Immobilization of single strand DNA on solid substrate

Abstract

Thin films based on Layer-by-Layer (LbL) self assembled technique are useful for immobilization of DNA onto solid support. This communication reports the immobilization of DNA onto a solid support by electrostatic interaction with a polycation Poly (allylamine hydrochloride) (PAH). UV-Vis absorption and steady state fluorescence spectroscopic studies exhibit the characteristics of DNA organized in LbL films. The most significant observation is that single strand DNA are immobilized on the PAH backbone of LbL films when the films are fabricated above the melting temperature of DNA. DNA immobilized in this way on LbL films remains as such when the temperature is restored at room temperature and the organization remains unaffected even after several days. UV-Vis absorption spectroscopic studies confirm this finding.Comment: Eight pages, five figure

Sensing of DNA conformation based on change in FRET efficiency between laser dyes

“…This causes an abrupt decrease in the absorption intensity. In one of our earlier work we have demonstrated the immobilization of denatured single stranded DNA in LbL films [15], where it has been observed that the absorption intensity increases for DNA LbL films prepared up to 80 0 C and beyond this temperature the absorption intensity decreases.…”

“…As a result the absorption intensity maximizes. Also the length of transition dipole moment vector increases due to breaking of H-bridges with increasing temperature [15]. This in turn increases the absorption intensity.…”

“…This in turn increases the absorption intensity. The increase in temperature after 80 0 C results in a remarkable decrease in absorption intensity which is obtained due to coil formation of the totally denatured DNAs [15]. The coil formation of DNA results a remarkable decrease in the length of the transition dipole moment vector.…”

“…From figure 2(a) it is observed that the absorbance intensity of 260 nm band of DNA-PAH LbL films increases abruptly with increase in pH and almost at pH 11 it becomes maximum. At higher pH the denaturation of DNA occurred resulting in a increase in absorbance intensity [15,26]. There are several reports on the denaturation and renaturation of DNA with pH variation based on the hypochrometic shift of DNA absorbance [15,26].…”

“…At higher pH the denaturation of DNA occurred resulting in a increase in absorbance intensity [15,26]. There are several reports on the denaturation and renaturation of DNA with pH variation based on the hypochrometic shift of DNA absorbance [15,26]. It is interesting to mention in this context that due to the increase in pH or temperature, the H-bond in the double stranded DNA is disrupted and the strands are no longer held together, that is the double helix structure is denatured and the strands separate from each other and finally form individual random coils.…”