On-chip cell wall separation using magnetic nanoparticles

The separation of bio-particles has increased its importance in recent years. The conventional techniques such as centrifugation is still widely used. The microfluidic chips accompanying nanoparticle separation methods considerably increases the possibility of reducing the time of centrifugation. In this thesis, on-chip magnetophoretic bacterial cell wall separation is presented. In particular, passive micromixing and active separation of cell wall content from the cytoplasmic content of one of the gram-positive bacteria, Staphylococcus aureus, was investigated using magnetic nanoparticles on-chip to serve for more qualified nucleic acid content to examine. To do so, Vancomycin functionalized superparamagnetic iron oxides (Vanco-SPION) nanoparticles were used for the cell wall separation in the range of 10 nm to 300 nm. On-chip studies were carried out using PDMS-made microfluidics chips. Both magnetic nanoparticles and microfluidics devices have unique properties of its own, allowing highly selective analysis within short duration. We believe that the presented results in this thesis pave the way towards effective biosensor based analysis of bacteria and related studies such as antimicrobial resistance.