Filice Fraser P, Henderson Jeffrey D, Li Michelle S M, Ding Zhifeng
Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7, Canada.
ACS Omega. 2019 Jan 31;4(1):2142-2151. doi: 10.1021/acsomega.8b02113. Epub 2019 Jan 28.
Cr(III) is often regarded as a trace essential micronutrient that can be found in many dietary supplements due to its participation in blood glucose regulation. However, increased levels of exposure have been linked to adverse health effects in living organisms. Herein, scanning electrochemical microscopy (SECM) was used to detect variation in membrane permeability of single cells (T24) resulting from exposure to a trivalent Cr-salt, CrCl. By employing electrochemical mediators, ferrocenemethanol (FcMeOH) and ferrocenecarboxylic acid (FcCOO), initially semipermeable and impermeable, respectively, complementary information was obtained. Three-dimensional COMSOL finite element analysis simulations were successfully used to quantify the permeability coefficients of each mediator by matching experimental and simulated results. Depending on the concentration of Cr(III) administered, three regions of membrane response were detected. Following exposure to low concentrations (up to 500 μM Cr(III)), their permeability coefficients were comparable to that of control cells, 80 μm/s for FcMeOH and 0 μm/s for FcCOO. This was confirmed for both mediators. As the incubation concentrations were increased, the ability of FcMeOH to permeate the membrane decreased to a minimum of 17 μm/s at 7500 μM Cr(III), while FcCOO remained impermeable. At the highest examined concentrations, both mediators were found to demonstrate increased membrane permeability. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cell viability studies were also conducted on Cr(III)-treated T24 cells to correlate the SECM findings with the toxicity effects of the metal. The viability experiments revealed a similar concentration-dependent trend to the SECM cell membrane permeability study.
由于参与血糖调节，三价铬（Cr(III)）常被视为一种微量必需营养素，在许多膳食补充剂中都能找到。然而，接触水平的增加与生物体的不良健康影响有关。在此，扫描电化学显微镜（SECM）被用于检测暴露于三价铬盐CrCl后单细胞（T24）膜通透性的变化。通过使用电化学介质，分别为最初半透性的二茂铁甲醇（FcMeOH）和不透性的二茂铁羧酸（FcCOO），获得了互补信息。通过匹配实验和模拟结果，成功地使用三维COMSOL有限元分析模拟来量化每种介质的渗透系数。根据所施用的Cr(III)浓度，检测到膜反应的三个区域。暴露于低浓度（高达500 μM Cr(III)）后，它们的渗透系数与对照细胞相当，FcMeOH为80 μm/s，FcCOO为0 μm/s。两种介质均得到证实。随着孵育浓度的增加，FcMeOH透过膜的能力降低，在7500 μM Cr(III)时降至最低17 μm/s，而FcCOO仍不透性。在所检测的最高浓度下，发现两种介质的膜通透性均增加。还对经Cr(III)处理的T24细胞进行了3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐细胞活力研究，以将SECM的结果与金属的毒性效应相关联。活力实验揭示了与SECM细胞膜通透性研究相似的浓度依赖性趋势。
