To better understand the formation of short-chain acids in combustion systems

TL;DR

This paper investigates the transfer and structural characteristics of DNA plasmid complexes from water to silicon surfaces using Langmuir-Blodgett techniques, revealing detailed molecular arrangements and surface interactions.

Contribution

It provides new insights into the transfer mechanism and surface morphology of DNA complexes on silicon, combining spectroscopic and microscopy analyses.

Findings

DNA complexes form a net-like, disordered structure

Transfer process involves spinodal decomposition patterns

DNA molecules condense and aggregate on the substrate

Abstract

Our study aims at a better control and understanding of the transfer of a complex [DNA supercoiled plasmid - dodecyltrimethylammonium surfactant] layer from a liquid-vapour water interface onto a silicon surface without any additional cross-linker. The production of the complexed layer and its transfer from the aqueous subphase to the substrate is achieved with a Langmuir-Blodgett device. The substrate consists of a reconstructed boron doped silicon substrate with a nanometer-scale roughness. Using X-ray photoelectron spectroscopy and atomic force microscopy measurements, it is shown that the DNA complexes are stretched in a disorderly manner throughout a 2-4 nm high net-like structure. The mechanism of transfer of this layer onto the planar surface of the semi-conductor and the parameters of the process are analysed and illustrated by atomic force microscopy snapshots. The molecular layer exhibits the typical characteristics of a spinodal decomposition pattern or dewetting features. Plasmid molecules appear like long flattened fibers covering the surface, forming holes of various shapes and areas. The cluster-cluster aggregation of the complex structure gets very much denser on the substrate edge. The supercoiled DNA plasmids undergo conformational changes and a high degree of condensation and aggregation is observed.