Sensitive and Label-Free Optical Fiber Biosensor Based on ZIF-8/Lipase Composite Material and Its Application in Tributyrin Detection

As a low-density lipoprotein, tributyrin plays a vital role in food safety and human health. In this work, we first proposed a novel high-performance tributyrin sensor made by supporting zeolitic imidazolate framework-8 (ZIF-8) and lipase onto the optic fiber sensor based on the surface plasmon resonance (SPR) principle. After adsorption of lipase within the ZIF-8 framework, through a rapid aqueous synthesis method, a thin and dense ZIF-8 film can be uniformly formed and stably and tightly bonded to the surface of the optical fiber sensor. ZIF-8 is one of the metal–organic frameworks (MOFs), which not only has the high porosity and specific surface area of MOFs, but also shows good affinity with lipase. The experimental results show that the proposed sensor can achieve the specific detection of tributyrin in the linear range of 0.1–3 mM, the sensitivity is 14.75 nm/mM, with a detection limit of 0.096 mM. The sensor proposed in this article for the first time using ZIF-8/lipase composite material to detect tributyrin has an accuracy of more than 83% in sample detection at the range of 0.1–3 mM. In addition, the stability test of the proposed sensor is as good as 0.47 nm, and the selectivity (in the presence of glycine, acetylcholine, glucose, and urea) of the sensor was analyzed. The sensor proposed in this article has the advantages of a low sample consumption of
$100~\mu \text{L}$
, high sensitivity, simple structure, and label-free measurement. This method provides a new route for the rapid and reliable detection of tributyrin, which has potential applications in medical research and clinical diagnosis.