Microfluidically-generated barcodes can help the battle against counterfeit products

“Scheme of the hydrogel microparticles synthesis. a) Solution containing polymer (PEGDA), photoinitiator and superparamagnetic colloids(SPCs) are pumped through a microfluidic channel. The VMMs placed on the bottom of the channel are magnetized on-demand to trap SPCs. UV light passing through a mask placed at the field stop of the microscope crosslinks the PEGDA to trap SPCs are designated positions. b) Illustration of four steps involved in synthesis from the top view. c) Hydrogel microparticles responds to the external magnetic field and moves from one channel wall to the other when a permanent magnet is brought in contact. Extracted from Movie S1 (Supporting Information). d–g) The microscopy pictures of microparticles of different shapes with SPCs placed at designated position. Their scale bars are all 25 µm. The mask used in synthesis of each particle is given along with a 3D illustration of the microparticle with embedded SPC.” Reproduced under Creative Commons Attribution 4.0 International License from Zhang, M., Warth, T., Boon, N., Demirörs, A. F., Eral, H. B., Microfluidic Synthesis of Hydrogel Microparticles with Superparamagnetic Colloids Embedded at Prescribed Positions for Anticounterfeiting Applications. Adv. Mater. Interfaces 2022, 2200899.