DNA immobilisation

The determination of such compounds was measured by their effect on the oxidation signal of tire guairine peak of calf tlrymus DNA immobilised on tire electrode surface and investigated by chronopotentiometric or voltammetric analysis. Applicability to river and wastewater samples is demonstrated. 

The substrates used for DNA immobihsation can be, at the level of the AFM analysis, either rigid (e.g., glass) or flexible (e.g., polymers). An atomically flat surface is preferable, but sometimes this is difficult to achieve. The DNA immobilisation mechanisms can be (i) physio-sorption, (ii) charge complementarity and (iii) covalent binding. Depending on the actual objective of the AFM study, each combination of the surface-immobilisation mechanism has both benefits and drawbacks. 

Fig. 26.3. Influence of temperature on DNA immobilisation. C — 1 gM, ydrop = 5pL. Reprinted from Ref. [9], Copyright 2005, with permission from Elsevier.

There is an increasing need for DNA to have a greater degree of conformational freedom on a surface. Thomson et al. [64] found that both pH and ionic strength influenced the degree of DNA immobilisation, allowing us to... 

The first discussion of DNA immobilisation by monovalent ions was published in 1991 [103], where both monovalent and divalent ions were used to immobihse DNA to quartz sand. A recent publication [3] cited, for the first time, direct AFM evidence of monovalent ion immobilisation of DNA. Here, plasmid DNA was diluted in 10% PBS and incubated for either 10 min or 24 h at room temperature. After incubation, DNA was imaged on untreated, freshly cleaved mica using TM-AFM. The mobility of DNA could be observed with both immobilisation times. However, the immobilisation... 

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