Magnetolithography: From bottom-up route to high throughput

A bottom-up method based on magnetolithography (ML) providing high-throughput capabilities for mass production was presented. The method was based on applying a magnetic field on the substrate using paramagnetic metal masks that define the spatial distribution and shape of the applied field. The magnetic nanoparticles (NP) are found to immobilize at selected locations, where the mask induces a magnetic field, resulting in a patterned substrate. The scanning electron microscopy (SEM) images of a positive ML pattern show 1-5-μm-wide lines with a 20-μm space between them due to gradient of the magnetic field within the line width defined by the mask. Signal from the fluorescent molecules, Av-FITC, adsorbed on the glass substrate show the irreversible nature of the negative ML process. The results also show that the preadsorbed biotin molecules are deprotected by removing the NPs, after removing the magnetic field.