Screen‐printing of nanocube‐based flexible microchips for the precise biosensing of ethanol during fermentation

The real‐time and full concentration analysis of ethanol during the fermentation reaction allows the precise control of the microbial metabolism to promote the conversion rate; however, only few techniques can directly detect the fermentation broth without pretreatment. To address this issue, a screen‐printed biosensing microchip (SPBM) was proposed to analyze the ethanol concentration in fermentation, relying on designing a well‐defined nanocubic structure of an Au nanoparticles/nickel hexacyanoferrate nanocomposite. This nanocomposite was then made into a printing ink for the direct fabrication of a SPBM. The as‐prepared microchip exhibits an ultrahigh electrocatalysis on nicotinamide adenine dinucleotide with a high sensitivity of 96.2 ± 2.9 μA·mM −1 ·cm −2 . Moreover, after the immobilization of alcohol dehydrogenase, the accurate and rapid monitoring of the ethanol concentration during the real fermentation reaction can be realized within an ultrawide linear range of 0.1–10 M in the broth without any pretreatment.