The ability to locally functionalize the surface of glass and polymers allows for myriad biomedical and chemical applications. When we started this research in 2015, enclosed surfaces such as microfluidic channels were not easily amenable to localized functionalization. Furthermore, pre-functionalization of microfluidic devices was incompatible with the typical high-temperature substrate bonding procedures. The work described in this thesis successfully tackled these issues. We showed how light can be used to pattern DNA onto enclosed glass. Additionally, this thesis shows how typically considered “inert” plastics can be quickly modified in water at room temperature. Finally, laser-based technologies were used to study the low-temperature fabrication of micro-devices.