Xu Sihao, Yeow Jonathan, Boyer Cyrille
Centre for Advanced Macromolecular Design and Australian Centre for NanoMedicine, School of Chemical Engineering, The University of New South Wales, Sydney, NSW 2052, Australia.
ACS Macro Lett. 2018 Nov 20;7(11):1376-1382. doi: 10.1021/acsmacrolett.8b00741. Epub 2018 Nov 5.
We report a facile benchtop process for the synthesis of cross-linked polymeric nanoparticles by exploiting wavelength-selective photochemistry to perform orthogonal photoinduced polymerization-induced self-assembly (Photo-PISA) and photo-crosslinking processes. We first established that the water-soluble photocatalyst, zinc meso-tetra(-methyl-4-pyridyl) porphine tetrachloride (ZnTMPyP) could activate the aqueous PET-RAFT dispersion polymerization of hydroxypropyl methacrylate (HPMA). This photo-PISA process could be conducted under low energy red light (λ = 595 nm, 10.2 mW/cm) and without deoxygenation due to the action of the singlet oxygen quencher, biotin (vitamin B), which allowed for the synthesis of a range of nanoparticle morphologies (spheres, worms, and vesicles) directly in 96-well plates. To perform wavelength selective nanoparticle cross-linking, we added the photoresponsive monomer, 7-[4-(trifluoromethyl)coumarin] methacrylamide (TCMAm) as a comonomer without inhibiting the evolution of the nanoparticle morphology. Importantly, under red light, exclusive activation of the photo-PISA process occurs, with no evidence of TCMAm dimerization under these conditions. Subsequent switching to a UV source (λ = 365 nm, 10.2 mW/cm) resulted in rapid cross-linking of the polymer chains, allowing for retention of the nanoparticle morphology in organic solvents. This facile synthesis of cross-linked spheres, worms, and vesicles demonstrates the utility of orthogonal light-mediated chemistry for performing decoupled wavelength selective chemical processes.
我们报道了一种简便的台式方法，通过利用波长选择性光化学来进行正交光诱导聚合引发的自组装（Photo-PISA）和光交联过程，以合成交联聚合物纳米颗粒。我们首先确定水溶性光催化剂四氯中-四（-甲基-4-吡啶基）卟啉锌（ZnTMPyP）可以激活甲基丙烯酸羟丙酯（HPMA）的水性PET-RAFT分散聚合。由于单线态氧猝灭剂生物素（维生素B）的作用，这种Photo-PISA过程可以在低能量红光（λ = 595 nm，10.2 mW/cm）下进行且无需脱氧，从而能够直接在96孔板中合成一系列纳米颗粒形态（球形、蠕虫形和囊泡形）。为了进行波长选择性纳米颗粒交联，我们添加了光响应性单体7-[4-（三氟甲基）香豆素]甲基丙烯酰胺（TCMAm）作为共聚单体，而不抑制纳米颗粒形态的演变。重要的是，在红光下，仅发生Photo-PISA过程的激活，在这些条件下没有TCMAm二聚化的迹象。随后切换到紫外光源（λ = 365 nm，10.2 mW/cm）导致聚合物链快速交联，从而能够在有机溶剂中保留纳米颗粒形态。这种交联球形、蠕虫形和囊泡形的简便合成证明了正交光介导化学在进行解耦波长选择性化学过程中的实用性。
