Huang Shao-Hong, Zhang Jian, Li Yun, Rong Jian, Wu Zhong-Kai
Department of Cardiothoracic Surgery, Third Affiliated Hospital, Guangzhou, China.
N Am J Med Sci. 2013 Feb;5(2):149-52. doi: 10.4103/1947-2714.107540.
Microdialysis is a specific and local sampling method to collect free molecules from the extracellular fluid, however, there are no reports on time delay issues of microdialysis applications.
This study was to check the time gap between the start of target molecule changes in detected fluid and corresponding stable concentration formation in the sampled dialysate.
A designated microdialysis system for free calcium ion was set up in vitro and perfused with saline. The dialysate was diluted synchronously, and collected in a vial every 10 min. The free calcium concentration [Ca++] of the sample was measured by an atomic absorption spectrophotometer. A signal-switching method was introduced to mimic the target molecule [Ca++] changes in the detected fluid, standard calcium solution and saline.
There was a notable lag in dialysates [Ca++] for both uprising and down going course in spite of instant switching between the detected fluids. The recovery time (RT) of the microdialysis system was extrapolated to be 20 min for [Ca++] detection.
With 10 min sampling interval, [Ca++] time delay of the microdialysis system existed, and could not be estimated precisely beforehand. The signal-switching method was applicable for RT calibration in vitro with a dedicated microdialysis system.
微透析是一种从细胞外液中收集游离分子的特异性局部采样方法，然而，关于微透析应用中的时间延迟问题尚无报道。
本研究旨在检测检测液中目标分子变化开始与采样透析液中相应稳定浓度形成之间的时间间隔。
在体外建立了一个用于游离钙离子的指定微透析系统，并用盐水灌注。透析液同步稀释，每10分钟收集到一个小瓶中。用原子吸收分光光度计测量样品的游离钙浓度[Ca++]。引入信号切换方法来模拟检测液、标准钙溶液和盐水中目标分子[Ca++]的变化。
尽管检测液之间即时切换，但透析液[Ca++]在上升和下降过程中均存在明显滞后。微透析系统对[Ca++]检测的恢复时间（RT）外推为20分钟。
在10分钟采样间隔下，微透析系统存在[Ca++]时间延迟，且无法预先精确估计。信号切换方法适用于在体外使用专用微透析系统进行RT校准。
