A novel isophorone-derived fluorescent probe for detecting sulfite and the application in monitoring the state of hybridoma cells

In this work, a novel isophorone-derived fluorescent probe, ISOP-SFT, was developed for the detection of sulfite, and, for the first time, it was applied into monitoring the state of hybridoma cells. ISOP-SFT could exhibit a red-emission response to sulfite with the excitation at 455 nm. It also indicated practical advantages such as wide pH tolerance within 6.0-9.0 and high storage steadiness within at least one week. The linear range was relatively long (0-20 Eq) and reliable (Pearson's correlation coefficient: 0.9989), while Limit of Detection was determined as 0.0095 Eq (95 nM). For the selectivity, ISOP-SFT could distinguish sulfite from other analytes, and the response of ISOP-SFT towards sulfite was not seriously interfered in co-existence system. With low cytotoxicity, ISOP-SFT achieved monitoring both the exogenous and endogenous sulfite in living MCF-7 cells. As a novel attempt, ISOP-SFT was applied into monitoring the state of hybridoma cells, and associated with the quality control of producing antibodies. The result preliminarily inferred the positive correlation between the production efficiency of antibodies in hybridoma cells and the intracellular sulfite level, including the conditions of serum starvation, oxidative stress, severe hypoxia and endogenous induction. We hope that the information in this work could lead to new applications of fluorescent probes in biological industry in future.