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Thermal Stability of Thiolated DNA SAMs in Buffer: Revealing the Influence of Surface Crystallography and DNA Coverage via In Situ Combinatorial Surface Analysis
Langmuir ( IF 3.7 ) Pub Date : 2020-11-24 , DOI: 10.1021/acs.langmuir.0c01828
Tianxiao Ma 1, 2 , Isaac Martens 1, 2 , Dan Bizzotto 1, 2
Affiliation  

The thermal stability of thiol based DNA SAMs prepared on gold surfaces is an important parameter that is correlated to sensor lifetime. The thermal stability of DNA SAMs was evaluated in aqueous buffer through the use of fluorophore labeled DNA, a single crystal gold bead electrode, and microscopy. The stability of different crystallographic regions on the electrode was studied for thermal treatments up to 95 °C for 90 min. Using a in situ combinatorial surface analytical measurement showed that the crystallography of the underlying gold surface played a significant role, with the square or rectangular lattices (e.g., 110, 100, 210) having the highest stability. Surfaces with hexagonal lattices (e.g., 111, 311, 211) were less stable toward thermal treatments. These crystallographic trends were observed for both high and low coverage DNA SAMs. High coverage DNA SAMs were the most stable, with stability decreasing with decreasing coverage on average. Increasing DNA SAM coverage appears to slow the kinetics of thermal desorption, but the coordination to the underlying surface determined their relative stability. Preparing the DNA SAMs under nominally similar conditions were found to create surfaces that were similar at room temperature, but had significantly different thermal stability. Optimal DNA sensing with these surfaces most often requires low coverage DNA SAMs which results in poor thermal stability, which is predictive of a poor shelf life, making optimization of both parameters challenging. Furthermore, the crystallographically specific results should be taken into account when studying the typically used polycrystalline substrates since the underlying surface crystallography maybe different for different samples. It appears that preparing DNA SAMs with low coverage and significant thermal stability will be challenging using the current SAM preparation procedures.

中文翻译:

硫代DNA SAMs在缓冲液中的热稳定性:通过原位组合表面分析揭示表面晶体学和DNA覆盖率的影响

在金表面制备的基于硫醇的DNA SAM的热稳定性是与传感器寿命相关的重要参数。通过使用荧光团标记的DNA,单晶金珠电极和显微镜,在水性缓冲液中评估了DNA SAMs的热稳定性。研究了在高达95°C的温度下进行90分钟热处理的电极上不同晶体学区域的稳定性。使用原位组合表面分析测量表明,下面的金表面的晶体学起着重要作用,正方形或矩形晶格(例如110、100、210)具有最高的稳定性。具有六边形格子的表面(例如111、311、211)对热处理的稳定性较差。对于高覆盖率和低覆盖率的DNA SAM都观察到了这些晶体学趋势。高覆盖率DNA SAMs最稳定,稳定性随着平均覆盖率的降低而降低。DNA SAM覆盖率的增加似乎减慢了热脱附的动力学,但与下层表面的配位决定了它们的相对稳定性。发现在名义上相似的条件下制备DNA SAM会产生在室温下相似的表面,但具有明显不同的热稳定性。在这些表面上进行最佳的DNA感测通常需要低覆盖度的DNA SAM,这会导致较差的热稳定性,这预示着较差的保质期,这两个参数的优化都具有挑战性。此外,在研究通常使用的多晶衬底时,应考虑晶体学的特定结果,因为对于不同的样品,其下面的表面晶体学可能会有所不同。看起来,使用当前的SAM制备程序来制备具有低覆盖率和显着热稳定性的DNA SAM将会具有挑战性。使两个参数的优化都充满挑战。此外,在研究通常使用的多晶衬底时,应考虑晶体学的特定结果,因为对于不同的样品,其下面的表面晶体学可能会有所不同。看起来,使用当前的SAM制备程序来制备具有低覆盖率和显着热稳定性的DNA SAM将会具有挑战性。使两个参数的优化都充满挑战。此外,在研究通常使用的多晶衬底时,应考虑晶体学的特定结果,因为对于不同的样品,其下面的表面晶体学可能会有所不同。看起来,使用当前的SAM制备程序来制备具有低覆盖率和显着热稳定性的DNA SAM将会具有挑战性。
更新日期:2020-12-08
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