Droplet-based microfluidic systems are particularly advantageous for controlling the size and composition of micro-and nanoparticles.Furthermore,surface-enhanced Raman scattering(SERS)is a promising tool for particle-based sensor platforms.Well-defined chemical compositions and tailored physicochemical properties are the requirement for using such particles for sensitive detection.A real challenge is to obtain reproducible and homogeneous nano-and micro particles in a minimum number of preparation steps.In our work,a single-step microflow process has been successfully implemented for the production of multi-scale sensor particles.