271325 Microreactors for Click Chemistry Based Conjugation
Click chemistry has been used in a myriad of applications across several scientific fields, including organic chemistry, medicinal chemistry, and chemical biology. Specifically, the Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) is used extensively in nuclear medicine for the synthesis of radiotracers utilized in molecular imaging procedures. CuAAC offers a chemoselective method of conjugating a bifunctional chelator to a targeting biomolecule. This copper catalyzed reaction's chemoselective nature provides an assimilation system that can easily be adapted for other imaging modalities or biomolecules.
Despite the high yields achievable by a CuAAC reaction, it's use is plagued by limitations inherent to conventional techniques for chemical synthesis. These techniques require large volumes of expensive reagents, and possess inadequate flexibility to optimize the procedure. Microfluidics provides a method for efficient, rapid chemical synthesis due to enhanced heat and mass transfer, and also requires low reagent volumes. Working on the microscale allows a high-throughput method for the synthesis and functional study of a library of cancer imaging agents. In conjunction with click chemistry, microfluidic platforms afford an efficient, rapid, versatile system for conjugation.
This study specifically focused on the impact of heterogeneous catalysis on CuAAC in a microreactor. Experiments included the effects of flow rates and length of reactor on product yields and synthesis time. The conjugation of azide-fluor 568 to propargylamine was used as a test reaction to confirm the benefits of using heterogeneous click chemistry catalysis on chip.