The association of DNA/RNA to mineral surfaces is an emerging field with widespread applications from biotechnological solutions to paleogenetics. Evaluating available methods to quantify adsorption will be essential to further investigate how to control and predict loading of DNA onto minerals. This study aims to test some of the available techniques for DNA quantification by investigating sorption onto Montmorillonite (Mnt) and Kaolinite (Kao) clay minerals, exchanged with different counter-cations. UV-Vis spectroscopy was successfully used in quantifying bulk DNA. Fluorescent techniques showed less reproducibility in this study but is inherently a more sensitive method demanding a more sophisticated protocol. In theory, with the right sample preparations the method can be both selective and sensitive. With pure samples and lacking a defined fluorescent protocol UV-Vis was determined to be the method of choice. To test the influence of different counter-cations, Mnt and Kao clays were washed and exchanged with Na+, K+, Ca2+, and Mg2+ and used in the DNA sorption experiments. In solutions with monovalent ions, DNA associated strongest to Kao while in solutions with divalent ions DNA associated strongest to Mnt, as quantified by the sorption coefficient Kd. Overall, the Kd values increased in the order of Na+ < K+ < Ca2+ < Mg2+ for both minerals, with the major difference between the results being the case of monovalent and divalent cations which is in agreement with previous studies. Interestingly, when confirming mineralogy of the clay samples using powder XRD, an additional first order reflection was found in samples prepared at high temperatures (<80˚C) indicating a composite material. The distance and higher temperatures required suggest single stranded DNA could be intercalated in the Na+-exchanged Mnt. Further investigations of what ionic property determines the facilitation of DNA adsorption and the suspected DNA intercalation should be conducted.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:umu-198741 |
| Date | January 2022 |
| Creators | Wangdell, Oskar |
| Publisher | Umeå universitet, Kemiska institutionen |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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