Chen Sisi, Yang Qingbo, Xiao Hai, Shi Honglan, Ma Yinfa
Department of Chemistry, Missouri University of Science and Technology, Rolla, MO, 65409, USA.
Center for Single Nanoparticle, Single Cell, and Single Molecule Monitoring, Missouri University of Science and Technology, Rolla, MO, 65409, USA.
Sens Actuators B Chem. 2017 Mar 31;241:398-405. doi: 10.1016/j.snb.2016.10.079. Epub 2016 Oct 18.
Biological studies of tissues and cells have enabled numerous discoveries, but these studies still bear potential risks of invalidation because of cell heterogeneity. Through high-accuracy techniques, recent studies have demonstrated that discrepancies do exist between the results from low-number-cell studies and cell-population-based results. Thus the urgent need to re-evaluate key principles on limited number of cells has been provoked. In this study, a novel designed dual-core fiber-optic pH micro-probe was fabricated and demonstrated for niche environment pH sensing with high spatial resolution. An organic-modified silicate (OrMoSils) sol-gel thin layer was functionalized by entrapping a pH indicator, 2', 7'-Bis (2-carbonylethyl)-5(6)-carboxyfluorescein (BCECF), on a ~70 μm sized probe tip. Good linear correlation between fluorescence ratio of I/I and intercellular pH values was obtained within a biological-relevant pH range from 6.20 to 7.92 (R = 0.9834), and with a pH resolution of 0.035 ± 0.005 pH units. The probe's horizontal spatial resolution was demonstrated to be less than 2mm. Moreover, the probe was evaluated by measuring the localized extracellular pH changes of cultured human lung cancer cells (A549) when exposed to titanium dioxide nanoparticles (TiO NPs). Results showed that the probe has superior capability for fast, local, and continual monitoring of a small cluster of cells, which provides researchers a fast and accurate technique to conduct local pH measurements for cell heterogeneity-related studies.
组织和细胞的生物学研究带来了众多发现，但由于细胞异质性，这些研究仍存在结果无效的潜在风险。通过高精度技术，最近的研究表明，少量细胞研究结果与基于细胞群体的结果之间确实存在差异。因此，引发了重新评估关于有限数量细胞的关键原则的迫切需求。在本研究中，制备了一种新设计的双核光纤pH微探针，并展示了其用于具有高空间分辨率的微环境pH传感的能力。通过在约70μm大小的探针尖端包埋pH指示剂2',7'-双(2-羰基乙基)-5(6)-羧基荧光素(BCECF)，对有机改性硅酸盐(OrMoSils)溶胶-凝胶薄层进行功能化。在6.20至7.92的生物学相关pH范围内，I/I荧光比率与细胞内pH值之间获得了良好的线性相关性(R = 0.9834)，pH分辨率为0.035±0.005 pH单位。该探针的水平空间分辨率证明小于2mm。此外，通过测量培养的人肺癌细胞(A549)暴露于二氧化钛纳米颗粒(TiO NPs)时局部细胞外pH的变化来评估该探针。结果表明，该探针具有对一小群细胞进行快速、局部和连续监测的卓越能力，为研究人员提供了一种快速准确的技术，用于进行与细胞异质性相关研究的局部pH测量。
