Rapid detection of serum calcium based on supramolecular aggregates of a cationic perylene in vitro

Abstract

The steady-state level of serum calcium is of great significance to human body. Accurate and rapid detection of serum calcium is a crucial component of clinical diagnosis and blood calcium census. Current detection of Ca2+ in living environment mainly focus on intracellular imaging, and there are few probes appropriate for serum calcium detection. In this work, we designed a fluorescence sensing system based on the indicator displacement assays (IDAs) strategy using supramolecular complex formed by 3,4,9,10-tetra-(4-trimethylaminobutoxy-carbonyl)-perylene (PBTMA) and casein phosphopeptides (CPPs). Due to the synergistic effect of non-covalent interactions, the complex can be induced by Ca2+ to disintegrate, thus realizing the visual and rapid detection of serum calcium. The quantitative range is 0.01–3.0 mM, while the limit of detection (LOD) and the visual detection limit are 8.4 μM and 0.1 mM, respectively. This method features good stability, selectivity and anti-interference. It can be used for serum samples (recovery rate: 103.4%–106.3%; relative standard deviation (RSD): 2.21%–3.46%). Furthermore, a portable device for rapid serum calcium measurement was designed, which could substantially improve the applicability of this method. To our knowledge, this is the first organic small molecule fluorescent probe capable of application in the range of serum calcium concentrations.