Abstract：
Intracellular calcium ion detection is of great significance for understanding the cell metabolism and signaling pathways. Most of the current ionic sensors either face the size issue or sensitivity limit for the intracellular solution with high background ion concentrations. In this paper, we proposed a calmodulin (CaM) functionalized nanopore for sensitive and selective Ca2+ detection inside living cells. A salt gradient was created when the nanopore sensor filled with a low concentration electrolyte was in contact with a high background concentration solution, which enhanced the surface charge-based detection sensitivity. The nanopore sensor showed a 10 × sensitivity enhancement by application of a 100-fold salt gradient, and a detection limit of sub nM. The sensor had a wide detection range from 1 nM to 1 mM, and allowed for quick calcium ion quantification in a few seconds. The sensor was demonstrated for intracellular Ca2+ detection in A549 cells in response to ionomycin.
摘要：
细胞内钙离子检测对于了解细胞代谢和信号通路具有重要意义。对于具有高背景离子浓度的细胞内溶液,当前大多数离子传感器面临尺寸问题或灵敏度限制。在本文中,我们提出了一种钙调蛋白（CaM）功能化的纳米孔，用于活细胞内敏感和选择性的Ca2+检测。当填充有低浓度电解质的纳米孔传感器与高背景浓度溶液接触时,产生盐梯度。这增强了基于表面电荷的检测灵敏度。通过施加100倍的盐梯度，纳米孔传感器显示出10倍的灵敏度增强，和亚nM的检测极限。该传感器具有从1nM到1mM的宽检测范围,并允许在几秒钟内快速定量钙离子。该传感器被证明用于A549细胞中响应于离子霉素的细胞内Ca2+检测。
