RecA-templated DNA scaffolds for selective site-specific assembly of nanoparticles for electronic devices

With today’s challenges in the electronic industry, novel alternative ap- proaches for manufacturing devices at nanoscale are being investigated. Using self-assembly, arguably has the best potential for nanostructures. DNA and proteins - some of the most important biomolecules use self- assembly extensively for natural functions. Chemical and structural pre- dictability of DNA and specificity of proteins promise a big potential for novel materials and could allow creation of structures controlled at nanoscale level. RecombinaseA - a DNA-binding protein has been used for controllable and predictable patterning of selected DNA sequences, opening the way to nanometre-scale DNA marking. However, protein patterning alone does not add any electric or other desired functionality to the DNA, there- fore additional modifications are neccessary. Furthermore, since biologi- cal molecules have transient functionality, system stability investigation is crucial for needed modification and subsequent usage. This project focused on RecA-patterned DNA modification for electric prop- erty addition. Thiolation and subsequent attachment of gold or magnetic nanoparticles to RecA protein present on DNA were investigated as a method for creating electrically conductive nanoscale objects. More specifically, at- tachment of gold nanoparticles throughout the whole patterned region of DNA and attachment of single nanoparticles at precise positions were looked into. The work successfully demonstrated that both nanoparticle deposition along the full length of RecA-coated DNA and specific single nanoparticle positioning is feasible. For investigating RecA-DNA stability, a system based on FRET was de- vised and used to analyse interaction kinetics. It was found that RecA-DNA complexes are fully formed in minutes and stay bound for hours. Specific configurations of the set-up showed distinct lack of signal, suggesting com- plicated interactions between the protein and patterned DNA. The project demonstrated through binding of NPs at specific locations and on the whole filament length that the system has potential for electronic applications and its stability is sufficient for processing times.