Reversible addition-fragmentation chain-transfer (RAFT) polymerization is a powerful tool for synthesizing macromolecules with controlled topologies and diverse chemical functionalities. In 2014, we reported an efficient activation of RAFT polymerization by the introduction of photocatalysts, named photoinduced electron/energy transfer – reversible addition fragmentation chain transfer (PET-RAFT) polymerization,1 allowing to activate these RAFT polymerizations under low energy and intensity visible light and without prior deoxygenation.2-3 In this talk, we will provide an overview of their potential applications in additive manufacturing (3D printing) and in nanomedicine. The application of RAFT polymerization to additive-manufacturing processes has been hindered due to their slow polymerization rates and sensitivity to oxygen.4-5 In this talk, we report a rapid visible light mediated RAFT polymerization process and applied it to a 3D printing system.6 The photosensitive resins contained a photocatalyst and a trithiocarbonate RAFT agent to afford polymerization without prior deoxygenation. Following the optimization of the resin formulation by varying the ratio of photocatalyst, a variety of 3D printing conditions were investigated to prepare functional materials.7 The mechanical properties of these 3D printed materials were investigated under different conditions, showing that the addition of RAFT affect the performance of these materials.8 Furthermore, the trithiocarbonate species incorporated in the polymer networks were able to be reactivated after the initial 3D printing process, which allowed the post functionalization of the printed materials via secondary photopolymerization processes.9 Finally, the incorporation of polymers terminated by RAFT agent was employed for the preparation of 3D printed multimaterials with a precise control of the nanostructure of these materials.10 We will discuss the effect of nanostructure of 3D printed materials on their mechanical properties and present their potential applications as energy devices. In a second part of this talk, taking advantages of the oxygen tolerance conferred by PET-RAFT technique, multiple parallel polymerizations were achieved enabling the synthetic optimization of functional polymers, which were used for the delivery of therapeutic agents, such as siRNA.11 More specifically, we prepared a library of anti-microbial/fungal polymers and test their antimicrobial activities against different bacteria.12-13 Interestingly, we demonstrated that their anti-microbial and anti-fungal activity is affected by the monomer sequence in the polymer chain as well as by the monomer structure and polymer composition.14-15
1. Xu, J.; Jung, K.; Atme, A.; Shanmugam, S.; Boyer, C., A robust and versatile photoinduced living polymerization of conjugated and unconjugated monomers and its oxygen tolerance. J. Am. Chem. Soc. 2014, 136 (14), 5508-5519.
2. Shanmugam, S.; Xu, J.; Boyer, C., Exploiting Metalloporphyrins for Selective Living Radical Polymerization Tunable over Visible Wavelengths. J. Am. Chem. Soc. 2015, 137 (28), 9174-9185.
3. Shanmugam, S.; Xu, J.; Boyer, C., Light-Regulated Polymerization under Near-Infrared/Far-Red Irradiation Catalyzed by Bacteriochlorophyll a. Angew. Chem. Int. Ed. 2016, 55 (3), 1036-1040.
4. Bagheri, A.; Fellows, C. M.; Boyer, C., Reversible Deactivation Radical Polymerization: From Polymer Network Synthesis to 3D Printing. Adv. Sci. 2021, 8 (5), 2003701.
5. a) Wu, C.; Chen, H.; Corrigan, N.; Jung, K.; Kan, X.; Li, Z.; Liu, W.; Xu, J.; Boyer, C., Computer-Guided Discovery of a pH-Responsive Organic Photocatalyst and Application for pH and Light Dual-Gated Polymerization. J. Am. Chem. Soc. 2019, 141 (20), 8207-8220; b) Wu, C.; Jung, K.; Ma, Y.; Liu, W.; Boyer, C., Unravelling an oxygen-mediated reductive quenching pathway for photopolymerisation under long wavelengths. Nat. Commun.2021, 12 (1), 478.
6. Zhang, Z.; Corrigan, N.; Bagheri, A.; Jin, J.; Boyer, C., A Versatile 3D and 4D Printing System through Photocontrolled RAFT Polymerization. Angew. Chem. Int. Ed. 2019, 58 (50), 17954-17963.
7. Zhang, Z.; Corrigan, N.; Boyer, C., A Photoinduced Dual-Wavelength Approach for 3D Printing and Self-Healing of Thermosetting Materials. Angew. Chem. Int. Ed. 2022, 61, 11, e202114111.
8. Shi, X.; Zhang, J.; Corrigan, N.; Boyer, C., Controlling mechanical properties of 3D printed polymer composites through photoinduced reversible addition–fragmentation chain transfer (RAFT) polymerization. Polym. Chem. 2022, 13 (1), 44-57.
9. Lee, K.; Corrigan, N.; Boyer, C., Rapid High-Resolution 3D Printing and Surface Functionalization via Type I Photoinitiated RAFT Polymerization. Angew. Chem. Int. Ed. 2021, 60 (16), 8839-8850.
10. a) Bobrin, V. A.; Lee, K.; Zhang, J.; Corrigan, N.; Boyer, C., Nanostructure Control in 3D Printed Materials. Adv. Mater. 2022, 34 (4), 2107643. b) Shi, X., Bobrin, V.A., Yao, Y., Zhang, J., Corrigan, N. and Boyer, C..A.J.M. Designing Nanostructured 3D Printed Materials by Controlling Macromolecular Architecture. Angew. Chem. Int. Ed. 2022, https://doi.org/10.1002/anie.202206272; c) Bobrin, V. A.; Yao, Y.; Shi, X.; Xiu, Y.; Zhang, J.; Corrigan, N.; Boyer, C., Nano- to macro-scale control of 3D printed materials via polymerization induced microphase separation. Nat. Commun. 2022, 13 (1), 3577.
11. Sharbeen, G.; et al. Cancer-Associated Fibroblasts in Pancreatic Ductal Adenocarcinoma Determine Response to SLC7A11 Inhibition. Cancer Research 2021, 81 (13), 3461-3479.
12. Jung, K.; Corrigan, N.; Wong, E. H. H.; Boyer, C., Bioactive Synthetic Polymers. Adv. Mater. 2022, 34 (2), 2105063.
13. Namivandi-Zangeneh, R.; Wong, E. H. H.; Boyer, C., Synthetic Antimicrobial Polymers in Combination Therapy: Tackling Antibiotic Resistance. ACS Infect. Dis. 2021, 7 (2), 215-253.
14. Schaefer, S.; Pham, T. T. P.; Brunke, S.; Hube, B.; Jung, K.; Lenardon, M. D.; Boyer, C., Rational Design of an Antifungal Polyacrylamide Library with Reduced Host-Cell Toxicity. ACS Appl. Mater. Interf. 2021, 13 (23), 27430-27444.
15. Judzewitsch, P. R.; Nguyen, T.-K.; Shanmugam, S.; Wong, E. H. H.; Boyer, C., Towards Sequence-Controlled Antimicrobial Polymers: Effect of Polymer Block Order on Antimicrobial Activity. Angew. Chem. Int. Ed. 2018, 57 (17), 4559-4564.