Dr. McLeod's research is at the intersection of optics and soft materials. That is, the lab develops novel optical patterning techniques to structure new forms of polymers which are then measured with optical imaging methods created specifically for this purpose. One example is a new form of semiconductor lithography that can pattern material at scales well below the traditional diffraction limit. Another project is using laser trapping to position live cells in a hydrogel matrix for the creation of precise tissue scaffolds that can answer fundamental questions in cellular biology. We create new forms of stereolithographic 3D printers and investigate the fundamentals of the printing process. Much of our work involves gels, in which a liquid such as a monomer, water or ionic fluid, is forced to move through a polymer host due to chemical reaction or electric field. This causes the shape, refractive index, color or conductivity of the gel to change permanently or reversibly.