produce biofuels and chemicals is one of the most promising industries for green-power production and sustainable development. Cellulase is the core component in the saccharification process. Simple and efficient assay method to determine cellulase activity in saccharification is thus highly required. In this work, a boronate-affinity surface based renewable and ultrasensitive electrochemical sensor for cellulase activity determination has been fabricated. Through boronate-sugar interaction, celluloses are attached to the electrode surface, forming the cellulose nano-network at the sensing interface. Cellulase degradation can lead to the variation of electrochemical impedance. Thus, electrochemical impedance signal can reflect the cellulase activity. Importantly, via fully utilizing the boronate-affinity chemistry that enables reversible fabrication of cellulose nano-network, a renewable sensing surface has been firstly constructed for cellulase activity assay. Thanks to interfacial diffusion process of electrochemical sensor, the product inhibitory effect in the cellulase activity assays can be circumvented. The proposed electrochemical sensor is ultrasensitive for label-free cellulase activity detection with a very simple fabrication process, showing great potential for activity screen of new enzymes in saccharification conversion.