Nanosheet-Decorated Cu ₂ S Hollow Nanocubes Performing Ultrasensitive and Fast Biosensing of Broth Glycerol for Fermentation Monitoring

Glycerol is an attractive alternative carbon source for microbial fermentations due to its low cost and high degree of reduction, and its concentration should be precisely monitored to enable product concentrations on the order of tens of grams per liter under advanced fermentation conditions. However, current analytical methods for quantifying glycerol are always hampered by bulky instrumentation and complex pretreatment procedures due to large fluctuations in glycerol concentration caused by numerous coexisting substances in broth. To address this challenge, we have proposed an ultrasensitive and ultrafast electrochemical biosensor constructed by the nanosheet-decorated hollow Cu2S nanocubes to achieve direct, accurate quantification of glycerol in untreated samples. This hollow cubic architecture was created through a precursor-sacrifice strategy, which can greatly shorten electron-transfer pathways and provide abundant enzyme immobilization sites for remarkable signal amplification and acceleration. This biosensor enabled us to finish a detection within only 9 s and exhibited an ultrawide linear response range from 0.005 to 0.295 M without any pretreatment of the original broth. This specific biosensing technique is promising for providing a practical solution for fast, real-time glycerol monitoring, thereby supporting the improvement of the automation and unattended operation for the development of modern industrial fermentation.