Identification-Tagging of Methacrylate-Based Intraocular Implants Using Sequence Defined Polyurethane Barcodes

Sequence-coded polyurethanes are tested as anticounterfeiting tags for the labeling of methacrylate-based intraocular implants. These sequence-defined oligomers are prepared by solid-phase iterative chemistry using two co-monomers, allowing formation of a controlled 0/1 binary sequence. Tags with different sequences and chain lengths are synthesized and tested for lenses labeling. Two main methods are investigated for incorporating the tags in the intraocular implants. In the first approach, they are included in situ during the free-radical copolymerization of 2-ethoxyethyl methacrylate and ethylene glycol dimethylacrylate. In another strategy, premade lenses are swollen in a tetrahydrofuran solution containing the polyurethane tags and dried. Both approaches allow successful incorporation of the polyurethane labels in the methacrylate networks. In order to demonstrate this, the tags are extracted from the lenses using a solvent swelling protocol and analyzed by electrospray mass spectrometry. In all cases, the labels are found and their coded sequences can be identified by tandem mass spectrometry sequencing. These results indicate that sequence-coded polyurethane tags represent a valid option for the labeling of implants. Importantly, it is shown in this work that the use of small weight fractions of polyurethane tag (i.e., 0.1-0.4 wt%) do not alter significantly the biocompatibility and transparency properties of the intraocular lenses.