DNA combing on low-pressure oxygen plasma modified polysilsesquioxane substrates for single-molecule studies

Molecular combing and flow-induced stretching are the most commonly used methods to immobilize and stretch DNA molecules. While both approaches require functionalization steps for the substrate surface and the molecules, conventionally the former does not take advantage of, as the latter, the versatility of microfluidics regarding robustness, buffer exchange capability, and molecule manipulation using external forces for single molecule studies. Here, we demonstrate a simple one-step combing process involving only low-pressure oxygen (O₂) plasma modified polysilsesquioxane (PSQ) polymer layer to facilitate both room temperature microfluidic device bonding and immobilization of stretched single DNA molecules without molecular functionalization step. Atomic force microscopy and Kelvin probe force microscopy experiments revealed a significant increase in surface roughness and surface potential on low-pressure O₂ plasma treated PSQ, in contrast to that with high-pressure O₂ plasma treatment, which are proposed to be responsible for enabling effective DNA immobilization. We further demonstrate the use of our platform to observe DNA-RNA polymerase complexes and cancer drug cisplatin induced DNA condensation using wide-field fluorescence imaging.     

MSA在24表位TD3500型终端检定装置误差检验中的应用

随着我国智能电网由全面建设阶段到引领提升阶段的逐步推进,电能计量的准确性越来越重要,这就要求智能电表误差指标越来越严格.电表出厂前都必须在检定装置上对其进行误差检验,因此误差检验系统能否满足要求非常重要.本文以24表位TD3500型电表误差测量系统为研究对象,设计了该测量系统的分析方案,制定了该测量系统的分析计划,首先分析了该测量系统的稳定性、偏倚和线性,在这3个指标满足要求之后,再分析该测量系统的重复性和再现性,其％GR&R指标为9.77％＜10％,且可区分的类别数等于18＞5,表明该测量系统可以接受.