Femtosecond microfabrication techniques, such as multi-photon polymerization, enable the production of precise micro-optics and microneedles. Micro-optics can be directly printed on functional devices, offering possibilities for miniaturized sensing technologies. Microneedles produced through MPP can be used for drug delivery or diagnostics and their shapes can be customized for specific applications. Direct laser writing enables the combination of additive and subtractive technologies to create integrated systems, such as the incorporation of silica and polymer structures for passive chemical sensing applications. Glass microstructures created by selective laser etching can be combined with polymeric structures to study the mechanical properties of polymeric structures.