ABSTRACT
Objective To investigate the influences of drop components on the"coffee ring" test of DNA. Methods The DNA-EB drops containing SDS, NaCl, etc, were evaporated on glass slides. After evaporation, the fluorescent Deposition Pattern (DP) and Integrated Optical Density (IOD) was acquired with a gel imaging system. The dose-effect relationship was analyzed. Result When the non-DNA components concentration is low, the DP was still characteristiced by peripheral rings, subtle component-specific differences, such as tree-ring like structure and radial crack, existed. At high concentrations, DP was various, which may be ring + scattered dots (NaCl), central spot + small weak ring (SDS), concentric/tree-ring (TritonX-100) or ring + spot (H+), et al. Non-DNA components had little effect on IOD(0.5~2 times). Conclusion Non-DNA components in DNA-EB drops influences both the DP and IOD, but rough estimation of DNA concentrations is still effective. Moreover, analyzing the DP can provide more informations about sample purity and residue.
ABSTRACT
Objective To explore the feasibility of "coffee ring" effect in DNA high-throughput evaluation. Methods we mixed uniformly DNA solution and EB solution, then dripped different size of droplets on 5 kinds of substrates. After evaporation, the coffee ring was observed and photographed with LG2020 gel imaging analysis system. Analyzed the correlation among ring formation conditions,ring fluorescence intensity and DNA concentration, and looked for the sensitivity and applicable range of the method. Result DNA - EB solution can form fluorescent ring after surface evaporation on the slide, transparent polystyrene plate carrier and so on. The DNA detection limit can be up to 2ng/μl. DNA concentration and loop integral optical density fitting Logistic equation(R2=0,999) within 2ng/μl~1000ng/μl. Conclusion The coffee ring method is simple, fast and low equipment requirement,which can be used for high-throughput evaluation of DNA solution.