Viable but nonculturable cells used in biosensor fabrication for long-term storage stability

In this paper, we first reported the viable but nonculturable (VBNC) cells used for fabricating biosensor. The organic-inorganic hybrid material composed of silica and the grafting copolymer of poly(vinyl alcohol) and 4-vinylpyridine (PVA-g-P(4-VP)) was used to immobilize microbial cells for biosensor fabrication. The VBNC cells were formed after the hybrid material dried, showing the cell walls were sacrificed. With the intracellular enzymes as core and the "sacrificed" cell walls as shell, the present VBNC cells maybe considered as a core/shell structure. The extracellular material worked as the scaffold for core/shell structure. The core/shell structure and the scaffold structure were demonstrated by single-cell level image analysis using confocal laser scanning microscopy (CLSM). The electrochemical method was adopted for further examining the enzyme activity of VBNC cells. The VBNC cells did not need nutrient treatment and other physicochemical factors for cell growth, which is a significant contribution for storing biosensor. A glucose-glutamic acid biosensor fabricated by the VBNC cells exhibited long-term storage stability for 100 days.