Carbazole‐Based Anion Ionic Water‐Soluble Two‐Photon Initiator for Achieving 3D Hydrogel Structures

Abstract

Abstract3D hydrogel structures fabricated by two‐photon polymerization (TPP) have become attractive in biomedical fields. Generally, conventional organic solvents are toxic and the residues left in the fabricated 3D structures are harmful to cells. Hence, anion ionic carbazole‐based water‐soluble two‐photon initiator (TPI) 3,6‐bis[2‐(1‐methylpyridinium)vinyl]‐9‐methylcarbazole ditosylate (BT) is proposed to construct arbitrary 3D hydrogel structures. Cucurbit[7]uril (CB7) and BT form a host‐guest complex (CB7/BT) with a binding ratio of 1:1, which further improves the water solubility, biocompatibility and nonlinear absorption property of TPI. A water‐soluble photoresist consisting of photoinitiator CB7/BT and monomer poly(ethylene glycol) diacrylate is prepared to explore the TPP fabrication capacity. The electron paramagnetic resonance measurement shows that CB7/BT initiates photopolymerization by alkyl radicals. The laser threshold power of the photoresist is 6.3 mW and the feature size is 127 nm in TPP at 780 nm. The initiator with p‐toluenesulfonate anion exhibits higher binding energy, larger two‐photon absorption cross‐section and two‐photon fabrication resolution compared with the previous work using iodide as an anion, indicating a promising way to improve the fabrication capacity of water‐soluble TPI through changing the anion ionic group. The proposed strategy will provide high potential for the further application in the biomedical field.

Iridium(III)-Based Infrared Two-Photon Photosensitizers: Systematic Regulation of Their Photodynamic Therapy Efficacy

“…The Ir­(III)-PSs in this study produce remarkable TP-induced fluorescence signals in the range of 720–880 nm with no apparent σ maxima (Figure e). The logarithm plots of the TP-induced fluorescence intensities ( F ) of Ir­(III)-PSs exhibited a linear relationship to the excitation intensities at 800 nm ( I ) with slopes close to 2.0 (Figure S10), indicating the TPA characteristic . Since many TPA-PSs with σ 808 lower than 100 GM have been successfully applied in antitumor PDT, the Ru–Os complexes in this study can be expected to be more active in TP-excited antitumor PDT under 808 nm irradiation.…”

“…The logarithm plots of the TP-induced fluorescence intensities (F) of Ir(III)-PSs exhibited a linear relationship to the excitation intensities at 800 nm (I) with slopes close to 2.0 (Figure S10), indicating the TPA characteristic. 45 Since many TPA-PSs with σ 808 lower than 100 GM have been successfully applied in antitumor PDT, the Ru−Os complexes in this study can be expected to be more active in TP-excited antitumor PDT under 808 nm irradiation. The σ values at 808 nm (σ 808 , Table 1) were 124−391 GM (1 GM = 10 −50 cm 4 s photon −1 ), which are not only higher than similar mononuclear Ir(III) 27,34,46 and Ru(II) 47−51 complexes at around 800 nm but quite comparable to certain dinuclear Ir(III), 52 Ru(II), 25,53 and Os(II) 54 complexes.…”

Heterometallic ruthenium–osmium complexes: dual photodynamic and photothermal therapy for melanoma and drug-resistant lung tumourin vivo

“…2f), which was a TPA characteristic. 25 Because many TPA-PSs with a σ 808 lower than 100 GM have been successfully applied in antitumour PDT, the Ru–Os complexes in this study were expected to be more active in the TP-excited antitumour PDT under 808 nm irradiation.…”

Two-photon microprinting of 3D emissive structures using tetraazaperylene-derived fluorophores

“…Many improvements have been made in terms of printing feature size, resolution and printing speed using two-photon laser printing in the past few years. 2,3 Furthermore, the library of printable functional materials has also widely expanded, [4][5][6][7][8][9][10][11] and thus achieving advanced applications, ranging from actuators, microfluidics, photonics, to biomedical devices etc. 12,13 Although luminescent materials having been widely applied in applications such as sensors, anti-counterfeiting devices or biomedicines, their use in 3D microfabrication, especially in high resolution two-photon laser printing, is still limited.…”