Preparation and properties of a dual-function cellulose nanofiber-based bionic biosensor for detecting silver ions and acetylcholinesterase.

A dual-function cellulose nanofiber (CNF)-based bionic biosensor with good biocompatibility was developed for detecting Ag+ and acetylcholinesterase (AChE) by grafting deoxyribonucleic acid (DNA) onto CNF. The Ag+ ions captured by the biosensor acted as recognition sites for the detection of AChE. The CNF-based bionic biosensor (CNF-DNA) could detect Ag+ concentrations as low as 10-6 nM in the presence of interference metal ions (Hg2+, Ba2+, Cd2+, Mg2+, Mn2+, Pb2+, and Zn2+). DNA-template silver nanoclusters (DNA-AgNCs) were formed on the surface of CNF-DNA during the detection of Ag+ (CNF-DNA-AgNCs). This new strategy yielded CNF-DNA-AgNCs through the adsorption of Ag+ ions onto the cytosine base of the single-stranded DNA in CNF-DNA without the use of any additional reducer. Meanwhile, the CNF-DNA-AgNCs exhibited excellent sensitivity and selectivity for trace levels (0.053 mU/mL) of AChE in the presence of interference reagents. The novel strategy proposed in this paper may establish a foundation for further research on DNA-template AgNCs for developing biosensors and biomarkers for in vivo and in vitro detection.