Yang Qingbo, Wang Hanzheng, Lan Xinwei, Cheng Baokai, Chen Sisi, Shi Honglan, Xiao Hai, Ma Yinfa
Department of Chemistry, Missouri University of Science and Technology, Rolla, MO 65409, USA ; Center of Biological Science and Engineering, Research Center, Missouri University of Science and Technology, Rolla, MO 65409, USA.
Department of Electrical and Computer Engineering, Clemson University, Clemson, SC 29634, USA.
Sens Actuators B Chem. 2015 Feb 1;207(Pt A):571-580. doi: 10.1016/j.snb.2014.10.107.
pH sensing at the single-cell level without negatively affecting living cells is very important but still a remaining issue in the biomedical studies. A 70 μm reflection-mode fiber-optic micro-pH sensor was designed and fabricated by dip-coating thin layer of organically modified aerogel onto a tapered spherical probe head. A pH sensitive fluorescent dye 2', 7'-Bis (2-carbonylethyl)-5(6)-carboxyfluorescein (BCECF) was employed and covalently bonded within the aerogel networks. By tuning the alkoxide mixing ratio and adjusting hexamethyldisilazane (HMDS) priming procedure, the sensor can be optimized to have high stability and pH sensing ability. The real-time sensing capability was then demonstrated in a simple spectroscopic way, and showed linear measurement responses with a pH resolution up to an average of 0.049 pH unit within a narrow, but biological meaningful pH range of 6.12-7.81. Its novel characterizations of high spatial resolution, reflection mode operation, fast response and high stability, great linear response within biological meaningful pH range and high pH resolutions, make this novel pH probe a very cost-effective tool for chemical/biological sensing, especially within the single cell level research field.
在不负面影响活细胞的情况下实现单细胞水平的pH传感非常重要，但在生物医学研究中仍是一个有待解决的问题。通过将有机改性气凝胶薄层浸涂到锥形球形探头表面，设计并制作了一种70μm反射模式光纤微pH传感器。采用了一种对pH敏感的荧光染料2',7'-双(2-羰基乙基)-5(6)-羧基荧光素(BCECF)，并将其共价键合在气凝胶网络中。通过调整醇盐混合比例和优化六甲基二硅氮烷(HMDS)预处理程序，可将该传感器优化至具有高稳定性和pH传感能力。随后以一种简单的光谱方式展示了其实时传感能力，在6.12 - 7.81这一狭窄但具有生物学意义的pH范围内显示出线性测量响应，pH分辨率平均可达0.049 pH单位。其高空间分辨率、反射模式操作、快速响应和高稳定性、在生物学意义pH范围内的良好线性响应以及高pH分辨率等新颖特性，使这种新型pH探头成为化学/生物传感领域，尤其是单细胞水平研究领域中非常经济高效的工具。
